ED 086 493

TITLEINSTITUTION

P913 DATENOTEAVAILABLE FROM

EDRS PRICEDESCRIPTORS

ABSTRACT

DOCUMENT RESUME

SE 016 924

Water Pollution, Causes and Cures.Manufacturing Chemists Association, Washington,D.C.[73]19p.Manufacturing Chemists Association, 1825 ConnecticutAvenue, N. W., Washington, D. C. 20009 (Free)

MF-$0.65 HC-$3.29*Environment; *Environmental Influences; Industry;*Instructional Materials; *Pollution; ResourceMaterials; Technology; *Water Pollution Control;Water Resources

This commentary on sources of water pollution andwater pollution treatment systems is accompanied by graphicillustrations. Sources of pollution such as lake bottom vegetation,synthetic organic; pollut,nts, heat pollution, radioactive substancepollution, and human and industrial waste. ptoducts are discussed.Several types of water purification treatments are presented withcut-away diagrams of the facilities and technical procedures. (JP)

FILMED FROM BEST AVAILABLE COPY

U 5 DEPARTMENT OF HEAL. THEDUCATION &WELFARENATIONAL INSTiTUTE OF

EDUCATHON

water pollutionCAUSES & CURES

--z-- ' NN \/ ,,,. --.......1-:: ....,\ \\

, \\ \

///,/

\ , /- /IL

.

'1111r1,44-,

kyv 460 'or Air I

4bp

MANUFACTURINGCHEMISTS

ASSOCIATION1825 CONNECTICUT AVENUE. N W WASHINGTON. D. C 20009

Founded in 1872, the

Manufacturing Chemists Aszociation

is the oldest chemical

tr?rie organization in the

Western Hemisphere.

Its member companies

represent more than 90 percent of

the production capacity of

basic industrial chemicals

within the United States

and Canada.

WaterPollutioncauses& cures

If man were still few in numbers and nomadic, hecould move on once his habitat became defiled.

If man were still primitive, he would not needmodern shelter, clothing, food, medicine, communi-cation and transportation.

If the human body was environmentally perfect, itwould not discharge wastes.

If the human body did not have certain needs ordesire certain comforts and conveniences, manu-facturing processes which give rise to potentialpollutants would not exist.

In fact, if nature were ecologically perfect, pollu-tants would not be washed from the soil or leachedfrom the subsoil.

The combination of these imperfections, however,make water a chemically complex commodity whosetrue identity is unknown to most laymen.

At home and at work, we flush a variety of mate-rials down the drain; in recreation, we may tossthem into streams or lakes, thoughtless as to howthey insult our common, priceless resourcewater.

Yet we are quick to complain when water is notusable for a particuiar purpose. We may even bridleat the rising cost of water and oppose expendituresessential to waste water conservation and treatm it.

The purpose of this booklet is to explain the com-plexity of water pollution problems and to encouragetheir amelioration and prevention.

William J. DriverPresidentManufacturing Chemists Association

4

,

Many people. define a water pollutant as anythingput into water which was not there in its natural state.

However, water's natural state varies with locale.So, they must mean pure water. In other words, 100percent distilled water, which is fine fcr automobilebatteries, steam irons and the like. But, what does ittaste like? Peanuts' Lucy would have a word for it,"Bleak!"

Even delicioustasting spring water is not pure inthis sense. It has just the right combination ofmineralschemical impuritiesput there by nature,to titillate our taste buds. Yet these same minerals,in sufficient amount, could eventually clog a steamiron or shorten the life of a car battery.

On the other hand, the right amount of chlorineadded to swimming pool water purifies it by keepingit germ-free. Spray it on grass, however, and it mayturn brown.

Or, consider plant nuilients, such as nitrogen andphosphorous. A farmer would welcome some in irri-gation water. But, in ponds or lakes; too muchnutrient may stimulate algal growth and use up thewater's dissolved oxygen. If algae multiply to excess,other aquatic lifefish, plants and the likecannotsurvive.

