roughts, explosive popula-tion growth in arid parts of

the country, and the continuingview that water is an infiniteresource are reasons for watershortages in many areas acrossthe nation. In response to thisproblem, some wastewaterprofessionals are reusing treat-ed wastewater and have foundit to be a reliable alternativewater source.

In addition to conservinghighly treated, expensivedrinking water, wastewaterreuse reduces the release ofnutrient-rich wastewater intoenvironmentally stressedstreams and rivers.

“Wastewater can be viewedas a resource, fresh water con-taining plant nutrients (nitrogen,phosphorus, and potassium),”says John Sheaffer, Ph.D., presi-dent, Sheaffer International, Ltd.,Naperville, Illinois. “In thegroundwater, these nutrients area pollutant, but on a growingcrop or turf, they are a resource.When wastewater is reused, it isnot available to pollute thegroundwater supply.”

What is wastewater reuse?The term wastewater reuse is

often used synonymously withthe terms wastewater recyclingand wastewater reclamation.Because the general public oftendoes not understand the qualitydifference between treated anduntreated wastewater, many com-munities have shortened the term

lands. High-qualityreclaimed water is used to irrigate food crops.

• Recreational impound-ments—such as pondsand lakes.

• Environmental reuse—creating artificial wetlands,enhancing natural wet-lands, and sustainingstream flows.

• Industrial reuse—processor makeup water andcooling tower water.

Guidelines and RegulationsIn 1992, EPA developed

Guidelines for Water Reuse, a comprehensive, technical document. Some of the informa-tion contained in this manualincludes a summary of statereuse requirements, guidelinesfor treating and reusing water,key issues in evaluating waste-water reuse opportunities, andcase studies illustrating legalissues, such as water rights, that affect wastewater reuse.

EPA guidelines for three of the more common types of wastewater reuse are given in the table on page 47.

State Guidelines VaryMany states have guidelines

or regulations for the designand operation of wastewaterreuse facilities, but wide discre-tion in interpreting EPA’s guide-lines has resulted in standardsthat differ significantly acrossthe states. For instance, Texasprohibits using recycled water

to water reuse, which creates amore positive image.

The U.S. EnvironmentalProtection Agency (EPA) defineswastewater reuse as, “usingwastewater or reclaimed waterfrom one application for anotherapplication. The deliberate use ofreclaimed water or wastewatermust be in compliance withapplicable rules for a beneficialpurpose (landscape irrigation,agricultural irrigation, aestheticuses, ground water recharge,industrial uses, and fire protec-tion). A common type of recycledwater is water that has beenreclaimed from municipal waste-water (sewage).”

Reasons for Wastewater ReuseThe most common reasons for

establishing a wastewater reuseprogram is to identify new watersources for increased waterdemand and to find economicalways to meet increasingly morestringent discharge standards.

Types of ReuseWastewater reuse can be

grouped into the following categories:

• Urban reuse—the irrigationof public parks, school yards,highway medians, and resi-dential landscapes, as well asfor fire protection and toiletflushing in commercial andindustrial buildings.

• Agricultural reuse—irriga-tion of nonfood crops, suchas fodder and fiber, commer-cial nurseries, and pasture

46 On Tap Winter 2005

By Caigan McKenzie • NESC Staff WriterLayout by Chris Metzgar • Graphic Designer

to irrigate food crops while NewMexico allows surface irrigation offood crops where there is no con-tact between the edible portion ofthe crop and the treated waste-water. Some states, Pennsylvaniafor instance, are just beginning tolook at wastewater reuse.

Recent droughts in the water-rich state of Pennsylvania haveprompted water agencies to investi-gate wastewater reuse. “We arestarting to prepare an internal posi-tion paper on wastewater reuse formanagement review,” says RogerMusselman, chief of permit section,Pennsylvania Department ofEnvironmental Protection, Divisionof Wastewater Management,Harrisburg, Pennsylvania.”We hopeto establish guidelines within thenext two years.”

Pennsylvania’s experience inwastewater reuse is limited.

