Chlorine - bane or benefit? : Proceedings of a conference on

CHLORINE -

BANE OR BENEFIT?

Proceedings of a Conference on the Uses of Chlorine in Estuaries

Chesapeake Bay

Foundation

/y^MCitizens Program

for the

Chesapeake Bay

DRC Chesapeake Research

Consortium

April 1982

g-s-so'vy

201001482

CHLORINE - BANE OR BENEFIT?

Proceedings of a Conference On The Uses of Chlorine In Estuaries

May 27 and 28, 1981 Mary Washington College Fredericksburg, Virginia

Sponsored by

Chesapeake Bay Foundation Chesapeake Research Consortium

Citizens Program for the Chesapeake Bay

With additional support from German Marshall Fund

Maryland Association of Bay Pilots Office of Environmental Programs, Maryland Dept. of Health and Mental Hygiene

U.S. Environmental Protection Agency

April, 1982

Chesapeake Bay Foundation

162 Prince George Street Annapolis, MD

21404

Chesapeake Research Consortium, Inc. 4800 Atwell Road Shady Side, MD

20764

Citizens Program for Chesapeake Bay 6600 York Road Baltimore, MD

21212

FRONTISPIECE

CHLORINE LOADINGS FROM SEWAGE

TREATMENT PLANTS

ON THE CHESAPEAKE BAY

KEY

- 1-100 lbs/day

SCALE OF MILES 10 0 10

CHESAPEAKE

BAY

Data from July-Dec. 1979

Prepared by the Chesapeake Bay Foundation from data from MD/DHMH and VA/SWCB

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PREFACE

The proceedings of the conference titled "Chlorine: Bane or Benefit?" are recorded in this publication. As the title implies, the purpose of the conference was to focus attention on the benefits and problems associated with a wide range of chlorine uses in the Chesapeake Bay and to investigate and .assess possible alternatives to those uses of chlorine. Conference planners directed the attention of the speakers and audience toward the establishment of guidelines for chlorine use which will help to ensure the optimal protection of the Chesapeake Bay ecosystem.

The sponsoring organizations found a useful common cause in this effort to broaden public understanding and improve future management decisions. The Chesapeake Bay Foundation is a private, non-profit public interest organization dedicated to promoting the sound management of Chesapeake Bay's natural resources, principally through environmental education and resource representation. The Chesapeake Research Consortium is a planning and coordination center for research on the Bay among the University of Maryland, The Johns Hopkins University, the Smithsonian Institution and the Virginia Institute of Marine Science. The Citizens Program for Chesapeake Bay is a private, non-profit organization of organizations dedicated to citizen participation in decisions affecting use and management of the Bay's resources.

In addition to financial support from the sponsoring organizations, contributions were received from the U.S. Environmental Protection Agency, the Maryland Association of Bay Pilots, and the German Marshall Fund. The Office of Environmental Programs of the Maryland Department of Health and Mental Hygiene generously arranged for printing of these Proceedings. A ten dollar registration fee was also received from each of the 150 audience participants.

The Conference Committee appreciates the essential contributions of the speakers and participants to the conference. The committee Would also like to thank Mary Brady, Mary Tod Winchester, Kitty Cox, Jennifer Young, Helen Collins, the administration of Mary Washington College and the staff members of the three sponsoring organizations for their dedicated work.

Conference Committee L. Eugene Cronin, Chairman - William C. Baker Charles W. Coale, Jr. Mary E. Kasper David B. McGrath J. Kevin Sullivan

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CONTENTS j

INTRODUCTION page

Partnership for the Bay, or "Who Cares About Chlorine?" John Gottschalk 4

Major Uses of Chlorination (An Ecologist's Perspective) William P_. Davis 8

Chlorine Chemistry George j*. Helz 19

EFFECTS

Acute Toxicity Potential of Chlorination in Estuarine Waters Morri s Roberts, Jr 28

Sublethal Effects of Chlorine-Produced Oxidents on Estuarine Organisms (Abstract)

Chae Laird 36

The Association of Chlorine Pollution and Over-Grazing in Destroying the Aquatic Plant Community of the Upper Half of the Potomac Estuary (Abstract)

Horace Wester 37

On the Risks (Abstract) Victor Cabel1i 39

The EPA Position (Abstract) Allan Rubin 41

Discussion of Effects 43

A CHALLENGE AND RESPONSE

A Challenge to Chlorination Peter H^ Garnett 57

Disinfection of Sewage Effluent - The American Approach Vi ncent 01 i vi eri 70

Responses to Dr. Garnett's Questions Catherine I. Ri 1 ey 81 Evelyn M7 Hai ley 81 Wi11iam M. Eichbaum 82

ALTERNATIVES

Sewage Chlorination: "Status Quo" C. M. Sawyer 84

Dechlorination of Wastewater: State-of-the-Art Discussion Davi d vh Greene 98

Ozone: Alternative to Chlorine Bruce Burns 101

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Page

Ultraviolet Light as a Disinfection Alternative 0. Karl Scheible 106

Bromochlori nation Norman LeBlanc -j 13

Disinfection in Wastewater Treatment Under the EPA's Innovative Alternative Program

James F. Wheeler 123

Economic Aspects of Alternative Modes of Disinfection Mark Alpert and John D. Bonono 133

Wastewater Treatment and Disinfection Alternatives for the Chesapeake Bay Seafood Processing Industry

Russell B.Brinsfield 13g

Chlorine Use in Broiler Processing Plants - Status Quo Lewis E. Carr 147

The Uses of Chlorine and Potential Alternatives in the Tri-State Vegetable Processing Industry

Donald V. Schlimme 1^3

Alternatives to Chlorination for Controlling Biofouling in Cooling Water Systems of Steam Electric Generating Stations

Dennis T. Burton, Lenwood W. Hall, Jr 157

DISCUSSION OF ALTERNATIVES 170

CONFERENCE WORKSHOPS 178

DISCUSSION OF MANAGEMENT STRATEGIES

David McGrath 1 gg Calmet Sawyer 1 on Evelyn Hailey 1^ Catherine I_. Ri 1 ey 1 g2 James B. Coulter - 1g5

Cranston Morgan 152 Wi Hi am M. Ei chbaum and Mary Jo Garreis 10^ Michael Bellanca 199

CLOSING COMMENTS

L. Eugene Cronin 202

REGISTRANTS one

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A PARTNERSHIP FOR THE BAY, OR "WHO CARES ABOUT CHLORINE?"

John S. Gottschalk

Citizens Program for the Chesapeake Bay, Inc. Hampton, Virginia 23669

People have become accustomed to the idea that nothing is sacred. There is always someone around the corner about to debunk a hero or prove that a good thing we have taken for granted is really evil. These periodic revelations have almost become a bit boring or worse yet, frustrating, because the average individual really has no basis for making an intellegent judgment about the credentials of the person doing the debunking-- the iconoclast. Therefore, we face the inevitable quandry of not knowing what to believe or what to do about such relevations.

Part of our dilemma, of course, lies in the mania of the public media for attention-getting stories. We are besieged on all sides by the media's efforts to engage our conscious faculties. The television is usually considered the worst of- fender because so much coming over the air waves is junk or worse. However, wherever one looks, the incessant effort to catch and keep our eyes and ears, even for an instant, goes on apace.

Fortunately, we can extricate ourselves from these dilemmas and gain some better insight into what is the "real truth". In the process we have to remember that what is truth today, may not be tomorrow, and what is truth in Fredericksburg, may be fiction in some other community. Still, we can go to the library to do our own research, or we can talk with those having scholarly knowledge and judgement. Furthermore, we can attend a workshop or symposium to listen to knowledgeable people discuss the matter of immediate interest.

That, of course, is why we are here today--to hear about the effects.of chlorine and thereby, to gain a better insight into one of the most challenging environmental problems facing those who are concerned about the Chesapeake Bay.

Perhaps this would be the appropriate time to tell you a bit about the sponsors of this conference. You will be hearing from us over the next couple of days.

First, the Chesapeake Research Consortium, with Dr. L. Eugene Cronin as its director, is an organization created to coordinate the research of the four primary educational and research organizations doing work on the problems of the Chesapeake Bay. These organizations include the Johns Hopkins University, the Smithsonian Institution, the University of Maryland, and the

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Virginia Institute of Marine Science. In its relatively short life the Consortium has earned recognition as the calm but strong voice of reason and logic in affairs of the Bay. One of its many efforts was putting together the landmark Bi-State Con- ference on the Chesapeake Bay which was held in April 1977 at the Patuxent Naval Air Test Center. The discussions occurring during that conference and the resulting Proceedings are recognized as an important starting point for developing many of the plans and programs which we tend to take for granted today. Most importantly, during the conference, officials from Mary- land and Virginia pledged their best efforts to provide an ongoing cooperative framework for conducting official activities concerning the Chesapeake Bay.

The next sponsor, the Chesapeake Bay Foundation (CBF), is the organization which most citizens consider the primary entity devoted to preserving the Chesapeake Bay and its many values. Headed by President Godfrey Rockefeller and David McGrath, Executive Director, the Foundation is the foremost private educational entity on the Bay. Through its broad educational program that ranges from canoe trips in Bay marshes to formal lectures on Bay ecology to several thousands of "SAVE THE BAY" bumper stickers , CBF is the organization most people look to for guidance in Bay matters.

The Citizen's Program for the Chesapeake Bay, Inc., (CPCB), with Cranston Morgan as its Board Chairman and myself as Presi- dent, is the last sponsor. An organization of organizations, the CPCB promotes public discussion about Bay affairs by sponsoring neutral forums. In addition, it supervises several projects designed to foster greater public interest and involvement in Bay issues. The largest of these projects is the management of the public participation aspects of the EPA Chesapeake Bay Research Program. Another, funded by a grant from the National Science Foundation, involves a planning study which should lead to the establishment of a Chesapeake Bay Information Center. The organization is also completing a Bay User Ethics project with financial support from the Virginia and Maryland Councils for the Humanities. Funded by the Virginia Environmental Endow- ment CPCB also administers a mini-grants program to promote greater public interest in the Chesapeake as a great national resource. A loose but effective partnership, CPCB promotes increased public knowledge and concern about maintaining the vitality of the Bay.

Even if the Bay was not what it is--a great national resource—we should still be concerned about her. However, the Chesapeake is still the "Queen of Estuaries", "rich in a variety of natural, commercial and other resources, including environmental natural beauty...of immediate and potential value to the present and future generations of Americans."

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The Bay contributes significantly to the lives of millions. The great metropolitan centers of the upper and lower Bay depend directly on Bay-related commerce and industry for much of their income. Of course, dozens of smaller cities and villages are even more directly related to this great estuary which may be the microcosm of all life's experience for some. For instance, the entire society, cultural and economic, of the island communities of Tangier and Smith, reflects their profound dependence upon the Bay.

The neighboring society generally takes for granted its dependence on the Chesapeake Bay for commerce and industry. After all, the Bay is still producing lots of oysters and crabs, although the prices have gone up; and fishing is still pretty good, although the species have changed. Furthermore, there is still a lot of room for boating even though things get a bit hectic around Annapolis on a pleasant summer afternoon; and while duck hunting has declined, goose hunting has never been better.

i

So what do we have to be concerned about?

The same things that concerned some people ten and perhaps twenty or more years ago are still concerns. Factors adversely affecting estuaries then are still at work, but considerable progress has been made. For instance, filling of important wetlands is now under reasonable control in both Maryland and Virginia, although the insidious nibbling away of small pieces of wetland will one day be considered a major problem.

Pollution, another familiar problem, is not nearly as serious in many parts of"the country as it was ten years ago. Although as we learn more, we will continue to find out how little we know. However, there is reason for optimism that we can continue to establish effective controls over the deterior- ation of our waters. In the Chesapeake; effective control is a large problem since it is affected greatly by the actions, or lack thereof, of upstream neighbors who see little direct reason to be concerned about the impacts they might have on the Bay.

Furthermore, the Bay's current problems, great as they may seem, are apt to the dwarfed by those at the end of the century. The Corps of Engineers predicts that the Bay area population will then be 12.5 million, an increase of 3.5 million from today. With more people will come more uses, and more users, more con- flicts , more dredging, more filling, and more wastes to be ac- commodated.

The establishment of the Chesapeake Bay Commission and the attention being given to the Bay and its problems by both the citizenry and officialdom gives reason for restrained' optimism.

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If the Commission fulfills its expectations and provides the leadership that is essential, it will bring citizens and local officials together to learn about and deal with the problems of the Bay. We may see on the Chesapeake a repudiation of the

c tragedy of the Common" theory and an adaption of "Save the Bay".

With these broad management problems in mind, the sponsors have planned and invited you to attend this conference on the effects of chlorine use in the Chesapeake. We hope it will contribute substantially to a better understanding of compli- cations that so frequently ensue when a problem is approached from a single direction.

A few years ago as the responsible official, I insisted that the Town of Concord, Massachusetts could empty its overflow sewage through a National Wildlife Refuge only if it installed facilities to treat that effluent with chlorine. Today, I would probably be just as insistent that the effluent be left' untreated. So, the sands of time run.on. We live, and hopefully learn, and do the best we can. We may not answer all the questions concerning the effects of chlorine on the Chesa- peake at this conference today, but we will illuminate the problems that attend its use, or disuse.

We welcome you, we appreciate your attendance, and we in- vite your full participation.

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MAJOR USES OF CHLORINATION (AN ECOLOGIST'S PERSPECTIVE)

William P. Davis

G B E R L EPA Cooperative Research Project

c/o Grice Marine Biological Laboratory 205 Fort Johnson

Charleston, S.C. 29412

The teirm "chlorine" is the popular term representing chlorination processes. Chlorination is the application of chlorine gas, or oxidative solutions of chlorine gas for the purpose of bleaching or disinfecting. This seems sublimely- simple to anyone familiar with common household cleansers like Clorox. However, what we must do here is think in a vastly scaled up fashion. Chlorination processes are the most ubiquitous use of a pesticide intended to kill micro-biological organisms. Furthermore, chlorination, like fire, is something we all have grown up with and taken for granted in our daily life patterns. Reassurances of the beneficial aspects of chlorination are everywhere,from assumed quality control of municipal drinking or swimming waters, to the assumed protection of natural waters receiving processed, domestically "used" waters. In this blissful acceptance we find another example where scientific research results at molecular and cellular levels trouble us as we look out at the vimmense scale of used water treatment in both treatment plants and industries (GAO Report, 1977).

The goal of municipal water treatment is to prevent spread of human pathogens, as well as to maintain quality of natural receiving waters. With the exception of treatment systems using hyperchlorination, chlorination application in municipal waste treatment occurs after process steps to digest organic wastes, themselves depending on bacterial action. Chlorination is used, therefore, as a prophylaxis to treat discharge waters. Chlorination in municipal treatment is applied by using "chlorine demand", setting application rates to produce a residual oxidant level. Overchlorination, therefore, can easily occur in response to high supply of wastewaters during floods, rain, plant mal- function/breakdowns, or just over-zealous controllers. In waste treatment plants, the crucial chlorination control point is the operator', .and the many pressures affecting, this person.

It has been repeatedly stated that chlorination is generally not effective in deactivating viruses. Ninety percent of pathogenic microbes are particle associated,and therefore go with the suspended particles which are filtered out of treated water. The performance of suspended particle removal helps one to judge

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and score the efficiency of municipal treatment plant operation. Chlorination does effect some viruses. Much remains unknown concerning the real nature of these effects or what true control we can accomplish upon viruses through chlorination.

Perhaps the most ironic point of U.S. water treatment technology is that chlorination destroys the principal indicator of plant efficiency, the bacterium Escherichia coli. In Britain chlorination is not ubiquitously applied and treatment plants are monitored by levels of occurrence and die-off rate of Escherichia coli in the receiving waters. In the United States we purge these data and therefore have less understanding of resistant viral and bacterial disinfection, as a result.

Within the Chesapeake Bay, electric power generators con- stitute another principal chlorination practitioner; because of efforts to control so-called biofouling, the growth of bacteria, invertebrate organisms within the plants' plumbing. Recently the asiatic clam Corbicula t has become an additional burden in freshwater plants. Power plants tend not to chlorinate during winter, but focus on spring and summer biofouling blooms. They are, therefore working very close to the dispersal time of larval stages of invertebrates and fishes.

Municipal treatment plants and drinking water treatment use about three to four percent of the annual chlorine production of the United States. George Clifford White summarizes (1978) the different uses of chlorination processes as follows (total U.S. figures):

Annual Production - about 10.5 million tons.

Uses : 1. Sanitary (Disinfection) Processes (potable water,

swimming pools, wastewater treatment, household use, food packaging.)

3-47o = 315,000-420,000 tons

2. Industrial Processes (including manufacturing of plastics). 80% = 814 million tons

3. Pulp and Paper Industry (bleaching and control of lignum sulfide odors).

16-177o = 1.68-1.785 million tons

These figures are useful to economists and longrange planners, but do they have much relevance to a specific ecosystem such as the Chesapeake--! suspect only in the most generalized sense. To understand better the impact of chlorination in a specific area I strongly recommend a finer focus on our "ecoscope". This will require us to visualize chlorination on several scales,

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as well as in terms of scientific and engineering disciplines. Chlorine gas, or a chlorine solution such as Clorox (sodium hypo.chlorite) is a powerful oxidizing agent. This means it is a very active ion in solution, powerful enough to disassociate less powerful salts and form chlorinated compounds. In any ecosystems with sea water influence, chlorine frees its halide cousin, bromine, from natural bromide salts and this bromine in turn becomes the active oxidant. This is relevant to our discussion, for as chloroform tends to concern specialists in. drinking water chemistry, bromoform is the principal by-product of chlorination of estuarine or marine waters. A few years ago we realized little to no data existed regarding the biological and ecological effects of bromoform. Bromoform forms at 200- 400 ppb with even low levels of chlorination, apparently by combination with naturally produced organics, such as mannitol, a by-product of algal cells (Crane, et al, 1980). It is classified as a mutagen, but we have found few effects upon fishes, molluscs or marine communities (Koenig, 1980). Bromo- form is only one of about 140-200 or more possible by-products from direct- chlorination of estuarine waters. Estuaries, exemplified by the Chesapeake, receive chemical components from fresh waters, marine waters, including numerous combinations, of man's chemical, agricultural, industrial and municipal activities. The less important question therefore, of how many specific by-products or compounds there are should be replaced by how much does the total system receive (Brush, 1974). This is truly a difficult problem.

There is in .any natural system, a demonstratable rate of degradation of compounds along with the input or supply rate. This degradation, or assimilative capacity of a system, is related to the presence of natural cycles, including sedimentation, microbial activities, and chemical processes such as chelation (Bourquin, 1978).

One of1the very disturbing findings of EPA granted research is the discovery that chlorination oxidation destroys the organo-metalic chelators (such as the humic/fulvic acids) which typically serve as the assimilative mechanism for such active metals as copper or zinc. Very simply, chlorination of coastal natural waters allows copper and zinc to become significantly more biologically available (Carpenter, et al, 1980).

You see, we already have gone from the major chlorine uses to several important impacts, yet we cannot predict the system limits, or suggest target levels for modulation or control. These kinds of data are discomforting and truly need concerted attention. Do they reflect inadequacy in our water quality criteria? My response to that is yes, but mainly because our present criteria do not truly scale up holistically to the levels of ecosystems. Additionally, changing conditions

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and rapid growth of populations versus our rather slow rate of improved scientific understanding, all serve to keep the issue complex. Chlorination uses, illustrate all humankind's frailties, needs, failures, and interacting complexities.

For the industrial or municipal treatment operations as well as power plant usages, we often hear: "Why not dechlorinate?" De-chlorination processes are basically deactivation of the oxidative power of the chlorine and bromine ions, using sulfur dioxide, sodium thiosulfate, or other related compounds. Our tests at Bear's Bluff using oysters exposed to low levels of chlorination and dechlorination resulted in inhibition to overall physiological condition index in flow-through experimental systems. These tests were run without entrained sewage, and the associated high stress from treated sewage bacteria. Furthermore after sixteen days of "depuration" oysters still did not return to the pretreatment levels of gonadal index. Excess thiosulfate also resulted in physiological stress in respiration and gonad condition in oysters.

Furthermore, to recall our discussions of chemistry, the chlorination by-products we briefly mentioned have already been formed, and are not affected by dechlorination processes. As a final caution, sodium thiosulfate is typically contaminated by metal salts, expecially in the grades one would purchase for mass application to effluents, adding still another problem. Dechlorination is probably not very justified for environmental protection except perhaps as an emergency response to a chlorine spill or massive escape, or, as in the case of small plants as a buffer when receiving waters are logistically immediately after treatment. Some research is needed to see if chelators can be restored along with dechlorination.

Alternative oxidative chemicals to chlorination are frequently suggested including bromochloride, ozone, and others. Other oxidative processes will generally free bromine from naturally occurring bromide salts the way chlorine did so, in fact, their added expense or control problems seems little justified in estuarine or marine waters. No, we will fret, but it remains a good bet that chlorination will continue, but yet, perhaps with more careful control.

Here are some of the problems to consider. Chlorination and oxidative by-products strongly and adversely effect larval fishes, oysters and crabs as well as their food, and associated natural productivity. It deactivates the natural complexing agents of copper and zinc making these metals more biologically available, sometimes with toxic effects. It forms hundreds of by-products, many of which are known to effect normal development (teratogens), cause genetic effects (mutagens), or cause cellular disfunction (carcinogens) in organisms.

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In this latter area the debate is fierce. In an holistic sense, however, chlorine is but one of a myriad of problems and its role in population expression of these adverse processes is not completely known. One must also consider that the municipal treatment plant receives thousands of suspect chemicals which potentially or actually become more dangerous to our health after they become chlorinated. Perhaps most disturbing is that chlorination applied without well managed waste pretreatment settling and removal processes encourages chemical combination of the chlorine and bromine with hydrocarbons to potentially produce by-products which can mimic or even out-perform the adverse effects that we associate with hard pesticides.

In the current public concern with genetic research and gene transfer, one is reminded of the extreme selection and evolutionary processes various bacteria undergo in nature to survive. So-called R-factors for increased resistence to environmental challenges do occur, and chlorination is as good a candidate for development of a resistant strain of a pathogen as any sloppy genetic DNA engineer. Bacteriologists know this response has already occurred with bacterial resistance to antibiotic drugs. What an ironic tragedy if we created resistent water-born disease organisms with our very efforts to control them; simply through overchlorination!

A popular Natipnal Public Radio/Public Broadcasting System program is the "Advocates in Brief" where lawyers, politicians, and theoreticians debate in legal-style the assets and adver- sities of some issue. Chlorination is a fine target for a public/scientific "advocates in brief". We use chlorination as commonly as we use fire. It has many of the same dangers and benefits. However, can we make a practical holistic model for guidance? Can we realistically modify our use patterns to retain, beneficial aspects? Will this be achieved before the Bay or other waters are burned out?

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REFERENCES

Bourquin, A1 W. and David T. Gibson. 1978. Microbial Degradation of Halogenated Hydrocarbons in: Water Chlorination, Environmental Impact and Health Effects. Vol. IV, R.L. Jolley, et al, eds. Ann Arbor Science Press, Ann Arbor, MI 48106.

Brush, Lucien M., Jr. 1974. Inventory of Sewage Treatment Plants for Chesapeake Bay. Chesapeake Research Consortium Pub- lication No. 28. Chesapeake Research Consortium Inc., Annapolis, MD 21403.

Burton, Dennis T. and L.B. Richardson. 1980. An Investigation of the Chemistry and Toxicity of Ozone-Produced Oxidants and Bromate to Selected Estuarine Species. Final Report for Research Assistance Grant R804683, Bears Bluff Environ- mental Research Laboratory, U.S. Environmental Protection Agency, Gulf Breeze, Florida 32561.

Carpenter, James H., Carroll A. Smith and Rodney G. Zika. 1980. Reaction Products from Chlorination of Sea Water in: Water Chlorination, Environmental Impact and Health Effects. Vol. Ill, R.L. Jolley, et^ al, eds., Ann Arbor Science Press, Ann Arbor, MI 48106.

Carpenter, James H., Carroll A. Smith and Rodney G. Zika. 1980. ' Reaction Products from the Chlorination of Sea Water. Final Report for Research Assistance Grant R803893, Bears Bluff Environmental Research Laboratory, U.S. Environmental Protection Agency, Gulf Breeze, Florida 32561.

Crane, Allan M., Stanton J. Erickson and Cynthia E. Hawkins. 1980. Contribution of Marine Algae to Trihalomethane Production if Chlorinated Estuarine Water. Estuarine and Coastal Marine Science 11:239-249.

Crane, A.M., P. Kovacic, and E.D. Kovacic. 1980. Volatile Halocarbon Production from the Chlorination of Marine Algal By-Products including D-Mannitol. Environ. Sci. and Tech. 14(11):1371-1374.

GAO Report CED-77-108. 1977. Unnecessary and Harmful Levels of Domestic Sewage Chlorination Should be Stopped. Re- port to the Congress by the Comptroller General of the United States. Washington, DC 48pp.

Koenig, Christopher C. and Claudia McLean. 1980. Rivulus marmoratus: A Unique Fish Useful in Chronic Marine Bioassays of Halogenated Organics in Water Chlorination. In: Water Chlorination, Environmental Impact and Health

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Effects. Vol. Ill, R.L. Jolley, et a^, eds. Ann Arbor Science Press, Ann Arbor, MI 48105T

Scott, Geoffery, and Douglas P. Middaugh, M.S., Effects of Chlorination and Dechlorination on the Growth;, Survival and Physiology of the American Oyster (Crassostrea virginica).

White, George Clifford. 1978. Current Chlorination and De- chlorination Practices in the Treatment of Potable Water, Wastewater and Cooling Water in: Water Chlorination, Environmental Impact and Health Effects. Vol. I, R.L. Jolley, ed. Ann Arbor Science Press, Ann Arbor, MI 48106.

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Discussion:

Q: The 80 and the 16, are they what winds up in the Bay, in the waters, or is that what's used?

Dr. Davis: That's out of the national production of chlorine gas, it doesn't mean that it gets in the Bay. It simply shows you the uses. It is not possible from the usage

to calculate .what actually gets in the receiving waters.

Q: Can you make a guess?

Dr. Davis: No. Each treatment plant has to be tailored to circumstances based on what's being shipped to it; it may get street runoff combined with domestic waste, or it may only deal with domestic waste. It's very difficult to extrapolate; you have to look at each plant separately.

Dr. Cronin: I'd underscore what Dr. Davis has said. When we tried to get information together on the Chesapeake and the use pattern, even the use quantities and rates and times of delivery are just extraordinarily difficult to assemble. There are some information pieces available but they have to be handled with great care.

Q: When you spoke of alternative forms of disinfection you mentioned^the two big drawbacks of expense and difficulty of operation. If a handle were gotten on those two factors, do you believe that these alternative forms would be beneficial, or would they still create further problems?

Dr. Davis: We have sponsored research to look at ozone compared to chlorination. When all the adjustments are made, if you add ozone you've added more oxygen to your system. Basically, I don't expect an alternative to be proposed for chlorination, at least where marine waters are concerned. I'm looking at it from the point of view of the effluent. I'm not looking at it from the point of view of drinking water. We would not predict different byproducts from the chlorination of marine waters in a power plant application from an alternative oxidant from the evidence now available.

Jerry Valiant: You spoke of dechlorination quite a number of times. Are you saying that organisms become acclimated to the chlorine, so that when you take it away by dechlorination there will be a depression among the organisms?

Dr. Davis: No, I don't think we've gotten anywhere near a level of research that would indicate something like that. When

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o

we use a combined response other than direct toxicity, dechlorination impacted on the health of an organism such as an oyster, less than chlorination, but certainly more than midway between chlorination and no chlorination. When we use sublethal organism responses like growth, we have to go in with a whole suite of tests because simply accelerated growth itself is not enough to evaluate its effect. There is another problem that I think is more important than the organism response, and that's that we've added another chemical and it's gtill under the same con- troller personnel that the chlorine is under. I think our chlorination problem basically is a control problem. Simply adding dechlorination as another step doesn't simplify the issue at all, it complexes it. Another concern is that a system which uses chlorination and dechlorination several times down the same river requires more chlorine at each treatment and more dechlorination after each treatment. I don't think the residual oxidant in the effluent of a plant is a good target anyway. There should be virtually none.

Q: Does part of it go back to the sewage treatment plant or is it dumped straight into the river?

Dr. Davis: We have been trying to get the different chlorination users to talk about their processing side and the other people studying the effluent to talk about that. We aren't happy with the numbers yet. We're talking about 80 percent of the national production going into bleaching and industrial uses. But, I don't claim to be enough of an industrial engineer to know how many of them actually end up in water effluents. I would suggest probably fairly few do, for the simple point of view that the regulators, us, are looking at the effluent levels and they could come out as salts and no longer be active oxidants. Basically what I was addressing here are those that come out as oxidants or organic complexes with the halite on it but not yet reduced down to the level of salt.

Dr. Helz: A lot of the industrially used chlorine ends up in polymers--like polyvinylchloride--vinyl plastics in your autos. Some of it is used in synthesizing solvents, like carbontetrachloride. Some of those solvents do end up in the environment, but they end up in a rather stable form, not in the oxidized form. So it's not fair to extrapolate from the four percent that industry... is putting back a large amount of strong oxidant. They are doing other things with much of that chlorine.

Dr. Cronin: In brief summary, a large percentage of the industrial use of chlorine and chlorine containing compounds ends up in forms which are not oxidative if they do get into the

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environment. The total use figures for industrial application cannot be directly used to estimate the quantity of oxidative chemicals in the receiving system.

Dr. Olivieri: Most of the 3 or 4 percent that is used in the water and wastewater plants will wind up as chloride, table salt. I think Jolly estimates that one percent of the chlorine applied in a sewage treatment plant winds up as chlorinated organics and a very small fraction will also wind up as combined forms of chlorine. So a very small amount of what get applied gets in. Most of it goes to chloride.

Del. Gerald Winegrad: You seem to have discounted the use of alternatives to chlorination, for instance bromine chloride and dechlorination. I'm wondering why, especially in light of the fact that you seem also to be saying that in areas such as the use of bromine chloride there haven't been enough studies done to indicate its potential impacts on bodies of water such as the Chesapeake Bay.

Dr. Davis: I didn't say there were not enough studies on bromine chloride, but I did throw caution on alternative oxidants. The reason for throwing caution on them is that management agencies can too easily be pushed into a technological fix. I feel more confident knowing the nature of the kind of fire I'm working with than trying to bring in new solutions for which we have very little background data. I think the first example of that was the work that we had done with ozone side by side with chlorination where all the information and the literature would lead us to believe that ozone was much less of a problem; but when we made the necessary adjustments, we found there was essentially no difference. It was just a matter of calibration. There is a difference if you're not talking about marine waters. So my remarks are directed more to the ecology of marine- eco systems. They do not necessarily apply in specific things like water treatment or other contained systems. In respect to bromine chloride, there has been an active debate on that. I have never had anyone show me that it is cheaper. It starts out about twice as much and you're paying for less active oxidant. There's a reason bromine chloride is readily available and that is that its original manufacture was for the manufacture of tetraethyl lead used in high octane gas. The reason we have a surplus bromine chloride capacity in the country is our changing usage patterns for gasoline. So these are the inner-linked kinds of things that I am skeptical about, and I think they should be carefully challenged before we decide to adapt them. Chlorine, we have a handle on.

Dr. Heyward Hamilton: I'd like to get a little discussion about the fact that we have a chlorination problem. If you set

Page 18

aside the uncertainties and the issues surrounding the treatment of drinking water and the formation of trihalomethanes and that whole complicated set of Questions and you think in terms of the other uses of chlorine, for power plant condenser treatment, for treatment of sewage, it s clear that with biological organisms we can detect the presence of residual oxidants at levels I believe well below what we can measure analytically. In that sense, there is a problem, and there is therefore something that needs research and needs concern. But, if you talk about chlorination as a problem in the sense that we have created, or are at risk of creating, contaminated food chains , that we are at risk of losing pro- ductive fisheries, then I get uncomfortable, because it is not clear to me that we know enough to say that that exists or that that is a problem.

Page 19

CHLORINE CHEMISTRY

George R. Helz

Department of Chemistry University of Maryland

College Park, MD 20742

Among the toxic chemicals that environmental managers discuss most, chlorine is fairly unique in that it undergoes extremely rapid chemical transformations. The CI2 molecule survives in water for only about one quarter of a second before being replaced with other chemical products which also are toxic. For this reason the impact of chlorination on aquatic organisms cannot be understood without first understanding chlorine's chemical behavior in water.

CONVERSION REACTIONS

A useful conceptual framework for discussing chlorine chemistry is provided by Figure 1. In the upper box is molecular chlorine, CI2, the starting point in most major chlorination systems. Some smaller systems begin with a dissolved hypochlorite such as NaOCl, familiar to many people as laundry bleach. Interaction of either starting material with water produces a mixture of H0C1 and 0C1 in less than one second. The ratio of H0C1 to 0C1 depends upon the water pH. In mildly acidic waters where H0C1 is dominant, chlorine is a much more efficient bacterial disinfectant than in alkaline waters where 0C1 predominates. This is thought to be related to the comparative case in which the uncharged H0C1 molecule can penetrate cell walls.

When seawater is chlorinated, as happens at many coastal power plants, the bromide (Br ) ions in the dissolved seasalt are rapidly oxidized, forming a mixture of HOBr and OBr" shown

upper right-hand box in Figure 1. Iodide ions behave in a similar fashion, but this reaction is of minor importance because of the low abundance of iodide.

Figure 2 shows the theoretical abundances of chlorine- produced oxidants when water is chlorinated to a level of 5 mg/1. Freshwater has a salinity effectively of zero, and normal ocean water has a salinity of about 35 g/kg; intermediate values are found in estuaries. When the salinity exceeds only a few grams per kilogram, the bromine compounds entirely replace the chlorine compounds. In this process, the chlorine by-products are reduced to stable chloride (Cl") ions which enter the large reservoir of chloride naturally present in

Page 20

Most Important in Freshwater Most Important in Seawater

i r

Figure 1. Schematic outline of chlorine reaction pathways

seawater. Under typical treatment conditions at estuarine power plants, this reaction might reach completion in ten or twenty seconds. Although the chlorine-containing toxic compounds may entirely disappear as a result of this process, the disinfection capacity of the water is not destroyed because HOBr and OBr" are aggressive biocides like HOC1 and OC1 .

Ammonia and organic amines, including amino acids which are constituents of proteins, react rapidly in the presence of H0C1, 0C1~, HOBr or OBr" to form a group of halamines:

Inorganic Organic

NH2C1 NH2Br

NHC12 NHBr2

NCI3 NBr3

NRHC1 NRHBr

NR2C1 NR2Br

MRC12 NRBr2

Page 21

Like their chemical parents, these halamines are toxic, although frequently less so than their parents. For instance, bottles of laundry bleach always carry a warning not to mix bleach with household ammonia because certain halamines, especially NCI3 and NBrg, are volatile and very poisonous.

10 20 30 SALINITY (G/KG)

Figure 2. Variation in abundances of chemical species at equilibrium in estuarine water. Assumed conditions Temp = 250C, pH = 7.5'; Total ammonia = 0.01 mg/1.

The halamines form relatively rapidly", although several minutes may be required under normal treatment conditions for the reactions to become complete. Treatment of drinking waters usually involves addition of chlorine well in excess of the available ammonia and amino-nitrogen so that excess H0C1 and 0C1~ remain after halamine formation is complete. In contrast, the high ammonia and amino-nitrogen content of sewage treatment plant effluents may consume all the H0C1 and 0C1" during formation of halamines. The wide range of water qualities found at power plants leads to a wide range of chlorine by-product mixes

The reactions discussed thus far lead to dozens of potentially significant chlorine by-products, all of which are toxic to varying degrees, and all of which form in a relatively

Page 22

short time period after chlorine treatment. The exact mixture of by-products that will be produced in any specific instance depends upon a number of variables: temperature, chlorine dose, pH, salinity, ammonia concentration, and the nature and concentration or organic amines. The multiplicity of controlling variables^creates a severe challenge in the design of good toxicological experiments involving natural waters or sewage treatment plant effluents.

CHLORINE ANALYSIS

Since the CI2 molecule survives less than a second in water, it is distressing to some people to learn that chlorine can be measured in water for hours or days after treatment. What is being measured, of course, is the mixture of oxidative by-products mentioned in the last section. The standard analytical methods are incapable of identifying the individual molecular species, but instead measure the oxidizing capacity of groups of species. By convention, the results of such analyses are expressed in terms of the chlorine concentration which would provide an equivalent oxidizing capacity.

Ideally, with appropriate analytical manipulationi it is possible to separate the chlorine by-products into two groups: the HOCl-OCl~-HOBr-OBr~ group which is usually called free chlorine or free oxidant, and the halamine group which is • usually called combined chlorine or combined oxidant. These designations are indicated on the right side of Figure 1. Total chlorine or total oxidant is the sum of these two groups. Un- fortunately this group separation is rarely, if ever, perfect.

A great deal of research has been done to find analytical methods for free chlorine which measure only the free fraction, truly and exclusively; but problems persist, especially in the analysis of chlorinated seawater. It is important to recognize that virtually all of the analytical methods for chlorine and its by-products actually measure oxidizing capacity, not toxicity, in the water. A given concentration of free chlorine, for example, can vary by 100-fold in its toxicity depending on which chemical species are actually present. Some interesting advances have been made at the University of North Carolina in recent years toward finding rapid analytical methods which will provide measures of toxicity, but much remains to be done.

Despite a great deal of research on analytical methods for chlorine by-products, problems associated with analyses remain a serious impediment to regulation and control of chlorine in the environment. Detailing the deficiencies in analytical methods would be beyond the scope of this paper, but considerable improvement needs to be made in the accuracy at low levels and in the specificity for individual molecular

Page 23

products or groups of products. Standard procedures for certifying laboratories also need to be developed.

NON-OXIDATIVE PRODUCTS

The free and combined oxidants generated by chlorination gradually decline in concentration with time and eventually disappear. Although chlorine has been used extensively for disinfection since the 1930's, interest in the chemical reactions responsible for the disappearance of chlorine has arisen only in the last seven or eight years. This interest was sparked by the discovery that halocarbon compounds are produced by chlorination of drinking waters and sewage treatment plant effluents. Halocarbons in general exist much longer in the environment than the oxidative by-products of chlorine. Some bad experiences with certain halocarbons, such as DDT and the PCBs, raised fears initially that the halocarbon by-products of chlorination might present a major threat to public health. The initial fears have subsided considerably, however, because recent results from a number of laboratories indicate that halocarbons are a minor product of chlorination and that only a few percent of the chlorine used in water treatment is employed in making halocarbons. Further, none of the halocarbons so far shown to be chlorine by-products has proven to be a really potent toxicant.

One class of halocarbons, the trihalbmethanes, are virtually ubiquitous products of drinking water chlorination in this country and abroad. Six individual trihalomethanes are commonly observed, although chloroform, CHClo, usually predominates. In chlorinated seawater, on the other hand, CHBrg is usually predominant as indicated in Figure 3. ' (Notice the close corres- pondence between Figures 2 and 3.) The production of trihalomethanes is sharply curtailed in waters where free oxidants are rapidly consumed, for example by reaction with high concentrations of ammonia or amino-nitrogen. Thus production of trihalomethanes is usually modest in sewage treatment plant effluents or in drinking water or seawater that has been modified by addition of high concentrations of ammonia. Un- fortunately, chloroform appears to be carcinogenic in mice and rats.

For the most part, few halocarbons other than trihalomethanes are generated when clean natural waters are chlorinated at levels normally used for drinking waters or power plant cooling waters. Most of the chlorine is^consumed in reactions which produce other products. As yet these products are not known with much certainty or completeness, a somewhat disturbing situation. Some of the products are unquestionably innocuous, such as N2 and CO2, but the biologic or health effects of others, such as bromate in seawater and organic oxidation products, are uncertain.

Page 24

iooi-

80 /

o 14 DOSE

• 140 jjM DOSE - 40

CD 20

00 5 10 15 20 25 30 35

SALINITY (g/kg)

Figure 3. Br as a percent of Cl+Br in the trihalomethanes (CHCl-j, CHCI2, Br, CHClBr2 and CHBr3) produced by chlorinating natural estuarin^ water. Dose refers to the amount of chlorine added; 14 pM corresponds to 1 ppm CI2 and 140 yM corresponds to 10 ppm CI2. These doses bracket values typically used at power plants.

CHLORINE ALTERNATIVES

Concern about both the health effects of halocarbons in drinking water and the ecosystem impacts of discharges from sewage treatment and power plants has generated public pressure on environmental managers to do something about chlorine. One option with many advocates is to replace chlorine with another disinfectant such as O3 or BrCl. As a chemist, I have an intuitive skepticism about the ultimate benefits of this course of action. Fast-acting broad spectrum disinfectants for the most part are aggressive chemicals, like chlorine. They can be expected to react with components of natural waters and wastewaters in numerous and sometimes unexpected ways. In the case of seawater treatment, alternate oxidative biocides, such as O3 and BrCl, generate HOBr just as chlorine does, so similar yields of bromocarbons, bromate and other products must be anticipated regardless of which compound is used. In my view, a wiser course of action is to retain the use of chlorine, about which we now know so much, but to pursue a policy of minimizing its use wherever practicable.

Page 25

ACKNOWLEDGEMENT

I would like to take this opportunity to thank the Maryland Power Plant Siting Program which was willing to sponsor some of my research on chlorine well before the subject had become fashionable. I am also grateful to other research sponsors, the U.S. Environmental Protection Agency and the Electric Power Research Institute, and to my students who have provided continued intellectual stimulation.

REFERENCES

Hall, L.W. Jr., G.R. Helz and D.T. Burton. 1981 POWER PLANT CHLORINATION - A. BIOLOGICAL AND CHEMICAL ASSESSMENT. Ann Arbor Science Publishers.

Jolley, R.L. et. al., editors. 1978 and 1980. WATER CHLORI- NATION - ENVIRONMENTAL IMPACT AND HEALTH EFFECTS, Volumes 1-3. Ann Arbor Science Publishers.

Safe Drinking Water Committee. 1980. DRINKING WATER AND HEALTH, Volume 2. U.S. National Academy of Sciences.

White, G.C., 1972. HANDBOOK OF CHLORINATION. Van Nostrand Reinhold Co.

Page 26

Discussion:

Nancy Kelly: Have you looked at retention ponds for power plants as a possible way of reducing chlorine toxicity to the environment and if so what kinds of chemical changes would occur in those retention ponds that would perhaps make the chlorine that left those less toxic.