Therefore, any definition of water pollution mustbegin with, "It all depends . . ." Any substance canbe a pollutant if too much of it is present and howmuch is too much depends on the water use whichis involved.

Conversely, the presence or addition of somechemical substances in the right amount may bebeneficial or, at least, not harmful to particularwater uses. Under such circumstances they are ne.polluting.

There are eight general categories of water pol-lutants:

Organic . . .

. or oxygen-demanding wastes. They come fromhuman, animal and plant life; from food processingand certain other manufacturing procedures.

Nature breaks down such wastes in a mannervery much like digestion of food in the humanstomach. The metabolism of food in the huma:1 bodyrequires oxygen, supplied through the lungs andblood stream.

In like mariner, acquatic life requires a certainamount of organic "food" and oxygen. This "diges-tive" process i3 called biological degradation andthe measure of oxygen required to sustain it iscalled Biochemical Oxygen Demand.

In a sense, water breathes to obtain oxygen justas we do and the amount of oxygen present in wateris that which is dissolved in it. If we exert ourselves,we breathe harder to get more oxygen. If water isaeratedstirred upit, too, tends to absorb all theoxygen it can hold.

Since fish and other aquatic life depend on bothorganic food and oxygen to survive, the amount ofoxygen - demanding wastes and their rate of dischargeinto a given Cody of water must be controlled.

Disease-causing wastes

. . . which also come from humans, animals andfrom some manufacturing processesespeciallymeat packing and tanning operations.

Although modern disinfectants minimize the dan-ger from such pollutants, they must be carefullycontrolled and constantly waLched. Some disease-causing microbes develop resistance to disinfectionand new formulas must be created.

Plant nutrients ...

... such as nitrogen and phosphorus compounds,which are essential to plant growth. Small amountsare present in natural waters. Large amounts arecontributed by sewage, cernin industrial wastes andland drainage. Biological degradation utilizes thesesubstances in mineral form as fertilizersthe waynature intended if.

Pollution problems develop when excessiveamounts get .into water, especially lakes or poodswhere the water has little flow, since algal and waterplant growth may be over-sti;Aulated.

Toxic substances ...

. . . in the form of synthetic organic compoundssuch as solvents, cleaning agents and bug killers,and inorganic substances such as mineral salts andacids. Some of these cause taste or odor problems.Others are toxic even in low concentrations.

Persistent substances ...

... which are not normally biodegradable. Certainorganic compounds are in this category; and inor-ganic materials are not subject to biological break-down, anyway. They get into water from naturalsources due to rainfall run-off, seepage, and, to aconsiderable degree, from agricultural practices andvarious industrial operations.

Sediments ...

... which are particles of soil, sand and mineralsconveyed in water as silt from land run-off and high-

way and building construction.These can be a major problem because of their

magnitude. They settle to the bottom of rivers andharbors, requiring expensive dredging; get intoreservoirs, reducing their capacities and useful life;erode power turbines and equipment and reducefish and shellfish populations by covering theirsources of food. If organic, they may decompose andexert additional oxygen demand.

Radioactive substances ...

. . . which result from mining and processingradioactive ores and the use of refined radioactivematerials for industrial, medical and research pur-poses. They also result from fallout following nuclearweapons testing in the atmosphere.

Heat ...

... which speeds up the rate of biological degrada-tion. Power and manufacturing plants using waterfor cooling purposes must, in some instances, coolthe cooling water before releasing it.

Summer temperatures also contribute to thermalpollution problems. Warm water holds less oxygenand absorbs less from the air, disturbing the oxygenand biological balance.

PROBLEM

Population and industrial expansion during thelast 50 years has vastly increased the volume ofpotential water pollutants so that, in some instances,nature's self cleansing c pabilities are overwhelmed.Where this is so, the problem is man-made anddemands man-made solutions.

Sewers collect the wastewater from homes, build-ings and many industries and deli.ier it to treatmentplants which are supposed to ma it fit for dis-charge into rivers or streams or for reuse. Some ofthese systems are efficient, others are not. Many areinadequate for today's pollution control require-ments. This is not due to a lack of knowledge.Technically, most water pollution can be controlled.The deterrent has been planning, financing, buildingand operating facilities io meet rapidly-increasingneeds.