Community HealthProtection

In any reuse system,protecting public health is critical. Human expo-sure to disease-causingorganisms or other con-taminants in treated efflu-ent could cause seriouspublic health problems.For this reason, waste-water that could come in contact with the publicis treated at the tertiarylevel, which removes mostof the original pollutants.The most common disin-fectants used to remove or inactivate pathogenicorganisms are chlorine,ultraviolet light, and ozone.

Public EducationEducation is key to

overcoming public fearsabout a reuse system,particularly fears thatrelate to public healthand water quality. “Abroad, in-depth publicrelations program and ademonstration project areespecially helpful whenthe reuse project is thefirst of its kind in thestate,” says Curtis Stultz,assistant superintendent,

Wastewater Treatment Plant forthe City of Woodburn, Oregon.

The public can either be yourally or your worst nightmare.“Our citizens backed our project,but another Oregon communitywasn’t as fortunate,” Stultz says.“Their treatment plant wanted to create a plantation of hybridpoplar trees where it could dis-charge some of its treated indus-trial wastewater. The plantationsite was small, and the home-owner who lived next to the sitehad concerns about the project.Misconceptions about the treat-ment process, its effect on thegroundwater, and the use ofgenetically engineered trees led the homeowner to file suitagainst the wastewater treatmentplant. That incident was theimpetus for setting up regula-tions in Oregon for how poplartrees are planted.”

“We’ve used it to make artificialsnow and to spray irrigate acouple of golf courses,” Mussel-man reports. “In each instance,the state’s Department ofEnvironmental Protection’sregional office oversaw the project. Basically, we used ahigh-quality effluent for theseprojects, so the end result was a positive one.

“Our major problem rightnow is the lack of agreementamong the regions about therequired level of treatmentbefore reuse. Some regionsclosely follow EPA’s guidelinesand require tertiary treatment.Other regions think wastewaterwith a fecal coliform level of200 colonies per 100 mL is suffi-cient for irrigating a golf course.We really need to get everyoneon the same page.”

Treatment

Secondary1

Filtration2

Disinfection3

SecondaryDisinfection

Site specificSecondary anddisinfection (min.)May also needfiltration and/oradvancedwastewatertreatment

SetbackDistances

50 ft (15 m) topotable watersupply wells

300 feet (90 m)to potable watersupply wells

100 ft (30 m) toareas accessibleto the public (ifspray irrigation)site specific

Reclaimed WaterMonitoring

pH – weeklyBOD – weeklyTurbidity – continuousColiform – dailyCl2 residual –continuous

pH – weeklyBOD – weeklyTSS – dailyColiform – dailyCl2 residual –continuous

pH – dailyTurbidity – continuousColiform – dailyCl2 residual – continuousDrinking water standards– quarterlyOther – depends onconstituent

Reclaimed WaterQuality

pH = 6–9<10 mg/L biochemicaloxygen demand (BOD)< 2 turbidity units (NTU)5

No detectable fecalcoliform/100 mL4

1 mg/L chlorine (Cl2)residual (min.)

pH = 6–9< 30 mg/L BOD< 30 mg/L totalsuspended solids (TSS)< 200 fecal coliform/100 mL5

1 mg/L Cl2 residual(min.)

Types of Reuse

Urban ReuseLandscape irrigation,vehicle washing, toiletflushing, fire protection,commercial airconditioners, and otheruses with similar accessor exposure to the water.

Agricultural ReuseFor Non-Food Crops Pasture for milkinganimals; fodder, fiber andseed crops.

Indirect Potable ReuseGroundwater recharge byspreading into potableaquifiers.

Reuse Table

1 Secondary treatment processes include activated sludge processes, trickling filters, rotating biological contactors, andmany stabilization pond systems. Secondary treatment should produce effluent in which both the BOD and TSS do noexceed 30 mg/L.