Dr. Helz: We have not looked at that in a detailed way, at least not in the field. We have done experiments at the Chalk Point Plant where we have looked at the concentration as the water flows down the cooling canal. As you may know, that canal is about two to two and a half kilometers long, it is unusually long. So, to some extent that might model

•a.cooling pond. Chlorine continues to decay. At Chalk Point, the amount that emerged into the Patuxent was extremely small, not uncommonly ten parts per billion which is down in the level where many people could not measure d.t. If .1 understood the latter part of your question,

; you were concerned about the possibility that if we created holding ponds so that, the effluent was held up before it got discharged into the environment, "would we end up with

i --perhaps different products than otherwise?" You couldn't answer that in an absolute universal way, because it would depend very much on what chemical species were in the water. If you have an effluent that has predominantly halogenated amino compounds in it, which probably applies to many sewage treatment plants, then it is unlikely that whether you discharge that immediately or hold it up, you will have any effect on the ultimate products. Those products are already chemically far enough down the cascade, the chemical cascade, that they are comparatively unreactive. They are ultimately going to decay to other things, and they are oxidants, so I would not want to say that they are unreactive, but they are not the very aggressive chemicals, that the free chlorine would be. The answer depends very much on the specific site and the specific chemistry that you are dealing with.

Ms. Kelly: I would like you to comment on the chemical results of ultraviolet treatment and if they are similar to the ozonation and chlorination.

Dr. Helz: The ultraviolet radiation of water and gamma ray radiolysis of water also produces lots of free radicals and these will produce different kinds of compounds in general than one gets from chlorination, but not necessarily different compounds than one gets from ozonation. Ozone has two general styles of reaction with components of natural waters. One involves the ozone molecule itself attacking a substrate, perhaps an organic olefin,and one gets direct

Page 27

reactions of the ozone molecule. The other style of ozone interaction with water involves decay of ozone by reaction with hydroxide ions in solution and this produces free radicals very similar to the process of photolysis. This second process becomes increasingly significant as the pH of the water goes up, again we get back to having to discuss these things in the context of a specific water and specific species, because the composition of the water is very important. I could forsee some of the kinds of products that one gets from ozonation being very similar to those that one would get from photolysis. A very good example involves some work that I was involved with the Johns Hopkins group where we looked at the production of bromide by photolysis of sea water that had been chlorinated and by ozonation of sea water in the absence of light. One can argue that the mechanism is very much the same. You get bromide either by ozonation or by fertilizing sea water and so this is one example where a similar product results from those two different processes.

Q: Could you comment on membrane probes?

Dr. Helz: The membrane probes were developed by Donald Johnson at the University of North Carolina, specifically to get at this problem of finding a better way of measuring toxicity rather than oxidizing capacity. One has to have a great deal of sympathy with Johnson in otfder to believe that this really measures toxicity, but it does a lot better than the other methods available, because it selects against ionic materials which, at least in bacterial disinfection, seem to be less toxic than the free. I believe Dr. Olivieri has shown that in the case of viral toxicity the hypochloride is more effective.

Dr. Olivieri: I would like to comment on Johnson's membrane. We have done some work with the membrane itself and it does indeed respond to free chlorine. It does also respond to monochlorine. There is some problem with selectivity, but sensitivity is high. The other problem is that it's very sensitive to nitrogen trichloride or trichloramine. It's more sensitive to trichloramine than it is.to chlorine and/ or monochlorine. Like any of the methods for measuring chlorine, you have to understand the test, and there's no magic way to take the measurements. You have to understand what you're doing in order to interpret the results.

Page 28

ACUTE TOXICITY POTENTIAL OF CHLORINATION IN ESTUARINE'WATERS*

Morris H. Roberts, Jr.

Virginia Institute of Marine Science and School of Marine Science College of William and Mary

Gloucester Point, Virginia 23062

Two, primary uses of chlorination ■ in estuarine systems are disinfection.of sewage effluent and fouling control in conden- sor tubes of electric power generating plants. The intent in both uses is to apply sufficient chlorine to kill certain target organisms.' At the same time, however, efforts are made to control both the application rate and effluent release so that non-target species in the receiving waters are not affected. To accomplish such control, the effluent is usually retained, which permits the decay of the residual chlorine and rapid dilution with ambient water to reduce further the residual. The residual concentration continues to decay in the ambient water through a series of reactions outlined in Dr. Helz's paper. If all goes well, no adverse impacts can be expected in the receiving waters.

However, at least two disquieting instances of chlorination1s possible impact in the Chesapeake Bay have been observed. First,

:in 1966 a significant depression in primary production was noted in the effluent. mixing zone of the Chalk Point power plant in Maryland, especially during periods of chlorination (Morgan and,Stress, 1969; Hamilton et al., 1970). The second obser- vation was a massive fish kill in the lower James River during the spring of 1974. A series of quickly developed tests strongly implicated chlorination at a sewage treatment plant as the principal cause (Bellanca and Bailey, 1977). These observations and ones elsewhere stimulated extensive research in the 1970's into the effects of chlorination. This paper addresses such observed acute effects.

Acutely toxic concentrations (LC 50s) are, by definition, those concentrations which cause the death of fifty percent of a population of aquatic organisms in a specified time span, ranging.from moments to hours to a few days. Early researchers studying the effects of chlorination selected methodologies and test durations which suited their specific environmental concerns. For example, testing the effects of chlorination on

^Contribution No. 1002 from the Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, Va. 23062.

Page 29

organisms contained in cooling water passing through a power plant requires only a few minutes exposure to high chlorine concentrations and high temperature. On the other hand, testing the effects of chlorinated sewage on organisms in receiving water requires prolonged exposure of several days. Additionally, the experimental design should include treated sewage because sewage affects the chemical species present to which the organisms are responding.

The acute effects of chlorine on various estuarine animals are summarized in "Figure 1". Rather than including every data point available, this figure presents only recent data to determine whether results of these studies change general conclusions about chlorination's effects. Further data is contained in Mattice and Zittel's (1976) excellent paper summarizing data through about 1974.

10.0-

i.o-

o CE

o in

0.1

0.01 ■ 10

A

A

• FISH A CRUSTACEAN o BIVALVE

o

A

• 8 o o

A

~H ■ «—'—i i i i 11—•—i ^—i—i i i i i | 100 1000 10,000

TIME (minutes)

n 1 1—i- 100,000

Figure 1. Summary of Acute Toxicity of Total Chlorine Residuals to Estuarine Fishes, Crustacea and Mollusks Independent of Life Stage.

Page 30

Several things are apparent in Figure 1. Clearly, bivalves are generally more sensitive to chlorine residuals than either fishes or crustaceans. Life stages are not distinguished in this figure, but almost all data points for bivalves were obtained using embryos or larval stages. For fishes and crustaceans data are shown in this figure for larval and adults. Second, the LC50 is higher for short exposures than long exposures since both time and concentration play a role in the acute response of an organism to a toxic substance. From a practical standpoint, however, the operator of a power plant- which produces high chlorine residuals for only brief periods might apply chlorine at somewhat higher rates than the operator of a sewage plant in which chlorination is continuous. Third, if the exposure lasts two to eight days, most organisms tested can tolerate a concentration of 0.02 mg/1, which agrees with the conclusion of Mattice and Zittel (1976). In one test on striped bass (Morone saxatilis) eggs, the 48 hour LC50 was approximately 0.01 mg/1. Similarly, the 48 hour LC50 for coot clam (Mulinia lateralis) embryos ranged between 0.01 and 0.1 mg/1 in different larval batches. Thus the 0.02 mg/1 concentration which Mattice suggested as an upper limit for chlorine in saline water does not totally protect against acute toxicity.

To place these values in perspective, some knowledge of the chlorine concentrations actually produced in ambient waters is needed. For example, during the 1974 fish kill in the James River, two samples were found to contain 2.0 mg/1 and. several others contained more than 0.2 mg/1. When the chlorination rate was reduced, ambient levels declined below detectable limits as the fish kills ceased. Today at the same plant, it is extremely rare to observe even 0.01-0.02 mg/1 except in the immediate vicinity of the outfall. Thus, proper management at this plant has greatly reduced the potential for producing acutely toxic residuals. In waters receiving power plant effluents, reported residuals are generally below 0.01-0.02 mg/1 (Fox and Moyer, 1975), which is the approximate limit detectable by most field methods. These findings suggest that, given present practice, the residuals that can be expected in the environment are below but close to levels which are acutely toxic to the most sensitive species.

Early life stages are generally more sensitive to toxicants than juveniles or adults. The 48 four LC50 for oyster embryos (two to six hours after fertilization) was 0.025 mg/1 (Roberts & Gleeson, 1978), whereas the 48 hour LC50 for straight hinge larvae was 0.3 mg/1 (Rooseburg et al., 1980). Prediveligers are even more tolerant; extrapolating the data of Roosenburg and his colleagues, this later stage has a 48 hour LC50 of perhaps 0.5 mg/1. Adult oysters exhibit reduced shell growth when exposed to chlorine at concentrations of only 0.023 mg/1 (Roberts and Gleeson, 1978), but do not die when exposed to concentrations as high as 0.5-1.0 mg/1 even after 96 hours. Similar relation-

Page 31

ships between life stage and sensitivity to chlorine can be shown for fishes and crustaceans.

Dechlorination, the chemical reduction of chlorine residuals with a suitable reducing agent, can eliminate the acutely lethal effects of chlorine on both freshwater and estuarine species (Esvelt et al., 1973; Ward et al., 1977; Roberts, 1980). One study showed that chlorination followed by dechlorination actually reduced toxicity below that of unchlorinated effluent (Esvelt et al., 1973). In addition, a moderate excess of the reducing agents has no demonstrable adverse effect on those species tested to date. Dechlorination has been recommended at new sewage treatment plants in Tidewater Virginia to reduce the possibility of acutely adverse effects of chlorination, should present management control measures fail (Douglas, 1979).

In all of the studies reviewed for this paper, there is great uncertainty about the exact chemical species causing the observed responses. Thus, the mix of active chemicals which probably was not the same in all studies, may contribute to the variability in response shown in Figure 1.

Various halogenated organic compounds have been observed to be formed by chlorination of either sewage or natural waters (Jolley, 1973; Jolley, 1974; Glaze and Henderson, 1975; Jenkins et al., 1978; Rook, 1974). The most ubiquitousorganohalogens which appeared in the highest concentrations in the effluent of a Virginia sewage treatment plant were the trihalomethanes, chloroform or bromoform (Roberts et al., 1980). Concentrations up to 0.6 ug/1 chloroform and 7.2 ug/l bromoform have been reported in the vicinity of both power plant and sewage effluents in Virginia and Maryland (Bieri et al., 1980). These are compounds known to be hazardous in some environments. At present, however, there is limited data on the acute effects of these compounds on freshwater animals and apparently no data for estuarine animals. Therefore, it is impossible to fairly assess the potential environmental significance of the observed concentrations of haloforms or to evaluate the need for time- consuming and expensive studies of chronic effects.

In summary, chlorine residuals are toxic when present in sufficient concentration. Present chlorination practices produce residuals approximating the acutely toxic concentration, especially for early life history stages. The technology is available, however, to remove the chlorine residual from effluents, thus reducing or eliminating the potential for acute lethal effects.

Page 32

REFERENCES

Academy of Natural Sciences of Philadelphia. 1970, Chlorine and thermal Bioassay Studies of some marine organisms for the Potomac Electric Power Company, Final Report. 14 pp. and 8 Figures.

Bellanca, M.A. and D.S. Bailey. 1977. Effects of chlorinated effluents on the aquatic ecosystems of the lower James River. J. Water Pollut. Control Fed. 49:639-645.

Bieri, R.H., M.K. Cueman, R.J. Huggett, W. Maclntyre, P. Shou, C.L. Smith, C.W. Su and G. Ho. 1980. Toxic Organic compounds in the Chesapeake Bay. Report to Environmental' Protection Agency for Grant No. R806bl2010, 23 pp.

Burton, D.T., L.W. Hall, Jr., S.L. Margrey, and R.D. Small. 1979. Interactions of chlorine, temperature change (AT) and exposure time on survival of striped bass (Morone saxatilis) eggs and larvae. J. Fish. Res. Bd. Canada 36:1108-1113. '

Capuzzo, J.M., J.A. Davidson, S.A. Lawrence and M. Libni. 1977. The differential effects of free and combined chlorine on juvenile marine fish. Estuarine Coastal Mar. Sci. 5:733-741.

Capuzzo, J.N., S.A. Lawrence, and J.A. Davidson. 1976. Com- bined toxicity of free chlorine, chloramine and temperature to stage I larvae of the American lobster Homarus americanus. Water Res. 10:1093-1099.

Douglas, J.E., Jr. 1979. Summary Report of the Select Inter- Agency Task Force on Chlorine. Virginia Marine Resources, Commission, 8 pp.

Esvelt, L.A., W.J. Kaufman, and R.E. Selleck. 1973. Toxicity assessment of treated municipal waste waters. J. Water Pollut. Control Fed. 45:1558-1572.

Fox, J.L. and M.S. Moyer. 1975. Effect of power plant chlorination on estuarine productivity. Chesapeake Sci. 16:66-68.

Glaze, W.H. and J.E. Henderson, IV. 1975. Formation of organochlorine compounds from the chlorination of a municipal secondary effluent. J. Water Poll. Control Fed. 47:2511- 2515.

Hamilton, D.H. Jr., D.A. Flemer, C.W. Keefe, and J.A. Mihursky.

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1970. Power plants: effects of chlorination on estuarine primary production. Science, 169:197-198.

Heinle, D.R. and M.S. Beaven. 1977. Effects of chlorine on the copepod Acartia tonsa. In: Proc. Chlorination Workshop Block, R.M. and G.R. Helz (ed.). Chesapeake Sci. 18(1)- 140.

Heinle, D.R. and M.S. Beaven. 1980. Toxicity of chlorine- produced oxidants to estuarine copepods, pp. 109-130. In: A.L. Buikema, Jr. and J. Cairnes, Jr. (Eds.) Aquatic Invertebrate Bioassays, ASTM, STP No. 715.

Jenkins, R.L.^J.E. Haskins, L.G. Carmona and R.B. Baird. 1978. Chlorination of benzidine and other aromatic amines in aqueous environments. Arch. Environm. Contam. Toxicol 7:301-315.

Jolley, R.L. 1973. Chlorination effects on organic constitutents in effluents from domestic sanitary sewage plants. Ph.D. Dissertation, Univ. Tennessee, 339 p. ORNL-TM-4290.

Jolley, R.L. 1974. Determination of chlorine-containing organics in chlorinated sewage effluents by coupled 36C1 tracer-- high resolution chromatography. Environ. Letters 7:321- 340.

Laird, C.E. and M.H. Roberts, Jr. 1980. Effects of chlorinated seawater on the blue crab Callinectes sapidus, pp. 569-579. In: R.L. Jolley, W.A. Brungs and R.B. Cummings (Eds.), Water Chlorination. Environmental Impact and Health Effects, Vol. 3. Ann Arbor Science Press Inc., Ann Arbor, MI.

LeBlanc, N.E., M.H. Roberts, Jr., and D.R. Wheeler. 1978. Disinfection efficiency and relative toxicity of chlorine and bromine chloride--A pilot plant study in an estuarine environment. Final report to the S.E. Coastal Plains Region Commission prepared under the auspices of the Virginia Interagency Task Force on Chlorine, 55 pp. (in manuscript).

Liden, L.H., D.T. Burton, L.H. Bongers andA.F. Holland. 1980. Effects of chlorobrominated and chlorinated cooling waters on estuarine organisms. J. Water Pollut. Contr. Fed. 52- 173-182.

âttice, J.S. and H.E. Zittel. 1976. Site-specified evaluation of power plant chlorination. J. Water Pollut. Contr. Fed 48:2284-2308.

Middaugh, D.P., J.A. Couch, and A.M. Crane. 1977. Responses

Page 34

of early life history stages of the striped bass, Morone saxatilis, to chlorine. Chesapeake Sci. 18, 141-153.

Middaugh, D.P., A.M. Crane, and J.A. Couch. 1977. Toxicity of chlorine to juvenile spot. Leiostomus xanthurus. Water Res. 11:1089-1096.

Morgan, R.P.,II and R.D. Prince. 1978. Chlorine effects on larval development of striped bass (Morone saxatilis), white perch (M. americana) and blue-back herring (Alosa aestivalis). Trans. Am. Fish. Soc. 107(4):636-641.

Morgan, R.P., II and R.G. Stress. 1969. Destruction of phytoplankton in the cooling water supply of a steam electric station. Chesapeake Sci. 10:165-171.

Roberts, M.H., Jr. 1980a. Survival of juvenile spot (Leiostomus xanthurus) exposed to bromochlorinated and chlorinated sewage in estuarine waters. Mar. Environm. Res. 3:63-80.

Roberts, M.H., Jr. 1980b. Detoxification of chlorinated sewage effluent by dechlorination in estuarine waters. Estuaries 3:184-191.

Roberts, M.H., Jr. and R.H. Gleeson. 1978. Acute toxicity of bromochlorinated seawater to selected estuarine species with a comparison to chlorinated seawater toxicity. Mar. Environ. Res. 1:19-30.

Roberts, M.H., Jr., C.E. Laird and J.P. Illowsky. 1979. Effects of chlorinated seawater on decapod crustaceans and Mulinia larvae. U.S. EPA, Gulf Breeze Environmental Research Laboratory, EPA 600/3-79-031, 110 pp.

Roberts, M.H., Jr., R.J. Diaz, M.E. Bender, and R.J. Huggett. 1975. Acute toxicity of chlorine to selected estuarine species. J. Fish. Res. Board, Can. 32:2525-2528.

Roberts, M.H., Jr., N.E. LeBlanc, D.R. Wheeler, N.E. Lee, J.E. Thompson, and R.L. Jolley. 1980. Production of Halogenated Organics During Wastewater Disinfection. Va. Inst. Mar. Sci., SRAMSOE No. 239, 48 pp.

Rook, J.J. 1974. Formation of haloforms during chlorination of natural waters. Water Treatment Exam. 23:234-243.

Roosenburg, W.H., J.C. Rhoderick, R.M. Block, V.S.Kennedy, S.R. Gullans, S.M. Vreenegoor, A. Rosenkranz and C. Collette. 1980. Effects of chlorine-produced oxidants on survival of larvae of the oyster Crassostrea virginica. Mar. Ecol.

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Prog. Ser. 3:93-96.

Ward, R.W., R.D. Giffin, and G.M. DeGraeve. 1977. Disinfection efficiency and residual toxicity of several wastewater disinfectants. Vol. II. Wyoming, Michigan. Environmental Protection Technology Series, EPA-600/2-77-208, U.S. EPA, Cincinnati, Ohio, 107 pp.

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SUBLETHAL EFFECTS OF CHLORINE-PRODUCED OXIDANTS ON ESTUARINE ORGANISMS

Chae Laird

Continental Shelf Associates Tequesta, Florida 33458

Abstract

Sublethal effects of chlorine-produced oxidants (CPO) have been demonstrated for several estuarine species, primarily fish and invertebrates. These effects are manifested as alterations of development, growth, reproduction, general behavior and a wide variety of specific physiological functions, all of which may differ among species. Typical sublethal physiological responses to CPO in fish and invertebrates reflect disruption of respiration, osmoregulation and/or ion regulation (probable mechanisms of lethal effects). Other sublethal responses to CPO include abnormal development (e.g. scoliosis and eye malformations in fish), inhibited reproduction, retarded growth and avoidance behavior. For many species these responses have been recorded only at CPO levels approaching lethal levels.

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THE ASSOCIATION OF CHLORINE IN DESTROYING THE AQUATIC

UPPER HALF OF THE

POLLUTION AND OVERGRAZING PLANT COMMUNITY OF THE POTOMAC ESTUARY

Horace V. Wester

Principal Plant Pathologist National Park Service

National Capital Region

Abstract

There is ample documentation that the upper Potomac estuary was still a very healthy ecosystem with abundant stands of wild rice and dense meadows of submerged aquatic plants well into the 1930s. Since then the extent of the submerged aquatic plant community has been significantly reduced and virtually extirpated from the shallows of the Potomac from Washington, D.C. to the George Washington Birthplace National Monument on Popes Creek, Virginia. Emergent plants, such as wild rice, have suffered a similar fate in the Metropolitan Washington area, but have been less affected in the estuarine area studies south of this area.

Chlorine is a very effective biocide that is commonly used to control biological activity in water. Electric power generating facilities that use water for steam generation or as a coolant often chlorinate water passing through algae and fungi. Sewage treatment facilities use chlorine as a disinfectant in their effluent. The biocidal effect of chlorine is broad and non-selective; and its persistence in water that flows from municipal and industrial plants continues the lethal effect on sensitive biota. Chlorine in discharge water will affect the food chain by elimination of primary producers and ultimately causes major secondary effects that begin with this initial disruption.

In 1976 Wester and Rawles identified an association between increased chlorination and feeding of estuarine wildlife with severe ecological disruption in the upper half of the Potomac estuary. The increase in chlorine levels in the Potomac were coincident with the increase in discharge from two facilities on opposite banks of the river: one a sewage treatment plant, the other an electrical power generating plant.

Chlorine has the effect of reducing the vigor and abundance of submerged aquatic vegetation. Zizania aquatica (wild rice) is subject to the ecologically disruptive effects

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of chlorine only in the fragile submerged aquatic seedling stage. Once it achieves emergence it continues expected growth seemingly nonaffected by chlorine in the water surrounding it. Plants that remain submerged throughout their entire life cycle, such as Egeteria densa and Potomogeton crispus, suffer further devastation caused by overgrazing. This increase in overgrazing on submerged aquatic plants has caused reduction in the estuarine plant community that extends well beyond the limits to which the biocidal effect of chlorine persists in the water of the Potomac.

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ON THE RISKS

Victor Cabelli

Department of Microbiology University of Rhode Island

Abstract

The results from a series of prospective epidemiological- microbiological studies sponsored or conducted by the U.S. Environmental Protection Agency to develop recreational water quality criteria provide some insights as to the need for disinfection of municipal wastewaters. A major output from the studies was a regression equation relating the rate of swimming-associated gastroenteritis to the mean enterococcus density in the bathing water. Gastroenteritis was the only illness (reported as symptoms) which was both swimming associated and pollution related; and, of the microbial indicators examined (including total coliforms, so-called fecal coliforms and Escherichia coli), enterococcus densities in the bathing water were the best correlated to the swimining-assbciated gastroenteritis rates.

The regression equation shows that swimming-associated gastroenteritis rates of about 10 per 1000 swimmers was associated with mean enterococcus densities in the water of about 10 per 100 ml. The enterococcus densities in primary and secondary treated sewage were 5.31 and 3.94 orders of magnitude, respectively as determined from a study conducted at nine sewage treatment plants in Rhode Island. Thus, in order to achieve the stated level of risk, reductions in the enterococcus densities of about 4 and 3 orders of magnitude, respectively, would need to be achieved by the combination of'initial dilution and subsequent reductions due to physical and biological decay during transport of the wastewater between the source (outfall) and potential targets (bathing beaches and shellfish-growing areas). The former (a 4 log reduction) is readily achievable without recourse to disinfection from long, deep coastal outfalls such as those along the Pacific Coast; and infrequently obtainable along the Atlantic Coast because of the long continental shelf and the estuarine location of many cities. The latter (a 3 log reduction) is obtainable, at times, along the Atlantic Coast. More important, this analysis points out the need to consider the requirement for disinfection on a case by case basis with regard to the local situation; and this is precisely the position taken by the USEPA in 1975.

There is yet another alternative to disinfection; it

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is the acceptance of a greater risk of swimming-associated gastroenteritis, although one would be loathe to accept elevated risk levels of more serious diseases such as infectious hepatitis and typhoid fever. This alternative is consistent with risk analysis; and the costs of treatment and disinfection and untoward ecological effects are legitimate inputs in determining the acceptability of risk. However, speaking for Homo sapiens, it would seem unjust to ask this species to appreciably increase its risk of infectious disease in order to make untoward environmental effects "risk-free". That is, some reasonable balance must be achieved — on a case by case basis.

It is unlikely that the measures required to maintain an acceptable risk of shellfish-borne disease will be any less than those required for swimming-associated illness since the existing USEPA fecal coliform limits for the former are about one order of magnitude less that those for the latter. Furthermore, as seen from -the available epidemiological information, the most "important" and/or prevalent water-related infectious diseases are infectious hepatitis and acute gastroenteritis. The etiological agent of the former is a virus, and the Norwalk-like viruses have increasingly been shown to be the agent of the latter disease. It is now clear that more rather than less rigorous "disinfection" will be required to reduce the levels of these pathogens to acceptable levels. Finally, it is the contention of some workers in the field that chlorination, at least, is ineffective in disinfecting municipal wastewaters of viral agents. Other investigators contend that properly conducted chlorination of adequately treated wastewater effluents is effective against viral agents. At least a part of this controversy has its roots in semantics.. Disinfection, like pregnancy, is an absolute; and, to this author's knowledge, the absolute destruction of every pathogenic cell and virion in an infinite quantity of sewage effluent never was a reasonable expectation of wastewater "disinfection".

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THE EPA POSITION

Allan Rubin

Water Criteria Section n U.S. Environmental Protection Agency

Abstract

In waters classified for body contact recreation (swimming), the EPA recommends that the State include in its water quality standards the criterion that: "based on a minimum of five samples taken over a 30 day period, the fecal coliform bacterial level should not exceed a log mean of 200/100 ml nor should more than 10 percent of the total samples taken during any 30 day period exceed 400/100 ml." Water quality standards of virtually all States and Ter- ritories contain a fecal coliform criteria that is compatible with this recommendation. This criteria is the0basis for chlorination of sewage effluents discharged into water classified for body contact recreation.

On the other hand, EPA recognizes that chlorine and its reaction products are toxic to aquatic life and human health and recommends a water quality criteria in a water quality standard in the range of 2.0 - 10 ug/1 (as total residual chlorine).

According to a GAO report, about 74% of U.S. sewage plants use chlorine as a disinfectanti To prevent damage to aquatic life a few of these plants use dechlorination practices. The EPA encourages such practices and also recommends that States establish seasonal water quality standards under which chlorination would terminate during the months when body contact recreation and/or shellfish harvesting would not occur. Chlorine minimization requirements have also been developed for power plants where chlorine is used as a biocide. Simply put, EPA is on the horns of dilemma. It requires chlorination for human health reasons, but to protect aquatic life recommends limiting chlorine in water supporting fish. Recognizing this conflict, EPA will continue to:

1. advocate realistic classification of water contact recreation waters,

2. promote the use of seasonal WQS,

3. require chlorine minimization.

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4. suggest dechlorination, and

5. publish more definite criteria documents on the toxicity of chlorine to aquatic life.

I

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DISCUSSION OF EFFECTS

Dr. John Gottschalk: The record you have on the effect of chlorine on various organisms spoke of fish. Can you give me some idea of what the ages were? Except for the two points where there was larvae, the rest of the fish were subadults, juveniles or what age groups would you say?

Dr. Roberts: The figure includes a data for a mix of adults and juveniles depending on the species that are included. We are looking at an array of about six different species of fishes.

Dr. Gottschalk: So that the comparison functionally would have been between adult or subadult fish and juveniles of the oysters or crabs?

Dr. Roberts: There are data for larval fishes in the figure, including those two outlying points as well as points in the bulk of data.

Q: Did you say that 0.01 and 0.02 were just about the detectable limit and just about the safe limit?

Dr. Roberts: I said that that was just about the concentration, the minimum concentration, at which you see acutely lethal effects and that is coincidentally approximately the level that most people can measure routinely in the laboratory or the field. ..

Q: Oystermen say that, in the Potomac, they used to get certain bad years, then good years. But, in the lower Potomac they have not had any good years for a long time, even though now the River is much cleaner after Blue Plains has improved its operation. Has anyone been doing any research on that is my question? You had a rather limited amount of data on oysters.

Dr. Roberts: Not that I'm aware of.

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Dr. Cabelli: I would like to ask the last speaker on what unequivocal scientific basis he establishes that it was the chlorine that created the problem?

Mr. Wester: This was very easy after looking at the devastation that chlorine was causing to the cattail plants at Goose Island just below the discharges of this pollution. This is what they would call smoking gun evidence.

0: Just a little bit of clarification. The Possum Point Power Station only chlorinates cooling tower blowdown for Unit 5, the other four units do not chlorinate.

Lee Clayman: In terms of the degree of toxicity that has been reviewed both in laboratory and in field studies, has there been any correlation at all with long term and protracted low flow periods in the tributaries such as the Upper Potomac., and the Patuxent, and those emptying into the Bay area itself? Is there any correlation at all between protracted low flows and any increase in the incidence of toxicity?

Mr. Wester: As a result of Agnes, it was not low flow. It was just excess flood water that flushed an awful lot of chlorine down the Potomac. And, it was under these conditions that all the potamogeton growth in the Poke Creek Marsh were destroyed. The following year I saw clear evidence of this from the fact that the water outside this marsh was discolored brown from the color that was generated from the decomposition of. this vegetation. This vegetation has not come back at all. And, the reason it has not come back is that predation has prevented its recovery. So predation is a terrific factor with chlorine pollution in destroying the ecology of this estuary.

Q: What predator?

Mr. Wester: I think practically the whole fish world is the predator here. The fish feed on all kinds of microscopic invertebrate life that live with the submerged aquatic plants. In order to get at these food chains, they no doubt damage the plants that these food chains colonize. If the aquatic plants are in short supply, you are going to have the food chains in short supply. This puts pressure on the predators to go after their food and desperately, to prevent starvation, and as a result they destroy the valuable aquatic plants. So, what happens is the ecology just self destructs itself.

Q: What about turbidity as a factor?

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Mr. Wester: That is a minor factor. I know turbidity has been blamed for depressed growth of submerged aquatic plants, and I know it certainly is a fact, but it is just a temporary condition. And as soon as the turbidity conditions improve then the plant life improves.

Lee Clayman: Gentlemen, I think my question probably is more directed to Dr. Roberts than any of the others. I am referring to the amount of volume of chlorine that is used in the sewage treatment plants and specifically during those periods of protracted low flows in the river. Has there been any evidence to suggest that there is any correlation between the amount of toxicity and the effects of chlorine and the low flow itself?

Dr. Roberts: 1 know of no data that would allow us to make any careful analysis of that. There would be less dilution during periods of low flow, but this would also be true for other compounds that are being introduced. It really becomes a question that George Helz would have to get involved in in terms of what chlorine species are going to be there before we can say too much about it toxicologically.

Dr. Cabelli: You have really intrigued me with the statement with regard to that Virginia fish kill. Now let me set up a scenario. You decrease the chlorine concentration, somebody at a beach or some shellfish comes up with five cases of hepatitis. I am the lawyer for those people. I am suing the State and I am saying: What right did you have to reduce the chlorine concentration at the plant without consideration to the potential health effects?

Dr. Roberts: The decision was made by a collection of Virginia agencies. The Virginia Institute of Marine Science was least of all involved, because we do not have regulatory authority. The decision involved the State Health Depart- ment and the Bureau of Shellfish Sanitation, the State Water Control Board and the sewage treatment plant of the sanitation district involved. It was not a reduction to totally eliminate chlorination but a reduction in chlorination to meet the then existing state requirement for chlorination. The plant had been, in fact, chlorinating excessively. Kepone is an enigma that keeps coming back to haunt us, and I guess will for a long period of time. Unfortunately, Vince, as far as I'm concerned, we don't have the data to make a careful evaluation of the relative impact of kepone vs. chlorine in that situation. We have data from the field showing that if you took water during the time that the fish kill was occurring, put it into a tank, and you put fish taken from elsewhere (fish

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that had not been exposed to kepone) into that water, they died. If you took that same tank and added sodium thiosulphate to it, thereby eliminating the total residual chlorine, and put fish into it, the fish survived. That is circumstantial evidence that chlorine was the problem. It may not have been the only problem. There are other things that react with reducing agents such as thiosulfate. The only reason I brought up the field work is that it provided the impetus for the laboratory work into acute toxicity.

Dr. Olivieri: So the final point is that we are not sure what caused the fish kill.

Dr. Roberts: In that particular case, no. We cannot be absolutely, unequivocally sure of what caused the fish kill, because we cannot yet connect field data with laboratory data in any precise and rigorous way.

Q: Could you clarify the effects on crabs with regard to magnesium?

Dr. Roberts: In that study, we measured serum levels of the magnesium ion after crabs had been exposed to chlorine for four days. At levels of total residual chlorine higher than about 0.5 parts per million residual, we found that magnesium levels in the crab went up. This chart shows that magnesium regulation seemed to be disrupted and the crabs in that particular salinity were hyporegulating their blood magnesium levels. That meant their blood magnesium levels' were regulated to levels lower than those in the sea water or in the estuarine water that I was using. All I was saying was that that regulation was disrupted. What I actually saw in the crabs was that their serum magnesium levels were rising.

Q: What effect would that have on the crabs?

Dr. Roberts: It's hard to say because when we observed the "sublethal" effects, the crabs were dying anyway. In fact, they were at levels so close to the lethal levels of the crab, we could not really be sure if that particular effect was causing the crab to die or if the crab was losing its regulatory ability because it was dying. Now, magnesium has been injected into crabs and the higher levels of magnesium have been shown to depress neural activity. May- be that's it. Maybe it upsets magnesium regulation. We could not really tell from that study.

Dr. Heyward Hamilton: I wanted to return to the question of whether the loss of aquatic plants in the Potomac was due to chlorine or not. I am not convinced by the evidence that

Page 47

has been presented. I think one point that one needs to keep in mind with chlorinated effluents is that the chlorine itself decays quite rapidly and it is quite difficult to trace any distance from the source. You can perhaps trace it a kilometer or two, but not the tens of kilometers to where the effect of loss of wild rice was shown in the slides, for example. Now there may in fact be non-oxidative byproducts of chlorination that do get transported that far, although, we do not as yet know what they are, if they exist. But the chlorine oxidants, those things that are determined when one does a chlorine analysis, simply don't get transported far enough to be blamable for a regional effect.

The other comment I would like to make is that in an area where you have a lot of sewage treatment plants and a large urban center, there are many things that may correlate. When chlorine practice comes in, many other things are also coming in. Nineteen fifty is not too bad a base date to measure the use of lead in gasoline. But, there are many other pollutants thSt were increasing dramatically in concentration in that period. So I find the evidence uncon- vincing .

Mr. Cal Sawyer: I would like to respond to the statement that the Virginia State Health Department and its Bureau of Shellfish Sanitation agreed that chlorine was, or as it was sort of indicated, agreed that chlorine was the principal agent causing the 1973-1974 fish kill. That's simply not true. The Health Department did not, and does not, agree that chlorine was a major cause of that fish kill. And, on a total pound basis, the Hampton Roads Sanitation District plants in Williamsburg, James River, and Boat Harbor are now using about twice as much chlorine monthly as they were in 1973 and 1974. Therefore, with these low flows, we should be seeing a major fish kill here pretty soon.

Dr. Roberts: I did not say that the Health Department agreed with the conclusion that chlorination caused the fish kill. All I said about the Health Department and its Shellfish Sanitation group is that they were involved in the Chlorine Task Force and they were involved in the decision on the basis of which the chlorination dosage was reduced in the plant, at the time of the fish kill, and I believe that's a true statement. I do not know that you can draw a relationship in your final point between the amount of chlorine that is added to a sewage treatment plant, as a dose, and the amount of chlorine residual that will occur in the effluent. From the last data that I saw, we were observing only 0.02 milligrams

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per liter chlorine residual in the receiving water at the discharge point. That is approximately at the lowest lethal level that has been observed for any estuarine organism. As you move half a mile or less away from that plant, you do not observe acutely toxic residuals. I am not saying that there are not sublethal effects elsewhere.

Mr. Sawyer: Any later measurements taken after you made those initial measurements with your analyzer have never shown those levels that you claim or your field people claim that they have measured, and we do not see any evidence that those measurements were the least bit accurate, or have ever been verified.

Dr. Roberts: At the time that those measurements were made, I am sure that they were very crudely made. Everything, as you are well aware, was put together in a very, very short span of time. The various agencies were all utilizing different methods of analysis and so there has been some discussion and debate about the exact figures.

Dr. Cronin: I participated in the development of the green book and that was the first time we were able to clearly separate out the marine and coastal environment from fresh water in establishing criteria. We worked very hard in trying to make the case for that, pointing out the differences and the reason for differences in criteria. Did I understand you correctly in saying that that is now being reversed, that the inclination is to go toward a unified number for fresh water?

Dr. Rubin: Not exactly true. Right now the lead expert, let's say the person who's responsible for at least giving us guides in chlorine, a person named Dr. Bill Brungs at Narragansett believes that for most species, I believe both marine and fresh water, a single number of three micrograms per liter is probably appropriate. When we publish the new criteria for chlorine in December for public comment, I think you will see one number for fresh water and one number for marine.

Dr. Cronin: I would like to support the concept that we found true then, that I expect is still true, that no one individual has all the points of view that have to be taken into account in establishing criteria. It really is a complex task even though the answer may look simple when you get to it. The other point which we emphasized at that time, is that decisions must always relate to the site, to the situation and to the uses.

Dr. Rubin: Absolutely.

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Dr. Cronin: This is a sign of flexibility and intelligent response. It also frightens me a bit, because it opens doors for special cases. It opens doors for exemptions and for present conditions which preclude the future choices. It is a very difficult thing to apply, but so is an artificial national number which doesn't make sense in some situations.

Dr. Rubin: I think you have stated that very well. You're caught between a very restrictive single number and wide freedom of choice. There is substantial possibility for abuse, if it's not looked at and monitored very carefully.

Q: In your so called two number system, if you're allowed one sample, are you allowed to go over the limit per day?

Dr. Rubin; No. You could, theoretically, hit that number several times during a day, just as long as the overall average was not exceeded.

Q: Per day.

Dr. Rubin: Per day. Per twenty four hour average period.

Q: A single sample, or fifty samples, or...?

Dr. Rubin: That has not been defined and probably will be defined as we speak and work with the people in the office of enforcement, who have to do that when wasteload allocation procedures are developed for the criteria. We're working on that now. That's the link between standards and the actual permits themselves.

Mr. Henry Silberman: Dr. Rubin you referred to 3 micrograms per liter as the criterion, the lower value, which as you also pointed out is 0.003 parts per million. Correct?

Dr. Rubin: Correct.

Mr. Silberman: Now, any criterion, in order to observe it, has to be related to a limit of detectability. Would you please tell me what you think the average treatment plant can detect in terms of residual chlorine.

Dr. Rubin: Definitely abov^that.

Mr. Silberman: What is the limit of detectability as far as your branch is concerned?

Dr. Rubin: I think you have people a little bit better qualified to answer that who actually have done it. Is it 10 micrograms per liter?

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Mr. Silberman: In a laboratory of a university or a laboratory of a treatment plant?

Dr. Rubin: Well, in practicality we are talking about the level of let's say an EPA laboratory of any commerical laboratory, whoever is contracted to do compliance monitoring in that laboratory, whatever that is.

Mr. Silberman: My point is, we are setting a limit which we can't detect. If we detect down to .05 which may be very good we do not really know whether there is still something below that. How do we enforce the criterion as a standard at a level below the limits of detection?

Dr. Rubin: I mentioned the difference between a criterion and a standard. A criterion is our best scientific judgement of what level we need to get down to to insure that particular use of the water body. Let's say the use is to protect a marine fishery. It could very well be that we would have to consider the level of detectability before the final regulatory number is out.

Mr. Silberman: Thank you.

Sec. Coulter: I believe the GAO report that you referred to has a statement from the Communicable Disease Center (CDC) to the effect that the chlorination of sewage has little or no public health benefit. Did EPA refute the CDC on that statement?

Dr. Rubin; I do not know the details. We do not in all cases subscribe to that. We believe that chlorination is necessary to protect public health under certain situations. I cannot tell you what the level of response was back to GAO. I just got the report and looked at the report. Many people who were involved where this report was directed four years ago are no longer at the Environmental Pro- tection Agency.

Sec. Coulter: Would it be possible for us to find out if there was an official change on that point?

Dr. Rubin: Certainly, you are invited to speak to people in the criterion standards division. I could try to find out what the record is in that area and let you know.

Q: Is there a way to convert that so that we don't have to look up what a millimeter is or what a meter is and a few other things.

A: Parts per million equals milligrams per liter. Parts per billion equals micrograms per liter. The criteria document

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will appear in parts per billion and it will be two or five parts per billion that would translate to .002 to .005 per million.

Sec. Coulter: Dr. Cabelli, in your work you seem to have found a connection between polluted water and incidences of disease that a lot of people looked for and were unable to find. One of the things that I think I saw in there was the insight that you have to stratify your data so that you, as I understand it, actually distinguish between those people who had their head in the water, as opposed to those people that just came in casual contact. Was that a very strong classification, a very strong differentiation ! in your findings?

Dr. Cabelli: When a person was interviewed at the beach, we » asked the questions, 'Did you put your head in the water?' 'How long were you in the water?1 The first year we did the study we verified the responses. We sent teams of interviewers out to observe family groups and to see who had their head in the water. These individuals were asked subsequent to their day's swimming experience--'Did you have your head in the water?' The correlation was good. The correlation was not good on how long were you in the water and not at all on how long you had your head in the water. So we then categorized the respondents, head in the water vs. no head in the water. Consequently we had two populations to study. One, a group of people who had their heads in the water at sometime during the swimming experience and another population who did not. The control population, those individuals who did not, were at the beach and generally coming from the same family groups as the test population, the individuals who had their head in the water. We felt this was the best control we could have. I would point out to you that in the two previous studies that had been done, one in England, a retrospective study, and 'the one that was done in the United States back in the 1950's by the UHPHS, swimming was not defined that rigorously. This gave us the control population that we wanted. Also, we conducted our studies on weekends. Anybody who swam in the midweek, before and after the weekend in question, was thrown out of the j study, so we were able to isolate the effect with an > identified pollution level over one or two days at the most. Now I think these are the two things that allowed us to get the kind of information that was not obtained previously. That, plus the fact that we kept our minds open as to what the important symptoms would be.

I showed you data on swimming-associated gastroenteritis. We actually asked questions about a variety of symptoms and only symptoms that xêre consistently both

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swimming associated and pollution related were gastrointestinal symptoms. Then we asked the question, 'What indicator agrees best with the fluctuations in the rate of gastrointestinal symptoms from one weekend to the next in the course of several different studies?' That is what I showed you=on the slide concerning the work at New York City. And the answer came up enterococci. Then we continued the work with studies conducted at two other locations, Lake Pontchartrain and Boston Harbor, not to mention the study we conducted in Egypt. The American data brought us the kind of relationship that you saw, where we could' produce what we consider a criterion which is amenable to risk analysis and allows decision making, not a number, a relationship.

Sec. Coulter: As I understand it, the control was actually those people at the beach, not necessarily the ones who would get their heads exposed to the water.

Dr. Cabelli: The control was the people who were at the beach but did not put their heads in the water. We did not use in the study any individuals who were not at the beach.

o Sec. Coulter: Do you have any information about the general

population that is not at the beach compared to those that were?

Dr. Cabelli: We have assumed, and it is not necessarily so, that maybe the data on the control population might be used as an index of the incidence of illnesses in the population at large, but that is stretching it. I would suggest it is probably the best information you are going to find on the general rates of gastrointestinal illness in the population. We have assumed that. If you look at the ratio of swimmers to non-swimmers, the rate for swimmers was approximately twice that for non-swimmers.

Q: What kind of numbers were you getting in the chlorine at that time?

Dr. Cabelli: We did not make chlorine measurements in the bathing water per se. The source of pollution in the New York City study, the Lake Pontchartrain study and the Boston Harbor Study were all far enough away. The New York' City study dealt with material that was coming out of the Hudson, at least several miles away from the beaches at Coney Island, so that the probability that there would be any residual chlorine is very slim. They did chlorinate at some of the sources on a seasonal basis.