There are two kinds of sewer systems--combinedand separate.

Combined sewers carry water polluted by humanwastes and storm water that drains off buildings,streets and land.

Separated sewers divide up those two sources.One--called a sanitary sewercarries only the waterpolluted by human waste. The othercalled a stormsewertakes care of rainfall, melting snow andstreet washing.

Except in rural areas where there is no seweragesystem, or in others where septic tanks are used,every home and building has a pipe which carrieswastewater and sewage to a larger sewer beneath anearby street. These are connected to trunk or mainsewers. In a combined system, these flow into a stilllarger sewer called an interceptor which is designedto cart)/ several times the normal dry-weather flow.

During dry periods, all the sewage goes from theinterceptor to a waste tioatment plant. However,during a storm, part of the waterincluding varyingamounts of raw sewagemay bypass the plant andgo directly into receiving streams. Only the amountthe plant is equipped to handle is treatedobviouslynot an ideal situation. Much research is under wayon methods of solving the problem of combinedsewers.

Ir separate sewer systems, storm water carriessediment, oil, grease and other pollutants fromlawns, sidewalks, driveways, streets, roofs and con-struction sites. As a result, urban storm water isbecoming more recognized as a cause of waterpollution.

11111114*-4\-1

-4*\-1"4/1111111141

' CONTROLLED

FLOW

4

0

401

47,..4

.4

44IP

f4'411111%..

Co4,18/4,0

1141016.-

-14

111111111111WHIPm

cure

Sanitary wastes. and residual wastes from indus-trial operations remaining after other means -,reused to restrict and control them, may be treated tominimize adverse effects on water and the aquaticenvironment.

Primarynamely, first stagetreatment is a

physical separation process to remove undissolvedsolid materials.

As the sewage enters the treatment plant, it mayflow through screens to remove rags, sticks andother floating objects. The screens vary from coarseto fine and are usually slanted in a receptacle sothat the debris can be scraped off and disposed of,generally as land fill.

Some plants grind these objects so they remainin the sewage flow to be removed later in a settlingtank.

After the sewage has been screened or ground, itpasses into a grit chamber where dense materials,such as sand, cinders and small stones settle to the

BASIC WASTEWATER TREATMENT (Primary)

Screen Grit Chamber Settling Tank

(Secondary)

Activated Sludge

Aeration Tank ClarifierLim

Raw

WasteAirs

DigesterI

PrimarySludge

Excess Sludge

Vacuum FiltrationIncineration

econdarEffluent

Excess

inert Sterile Ash

bottom. This step is essential to combined sewersystems because run-off from streets and lawnsends up at the treatment plant. The settled materialis normally washed and used as land fill.

Some plants use another screen after the gritchamber to remove any additional material whichwould damage equipment or otherwise interfere withsubsequent processing.

At this point, sewage still contains undissolvedsuspended matter which can be removed in a settlingtank or .primory clarifier. There, it gradually sinks tothe bottom, forming a mass called raw sludge. Thesludge is drawn off into a digester, which concen-trates it for use as land fill. In some 'nstances, theconcentrated sludge is burned and the ash used asland fill.

The remaining liquid from the settling tank iscalled primary effluent, and if only primary treatmentis applied, it may be disinfected with chlorine to

destroy disease-caushig bacteria and reduce odorsbefore being discharged.

Secondary treatment, applied to sanitary sewage,can further remove organic matterup to 90 percent s-by making use of the bacteria in it. The bio-logical oxidation effected is the same in the twoprincipal types of processing units:

Trickling filters .

. . which are beds of stones several feet deepthrough which the wastewater trickles. Bacteria ad-here to the stones and consume most of the organicmatter. The treated water is led out through pipingfrom the bottom of the filter. After suspended mattersettles out, it may be disinfected with chlorine beforebeing discharged.

However, the trend in secondary treatment is

toward .

ADVANCED WASTEWATER TREATMENT (Tertiary or Physical-Chemical)

Coagulation-Sedimentatione Flocculation Clarifier

I J

Activated Lime Sludge

9n optional)

Sludge to sludge Treatment

Carbon Adsorption

Filtration

Ion Exchange

Chlorine

P

Clean Water

. . . ACTIVATED SLUDGE

PRIMARY EFFLUENT IAERATION TANK

888_ 38888

ACTIVATED SLUDGE

CLARIFIER

J

I_ SECONDARYEFFLUENT

EXCESS

SLUDGE

1111110111111WIn the activated sludge process, primary effluent

is pumped to an aeration tank and combined withbiological sludge to create "mixed liquor," which isaerated for several hours. The process must be care-fully controlled since the quantity or organic mattervaries constantly and the proper amounts of oxygenand biological sludge must be provided so the bac-teria can do their job.

After aeration, the mixed liquor then flows to asedimentation tank for removal of the biologicalsludge, part of which is recycled back to the aerationtank. The remainder goes to a digester where it istreated the same as raw sludge from primary treat-ment. The liquid effluent may be chlorinated beforerelease.

TERTIARY TREATMENT . .

.. is what its name implies, a third step in waterpollution control. There are several such "advancedtreatment" techniques, ranging from extensions ofbiological treatmentwhich remove nitrogen, phos-phorus and other nutrientsto physical/chemicalseparation. One or more may be used to meet spe-cific needs. They include:

Chemical Oxidation ...

. . . which utilizes oxidants such as ozone andchlorine. The process does not remove anything inthe water but has been used for many years toimprove the taste and odor qualities of municipaldrinking water, It does so by destroying or alteringorganic constituents in drinking water which may bepresent in very small quantities. For special purposeschemical oxidants are also useful for treating waste-waters.

Coagulation-Sedimentation ...

. . . wherein alum, lime or a selected organicpolymer is added to the screened sewage or to theeffluent as it comes from biological treatment. Itthen passes through flocculation tanks where thealum or lime causes the smaller suspended particlesto bunch together (floc) into larger masses, makingthem settle faster and easier to remove.

ADSORPTION

10.41tt-t4;.ize4t,

Adsorption . . .

. . is another form of tertiary treatment whichmay be needed to remove organics that resist normalbiological treatment.

The effect of such organics in water varies, de-pending chi the particular substances involved. Somemay cause taste and odor problems, foaming, taint-ing of fish and even fish kills.

Adsorption uses activated carbon and can beapplied in either of two waysby passing the waste-water thr -gh a bed of activated carbon granules orby putting powdered activated carbon directly intothe wastew8 ter.

Carbon granules can remove nearly all of the dis-solved organic matter and the granules can be re-use-1 after regeneration by heat with due regard notto cause air pollution.

Powdered carbon is highly efficient but mare diffi-cult to handle, since the particles must be removedas sediment. Also, regeneration and reuse of groundcarbon is more complicated.

Except for dissolved salts, municipal wastewaterthat has gone through the processes described vhusfar can be restored to quality comparable to thatbefore it was used. In wastewater treatment lan-guage, dissolved salts mean any mineral dissolvedby waterduring rainfall, seepage through soil ortrickling over rocks as well as those present in hu-man and animal waste. Their removal requires adifferent kind of tertiary step . . .

... Desalination

Several methods are available. AU are expensive.They include:

Ion exchange ...

. . . which uses special types of synthetic resinscharacterized by either a positive or a negativeelectrical charge. In simple terms, this is how theywork:

When dissolved in water, a mineral salt breaksdown into ions. An ion is an atom or small group ofatoms having an electrical charge, either positive ornegative. Example: common table salta combina-tion of sodium and chlorine which we see as whitecrystals. However, when dissolved in water, thesodium and chlorine occur as ions we cannot see.Sodium ions are positive, chlorine ions negative.