Merilyn Reeves: I have a question relating to risk analysis, because you have referred to the fact that it is not the

^

Page 53

basis of a number, but it is to establish a criteria. In the technology based standard setting that we do, we have to get down to a number, and I am at a loss to determine how a non-numerical range that you have indicated, in regard to criteria can provide us with the information that becomes necessary for law-enforcement purposes and for the regulatory process of setting standards.

Dr. Cabelli: I said this is a criteria. Now, the unknown factor is how much illness one is willing to accept. That is to say, what the acceptable risk is.--What risk is acceptable is a political decision properly made by politicians. They are paid to make these decisions. They are responsible to their constituencies. The input to these decisions are economic, sociological, and in fact, political. The only input that can be provided by biological sciences is the criterion itself.

Q: Studies have been done that show an adverse affect of chlorine on aquatic biology. Have any opposite studies been done showing the adverse affect of not disinfecting on aquatic biology? We've talked about humans. Have we studied the sea life itself?

A: There is some indication that sewage effluent has some toxicity associated with it, but it is not expressed in the same kind of terms that we use for the chlorination toxicity measure.

Q: Dr. Cabelli, I'm one of the people that sends the orders out when they close bathing beaches. When I asked the state laboratory if they can culture Enterococcus, they tell me they cannot. Is it practical to use Enterococcus as a standard?

Dr. Cabelli: Yes. If you go to the Journal of Applied Environ- mental Biology, you will see the method that we have developed for.counting Enterococci. You get the information back in about 36-48 hours, and they are easily enumerated by a relatively simple method. The performance characteristics of the method are in the article.

Q: So you are recommending that we convert to this?

Dr. Cabelli: We have for some considerable period of time. The comment was made that chlorination does not necessarily kill all indicators and pathogens, and I have two slides which show the chlorine effect on enteroviruses and the reduction of indicator densities by chlorine. There are some pathogenic organisms, that appear to be very resistant to chlorine. The agent that we are talking about here with gastritis, might, I repeat, might be one them. Never-

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theless, there can be no doubt that chlorine is effective in destroying most of the bacterial pathogens and some of the viral pathogens that are found in sewage. I think that is an irrefutable fact. There is a volume of experimental and field data to substantiate this.

Dr. Myron Miller: Your slide had your correlation curves logrithmic in Enterococcus density. Is there any model to explain why that should be so?

Dr. Cabelli: This is a dose response curve and the dose is basically bacteria and bacterial data tend to behave logrithmetically. This may be because the death of bacteria is exponential and the growth of bacteria is exponential. Most bacterial densities tend to normalize when they are essentially log-transformed. Now, you might have asked a related question. Why didn't that data look like a dose response curve?--that is to say a sigmoid curve, even when log-transformed. When you do a normal dose/response relationship, you will find that even with - log-transformation, you will get a sigmoid curve and that can only be straight- ened out if you do a log-probability plot. This is not a dose/response curve and the indicator is supposedly related to the number of pathogenic micro-organism which is related to the incidence of illness. Now if there is a differential die-off between the indicator and the pathogen, you can see that you would not get a sigmoid type response.

Del. Winegrad: Where are the pathogens measured?

Dr. Cabelli: These are not pathogens, these are indicators. In the sewage treatment, this is a post-secondary effluent coming out of the pipe. This is at the point of discharge. I calculated what the densities would be, with an initial dilution of 1-50, which is a good dilution. That gives the number you will end up with after the 1-50 dilution. Your target is the standard. What you need is at the minimum another 10-fold reduction. If you are dealing with a long distance outpour, you've got it made. You'll get that much from sedimentation, dilution and die-off. If you are putting your outfall, your source, close to--your target, a beach, a shellfish bed, you don't, have it. Then you have to depend upon something else. What? And as I said in the talk either you are going to disinfect or you are going to abandon that resource. There just is not much in the way of other choices. This is all very dependent upon the relationship of the source to the target--that is a case by case situation. That can only be considered in that context. There are no general rules for this. You have to take them one at at time.

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Q: In other words, with sufficient dilution there is no problem

Dr. Cabelli: They have five mile outball for Hyperian along the Pacific Coast. They don't chlorinate and I really don't think they have to go to secondary treatment in terms of protecting the beaches.

Summary:

Nancy Kelly: This has been a very interesting discussion on acute toxic effects of chlorine on a number of aquatic organisms. From this discussion, I think we have learned several things. One is that bivalves are more sensitive than other organisms to chlorine and that fish larvae seem to be more sensitive then the adults. Also, short term high concentrations of chlorine seem to be less damaging than longer term lower concentrations.

We also heard that concentrations of .02 parts per million or less seem to have, in most cases, no acute lethal impacts, and that, in general, power plant residual levels in the environment do not tend to exceed that level, at least beyond a certain distance in the environment. It is not clear that the same can be said in all cases of waste water treatment plants.

There was also a brief discussion of dechlorination and it seems that it is technologically possible to remove chlorine in order to reduce toxic levels from the effluent although care must be exercised to make sure that there is a careful balance between the levels of chlorine and the levels of sodium thiosulfate or whatever other agent is added. Dr. Laird gave us a very comprehensive summary of sub-lethal affects on a variety of species. I will briefly say that the sub-lethal affects include impacts on larval development, growth, reproduction, behavior any physiology. He gave some interesting examples of levels which are at or below the lethal doses but which in fish deformed larvae, reduced the growth, deformed the juveniles, or reduced egg viability. In molluscs, reduced growth rates and reduced reproductive capacity and many other impacts have been seen. Physiological impacts, may be serious, although they are hard to understand in terms of how they ultimately affect the behavior of that individual or population.

Mr. Wester gave us a discussion of reduced of abundance of submerged aquatic vegetation, changes in distribution of submerged aquatic vegetation in the upper Potomac estuary and his concern over the potential relationship between

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those and the use of chlorine. There were a number of questions asked about the relationship.

EPA is changing its approach to standards and will be coining up with new standards in the fall, proposing them for public comments. You may want to become involved in that process. They seem to favor an approach that would provide more flexibility on a case by case basis and allow the states to work with EPA to help set those standards on the case by case basis.

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A CHALLENGE TO CHLORINATION*

P.H. Gamett Department of the Environment

INTRODUCTION

An impartial observer might find it difficult to understand why two countries, that have closely related objectives in controlling water pollution and preventing associated health risks, should appear to have completely opposing philosophies in relation to the disinfection of sewage effluent. In the United States practically all discharges of sewage effluent to the aquatic environment are disinfected, and in the United Kingdom, practically none. The disinfecting agent used in the US appears principally to be chlorine.

The purpose of this paper is to put forward the UK point of view on disinfection of sewage effluents, and then to discuss, not necessarily to decide who is right or wrong, but rather how the two extreme viewpoints might have come about. The emphasis throughout will be on chlorination but reference will be made to alternative disinfectants.

It should be noted that in UK terminology, the expression 'sewage effluent' implies that sewage has been given some, form of treatment, consisting of at least primary settlement. When 'crude sewage' is used, it implies that nothing other than preliminary treatment, such as screening or maceration, has been given.

PUBLIC HEALTH CONSIDERATIONS

It might be thought that sewage effluents should be disinfected in order to inactivate pathogens, if they are discharged to water which could be used either as a source of water for agricultural purposes, or as1 public supply, or for recreation. (Water for industrial use can be excluded because the abstractor is responsible for the quality used and will provide any necessary treatment plant.) These three circumstances will now be considered.

(a) Water abstracted for agricultural purposes

In the UK water abstracted for this purpose has to be licensed and the Agricultural Development Advisory Service (ADAS),

* Britannic © Crown Copyrighti 1981

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which is an organization responsible to the Ministry of Agriculture, Fisheries and Food, will give advice on its suitability for a specific use. This advice is about to be reinforced by Codes of Practice that will refer to crop irrigation and also stock waterings. The Ministry also maintain a veterinary service whose advice is that in lowland areas, a 'secure' water supply should be used for stock waterings; with dairy farming it is a requirement. Nothing within this procedure would be changed even if all sewage effluents discharged to a river which is used for agricultural purposes were to be chlorinated. The chlorination of sewage effluents does not necessarily make a river water safe for agricultural purposes.

(b) Water abstracted for public supply

Public supply water is made safe for consumption at water treatment works. This and the possible harm to public supply that could result from the chlorination of sewage effluent is discussed later.

RECREATION

In the UK the maximum risk to health would appear to be during bathing when actual bodily contact with water containing sewage, including involuntary consumption, can take place. As very little bathing takes place in inland waters in the UK, it is essentially coastal bathing waters, known to contain sewage, which is of concern.

Whether or not the presence of sewage in bathing water constitutes a hazard to human health has been under consideration in the United Kingdom for many years. It does not seem, at first sight, unreasonable for the layman to assume that bathing in sea water contaminated by sewage might have harmful effects. Sewage does contain large numbers of bacteria, some of which may be pathogens.

The Public Health Laboratory Service set up a Research Committee in 1953 to study the possible hazard to health of bathing in sewage contaminated water and in their report the Committee concluded that the risk to health could, for practical purposes, be ignored.(1) In the report of the Working Party on Sewage Disposal (2) the subject was discussed at some length and the conclusion reached was that an apparent conflict between the bacteriological and epidemiological evidence had to be accepted and the risk to health from bathing in sewage contaminated water was minimal.

The potential microbial health hazards and their relation

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to sewage treatment in coastal waters have more recently been reviewed (3) and the same conclusion has been reached. There is still no evidence available in the UK to demonstrate that public health is at risk from bathing in sewage contaminated sea water. In the United States, however, studies have been made to establish if public health is at risk (18) and the same author's findings on his survey of US bathing waters have been critically appraised in the UK. (19) Nothing has so far changed the UK view but it is just possible that a survey may be carried out in the UK if a meaningful protocol could be devised.

The Consumers Association, a well known UK 'watchdog' organization, published each month the widely circulated and well read journal 'Which', advising the public on a wide variety of subjects. 'Which' carried out an independent survey of UK bathing waters (21) to assess health risks and concluded that even though there were signs of sewage on a number of beaches, bathing in sewage contaminated sea water did not appear to be a public health risk.

It should of course be understood that these comments on the risk to public health apply only to UK coastal waters and it does not follow that the same conclusion would be reached following an examination of other countries' waters.

Before leaving 'recreation' a reference must be made to the European Community Bathing Water Directive. (4) Within the Community a Directive has legal status and Member States have to comply with its requirements. Although the Bathing Water Directive covers both chemical and bacterial requirements, it is the bacterial ones that are of concern here. These require that the total coliform count should not exceed 10,000/100 ml, with the corresponding fecal coliform count not to exceed 2000.

Bathing waters are defined in the Directive as areas of either fresh or sea water where bathing is traditionally practiced by a large number of bathers. It is clear from this definition that the Directive will not apply to all UK bathing waters even though bathing actually takes place and indeed, 27 beaches only have been identified as coming within its scope.

The requirements of the Directive have to be met by 1985. Of the 27 identified waters it appeared that 2 would have difficulty with compliance unless major discharges of sewage were disinfected as a temporary expedient; others either complied now or would be expected to do so because of the proposal to provide suitably designed long sea outfalls.

This particular need to disinfect a sewage effluent derives from a legal requirement imposed on the UK and in no way changes

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the basis of UK opinion which is that no risk to public health, from bathing in water contaminated with sewage, has been demonstrated.

It would be difficult indeed, in the UK, to make out a case on public health grounds that would require sewage effluents to be chlorinated. Supposing, however, that sewage effluents were to be chlorinated, what effect would this be likely to have? Before attempting to answer, it might be helpful to note the treatment given to sewage in the UK.

SEWAGE TREATMENT IN THE UNITED KINGDOM

Over 99% of the volume of sewage discharged to inland (non tidal) rivers receives both primary and secondary treatment and in some cases, tertiary treatment (for example sand filtration or microstraining). The extent of the treatment provided depends on the use to be made of receiving waters and tertiary treatment is reserved for the occasions when a very high standard is required. The effectiveness of treatment is usually expressed as a reduction in the Biochemical Oxygen Demand (BOD) which in some instances is to below 10 mg/litre; effectiveness can of course be expressed in other ways.

It may be of interest to note that these treatment processes may be expected to reduce the number of bacteria present in the sewage up to about 100 times; the coliform count is likely to be reduced from about lO^/lOO ml to 10^/100 ml. The extent to which water borne viruses are removed by conventional treatment is more difficult to assess but recent work, as yet unpublished (5), indicates that about 50% is removed by primary treatment and secondary treatment also removes significant numbers, particularly in the activated sludge process. At one of the largest activated sludge plants in the UK, an overall 997o removal was achieved over a 6 months test period.

With discharges to coastal waters it is usual to provide either preliminary or primary treatment only, and then discharge through a sea outfall. It is accepted in the UK that a properly designed sea outfall provides a satisfactory means of sewage disposal.

EFFECTS OF DISCHARGES OF UNCHLORINATED SEWAGE EFFLUENT TO INLAND WATERS

The effect of discharging unchlorinated, and chlorinated discharges of sewage effluent to inland waters will not be considered.

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After a discharge of sewage effluent has been made to an inland (fresh water) river, a self purification process will commence and progress will depend on the capacity of the river in terms of its capability to absorb the discharge. In all ecosystems, food is made available through a succession of organisms, and within the concept of 'self purification', three groups can be identified:(6) producers (usually algae), consumers (animals) and decomposers (micro-organisms). Organic material enters the food chain either through scavengers or through decomposition by micro-organisms. An excessive discharge of organic material could result in an excess of nutritional material becoming available which could give rise to oxygen deficiency. In this discussion it is assumed there is not a nutrient inbalance and that downstream of a discharge of sewage there will be a progressive reduction of organic matter.

EFFECTS OF DISCHARGES OF CHLORINATED SEWAGE EFFLUENTS TO INLAND WATERS

A self purification regime will still be implemented but certain disadvantages may result from discharging chlorinated sewage. There are two circumstances to consider, firstly when a chlorine free effluent is discharged (pe.rhaps after dechlorination) and secondly when the effluent contains residual chlorine.

(a) Chlorine absent

A first disadvantage is that any chemical compounds present in sewage will be subjected to chlorination and there is abundant evidence that some chlorination does take place.(7) The chlorinated substances could be more toxic and less bio- degradable than the substances originally present in the sewage, for example, in the case of chlorophenols. Unless there is an immediate dilution, sufficient to counteract the increased toxic effect, a receiving water could suffer.

A second disadvantage is that bacteria which could have a useful role to play in self purification in the river could be destroyed. During secondary, or tertiary, treatment strains of bacteria may develop that have specific capabilities to bio- degrade organic compounds and without chlorination these bacteria will be present in the sewage effluent discharged.

A third disadvantage, more speculative although there is some evidence in support (5), is that the chlorine dosage to disinfect sewage effluents is not likely to destroy water borne viruses in which case the viruses are likely to survive longer because of the reduction in the number of predatory

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protozoa and bacterial activity.

To these disadvantages must now be added those incurred if there is a residual chlorine content present in the sewage discharged.

(b) Excess chlorine present

This means that a highly toxic substance will be discharged and until such time as its effect is spent, it could cause a great deal of harm. The self purification process depends, as set down earlier, on a chain of events and depending on their relative resistance to chlorine, certain grazing organisms may be removed, disrupting the natural self purification sequence. In an extreme case, where sufficient chlorine is present to impart a taste to the water, fish flesh may become tainted and rendered unsuitable for human consumption.

On ecological considerations, chlorination of sewage effluents to inland waters appears to be a disadvantage; it could retard the self purification processes and introduce chlorinated compounds into the aquatic environment which are more toxic than the substances originally present in the sewage.

SEWAGE CHLORINE AND BACTERIAL GROWTH

It would not be appropriate in a paper of this kind to ignore the information available on bacterial regrowth. A review of sewage disinfection in Canada (8) concluded that regrowth would only occur in slow moving, nutrient rich rivers with a temperature in excess of 20 degrees C. Work recently carried out by the Water Research Centre in the UK (9) indicates that regrowth in saline waters can occur at lower temperatures and it is the dilution available for a chlorinated sewage discharge that very largely governs regrowth. It is quite possible, in the UK, that regrowth problems would arise because of the many slow flowing, nutrient rich lowland rivers that may contain 10% or more of sewage effluent under dry weather conditions.

Ten years or so ago the reasons given up to this point could well have summarized the UK case against the chlorination of sewage effluent. There is now, however, a more urgent reason and this is primarily concerned with public water supply.

WATER ABSTRACTED FROM LOWLAND RIVERS FOR TREATMENT AND PUBLIC SUPPLY

In the UK about one-third of the water put into public

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supply comes from lowland rivers. It is not unusual under dry weather conditions for more than 10% of the river flow to consist of sewage effluent that in turn is quite likely to contain appreciable quantities of industrial effluent.

Abstracted water is treated before being put into supply and this treatment will usually consist of coagulation and filtration to remove suspended solids; partial softening (if necessary); pH adjustment (if necessary) and finally disinfection, for which chlorination is normally used.

Over the last 10 years increasing interest has been taken in organic compounds present in trace quantities in water, following the knowledge that long-term exposure to low concentrations could be an important factor in disease. The possible significance of trace quantities of certain organic compounds in public water supply is reviewed elsewhere. (10)

As a consequence, a considerable amount of work has now been carried out in the UK to identify organic compounds present in. both river water and treated water, put into supply. The Water Research Centre, under contract to the Department of the Environment, has so far identified some 2000 compounds in river water, and about 360 compounds in treated water. (11) These compounds are present in extremely low concentration and how many of these compounds can significantly affect health is not yet known, but a considerable effort is being made to find out. (10) High on the list of suspects are the trihalomethanes as suspected carcinogens, and chlorouracil as a suspected mutagen. A review of the literature has recently been carried out in the UK by the Water Research Centre. (7)

An interesting point is that work in the UK (10) has shown that the trihalomethane content of untreated water can be quite low (less than 1 yg/1) compared with water after chlorination (values in excess of 80 yg/1 have been reported). There is evidence, as yet unpublished, which shows that the chlorination of surface water can produce mutagens which can persist through conventional water supply treatment processes. (20)

Because of the apparent production of trihalomethanes during chlorination, the practice of prechlorination, in order to prevent algal growths and slimes that can interfere with treatment plant machinery, is now being discouraged and chlorination should be reserved as the last stage before the water goes into pub Lie supply.

A further disadvantage that would result from the chlorination of sewage effluents will now be immediately apparent. Organic substances present in sewage discharged to a river may

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well suffer biodegradation, if unchlorinated, before reaching a public supply abstraction point (in the UK such abstraction points are invariably placed well downstream of sewage effluent discharges). The chlorinated compound might well be much more resistant to biodegradation with the risk that it could be present in abstracted water and pass through a treatment works and into public supply.

THE EUROPEAN COMMUNITY BATHING WATER DIRECTIVE

Reference has already been made to the Bathing Water Directive and its associated bacterial standards which were not likely to be met in 2 out of the 27 UK bathing waters identified as coming within its scope.

Even though there is no evidence available to suggest that there is any risk to public health from bathing in sea water contaminated with sewage effluent, it is a legal requirement that the standards of 10,000/100 ml total coliform, and 2000/100 ml fecal coliform counts be met.

With one of the bathing waters it is a direct discharge of comminuted sewage to an estuary that is responsible for the non-compliance, with the other it is a large treatment works discharging sewage effluent to the seaward end of an estuary which reaches the open sea in close proximity to a bathing water, that is responsible.

In the case of the discharge to an estuary, the possibility of disinfecting the sewage effluent was examined (12) and the conclusion reached was that chlorination would be effective and its use as a temporary measure should allow the standards prescribed under the Directive to be met.

Chlorination was applied at a rate of 15 mg/litre during the bathing season of May-September, commencing in 1977 and the results to date.show that the requirements of the Directive can generally be met.

The dilution available for the discharge of the chlorinated sewage is considerable but the receiving water has been kept under surveillance to see if there is any build up of organochlorine compounds.in marine life. Up to the present time no increases of any significance have been observed but surveillance will continue.

c

Although in this instance chlorination has been successful in allowing legal bacterial standards to be met it has to be emphasized that chlorination of sewage effluents discharged to coastal waters is to be recommended in the UK only as a

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temporary expedient and correctly designed sea outfalls are preferred. The chlorination of sewage effluents could give rise to the release of a wide range of organochlorine compounds into the marine environment and this would be unfortunate when the present indications are that such discharges should be discouraged .

In the case of the other bathing water, where the estuary discharges to the sea in close proximity to the bathing water, chlorination could be given to the discharge of sewage effluent to the estuary but very close control would need to be applied, and dechlorination added, in order to prevent either free chlorine or chloramines entering the estuary as this could interfere with the passage of migratory fish. Other disinfectants are being considered including ozone, which may be expensive and could give rise to undesirable breakdown products (that could in turn produce unwanted bacterial growths) and UV light which although expensive, does not produce unwanted substances. Peracetic acid is also being considered but this has the disadvantage of allowing acetic acid to enter the estuary. (13)

ALTERNATIVE DISINFECTANTS

The discovery that organohalogen compounds can be formed during chlorination has led to programmes of work in both the UK (14) and the US (15) in which the effectiveness and relative costs of using alternative disinfectants have been examined.

The work has been concerned with the disinfection of water put into public supply, rather than for treating sewage effluent and the conclusion reached in the UK is that either ozone (14 & 16) or chlorine dioxide (14' & 17) could be used without sacrificing hygenic quality but they would be more expensive. In the case of ozone however the capital costs in changing over would be very considerable because it would be difficult to fit an ozone treatment process into an existing works layout; no such difficulty would of course arise with a completely new works.

Before any change-over to either ozone or chlorine dioxide is to be contemplated, the current UK view is that an existing chlorination procedure should be examined in order to see if it can be made more effective. (It cannot of course be said with any certainty that such a change over would not give rise to its own problems because compounds that may be produced have not been investigated to the same extent as those formed during chlorination.) In particular the treatment provided before chlorination should be reviewed and perhaps modified, or more carefully controlled, in order to reduce particulate

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matter (including micro organisms) passing forward into the chlorination stage. If, however, the organohalogen problem, particularly with trihalomethanes, is of significance, then a change over to ozone or chlorine dioxide may be necessary. (14)

Reference has already been made to a possible alternative to chlorination for the disinfection of a sewage effluent, but the investigation is not complete.

DISCUSSION

The view held in the US is that all sewage effluents should be disinfected and chlorination is the usual means of achieving this. The view held in the UK is that there is no identified need to disinfect sewage effluents but if for some reason one arose, chlorination would be a procedure to consider.

On this basis the advantages and disadvantages of chlorination for disinfection can be examined and on the evidence put forward in this paper and in the prevailing UK circumstances, the case against chlorination is convincing and can be summarized as follows:

(a) the self purification procedure in a river could be retarded;

(b) the passage of migratory fish could be interferred with;

(c) substances of increased toxicity and less biode- gradability could be produced from substances present in sewage;

(d) the quality of water put into public supply could be impaired;

(e) fish and shellfish destined for human consumption could be tainted; and

(f) it could result in the release of additional organohalogen compounds into the total environment.

Compared with these reasons, what are the advantages? From the UK viewpoint essentially none, but from the US viewpoint there may be some.

The underlying debate is not, of course, should chlorination of sewage effluents be carried out but rather, is the disinfection of sewage effluents necessary? Such a debate is outside the terms of reference of this paper, and indeed, of

Paqe 67

the conference itself but a few observations may not be totally out of place.

The UK view is still 'No'. Disinfection appears not to be necessary, at least not on health grounds. In the two cases where disinfection is to be used it is in order to meet legal requirements.

It is here that differing philosophies may be apparent. It could be the US point of view that if a potentially noxious substance has been found to be present in water which could be used as a source for public supply, or with which the public could come into contact, then it is advisable to remove the substance. Putting this a different way, it could be said that an additional barrier to the spread of disease should always be provided where it is practicable to do so and disinfecting sewage effluents does just this.

The UK procedure is perhaps more inclined firstly to establish a need for action, secondly to consider the cost of taking action and thirdly to consider likely ensuing benefits.

But setting aside this possible different approach, the circumstances in the two countries are very different; UK lowland rivers are generally short in length, of low flow, ahd slow moving. In contrast US rivers are in general considerably longer and of greater flow, though not necessarily more fast flowing. The dilution afforded to discharges of sewage effluent could be much greater in the US and the conT centration of any organohalogens formed in chlorination processes are therefore likely to be low in receiving waters, the total quantity discharged may of course have a significance in terms of possible ultimate effects on the total environment. There may well not be problems due to bacterial regrowth in the US, as there would most likely be in the UK, because of the greater dilution. More, repeated, use of rivers for agricultural purposes may need to be.made in the US, where in isolated areas piped water may not always be available. In such a circumstance it may be considered necessary to impose bacterial standards on water abstracted and in order that such standards can be met, disinfection of sewage and some industrial effluent discharges, may be necessary.

FINAL COMMENT

Although some explanation for the different viewpoints held in the UK and US on the need to disinfect sewage effluents has been offered, it is still apparent that there are questions remaining to be answered. The author is not however seeking a confrontation but is looking forward more to an exchange of information which might enable the separate viewpoints to be understood, if not reconciled.

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References

1. Sewage contamination of bathing beaches in England and Wales. Medical Research Council Memorandum 37. London, HMSO, 1959.

2. 'Taken for granted'. Report of the working party on sewage disposal. London, HMSO, 1970.

3. BARROW, G.I. Microbial pollution of coasts and estuaries: the public health implications. Journal IWPC, 1981, 2, 22.1

4. Commission of the European Communities. Council Directive concerning"the quality of bathing water. Journal L31, Brussels, 1976.

5. SLADE, J.S. Thames Water Authority, London. Private communication (work not yet published).

6. HAWKES, H.A. 'Some effects of industrial effluents on the biology of r,ivers' . Journal IWPC, 1968, 3, 276.

7. IRVING, T.E. and SOLBE, J.F. de LG. Chlorination of sewage and effects on marine disposal of chlorinated sewage; a review of the literature. Water Research Centre Technical Report 130, Stevenage, 1980.

8. Wastewater disinfection in Canada. EPS 3-WP-78-4. Water Pollution Control Directorate, Environment Canada, Ontario, 1978.

9. IRVING, T.E. Sewage chlorination and bacterial regrowth. Water Research Centre Technical Report 132, Stevenage, 1980.

10. FIELDING, M. and PACKHAM, R.F. Organic compounds in drinking water and public health. Journal IWES, Sept. 1977, Vol. 31, No. 5, 353.

11. Water Research Centre. 'A comprehensive list of polluting- substances identified in fresh waters, effluents, aquatic - animals, plants and bottom sediments.' Second edition. Stevenage, 1976.

12. TOMS, R.G., SAUNDERS, C.L. and HODGES, E. The control of bacterial pollution caused by sea discharges of sewage. Journal IWPC, 1981, 2, 204.

13. TOMS, R.G. Wessex Water Authority. Private communication.

14. ' RIDGEWAY, J. and WARREN, I.C. Water Research Centre.

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Seminar on trihalomethanes in water. Stevenage, 1980.

15. CLARK, R.M. Evaluating costs and benefits of alternative disinfectants. Journal AWWA, 1981, 2, 89.

16. SANKEY, K.A. and WHATMOUGHT, P. Experiences in the use of ozone. Journal IWES, September, 1980, Vol. 34, No. 5, 435.

17. BRETT, R.W. and RIDGEWAY, J.W. Experiences with chlorine dioxide in South Water Authority and Water Research Centre. Journal IWES, March 1981, Vol. 35, No. 2, 135.

18. CABELLI, V.J. Evaluation of recreational water quality, the EPA approach. Symposium proceedings 'Biological Indicators of Water Quality'. University of Newcastle, 1978, Vol. 2.

19. CABELLI, V.J. "A health effects data base for the derivation of microbial guidelines for municipal sewage effluents." Coastal Discharges, Engineering Aspects and Experience. I.C.E., London, 1980, preprint 29-33 (discussion not yet published).

20. TYE, R.J. and WAITE, W.M. Severn Trent Water Authority. Private communication (work not yet published).

21. Consumers' Association Publication 'Which'. July 1973. 14 Buckingham Street, London WC2N 6DS.

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DISINFECTION OF SEWAGE EFFLUENT THE AMERICAN APPROACH

Vincent P. Olivieri

Environmental Health Sciences The Johns Hopkins University

School of Hygiene and Public Health

i

In the United States, terminal disinfection of sewage effluent before discharge into the environment has evolved as one of the multiple barriers against the transmission of infectious disease by the water route. Disinfection of treated sewage has been intended to reduce the levels of pathogenic microorganisms such that there was no detectable level of water borne disease. The primary concerns have been three:

1. The protection of sources of drinking water. 2. The protection of shellfish harvesting waters. 3. The provision for safe close-contact recreational

waters.

It should be noted that disinfection was never intended to sterilize (complete destruction of living material) the sewage effluent nor even reduce the numbers of microorganisms such that the effluent could be consumed without further treatment. Disinfection of sewage effluent was intended ' as a preventive practice to minimize the reintroduction of human pathogens into the environment. E.B. Phelps (1909) summarized the rationale for sewage disinfection:

".... in the fight against infectious diseases, sound tactics demand an attack on the enemy as near as possible to the initial source of infection. The best and easiest.place to destroy typhoid germs is at the bedside of the typhoid patient; but this method cannot be relied on to keep sewage free from infection and the next strategic point is certainly the sewage. Once at large the germs may reach their victims in a score of well-known ways,...."

While the massive waterborne outbreaks of typhoid and cholera have not occurred in the United States for quite some time, enteric diseases can still be found in the population and several thousand cases of waterborne diseases occur annually. These small waterborne epidemics generally occur when the multiple barriers are breeched and coupled with a multiplicity of blunders which result in transmission of disease. Conventional sewage treatment (thru secondary

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processes) does little to remove human pathogenic microorganisms. Table 1 shows the level of Salmonella sp after secondary treatment at the Back River sewage treatment plant in Baltimore, Before disinfection, the density of Salmonella was 6.6 x 10-V10 liters. No members of the genus Salmonella were recovered after application of chlorine.

Sample

Salmonella sp.

MPN/100 1

Total Coliform

MPN/100 ml

Fecal Fecal Coliform Streptococci

MPN/100 ml Number/lOOml

raw sewage 6 X 10' 2.2 X 10 6.3 X 10' 1.4 X 10'

trickling filter 6.6 X 10" 8.3 X 106 2.2 X 106 2.2 X 105

chlorinated effluent LSL 6.3 X 101 4.0 X 10° ND

LSL - Lower sensitivity limit of the assay. No microorganisms recovered. , ND - Not determined

TABLE 1. Geometric Mean Density of Salmonella sp. and Indicator Bacteria in Samples Collected at the Backriver Wastewater Treatment Plant in Baltimore, Maryland.

In the absence of disinfection, the pathogens may survive for considerable time in the water column and bottom sediments. Figure 1 shows the survival of natural populations Salmonella sp and indicator bacteria in sewage effluent at 24 degrees C. Salmonella sp were recovered after 14 days. Brezenski et al. (1965) reported the occurrence of natural populations of Salmonella in chlorinated and non-chlorinated sewage effluents and receiving waters. A total of 102 samples of chlorinated sewage effluents from plants located on the Raritan river and Raritan bay were analyzed. Salmonella sp were not recovered. When chlorination was discounted. Salmonella sp were isolated from the sewage effluents, but more important were recovered from samples collected downstream at the tidal portion of the Raritan river (salinity^10 parts per thousand). After chlorination was resumed, all samples collected over a 15 week period at the sewage treatment plants and the Raritan river site were negative for Salmonella.

Page 72

Figure 1. Survival of Natural Populations of Salmonella sp. and Indicators in Trickling Filter Effluents of 24 degrees C.

Kempelmacher et al. (1970) evaluated the removal of Salmonella from sewage treatment processes (trickling filter) in the Netherlands. They reported that only 90% removal could be expected from the conventional secondary sewage treatment plant. While 1010 Salmonella per hour enter the plant, 10^ Salmonella per hour were released into publicly accessible water. These European researchers concluded

the feasibility of disinfection of effluent merits consideration." '

The simple isolation of a pathogen does not mean disease but the presence of the organism is necessary as a pre- requisite for infection. The above data simply points out that disinfection of sewage effluents dramatically reduces the spread of human pathogens particularly enteric bacteria. Human enteric viruses appear to pass thru the sewage treatment processes in a manner similar to the Salmonella. Studies

Page 73

conducted by our laboratories showed that the terminal chlorination of sewage was responsible for the significant portion of viral removal (Naparstek et al. 1976, and Sherman ®t al. 19 76). Viruses are inactivated during the chlorination process. They are readily inactivated by free chlorine, which is only a transient chlorine species in sewage effluent chlorination as currently practiced; and more slowly inactivated by monochloramine, which is the major species of chlorine present during terminal sewage chlorination (Olivieri et al. 1970, Kruse' et al. 1971, Kruse' et al. 1973). Disinfection practice and process design become key factors for removal of virus with chlorine. While there is considerable room for improvement, current levels of inactivation of virus with chlorine appear to be adequate to control the transmission of virus diseases by water.

Outbreaks of disease in the United States associated with municipal supplies have resulted from contaminated raw water coupled with poor water treatment practices or inter- ruption of treatment processes. Sewage disinfection minimizes the level of human pathogens and promotes the microbial quality of the receiving water. Aftergrowth of micro- o^9^îsms in disinfecte.d effluents is a result of saprophytic microorganisms that are enumerated in the total coliform measurement. Few reports of aftergrowth of fecal coliform can be found and little data was available to indicate that enteric pathogens were observed in the aftergrowth. Human enteric viruses and protozoan cysts are obligate parasites and do not grow in the natural aquatic environment. Disruption of downstream biodegradation of remaining sewage nutrients by chlorinated sewage effluents is unlikely when sound disinfection practices are employed and a reasonable dilution of the effluent occurs in the receiving body of water. The levels of total residual chlorine observed below a sewage outfall drop very quickly and it cannot be detected after the mixing zone. Figure 2 shows the level of total residual chlorine in the Little Patuxent River below the sewage treatment plant at Fort Meade. Despite the fact that this treatment plant was an old trickling filter plant with an effluent of only mediocre quality, the level of total residual chlorine found in the stream was low and was observed only a short distance below the outfall. Chlorinated sewage effluent from a well operated treatment works will have minimal effect on the stream and minimize the microbial contamination of surface waters that may be sources for municipal water supplies.

The protection of shellfish - harvesting areas is an important function of sewage disinfection. The reductions of enteric pathogens, both bacteria and virus, coupled, with a no-harvest buffer zone below the plant and modern shellfish

Page 74

z o »- < (E I- Z UJ o z o o

h- 3 o

u. o

< a:

CO <

< 3 a (0 UJ a;

UJ z a: o _i

o

< f- o

0.01 -

0.001 0 0-2 0-4 0.6 UjB l0 |2

DOWNSTREAM DISTANCE FROM OUTFALL IN MILES

Figure 2. Total chlorine residual in the Little Patuxent River below Fort Meade Sewage Treatment Plant #2 for different dilution factors.

Page 75

sanitation programs have resulted in an enviable record. Shellfish outbreaks of enteric disease still occur in Italy and France where sewage was not disinfected. The report to Congress by the Comptroller General of the United States (1974), while critical of sewage disinfection with chlorine, recognized the value of terminal disinfection of sewage effluents for the protection of shellfish growing waters.

The detrimental effect of chlorine species on shellfish has been demonstrated in the laboratory but cannot be supported by field data. Levels of residual chlorine necessary to inhibit shellfish productivity are rarely if ever observed in the estuary. Residual chlorine cannot be distinguished from other oxidants present below 0.05 mg/litre. Other factors appear to be responsible for the cycles of shellfish productivity. Recent reports suggest that salinity was the prime factor in the setting of oysters in the Chesapeake bay (Walsh and Fincham 1981).

In the United States both fresh and saline waters are used extensively for contact recreation. In the United Kingdom, contact recreation on any scale is limited to the coastal areas. Only 2 7 beaches in the U.K. are large enough to fall under the European Community Bathing Water Directive. Early studies in the United Kingdom (Moore 1954 a, b) suggested that the risk to health by bathing in sewage contaminated waters was negligible. The diseases followed in these studies were poliomyelitis and salmonellosis. Poliomyelitis, after almost 50 years of epidemiological study, does', not appear to be waterborne (Mosely 1967 , Goldfield 1975) and thus would not be expected to be transmitted by contact recreation. Salmonellosis has been transmitted by water, but the number of Salmonella that must be ingested to cause disease is greater than 10^ fBryan 1974). The quantity of recreational water that would contain this number of Salmonella would not be expected to be consumed by bathers. Thus, it was not surprising that the early studies reported that enteric diseases were not associated with swimming.

<

Stevenson (1953) in the United States reported the results of a series of field studies to determine the relationship between health and bathing water quality. The studies demonstrated that swimmers had a higher over-all incidence of disease compared to non-swimmers, regardless of water quality. Swimmers under 10 years of age had almost 100% higher illness rate than those over 10 years of age. Cor- relation at the 99% level between illness and bathing water quality was shown at Lake Michigan at Chicago, Illinois. The evidence however was not considered conclusive since only a short period of time was used during the comparison between "poor" and "good" water quality. Significant

Page 76

increase in gastrointestinal disturbances were observed in swimmers in the Ohio River where the total coliform level was 2700/100 ml.

Studies conducted by Cabelli et al. (1975, 1976, 1977) suggest that enteric disease was transmitted by contact recreation and that the level of disease was related to the level of contamination as indicated by the density of enterococci. Additional discussion can be found in Cabelli's report in this volume.

Recent outbreaks demonstrated that other enteric diseases are transmitted by contact recreation. A shigellosis outbreak in 1974 in Dubuque, Iowa was related to swimming in the Mississippi River below the sewage treatment plant which had inadequate provisions for terminal disinfection (Rosenberg 1975). The strain of Shigella isolated from the river had the same antibiotic resistance as that isolated from shigellosis cases. It should be noted that the number of Shigella necessary to cause disease was on the order of 10- 100 cells (Bryan 1974).

The formation of chlorinated organics during disinfection occurs but at very low levels. The overwhelming majority of the chlorine applied to the sewage effluent ends up as chloride ion and about 10 to 20% becomes chloramines and N-Chloro compounds. Less than 0.1% of the chlorine dosed leaves the treatment plant as chlorinated organics (Jolley 1973).

Limited data has been available to demonstrate the effects of these compounds at the trace levels observed in the aquatic environment. The formation of trihalomethanes during chlorination of drinking water has been observed, and concern has often been noted for the presence of these compounds in sewage effluents. Figure 3 shows the formation of chloroform during the chlorination of trickling filter effluent to and beyond breakpoint. Less than 50 mg/liter of chloroform are formed at the breakpoint chlorine dose. The 100 g/liter maximum level suggested for drinking was exceeded only after a chlorine dose of 120 mg/liter, 40 mg/liter beyond breakpoint. Conventional chlorination of sewage effluent is accomplished with chlorine dosages of less than 20 mg/liter. At this level of chlorine application, little chloroform was formed (dashed curve; open points). Free chlorine quickly reacts with ammonia to form chloramines, which react very slowly to form trihalomethanes.

Page 77

140

120

100

o> E - 80

1 T3 "55 £ 60

« c 'C o o 40

20

CHCI 3/ /

/

140

120

100

o

■80 jP

60 J

40

20

0 20 40 60 80 100 120 140

Chlorine dose , mg / I

Figure 3. Formation of chloroform during the chlorine breakpoint for trickling filter effluent at room temperature for 30 minutes.

/

Page 78

SUMMARY

While there is still considerable debate on the transmission of enteric disease by contact recreation, recent, observed epidemics and epidemiological studies tend to support the route of transmission of disease.

Sewage disinfection effectively reduces the numbers of disease-causing microorganisms in the effluents of wastewater treatment plants oahd minimizes the dissemination of these agents in the receiving waters. The public health benefits • of sewage disinfection far outweigh the available field evidence to support massive environmental damage and generation of significant levels of carcinogens. In fact, the levels of trihalomethanes found during sewage chlorination are lower, than those found in drinking water since the combined, species of chlorine formed rapidly after the addition of chlorine react very slowly to yield trihalomethanes. Certainly prudence would dictate that more information and careful consideration be given to the health implications before current sewage disinfection practices are tampered.with.

Page 79

REFERENCES

Brezenski, F.T., Russomanno, R. and DeFalco, P. Jr. The Occurrence of Salmonella and Shigella in Post- Chlorinated Sewage Effluents and Receiving Waters. Health Laboratory Science, 2 (l):40-47, 1964.

Bryan, F.L. Diseases Transmitted by Foods Contaminated by Wastewater. In: Proceedings, U.S. Dept. HEW, Public Health Service. 1974.

Cabelli, V.J., Dufour, A.P., Levin, M.A., and McCabe, L.J. The Development of Criteria for Recreational Waters. In: Discharge of Sewage from Sea Outfalls, A.L.H. Gameson, ed. Pergamon Press, New York, 1975a. pp. 63-73.

Cabelli, F.J., Dufour, A.P., Levin, M.A., McCabe, L.J. and Habermann, P.W. Relationship of Microbial Indicators to Health Effects at Marine Bathing Beaches. Presented at the Annual Meeting of the Am. Publ. Health Assn. Chicago, 111. 42 pp. 1975b.

Cabelli, V.J., Dufour, A.P.,Levin, M.A., and Habermann, P.W. The Impact of Pollution on Marine Bathing Beaches: an epidemiological study. In: Soc. Limol. Oceanogr. Spec. Symp. 2:42 4-432.

Cabelli, V.J., Indicators of Recreational Water Quality. In: Bacterial Indicators/Health Hazards Associated with Water, A.W. Hoadley and B.J. Dutka, eds. Am. Soc. Test. Mater. Tech. Publ. 635, American Soc. for Testing and Materials, Philadelphia, 1977. pp. 222- 238.

Comptroller General of the United States. Unnecessary and Harmful Levels of Domestic Sewage Chlorination Should be Stopped. Report to Congress, U.S. General Accounting Office, CED-77-108, 1977.

Goldfield, M. Epidemiological Indicators for the Transmission of Viruses in Water. In: Viruses in Water, G. Berg, A.L. Bodily, E.H. 'Lennette, J.L. Melnick and T.G. Metcalf, eds. APHA, Washington, 1976.

Jolley, R.J. Doctoral Dissertation in Ecology, ORNL Oak Ridge, TN.

Kempelmacher, E.H., vanNoorle Jansen, L.M. Salmonella - Its Presence in and Removal from a Wastewater System.

Page 80

Water Pol. Control Fed. 42:2069-2073.

Kruse', C.W., Olivieri, V.P. and Kawata, K. The Enhancement of Viral Inactivation by Halogens. Water and Sewage Works, 118(6):1870193, 1971.

Kruse1, C.W., Kawata, K., Olivieri, V.P. and Longley, K.E. Improvement in Terminal Disinfection of Sewage Effluents. Water and Sewage Works, 120(6):57-64, 1973.

Moore, B. A Survey of Beach Pollution at a Seaside Resort. J. Hyg., Camb., 52:71, 1954.

Moore, B. Sewage Contamination of Coastal Bathing Waters. Bull. Hyg. 29:689, 1954.

Mosley, J.W. Transmission of Viral Diseases by Drinking Water. In: Transmission of Viruses by the Water Route, G. Berg, ed. Interscience Publishers, New York, 1967. p.5.

Naparstek, J.D., et al. Virus Removal in an Activated Sludge Plant. Water and Sewage Works, Ref. No. 16, 1976.

Olivieri, V.P., Donovan, T.K. and Kawata, K. Inactivation of Virus in Sewage. J. Sanit. Eng. Div. Amer. Soc. Civil Eng., 97:SA5:661.

Phelps, E.B. The Disinfection of Sewage and Sewage Filter Effluents. Water - Supply Paper 229, U.S. Geological Survey, Department of the Interior, Washington, D.C.

Rosenberg, M.S., et al. Transmission of Shigellosis by Swimming in a Contaminated River. EPA-75-18-2, Public Health Service, CDC, Atlanta, Ga., March 18, 1975.

Sherman, V.R., et jal. Virus Removals in Trickling Filter ' Plants. Water and Sewage Works, Ref. No. 36, 1976.

Stevenson, A.H. Studies of Bathing Water Quality and Health. Am. J. Public Health, 43:529-538.

Walsh, T. and Fincham, M.W. Understanding Spat Set, Maryland Sea Grant 4:4-6, 1981.

Page 81

RESPONSES TO QUESTIONS ASKED BY MR. GARNETT

Catherine I. Riley Maryland House of Delegates

(Submitted July 1981)

I will attempt to answer Dr. Garnett's questions.

la. There are some old stormwater drainage systems in my county which discharge directly into the septic system. Therefore, if the flow is not huge, there is some treatment. If the flow is great, even sewage effluent is undertreated due to inability to handle massive flow. However most newer systems are separate and stormwater runoff drains directly into bodies of water.

b. There is recognition that runoff from agricultural lands results in fecal effluent and chemical pollution entering bodies of water. There have been attempts to increase awareness of the significance of these non-point sources. I am unaware of any meaningful methods of reducing the flow other than holding ponds.

However, I believe that the U.S. philosophy regarding sewage effluence has always established human waste as the more significant percentage, and thus its treatment is of the higher importance.

2. Given the extremely large doses of chlorine the Bay is subjected to on a daily basis, it seems highly improbable that significant levels of chlorine compounds do not exist. Improved detection techniques, I feel, would disclose the levels of concentration. The over 6 tons of chlorine injected daily must be concentrating somewhere! Therefore reduced input of any halogens should result in improved quality of the Bay.

Evelyn Hailey Virginia House of Delegates

(Submitted July 1981)

Mr. Garnett's questions are most challenging. Virginia has encouraged a system of voluntary "best management practices" in dealing with storm run-off and non-point source pollution. He, Mr. Garnett, makes a very good point with his

Page 82

questions. I suppose the main concern comes from the need to appear to be protecting consumers of raw shellfish. As you know, the Health Department has a strong Shell Fish Sanitation Program that tests the water constantly to reduce the chance of contaminated shell fish reaching the market place.

William M. Eichbaum Assistant Secretary for Environmental Programs

Maryland Department of Health and Mental Hygiene (Submitted August 1981)

I have given some thought to the questions posed by Mr. Gamett.

Non-point runoff provides a significant source of pollution in river and estuarine systems. Studies done on the presence of disease organisms in urban stormwater have shown that although pathogenic microorganisms were present, the levels were low suggesting a minimal risk. Sewage effluent, on the other hand, represents the collected wastes of human populations and has the highest concentration of disease producing organisms, as human beings are the primary reservoir of disease trans- missible to other humans. Animal wastes represent a potential health risk of several orders of magnitude less than human wastes. Stormwater, even with the addition of some sewage overflow, represents a»lesser risk because of the dilution contributed by runoff. It is still a sound public health practice to attack pathogens at the point in which they occur in the largest concentration before they enter the environment. That point of attack is at the sewage treatment works.

In areas where sewage constitutes a large portion of the stormwater runoff, the best way to address the problem is not to disinfect the stormwater. The solution lies in the separation of sewage and stormwater through the deletion of combined sewers and the resolution of infiltration and flooding problems. Our current Construction Grants Program is directed, in part, toward these objectives.

Chlorine is a highly reactive substance which combines^ readily with organic materials to form many compounds. It is an established fact that it is extremely difficult to detect low levels of chlorine in an estuarine environment. This inability to detect low levels severely hampers enforcement actions as well as in situ studies. Although some organisms may have the ability to concentrate chlorine compounds, the levels are generally at the very limits of our ability to

Page 83

measure. The lack of recognized standard methods of detection and the low levels involved prevent the establishment of reliable monitoring programs. Reviews of recent research indicate that it is difficult to conclude that these low levels involved prevent the establishment of reliable monitoring programs. Reviews of recent research indicate that it is difficult to conclude that these low levels of chlorine compounds have any adverse affect. However, laboratory work would seem to indicate that it is desirable to minimize the discharges of chlorine where possible. We are working to this end. To date, no objective methods have been recommended or established. We shall continue to stay abreast of the latest information and technology and will develop monitoring programs as technology permits.

I trust that I have answered these questions in the depth which you required. The issue of chlorine and its impact on the Bay will not be easily resolved, but with the constant exchange of information progress can be made.

Page 84

SEWAGE CHLORINATION: "STATUS QUO"

C.M. Sawyer

Bureau of Wastewater Engineering Virginia State Health Department

Richmond, Virginia 23219

INTRODUCTION

A variety of pathogenic organisms shown in Table 1, are normally present in domestic wastewater. For maximum public health protection, the numbers or density of pathogens is assumed sufficient to cause a reasonable probability of infection upon ingestion of even highly diluted sewage. Out- breaks of waterborne diseases in the United States are in- frequent, but reported cases of Shigella and Salmonella illnesses, as well as gastroenteritus related to enteric viruses, have occurred among swimmers; and many cases of infectious hepatitis seem to be related to the consumption of raw shellfish. The health significance of waterborne pathogenic protozoa and fungi is relatively unknown, although limited outbreaks of amebic caused diseases have occurred.

Adequate water quality criteria can be maintained and health protected, if pathogens are removed or destroyed by physical or chemical means prior to wastewater discharge. Thus natural die-off and dilution would eliminate the possibility of contact with an infective dose.

Organisms

I. BACTERIA

Salmonella (Approx. 1700 types)

Shigellae (4 species)

Escherichia coli

Disease

Typhoid Fever Salmonellosis

Shigellosis

Gastroenteritis (enteropathogenic types)

Reservoir(s)

Man, domestic and wild animals and birds

Man

Man, domestic animals

Vibriod Comma Cholera Man

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Organisms

II. ENTERIC VIRUSES

Enteroviruses

Polioviruses

Coxsackieviruses

Echoviruses

Rotavirus (Reovirus)

Parvovirus-like agents (Norwalk)

Hepatitis A virus

Adenoviruses

III. PROTOZOAN

Entamoeba histolytica

Giardia lamblia

Disease

Gastroenteritis, heart anomalies, menigitis, others

Polio

Gastroenteritis

Gastroenteritis

Gastroenteritis

Gastroenteritis

Infectious Hepatitis

Respiratory disease, con- junctivitis other

Amebiasis

Giardiasis

IV. HELMINTHS

Nematodes (Roundworms) Ascaris lumbricodies Ascariasis Ancylostoma

duodenale Necator americanus Enterobius vermicularis

(pinworm)

Ancylostomiasis Necatoriasis

Trichuris trichiura (whipworm)

Cestodes (Tapeworms) Taenia saginata

(beef tapeworm)

Enterobiasis

Trichuriasis

Taeniasis

Reservoir(s)

Man, possibly lower animals

Man

Man

Man

Man, domestic nimals

Man

Man, other primates

Man

Man

Man, domestic and wild animals

Man, swine?

Man Man

Man

Man

Man

Page 86

Organisms

Taenia solium (pork tapeworm)

Hymenolepis nana (dwarf tapeworm)

Disease

Taeniasis

Taeniasis

Reservior(s)

Man

Man, rat

TABLE 1: Pathogenic Organisms That May be Present in Sewage from U.S. Communities.

Wastewater can be disinfected by any physical or chemical means which removes, or reduces to safe levels, the hazards of infectious disease transmission in receiving waters. A number of disinfectants can be used to destroy, or inactivate to some degree, microbiological organisms.. Disinfectants attack the individual cell in several ways which include destruction of the cell wall or membrane, denaturing of cell protein or enzymes, and disruption of nucleic acids. A reliable disinfectant must be capable of destroying the disease-producing characteristics of potentially pathogenic microorganisms, such as vegetative bacterial cells, bacterial spores, viruses, protozoa and protozoan cysts. In addition, a practical wastewater disinfectant should possess the following characteristics:

1. Accomplish acceptable disinfection within a reasonable time or contact period.

2. Remain an effective disinfectant within an expected range of variations in the physical-chemical characteristics of wastewater flows, such as temperature, pH, organics, etc.

3. Be available at reasonable costs.

4. Be safe to handle and technically and economically convenient to apply in a controlled manner to wastewater flows.

5. Produce a detectable or easily determined concentration in the treated effluent which provides proper disinfection as noted by indicator organism tests.

6. Not produce compounds or reaction products in wastewater at levels which would produce toxic effects in the receiving waters.

A number of factors may establish the performance efficiency of a particular disinfection process. Microorganisms have different levels of resistance to germicidal agents, which vary

Page 87

with the physical, chemical, or biological nature of the wastewater. Wastewater characteristics such as temperature and pH can influence both chemical and biological activity. Organic material in the wastewater may react with the disinfectant and lower its germicidal action, while other solid fractions may act as a shield to protect the organism. Microorganisms may exist in resistant forms, such as spores or cysts, or they may persist in masses or clumps of cells in which internal microorganisms are protected by surrounding cells.

Providing adequate exposure to accomplish disinfection may also depend on the method of application and the hydraulics of the flow through the contact unit. Uniform and rapid dispersion of the disinfectant into the wastewater must be achieved for efficient disinfection. Hydraulic inefficiencies, such as high velocity currents, can severely limit the contact between cells and levels of disinfectants which will inactivate the organism.

DISINFECTION STANDARDS

Disinfection efficiency is commonly determined by biological enumeration tests for indicator organisms. The tests assume that a_significant reduction in indicator organisms parallels a similar reduction in pathogenic species. Indicator organisms are thus used to quantify the probability of contact with an infective dose of a waterborne pathogenic species.

Acceptable limits for coliform density in certain waters have been established for maximum water quality protection. Proposed most probable number (MPN) standards of 1000 total coliforms per 100 milliliters and 200 fecal coliforms per 100 milliliters have been previously adopted for recreational waters, based on limited epidemiological data. A limit of seventy total coliforms and fourteen fecal coliforms per 100 milliliters has been established as the maximum median values for shellfish growing waters.

The enactment of P.L. 92-500 had the effect of requiring continuous disinfection of domestic wastewater effluents for maximum protection of human health. The Environmental Pro- tection Agency (EPA) promulgated effluent limitations for fecal coliform bacteria in section 133.102 c of 40 CFR Part 133 which required the following minimum levels of disinfection:

1. "The geometric mean of the values for effluent samples collected in a period of 30 days shall not exceed 200 per 100 milliliters (FC-MNP-200).

2. The geometric mean of the values for effluent collected

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in a period of seven consecutive days shall not exceed 400 per 100 milliliters."

In order to attain EPA disinfection standards, a separate unit process of disinfection is necessary, as secondary treat- inent alone seldom accomplishes more than a ninety percent total coliform reduction. Since chlorine was the only establish wastewater disinfectant in 1972, the use of chlorination was greatly encouraged. Although the toxicity problems resulting from chlorine residuals were well documented, little consideration had been given to optimizing chlorination techniques to protect aquatic organisms. Laboratory studies have demonstrated that chlorine residuals as low as ten parts per billion are toxic to certain aquatic life. The health significance of halogenated organics isolated from chlorinated wastewaters is not known, however, the measured levels in existing discharges are apparently insignificant.

In light of these developments, the Environmental Pro- tection Agency has adopted revisions to its secondary treatment regulations, in which the effluent limitations for fecal coliforms are deleted and disinfection criteria are based on water quality standards.

However, chlorine is essentially the exclusive disinfectant used for wastewater treatment because chlorination meets disinfection standards more economically than any alternative. Thu a competitive market exists for supplying chlorine, chlorination equipment and monitoring units for the application and control of this treatment process.

CHLORINE.CHEMISTRY

Chlorine gas is soluble in water (7,160 mg/1 or 61 pounds per 1000 gallons, at 200C and 1 ATM) and hydrolizes rapidly to hypochlorous acid (H0C1). At the nearly neutral pH of most municipal wastewaters, the hydrolysis is virtually complete. Other halogens, such as bromine and iodine, also form hypo- halous acids as shown in Table 2. Hypochlorous acid can ionize to yield a proton (H+) and the hypochlorite ion (0C1~), dependin on wastewater pH; but at pH values below 7.5, H0C1 predominates briefly as the primary form of chlorine disinfectant. Hypochlor acid and the hypochlorite ion are referred to as free available chlorine.

Secondary effluents, depending on temperature and the type of biological process, typically contain five to fourteen mg/1 of ammonia nitrogen; and the reaction between ammonia and free available chlorine produces combined available chlorine in the form of monochloramine (NH2CI) and dichloramine (NHCI2), also depending on the wastewater pH. At pH values below 7.5

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themonochloramine predominates. Chloramines are not as efficient disinfectants as free available chlorine as shown in Table 3. Hypochlorous acid may also react with wastewater constituents to form organic chloramines which possess little or no disinfecting power. The sum of the concentrations eventually formed of free and combined available chlorine is referred to as the total residual chlorine (TRC).

1. Cl2 + H20 = H0C1 + H+ + Cl"

BrCl + H20 = HOBr + H+ + Cl~

2. HOX = OX" + H+

3. HOX + NH3 = NH2X + H20

hox + nh2x = nhx2 + h2o

HOX + NHX = NX3 + H20

Note: X Represents Either Cl or Br

TABLE 2. Reactions of Chlorine and Bromine Forms in Water

Chlorine may be purchased as liquified chlorine gas or as liquid or dry hypochlorite. Containers of liquid chlorine under high pressure vary in size from 100 pounds to one ton. Chlorine gas is less expensive and demonstrates more stable disinfecting power when stored for lengthy periods than hypochlorites. Liquified chlorine gas is extremely dangerous to handle. En- closures containing chlorinators or liquid storage containers must be well-vented, and a gas-tight separation must be provided between the chlorination equipment and other occupied areas.

Chlorine gas is usually produced by electrolysis of brine îth a by-product of sodium hydroxide. Sodium hypochlorite (NaOCl) can be produced by recombining the gas with sodium hydroxide._ Sodium hypochlorite is available as a liquid concentrate with approximately fifteen percent chlorine, but the ten percent trade strength is more economical. A hypochlorite solution should not be subjected to extreme temperatuires Storage of NaOCl at 75 F will result in a fifty percent loss of activity in 100 days. Calcium hypochlorite (Ca(OCl)o) is available in dry granular form, which can be dissolved into * "ater solution for disinfection use. High test hypochlorite (.HTH; may contain as much as seventy percent available chlorine.

/

J Page 90

TARGET ORGANISM

DISINFECTING AGENTS

"RELATIVE EFFICIENCY CONDITIONS

ENTERIC BACTERIA

HOBr, HOC1, I2

I2 in NH4C1, NH2Br

and NH2C1

OCX" and HOC1

I2, HOC1, HOBr

HOCl - HOBr >12 25 c., 10 min

I2 > NH2Br >

nh2ci

pH 7.5, 0oC. 8mg/l dose

HOC1 > OC1" 5 0C., pH 6.0

HOCl> HOBr> I2 pH 7.0, 3-40C

ENTERIC VIRUSES

I2, HOC1, HOBr

I2 HOC1

HOC1, OCX"

HOC1 - HOBr >I2 250C., 10 min

5 "C.

5 "C.

I2 >> HOCI

OCX" > HOCI*

BACTERIAL VIRUSES

I2 in NH4C1, NH2Br

and NH2CI

HOCX, OCX'

I2 >> NH2Br

nh2ci

HOCX > OCX"

pH 7.5, 0oC,

5 0C.

PROTOZOAN CYSTS

I2, HOCX, HOBr

I2, HOBr, and HOCX

in H20 with glycine

and NH4CI

HOCX =HOBr= I,

I2 > Br >CX

(Mixture of forms)

& I2 > CI2> Br2

25 0C. , X0 min

pH 6.0

pH 8.0

^Reported experimental error due to sensitizing of virus, making it more susceptible to OCX .

TABLE 3: Comparison of the Relative Disinfection Efficiency of Certain Halogen Compounds

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Hypochlorous acid is immediately formed in any diluted hypochlorite solution in which the pH approaches 7.0.

PROCESS OPERATION

A conventional chlorination system usually consists of a supply system, a dosage metering system, a solution discharge system and control equipment. The supply system includes weighing scales to monitor chlorine usage and a gas withdrawal system of valves and gages for liquid chlorine containers. The chlorinator features a pressure-vacuum regulating valve to reduce the supply pressure of the chlorine gas to a negative (vacuum)level. The gas flow through the chlorinator can be fine-tuned by adjustment of a metering orifice, which is in- line with a vacuum differential regulating valve. Gas flow from the chlorinator passes into an injector, where it is mixed with an outside supply of water or treated wastewater. The chlorine mixture is then pimped through a diffuser mechanism into the influent to the chlorine contact chamber.

Hypochlorite systems usually feature gravity or pumped feeding of the chlorine solution formed from the hypochlorite. The feed rate can be controlled by valves or metering pumps. Dry tablets hypochlorinators can be used to disinfect small flows (10,000 gallons per day (gpd) or less). The tablet chlorinators contain stacked columns of tablets which dissolve at a controlled rate as the contact tank influent passes around the tablet, releasing hypochlorous acid. As the bottom tablet dissolves, the tablet immediately above it drops into place within the flow depth established by a flow control weir. On-site generation of hypochlorite is infrequently used to treat larger flows, as it is a more expensive process than the use of liquid chlorine containers.

Most chlorination systems feature an open-loop, flow proportional control, in which the gas flow through the chlorinator metering orifice may be increased or decreased in direct proportion to the contact tank influent flow rate. By adding a chlorine residual analyzer to signal and feedback the residual changes in the contact tank effluent, a closed loop system can be developed. The residual analyzer most often utilized is an amperometric device, which requires constant attention to insure proper operation. The residual feedback signal can be used to increase or decrease the chlorine feed rate through direct adjustment of the differential- regulating valve on the chlorinator. The chlorinator compounds the residual signal with the flow rate signal to achieve a more flexible and closely controlled operation. More exact chlorination control is obtained by placing a second analyzer in the control system to monitor upstream chlorine residuals in the chlorine contact tank and by using that signal to trim

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the chlorine feed rate up or down. This cascade control system develops a quick response to residual fluctuations caused by changes in wastewater quality.

Many studies indicate that uniform injection and intense mixing of the chlorine dose, followed by adequate detention within a contact basin, is more important to disinfection efficiency than is an arbitrary increase in chlorine dosage. Re- sults of in-plant modifications demonstrate that uniform dispersion of chlorine, with violent mixing upstream of the contact basin, will increase disinfection efficiency without an increase in chlorine dosage. A recent study conducted by Hampton Roads Sanitation District personnel provided data indicating that turbulent diffusion of chlorine into the contact chamber would increase disinfection efficiency and decrease chlorine requirements for off-quality (45 mg/1 BOD) secondary effluent.

Uniform dosage application may be attained with pumps, grid injectors and perforated plates which disperse the dose within the wastewater flow. Apparently, uniform injection and rapid mixing of the chlorine dose exposes a larger number of microorganisms to the disinfectant. Upstream mixing may be provided by.hydraulic pumps, step down drops, tubular reactors, and high velocity flows in pipeline bends. Adequate contact to residual chloramines is necessary for inactivation of cells and is extremely important to a chlorination-dechlorination process where break-point chlorination is not used. Similar problems related to adequate exposure or contact times may exist with other alternate disinfection processes. Many contact tank designs are subject to severe short-circuiting effects which allow flow to leave the basin after short residence periods. Contact basins should be designed to achieve a plug flow condition for maximum flow retention. Horizontal baffles or a series of longitudinal end-around baffles provide extended retention times and prevent short-circuiting caused by thermal currents. A flow path length to tank width exceeding fifty to one provides protection against short-circuiting.

AQUATIC TOXICITY

Chronic toxicity effects, which may impair the normal functions of aquatic life, have been observed in fish continuously exposed to extremely low levels of TRC (0.01 mg/1 or less). Studies of fish, caged below wastewater outfalls, indicate that TRC levels above 0.01 mg/1 and 0.002 mg/1 can have adverse effects on freshwater populations of warm and cold water fish, respectively. In addition, limited data suggest that TRC levels above 0.01 mg/1 may pose a serious hazard to marine and estuarine life.

In the spring of 1973 and 1974, significant fish kills

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were documented near the mouth of the James River in the Common- wealth of Virginia. Residual chlorine from the effluent discharges of the James River and Small Boat Harbor sewage treatment plants was considered the most likely agent causing the fish mortalities. For this reason the Governor of Virginia established a select inter-agency task force to direct a study of chlorine toxicity and alternative disinfectants.

Comparative studies of the disinfection efficiencies and relative toxicities of chlorine and bromine chloride were begun in May 1977. The results of those studies were published as a final report in October 1978. A summary report of the select inter-agency task force was released in October 1979 and was followed by a special report entitled: "Production of Halogenated Organics During Wastewater Disinfection, December, 1980." These reports have been distributed by the Virginia Marine Resources Commission, Newport News, Virginia. In reviewing the results of the chlorine toxicity studies conducted at the James River sewage treatment plant, the Virginia State Health Department found no evidence that chlorine residuals, originating from effluent discharges from the James River and Small Boat Harbour facilities, were the principal causes of the 1973 and 1974 fish kills.

The total amount of chlorine utilized at the James River plant averaged about 1100 pounds per day with a daily flow volume of nine million gallons in 1973. Beginning in 1975, chlorine use at this plant has been reduced approximately 257o during each spring, which purportedly has contributed to the absence of any documented fish kills. Since 1975, however, the total amount of chlorine used at the James River plant has gradually increased to a present average usage of approximately 2000 pounds per day with a daily flow volume of thirteen million gallons. Thus, the chlorine usage has nearly doubled since 1975, but no large fish kills have been reported since that time.

The Virginia Institute of Marine Science (VIMS) has conducted a chlorine residual monitoring program in the James River in the vicinity of the treatment plant outfall. Field tests conducted on June 30, 1974 by VIMS produced data that indicated residual chlorine levels of 0.1 to 0.7 parts per million were present in the boil of the plant effluent discharged into the James River. These results have not been verified in any later field studies using proven analytical methods. Current residual chlorine levels monitored at the same location indicate a value of 0.03 parts per million, which rapidly drops to a non-detectable level at a distance of one hundred yards away. The flow-through bioassay studies of juvenile spot exposed to diluted wastewater conducted by VIMS indicated that residual chlorine was not toxic at expected in-stream levels. The 96-hour LC50 for residual chlorine was

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0.23 mg/l.

The results of the disinfection studies conducted under the auspices of the Chlorine Task Force lead to the following conclusions:

1. Chlorine-produced oxidants (CPO) introduced into the James River from sewage treatment plants could not have been the major agents causing1 mortalities during the 1973 and 1974 spring fish kills. The strict seasonality of the events, unrelated to variations in disinfection practice at the plants, and the observed scoliosis (bent and broken backs), strongly suggest that other factors played a major role in the fish kills.

2. Although scoliosis was observed in many of the fish killed during the spring of 1973 and 1974, this effect has not been observed during any toxicity tests with halogens. Scoliosis is more likely due to exposure to sublethal levels of toxic substances. The presence of kepone in the James River, unknown at the time of the fish kills, strongly suggests that kepone may have contributed to fish mortalities.

3. Toxic effects of chlorination practices can be reduced or eliminated, while achieving adequate disinfection, through stringent control of thirty minute residuals and dilution rates. At present, a CPO level of 0.02 mg/l or less is believed acceptable at the discharge location to protect oysters and oyster larvae.

4. If detoxification of chlorinated effluents is necessary on a regular basis because dilution or management do not provide a suitable CPO level at the discharge site, the most economical alternative is dechlorination.

Studies of halogenated organics production during wastewater chlorination at the James River sewage treatment plant (JRSTP) indicated that insignificant quantities of chlorinated organics were produced. Chloroform, the principal product of chlorination during these studies, had an average concentration in the effluent of 8.0 parts per billion compared to 4.0 parts per billion in the untreated sewage influent. The final report concerning these studies states:

"If one assumes that marine species have sensitivity to chloroform and bromoform similar to that of fresh water species, one would expect an LC50 between 1 and 100 mg/l. These concentrations are 10,000 to 1,000,000 times higher than the concentrations expected in receiving water immediately, adjacent to the JRSTP outfall."

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A study of oyster set in the Warwick River above and below the JRSTP was conducted by Dr. M.E. Bender, et. als., in 1978 in response to Virginia House Joint Resolution Number 162. The following conclusion was obtained:

"From the data available, which cover one complete oyster spawning season, no impacts on oyster set in the Warwick River due to chlorine releases from the James River Waste Treatment Plant were detected during the 1978 setting season.

PUBLIC HEALTH CONCERNS

As more in-field evidence is collected, it appears that the toxicity of chlorine residuals and chlorine-produced oxidant (CPO) is not as severe as initial laboratory studies had indicated. Implicating undetectable chlorine residuals with massive fish kills, based on limited evidence, and stating that chlorination has no impact on public health because sufficient epidemiological evidence supporting its benefits is not available seems somewhat contradictory. If limited evidence of toxicity is sufficient to ban chlorine residuals, then limited epidemiological data should be enough to support chlorine's public health benefits.

Much is said about the European practice of not disinfecting wastewaters, but little is said about the high counts of enteric viruses found in these waters and about the role natural immunity plays in prevention of disease outbreaks among those who come into contact with these waters. Our own disinfection practices have so restricted pathogens' access to' contact waters that a lack of widespread waterborne disease outbreaks has led to the false assumption that sewage polluted waters are safe.

Disinfection is the only conventional wastewater treatment operation which accomplishes significant virus removal. The shellfish and bathing beach industries in Tidewater Vir- ginia are too valuable to risk the damage which would result from an outbreak of bacterial or viral infections due to sewage contamination. The water quality in most Bay waters is much improved compared to the water quality which existed twenty years ago. During recent years no outbreak of waterborne illness has been associated with consumption of seafood or shellfish harvested from Bay waters. Everything possible should be done to keep this record intact.

The Virginia Department of Health concurs with the recommendations for wastewater disinfection in estuarine areas of the Commonwealth, as developed by the inter-agency task force on chlorine:

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"1. Chlorination of sewage effluents should be managed to yield a 2.0 mg/1 residual after 30-min. contact provided a 1:20 or greater dilution of effluent can be assured at the point of discharge. Such a dilution rate coupled with typical decay of CPO upon discharge will result in a CPO level of not more than 0.02 mg/1.

2. Dechlorination should be applied only to those sewage treatment effluents for which adequate dilution cannot be achieved to eliminate adverse toxic effects of CPO when chlorination practices are properly managed."

SUMMARY

Existing technology and economics now favor chlorination as the most practical means of disinfecting wastewater. Chlorination of wastewaters is effective in reducing the hazards of waterbome disease outbreaks, resulting from effluent discharges into recreational and food supply waters. This protection is part of a multiple-barrier concept which minimizes the possibility of public exposure to pathogenic organisms. Although chlorination can reliably meet present bacteriological standards for secondary treatment, some deficiencies and disadvantages are inherent in current practices. These include:

1. Low MPN counts may not correlate with adequate levels of disinfection. Other types of indicator prganism tests should be developed.

2. Interfering substances may limit the effectiveness of a given chlorine dose. A high level of pretreatment should be provided.

3. Chlorine residual levels and contact periods now employed for disinfection may not be adequately monitored and controlled. Well-trained and informed treatment plant operators are absolutely necessary.

Uncontrolled and indiscriminate use of chlorine for disinfection should not be permitted. In-plant modifications, which provide proper mixing of the influent and chlorine dose, and suitable contact periods with accurate residual monitoring, and control should eliminate many of the operational and toxicity problems associated with present chlorination practices. Alternate means of disinfection may possess certain advantages that favor their use in some instances, but a proper evaluation of the ecological health and resource trade-offs should precede the selection of any one method of disinfection.

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i

REFERENCES

Bender, M.E. , D.S. Haven, and H.D.. Sloan. 1978. "Report on the Effect of Chlorine on Oysters in the Warwick River", Virginia Institute of Marine Science.

Kennedy, G.D., N.E. LeBlanc, et. al. 1980. "Disinfection Efficiency of the Pentech Jet Diffusion Chlorination System." Hampton Roads Sanitation District Commission.-

LeBlanc, N.E., M.H. Roberts, and D.M. Wheeler. 1979. "Dis- infection Efficiency and Relative Toxicity of Chlorine and. Bromine Chloride - A Pilot Plant Study in an Estuarine Environment." Virginia Chlorine Task Force Report, Virginia State Water Control Board.

Martin, G.L. and Karl Shurr. 1979. "Effect of a Properly Loaded Sewage Lagoon on the Receiving Stream." Bowling Green Popular Press, Science Series B 149.

"Proceedings of the Conference on Microbial Health Considerations of Soil Disposal of Domestic Wastewaters," 1981. National Center for Ground Water Research, University of Oklahoma.

Roberts, .M.J., N.E. 'LeBlanc, N.E. Lee, et. al. 1980. "Pro- duction of Halogenated Organics During Wastewater Dis- infection". Special Report in Applied Marine Sciences and Ocean Engineering, No. 239.

Sawyer, C.M., "Industrial Wastewater Disinfection: Alternatives to Chlorine." Plant Engineering Magazine (to be published).

Sawyer, C.M. "Wastewater Disinfection - State of the ART Summary." 1976. Bulletin 89, Report for the Virginia Water Resources Research Center, VPI & SU, Blacksburg, Virginia. '

Venosa, A.D., Ed., 1978. "Progress in Wastewater Disinfection Technology." Proceedings of the National Symposium, U.S. EPA, Merl.

v ' White, G.C., 1978. "DISINFECTION OF WASTEWATER AND WATER FOR

REUSE. Von Nostrand Reinhold Company.

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DECHLORINATION OF WASTEWATER: STATE-OF-THE-ART DISCUSSION

David J. Greene

Maryland Environmental Service 60 West Street

Annapolis, Maryland 21401

While some residual chlorine may be aesthetically at- tractive and an indication of safety, it has become necessary to remove residual chlorine from wastewaters before discharge into a sensitive aquatic environment. Residual chlorine generally can be reduced to innocuous chlorides by most chemically active reducing agents. Not all of these reducing agents lend themselves to wastewater disinfection, but several dechlorination techniques are available.

Aeration may be used to drive out the residual chlorine, although extremely low residuals using this technique are not likely.

Activated carbon, under certain conditions, has been used to remove residual chlorine. Howeverc, high capital costs and maintenance often dissuade its use.

The most commonly used dechlorinating agents are members of the sulfite family with the most popular chemicals being sodium metabisulfite, sodium sulfite and sulfur dioxide. Sodium metabisulfite and sodium sulfite in powder form can be easily applied with a volumetric dry feeder or mixed into a solution and applied with a chemical feed pump.. By far the most popular dechlorinating method, sulfur dioxide is frequently used because of its low cost and ease of application. The equipment used for sulfonation is identical to that used for chlorination. This makes sulfur dioxide application easily adaptable in most wastewater facilities.

The chemical characteristics of sulfur dioxide gas have added to its popularity. Sulfur dioxide reacts with free chlorine and combined chlorine almost immediately. Sulfur dioxide in water rapidly forms sulfurous acid:

S02 + H20 ----> H2S03

The sulfite radical thus formed reacts with the chlorine compounds to form mainly sulfuric and hydrochloric acids in small quantities:

Free chlorine H2S03 + HOCl ---+ H2S04 + HC1

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Chloramine nh2ci + h2so3 + h2o nh4hso4 + HC1

The by-products of sulfonation, chlorides and sulfites, have not been shown to be toxic to fish at the levels encountered in wastewater dechlorination.

For 'SO2 application, most larger facilities utilize a feed forward type system with primary control based on flow and secondary control based on residual levels. This secondary control signal must be a feed forward rather than a closed loop, since many of the currently available residual chlorine analyzers are not capable of monitoring and controlling a dechlorinated effluent as shown in Figure 1.

FIGURE 1: Common Feed Control System

Injection of ,the sulfur dioxide occurs largely through diffusers; no contact chamber is needed because of the high solubility and reaction rate of the sulfur dioxide. A mixing chamber which completely disperses the sulfur dioxide solution is all that is. necessary. This can often be provided in an existing facility with little or no modifications.

To date, no adverse effects on water quality have been found. After dechlorination with SO2, the pH remains relatively unchanged as does the dissolved oxygen. However an increase in

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total coliform concentration has been consistently observed in dechlorinated effluents. This increase is probably due to a build-up of bacterial growth in the dechlorination 1

system. These growths, or slime, are ideal sites for coliform attachment and growth, given the nutrients and moderate temperatures of the wastewater.

In review, advantages of sulfur dioxide dechlorination are mainly its low capital and maintenance costs. In addition, its feed system is identical to chlorine's, which treatment facility operators are accustomed to using; and no significant physical or chemical degradation of the effluent has been found yet.

Disadvantages include the addition of another chemical to the environment. At present, there are no methods to analyze the sulfite radicals formed in water. Consequently, sulfur dioxide must be controlled by measuring the chlorine residual. -Excessive overdosing is obviously going to occur, especially in small wastewater facilities where the feed rates are controlled by hand.

\

In conclusion, an optimized chlorinated-dechlorination set-up can be a cost effective solution to toxic chlorine discharge .

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OZONE: ALTERNATIVE TO CHLORINE

Bruce B. Burns, P.E. Gannett, Fleming, Corddry and Carpenter, Inc.

Village of Cross.Keys West Block, Suite 345

Baltimore, Maryland 21210

In recent - years, the use of chlorine as a disinfectant has been subjected to a great deal of criticism. In the area of wastewater treatment, criticisms primarily concern the discharge of sewage effluents with a high residual chlorine level to receiving streams. Because many believe that chlorine has a severe impact on the aquatic environment, engineers and environmentalists have begun to look for effective and economical alternatives to chlorine.

Using ozone as a disinfectant is. not new. The first recorded use of ozone was in Holland, where it was used to sterilize drinking water from the Rhine River. In 1898, Paris began using ozone for the disinfection of river water at the Saint Maur facility, which was the first major ozone installation in the world.

Since that time, ozone gained acceptance - in Europe and other areas of the world. Ozone might now be used universally as a disinfectant of water had it not been for World War I. During the war, the United States discovered, as a byproduct of some of their research, an inexpensive process for the manufacture of chlorine gas. Thus, in this country, ozone never made any substantial impact until the mid 1970's. In Europe, however, ozone has remained the chosen method of disinfection. Estimates indicate that more than 1000 installations are now using ozone in more than twenty different countries, including France, Germany, Norway, Russia, Holland and Canada. In France alone there are more than 100 installations .

In the early 1970's, engineers in this country began to recognize that ozone could be a viable alternative to chlorine as a disinfectant of wastewater effluents. To gain acceptance in this country, a transition had to be made from using ozone to disinfect drinking water to using it for the disinfection of sewage effluent. In contrast, European basic policy has been not to disinfect wastewater effluents.. Thus, although ozone as a disinfectant is not new technology, using it for the treatment of wastewater was a new application and some problems had to be overcome.

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As with any new system or process, many of the early ozone installations in this country had operational difficulties. For example, engineers need to be educated concerning the use of ozone and its properties, such as material compatibility, equipment maintenance requirements, and process limitations. There have also been application problems at many of the plants constructed in this country which will be addressed later in this paper. However, as these problems are being addressed and corrected, ozone is becoming an effective, reliable disinfectant.

Ozone is an unstable gas which boils at minus 112 degrees C at atmospheric pressure, is partially soluble in water, is about ten times more soluble than oxygen, and has a characteristic penetrating odor readily detectable at concentrations as low as 0.01 to 0.05 parts per million. A powerful oxidant, it has an oxidation potential of 2.07 volts. In an aqueous solution, ozone is relatively unstable, having a half-life of about twenty to thirty minutes. If there are oxidant-demanding materials present in solution, the half-life of ozone in such solutions will be even shorter. It has the highest practical, commercially available chemical activity. Ozone is also a clean water treatment chemical, effectively treating or disinfecting wastewater without creating sludges or adding dissolved solids. Any unreacted ozone in treated effluent breaks down readily to dissolved oxygen which is beneficial to aquatic life. Ozonation, as normally practiced, produces no known long-lived toxic residuals, unlike chlorine, which reacts with trace organic residues to form chlorinated hydrocarbons and with ammonia to form chloramines.

There is only one method to produce ozone in commerical quantities. Dry oxygen-bearing gas passes through a pair of electrodes; energy is added to two electrodes and an arc is created across the gap between the electrodes. The oxygen- bearing gas passes through this gap where oxygen molecules are dissociated to atomic oxygen, which then recombine with other oxygen molecules to form ozone.

One of the problems associated with the generation of ozone is that the basic method of production is inherently inefficient. Only about ten percent of the energy supplied is' used to make ozone. The remainder is lost as light, sound, and primarily heat. Unless heat is removed efficiently, the ozonator gap (the space between the two electrodes) acts as an oven and high temperatures build up in the discharge space and at the dielectric surfaces. If temperatures are allowed to build up, ozone yield will suffer since decomposition of ozone is very temperature sensitive. Therefore, an efficient method of heat removal is essential. When a clean, dry, oxygen- rich gas is fed to the ozone generator and an efficient method of heat removal is available, then ozone can be successfully

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produced under optimum conditions.

Ozone treatment systems can be designed in several basic configurations, using either air or oxygen as the feed gas to the ozone generators. Air systems are generally of a once- through design in which the ozone bearing gas is passed once through an ozone contactor and then vented to atmosphere. An oxygen system can be an integrated one in which the oxygen is passed through the ozonator, once through the ozone contactor, and then delivered to another treatment process, such as secondary wastewater treatment, where the remaining oxygen in the process stream can be utilized. Thus, the gas in the system passes once through the ozone generators and contactors and is integrated into another treatment process. An alternative to this system is to recycle the oxygen within a closed loop to the ozonators.

The typical, well-designed air system will require, at a minimum, a feed compressor, a gas dryer package, ozone generators, an ozone contacting system, an ozone decomposition device, and a vent compressor. Various heat exchangers, electric heaters, aftercoolers, installed spares, and other . miscellaneous equipment may also be required, depending upon the specific design configuration.

The ozone contacting system is probably the most critical part of an ozone system design. Ozonation should be able to disinfect a wastewater typically containing 10 to 30 mg/1 of suspended solids, 10 to 30 mg/1 of BOD and COD, and less than 200 fecal coliforms per 100 ml. Ozone, as a strong oxidant, cannot differentiate among all the components with which it might react, when applied to the complex wastewater mixture described above. There will be, of course, a natural differentiation with respect to the kinetics of particular reactions; but thermodynamically, ozone has the potential to react with essentially all of the organic components and many of the inorganic components of a wastewater which has had secondary treatment. While selectively disinfecting secondary effluents is difficult, it is possible to achieve some selectivity in the design of a contact system to favor the disinfection process at the expense of other possible reactions which might consume ozone.

Since the excellence of ozone in terms of low dose and rapid disinfection of bacteria and viruses is well known, its problem then is one of economics, not efficacy. How can secondary effluent disinfection be achieved with the relatively low doses predicted from drinking/clean water experience? Can an ozone system be designed to favor the disinfection reaction and minimize ozone consumption by other reactions which occur in wastewater?

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For all practical purposes, the ozone disinfection reaction may be considered instantaneous. If the microorganisms and the ozone are brought together, disinfection occurs extremely rapidly. Similarly, from a practical engineering point of view, some particular oxidation reactions of ozone are extremely fast--so fast, that they compete for the ozone applied for disinfection. Many other reactions are much slower. In general, these reactions are not a concern unless the disinfection reactor is designed with long contact times, where the probability of ozone consumption by chemical reaction rate, limited reactions and auto-decomposition becomes significant.

Many of our early ozone systems had problems associated with the ozone contactors. The ozone utilization rate for some early U.S. systems was as low as fifty percent. The ozone molecules were being put into the wastewater; however, the dispersion techniques were poor. In order to have effective disinfection, the ozone molecules must come in direct contact with the bacteria and microorganisms.

Any ozone contacting system must be designed specifically for the problem to be solved, and those items which will interfere with the desired disinfection must be identified and considered during design. Most systems designed today are designed for a minimum ozone utilization of ninety percent, given no short circuiting and a typical contact time of fifteen minutes. If such factors as diffuser type, size and porosity, diffuser arrangement, mixing, baffling, wall effects, and construction materials are properly taken into account in the design, complete disinfection will occur.

Like chlorine, ozone can be harmful if it comes in direct contact with the human body. Proper safety considerations must be designed into any system. Ozone detection devices should be installed in any confined area where there is the potential for an ozone gas leak. There are essentially no other dangers to operating personnel.

Some of the major advantages of using ozone over chlorine include:

1. Short half-life, thus, safer to use. 2. High dissolved oxygen concentrations result in the

effluent. 3. Elimination of potentially dangerous hydrocarbons in

the receiving water. 4. No known toxic substances formed. 5. On-site generation facilities eliminates hauling expenses. 6. Oxone is compatible with certain wastewater treatment

processes which could mean substantial savings in operation costs.

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There are two ina-joir disadvantages of ozone. First, ozone generation is very energy intensive and can only be produced by a direct conversion of electricity. However, this problem is hsing minimized as the manufacturers of ozone equipment develop more efficient generation techniques. For a small facility ozone is considerably more costly than chlorine; however, for larger treatment facilities and those where dechlorination is required, ozone is often cost-effective. The second disadvantage is that ozone is unknown to both engineers and operators. Likewise, the regulatory agencies are dealing with an unknown item and, thus, often place unnecessary restrictions on the process.

In summary, ozone is a practical, viable alternative to chlorine. In many cases, ozone would be more costly than chlorine. However, how much of a price are we going to put on our streams and rivers? As of this date, it is believed that ozone has no detrimental effects on the environment. In fact, all indications are that ozone is beneficial to the aquatic community since it quickly breaks down to oxygen, thus adding dissolved oxygen to the receiving streams.

We have come a long way the last ten years in this country. Engineers and operators still need to be educated about ozone. However, one thing is very clear—the technology is available, and ozone is here to stay in the United States.

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ULTRAVIOLET LIGHT AS A DISINFECTION ALTERNATIVE

0. Karl Scheible

HydroQual, Inc. Mahwah, New Jersey 07430

INTRODUCTION

A full-scale ultraviolet disinfection demonstration project was conducted at the Northwest Bergen County Sewer Authority treatment plant in Waldwick. Northwest Bergen is a conventional activated sludge plant with eight million gallons per day (mgd) designed capacity and an average yearly flow of approximately five mgd. Results showed that ultraviolet irradiation (UV) is a reliable, cost-effective alternative to the use of chlorine.