CLARIFIER

When poured into or through a container contain-ing the right combination of electrically charged ionexchange resins in the form of small plastic beads.opposites attract. Positive beads attract and holdchlorine ions; negative beads, sodium. Salt-free waterremains. Steam-iron water puriftrs are a simpleversion of ion exchange.

When the plastic beads have attracted all the ionsthey can hold, they may be regenerated by puttingthem through a reverse process whereby they releasethe ions they have attracted. This produces a con-centrated salt solution which may or may not beuseful. If the latter, it must be disposed of; forinstanceit may be pumped to a holding basinwhere the moisture evaporates, leaving the saltsbehind.

Electrodialysis

. . . is a complicated and costly process using

ION EXCHANGER

FROM

AERATIONTANK

SLUDGE

SALT FREEWATER

electricity and membranes. The membrane is madeof a chemically-treated plastic and thp salts aredrawn out of the water by negative and positiveelectrodes. The end result is similar to ion exchange.Disposal methods for the remaining salts vary con-siderably, depending on type and quantity.

Reverse Osmosis ...

. . . is a process based on this natural phe-

nomenon:

When liquids with different concentrations of

mineral salts are separated by a porous membrane,molecules of pure water tend to pass by osmosisfrom the less concentrated to the more concentratedside until they are equal. When pressure is applied,the flow can be reversed.

Scientists are taking advantage of this reverseprocess, which means taking good water out of

CLARIFIEDWATER

WATERVAPOR

wastewater rather than decomposing or otherwiseremoving the waste.

The practical application of reverse osmosis isrelatively expensive, however, and is continuing tobe developed.

Distil lattion

. . . is the ultimate in producing pure water. Aneffluent, or any kind of water, is brought tc a boil.The steam is collected and allowed to cool back intowater. On a large scale. distillation can be expensiveand is applied only to special purposes.

As mentioned at the beginning, 100 percent dis-tilled water is excellent for steam irons and carbatteries. It is essential to some manufacturingprocesses. Yet, for drinking, Lucy's "Bleah" is mostdescriptive.

CONDENSATETANK

HEATCOILS

CONCENTRATED BRINE

SALT FREEWATER

conclusionAll wastewater treatment methods, even aistilla-

tion, leave something behind that must be disposedof. The scale inside a tea kettle is an everydayexample. Thus, keeping water in useful condition isa never-ending cycle.

Water pollution can be controlled, however,through the application of technology, none of whichwould be possible without the chemical industry. Ithas created and currently manufactures a majority ofthe essential materials described in this bookletoxygen, chlorine, alum, lime, activated carbon,polymers, ion exchange resins, plastic membranesand filters.

In addition, the basic chemical industry has in-vested millions of dollars to control water pollutionfrom its manufacturing facilities. Many more millionsare spent every year to operate wastewater treat-ment facilities, to provide surveillance and to con-duct extensive research which improves presenttechnology and develops new processes.

On March 20, 1972, the Manufacturing ChemistsAssociation announced the results of a survey whichis illustrated on the opposite page. It leaves no doubt

as to the long-time dedicaticn of the chemical indus-try in protecting the environment.

In revealing cost factors covering air pollution,water pollution and solid wastes disposal, the surveyshows that up to 1972, 137 Association membercompanies had invested $700 million in capitalequipment to control water pollution alone. This com-pares with $264 million a decade earlier and $385million as of 1967. These companies predict theircapital investment by 1976 will reach $1.3 billion.

For this same purpose, annual operating andmaintenance expenditures by these companies alsoincreased over the years: $40 million in 1962, $60million in 1967 and $121 million in 1972. And, re-search expenditures in water pollution control morethan quadrupied: $5.5 million in 1962, $9.3 millionin 1967, $24.7 million in 1972.

Full-time personnel engaged in the operation andmaintenance of water pollution control equipment inthese companies has doubled in the last 10 years:1,765 were involved in 1962; 2,096 in 1967, andmore than 3,500 by 1972.