Funded jointly by EPA and the Northwest Bergen County Sewer Authority, the experimental program was undertaken in March 1978. The objectives were: to determine the reliability of UV irradiation in achieving desired coliform levels, to assess its maintenance and operational requirements, and to develop process costs relative to other disinfection processes. The field study was concluded in April 1979.

The germicidal effects of UV irradiation occur when its energy is absorbed by the genetic material of the microorganisms, specifically the deoxyribonucleic acid (DNA). This absorption causes death or increased mutation rates in the survivors. All microorganisms contain nucleic acids and are thus susceptible to ultraviolet damage. Ultraviolet energy must penetrate to the nucleic acids, therefore, the relative resistance, or sensitivity of an organism to ultraviolet damage is dependent on the chemical composition and thickness of the cell wall.

The germicidal wavelengths of ultraviolet radiation range from 210 to 310 nanometers (nm) with peak efficiency at, or about, 260 nm. As a consequence, low pressure mercury vapor lamps with their high energy output at 254 nm are very efficient germicidal agents.

The application of UV energy to wastewater is described by the ultraviolet dosage, which is written as D=It, where I=UV intensity (microwatts/cm2) and t=exposure time (seconds). The average intensity to which the wastewater is exposed is a function of the germicidal lamps' rated UV energy output and the transmissibility, or absorbance characteristics, of the wastewater.

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Uniform measurement and reporting of ultraviolet dosage has been lacking in UV investigations to date. Thus it is difficult to compare the results of studies regarding efficiencies and process applications. This is a problem when dealing with the various equipment vendors and when evaluating the results of previous UV investigators.

Work is ongoing to resolve this problem, and HydroQual is directly addressing dosage computations in a new EPA sponsored project at the Port Richmond Water Pollution Control Plant in New York City. Generally, the dosage computation must account for the following:

* Rate of UV energy output of the germicidal lamps.

* Attenuation of the energy as the distance from the source increases.

* Absorption of the energy by the liquid medium.

* Impact of all surrounding lamps on any one point, as defined by the geometry or placement of the lamps.

* Exposure time as defined by the UV system's hydraulic characteristics and the flow rate.

INSTALLATION

The Northwest Bergen plant is equipped with dual, chlorine contact chambers. At the time of the study one remained in- active, which provided an ideal location for the installation of the gravity feed UV disinfection unit.

The system used for this study was a full scale prototype unit manufactured by Pure Water Systems of Fairfield, New Jersey. Figure 1 shows a cutout view of the chlorine contact chamber and the installation of the UV Lamp battery. Two reinforced concrete webs provide overall support. The lamp battery itself is supported by steel bulkheads set into the concrete webs, with an air seal similar to a rubber inner tube along the perimeter between the bulkhead and concrete webs.

The system was placed at the head end of the contact chamber; the flow was controlled by a sluice gate at the influent channel to either of the contact chambers. Flow through the UV system was continuously recorded at the effluent end of the contact chamber, where 4-90ov-notch weirs were installed. A platform was placed over the chamber to provide a work area and support for the ballasts and flow recorder.

The lamp battery consisted of four hundred 85W germicidal lamps with a rated UV output of thirty W at 3527 Angstrom (A),

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Figure 1. Ultraviolet disinfection unit installation.

each jacketed in a quartz enclosure. Power consumption was forty KW at an operating voltage of 480 V. It was possible to vary the dosage application by shutting off the lamp bank in one-sixth increments and by varying the voltage from forty to one hundred percent.

The quartz cleaning mechanism consisted of a support frame with replaceable elastomeric glands over each of the quartz tubes. The wiper was cable-driven at a variable stroke rate by a pneumatic cylinder.

Using the "thin film" concept, the UV unit is designed to minimize absorption of ultraviolet energy by keeping the liquid film relatively thin as it passes through the system. This is achieved by the spacing of the lamps; the nominal liquid film thickness was 0.6 cm, defined as one-half the minimum distance between any two lamps.

EXPERIMENTAL PROGRAM

During the first three months of the experimental program, the system was "de-bugged" and preliminary estimates on the

CONCRETE SUPPORT WALLS

STAINLESS STEEL BULKHEAD

WIPER DRIVE PISTON

INFLUENT

EXISTING Cl2 CONTACT

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performance characteristics of the unit were obtained. As a prototype, the system suffered the expected startup pains. Problems occurred with weather-proofing, wiring, lamp construction, and other mechanical details. Beyond May, the system operated well with low downtime.

Intensive sampling began in June 1978. June through August 1978, the system was monitored over a wide range of dosage levels which were induced by varying the flow, the applied power, and the number of lamp banks in operation.

September through April 1979, the system was evaluated under relatively continuous, steady state operation. Flow through the system was kept in the range of 5 to 6 mgd, with all lamps operating at full power.

The analytical program used total and fecal coliforms (multiple tube procedure) as the indicators of disinfection efficiency. More than 300 sampling sequences, all by grab, were performed using sterile, opaque bottles. Each was analyzed for a number of wastewater quality parameters, including Chemical Oxygen Demand (COD), Suspended Solids (SS) , turbidity, pH, the nitrogen series, and ultraviolet transmissibility at 2357 A. Concurrent monitoring of the unit operation included flow rate, lamps in operation, intensity, and voltage and current (total power application). Continuous logs were kept of operating conditions and maintenance needs. Special studies were also run to evaluate the wiper efficiency and to investigate the impact of photoreactivation.

SUMMARY OF RESULTS

Since the amount of data collected in the study was considerable, only a general overview of the results and the more significant conclusion is presented.

The data indicates that, overall, the secondary effluent was representative of a relatively high quality secondary treatment plant effluent. Coliform levels averaged (geometric) 1.86 X 10^ and 4.8 X 10^ most probable number (MPN)/100 ml for total and fecal coliforms respectively. Suspended solids were low, averaging 6.3 mg/1, as was COD with an average of 27 mg/1. Turbidity averaged 3.4 Formazin Turbidity Units (FTU) and the average absorbance coefficient was 0.38 cm~^. The UV transmissibility of the waters ranged between sixty and eighty percent which is generally high for secondary effluents. An important element of the data is that the variability of the water quality was low--the plant discharge was consistent in quality throughout the study period.

Figure 2 presents a correlation of effluent fecal coliform as a function of applied dosage. The correlation, which is based

Page 110

on the total data file compiled during the study, is a good one with a coefficient, r, of 0. To achieve mean effluent fecal coliform of 200 MPN/100 ml requires a dosage of approximately 60,000 uw-sec/cm2. This requirement equals approximately a 5 KW/mgd lamp requirement for wastewaters of similar characteristics .

o o V. Z a Z

> t <n z Ul a 3 tr o u. 3 o o -I < o UJ ll_

300,000

200,000

100,000 50,000

20,000 IQ000

5,000

2,000 1,000

500

200 100

50

20 10

5

FECAL COLIFORM EFF FC =(1.25 *IOls)D-J-iT

r«0.66

10

~ .~ • • I • •• • •

• * ^ • "C. -V . . • • • •• **

• • • • A • la m • mm •• • •K • r-- -N .

" • v

20 40 60 80 100 200 400 600 BOO

ULTRAVIOLET DOSAGE (lo'/jW-see/cm^

Figure 2. Second order dose-response relationship for fecal coliform.

From October 1978 through January 1979, conditions were held constant and the system was monitored for uniformity of operation. At an average flow of 5.2 mgd and an exposure time of 2.2 seconds, the mean fecal coliform density was 28 MPN/100 ml with a range of 2 to 240 MPN/100 ml. This result illustrates well the unit's ability to meet long term effluent requirements for fecal coliform.

Page 111

Operation and maintenance requirements are low because of the simplicity of the overall system. Maintenance, other than parts replacement, is minimal, requiring only normal monitoring and upkeep. Recommended lamp life is ten months. The wiper mechanism was highly efficient and trouble-free over approximately 7,500 hours of operation. Wiper gland replacement is recommended once a year simply as a preventative maintenance procedure.

Actual system installation at a new facility will require proper housing and should be designed to allow lamp replacement without shutdown. Power application will be keyed to flow rate and, potentially, to water quality. Prescreening will be recommended when significant fibrous material, such as algal clumps, are present in the discharge. These materials tend to catch on the quartz and are swept to the ends of the unit by the wiper where they accumulate and eventually must be cleaned out. Prescreening would eliminate this maintenance problem.

Cost estimates for the UV system indicate that it is competitive with chlorine. Between two and six cents/1000 gallons is projected for ultraviolet disinfection, four to eight cents/1000 gallons for chlorination and ten to fourteen cents/1000 gallons for ozonation.

Investigations of photoreactivation were conducted concurrently with the field program. Photoreactivation is a phenomenon unique to ultraviolet irradiation whereby exposed bacteria have the ability to repair UV inflicted damage when subsequently exposed to light energy in the range of 310-500 nm. Thus, the coliform density will increase downstream of the UV system due to a fraction of the damaged cells undergoing repair.

These studies indicate that the degree of repair is dependent on seasonal conditions, with minimal repair occurring in the winter and maximum in the summer. Reactivation has been shown by the Northwest_Bergen studies to account for a five to ten factor increase in effluent fecal coliform density one hour after ultraviolet_irradiation. Thus, if the effluent density is 10 MPN/100 ml immediately after exposure, it increased to 50 to 100 MPN/100 ml after one hour exposure to natural sun- light.

Effluent guidelines are written for the point of discharge. Thus repair, and aftergrowth are not typically accounted for in regulatory codes. However, the impact of photoreactivation can be addressedin the design of a system by imposing higher dosages. Ultraviolet disinfection, even under these conditions, would remain cost-effective.

In conclusion, UV is feasible and applicable to secondary

Page 112

effluents. It is cn^r «-• and main ten ance requirements on^lant Sf-êSS 0Peration

hlorxHaticm and ozonation systems n comParable easily installed in existing plants ' it: can be

SPaCe ln new than chlorination systems0nSiêrab1^

of more variable"?fluentûalitv"5 rh direcl:ed to: evaluations dosage expressions and design bales andS^bl^Shment of uniform

reactivation. Hopefully, with inter^Q? • m7Xinpact of Photo- lation m plants over the next fel Zt ln UV ar}d its instal- gained to advance the technolncrv ^ ^rs experience will be operational and maintenance nefds in ? firin!y establish proven alternative disinfection nrn^J10^ liSht is a

further attention. procedure and fully deserves

Page 113

BROMOCHLORINATION

Norman E. LeBlanc

Chief, Technical Services Division Hampton Roads Sanitation District

INTRODUCTION

Bromine Chloride (BrCl) is the most usable form of bromination for most applications. BrCl is a mixture of bromine and chlorine which exists in equilibrium in both the liquid and gaseous phases. The advantages of BrCl over Br are:

1. It is less corrosive

2. It has increased solubility in water (2.5 times that of Br and 11 times that of CI2)•

3. BrCl vaporizes readily at room temperature and pressure as opposed to Br which remains in the liquid phase.

RESIDUAL STABILITY

As with CI2, BrCl reacts rapidly with the ammonia nitrogen in the effluent to form bromamines. Bromamines are stronger oxidants than chloramines and subsequently less stable. Studies have shown that the germicidal efficiency of the bromamines is comparable to that of hypochlorous acid under wastewater conditions, (White, 1978). This property of the bromamines makes them comparable if not superior to CI2 as a bactericide and viricide in wastewater.

The instability of the residual is another advantage of BrCl over CI2. The chloramines produce a stable residual over the 30 minute detention time (Figure 1). With BrCl, residual decay (Figure 2) is rapid and 90% complete within 30 minutes. While BrCl and CI2 have similar LC50 toxicity levels (0.25 mg/1 for juvenile spot), the rapid decay eliminates the residual prior to discharge (LeBlanc et al, 1978). Therefore, in areas where CI2 toxicity is a problem, BrCl can eliminate the need to dechlorinate.

DISADVANTAGES

The instability of the residual has some drawbacks, mainly because it is related to the increased reactivity of the bromamines. Therefore, as effluent quality deteriorates, the

Page 114

amount of BrCl required to disinfect increases. In addition to an increase in initial demand, the level of residual may also need to be increased in order to affect good bacterial inactivation.

In order to demonstrate this point, bench scale studies were performed on effluents from two secondary treatment plants owned and operated by the HRSD. The studies observed the relative merits of BrCl and CI2 as disinfectants. Character- istics of the two effluents are presented in Table 1. As you can see, there is a marked contrast in quality between the two effluents. The dose-residual curve for CI2 (Figure 3) shows the response to the poorer quality effluent at Chesapeake- Elizabeth (50-60% more CI2 demand). In contrast, the dose- residual curve for BrCl (Figure 4) shows a greater response of BrCl to changes in demand (400% more BrCl demand).

Suspended BOD Solids TKN-N NHo-N TOC

p:1-ant (mg/l) (mg/1) (mg/1) (mg/1) (mg/l)

James River TP^" 7 4 3.8 2.4

Chesapeake-Elizabeth 20 13 31.8 20.0 50 Tp2

1. 20 MGD conventional waste activated sludge plant, Newport News, VA

2. 30 MGD contact-stabilization plant, Virginia Beach, VA

TABLE 1: Effluent characteristics from the James River and Chesapeake-Elizabeth Treatment Plants

Disinfection efficiency of BrCl is also more sensitive to changes in effluent quality than CI2. Table 2 presents the Cl^ results for the jar tests. Note that a CI2 dosage of 0.8 mg/1

CHESAPEAKE-ELIZABETH TREATMENT PLANT

5 min. 15 min. 30 min. Residual Dosage Residual Residual Fecal Coliform

(mg/1) (mg/1) (mg/1) (#/100 ml) (mg/1) Fecal Coliform (#/100 ml)

0.8

2.5

4.1

5.8

8.3

0.10

0.17

0.85

1.95

4.40

<0.05

0.10

0.65

1.70

4.05

>8000

2346

20

<20

<20

<0.05

0.10

0.52

1.55

3.65

>8000

310

20

<20

<20

Page 115

JAMES RIVER TREATMENT PLANT

5 Min. 15 Min. 30 Min. Dosage Residual Residual Fecal Coliform Residual Fecal Coliform (mg/1) (mg/l) (mg/l) (#/100 ml) (mg/1) (#/100 ml)

0.8 0.30 0.25 487 0.25 92

2.5 1.55 1.35 <20 1.35 <20

4.1 2.85 2.60 <20 2.50 <20

5.8 4.20 4.10 <20 N.A. <20

8.3 6.70 6.50 <20 6.20 <20

TABLE 2: Chlorine residuals and fecal coliform densities after 5, 15 and 30 minutes contact time in final effluents from the Chesapeake-Elizabeth and James River Treatment Plants.

is needed to produce a bacterial level of <20 Fecal Coliforms per 100 ml in James River effluent. However, a 4.1 mg/l CI2 dose was required to obtain a similar bacterial level in Chesa- peake-Elizabeth effluent. The increased dosage in the Chesapeake- Elizabeth effluent was required to satisfy the initial demand. Extrapolation of the data indicates that both effluents would produce similar bacterial levels at the same CI2 residual concentrations.

Table.3 presents the BrCl results for the jar tests. How- ever, here we are aiming for a 5 minute residual for dosage control (as opposed to 30 minutes for C^). Past studies have shown


5 Min. 15 Min. 30 Min. Dosage Residual Residual Fecal Coliform Residual Fecal Coliform (mg/l) (mg/l) (mg/l) (#/100 ml) (mg/l) (#/100 ml)

1.2 <0.08 <0.08 >8000 <_0.08 _>8000

3.7 10-08 £0.08 3260 £0.08 3009

6.1 0.24 0.12 539 £0.08 361

8.5 0.57 0.24 120 0.20 35

12.1 1.47 0.57 228 0.41 20

Pane 116

5 Min JAMES RIVER TREATMENT PLANT

i5 Min.

20

<20

<20

<20

<20

0.08

0.82

2.28

3.34

4.40

<20

<20

<20

<20

<20

1

Dosage Residual Residual 30 Min.

y ^

3.7

6.1

8.5

12.1

TABLE 3:

0.24

1.79

3.34

5.30

7.25

0.16

1.17

2.69

4.16

5.54

Bromine Chloride residnfllc: -p i ^ after 5 15 onH • fecal colxform densities

effluents from the Chpâ times in final Treatment Plants. Peake-Elizabeth and James River

a 1.0 rag/1 residual, a 3 0 m"/? dos P " In 0rder to "■"ntain effluent as opposed to 10 0 mi/1 T rt 13 re

1c5uired in James River

Effluent quality influences th*pf? C^saPeake-Eli2abeth effluent, residual as can be seen frSn, ^ 5 !Ct^Veness'of the BrC1

0.35 mg/1 provides effluent feral f-£n Ta^le 5- A residual of 100 ml at James River; in contrast}eVeiS 0f -20 Per

required in Chesapeake-Elizabeth 0f 1*5 m&/1 is

of similar bacterial quality. fluent to produce effluent

full Icalfprojec^s acJoss^^fco^t^y^lff^ '0ut ^ tently be of higher miplit-Tr Effluent must consis- treatment plant in order for B^Cl^to111"? by laW for a secondary Any loss of effluent quIlUy could 1^ ,°™ ?ost-effectively. capability and require the swi?ph v ^ of ?SS in disinfection practiced) . Most BrCl svstemf £2' ^ ^ Cl2 (as has been

case of problems; the switch is pIc back-up chlorination in similar. easy because feed systems are

TRIHALOMETHANE PRODUCTION

trihalomethanesîs of con^fm311^ bJief^^d partiûlarly the potential for the formation of THH'J K Z 0n the relative part of a pilot study (Roberts ?! . was done as the results. The results show Br-n t- u Table 4 presents

Cl2,that is .to form grater amonn^ 50Jb?uin?re reactive than

also shows that when ammonia SitrLen ^lh?loiPethanes. The data decrease to a point where a fr-PP £ ? levels xn an effluent trihalomethane production increases ^ residual can exist,

Page 117

Effluent I: NH3-N=14.2 mg/l

Sample CHCl^

Unhalogenated 3.8

Chlorinated 8.0

Bromochlorinated 3.1

Trihalomethanes (ug/1)

CHCl0Br

0.3

CHClBr^

0.3

0.3

CHBr-

12.1

Effluent II: NH2-N= 0.1 mg/l

Sample CHCI2

Unhalogenated 8.0

Chlorinated 23.1

Jet Chlorinated 18.4

Trihalomethanes

CHCloBr

4.1

1.7

CHClBr, I

0.8

3.3

TABLE 4: Trihalomethane levels (ug/1) in secondary effluents with various concentrations of ammonia nitrogen which have been disinfected by various halogens and techniques

The amounts of trihalomethane produced in the halogenated process were extremely small. In the chlorination process, only 0.09% (by weight) of the chlorine applied is accounted for as chloroform in the effluent as opposed to 0.377o for bromine chloride.

SUMMARY

Advantages

1. BrCl is a good wastewater disinfectant.

2. Residual stability precludes the potential problems associated with the stable chlorine residual.

3. Feed systems are essentially identical to that for CL2, therefore, additional operator training is not required.

Page 118

Disadvantages

1. BrCl efficiency is related to effluent quality.

a. Effluent quality which is within 30/30 permit levels may still not be suitable for BrCl.

b. Fluctuations in effluent quality will make the use of BrCl difficult if not impossible because of the inability to maintain suitable residual levels.

2. An alternate chlorination system may be necessary in order to maintain disinfection during periods of poorer effluent quality.

3. The increased TKM production resulting from BrCl may or may not be a problem. Further, work is needed on assessing the impact of low levels of THM's on the estuarine environment.

ILLUSTRATIONS Page 119


PLANT

5 10 15 20

CONTACT TIME (MINUTES)

Figure 1 Chlorine residual decay in effluents

CONTACT TIME (Mln)

Fl9Ure 2 aBnTN^NCh0O6n™g/rS,'dUal decay f0r SUSPended S0'1ds 6° "9/'

Page 121

BrCI DOSAGE (mg/l)

Figure 4 Dosage of Bromine Chloride and 5 minute residual concentrations at

Lnesapeake - Elizabeth and James River treatment plants.

Page 122

REFERENCES

1. White, C.G. 1978. Disinfection of Wastewater and Water for Reuse, Van Nostrant Reinhold Environ. Eng. Series, p. 297- 299.

2. LeBlanc, N.E., Roberts, M.H., Wheeler, D.R. 1978, "Disin- fection Efficiency and Relative Toxicity of Chlorine and Bromine Chloride - A Pilot Plant Study in anEstuarine Environment", Special Report in Applied Marine Sci. No. 206, Va. Inst. Mar. Sci. 65 p.

3. Roberts, M.H., LeBlanc, N.E., Wheeler, D.R., Lee, N.E., Thompson, J.E., Jolley, R.L. 1980. "Productionôf Halo- genated Organics During Wastewater Disinfection", Special Report in Applied Marine Sci. No. 239, Va. Inst. Mar. Sci. 48 p.

Page 123

DISINFECTION IN WASTEWATER TREATMENT UNDER THE EPA's INNOVATIVE ALTERNATIVE PROGRAM

James F. Wheeler, PE

U.S. Environmental Protection Agency Municipal Technology Branch (WH-547)

Washington, D.C. 20460

BACKGROUND

Water is among the most essential and highly treasured of all our resources. It is treasured for its great beauty as well as for its host of uses. Unfortunately, many of the uses tend to pollute water. However, man-made problems may have man-made solutions. To this end, the Federal Water Pollution Control Act Amendments (Public Law 92-500) were passed by Congress in 1972 to begin the organized clean up of our nation's waters.

One of the most important provisions of the 1972 Act deals with the problem of municipal sewage treatment plant effluents. The Construction Grants Program was developed to help eliminate this problem. It provides federal funding for up to 75 percent of the total cost of designing and constructing municipal wastewater treatment facilities which help attain the water quality goals set by the Act. These goals include making the nation's water "fishable and swimable" by 1983, and eliminating all discharge of pollutants to water bodies by 1985. To date, billions of dollars have been spent by the federal government to help local communities construct or update wastewater treatment plants, however, much work remains to be done.

Congress amended the Water Pollution Control Act again in 1977^(PL 95-217) to redefine the. task remaining and to encourage continuing efforts to attain the 1972 goals. While this mid- course correction, commonly called the Clean Water Act of 1977, does not represent a^complete reorientation from the 1972 Act,' it does contain significant changes in emphasis in certain programs.

One change is in the Construction Grants Program. Alter- native technologies for wastewater treatment may be more economical than conventional methods, yet, there is a tendency to cling to conventional systems without adequate consideration of the available alternatives. Thus the design of new plants often complies with the letter of the law but not really with its intent. For example, discharges of wastewater effluents sometimes contain valuable nutrients, such as nitrogen and

Page 124

phosphorus, which cause pollution problems down stream. Ever increasing accumulations of sewage sludge also create new disposal problems that require special attention and management. ^ Finally, and probably the worst of all, communities sometimes build expensive wastewater treatment systems when simpler and more economical solutions are available.

Recognizing that incentives were needed to overcome such problems, Congress restructured the Construction Grants Program in 1977 to encourage the use of innovative and alternative technologies in wastewater treatment. The Law provides an increase in the federal share from 75 percent of the cost for conventional systems to 85 percent for the design and construction of innovative and alternative treatment facilities. The law also states that projects or portions of projects already underway with 75 percent funding are eligible for the additional ten percent in federal funding if they qualify as innovative or alternative. The Law also provides for grants of up to 100 percent for technical evaluation and for dissemination of information pertaining to the treatment works in innovative and alternative systems.

To further reduce municipalities' risk in building innovative and alternative facilities, Congress instructed the U.S. Environmental Protection Agency (EPA) to provide up to 100 percent of the cost to modify or replace such a system that fails within two years when operated properly. The Act also requires that certain percentages of federal allocation be set aside in each state to be used only for funding innovative and alternative projects. A grant application may also receive priority funding if the technology to be used can be classed as innovative or alternative.

INNOVATIVE/ALTERNATIVE (I/A) PROGRAM

In general, innovative and alternative technologies use systems which reclaim and reuse water, recycle wastewater constituents, eliminate the discharge of wastewater constituents, or recover energy from the wastes. Innovative technologies for wastewater treatment show promise for success and cost- effectiveness, but have not been fully proven under the circumstances of their intended use.

The responsible state official or EPA Regional Administrator determines whether proposals are innovative, but some guidelines are helpful in the preliminary stages of the planning process. For conventional treatment systems to be considered innovative, the projected life-cycle cost of the treatment works must be at least fifteen percent less than the most cost-effective system that does not use the innovative technology, or the net primary energy required to operate and maintain the treat-

Page 125

ment works must be at least twenty percent less than the net energy required to operate the most cost-effective conventional system. In addition, a system may be declared innovative by the EPA Regional Administrator because it provides significant public benefits through the advancement of technology in a specific region.

Traditional engineering practice has always dictated a very low element of risk for the construction of full scale public works projects supported by federal expenditures. In passing the Clean Water Act, Congress clearly intended that a higher degree of risk be permitted for the set-aside funds for innovative technology. The permitted degree of risk must be compared to the potential for significant state-of-the-art advancement. High risk, high potential projects may be judged acceptable, where high risk, low potential projects may be deemed unacceptable.

For alternative technology to be considered innovative, it must meet one of the criteria above or fulfill any one of four additional criteria.

* Improve operational reliability and thus decrease the susceptibility of the system to upsets or interference.

* Improve environmental benefits such as water conservation and reuse, more effective use of land, and improved ground- water quality.

* Improve the joint industrial and municipal treatment potential where both discharge into the municipal system.

* Improve the management of toxic materials that occur in the wastewater.

Many conventional as well as alternative processes are described in the EPA's Innovative and Alternative Technology Assessment Manual (MCD-53) . Copies of the manual! are available from EPA Regional Offices or headquarters.

CURRENT STATUS

The following chart lists the number of projects funded under the I/A program.

Page 126

Total Funds Available

7% of $99 millior

34% of $68 "

85% of $84 "

Of the 758* projects, 152 included innovative technology ($24,406,278) and 650 included alternative technology ($76,901,389) 162 were design projects ($4,463,888) and 596 were construction and design/construction projects ($96,843,799).

Eleven states, six territories and the District of Columbia have not yet funded any innovative technology projects. One state, five territories, and the District of Columbia have not yet funded any alternative projects. Twenty-two states have obligated all of their FY 79 set-aside funds and Rhode Island and Indiana have obligated all of their FY 80 I/A set-aside funds.

Table 1 lists innovative technologies which have been funded. The eighteen overland flow, fifteen UV disinfection and seven solar technology projects together comprise 29 percent of all of the innovative technologies funded.

Fiscal Year # I/A Projects Funding Funded

81 (1st, 2nd, 60 $6,478,200 3rd Qtrs.)

80 195 $23,252,318

79 503 $71,577,149

Total 758 $101,307,667

Number Innovative Description of Technology Technology Projects Funded *

1. Overland Flow 18 2. UV Disinfection 15 3. Active/Passive Solar Heat Pump

Energy Recovery and Other Energy Recovery Applications 7

4. Intermittent Sand Filtration 6 5. Oxidation Ditch 6 6. Draft Tube Aeration in an Oxidation

Ditch 6 7. Use of an Intrachannel or Integrally

Built Clarifier in an Oxidation Ditch 5 8. Hydrograph Controlled Discharge Lagoons 4 9. Biological Phosphorus Removal

(Phostrip/Bardenpho) 4 10. Silviculture 4

* Since some alternative projects are also considered as innovative, the total number of projects is less than the sum of the subcategories.

Page 127

. _ m , Nxmiber Innovative Description of Technology Technology Projects

r-r. 7- , Funded * 11. Microscreen (1 micron mesh)— 3 12. Odor Control 3 13. Septic Tank Effluent Collection

and Transport 3 14. Sewage/Sludge Lagoons 4 15. Aquaculture 4 16. Co-incineration 3 17. Wetlands 2 18. Tubular Screw Pumps 2 19. Use of Powdered Activated Carbon/

Regeneration 2 20. Static Pile Sludge Composting 3 21. Ozonation 3 22. CSO Screening/Treatment 3 23. Fluidized Bed System 1 24. Upflow Packed Bed Reactor 1 25. Waste Pickle Liquor Storage/

Injection 1 26. Recirculation Rock Filter 1 27. Inclined Plate Settlers 1 28. Tube Settlers ^ 29. Combined Anaerobic Digestion 1 30. Submerged Draft Tube Turbine

Aerator ]_ 31. Dome Diffused Aeration 1 32. Subsurface Gravel Bed Effluent

Polishing/Disposal to Surface Water 1 33. Mechanical Sludge Composting 2 34. Single-state Nutrification with

Pure O2-Covered Basins 1 35. Vacuum Dried Sludge Beds 1 36. Starved Air Combustion of Sludge 1 37. Floating Hydraulic Dredge on a

Sand Filter 38. Air Drive RBC's 1 39. Series Use of Vacuum/Belt Sludge

Filters 1 40. Hydraulically Assisted RBC's 1 41. Shallow Well Injection of Effluent 1 42. Spray Irrigation/Deep Well Injection

of Effluent ]_ 43. Dual Aerobic/Anaerobic Sludge

Digestion 2 44. Sludge Application of Land Using

Traveling Gun ]_ 45. Use of Digester Gas for Power l 46. Use of Waste Stream ]_ 47. Belt Filter Press 1 48. Modified Activated Sludge 1

Page 128

Number Innovative Description of Technology Technology Projects

Funded * 49"! Deep Lagoon, U-Tube Aerator,

Decantor Clarifier 1 50. Computerized Financial Management

System 1 51. Sludge Dewatering-Solvent Extraction 1 52. Flocculating Clarifiers 1 53. Sequencing Batch Reactor 1 54. Ash Detoxification-Fluid Bed

Chromium Reduction 1

* All projects in design or under construction

TABLE 1: Innovative Technologies funded thru the Second Quarter FY 81

In EPA Region III (Philadelphia) a total of fifteen innovative projects and 29 alternative projects have been funded at an estimated cost of over five million dollars. Table 2 summarizes I/A projects in Region III by states. Table 3 is a list and brief description of fourteen innovative projects located in the Region.

DISINFECTION ALTERNATIVES

Of the projects funded in Region III, only the Smithsburg, Maryland project includes an innovative disinfection system. The Smithsburg plant is designed to treat 200,000 gallons of secondary effluent with ultra-violet (UV) disinfection and to produce an effluent with a bacteria count of less than 200 most probable number (MPN) per 100 milliliters (ml). The disinfected effluent is then discharged to the surface waters near the plant.

To date nearly all disinfection systems installed under the I/A program have been ultra-violet processes. Fourteen UV systems and two modified ozone systems are currently operating or are under construction. Although ozone is an alternative to chlorination, it is generally considered as a convenient treatment and, thus, does not qualify for additional funding as an innovative or alternative process under the I/A program.

Other alternative disinfection systems which have been demonstrated in the field, but not funded for full scale operation include iodination, bromination, chlorine dioxide,

Page 129

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Project Name I/A Component"

Somerset County Sanitary District, Fairmont, MD

Back River (Baltimore), MD

Jonesville, Jerusalem, Montgomery County, MD

Queen Annes County (Kent Narrows), MD

Smithsburg STP, MD

St. Clement's Shores St. Mary's Metropolitan Commission, MD

Boones Mill STP, VA

Elkton, VA

Valley STP, WV

Mount Holly Springs STP, PA

New Hanover STP, PA

S. Central York, STP, PA

Craigsville, VA

Kenbridge, VA

TABLE III: Innovative Projects

Vacuum collection system

Waste pickle liquor storage and injection

Pressure sewers, batch process activated sludge and land treatment

Vacuum collection system

UV disinfection (saves 15% life cycle costs)

Grinder pumps and pressure sewers, spray irrigation

On-site systems, pretreatment for aquifer recharge for central facility

Sludge application

Grinder pumps and pressure sewers

Carousel process saves 15% life cycle costs and 20% net primary energy

Land treatment system

Spray Irrigation

Overland flow treatment

Land Treatment System

Funded in Region III

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sodium hypo-chloride, UV/ozone combination, and other chlorine compounds. Many of these have been utilized in individual on-site treatment systems under the EPA small flows program.

^ EPA's Office of Research and Development (ORD) is continuing its investigation of several other possible alternatives. These include ionizing radiation (cobalt 60 or cesium 137); thermal disinfection (70-750C for 20-60 minutes); high pH (11.5-12 for 30 min at 1 C); low pH (1-2 for 60 minutes or longer); lagoon storage followed by land application; and other halogenated compounds. Of these, only the lagoon storage followed by land application appears to have any real promise as a low cost disinfection alternative. Data on operating lagoon systems indicate that two stage lagoons (two cells) with a design storage of twenty to seventy days per cell can consistently achieve effluent bacteria levels of less than 1000 MPN/100 ml. The effluent from these systems, without any disinfection, is suitable for land application to agriculture or forest where limited human contact is involved. In addition, lagoons, with more than two stages (three or four cells), with the same design storage time per cell, can consistently achieve effluent bacteria levels of less than 200 MPN/100 ml. This effluent, without any disinfection, is suitable for application in public use areas such as parks or golf courses.

EPA believes that using lagoon effluent for agricultural or recreational purposes provides a valuable alternative to disinfection by reducing costs, removing the need for dechlorination facilities and eliminating many of the problems associated with halogenated organic or hydrocarbons. In addition, such projects are eligible for increased funding under the I/A program.

FUTURE OUTLOOK

Like most other Federally funded programs, I/A is currently under review by the Reagan Administration and the Congress. The Administration has requested a one billion dollars recision in 1980 and 1981 construction grants funding. It has also asked Congress to eliminate all construction grants funds for 1982 unless certain changes are made in the Clean Water Act. If the changes are made, the Administration will recommend restoration of $2.4 billion dollars for the 1982 fiscal year and funding at the reduced level of $2.4 billion dollars for fiscal years 1983 thru 1985.

Congress is currently considering the requested recision and has indicated that the recommended changes will be made. Both the House and Senate have prepared drafts of the changes proposed by the Administration, which, if implemented would

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include:

* Extend the I/A program for one year to September 30, 1982.

* Provide I/A funding at the discretion of the State Governor, not to exceed three percent of the State's construction grant allocation.

* Limit funding to projects that would significantly improve water quality.

* Eliminate funding for future capacity in treatment facilities expansions.

* Eliminate funding for interceptor sewers.

Although some modifications to the I/A program are being considered and reductions in construction grants funding are anticipated, the I/A program appears to be sound and major provisions in the law will remain unchanged. For instance, the law would still require every applicant for a construction grant to fully study and compare innovative and alternative wastewater treatment technologies with conventional methods before selecting a system.

SUMMARY

In summary, innovative and alternative wastewater treat- msnt technologies should reduce cost, save energy, increase reliability, manage toxic materials, provide environmental benefits, improve management of joint municipal-industrial systems or clearly serve the public interest. To encourage the use of innovative and alternative wastewater treatment technologies where practical, the Clean Water Act of 1977 requires that innovative and alternative technologies be studied and evaluated for each proposed wastewater treatment project before an engineering or construction grant is made. In- novative and alternative systems frequently have lower overall costs than conventional systems; and since they qualify for 85 percent federal funding, they can significantly reduce local costs. Finally, if an innovative or alternative system fails within two years, the Federal Government can fund the total amount necessary to modify or replace the system.

Clearly, every^municipality involved in planning wastewater treatment facilities is challenged to be innovative and to consider all possible alternatives before deciding the best technology for its particular situation.

We must all work together to improve and maintain the natural environment of the United States for present and future generations.

Page 133

ECONOMIC ASPECTS OF ALTERNATIVE MODES OF DISINFECTION

Mark E. Alpert John D. Bonomo

Metcalf & Eddy, Inc. Silver Spring, Maryland 20904

Chlorination is the most commonly used method of disinfecting municipal wastewater in the Chesapeake Bay region. Scientific investigators and regulators have raised concerns regarding the environmental hazards associated with chlorine residual present in wastewater effluent discharged to surface waters. In fact, legislation and regulation have in some cases actually banned the discharge of chlorinated effluents to some environmentally-sensitive receiving waters (Maryland General Assembly, 1981).

Numerous alternative disinfection techniques are being considered for municipal wastewater treatment. These alternatives include Hypochlorite, Ozone, Ultraviolet radiation (UV), Bromine Chloride, and using chlorine associated with dechlorination.

Other than environmental effects, economics is perhaps the most important factor considered in making an objective, comparative evaluation of these alternatives. Since factors contribute to the economic comparison of different disinfection techniques, a thorough investigation and evaluation are necessary for each treatment facility requiring disinfection (Smith, 1978; Clark, 1981; Metcalf & Eddy and TKDA, 1979). The results of such an economic evaluation vary according to local conditions, such as the flow to be treated, the location of chemical suppliers and sources of electrical power, the availability of qualified staff, and site restrictions. This paper discusses the disinfection alternatives and will focus on some of the economic considerations typically evaluated during the disinfection selection process.

CHLORINE, a reliable and effective bacterial disinfectant, is used primarily in the form of liquified chlorine gas. Special handling and storage facilities are associated with its use, because of its hazardous nature. Chlorine maintains its strength indefinitely and therefore does not lose value over time. Gaseous chlorine contacts wastewater through ejectors; application rate is usually paced by flow and timed by measuring chlorine residual. Since a minimum of thirty minutes contact time is required for chlorination facilities, it is necessary to construct associated chlorine contact basins.

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Chlorine gas is available from chemical suppliers in a variety of containers ranging from 150 pound cylinders to 55 ton railcars. One ton cylinders are typically used in wastewater disinfection applications. The unit cost of chlorine which varies markedly with the size of delivery, affects the overall cost of treatment. Recent price information from the Hampton Roads Sanitation District indicates that chlorine delivered in one ton cylinders ranges in price from $110 to $325 per ton depending on the location of the facility and the container form. Table 1 presents additional information about the unit costs of chlorine and other disinfection alternatives.

Gaseous Chlorine

$110 - 165/T for Rail Car $275 - 325/T for Ton Cylinder $0.14/lb

Sodium Hypochlorite

$650/T (15% Available Chlorine) $0.33/lb

Ozone

Generated from Air Stream

$1000 - 1300/T $0.50 - 0.65/lb.

Generated from Oxygen

$700 - 1200/T $0.35 - 0.60/lb

Bromine Chloride Ultraviolet Irradiation

$0.25/lb. Physical Process

$0.05/1000 gal. Treate<

Table 1: Unit Costs of Disinfection Alternatives

Recent legislation and regulations in Maryland prohibit the discharge of chlorinated effluents to trout streams and other water bodies containing aquatic life which is adversely affected by chlorine; these regulations effectively require dechlorination of the chlorinated effluent. The addition of dechlorination facilities may increase the overall cost of disinfection with chlorine by approximately twenty five percent.

HYPOCHLORITE, either sodium hypochlorite or liquid bleach, or calcium hypochlorite (HTH powder) can be used as an alternative to liquid gaseous chlorine. Although easy and safe to handle, hypochlorites can be stored in corrosion resistant containers only. Shelf-life or storage time for these forms of chlorine

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are limited and, thus, they require more frequent delivery.

Hypochlorite can be purchased as a liquid from chemical suppliers or can be generated on-site by electrolyzing a brine solution. On-site generation is an energy intensive process consuming three times the energy of a gas chlorination system of equal capacity as shown in Table 2. Although energy costs for on-site generation are higher, the purchase of chemicals is minimized or eliminated. Moreover, on-site generation can prove to be economically advantageous in a medium-size facility (ten million gallons per day) located near a ready source of brine such as seawater. This alternative should be carefully evaluated if such local conditions exist.

Manpower requirements associated with batch processes for calcium hypochlorite are considerably higher than for sodium hypochlorite or gaseous chlorination.

Gaseous Chlorine

Sodium Hypochlorite

Ozone/Oxygen

Bromine Chloride

Ultraviolet Irradiation

1.3 Kilowatt hours per pound (kwh/lb)

4.2 kwh/lb

6.0 kwh/lb

1.3 kwh/lb

350 kilowatt hours per million gallons

Table 2: Energy Consumption of Alternative Disinfection Processes

Until recently, OZONE was considered the only viable alternative to the chlorination of drinking water or wastewater effluents. Although the water quality and environmental effects are primarily unknown, preliminary indications from numerous scientific evaluations indicate that the environmental impacts of ozone will probably be significantly less than chlorine.

Ozone is the most powerful disinfectant available. It is highly unstable and must be generated on-site at the treatment facility by subjecting air or high purity oxygen to high electric voltages (LePage, 1981). Ozonation is associated with high energy consumption, between four and eight times more intensive than gaseous chlorination (Storer and Jamis, 1979). Although use of ozone is considered safe for operating personnel, regulatory agencies have diminished contact titne requirements to fifteen

Paqe 136

minutes because of its high reactivity (Derrick, 1979). Lower contact time requirements result in lower costs associated with structures when compared to gaseous chlorination.

Energy consumption and the need for on-site generation generally make ozone the most expensive alternative to chlorination available.

ULTRAVIOLET IRRADIATION (UV) has a very high disinfection efficiency, and its energy consumption is reasonable. However, because UV is a physical process requiring no chemical addition, it is difficult to accurately compare the cost of this alternative on a material basis. Although relatively untested as a wastewater disinfectant, UV appears to have great potential; its reliability and effectiveness have been demonstrated through long term use in the food processing industry. Recent advancements in the design of UV lamps have reduced its associated energy consumption to approximately 350 kilowatt hours per million gallons of flow.

The effectiveness of UV varies with the depth of the film and the turbidity of wastewater to be treated. High turbidity effluents are difficult to irradiate because the contained solids absorb a significant amount of energy. Therefore, UV disinfection is most practical when a high quality effluent is produced by the facility. Finally, using UV eliminates the contact tank and, thus, significantly reduces total cost. In fact, numerous studies have demonstrated that UV is equivalent to or less expensive than chlorination (Scheible, Binlowski and Mulligan, 1978). The greatest question associated with its use as a wastewater disinfection method, however, is the lack of available user information about related operations and maintenance costs.

BROMINE CHLORIDE is an equilibrium mixture of bromine and chlorine which exists as a liquid because of its low vapor pressure (Greene, 1979). Although it requires similar feed systems and a contact tank, bromine chloride possesses a number of distinct, physical advantages over chlorine and promises to be cost competitive with chlorination (Keswick, Fujioka, Burbank, & Loh, 1977; Mills, 1979). Moreover, chlorobromination has been demonstrated to have considerably lower environmental effects on aquatic life than chlorine. Energy consumption figures for bromine chloride are similar to those for chlorine, and therefore quite less than those for ozone or hypochlorite generation.

This discussion demonstrates that reliable and cost- effective alternatives to chlorination disinfection exist. Com- puting the economics of disinfection is a dynamic exercise based

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on local conditions and influenced by many factors. Consideration of local consumption figures and other operations and maintenance costs require careful evaluation prior to recommending any process.

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REFERENCES

Clark»^Robert M. , Evaluating Costs and Benefits of Alternative Disinfectants. Journal of the American Water Works Asso- ciation, February 1981.

Derrick, David G. and Perrick, Jerry R., Guide to Oxone Eauin- ment Selection. Pollution Engineering^ November 1979.

Greene, David G., Wastewater Disinfection with Bromine Chloride Presented at the Annual Meeting of the Chesapeake Water Pollution Control Association. June fS 1q7Q

House Bill 570. 1981 Maryland General Assembly Session. An Act Concerning Water Resources and the Prohibition of Dis- charge ot Chlorinated WaterT

Keswick Bruce H., Fujioka, Roger S.; Burbank, Nathan C. Jr; Loh, Philip C., Bromine Chloride: An Alternative Disin- fectant—to Chloride. U. of Hawaii Technical Memorandum Report No. 54. June 1977.

LePage Wilfred L., The Anatomy of an Ozone Plant. Journal of the American Water Works Association. February 1981.

Metcalf & Eddy and TKDA. Alternatives to Disinfection Facilities at the Metropolitan Wastewater Treatment Plant. MWCC Project No. 76-28. August 1979. —

Mills, J.FBromine Chloride Disinfection -- State of the Art. Presented at the 1979 Annual Conference of the Water Pollution Control Federation.

Scheible 0. Karl; Binlowski, Gloria; Mulligan, Thomas' J. , Full Scale Evaluation of Ultraviolet Disinfection of a Secondary Effluent. Proceedings of the National Symposiutn on Wastewater Disinfection Technology. September 18-20,

Smith, James E., Wastewater Disinfectants: Many Called - Few Chosen. Waster & Wastes Engineering. June 1978.

Storer, Enos L. and Jamis, Robert N. , Engineering and Economic Aspects of Wastewater Disinfection with Ozone Under Stringent Bacterial Standards. Presented at the Inter- national Ozone Association. 4th World Congress. November

Page 139

WASTEWATER TREATMENT AND DISINFECTION ALTERNATIVES FOR THE

CHESAPEAKE BAY SEAFOOD PROCESSING INDUSTRY

Russell B. Brinsfield

Extension Agricultural Engineer Department of Agricultural Engineering

University of Maryland Cambridge, Maryland 21613

BACKGROUND

In 1972, Congress enacted the Federal Water Pollution Control Act Amendments. The objective of the Act is to re- store and maintain the chemical, physical, and biological integrity of the nation's waters. ,In order to achieve this objective, it is the national goal to eliminate the discharge of pollutants into navigable water by 1985.

In addition to the 1985 goal of no discharge of pollutants, a new interim national water quality goal is set for 1983-- the achievement of water quality which provides for "protection and propagation of fish, shellfish and wildlife and provides for recreation in and on the water."

Specifically, Section 301 of the Act sets deadlines for ascertaining certain levels of control from all major sources of pollution. The first deadline was July 1, 1977. By this date industrial sources of pollution must achieve the best practical control technology currently available" (BPCTA). This program sets national levels of pollution control based on the availability of technology.

The second deadline is set for July 1, 1984. By this date industries must utilize the "best available control technology economically achievable (BATEA). These technology- based standards apply to the effluent being discharged in order to attain the ultimate goal of "no discharge of pollutants." Plants with similar processes and design will be categorized and required to comply with the new federal standards regardless of their location.

In Maryland there are 47 seafood processing plants in areas where no municipal wastewater treatment facilities are available, thus requiring them to comply with the new federal standards. These seafood processing plants are the principal concern is this study.

All 47 of the processing plants are currently without

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access to publicly owned wastewater treatment facilities. Land suitable for disposal of wastewater, such as spray irrigation or overlandsiflow, is either severely limited or non- existent in nearly all cases. Since the plants are dispersed widely throughout the state, the options for collection and treatment in centralized facilities are reduced.

Seafood plants processing oysters, clams, and fish use potable water from on-site wells for washing raw products. Plants processing blue crabs use low pressure steam in crab cookers. During cooking, the steam condenses and combines with the crab body fluids to make up a significant portion of the waste flow from this type of plant. Due to the high cooking temperatures, this wastewater is considered to be free of most pathogens. In all plants, a second source of wastewater is generated during washdown and disinfection of food handling equipment and facilities. The flow ranges from approximately 7500 to 15100 1/d. Wastewater from the above sources is discharged to receiving water categorized as Class II--Shellfish Harvesting, or tributaries thereof. It is significant that none of the plants investigated permitted human wastes to enter the process wastewater stream, although some plants did have handwashing sinks connected to the wastewater stream.

The present requirements for treatment are set forth in the NPDES permit which is issued to each processor as a joint federal-state permit by the Maryland Water Resources"*" Administration, Department of Natural Resources. Maryland has been authorized by EPA to issue joint permits since September 1974. Permit requirements include: solids removal by 20-mesh screen, prohibition of floating solids or foam in effluent other than trace amounts, disinfection of effluent with resultant bacteriological quality not exceeding total coliform standards of 70 MPN per 100 ml, and effluent pH in a range of 6.0 to 8.5. The state also has a policy which sets an upper limit of 0.5 mg/1 residual chlorine for point sources discharging into tidal waters.

WASTEWATER CHARACTERIZATION

To determine the most economically feasible method of wastewater treatment and disposal for each seafood processing plant, base line data on volume and character of the wastewater were necessary for each processing operation. Because of basic similarities among the processing plants, it was decided to select at random several typical plants which processed one or more of the four predominant species: blue crabs, fish, soft-shell clams, or oysters.

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Specifically, six crab, five oyster, two fish, and five combination oyster and soft-shell clam processors were sampled weekly during their harvest seasons. The data from these operations served as a guide for grouping plants with similar problems.

For each plant sampled, the following specific tasks were performed:

1. Characterize the wastewater generated in a physical, chemical, and biological sense.

2. Determine the flow rate, volume of product processed, processing time, and specific operation occurring within the plant when the samples were taken.

3. Evaluate and recommend management practices which might reduce wastewater volume.

The samples collected were analyzed for settleable solids, tÊftal suspended solids (TSS), five-day biological oxygen demand (BOD5), oil and grease, residual chlorine, pH, phosphorous, nitrogen (NO2 and NO3), total Kjeldahl nitrogen, ammonia, coliform and fecal coliform.

No. of BPCTA (1977) BATEA (1984) Plants No. of Oil & Oil & Sampled Samples TSS Grease pH BODs TSS Grease pH

Blue Crabs 6 74 No Yes Yes No No Yes Yes (conventional process)

Fish 2 10 No Yes Yes No No Yes Yes (conventional process)

Atlantic 6 76 Yes Yes Yes N/A Yes Yes Yes Oysters (hand shucked) 4 40 No Yes Yes N/A No Yes Yes

Soft-Shell 5 41 Yes Yes Yes N/A Yes Yes Yes Clams (hand shucked)

TABLE I. Maryland seafood processors currently available to meet

EPA BPCTA (1977) and BATEA (1984) effluent Guidelines.^- !•Based on mean values of the indicated parameter from 18 processing plants sampled in 1975-76. "Yes" indicates current ability to meet guideline standards; "No" indicates not meeting guideline standards; ,,N/A"--not applicable.

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RESULTS AND DISCUSSION

Physical and Chemical Results

Table I sunnnarized the results of sampling for TSS, oil and grease, BODc and pH from the 18 plants. On the basis of this summary, the following conclusions can be reached regarding the various types of processes.

Blue crabs (conventional process). Based on 74 wastewater samples from six crab plants, ooth oil and grease and pH limits are currently being met for both BPCTA and BATEA. However, based on 62 samples analyzed, the TSS limits for BPCTA, as well as BODc and TSS limits for BATEA, are not being met in five of the six plants.

Fish (conventional process). Based on 10 wastewater samples from two fish processing plants, both oil and grease and pH limits for both BPCTA and BATEA are currently being met. How- ever, TSS limits for BPCTA and BOD5 and TSS limits for BATEA are not being met. However, both plants are locatf&d in areas for which municipal wastewater systems are presently in the design stage.

Atlantic oysters (hand shucked). Based on 76 wastewater samples from six oyster plants utilizing static screens, all of the EPA parameters for both BPCTA and BATEA are currently being met. However, based on 40 wastewater samples from four other oyster plants utilizing static screens, the TSS limits for both BPCTA and BATEA are not being met. This leads to the conclusion that if static screening is successful in reducing TSS in some plants, it should be possible to achieve the same results in other plants by minor improvements.

Soft-shell clams (hand shucked). Based on 41 wastewater samples from five clam plants, all of the EPA parameters are currently being met for BPCTA and BATEA.

Bacteria and Disinfection

Table II gives the geometric means for total coliform and fecal coliform. Residual chlorine levels found in the effluent samples are also included.

Maryland requires that wastewater from seafood processing plants be disinfected before discharge to tidal waters, since receiving waters are Class II-Shellfish Harvesting Waters. The bacteriological standards for these waters limit the total coliform organisms to 70 MPN per 100 ml as a median value, and not more than 10% of the samples may exceen an MPN of 230 per 100 ml for a five-tube decimal dilution test. The state also has an upper limit of 0.5 mg/1 residual chlorine level

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for point source discharging into tidal waters.

Geometric Mean Geometric Mean Residual No. of Coliform Fecal Coliform Chlorine

■ Samples MPN/100 ml MPN/100 ml Mg/1

Conventional Blue 74 1.8 x 103 159 88.6 Crabs - 6 plants sampled

Conventional Fish 10 79.5 x 103 175 0.1 2 plants sampled

Hand Shucked Clams^ 41 2.4 x 103 106 86.8 5 plants sampled

md Shucked Oystei 5 plants sampled

Hand Shucked Oysters2 63 4.6 x 103 60 29.3

Hand Shucked Oysters^ 53 6.7 x 103 232 49.1 5 plants sampled

TABLE II: Total,coliform, fecal coliform and residual chlorine data.

T! Based on geometric means of samples from 18 processing plants sampled in 1975-76.

2. These five plants alternate between processing oysters and soft shell clams.

3. These five plants process oysters only.

In the plants sampled, chlorine in the form of dry calcium hypochlorite was used to satisfy requirements for wastewater disinfection and sterilization of food handling equipment. Residual chlorine levels in the wastewater were consistently much higher than the 0.5 mg/1 allowed by Maryland. Concur- rently, very few of the plants sampled met the criterion of 70 MPN per 100 ml total coliform. The fact that high levels of total and fecal coliformwexe present in the wastewater streams from nearly all processing plants is one of the most significant findings of the study. The most probable reasons chlorine was ineffective in reducing bacteria to required levels are insufficient contact time and relatively large particle size of the suspended solids, even after screening.

In.addition to the high coliform levels, high residual chlorine levels are also alarming because of potential'detrimental effects to marine organisms with low tolerance. A recent report1 indicated that very few studies have been made of the effects of chlorine or residual chlorine in wastewater

Page 144

effluents on estuarine and marine fishes. One study2 discusses limitations as low as 0.002 mg/1 residual chlorine for the protection of most aquatic organisms. Another study-* reports test results indicating a medial tolerance limit (50% survival) for oyster larvae of 0.005 mg/1 residual chlorine in 48 hours under certain test conditions.

Disinfection Alternatives

Ultraviolet Radiation. It has been known for some time that ultravioletradiation can destroy all types of bacteria. Water sterilizers or purifiers utilizing mercury vapor lamps thatêmit a narrow band of radiant energy centered at 2.537 x 10 m^ (2537 A) wavelength are commercially available. Ap- plications include purification of potable water, food processing water, swimming pools, and wastewater. The degree of microbial destruction is a function of both exposure time and radiation intensity. The dosages required for most bacteria

fnn«7ln 6 ?rc^fr 20,000 microwatt-seconds per cm2. Since 1007o transmission may not occur, the system should provide exposure in excess of 30,000 microwatt-seconds per cm2. Turbidity and suspended solids (ss) require provision for a filtering unit as part of the system. Filters commercially available for this application include those employing dia- tomaceous earth. However, in the case of wastewater encountered in seafood-processing plants, it is believed that filtering

rr-i^rOSS ®usPenê<^ solids first, and then polishing the effluent with a second filter would be preferable to single- state filtering in order to reduce the frequency of back- washing the final filter.

During the summer of 1974, limited evaluation of an ultraviolet (UV) system for disinfection of wastewater from a Maryland seafood-processing plant was undertaken.* A filter utilizing fiberglass and charcoal was improvised and used in conjunction with fresh water dilution at a rate of 3 parts fresh water to 1 part effluent. The filter and dilution were necessary to reduce turbidity from about 300 JTU to ensure adequate UV penetration. The wastewater then passed through

unit which resulted in reduction of coliform from 43 x 10 MPN/100 ml to less than 3 MPN/100 ml. Concurrently there were substantial reductions in TSS and BODc. At the time this work was done it was estimated that a permanent commercial installation, with a capacity of 11,364 1/h, would cost approximately $3000. Since this flow rate exceeds that of any of the plants sampled, an investigation of availability of smaller units was made. UV sterilizers suitable for salt water having a capacity of 1,818 1/h are available for approximately $600, and with a capacity of 3.636 1/h for approximately $900. However, filters commercially available which would ensure a sufficiently clear effluent to obtain adequate micro- Dial kill are considerably more expensive than the UV units.

Page 145

The total cost of UV unit, filter, and installation costs would exceed $4000. It is believed, however, that a suitable mixed media or sand filter could be developed from relatively inexpensive readily available components and tailored to meet the needs of small seafood-processing plants for approximately $500. On this basis, a UV system including filter and installation could possibly be installed for about $1600.

SUMMARY

More recent concerns over possible detrimental effects of chlorine discharges into natural tidal waters resulted in a project to evaluate the potential effectiveness of UV in treating wastewater from a crab processing plant in a controlled laboratory environment. The objectives of the study are: (1) to purchase and install a laboratory sized UV disinfection unit in a model treatment system for a blue crab processing plant, (2) determine the effectiveness of UV in reducing bacterial counts, (3) study the interaction of water quality parameters and UV disinfection. It is believed that results of this study will aid the seafood processor in meeting EPA and the State of Maryland's water quality parameters as well as provide a viable alternative to chlorination.

Page 146

REFERENCES

1. Tsai, Chu-fa. 1975. "Effects of Sewage Treatment Plant Effluent on Fish: A Review of Literature." Chesapeake Consortium, Inc., Publication No. 36.

2. Brungs, W.A. 1975. "Effects of Residual Chlorine on Aquatic Life." Journal Water Poll. Control Fed., 45,2180.

3. Roberts, M.H., Jr., et. al. 1975. "Acute Toxicity of Chlorine to Selected Estuarine Species." Jour. Fish. Bd. Can., 32, 12 2525.

4. Joseph Lewandowski, Water Resources Administration, Maryland Department of Natural Resources, personal communication.

Page 147

CHLORINE USE IN BROILER PROCESSING PLANTS - STATUS QUO

Lewis E. Carr

Extension Agricultural Engineer Poultry Production Processing

Department of Agricultural Engineering University of Maryland Broiler Sub-sta.

Salisbury, Maryland

The topic for discussion is chlorine use in broiler processing plants — status quo. To understand why chlorine is used in broiler processing as a disinfectant, a brief review of the industry is in order. Since the industry is regional in nature comments in this paper will be directed toward the Delmarva broiler industry. If an east-west line is drawn through Dover, Delaware and Exmore, Virginia the area in between contains the majority of the broilers produced on Delmarva.

Table I shows some 1980 broiler production facts for Delmarva. These statistics represent approximately 15% of the national production in the United States to supply the 40 to 45 pound consumption rate per capita annually.

ANNUAL PRODUCTION - - - - 418 MILLION

HOUSE CAPACITY ------89.7 MILLION

PROCESSED VALUE ----- $706.3 MILLION

TABLE I: 1980 BROILER PRODUCTION FACTS FOR DELMARVA

The house capacity refers to the number of birds that can be housed simultaneously. An average of 4.6 flocks was produced resulting in an annual production of 418 million birds with a processed value of 706.3 million dollars. Taking into consideration the production area and the house capacity, Delmarva has more chickens per square mile than in any other part of the United States.

To understand how chlorine is used in the processing plant a look at some of the processes is a must. Figure 1 shows plant areas in a typical plant. Horizontal arrows leading

Page 148

RENDERING ♦ EFFLUENT TO

TREATMENT

FIGURE I - PLANT AREAS

Page 149

to the wash down line shows many processes that use water. Most of these have a continual water requirement. Water discharged from chillers and scalders may be used to transport feathers and offal to the offal collection area for primary treatment. This is where the solids are separated for rendering and the effluent sent to further treatment.

Broiler processing plants and products are inspected by the United States Department of Agriculture (USDA) inspectors. The inspectors in charge are veterinarians. Some plants may have more than one, depending on the size operation. In- spection requirements are set forth in the USDA Meat and Poultry Inspection Regulations with appropriate amendments. Paragraphs 381.45 through 381.61 show the sanitation requirements and criteria applicable to poultry processing.

Paragraphs 381.50 and 381.58 deal with water supply and the cleaning of equipment and utensils, respectively. Para- graph 381.50, Water Supply, states that:

"Water supply shall be ample, clean and potable A water report, issued under the authority

of the state health agency, certifying to the potability of the water supply shall be obtained by the applicant as required by the administrator

The first potential introduction of chlorine into the processing plant is through potable water. It should be noted that USDA does not determine the potability of the water used in processing. This is done by the state health agency which normally has chlorination responsibilities for water potability. Paragraph 381.58, Cleaning of Equipment and Utensils, states that:

"Equipment and utensils used for processing or otherwise handling any poultry product shall be kept clean, sanitary and in good repair."

After a plant is cleaned properly, a final sanitation wash is performed prior to a daily pre-operation inspection performed by USDA. Normally, chlorine is used in this sanitation wash at the rate of 20 ppm or 20 mg/1. However, it is not a USDA requirement. It is normally part of a plants program to prevent down time because of unsanitary conditions. If a plant does not pass its daily pre-operation inspection because of sanitation, the USDA inspector in charge will not permit the plant to begin its daily processing until the situation has been corrected to his satisfaction. This could idle 300-600 people for a period of time which becomes expensive to plant management. Therefore, to assist in assuring sanitary conditions after proper clean-up, a chlorine sanitation wash is

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normally used.

USDA has no chlorine requirement if regular non-automated processing is used. If automated processing equipment is used, there is a requirement to use 20 mg/1 chlorine. In further processing (chicken franks, rolls, etc.) a final rinse of 200 mg/1 for 30 seconds is common practice (not a USDA requirement) for sanitation purposes, Wabeck (1981).

USDA has established minimum water use requirements for scalders and chillers. There is a one (1) quart and two (2) quart overflow/bird requirement for the scalder and chiller respectively. The overflow requirements assist in the control of pathogenic organisms. The inspector in charge may increase the overflow rate from the minimum at his discretion.

As the effluent leaves the offal location in Figure 1 after primary treatment, it is further treated and disposed of by one of three methods. They are: municipal, multi-stage lagoon and spray_irrigation. (There are 5, 6 and 3 plants, respectively, using the methods described). If point discharge is involved, as in a multi-stage lagoon system, a final chlorination is required before discharge into public waterways. Table II shows the tri-state requirements for chlorination of point source discharge.

STATE RESIDUAL MAXIMUM MINIMUM

DE FREE CHLORINE 4.0 mg/1 1.0 mg/1

MD TOTAL CHLORINE 0.5 mg/1 ---

VA TOTAL CHLORINE 1.0 mg/1 0.5 mg/1

TABLE II: TRI-STATE REQUIREMENTS FOR CHLORINATION OF POINT SOURCE DISCHARGE (Moore, 1981)

The chlorine residual in Table II may be defined by the following equation:

TOTAL _ FREE UTILIZED CHLORINE CHLORINE CHLORINE

As shown, chlorination requirements differ on Delmarva.

Figure 2 shows the results of processing water use sur- veys conducted since 1973. Comparing the 1973 to 1981 average results, a 26 percent reduction in water used per bird has been achieved. The variations shown between maximum and minimum water use can be contributed to such things as inspectors de-

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cisions, the type processing used, plant design, etc.

DELMARVA POULTRY PROCESSING

WATER USE

APR 1 1 DEC 1977 1977

DATE OF SURVEY

This paper has been devoted to the status quo use of chlorine in broiler processing. Chlorine use in broiler processing is voluntary in some instances and not in others. Experience has shown that most of the chlorine used in the processing plant is combined with the proteinaceous material in the effluent. Chlorine at a lagoon discharge point into public waterways is a result of added chlorine to meet state requirements. Since 1973, the industry on Delmarva has made considerable progress toward reducing the amount of water used. With a reduction in water volume, there is a similar reduction in chlorine requirements, per bird, for the treated effluent at the point of discharge into public waterways.

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REFERENCES

1980 Broiler Production Facts. 1981. Delmarva Poultry Industry, Inc. Georgetown, DE.

Moore, Ralph. 1981. Personal Communication.

Wabeck, Charles. 1981. Personal Communication.

USDA Meat and Poultry Inspection Regulations with Amendments. USDA, Washington, DC.

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THE USE OF CHLORINE AND POTENTIAL ALTERNATIVES IN THE TRI-STATE VEGETABLE PROCESSING INDUSTRY

Donald V. Schlimme, Jr.

Department of Horticulture University of Maryland

College Park, Maryland 20742

A survey conducted by the National Food Processors Association (NFPA), published in 1978, estimates the total area of waste disposal sites controlled by vegetable, fruit, and specialty product processors in the United States as: 6,000 acres of wastewater ponds, 40,000 acres of wastewater irrigation sites, and 3,000 acres of solid waste disposal sites.

Just over 100 billion gallons of wastewater are discharged by fruit, vegetable, and speciality product plants per year. About forty percent of the processing plants rely primarily on spray irrigation disposal, forty percent discharge to city sewer systems, and twenty percent treat their own wastewater before discharge to water bodies.

According to Dr. Herb Brodie, a University of Maryland agricultural engineer with expertise in cannery waste disposal, no fruit or vegetable processor on the Del-Mar-Va Peninsula is discharging plant wastes, plant clean-up water, or food transport wastewater directly into the Bay or its estuaries or fieeder streams. On the eastern shore chlorinated, vegetable processing plant wastes are currently either discharged to municipal sewage treatment systems or discharged to lagoons for primary and secondary treatment and ultimate disposal onto agricultural land.

The vegetable processing industry is regulated by the FDA and must comply with the so-called umbrella Food Manufacturing Practices of Title 21 Code of Federal Regulations Part 110. Specifically, Part 110.37(c) of these regulations states in-part: Mall utensils and product contact surfaces shall be cleaned and sanitized prior to use or on a predetermined schedule using adequate methods for cleaning and sanitizing. Sanitizing agents shall be effective and safe." Part 110.80 readsîn-part: ^"processing equipment shall be maintained in a sanitary condition through frequent cleaning including sanitization whereîndicated. Equipment shall be taken apart for thorough cleaning. All food processing should be conducted under controls to minimize the potential for undesirable bacterial or other microbiological growth, toxin formation, or contamination of the processed product or ingredients.

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Geotrichum candidum, commonly referred to as "machinery mold" is a ubiquitous mold in vegetable processing establishments. Fruit sugars and acids and vegetable starches are preferred nutrients for machinery mold. Considered by itself, it has no public health significance. However, machinery mold is used by regulatory inspectors as a rough index of plant sanitation. Geotrichum becomes visible when counts approach 15,000 per square inch of equipment surface. Visible Geotrichum is considered evidence that food processed through the equipment has been prepared and processed under insanitary conditions, and is therefore adulterated.

In order to maintain levels of Geotrichum considerably below 15,000 per square inch of equipment surface, it is necessary to:

1) Clean, wash, and sanitize incoming raw product. 2) Use chlorination (2 to 7 ppm CI2 water sprays) on equip-

ment product contact surfaces on a continuous basis during plant operation.

3) Chlorinate product transport waters to a level of 2 to 7 ppm CI2.

4) Schedule total plant shut-down and completely clean, all disassembled equipment at least once each 24 hours. This entails the use of detergents followed by a rinse a,nd then treatment with 50 to 200 ppm CI2 solutions" to sanitize all surfaces of all equipment.

5) Use a germicide in all finished product cooling waters to prevent post-processing contamination of containers.

In-plant chlorination is necessary to reduce the microbial population on raw materials and processing equipment to "adequate levels of sanitation" and, thereby, to preclude adulteration of finished products with "filth". Thus, raw materials are washed with chlorinated water to remove soil and surface contamination. The water used to convey raw materials between and through unit operations contains 2 to 7 ppm of free residual chlorine if it is not recycled and up to 10 ppm if it is recycled. The sanitizing agent must be FDA approved for direct contact with food materials, and it must be capable of being totally removed by rinsing with potable water. Chlorine dioxide is often used to sanitize recycled transport water because it is less reactive with organic material and does not readily form chloramines.

Chlorine and related chlorine compounds are by far the most commonly used sanitizing agent in vegetable.processing establishments. Gaseous CI2 and, to a considerably lesser extent, sodium or calcium hypochlorite are most frequently used. Chlorine dioxide is used primarily for sanitizing recycled product transport waters. Chloramines, such as Sterichlor, Azochloramide and Dichloramine-T, are occasionally used to

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sanitize the inside surfaces of large storage vessels where a long contact time is preferred.

Regardless of the source of free residual chlorine, such as gaseous CI2, hypochlorites or chlorine dioxide, the specific uses and common concentrations of chlorine have been identified by Cleve Denny of NFPA's Washington Laboratory as follows:

Use Range

Container cooling water 0.5 - 10.0 ppm Water for product transport 0.5 - 7.0 ppm Recycled water 0.5 - 10.0 ppm Conveyor & inspection belt sprays 3.0 - 15.0 ppm Rinse & spray water 1.0 - 5.0 ppm Plant clean-up water 2.0 -125.0 ppm Water for sanitizing disassembled

equipment 100.0 -200.0 ppm

According to Denny, the use of chlorine as a sanitizing agent in the vegetable processing industry though extremely wide-spread, is essentially self-limiting. First, residual chlorine levels in waters used to prepare syrups, brines, and other packing media are minimal because high levels result in objectionable off-flavors in finished products. Second, high levels of chlorine corrode metal equipment. The canner, therefore, has every incentive to maintain in-plant chlorination at levels that achieve the desired germicidal effect but do not adversely affect the product or equipment.

The National Food Processors Association laboratories have spent years of research trying to find a germicide for use in food processing establishments which is more effective than chlorine. The results of this research indicate that:

a. Iodine compounds, the so-called iodophors, are not as effective and are much more toxic than chlorine. Further- more, their presence in trace residue amounts on food products could be considered as adulteration by FDA.

b. Quartemary ammonium compounds are amines and are much more toxic than chlorine. Furthermore, the presence of "Quats" on food products would be considered as adulteration by FDA.

c. An aqueous solution of dodecylbenzenesulfonic acid is permitted as a sanitizing agent by FDA, but it is far less effective than chlorine.

d. Hot hydrogen peroxide is the fastest acting germicide, but its use would be too expensive except for speciality use, such as the sterilization of plastic containers used

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in aseptic processing operations.

e. Ultraviolet light penetrates only surface layers of target material and cannot sanitize multi-surfaced processing equipment, raw product material, or even large volumes of turbid food transport water.

f. Ethylene oxide is an effective germicide, but it is slow acting, requiring an exposure time of hours at room temperature. Furthermore, its reaction compounds are being questioned as possible carcinogens.

g. Ozone is an effective germicide, although it is not as economical as chlorine for sanitization of vegetable processing plants. Its ultimate use for this purpose awaits the outcome of experimental studies of its efficacy.

h. At this time, the American vegetable processing industry has no effective, economical substitute for chlorine as a sanitizing agent for use in day-to-day processing operations.

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ALTERNATIVES TO CHLORINATION FOR CONTROLLING BIOFOULING IN COOLING WATER SYSTEMS OF STEAM

ELECTRIC GENERATING STATIONS

Dennis T. Burton Lenwood W. Hall, Jr.

The Johns Hopkins University Applied Physics Laboratory

Aquatic Ecology Section Shady Side, Maryland 20764

ABSTRACT

A number of chemical and nonchemical techniques have been proposed as alternatives to chlorination for prevention of biofouling in both once-through and recirculating cooling systems of. power plants. The most reasonable alternatives for biofouling control in the condenser systems of once- through power plants in the Chesapeake Bay area are 1) the Amertap system; 2) intermittent chlorination followed by dechlorination and 3) possibly intermittent bromochlorination in freshwater and low salinity estuarine water. A number of additional alternative control measures exist for recirculating condenser systems. The most promising alternative for biofouling control of macrofouling organisms in the precondenser sections of once-through estuarine cooling water systems are 1) low level continuous chlorination followed by dechlorination; 2) possibly low level continuous bromochlorination in low salinity waters; 3) the use of water'' velocities above 1.5 m/sec which appear to reduce setting and/or growth of various fouling organisms and 4) possibly the use of heat in single and double-pass condenser operations. Control methods for the newly introduced Asiatic clam (Corbicula) in Virginia-Maryland freshwater precondenser structures include a number of alternatives such as mechanical straining and heat treatment.

INTRODUCTION

Biofouling in cooling water systems is a complex phenomenon which can result in costly decreased operating efficiency of power plants. Most power stations use chlorine to control fouling in their cooling water systems (Burton, 1980). However, because a number of studies have shown that chlorine and its residual by-products may be toxic to aquatic organisms (see review by Hall et al., 1981a), several alternatives to chlorine have been considered by utilities to reduce aquatic impact.

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To better appreciate how alternatives to chlorine may be employed at power plants, it is helpful to understand the problems of biofouling in cooling water systems and how chlorine is now used to control fouling. Therefore, a brief discussion of biofouling control by chlorine will be presented, followed by biofouling control alternatives to chlorine.

PROBLEM AREAS OF BIOFOULING

The major fouling problem at most power plants is the growth of slime on the heat transfer surfaces in the condensers. Condenser slime problems are found in power stations with once- through and recirculating cooling water systems.

Biofouling in the precondenser sections of cooling water systems (the portion of a cooling water system from intake to condenser tube sheets) with once-through or recirculating designs is not a problem in most freshwater plants with some exceptions, such as the blockage of condenser tubes by the Asiatic clam (Corbicula). Biofouling in the precondenser cooling water structures of estuarine and marine plants is a severe problem in many plants, particularly those with water flow velocities of approximately 1.5 m/sec or less which is optimal for the growth of many fouling organisms. High flow velocities tend to have a beneficial antifouling effect since at high flow rates the shear stress of the water often exceeds the shear strength of many setting fouling organisms, hence, they are swept away. The growth of slime and algae in open cooling towers is a biofouling problem which has to be treated in freshwater and marine plants.

CURRENT USE OF CHLORINE IN BIOFOULING CONTROL

Freshwater Plants

Fouling problems vary greatly from plant to plant because of differences in water quality and power plant design (Cole, 1977). Therefore, it is difficult to state exactly what the chlorination levels, frequencies and durations are or should be for all plants. Typically, large modem plants will chlorinate at regular intervals 2-4 times per day for periods which range from 15 to 30 minutes per application. This is adequate to control slime in the condensers. Chlorine is not generally used to control fouling in low-velocity areas of freshwater plants because fouling by higher organisms is not usually a problem. When a problem like the Asiatic clam does occur, other techniques such as mechanical cleaning and back- flushing are used (Gross and Cain, 1977).

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There are two fouling problems associated with recirculating cooling water systems, namely slime accumulation in heat exchangers and slime plus.algae on structures in the cooling tower. Both can usually be controlled by intermittent chlorination 2-3 times per day. In many cases the frequency of treatment is much less and may be associated with supplemental chemical treatments to control scaling or rotting of wood surfaces in the cooling tower. The duration of the normal chlorine treatment for a recirculating system with a cooling tower is usually 5-10 minutes longer than the turnover time of the water in the system which is about 20-30 minutes for the modem power plant (Draley, 1977).

Estuarine and Marine Plants

The slime problem in once-through salt water cooling systems is similar to that in freshwater systems. Intermittent chlorination will usually keep the condenser free of slime. However, intermittent chlorination does not control many components of primary, secondary and adventitious fouling communities which may be present in low velocity areas of the cooling system. Low level continuous chlorination is used in many cases to control fouling organisms in low velocity areas. This in turn controls the slime in the condenser system.

Slime and algal control in large salt water cooling towers has not been studied in detail because, until recently, no large cooling towers used salt water as makeup water. Limited experience at Potomac Electric Power Company's (PEPCO) Chalk Point Generating Facility, located on the Patuxent River in Maryland, has shown that low-level continuous chlorination is effective in controlling cooling tower fouling problems.

ALTERNATIVES TO CHLORINATION

A number of chemical and nonchemical techniques have been proposed as alternatives to chlorination for prevention of biofouling in both once-through and recirculating cooling systems of power plants (Burton and Liden, 1978; Waite et al., 1978; Burton, 1980; Garey, 1980 and Waite and Fagan, 1980). Some of the alternatives have been designed to specifically treat the condenser system and/or the precondenser structures (e.g., trash rakes, conduits, water boxes, etc.). Several suggestions put forth by various engineering firms and utilities have not yet been evaluated to establish their efficiency, costs, feasibility for retrofitting in existing plants and possible use in peak smoothing and base-lpad generating schemes. Several alternatives can be eliminated at the present time for one or more reasons,

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however, the currently feasible as well as speculative alternatives for possible future use will be briefly discussed to show the potential range of possible alternatives.

The major alternatives may be grouped into three broad categories (Table 1). Two categories are chemical antifouling agents (other than chlorine) and nonchemical fouling control techniques. Various combinations of these techniques are feasible. This is particularly true in estuarine and marine systems where fouling may be a problem in the condenser and precondenser cooling water structures. The third category is the detoxification of chemical antifouling agents such as dechlorination using sulfur dioxide.

Chemical Antifoulants: Oxidizing Agents

Several of the strong oxidizing chemical antifoulants are effective biofouling control agents. However, most have not proven satisfactory for use in large cooling water systems. Of the seven shown in Table 1, bromine chloride and ozone, to a lesser extent, have been identified as the most likely candidates for possible use in power stations located on freshwater and low-salinity systems.

Bromine chloride has been tested in intermittent application for condenser biofouling control at Public Service Electric and Gas Company's Marion Generating Facility located on the tidal portion of the Hackensack River in New Jersey (Wackenhuth and Levine, 1977). It is as effective as chlorine on an equal-weight basis. Bromine chloride was also tested on a low level, continuous basis for control of fouling in precondenser water structures and condensers at PEPCO's Morgantown Generating Station located on the Potomac River in Maryland (Bongers et al., 1977). On an equal weight basis, the continuous , low level application of bromine chloride was as effective a control as chlorine in all portions of the cooling water system.

Bromine chloride may be more desirable than chlorine in fresh and low salinity waters because bromine chloride residuals dissipate faster than chlorine residuals (Mills, 1980). Also, bromine chloride residuals may be less toxic to aquatic organisms than chlorine residuals in fresh and low salinity waters (Liden et al., 1980). The toxicity of bromine chloride in high salinity estuarine and marine water has not been tested. Evidence presented by Helz in this proceeding indicates that it may be similar to chlorine since the chemistry of all strong oxidizing agents may be similar in salt water.

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Research, Inc., 1976 and Sugam et al., ±980). However, several problems must be resolved before ozone can be considered a viable alternative to chlorine in large cooling systems. The most difficult engineering problem is that of providing a good contacting system for efficient mixing of ozone in the cooling wa-ter. Also, ozone must be generating onsite. There are conflicting reports regarding capital and operating costs of an ozonization plant. This is probably because ozonization cost is a function of plant size, place of manufacture, and the quality and quantity of water to be treated (Yu et al., 1977).

Ozone is highly toxic to freshwater organisms, however, because it is so unstable in freshwater, it degrades very . quickly. Thus, it appears to be a good alternative in freshwater if the cooling system is designed to allow degradation to occur before discharge. As in the case of bromine chloride, ozone is not a good alternative to chlorine in estuarine and marine waters. Burton and Richardson (1981) have shown that ozone-produced oxidants are very similar in toxicity to chlorine residuals to several estuarine invertebrates and fish.

Chemical Antifoulants: Nonoxidizing Agents

Nonoxidizing agents are used primarily in cooling towers, acting as wetting agents, wood preservatives and descaling agents. Some are used when chlorine proves to be ineffective in controlling fouling because of high chlorine dt md or when high concentrations of inorganic salts (which form scales) are present. Many of the nonoxidizing chemicals are extremely toxic to aquatic organisms (Becker and Thatcher, 1973 and U.S. Nuclear Regulatory Commission, 1975) and, for this reason alone, are not good alternatives to chlorine, except for special applications. Some are prohibitively expensive for use in once-through systems. Because nonoxidizing agents are not considered good alternatives to chlorine for general use in cooling water systems, this group will not be discussed' further.

Chemical Antifoulants: Miscellaneous

Several miscellaneous chemical antifoulants exist. Condenser biocide soaking is a proposed chemical "soaking process" that entails shutdown and flooding of the condenser system with a biocide (Marine Reserach, Inc., 1976). After the slime is killed, the chemical would be pumped out of the condenser and stored for future use. One obvious disadvantage is that the condenser would be shut down frequently with subsequent loss of generating time.

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Antifouling coatings and paints are made of various organ- ometallic compounds, copper oxides, pesticides, etc., in- corporated into vinyl-chlorinated rubber, coal-tar epoxy and other types of paint bases for use primarily on precondenser structures. The mode of action is a slow release into the water of one or more antifouling agents that inhibit or kill attaching organisms. Some of the newer control-release paints may be effective for several years. Application of these coatings to cooling water structures is being considered for both open and closed systems. Further studies are needed, however, for open systems to evaluate fully the possible impacts to aquatic organisms, particularly benthic organisms which may accumulate the released materials.

The Cathelco system is electrolytic in action which uses sacrificial copper anodes on which a low voltage current is impressed to release copper ions (Blume and Kirk, 1980). An aluminum anode is also used in conjunction with copper to form an aluminum hydroxide gelatinous matrix which picks up copper ions as they are liberated. This forms a stable complex which leads to an artificially high concentration of copper ions which line the cathode, i.e., the surface to be protected from fouling. The copper ions serve as the toxicant to deter the fouling organisms. A preliminary pilot study of the Cathelco system is presently being conducted at PEPCO's Chalk Point Generating Station. As :• the case of antifouling paints, we feel further studies are needed to evaluate fully the possible detrimental impact to aquatic organisms.

Nonchemical Fouling Control Techniques; Thermal

Southern California Edison (SCE) has used heated water to control marine fouling in the intake and discharge conduits of their coastal generating stations since the early 1950s. The power stations are designed so that heated discharge water can be recycled through the condenser to pick up additional heat. The water flow is reversed through both the intake and discharge conduits which are treated separately for 2 hour periods at 520C. The entire process takes about 8 hours and is performed at 5 to 6 week intervals. The process is reported to be quite successful; however, it does discharge high-temperature water to the environment which could be a problem in some Chesapeake Bay tributaries. Condenser tube slime control is accomplished in SCE plants by intermittent chlorination three times daily.

Heating soaking of condenser systems has been proposed for fouling control (Anderson et al., 1975). In this process, the condenser is drained while maintaining temperature on the steam side, creating a dry-heat soak (55 to 600C) for 2 hours.

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Although the slime layer is effectively killed, the residue is retained as a balced-on scale which unfortunately reduces condenser heat transfer efficiency.

Nonchemical Fouling Control Techniques: Nonthermal Energy

Nonthermal energy antifouling techniques, such as gamma irradiation and ultraviolet radiation, have been proposed as possible antifouling alternatives because of their success in killing microorganisms. The engineering feasibility of effectively irradiating large volumes of water with gamma rays has not been developed sufficiently to consider its use in large-scale systems, not to mention the cost.

Similar arguments can be made for ultraviolet radiation. Small amounts of organic and inorganic matter will act as a shield to UV radiation thereby reducing its effectiveness. Because of the sediment loads normally present in surface waters, UV radiation for large scale use in power plants does not appear to be a viable alternative at this time.

Ultrasonic cleaning techniques have been used with some success to prevent barnacle fouling on ship hulls, however, persistent slime films still occur. The fact that slime films cannot be inhibited on ship hulls by a broad range of frequencies and durations suggests that this alternative will not effectively prevent slime formation in condenser systems. An ongoing study at The Johns Hopkins University's Applied Physics Laboratory assessing the use of ultrasound to prevent the growth of the colonial hydroid, Gavveia (formerly Bimeria') , indicates that ultrasound may be useful in preventing the growth of this hydroid in precondenser structures. Garveia is a serious problem in the approach conducts of some Maryland power stations because it breaks off in large mats which subsequently restrict or block the flow of cooling water through the condenser tubes. At the present time, continuous chlorination (24 hr/day) is used to inhibit the growth of this fouling organism during its growth season (May - October).

Nonchemical Fouling Control Techniques: Hydraulic

An increase in the velocity of water moving through the precondenser components, of estuarine cooling systems may be a good fouling control method because velocities above 1.5 m/sec inhibit setting of various fouling organisms. This technique has been reasonably successful in controlling precondenser fouling at Baltimore Gas and Electric Company's Calvert Cliffs Nuclear Power Plant located on the Chesapeake Bay in Maryland.

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Water jet cleaning is frequently used for.manually cleaning heat transfer surfaces. It has been proposed that water jet nozzles be placed permanently in cooling systems and used automatically when fouling becomes a problem (Conn et al., 1977). The engineering feasibility of this method during normal plant operations has not been demonstrated.

Nonchemical Fouling Control Techniques: Mechanical

Mechanical means of cooling system cleaning are viable alternatives to chemical antifoulants. The most obvious method is manual cleaning which requires long plant downtime. Two types of automatic manual condenser cleaning systems which can be used during normal plant operations are the Amertap and American Tube Cleaning System (ACTS; formerly American M.A.N. system).

The Amertap system is the most common type of automatic mechanical cleaning system. By circulating oversize sponge rubber balls through the condenser tubes with the cooling water, the inside of the condenser tubes are wiped. The balls are collected in the discharge water box by screens and repumped to the inlet of the condenser for another pass through the system. They can be.used intermittently or continuously.

The ATCS uses flow-driven brushes which pass through the condenser tubes intermittently by reversing the flow of condenser cooling water. The brushes abrasively remove fouling and corrosion products. Between cleaning cycles the brushes are held in baskets attached at both ends of each tube in the condenser.

The Amertap and, to a lesser- extentthe .ATCS have been reasonably successful in maintaining condenser efficiency and reliability. Some problems are abrasion and grooving of condenser tubes; in some cases the systems themselves become fouled and must be cleaned.

Nonchemical Fouling Control Techniques: Miscellaneous

Several other nonchemical fouling control techniques have been proposed. However, since many are not feasible or practical from an engineering point of view, only a few will be mentioned, omitting the unrealistic proposed techniques.

Osmotic shock involves the use of freshwater to kill marine fouling organisms in precondenser cooling water structures. It would entail closing a cooling water system down, flooding it with freshwater and letting the water remain

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in the system for several days to kill the organisms. A plant using this technique must have duplicate precondenser cooling systems.

Anoxic water involves shutting a system down and letting the water go anaerobic for several days to kill the fouling organisms. Like the osmotic shock technique, it requires a duplicate cooling water system. The anoxic water treatment could be used in fresh or marine systems.