ACTUAL OPERATION

AND PROJECTED AND MAINTENANCECAPITAL INVESTMENT COSTS OF

FOR WATER WATER POLLUTION

$385MILLION

$264MILLION

$700MILLION

$1,357MILLION

$40MILLION

$60MILLION

$121MILLION

RESEARCH MANPOWER

EXPENDITURES ASSIGNED

ON WATER TO WATERPOLLUTION POLLUTION

CONTROL CONTROL

$5.5MILLION

$9.3MILLION

$24.7

1,765PEOPLE

1962 1967 1972 1976 1962 1967 1972 1962 1967 1972

NUMBER OF REFORTING COMPANIES: 1962-125 1967-129 1972-137

SOURCE: Manufacturing Chemists Association

2,096PEOPLE

3,503PEOPLE

1962 1967 1972

postscript

The expressed goal of the United States Govern-ment is to make the nation's water clean enough forswimming and for the propagation of aquatic life by1981. The price of achieving that objective may bemodest in rural areas or small communities.

However, the cost increases rapidly itii urban areaswhere concentration of households and industriescreate overwhelming amounts of sewage and otherpollutants. Just how fast it increases in each instanceis a matter of conjecture and a dozen experts willcome up with a dozen different answers. No one canbe absolutely sure of the ultimate price until everyfacet of the local situation is evaluated, facilitiesconstructed and a treatment plant put into operation.However, since this booklet was written in Washing-ton, it is possible to cite this specific example:

As 1972 began, the Blue Plains treatment plant inthe District of Columbia was handling 275 milliongallons of sewage from nearly two million residentsin a portion of the National Capital Areathe Districtitself and several adjacent counties in Maryland anaVirginia. The plant is inadequate for the job. /tsactivated sludge installation provides only a 70-75percent waste reduction and the receiving river, thePotomac, is unfit for swimming or fishing.

This is understandable. Blue Plains was built in1938 as a primary treatment plant only. Expansionto an activated sludge, process took place in the1950's, with sporadic improvements since then.Although the cost of the plant in terms of today'sdollars is nearly impossible to estimate, the 1972budget to operate it was $4.5 million.

Now, a new Blue Plains combined sewer treatmentfacility is under construction. Due for completk-n byJanuary 1975 it will:

Cost $360 milliol. to build.

Require $22-$25 million-a-year to operate.

Handle a normal load of 309 million gallons ofsewage, with a peak capacity of 650 milliongallons.

Be capable of handling an additional 290 milliongallons of storm water for primary treatment only.

Remove 97 percent of organic (oxygen-demand-ing) wastes and phosphorous, and 85 percent ofthe nitrogen prior to discharging its effluent.

The new plant will not solve all the Potomac'sproblems. Silt from construction sites and pollutantswashed from streets will continue to get into it.However, when in operation, the facility will be agiant step towards making the river suitable forswimming and the support of aquatic life.

In relating this example to situations in otherparts of the nation, it must be borne in mind thatthe Greater Washington area is not highly industrial-ized. Many of the pollutants common to majormanufacturing centers do not exist. It does mean,however, thatlike chemical manrfacturersallcommunities and industries will making hugeinvestments in pollution control equipment andspending large sums every year to maintain it inorder to restore and protect water for beneficialuses by mankind.

This booklet is written, edited and published by theCommunity Relations; Departmentof theManufacturing Chemists Association,Al lin G. Robinson, Manager.

Additic gal copies are free.Requests for more than 10 copiesrequire a letter describing intended distribution.

Art/design/printing byHennage Creative PrintersWashington, D. C.

Technical Advisors:

George E. BestTechnical DirectorManufacturing Chemists Association

Howard B. BrownAssistant Technical DirectorManufacturing Chemists Association

and the following members of the Association'sWater Resources Committee:

Clarence W. FisherKoppers Company, Inc.

Albert H. Lasday, Ph.D.Texaco, Inc.

Henry C. Marks, Ph.D.Pennwalt Corporation

William R. TaylorDiamond Shamrock Chemical Company

also

Robert R. PerryChief, Water Pollution Control DivisionDistrict of Columbia