Detoxification of Chemical Antifoulants: Chemical and Physical Methods

Detoxification of chlorinated effluents is a viable alternative for reducing chlorine toxicity to aquatic organisms. Chlorine and many of its derivatives can be removed by activated carbon, aeration or the addition of thiosulfates, sulfites and sulfur dioxide. Such methods as aeration and activated carbon filtration appear to be feasible techniques for dechlorinating cooling tower blowdown.

I

Several agents, e.g., sodium sulfate/sulfite and sulfur dioxide, can be used to dechlorinate large volumes of water from once-through cooling systems. Sulfur dioxide is particularly promising for large-scale use. The handling and metering of sulfur dioxide is very similar to that of chlorine. Several dechlorination studies with sulfur dioxide have shown significant reductions in chlorine toxicity to a variety of freshwater organisms. Limited studies with organisms indicate that sulfur dioxide will reduce acute chlorine toxicity when it is properly mixed with chlorinrr'od water. However, it has been shown that dechlorinated est nne and marine waters may contain chlorine by-products which may be slightly toxic or cause behavioral changes in certain aquatic organisms (Hamel and Garey, 1980 and Hall et al., 1981b). Further studies in estuarine and marine systems shovil be conducted to clarify these observations.

ACKNOWLEDGMENT

We thank Beverly Knee for typing original manuscript.

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REFERENCES

Anderson, M.R., R.M. Vaccaro and R.C. Toner. 1975. A new concept in power plant operation to control slime bacteria in electric condenser cooling systems. Paper presented at the Workshop on the Assessment of Technological and Ecological Effects of Biofouling Control Procedures at Thermal Power Plant Cooling Water Systems, June 16-17, 1975, The Johns Hopkins University, Baltimore, MD.

Becker, C.D. and T.O. Thatcher. 1973. Toxicity of power plant chemicals to aquatic life. Pages 1-10 & Section A-R in Rep. No. WASH-1249, U.S. Atomic Energy Commission, Washington, DC.

Blume, W.J. and B.J. Kirk. 1980. Application of the Cathelco antifouling system for the control of marine growth in seawater inlets and condensers. Pages 471-486 in J.F. Garey, R.M. Jordan, A.H. Aitken, D.T. Burton and R.H. Gray, eds. Condenser biofouling control. Ann Arbor Science Publishers, Inc., Ann Arbor, MI.

Bongers, L.H., T.P. O'Connor and D.T. Burton. 1977. Bromine chloride - An alternative to chlorine for fouling control in condenser cooling systems. Rep. No. EPA-600/7-77-053, U;S. Environmental Protection Agency, Washington, DC. 163 pp.

Burton, D.T. 1980. Biofouling control procedures for power plant cooling water systems. Pages 251-266 in J:F. Garey, R.M. Jordan, A.H. Aitken, D.T. Burton and R.H. Gray, eds. Condenser biofouling control. Ann Arbor Sciences Publishers, Inc., Ann Arbor, MI.

Burton, D;T. and L.H. Liden. 1978. Biofouling control alternatives to chlorine for power plant cooling water systems: An overview. Pages 717-734 in R.L. Jolley, H. Gorchev and D.H. Hamilton, Jr., eds. Water chlorination environmental impact and health effects, Volume 2, Ann Arbor.Science Publishers, Inc., Ann Arbor, MI.

Burton, D.T. and L.B. Richardson. 1981. An investigation of the chemistry and toxicity of ozone-produced oxidants and bromate to selected estuarine species. Rep. No. EPA-600/4-81-040, U.S. Environmental Protection Agency, Washington, DC. 65 pp.

Cole, S.A. 1977. Chlorination for the control of biofouling in thermal power plant cooling water systems. Pages 29-37 in L.D. Jensen, ed. Biofouling control procedures technology and ecological effects. Marcel Dekker, Inc.,

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New York, MY.

Conn, A.F., M.S. Rice and D. Hagel. 1977. Ultra clean heat exchangers - A critical OTEC requirement. Pages 3C-

-1 " ^ Proceedings of the Papers Presented

1 Energy ConverSion Conference, March 22-24, 1977, New Orleans, LA.

Draley J.E. 1977. Biofouling control in cooling towers and closed cycle systems. Pages 23-28 in L.D. Jensen, ed. Biofouling control procedures technology and ecolosical effects. Marcel Dekker, Inc., New York, NY ô-Logâl

Garey J.F 1980 A review and update of possible alternatives

to chlonnation for controlling biofouling in cooling water systems of steam electric generating stations. Pages 453-467 in R.L. Jolley, W.A. Brungs and R.B. Gumming eds Water chlorination environmental impact and health effects Volume 3, Ann Arbor Science Publishers, Inc., Ann Arbor, MI.

Goss, L.B. and C. Cain, Jr. 1977. Power plant condenser and

service water system fouling by Covbicula , the Asiatic clam. Pages 11-17 in L.D. Jensen, ed. Biofouling

control procedures technology and ecological effects, Marcel Dekker, Inc., New York, NY.

Hall, L.W., Jr., G.R. Helz and D.T. Burton. 1981a. Power

? nA oât:^0n a, biological and chemical assessment. Ann Arbor Science Publishers, Inc., Ann Arbor, MI. 237 pp.

Hall, L.W., Jr. D.T. Burton, W.C. Graves and S.L. Margrey. 1981b Effects of dechlorination on early life stages of striped bass (Movone saxatilis ). Environ. Sci. Technol. 15:573-578.

Hamel, A.R. and J.F. Garey. 1980. Dechlorination a caution. Pages 419-428 in J.R. Garey, R.M. Jordan A.H Aitkin, D.T. Burton and R.H. Gray, eds. Condenser biofouling control. Ann Arbor Science Publishers Inc Ann Arbor, MI. '

Liden, L.H., D.T. Burton, L.H. Bongers and A.F. Holland. 1980. Effects of chlorobrominated and chlorinated cooling waters on estuarine organisms. J. Water Pollut. Control Fed. 52:173-182.

Marine Research, Inc. 1976. Final report on possible alternatives to chlorination for controlling fouling in power station cooling water systems. Marine Research Inc., Falmouth, MA 243 pp.

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Mills, J.R. 1980. Bromine chloride - An alternative to chlorine for treatment of once-through cooling waters. Pages 463-469 in J.F. Garey, R.M. Jordan, A.H. Aitken, D.T. Burton and R.H. Gray, eds. Condenser biofouling control. Ann Arbor Science Publishers, Inc., Ann Arbor, MI.

Sugam, R., C.R. Guerra, J.L. DelMonaco, J.H. Singletary and W.A. Sandvik. 1980. Biofouling control with ozone at the Bergen Generating Station. Rep. No. EPRI CS-1629, Electric Power Research Institute, Palo Alto, CA 132 pp.

U.S. Nuclear Regulatory Commission. 1975. Chemical alternatives to chlorine for biofouling control. Docket No. 50-460, Sect. 4, U.S. Nuclear Regulatory Commission, Washington, DC. 24 pp.

Wackenhuth, E.C. and G. Levine. 1977. Experience in the use of bromine chloride for antifouling at steam electric generating stations. Pages 63-78 in L.D. Jensen, ed. Biofouling control procedures technology and ecological effects. Marcel Dekker, Inc., New York, NY.

Waite, T.D. and J.R. Fagan. 1980. Summary of biofouling control alternatives. Pages 441-462 in J.F. Garey, R.M. Jordan, A.H Aitken, D.T.Burton and R.H. Gray, eds. Con- denser biofouling control. Ann Arbor Science Publishers, Inc., Ann Arbor, MI.

Waite, T.D., R.M. Jordan and R. Kawaratani. 1978. Evaluation of alternative chemical treatments for biofouling control in electric power facilities. Pages 753-771 in R.L. Jolley, H. Gorchev and D.H. Hamilton, Jr., eds. Water chlorination environmental impact and health effects, Volume 2, Ann Arbor Science Publishers, Inc., Ann Arbor, MI.

YU, H.H.S., G.A. Richardson and W.H. Hedley. 1977. Alter- natives to chlorination for control of condenser tube bio-fouling. Rep. No. EPA 600/7-77-030, U.S. Environ- mental Protection Agency, Washington, DC. 75 pp.

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DISCUSSION OF ALTERNATIVES

Sewage Treatment

Q: Are there any dissolved oxygen problems with use of sulphur dioxide?

A: We have not experienced any major problems. I have gone around to many of the plants in which we dechlorinate and . found no significant decrease in dissolved oxygen. It was anticipated as was a decrease in PH. We have not found it in the levels that we use. Maybe with a large overdose you will get a depression in dissolved oxygen.

Q: Is there a way of easily and effectively controlling your chlorination so you would not need dechlorination?

A: There is no way to control chlorination to the point that we are limited. We are limited down to levels which are essentially zero. With the basic design of waste water plants now, no, there is no way we can get it down to that level without dechlorinating.

Q: Why can't we use European knowledge to improve our treatment programs?

A: I hope we have, but I guess part of the problem is Americans like to do things themselves and learn their own way. Several people, some prominent individuals, have been traveling to Europe trying to learn what they know and bring this back to our country, but it's a slow process.

Merilyn Reeves: You indicated that ozone is in keen competition with suspended solids and chemical oxygen demands. And you also indicated that there is a problem in the contact chamber of getting the design bugs out. Are these not very similar problems to the use of chlorine in that we obviously have not gotten the design of a chlorine contact chamber down in the waste water treatment plants to the point where we have it in the facilities. Also is it not true that with chlorine you have the same kind of competition as you described for ozone if you have high suspended solids or high chemical oxygen demand?

A: Yes, this is true. If you have a tertiary treatment facility with a low BOD and low suspended solids, the chlorine required would be less. By the same token, the amount of ozone required to disinfect would be lower. If we have a secondary effluent where we have BOD and suspended solids, it will require more ozone. By the same token, it will re-

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quire more chlorine.

Ms. Reeves: So that the characteristics of the use of both ozone and chlorine, in terms of having good secondary treatment or good treatment processes, would be the same and you would have comparable kinds of characteristics in the design of chlorine contact chamber. Not that they are designed the same, but that you must design for the use of that particular product. Would that be a fair assumption for both of them then?

A: I think so, but with chlorine or ozone you have to design the contact chamber so that the disinfectant gets to the bugs. If you have a poor design it won't happen. If you have a good design, then you'll get disinfection in either case.

Ms. Reeves: I have a lot of problems with how the chlorine contact chambers have been designed. It seems to be a flaw that we have been using chlorine at great length yet we do not have adequately disinfectant chambers, so the problem in designing for ozone is that we have to start all over again anyway with chlorine to do it right.

Dr. Gottschalk: Are there any statistics on how many plants are currently using ozone in this country?

A: Probably in the neighborhood of 10 to 20 plants in this country now. There are a lot of plants that are very close to being on line.

Dr. Gottschalk: Of the treatment plants in the United Stated, how many are currently using ozone?

Bruce Burns: One-tenth of 17o of thousands of treatment plants in the country.

Q: I believe that you mentioned that there was no known toxic by-products from the use of ozone. Is this true in salt water? I had heard that when you discharge your effluent into salt water, bromines are formed if there is ozone used in the disinfection.

Mr. Burns: I'm not aware of that but it may very well be.

Q: Is there any practical limit to what flow can be treated by UV?

Karl Schieble: I don't think there is any limitation to that. As you saw, that was a 6MGD Plant. It needed two chlorine contact chambers. We took approximately 5% of the space

/ Page 172

that was available in those chlorine contact chambers and treated the total plant flow. So retrofitting is not a problem in terms of size. Madison is going to be a 125MGD Plant with UV.

Q: How effective would UV be on a secondary plant that is discharging in the 30-30 range?

Mr. Schieble: I do not think there is going to be a problem. As I said, there are ways of handling that now. We can modify the design aspects of UV system by spacing lamps and accounting for any high absorbances. At New York City the work that we anticipate over the next few years is going to look at combined sewer overflow waste waters and also at a secondary effluent that is more in the range of the 30-30. But I don't anticipate problems with that.

Russell Brinsfield: Suspended solids can create a real problem. You can have water that appears to be clear but has essentially zero transmission.

Mr. Schieble: The main design parameter you are going to utilize for the UV is the UV absorbance characteristics of the waste water. You can have high absorbance particularly in an untreated waste water. Most of your absorbance comes - from your dissolved fraction, your dissolved contaminates. Turbidity has been found in fact at times to benefit UV, since it allows scattering of the UV energy, so it's not absorbed. It remains available within your water column.

Q: What is the optimum or which way does the temperature dependence of photo-reactivation go?

Mr. Scheible: At the higher temperatures, you will get a greater degree of photo-reactivation. In the summer months, we saw up to a log increase in effluent densities. In the winter months we saw anywhere from zero response up to maybe a .2 log increase. So I don't think you can speak of optimum conditions for photo-reactivation. You are talking about an environmental condition that you are going to have to handle.

Mr. LeBlanc: The control point for doses is five minutes. But between 15 to 30 minutes are actually required to obtain good disinfection. Five minutes is not adequate. You still have some residual after five minutes but the optimum control point for your dosage control is five minutes. I believe most systems which use bromine chloride have 30 minute contact tanks. Usually there is very little residual if any left at the end of 30 minutes.

Ms. Reeves: The Sanitary Commission has been operating an ultra-

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violet-light facility for perhaps more than four years. This plant which discharges at the Patuxent River has a design capacity of about 7% MGD and a flow of around 4% to^5 MGD. It s a plant that has a great deal of redundancy. It s a good secondary. It has not only the normal grit chamber for primary treatment, but it -also has trickling filters and activated sludge. Then a micro strainer with ultra-violet light. Then for the ultimate the chlorine contact chamber chlorinates the hell out of it. It is sent into the Patuxent River which at that point has a very low flow, because we dammed it just a couple of miles upstream. The water then flows through the Patuxent Wildlife Research Center which has the endangered species center. They would love to have that flow without the chlorine because of all the chloramines. ^ There is no water contact at any point and no use as drinking water. I have asked again and again, is there any information on the operation and maintenance cost and the economics pertaining to this ultra-violet light facility which has been operating in our area for all these years? Also, have we any adequate information on the effectiveness of the UV disinfection at that plant?

Mr. Alpert: The UV is not the primary disinfection device at the facility. It is used mainly to keep the micro strainer clean and avoid any growth on the strainer facility. Chlorination*is the primary disinfection process. There ^s no reason to believe that UV couldn't be considered in the next version of a facility plan.

Mr. Sawyer: The ultra-violet is simply to keep the microscreen surface clean by keeping the slime down. In testing their effluent over a period of a few weeks, we never found excessive chlorine residuals. They had very good control over the chlorine. - ,

Mr. Alpert: Would you define what you mean by excessive.

Mr. Sawyer: We never found a residual 3 parts per million and generally around 2 or less in two weeks of study. And we were taking grab samples each hour for about 8 hours during that study.

Q: Do you have any SO2 use costs?

Mr. Alpert: The range in cost that I have is for from a 1 to 100 gallon MGD facility. We go from use of gaseous chlorine at 3%C for 1000 gallons for a 1 MGD facility down to .7c/ thousand gallons for 100 MGD facility. When you combine the chlorine with sulphur dioxide the 3.5 rises to 4.5 and the .7 to .9, so we are talking about 15-20 percent increase.

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Will Baker: Why did you omit chlorine dioxide among the list of alternatives?

Dr. Burton: Probably because it's about 13 times more expensive than using chlorine.

Q: Where will the initiative come from for new innovations? Our engineering educational institutions and bureaucracy seem to dampen it.

Mr. Alpert: I worked for three state agencies in Maryland before going into the consulting business. The theory was, in the Maryland Health Department, chlorinate sewage effluent heavily because that's the only way you can be sure you are going to kill everything. The Water Resources Administration philosophy was, take the chlorine out of the effluent. We ended up with a protracted battle among agencies for years over chlorine. While that was happening, equipment manufacturers , consultants and communities alike got really alarmed in Maryland about the battle, so they started looking at alternatives. Unfortunately, there was very limited flexibility in approving designs. The institution responsible for issuing construction permits really did not feel confident that there was reliable information to substantiate that alternative systems could work. Now, I'm in the consulting engineering business, and the first thing we have to do is examine alternatives. I see progress throughout the regulatory realm at this point on standards and probability. Ozone, UV, and bromine are being looked at seriously. Five years ago they wanted to put in an ozone system in my county and the state would not approve it. Now they are going in with chlorine/dechlorination. If they were to propose ozone today, the system might be approved. I think there is growing flexibility. I'm getting a little sensitive to the feeling that engineers are trained in a very narrow fashion. One of the tenets of

^ engineering education is to examine all the alternatives, and it's always been come up with the least cost option. Only recently have we been turning around and trying to balance the environmental costs with actual total costs in a system.

Mr. Sawyer: I have been in engineering education, and, as you say, I am getting a little sensitive that engineers are blamed for all of our problems. Everybody should realize that politicians are responsible for all the problems!; They make the decisions, and the lawyers make the laws. Those decisions are how much money are we going to spend for this system and that system. Most of the money that should have been spent for utility system work wasn't spent. I know how EPA came up with their figures on how much money they are going to save, but most of the "innovative" projects

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that we have reviewed from a regulatory standpoint in Virginia haven't saved all that much money, because three- fourths of the cost of a utility system is under the ground in the pipes. These are the things that people will cut corners on. Sloppy construction causes most of our problems in sewage treatment today. Only twenty-five percent is in the treatment system itself. As far as land application is concerned, that's great for the great south- west United States. But when you are in the eastern state with poor quality land as in some of Maryland and most of Virginia, you've got either rock or high water tables, and land application is not really a serious available alternative. The reason why engineers and bureaucrats are not the ones to hop on some new solution is because we have been trained to evaluate all the factors. We don't consider just one aspect of the problem such as toxicity to marine life over the considerations for public health over the economics which have been posed by the political system. All of these things have to bevtaken into account and then the final decision is really supposed to be made by the public. Now, if you don't like the decision that's been made, I suggest that you elect somebody that makes better decisions next time.

Gerry Gallaher: I'm not in the habit of defending politicians, but I don't think politicians are always as badas they have just been painted, nor engineers as careful as the ideal presented either. On the EPA aspects of INA, in funding a plant that does involve innovative or alternative systems, only that part of the plant that can be considered innovative or alternative will get this extra funding. :

It's not the whole plant. Is that correct?

Mr. Wheeler: In some cases, if the innovative or alternative part of the system is a major portion, EPA will fund the entire plant. In other cases where we are talking about a specific process or unit process to replace a conventional process, we will only fund at the 857o level that particular unit process.

Q: How long does it take to get these requests through?

Mr. Wheeler: If you want to talk about a total project, from inception of the facility's planning to turning on the water, we've been averaging about 7 years. The INA program has only been in effect for three years and we've already funded 157 projects, so obviously the INA projects are not taking 7 years.

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Power Plants

Q: What organisms are the targets of power plant chlorination?

Mr. Guiland: At Chalk Point, the primary animal that we're concerned about is colonial hydroids. They grow rather rapidly with warm water into mats that foul the intake area.

Q: Would it be feasible to use a dual system...run one system one week and run the other the other week?

Mr. Guiland: There's nothing that prevents having a duplicate power plant. You must have two power plants. A condenser system is in fact the guts of the power plant. We are talking about 257o of that power plant, which may cost a billion dollars to be duplicated. At Calvert Cliffs they have the ability to fractionate the condenser system into parts, and they have the ability to go in, I think, to clean parts of the condenser bundle. We are discussing the condenser, not the intake conduit system, which must also be protected. We have mechanical alternatives for actually clearing the condenser tubes. The Amertop system pushes small balls through the condenser tubes to clear fouling. That is installed at Chalk Point and Morgantown, and works very effectively. The problem now is the intake counduit, and you can't have fifty-four inch balls to do that.

Q: Do you see any changes in your chlorine demand as a function of the raw ammonia that is available in the estuarine environment as well as in the biological form?

Mr. Guiland: Yes, we do. It is very difficult to control it, because you are not only dealing with organisms, but also in the estuarine environment and with poor water quality.

Q: At Chalk Point, do you see any correlation between the use of chlorine and identifiable events particularly storm , events and sewage treatment flows?

Mr. Guiland: There's been a lot of talk about the high nutrient level and phosphate level in the Patuxent River. We do not see that to be a significant issue, as something that fluctuates. However, we have seen major changes as a result of storm events. For example, because we had at Chalk Point at ah area where the estuary widens quickly, we find the intrusion of salt changes the salinity rather rapidly with the change from fresh water run-off. That change, therefore, will alter the chlorine demand. After a storm we have more detritus and, therefore, more chlorine demand. It is very costly to foul a power plant. If it happens at

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Chalk Point, it will take two years to clean the condenser bundles. It is going to cost approximately $200,000 of generating revenue in terms of power electricity you have to buy from some other utility. If we err, it is on the side of overchlorination, because of that cost.

Q. Could you clarify for us again the reasons for your state- ments that there aren't any alternatives to chlorination?

Mr. Guiland: I am talking specifically about proven alternatives that are in operation at a power plant. With the potential cost expenditures that might result from failure of those alternatives in terms of fouling, we cannot have the luxury to play around with any technology that is not yet proven. So when I'm talking about alternatives, I'm talking proven alternatives.

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CONFERENCE WORKSHOPS

The Workshops provided an opportunity for the participants to discuss the use of chlorine and its alternatives in an effort to develop management strategies and recommendations. Partici- pants elected to attend one of the five Workshops: three on sewage treatment plants (STP), one on power plants and one on food processing. The following people served as discussion leaders: Kathy Ellett, Sally Kanchuger, Suzanne Pogell, Merilyn Reeves, and Bill Wolinski. We thank these leaders for working with their groups in evaluating chlorine and its alternatives according to water quality impact, monetary cost, implementation feasibility, environmental effects, and resource and energy usage.

During discussion, participants reviewed conference pres- entations, related professional experience, and synthesized their ideas into recommended strategies for managers and decision-makers. These Workshops made the conference more than just a fact-finding venture; they outlined future action.

The recommendations of the Workshops follow:

STP Workshop #1 1. MAKE CHLORINE AS TROUBLE-FREE AS POSSIBLE; 2. GIVE PRIORITY TO HIGH QUALIFICATIONS FOR STP OPERATORS--

IMPORTANT NO MATTER WHAT THE ALTERNATIVE; 3. PERFORM IN-SITU EXPERIMENTS.

STP Workshop #2 T. USE THE TERM BACTERIA CONTROL RATHER THAN DISINFECTION; 2. MAKE A CASE BY CASE DETERMINATION OF THE NEED FOR DIS-

INFECTION; 3. MAKE A CASE BY CASE DETERMINATION OF THE ALTERNATIVES; 4. REVIEW MANAGEMENT AND CRITERIA TO IMPLEMENT RECOMMENDATIONS

2 & 3.

STP Workshop #3 1. RE-EVALUATE CRITERIA FOR DISINFECTION; 2. ADOPT CHLORINE OPTIMIZATION PROGRAM IN TERMS OF ADDRESSING:

a. SEASONAL APPLICATION b. MEETING STANDARDS WITH MINIMUM CHLORINATION c. REHABILITATION AND MAINTENANCE OF STP EQUIPMENT d. RE-EVALUATION OF STATE CONCENTRATIONS FOR TRC IN EFFLUENT e. ADEQUATE TRAINING OF AND SALARY LEVELS FOR OPERATORS

3. ESTABLISH A PRIORITY LIST OF PARTICULARLY SENSITIVE PLACED STPs BASED ON WATER USES AND DEVELOP A DATA BASE FOR ALTERNATIVES TO CHLORINATION;

4. CONSIDER COST EFFECTIVENESS IN ADDRESSING BOTH THE ACTUAL

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USE OF CHLORINE AND ITS EFFECT ON THE BIOTA OF RECEIVING WATERS;

5. RESEARCH THE SIGNIFICANCE OF TRIHALOMETHANES AND THEIR BIOLOGICAL SIGNIFICANCE;

6. COMMUNICATE THE ABOVE STRATEGIES TO EXISTING PUBLIC AND ADVISORY GROUPS.

Power Plant Workshop 1. POWER GENERATING PLANTS HAVE IN LARGE MEASURE COMPLIED WITH

THE REQUIREMENTS OF THE LAW; 2. CHLORINE AND ITS RESIDUAL COMPOUNDS ARE TOXIC AND, TO THE

EXTENT POSSIBLE, SHOULD BE MINIMIZED IN THE ENVIRONMENT. UTILITIES MUST CONTINUE TO EMPLOY CHLORINE MINIMIZATION STRATEGIES;

3. AT THIS TIME, THERE IS NO PRACTICABLE ALTERNATIVE TO CHLORINE FOR CONTROLLING BIOFOULING IN POWER PLANTS;

4. CONTINUE THE NECESSARY RESEARCH PROGRAMS TO FIND BETTER WAYS OF DEALING WITH CONTROL OF BIOFOULING AND ATTENDANT CHLORINE USE IN POWER PLANTS ON AN ESTUARINE SYSTEM.

Food Processing Workshop 1. INVESTIGATE PUBLIC HEALTH SIGNIFICANCE OF HIGH FECAL COLIFORM

LEVELS IN WASTE WATER DISCHARGES FROM SEAFOOD PROCESSING OPERATION TO ASSESS THE NEED FOR DISINFECTION;

2. ESTABLISH A COOPERATIVE PROGRAM BETWEEN THE FOOD PROCESSING INDUSTRY AND STATE POLLUTION CONTROL OFFICIALS TO PROVIDE THE TECHNICAL SUPPORT TO INSURE TIMELY AND ECONOMICAL COMPLIANCE WITH EFFLUENT LIMITS;

3. INVESTIGATE THE GROSS DISPARITY BETWEEN THE STATE OF MARY- LAND AND THE STATE OF VIRGINIA REGARDING WATER QUALITY STANDARDS FOR BACTERIA;

4. EXAMINE THE NEED FOR HIGH CONCENTRATION CHLORINE DOSAGE FOR EFFECTIVE DISINFECTION OF FOOD PROCESS EQUIPMENT AND WORK AREAS.

Page IflO

DISCUSSION OF MANAGEMENT STRATEGIES

David McGrath Chesapeake Bay Foundation

In this final session, we will hear from all seven of our panelists, who represent a broad spectrum of managers and citizens of the Bay; their specialties include legislation, the management of natural resources, water quality, wastewater treatment, and public health. They are representative of the people who will be most involved in making the decision that will form our management strategies for the future. They have heard the reports of the different workshops and are asked now to synthesize what they've heard and to develop some ideas on future strategies for wastewater management, and the management of disinfection, which may sometimes include no disinfection at all.

Calmet Sawyer Technical Services Chief

Bureau of Wastewater Engineering Virginia Department of Health

Let me start by reading a section out of a report on the effect of chlorine on oysters in the Warwick River by Bender, Haven and Slone from the Virginia Institute of Marine Science. This report was prepared in response to House Joint Resolution #162 to study the impact that the discharge from the James River sewage treatment plant was having on oyster set in the Warwick River prior to the confluence with the James. The effluent from that James River sewage treatment plant was implicated in the 1973-1974 fish kills in the James River; here is the conclusion. "From data available, which cover one complete oyster spawning season, no impacts on oyster set in the Warwick River due to chlorine releases from the James River Waste Treatment Plant were detected during the 1978 setting season." What they found is that the set below the discharge in the mouth of the Warwick River was the same per area as other control areas in the lower part of the James. It's information like this that has led the Virginia State Health Department as a regulatory agency to wonder if implicating chlorine as a very dangerous residual compound in receiving waters is warranted. We know that chlorine is toxic, and we know that overuse of chlorine and mismanagement of chlorine can cause problems. However, as Dr. Olivieri said, we don't

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see high residual chlorine out in these estuaries or in large receiving streams. So, how can we implicate it when we cannot detect it's there?

We are not saying that there should not be management of the chlorination process. We've always been in favor of proper management of wastewater disinfection, from a public health standpoint. There have been no documented outbreaks of waterborne diseases associated with the consumption of shellfish in the Chesapeake Bay area in recent times. Sometimes, maybe we are doing our job too well. There have been outbreaks in other places, which have been attributed to contamination in that water from sewage discharges of fecal matter. There have been none in our area--in the Virginia-Maryland area. And perhaps this leads us to the conclusion that disinfection is not necessary. But at one time, you could get typhoid swimming in these waters and, in fact, when I was raised in Newport News and Hampton, before we could go out swimming in Hampton Roads Bay we had to get a tetanus shot. It was required. I think that we may get ourselves into a position that we forget what useful benefits, from a public health standpoint, disinfection has accomplished. Saying that disinfection accomplishes no useful purpose whatsoever is just as wrong as saying there are no possible harmful effects from chlorine, because we can't see any harmful effects occurring. We would not say that and, of course, we certainly would not say that there is not a public health benefit from proper use of chlorine, because we know there is.

Evelyn Hailey Delegate

Virginia General Assembly

This has been a real learning experience. I think that one of the reasons that Virginia isn't more open to new suggestions may be that they have a saying in the General Assembly, "If it ain't broke, don't fix it." We labor under that saying all the time. But I have also found since I have been serving in the General Assembly, and I have reinforced here today, that water politics is very explosive politics. You certainly have an incompatibility here between politicians and engineers. You have a certain reaction between the two groups that may be harmful and could even have corrosive effects on a political career! I did understand one statement that was made by the gentleman from the EPA yesterday, Mr. Rubin. He said something about reclaiming valuable constituents. I understand that!

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One point I wish to make is that we have a communication problem, and this communication problem is evident throughout government. A lot has been said here today that I really didn't understand, but I'm trying to understand. I do understand that we have a problem with the use of chlorine, perhaps the overuse of chlorine. I was fascinated with the gentleman from London, but I also have the feeling that we live in different worlds and I, as a politician, would be uncomfortable taking that position.

One of the things that we see in the Virginia governmental system is a fragmentation of authority. Particularly when it comes to water. We have an ongoing thing between the Health Department and the State Water Control Board--Who is in charge? Recently it's been brought home in Hampton Roads. We have had up to 200 coal ships backed up. The citizens, particularly the innkeepers along the Virginia Beach strand, were getting very nervous about what was going to happen when the summer season came, and who was going to tell these ships that they couldn't do what they were doing. So, it didn't seem like anybody was coming forth to do something. I was beginning to get letters from irate constituents and, all of a sudden, Jim Douglas called a meeting. From then on, things started to take shape, and they did go and tell the ships what they couldn't do.

I think the point I come back to is communication. I think we need these kinds of meetings. I'm sorry that we don't have more Virginia politicians here, and I mean members of the General Assembly. One of the questions asked in the workshops was who do you tell about the feelings that we have and the things that we've learned here? I don't think that either Virginia or Maryland has a privy council, but it does seem that we might develop such a thing to take care of such questions. Thank you.

Catherine Riley Delegate

Maryland General Assembly

Evelyn was very kind. I have some remarks to make that are, perhaps, a little more pointed. In the last two days, I have heard more about chlorine than I ever wanted to hear. I've heard a lot about other things, too, over the years, but chlorine seems to be at the top of the list for the last couple of days. But, as was pointed out yesterday, I am one of those people who is paid to make the tough decisions. It's probably good that I

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am here to hear the conversations that we've had. I am here today as a member of the Maryland General Assembly, as a member of the House Environmental Matters Committee', and also on behalf of the bi-state Chesapeake Bay Commission--a commission which was created last year. The co-chairmen from each state were unable to be here, and I was asked to stand in in their place.

I had intended to talk about House Bill #570, the bill that prohibits the discharge of chlorine into trout waters. I think Secretary Coulter touched on that. I intended to answer any questions that you might have about that bill. However, the last 48 hours changed my mind, and I felt absolutely com- pelled to make some comments regarding this conference and the issue of chlorine.

I'm one who tends to believe that when you inject something into the environment, whether it's a synthetic or a natural kind of a chemical, if you inject more than was there before, there's a potential hazard. You are asking for trouble. You have to be very careful. It's true whether we talk about PCB's or herbicides or pesticides or acid mine drainage or chlorine or ozone. The Bay and all our water supplies are very fragile, although each can, up to a point, cleanse itself. But you reach a point where it cannot cleanse itself any longer, and that point is reached when there are more chemicals coming in than it can possibly get rid of. I personally believe that we've reached that point in the Chesapeake Bay. To me, the signs are very obvious: the fish kills, the loss of the shad, the loss of herring, the reduced white perch catch, the rock fish, the loss of grass. I represent Harford County-which is the uppermost county on the Western Shore bordering Pennsylvania, the Susquehanna River and the Chesapeake Bay. We have watched this happen over the last 10 years.

About two years ago, I had a conversation with Secretary Coulter. He was telling me about his concerns about chlorine. The only other people I had ever heard talk about chlorine-- the negative effects of chlorine--were the watermen. You know that people tend to discount watermen because they are not scientifically trained. They just use their heads. I listened very intently to what the secretary had to say, and it made great sense to me. I followed with interest the ban that was proposed then legislatively in 1980. I supported it and again supported the bill that was considered this year. The bill, in essence, bans the use of chlorine or chlorine compounds in the treatment of water that's going to be discharged into a Class 3 Trout Stream or its tributaries. The bill passed and was signed despite some opposition. But it made great sense to me when I talked to Secretary Coulter two years ago. It made sense to fight for that bill; it still makes sense to me today despite what I've heard for the last two days.

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During this conference, we have received a lot of information. A lot of it has been terribly scientific. I was reminded yesterday morning of my days in organic chemistry. I tried to remember what halogens were. But there was one rather non-scientific comment that was made, and the hair on the back of my neck stood up, and I made a comment. I was sitting up in that corner and, perhaps, what upset me more than the comment was the fact that it was received with a good deal of applause. I was taken aback by that. I am a politician, and Delegate Haley is a politician, and Delegate Winegrad is a politician, and those of us who are elected are politicians. I make no apologies for that, and I am, in fact, very proud of the work that I do. I am very proud of the work that the state of Maryland has accomplished in the environmental area over the last ten years. But it was suggested that such a scientifically "hot potato" as the use of chlorine should be dumped into the laps of the politicians because it is a policy decision. One of the things that I find very fascinating is that bureaucrats and scientists tend, when they don't want to make a decision, to say it's a policy decision, and it should be handed to the General Assembly. Time and again, those of us who fill those positions are confronted with making those tough decisions, and we have made them. We have made them at times with little or no help or little or no support from the so-called experts who supposedly know what they are talking about.

Now I might tell you that in the Maryland General Assembly that there are very few scientifically trained or scientifically oriented people. They are a handful. In the Congress, there are very few. We are dependent on the information that we get from those so-called experts. We rely on that information. In fact, we pay to get an awful lot of it. What we get back oftentimes is very much less than useful. There is an axiom that I learned early in my political career. That's been about 13 years. But I learned then, and it has held true for me up to this point, that when you find a scientist who will stand up and argue a position in front of a legislative committee, you will always find another one who will argue the other side. In fact, some members of my committee have asked the question, time and again, "Will we ever stop studying the Chesapeake Bay and get some answers?" I must say that the last two days have been interesting, and I think some of what I'm saying has been demonstrated here. I don't mean to step on toes, but I had mine stepped on and I thought that we ought to make some of these comments.

Let me say that I'm going to leave here with some questions that I would like to get answers to. Let me pose some of them to you.

What is the significance of the chlorine resistent pathogens mentioned yesterday? If the United Kingdom's method is wrong, or is not applicable to this country, why haven't they had sig-

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nificant outbreaks of shigellosis or typhoid? What's the meaning of the fact that Vibrio Cholerae exists in the Chesapeake Bay? How hard is it to study the Bay grasses? I have a report here that tells me that chlorine affects Bay grasses, and it's from the U.S. Fish and Wildlife people; they say it's absolutely a matter of fact that it's been proven. We've heard all kinds of things about that. There should be more information. Should one bathing experiment--a very interesting approach—be given so much credence? I was surprised at that. What are the bioaccumulation effects of chlorine on both fish and human beings? That's an important question. These are some of the thoughts I had, and some of the concerns I have. I'm really more confused now than I was when I came. Perhaps we are fortunate that there weren't more politicians here in the last few days.

But let me say this. I believe very firmly in what the 'state of Maryland is doing. I give my support, and he knows it, to Secretary Coulter for his efforts and to Assistant Secretary Eichbaum. I believe that EPA is moving in the proper direction towards flexibility, but I also believe that position is long overdue no matter what was said yesterday. One thing I will walk away believing until someone shows me differently is that as we, politicians, over the next several years will face these very difficult decisions, and will make them, the scientists will be still talking and wondering why we did what we did. Let me close by adding one other thing. I am by training a biologist; I spent a good deal of time doing both clinical and research bacteriology, and so I know some of the people very well of whom I speak. Thank you very much. It's been an enjoyable experience.

James B. Coulter Secretary, Department of Natural Resources

State of Maryland

It would be nice in situations like this if the clock could simply be turned back to before anyone took any kind of action; before there were any mind sets; before people became polarized in their thinking. We could approach the question of whether to chlorinate or not to chlorinate as an outright academic exercise. Unfortunately, we cannot.

We are here, however, to discuss management strategies.

To begin with, I find that my position on the matter is greatly misunderstood in the State of Maryland. People come

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to ine and say: Boss, it s decision time. Do you want to go left or do you want to go right?"

I usually tell them to go to hell. I'm not the kind of super intellect endowed with the powers of diety. In fairness to me, however, I put that "go to hell" in polite language I ask them to return to their desks, analyze the problem and then suggest some options for me. The reactions I receive often are much the same as the reactions Kathy has described as she tries to unscramble the testimony we present to her committee.

^ that the greatest contribution I make to the people of the State and the programs I direct is an attempt to for- mulate theiright question. Bill Cronin said it this afternoon;

**- you don t ask the right question, you're not going to get the right answers.

If we could turn back the clock, and approach the question-- is chlorine a bane or a benefit?—what set of questions would we ask?

Several years ago, when I started down or up this path there were four questions. I want to test the questions and answers and see if they apply today. I think they do.

If we could start all over and if no one had put the first drop of anything in sewage as yet, we could ask first, should we disinfect? I think we would follow that by asking: will chlorine or any other strong oxidizing agent disinfect sewage under procedures currently in use at a normal secondary sewage treatment plant?

After those two questions, we should ask: what are the risks and costs to people in the use of chlorine at sewage treatment plants?

Finally, we ask the most important question: what kind of secondary effect would result from putting chlorine into sewage? How would the environment be affected for any other beneficial organisms that are not the targets of the practice?

Again, we cannot stop the clock. We arrive at these situations long after people have committed much of their lives to certain answers and certain activities. It becomes difficult even to phrase the questions. Much of the talk you have heard here would be more akin to what you would hear from theologians who have been trained in certain seminaries and developed certain points of view. For any of them to change their point of view would be equivalent to recanting if not heresy.

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Nor is it possible to take the questions in the order in which I have just recited them. We can't start with the first-- should we disinfect? Rather, we start with the question: what in the world is going on? There are all kinds of aberrations. Fish runs are not occurring; hundreds of millions of dollars are being spent on sewage treatment plants; and, incidentally, anyone who thinks watermen are thrilled over that expenditure is not talking to the same people I talk to.

We start looking for causes and very quickly discover there is a combination of aberrations traceable to chlorine.

For example, we went through an exercise of asking why aquatic vegetation was disappearing from the Bay. We put it to a group of scientists and gave them many possible theories. The one that kept coming back was chlorine.

We did the same thing with the American shad. Why was it disappearing? Was it because the tributaries are blocked? If so, what are they blocked with? Are the blockages mechanical, structural, chemical? Again, chlorine was high on the list.

We looked at this puzzle. Why do striped bass come into the Chesapeake Bay, produce eggs in abundance only to see that the hatch from the eggs promptly dies? Again, as scientists examined this phenomenon a great number of possibilities for its occurrence emerged, but chlorine was one of them.

Then came this question: Does the addition of chlorine to sewage at treatment plants harm aquatic plants and animals and beneficial microbes that are not the target of the attack?

The answer is clear. Chlorine is not selective; it is a powerful biocide. The same agents that foul up intakes at power plants are the same group of animals we talk about when we say that an oyster takes a set or a strike. It is a fouling organism. This is a very, very powerful material with which we are working. That is why it is used. If not used properly, however, it disrupts the beneficial things it contacts as well as it disrupts the targets. The conclusion of these examinations and exercises was that chlorine is a killer and we are using it promiscuously. We are using it promiscuously to the point that many beneficial natural life patterns that we see on the stream are being disrupted.

We moved to this question: What are the risks and costs to people? To begin with, we found that the use of chlorine consumed a tremendous amount of energy. It is a transportation hazard. One of the most common hazardous susbtances involved in transportation accidents is chlorine. Also, it was determined to be an occupational hazard. Many studies dealing with sewage treatment plant operators disclosed that their safety and health

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were threatened more by chlorine and the handling of it than by the very sewage processed at the plant.

Along economic lines, we discovered in these days of tight dollars application of chlorine to sewage is costing something like $310 a ton. In Maryland, that amounts to more than $4 million a year.

Still working backwards, we addressed this question: can chlorine or any other oxidizing chemical disinfect conventional secondary treatment plant effluent? To answer that adequately, you really have to ask another question: what is disinfection? I've heard the term used very loosely. I've challenged it and received this reply: "Well, we really don't mean that."

Let's turn to a companion field, water supply works. There, we really set out to disinfect, and we find that people discover it necessary to define disinfection. It is used to describe a process that removes all organisms capable of producing a disease. Disinfected water is not necessarily sterilized which, by definition, means that all forms of life have been destroyed. Such rigorous treatment of drinking water is neither necessary nor practical. Disinfection to most practicing sanitary engineers and most of the educated people in the field means that all forms of organisms capable of producing a disease are killed. Now, I'm trying to get to something more than a definition. We find that drinking water treatment plants use disinfection as the primary objective. On the other hand, wastewater treatment plants are not designed for disinfection. Chlorine is added to wastewater treatment plant operations to meet a numerical bacteriological standard of a rather dubious origin. It is absolutely wrong to think that either the engineers or the operators set out to disinfect the sewage. If they did, they would construct those wastewater works in the same patters, in the same mode and with the same unit processes used in drinking water supply plants.

If we believe our companion knowledge in the water purification field, we cannot disinfect sewage with the plants that have been built.

At this point, more questions are raised: should we re- design and reconstruct the plants and retrain the operators? Should we look for an alternative to chlorine.

Here, it seems to me, it becomes extremely important to address this question: do you really need to disinfect sewage in the first place? Should it be required? Again, that leads to a question: is there a history concluding that a significant number of people will become ill if sewage effluent is not disinfected?

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The danger points immediately emerge. We have heard three of them. There is a fourth: It is ingestion, the drinking or gulping of waters, raw waters which have been contaminated with treated or untreated sewage. Certainly, the eating of raw shellfish contaminated by sewage is one of the danger points. Swimming areas have received much attention and public water supply intake is another that has to be considered.

Just ask this question: is there reason to believe that sewage has caused a problem. Of course, you can say "yes" on number one. Anybody who has taken a good healthy swig of sewage probably will come down with infectious hepatitis or something else. Certainly, yes on number two; we know from our own experiences that people came down with many cases of shellfish poisoning before the interstate shellfish sanitation program began in the late 1920s. Since then, Chesapeake Bay has been free of any disease attributed to an approved shellfish harvesting area. The principal method used to achieve that end has been separation of sewage and food; in this case, the raw shellfish.

On swimming, the jury is still out. We've heard good evidence that people who swim in polluted waters and open their mouths are more liable to become sick than if they did not. I'll point out, however, that there is some very good epidemiological data to show that the same thing happens in swimming pools that are artificially built and chlorinated; facilities that have no contact whatsoever with any deliberate discharge of sewage.

On question number four, the case of water works intakes, it is debatable. There are data on each side. I believe beyond a shadow of a doubt that if the water works operator owned both installations, he would locate the sewage treatment plant somewhere else. Also, if he had some extra money, he probably would spend it on the water purification works rather than the outfall.

In conclusion, you really can say some positive yesses and some ifs exist. The answer is "yes", you can experience trouble with sewage at those danger points, but that does not mean the use of chlorine to combat the trouble is indicated. In fact, it might be extremely dangerous to trust chlorine which is simply used to lower the bacteriological standards to any kind of degree of protection despite the use of a multi- barrier system.

In my examination of this matter, I went beyond our shore. We'ver heard from Mr. Gamett's experience in the United Kingdom. I've heard some remarks that it might be different in the United States than in the United Kingdom. People over there don't like to swim with their mouths open. I think there's

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another explanation that should be brought out. Maybe it's different in the United Kingdom because the British, unlike citizens of the United States, cannot afford to spend money to do the wrong thing. We have to consider that as a possibility for the difference between us.

I went to Europe and, through the World Health Organization and other friends, asked what was going on there. They pointed out that they do not treat their sewage, but under pressure from something called EEC they are going to study the matter again and determine if they do need to adopt chlorination of their sewage.

I went to the Pan American Health Organization and received a rather trite reply saying they don't treat sewage with chlorine. In fact, they said they haven't built many sewage treatment plants. At first, you misunderstand that answer. They have real health problems. People are dying. They are putting their pesos into good water systems that deliver drinking water to their homes. If they have funds left over, they will build some sewage treatment plants. If they become^ as rich as the United States, they will think about chlorination. That's about the size of their response.

I turned to the American experience. I received com- munications from people like Joe Loheler, head of Camp, Dresser, McKee. He said: "The latest bunch of clippings contain several articles describing your controversial stand on the^ chlorination of sewage effluent. Stick to your guns. I think you are right. I have thought for many years about the horrendous waste of money in this country on the chlorination of sewage effluent."

I saw the General Accounting Office report in which the principal public health agency in the nation responsible for control of communicable disease said unequivocally that there was little public health benefit to be achieved from chlorinating secondary sewage treatment plant effluent.

I have read GAO reports before and I have known at times that they have been incorrect in their quotations and the identity of the persons they attributed them to. Because of that, I telephoned the Assistant Surgeon General in charge of sanitary engineering matters and asked him if the GAO quotation was accurate and if the statement represented the position of the United States Public Health Service. I was told that it was. Furthermore, I was given the name of a gentleman in the Communicable Disease Center in Atlanta. His name is G.F. Mallison. I wrote and received a reply stating that the Communicable Disease Center believes that, in the general case of secondary effluents, chlorination is a waste of money and very little public health benefit can be ascribed to

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disinfection of sewage.

I reached a conclusion and it is a stragegy really. In general, with few exceptions, disinfection is not needed. If it were needed, we would have to invent a sewage treatment plant designed and operated to accomplish disinfection. Simply adding chlorine or any other alternative substance to sewage treatment plants as presently built, with or without baffles, with or without retention times, is not going to give you disinfection until you obtain the same degree of clarity, the same control of pH, the same elimination of interferring substances, the same conditions that we know work in water purification plants. So, if we need disinfection, we must change sewage treatment plants altogether.

Now, let's be practical. There is a Federal law mandating water quality standards. A water quality standard has a bacteriological requirement. We cannot meet that requirement without some kind of killing agent introduced into the sewage. It seems to me that no matter what I think or what my conclusions are, we are going to be adding chlorine to many of our sewage treatment plants until either I'm proven wrong or the while world comes around.

I think that my Federal Government should take a uniform stand on the matter. I see the Environmental Protection Agency saying there is a health hazard. I see the Surgeon General who's known for issuing public health warnings at the drop of a hat saying in this case there is no public health hazard. I'll think I will do the best I can in my office to bring the two of them together and see exactly what the Federal Govern- ment is going to do on the issue.

Meanwhile, in Maryland, our strategy, working closely with the Department of Health and Mental Hygiene, is to go to every sewage treatment plant in the tributaries of Chesapeake Bay. Please understand that my analysis has taken me to the tributaries , not the Bay proper where bromides and all that other material occurs. The problems occur in the tributaries where the fish come to spawn and where many vital biological processes take place. Between the Department of Health and Mental Hygiene and the Department of Natural Resources plus the utmost cooperation from individual sewage treatment plants, the strategy will be to stop the use of chlorine during those periods of time when the public health can stand the risk. In all other situations, we will cut the use of chlorine as far back as possible. Certainly, I am not pushing for any alternative to chlorine that will just move from one oxidant to another until these basic issues I have mentioned, these basic issues of whether you need the stuff in the first place, are settled.

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^ Cranston Morgan Chesapeake Bay Seafood Industry

On behalf of Hugh Garnett I've got to take exception to something Secretary Coulter said and that was that Great Britain doesn't spend its money on wrong things. They have done a couple of wrong things, I also would like, if I'm not a traitor to my industry, to talk about shellfish. We heard a food and drug man yesterday talk about all the shellfish problems. I was more than delighted to hear Cal say that there had not been any diseases on the Chesapeake Bay since our National Shellfish Sanitation Program started. I would like to add to that there have been very few cases of any viral diseases in oysters anywhere. We had 500 cases at Raritan when tourists from New Jersey violated the closed area by picking up clams in an illegal area. We saw the importation of South American oysters that were accused of being oysters from the Gulf. There were around four or five hundred cases of hepatitis. This was many years ago, and we have not had any outbreaks along that line, before or since. So I would assure you that you can, anywhere on the Bay, eat shellfish raw, cooked, or otherwise. I might say that I prepare them in any fashion that you could use them--a little commercial! I was delighted to hear the Honorable Catherine Riley state her opinion. You know politicians don't often lay it on the line like that and of course, we are not going to cast many votes for or against her, so I guess she didn't mind. However, she said many things that I had intended to say.

I'm going to tell you a joke, expressing Catherine's and my condition after listening to this workshop. I have completed another workshop on religion and Christianity, and I left that equally confused so, don't feel convicted on that! This fellow went into the station in New York and asked for a ticket to Rosedale. "Can't sell you no ticket to Rose- dale. Train doesn't stop in Rosedale on Friday nights". I said, "Well I've got to have a ticket. I'm desperate. This is life or death." So the ticket master said, "Well, tell you what you do. I'll sell you a ticket. You go aboard the train and talk to the conductor and maybe, just maybe, you can get the engineer to slow down going through Rosedale so you can get off." Sure enough when they got near Rosedale, he could hear it slowing down and just as he got to the slowest point, the engineer shot the steam to the engine, and he jumped off. There he was, his feet propelling as fast as he could go to try to keep up with his body. This gentleman on the next car saw him, and he went out on the platform and reached out and grabbed him by the collar and dragged him. on the train! He said, "Man you don't know how

/

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lucky you are, don't you know this train doesn't stop in Rosedale on Friday nights?" So that is about my condition after being exposed to two days of chlorine!

We need to take a fresh look at what we're doing to our environment. You see, I am one of the recipients and bene- factors who receive the benefit from these programs, and here are the benefits I have received. In Virginia, we were getting three to five million bushels of oysters per year, and I liked this because I did have a little bit of profit. We could get a proper amount of product and a proper product to sell to the consuming public. The state of Maryland was up to two to five million bushels a year, and we had a great availability of oysters in the Chesapeake Bay. Our major concern was whether or not we had a product that would be fat and delectable enough so the buyers would buy it. Today we get anything that we can, and we are still going down.

In 1979, instead of three to five million bushels, the state of Virginia produced only 600,000 bushels. As a result, we have had to import our oysters from Maryland. Incidentally, I believe Maryland is doing a great deal for the environment and has a greater consideration of the environment than do we in Virginia. I say this with my friend Mike Bellanca here along side of me. I think the political arena in Maryland is more aware and receptive to proposals along that line than we are. However, we do have two bi-state agencies, and I'm hopeful that these will make inroads in these differences.

I have an article here by Richard Storms in Outdoor Life entitled "Chlorine, the Hidden Killer". It says, lurking largely unseen by American outdoorsmen is one of the most shocking, ecological crimes of our times. The systematic killing of millions of gamefish by public health authorities under the guise of wastewater disinfection. Among all the disgraceful insults we heap on our fish, chlorine is one of the worst. This fish killer even gets enormous public support as it goes about its deadly work under the false colors of a cleanser of water." Now, as a layman, I have very little knowledge of the total effects of chlorine. I would suggest that we are looking at the picture of chlorine with a very myoptic view. We look at sanitary engineers who have to have clean water or it's a public health hazard. We, in other fields, are saying, "what's being done to me?" I think we are doing very little looking at the total problem. I don't know the merits of not chlorinating as they're doing in Britain. I do know that they are producing fish in greater quantities. I do know they are producing oysters, and I do know that we have had an improper amount of chlorine going into our streams. From an economic standpoint alone, I

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think we need to consider, as Merilyn said, case by case discharges. You know, the chemical people are doing very well. We are operating a foundation by Allied Chemical in the state of Virginia, and I suspect that if they have to curtail their chlorine production, they will probably survive. So I think that all efforts should be made to have minimal discharge at the outfall.

I would like to make one other point, and I think that would be all that I would like to commit myself on. Dr. Bender did make the test on chlorine. He came up with astronomical amounts of chlorine in the lower James. He did it on a $25,000 study for the State Water Control Board. Now, to go on further, the Virginia Marine Resources Commission made a great effort in talking to Drs. LeBlanc and Wheeler and whoever else to try to get the Hampton Roads Sanitation District to curtail their chlorine discharge during our spawning season, August and September. They did this on their four treatment plants. Their fifth treatment plant is the Williamsburg Treatment plant which has Anheuser Busch that has been operating on a temporary permit ever since their construction. So they didn't cut down on their chlorine there. However, we saw an immediate strike of oysters in that lower area of the James a good strike we have been using for the last three years. This year we've seen a great decrease in the amount of fresh water coming from Susquehanna and all of our rivers. Our goodies coming down the river didn't come down. So we've got a good strike. This is not scientific, but it's a fact.

I feel that the curtailment of chlorine will be good in many ways. I think we are being exposed to chlorinated hydrocarbons. The enemy is chlorine combination. Very little has been said here today about what happens when hydrocarbons are bombarded just before they go in the outfall. We are getting hundreds and hundreds of chlorine combinants that are unnamed and unheard of, and I'll prove that. We had a thing called Kepone in the James River. To test for Kepone, we had to screen 40 parts per million of chlorine combination in the gas chromatograph columns. We, in the oyster industry, were not worried about kepone, we were worried about the 40 parts per million. We are still worried about it.

I'm delighted that we finally got all of these things out in the'open. I've been seeking this for several years, and we tried to get such a forum for the Citizens Program. I think that it has been beneficial. I think it has brought people together. I think we've shared differences of opinions, and I think we are going forth from here, thinking in terms of what we can do to curtail chlorine, whether we are politicians, sanitary engineers, environmental experts, or control agency people. We also had one thing going for us

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now in the field of economics. In the next four years, we'll see many things curtailed, and many funds deducted from the scientific world, from agencies, and from all of us. I've been one of those spenders and recipients of funds for many years, and I've been one of the special interest groups that have caused politicians to spend us a trillion dollars in debt. I think it is monstrous that people representing the people of the United States should spend in that manner, and I was part of it. I regret that part of it. And, what I think is equally monstrous is for people to let a situation that scientists believe is harmful to our marine life to continue. I know that all of us are going to participate in doing better.

I hope I'm not offending anybody. Personally, I'm a Christian and the second thing I am is a friend of anybody who would be, and the third thing is I like to be happy rather than too serious. So, forgive me if I have offended anybody, but this is my feeling on the subject.

William M. Eichbaum Mary Jo Garreis

Office of Environmental Programs Maryland Department of Health

and Mental Hygiene Baltimore, Maryland 21201

Disinfection of wastewater has been a valuable tool of public health agencies. Any management practice concerning the disinfection of wastewater should be based on both the immediate need to protect public health and the environmental impact of the residuals of the disinfection process.

The controversy surrounding the use of chlorine involves two separate issues which have become synonymous in the public's mind: the public health necessity for disinfection; and the use of chlorine as a disinfectant. The recent controversy over sewage effluent disinfection arises from the scientific community's increasing concern about the toxic effects of chlorine on aquatic fauna, particularly fish. Since chlorine has been the traditional and most widely used sewage disinfectant in the United States, the terms "disinfection of sewage" and "chlorinate" have become synonymous. A good strategy for managing wastewater disinfection must address and evaluate each of these issues, and synthesize the evaluations into a comprehensive approach that protects both the public health and the environment.

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The current policy of the Maryland Department of Health and Mental Hygiene is to require disinfection at all sewage treatment plants and at some industrial plants. Disinfection of sewage wastes is based on the public health practice of containing disease at its source. Contact with human waste has long been recognized as one of the primary modes of spread- ing disease. Disinfection of treated sewage effluent reduces the number of disease producing organisms entering the environment. Subsequently, the chance of human contact with waterbourne pathogens through water contact recreation, shellfish consumption, drinking water or the environment is minimized.

In developing a good management strategy, we must first address the question of the need to continue disinfecting sewage wastes. Toward this end, we have initiated an evaluation of our disinfection policy. We are evaluating the historical development of disinfection practices and assessing the available medical and public health evidence supporting disinfection. When

this review is complete, we will decide whether to continue our present policy of requiring disinfection at all sewage discharge points or to require it only at certain locations.

Once we determine where disinfection is needed, our . management strategy must address the type of disinfectant to be used and its environmental consequences. The four most widely used methods of disinfecting sewage are chlorination, application of bromine chloride, ultra-violet radiation and ozonation, with chlorination being the most popular.

The continued use of chlorine as a disinfectant is a viable alternative. Where chlorine is in use or proposed for use, environmental assessment will determine if dechlorination is required. The first step toward reducing the discharge of chlorine to the environment is the improvement of existing chlorination facilities. This can be accomplished by good initial mixing, better on line.chemical feed, better contact chamber design and more accurate residual monitoring. For instance, in the final stages of a program tagged Operation DO-IT, forty sewage treatment plants have been visited by a special team which concentrated on improving the performance of chlorination facilities while reducing chlorine discharges to tributaries of the Chesapeake Bay. Preliminary evaluation of the program indicates that in several cases we were successful in reducing the chlorine discharged to the Bay by making minor modifications, such as relocating chlorine diffusers, improving mixing or installing baffles. The techniques we learn from this project will be extended to other treatment plants through our regional engineers.

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Another approach to reducing the amount of chlorine discharged to the environment is to encourage good facility planning. Through the 201 facility planning process, the designers of new plants can be encouraged to: (1) use land disposal and avoid overboard discharge; (2) optimize the design of chlorination facilities to reduce the final total residual chlorine (TRC); (3) incorporate dechlorination facilities as part of the plant design; or (4) select an alternative disinfection method such as bromine chloride, ultraviolet radiation or ozonization. In one new plant now on line, Sod Run, improved design of the chlorination facilities is resulting in a discharge of .05ppm TRC to the environment without dechlorination. At a second new plant, Mattawoman sewage treatment plant, the total residual chlorine leaving the chlorine contact chamber is 0.6ppm or less. Levels actually discharged to the river 3800 feet away are reduced still further. Good planning and design can make a difference.

We are gaining experience with alternatives to chlorine. We now have two sewage plants using bromine chloride and a third

plant has petitioned the State to use this disinfectant. In the third plant, we will monitor the receiving stream to see if the species diversity and general ecology improves when the plant changes to bromine chloride. Information from this study will be used to evaluate the place of bromine chloride in our total management strategy.

Ultraviolet light has been used successfully at a number of small treatment plants in Maryland. Unfortunately, little is known about its application at large treatment plants handling millions of gallons of wastes. Ultraviolet treatment requires high quality effluent which is not always available at all sewage treatment plants.

Ozone appears to be an effective alternative to chlorine. It is a good viricide and contributes to a well-oxygenated effluent. There -ire still, ^"over, some unanswered questions concerning its ultimate effect on the environment. The Potomac Heights sewage treatment plant was the first plant to try ozonization in Maryland. This secondary sewage treatment plant experienced difficulty with its ozone operation and has since abandoned ozone for traditional chlorine disinfection followed by dechlorination. We will try ozonization again at the Ocean City sewage treatment plant where it is anticipated that improved design will enhance operation.

In addition to the planning process, another way to encourage the use of alternative disinfectants is to ban the use of chlorine at specific locations. For instance, the Maryland Legislature recently passed a law prohibiting the use of chlorine or chlorine compounds, including bromine chloride or

Page 198

chlorine dioxide, in treated wastewaters discharged to natural trout streams. As the affected sewage treatment plants switch from chlorine to other disinfectants, such as ultraviolet radiation, two or three plants will be selected for in-depth study of the changes' impact on the receiving streams' ecology. Again, this scientific information will be used to refine our management strategies.

Another management approach to reducing chlorine discharge is seasonal disinfection. Effluents discharged to recreational waters may require disinfection only during the recreational season. This approach requires careful public health evaluation and we are investigating reports that seasonal disinfection is used in other States.

Incorporating all of these alternative approaches into a good management stragegy will require careful reflection. To ensure uniformity and promotion of both public health objectives and environmental concerns, a decision tree must be developed which will incorporate all alternatives but will allow their

application on a case-by-case basis. There will be no simple solution which can be applied in all cases. Each case will require a decision first about whether disinfection is necessary, and if so, then about the best alternative or approach to use. Through a well-developed management strategy that recognizes all options, including the continued controlled use of chlorine, we hope to bring sufficient flexibility to the management of chlorine to allow its continued use while reducing its environmental impact.

The Maryland Department of Health and Mental Hygiene is actively working to reduce chlorinated discharges to the environment. Through both Operation DO-IT, our field inspection program, and Operation Tide, a program to install temporary dechlorination facilities for the critical fish spawning season, we are achieving this

The environment receives stress from a number of sources and chlorinated discharges may contribute to this stress. The reduction or elimination of chlorinated discharges will probably have a demonstrable effect in very few situations. Through a good chlorine management stragegy, the best result we can hope to obtain is a reduction in stress on the environment, not a panacea for declining fish populations, poor oyster catches or any one of a number of environmental problems.

Page 199

Michael J. Bellanca Deputy Executive Secretary

Virginia State Water Control Board

A conference such as this gives us an opportunity to crystalize ideas and to meet other people who have different points of view. Before I can really address a problem, I have to understand where other people are coming from--to put myself in your shoes, so to speak, and understand your feelings. I still get the impression that we are wedded to those same pros and cons relative to chlorine and the issue of disinfection that we came with. Certainly we are not ready to abandon them. I know that in Virginia we have approximately 1200 municipal permits. I dare say that every single one of them, save about four or five, are using chlorine as the mode of disinfection. Simply to turn over to a new system is virtually impossible at this point.

Chlorine is a toxicant, it's a powerful one. Otherwise, it would not have been used with the frequency, with the completeness, that it has been over the last several decades. But I think that common sense tells us that we may have a problem. It is a toxicant and, because of its powerful nature, we have to be aware that there may be some adverse environmental problems. Because of my involvement with the fish kills in the James River in '73 and '74, I may have to bear some of the onus for crystalizing this problem. However, I don't think that we are in any position to abandon circumstantial evidence simply because we don't have the scientific data with which to back up the position that was taken then, and which I'm not ready to abandon at this point. We are, however, ready to listen to anybody else that has a position and data as well.

The systems that we are trying to protect are multi-use systems, managed on the basis of our standards: a standard for shellfish, a standard for fisheries, a standard for swimming. We have a different system from the Europeans. But we have not allowed our uses to float, so to speak, to the point where we optimize them. It may very well be that setting a standard which is the most conservative does not enable us to husband or to utilize our resources to the maximum extent possible--optimization of the resources and their propagation.

Let's take the fish and shellfish. Their productivity is enhanced or inhibited by natural variations, such as salinity and turbidity. They are also inhibited perhaps by the chlorine discharges. Now, our aim should be to optimize the system and, in doing so, we may, of necessity, gravitate

Page 200

in certain areas to singular use systems. I don't think we should be afraid to address that. Perhaps the multiple-use concept that we have in this country, and upon which our standards are based, is wrong in certain areas. I wouldn't abandon it completely. We may find that disinfection, as we call it today, is necessary in some systems, but totally unnecessary in others.

To really address the problem, each of us who had a preconceived notion when we came in here has to step back and try to look at the question from a little different perspective. Try to prove the other person right, so to speak. Try to prove yourself wrong. To view the problem in another manner--and associated with this there is a risk. Not just the risk to our public health, but the risk to our own egos. We have to be prepared to go out and obtain additional information, knowing full well that it is going to cost us a little bit. It cost me a little bit personally in terms of what my previous positions may have been. But if we are truly interested in the public at large and at getting the "best bang for our buck", that's what our responsibility is, that's what it leads us to.

We'll never have complete information. The scientists will tell you that. Oftentimes the regulatory people and the politicians, those who have to make the hard and difficult decisions, have to make these decisions with less than complete information. Sometimes it's simply the circumstances surrounding a particular issue which require that we make a decision. We will not always have the best, the most complete information available. So you have to do some by gosh and by dam. I think we have to be equal to that task.

Another thing that we have to address is that we cannot duplicate the environment completely in the laboratory. We do our environmental tests in the laboratory as best we possibly can and then we apply scale factors up or down. We have streams in which we apply one set of criteria to one discharge, and another set to another and we vary concentrations. We vary them seasonally in the other so that we can begin to focus on the issues which we have all addressed here today. The issue is simply uncertainty because of the fact that we are dealing with an overwhelming public health consideration. We may be paralyzed to the point where we will not budge off acceptance of a total conservative aspect. That's the thing that I'm very fearful of. When we make these changes, with the parallel treatment studies, we know that we are going to assume some risks. But these risks can be closely monitored.

Several years ago within a year after all the furor over kepone in the lower James River, the state of Virginia

Page 201

was faced with some major dredging in the five shoals between Hampton Roads and the Port of Richmond. We were told by the federal agencies that there would be absolutely no dredging because of the fear that we would resuspend sediments and we would increase kepone uptake, etc., etc., etc., and exacerbate an already bad situation. We took this issue to Washington, we sat around the table with EPA, Fish and Wildlife, National Marine Fisheries, and the Corps of Engineers and we said, "Gentlemen, if we continue to take that sort of a posture, then when we have to come back before you next year looking for permits, and the year after and the year after, all you will be able to say to us is that we have no data. We have no information; therefore, we can't grant you the permits." And we said, "Gentlemen, if that is going to be your posture, it's totally unworkable. Here is a solution. Allow us one project, closely monitored, and let's see how the environment actually responds to those changes, those artificial changes we make by resuspension of materials." We had the project and we found that the species did take up the kepone a bit more rapidly then they would have under natural circumstances. But they reached the same equilibrium level. Consequently, as a result of that type of an experiment, in which they had to have the guts of their own convictions to put something out, to put their necks out on the block, we were able to move forward with other projects. Like the turtle, we don't make any progress unless we put our head out. All the rhetoric not withstanding, we have to put our necks out just a little bit so that 10 years from now we don't come back to another conference entitled "Chlorine--Bane or Benefit" and sit here regur- gitating the same things we've said today.

With respect to politics, said to be the art of the possible, we won't obtain anything but the impossible unless we get off our duffs, stick our necks out and give the people who have to make the decisions the information by which to make them.

Page 202

CLOSING COMMENTS

L. Eugene Cronin Conference Chairman

The purposes of the Conference were

1. To focus attention on the impacts of introducing chlorine into the estuarine environment.

2. To provide guidance for the optimal protection of both human health and welfare and the Chesapeake Bay ecosystem.

These have been achieved. An excellent group of speakers presented expert comment ranging from technical chemistry and biology to politics and public policy. The possible detrimental effects have been stated, the present values of using chlorine have been explained, the alternatives have been presented and evaluated and responsible officials have clarified the reasons for their present positions and actions. Everyone who came knows more than they did prior to the Conference.

The roles of several essential elements in reaching decision on chlorine use have been clarified. They seem to be:

The scientific community must clarify knowledge of what happens if chlorine or other materials are introduced into the estuarine environment and predict the consequences of various alternative actions with useful accuracy. There is now much good scientific information, and it must be fully utilized in reaching decisions. There is also urgent need for more of the right kinds of science, including (1) clearer pre- dictions of effects on biota and human health, (2) research in the Bay to permit useful transfer of laboratory data, (3) critical evaluation of present criteria for the release of chlorine or its derivatives in the estuary, and (4) improved monitoring to detect and evaluate danger signals in the waters of the Bay and its tributaries.

National political systems must assist in setting minimum levels of practice, lead the development of decisions on the level of risk the public will accept, decide the roles of federal agencies, and provide part of the funds.

Page 203

State political systems, expecially legislatures, must select the laws which govern chlorine use, exert or delegate authority to establish regulations, and state the policies which represent the wishes and best interests of the citizenry. They must also make the increasingly difficult decisions on the allocations of limited funds for the wisest possible programs of construction and operation of the expensive systems for treatment of wastes as well as for research and enforcement.

State and federal agencies must develop detailed regulations, enforce these regulations, explore alternatives, and recommend to the legislative bodies. The states will apparently have an increasing responsibility as the federal government backs away from regulation and funding.

Local governments operate treatment facilities and must provide part of the funding for them. Here rests much of the control of the quality of operation of chlorination systems.

Industry is responsible for operation of chlorine-using facilities and for some of the research on improved procedures.

There, is an important task for each of these groups and for the citizens who observe, stimulate, and pay all of the bills.

There have indeed been serious declines and losses to the biological system of some parts of the Bay, especially near the metropolitan centers. The causes cannot all be assigned unequivocally. It is clear that waiting for quantitative answers has serious dangers. It would seem that the general consensus of this Conference has been:

• Improve the operational management of chlorination processes and equipment so that excessive quantities are,never released by accident, ignorance or intent.

• Limit the application of chlorine to the minimum rate necessary to protect public health.

• Investigate the possibility of reducing chlorine use at certain times of the year in order to minimize adverse effects on the reproductive cycles of fish

Page 204

and shellfish.

Improve analytic methods to identify and quantify the chemical materials resulting from chlorination and other treatments.

Continue use of chlorine for fouling control under rigorous operational restrictions when no alternative is available.

Speed research, especially field research, on the chemistry and biological effects of chlorine, derivatives of chlorine use and alternative treatment as they relate to estuaries.

Aggressively explore, develop and apply alternative biocidal techniques, including ozonation, ultraviolet radiation, and the use of bromine when they provide environmental protection within feasible economic constraints.

Assure the flow of reliable, understandable and relevant information about biocides to management agencies, legislators, users and the public.

Continue, as in this Conference, to consider the total Bay system as a single entity so that down-stream effects are taken into account and management efforts can be fair to all of the persons involved.

Page 205

CHLORINE CONFERENCE REGISTRANTS

MAY 27 & 28, 1981

MARY WASHINGTON COLLEGE

FREDERICKSBURG, VIRGINIA

Mark Alpert Metcalf and Eddy 11120 New Hampshire Ave. Suite 403 Silver Spring, MD 20904

Paul Ander City of Baltimore Back River WWTP 8201 Eastern Blvd. Baltimore, MD 21224

William L. Baer Rappahannock Area Develop.

Comm. 903 Princess Anne Street Fredericksburg, VA 22401

Fairfield S. Bain Rt. 1, Box 361 Wakefield, VA 23888

Robert J. Baker Wallace & Tiernan Div. PENNWALT Corp. 25 Main St. Belleville, NJ 07109

William C. Baker Assistant Director Chesapeake Bay Foundation 162 Prince George St. Annapolis, MD 21401

Debra Bames-Ashburn VA Water Control Board P.O. Box 669 Kilmarnock, VA 22482

Dane S. Bauer MD Water Management Admin. 201 West Preston St. Baltimore, KD 21201

Elizabeth Bauereis BG&E Charles Center Baltimore, MD 21201

Michael Bellanca VA Water Control Board P.O. Box 11143 Richmond, VA 23230

Gus Berlitz ASMFC P.O. Box 105 Deale, MD 20751

Larry Bowlby Citizens Program for Chesapeake Bay Citizens Steering Comm. Courthouse Prince Frederick, MD 20678

Steven Bradshal

Mary Brady Conference Organizer 10404 Edgewood Avenue Silver Spring, MD 20901

Robert H. Brands US Food and;Drug Admin. 900 Madison Ave. Baltimore, MD 21201

Linda L. Breisch Univ. of MD Sea Grant Prog. H.J. Patterson Hall, 1224 College Park, MD 20742

Russell B. Brinsfield Univ. of MD Dept. of Agri. Engin. P.O. Box 775 Cambridge, MD 21613

Page 206

Chlorine Conference Registrants (Continued)

William Bullard

Bruce E. Burns Gannett, Fleming, Corddry

and Carpenter Inc. Cross Keys Quadrangle,

West Block, Suite 345 Baltimore, MD 21210

Dennis T. Burton Johns Hopkins Univ. Applied Physics Lab. Aquatic Ecology Section Shady Side, MD 20867

Victor Cabelli Univ. of Rhode Island Dept. of Microbiology Kingston, RI 02881

A.C. Carpenter P.O. Box 9 Colonial Beach, VA 22443

Lewis E. Carr Univ. of MD Rt. 5, Box 285 Salisbury, MD 21801

Edward W. Christoffers Nat. Marine Fisheries Serv. Railroad Ave. Oxford, MD 21654

Lee dayman MD State Water Quality Advisory Comm. Office of

Envir. Progms. 3206 Floral Park Rd. Brandywine, MD 21613

Charles Coale Dept. of Agri. Econ. VPI and State Univ. Blacksburg, VA 24061

Marcia M. Collins Baltimore City DPW Waste Water Engin. 305 Municipal Office Bldg. Baltimore, MD 21202

K. Marlene Conaway Anne Arundel County Office

of Planning & Zoning Arundel Center Annapolis, MD 21401

James B. Coulter MD Dept. of Natural Resources Tawes State Office Bldg. Annapolis, MD 21401

Kitty Cox Citizens Program for Chesapeake Bay Rt. 1., Box 104B King William, VA 23086

L. Eugene Cronin Chesapeake Research Consortium 1419 Forest Dr. Suite 207 Annapolis, MD 21403

Alice Cronin 12 Mayo Ave. Bay Ridge Annapolis, MD 21403

William B. Cronin Chesapeake Bay Institute 4800 Atwell Rd. Shadyside, MD 20867

William Davis Grice Marine Biological Lab. 205 Fort Johnson Charleston, SC 29412

R. Dennen

Norton Dodge Chesapeake Bay Commission Turner, MD 20636

Douglas A. Dotson Dept. of Chemistry Univ. of MD Box 154 College Park, MD 20742

Page 207

Chlorine Conference Registrant

T. Marshall Duer, Jr. Magothy River Assoc. 4625 Falls Rd. Baltimore, MD 21209

William DuPaul VA Institute of Marine

Science Gloucester Pt., VA 23062

Ajax Eastman MD Conservation Council 112 E Lake Ave. Baltimore, MD 21212

Emory "Pie" Edwards Kent County Comm. Court House Chestertown, MD 21620

Hugh Egborn VA State Health Dept. 109 Governor St. Richmond, VA 23219

William Eichbaum MD Dept. Health and Mental

Hygiene 201 West Preston St. Baltimore, MD 21201

Kathy Ellett League of Women Voters of MD 1713 Fillmore Ct. Crofton, MD 21114

Donald Elmore MD Water Management Admin. 201 West Preston St. Baltimore, MD 21201

Thomans Ernst

Clifford A. Falkenau Anne Arundel County Envir.

Affairs Comm. 1878 Burley Dr. Annapolis, MD 21401

Helen W. Falkenau 1878 Burley Dr. Annapolis, MD 21401

1 (Continued)

Clare M. Fetrow 5404 Decatur St. Hyattsville, MD 20781 (MD Div. of Izaak Walton League

of American Study Comm. on Chlorine)

Frances H. Flanigan Citizens Program for Chesapeake Bay 6600 York Rd. Baltimore, MD 21212

Charles Frisbie Tidewater Admin. Dept. of Natural Resources Tawes State Office Bldg. Annapolis, MD 21401

P.H. Gamett Supt. of Engineering, Dept. of

Environment, London, England 2 Marsham St. London, England SWIP3EB

Mary Jo Garris 129 Severnway Rd. Arnold, MD 21012

Eugene L. Geiger Univ. of MD Horn Point Lab.-CEES Cambridge, MD 21613

Dan Gill Remlik Hall Farm Remlik, VA 23175

Nancy Goell Mid-Atlantic Fishery Management

Council Rm. 2115 Federal Bldg. Dover, DE 19901

John Gottschalk Citizens Program for Chesapeake

Bay 1412 16th St. Washington, D.C. 20036

John A. Grant Kent County Health Dept. Deputy State Health Officer P.O. Box 359 Chestertown, MD 21620

Page 203

Chlorine Conference Registrants

David J. Greene MD Envir. Serv. 60 West St. Annapolis, MD 21401

Ron Gregory- Bureau of Surveillance and

Field Studies VA State Water Control Bd. Richmond, VA 24230

L. Stephen Guiland PEPCO 1900 Penn Ave., N.W. Washington, DC 20068

James E. Gutman Citizens Program for

Chesapeake Bay Citizens Steering Comm. 233 Wiltshire Lane Severna Park, MD 21146

Evelyn Hailey VA General Assembly 1535 Versailles Ave. Norfolk, VA 23509

Robert Hailey 1535 Versailles Ave. Norfolk, VA 22509

Linwood W. Hall, Jr. Johns Hopkins Univ. Applied Physics Lab. Aquatic Ecology Section Shady Side, MD 20867

Tina Hall c/o Linwood Hall Johns Hopkins Univ. Applied Physics Lab. Shady Side, MD 20867

Bernard F. Halla ' Dept. of Natural Resources MD Wildlife Admin. Tawes State Office Bldg.

olis. MD 21401

(Continued)

Heyward Hamilton Div. of Biomed. Research Dept. of Energy Washington, DC 20545

Walter B. Harris Citizens Program, for Chesapeake Bay Citizens Steering Committee Blooming Neck Farm Thorton, MD 21678

George Helz Dept. of Chemistry, Univ. of MD College Park, MD 20742

Carl J. Hoicomb Springhill Farm Rt. 2, Box 385 Blacksburg, VA 24060

Don Jaworske Dept. of Chemistry Box 208 Univ. of MD College Park, MD 20742

Ed Jones

Margaret Jones and four Students Richmond Community High 113 West Moore St. Richmond, VA 23220

Sally P. Kanchuger 7034 Strathmore St., Apt. 107 Chevy Chase, MD 20015 (Member: League of Women Voters/ Mont. County)

Mary Kasper Citizens Program for Chesapeake Bay 3 Georgetown Ct. Annapolis, MD 21403

William Keesler The Virginian-Pilot 150 \<l Brambleton Rd. Norfolk. VA 23501

Page 209


Nancy Kelly Coastal Resources, Inc. 329 Riverview Terrace Annapolis, MD 21401

Ginger D. Klingelhoefer Office of Planning & Zoning The Arundel Center, A.A.Co. Annapolis, MD 21401

Harry Kriemelmeyer Box 460-Govemors Science

Adv. Coun. (MD) College Park, MD 20740

Christian Kurrle Arundel Beach Assoc. 408 Henderson Rd. Sevema Park, MD 21146

Chae Laird Continental Shelf Assoc.

Thomas Lawson Agri. Engr. Dept. Univ. of MD College Park, MD 20742

Norman LeBlanc Technical Services Div. Hampton Roads Sanitation

District Virginia Beach, VA

Stuart Lehman Chesapeake Bay Foundation 162 Prince George St. Annapolis, MD 21401

Jean Levesque

Patrick Lynch MD Bay Pilots Assoc. 1316 Bayliss St. Baltimore, MD 21224

Jeanette B. Lyon MD Dept. of Health & Mental

Hygiene Community Health Management

Program 201 West Preston St. Baltimore, MD 21201

(Continued)

Maarten Maarschalkerweerd 808 Riverside Dr. Arnold, MD 21012

Joseph Macknis EPA Chesapeake Bay Prog. 2083 West St. Annapolis, MD 21401

Terrance Martin Martin, Labell P.O. Box 2057 Newport News, VA 23602

Donald W. Mathias City of Norfolk Envir. Serv. 809 City Hall Bldg. Norfolk, VA 23501

Karen L. Mayne US Fish & Wildlife Serv. P.O. Box 729 Gloucester Point, VA 23062

John S. Maynes Whitman, Requardt & Assoc. 2315 St. Paul St. Baltimore, MD 21218

Tony Mazzaccaro MD Sea Grant Prog. H.J. Patterson Hall, Room 1224 Univ. of MD College Park, MD 21742

David McGrath Director, Chesapeake Bay Foundation 162 Prince George St. Annapolis, MD 21401

Mr. & Mrs. W.S. Miller

Myron H. Miller MD Dept. Legislative Reference 90 State Circle Annapolis, MD 21401

Larry D. Minock Council on the Envir. 903 9th St. Office Bldg. Richmond, VA 23219

Page 210


Walter McMann C&O Canal Nat. His. Pk. Rt. 1, Box 41 Summit Pt., WV 25446

Cranston Morgan Whitestone, VA 22578

Michael J. Oesterline Marine Advisory Ser. VA Institute of Marine

S c ience Gloucester Point, VA 23062

Vincent Olivieri Envir. Health Dept. Johns Hlpkins Univ. Baltimore, MD 21218

Barbara W. O'Neill League of Women Voters of MD 1171 Winch Rd. Port Deposit, MD 21904

Mike Paparella Univ. of MD Crisfield, MD 21817

Randy Parden

Manu Patel Bait. City DPW-Waste Water

Engin. 305 Municipal Office Bldg. Baltimore, MD 21202

Bill Pinschmidt

Suzanne Pogell Chesapeake Bay Center for

Estuarine Studies, Smith- sonian Institution

P.O. Box 28 Edgewater, MD 21037

LeLois M. Powell Univ. of MD Microbiology Dept. Sea

Grant Prog. 2131 Skinner Hall College Park, MD 20742

(Continued)

William E. Purcell VA Water Control Board P.O. Box 669 Kilmarnock, VA 22482

Merilyn Reeves 16506 Forest Mill Court Laurel, MD 20810

J. Brian Reichley Capital Control Company 210 Advance Lane Colmar, PA 18915

Jeffrey Rein

David L. Resh, Jr. MD Dept of Health & Mental Hygiene Community Health Management Prog. 201 West Preston St. Baltimore, MD 21201

Catherine I. Riley 20 Office St. Bel Air, MD 21014

E. Gordon Riley Magothy River Assn. 410 Henderson Rd. Severna Park, MD 21146

Morris Roberts VA Institute of Marine Science Gloucester Pt., VA 23062

G. Glynn Rountree Chesapeake Research Consortium 1419 Forest Dr., Suite 207 Annapolis, MD 21403

Allan Rubin Chief, Water Criteria Section USEPA Washington, DC 20460

Cappie Rue P.O. Box 4323 Belle Haven, VA 23306

Page 211


Calmet Sawyer Bureau of Wastewater Engin. VA State Health Dept. 109 Governor St. Richmond, VA 23219

0. Karl Scheible HydroQual, Inc. 1 Lethbridge Plaza Mahwah, NJ 07430

Donald V. Schlimme, Jr. Univ. of MD Horticulture Dept. College Park, MD 20742

Taylor Seay Northern Neck of VA Audubon

Society Rt. 1; Box 72B5 Kilmarnock, VA 22482

Dick Sedgley 1400 Brander St. Richmond, VA 23224

Richard B. Sellars, Jr. State of MD Water Mgmt. Admin. 201 West Preston St. Baltimore, MD 21201

Henry Silbermann MD Dept. of Natural Resources Tawes State Office Bldg. Annapolis, MD 21401

Gerry Slattery Patapsco WWTP 3501 Asiatic Ave. Baltimore, MD 21226

Linda Smeyne Office of Envir. Programs Water Management Act. 201 West Preston St. Baltimore, MD 21201

Amar Sohkey Baltimore City DPW-

Waste Water Engin. 305 Municipal Office Bldg. Baltimore, MD 21202

> (Continued)

Guenter Spohr P.O. Box 255 Cambridge, MD 21613

Kevin Sullivan Chesapeake Bay Center for Estuarine

Studies, Smithsonian Institute P.O. Box 28 Edgewater, MD 21037

Michael Sullivan Metropolitan Washington Council

of Gov'ts. 1875 Eye St., N.W., Suite 200 Washington, D.C. 20006

Vernon B. Sultenfuss Queen Anne's Co. Comm. Rt. 3, Box 89 Centreville, MD 21617

James Taft

Jeremiah Valliant Citizens Program for Chesapeake Bay P.O. Box 215 Oxford, MD 21654

R.E. Vazquez 1400 Brander St. Richmond, VA 23224

Richard H. Wagner ^ Coastal Resources Div.-Tidewater

Admin. Dept. of Natural Resources Tawes State Office Bldg. Annapolis, MD 21401

Donn R. Ward VA Tech Food Science & Tech. Dept. P.O. Box 369 Hampton, VA 23669

H.H. Ward Citizens Program for Chesapeake Bay 213 Oldfield Pt. Cir. Elkton, MD 21921

Charles Watkins 1631 Suters Lane, N.W. Washington, D.C. 20007

Page 212

Chlorine Conference Registrants

Bud Watson Chesapeake Bay Foundation 213 Oldfield Pt. Cir. Elkton, MD 21921

Ronald M. Weiner Univ. of MD Microbiology Dept. Skinner Hall College Park, MD 20742

Horace Wester National Park Ser. USDI Washington, DC

Fred Wheaton Univ. of MD Agri. Engr. Dept. College Park, MD 20742

James Wheeler USEPA Municipal Technology Branch WH-547EPA Washington, DC 20460

Chris White Chesapeake Bay Foundation 162 Prince George St. Annapolis, MD 21401

John C. White, Jr. VA Electric & Power Co. P.O. Box 26666 Richmond, VA 23261

Cloyde W. Wiley Bureau of Shellfish Sanitation VA State Health Dept. 109 Governor St., Rm 1117 Richmond, VA 23219

Gerald W. Winegrad District 30B-MD House of

Delegates Lowe House Office Bldg. Rm. 212 Annapolis, MD 21401

(Continued)

William S. Wolinski Water Quality Management Office 305 Municipal Bldg. Baltimore, MD 21202

Wayne C. Wren Pure Water Systems, Inc. 4 Edison Place Fairfield, NJ 07006

David A. Wright Chesapeake Biological Lab. Univ. of MD, Center for Estuarine

& Environ. Studies Box 38 Solomons, MD 20688

Mary P. Wright Bureau of Shellfish Sanitation VA State Health Dept. 109 Governor St., Rm. 1117 Richmond, VA 23219

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