2 Filtration means passing the effluent through natural undisturbed soil or filter media such as sand and/or anthracite.3 Disinfection means the destruction, inactivation or removal of pathogenic microorganisms. It may be accomplished by

chlorination, or other chemical disinfectants, UV radiation or other processes.4 The number of fecal coliform organisms should not exceed 14/100 mL in any sample.5 The number of fecal coliform organisms should not exceed 800/100 mL in any sample.

Source: U.S. Environmental Protection Agency. 1992. Guidelines for Water Reuse. (EPA)/625/R-92/004.

Site specific Meet drinking waterstandards afterpercolation throughvadose zone.

48 On Tap Winter 2005

Cross-Connection ControlIt is crucial to be able to differ-

entiate between piping, valves, andoutlets that are used to distributetreated effluent (reclaimed water)and those that are used to distrib-ute potable water. One methodused for this purpose is color-cod-ing components used to distributereclaimed water not intended fordrinking water. Another method isto post areas such as parks, ceme-teries, and yards with warningsigns stating the water is not forconsumption. Signage shouldreflect all the major languages inthe region. Florida, for instance,uses both Spanish and English.

“The City of St. Petersburg’scross-connection control program isnationally recognized as being oneof the most thorough programs inplace, especially for dual distribu-tion systems,” says Bruce Bates,manager of water reclamation, St.Petersburg, Florida. “We routinelyinspect homeowner and commer-cial systems to ensure they haven’tinadvertently tied their potablewater system into the reclaimedsystem. We require backflow pre-vention assemblies; and we havehose bibbs for the reclaimed line inan underground service box.”

Costs Some considerations for costs

include the type of reuse equipmentchosen, whether or not the reusesystem was constructed at the sametime as the treatment plant or addedon afterward, the level to which theeffluent is treated, and the distancethe treated effluent must travelbetween the treatment site and thedischarge site. Many communitieshave defrayed costs through low-interest loans and federal, state, andlocal grants.

In his abstract “Wastewater Reusefor Non-Potable Applications: AnIntroduction,” presented at the 2000International Symposium on EfficientWater Use in Urban Areas, TakashiAsano, Ph.D., P.E., University ofCalifornia, Davis, California, writes, “A common misconception in plan-ning for wastewater reclamationand reuse is that reclaimed waste-water represents a low-cost newwater supply. This assumption isgenerally true only when waste-water reclamation facilities are con-veniently located near large agricul-tural or industrial users and when

no additional treatment is requiredbeyond the existing water pollutioncontrol facilities from whichreclaimed water is delivered. Theconveyance and distribution systemsfor reclaimed water represent theprincipal cost of most proposed waterreuse projects. Recent experience inCalifornia indicates that approximate-ly four million U.S. dollars in capitalcost are required for each one millionm3 per year of reclaimed water that ismade available for reuse. Assuming afacility life of 20 years and a ninepercent interest rate, the amortizedcost of this reclaimed water is about$0.45/m3, excluding operations andmanagement costs.”

Wastewater reuse systems rangefrom very sophisticated and complexengineering processes to simple, nat-ural systems. A professional engineercan examine the various processesand components to design a systemthat best meets your needs.

Wastewater Reuse in FloridaIn 2001, Florida reused 584 million

gallons per day of treated wastewaterfor beneficial purposes.

“In Florida, it’s either feast orfamine,” Bates says. “Florida enjoysplentiful rainfall, but uneven distribu-tion of precipitation has causeddrought conditions, particularly inMarch, April, and May. To preservewater supplies, Florida’s state lawmandates that potable water be limit-ed for irrigation purposes.”

St. Petersburg, Florida, is home tothe oldest municipal dual distributionsystem in the United States, and oneof the largest in the world. The sys-tem supplies potable water throughone distribution network and non-potable water through the other.

The city’s four water reclamationtreatment plants handle more than 40million gallons of wastewater each day.When the water enters the plant, it isscreened through a bar screen structure

Some Wastewater Reuse Advantages and Disadvantages

Advantages:• This technology reduces the demands on

potable sources of freshwater.

• It may reduce the need for large waste-water treatment systems, if significantportions of the waste stream are reusedor recycled.

• The technology may diminish the volume ofwastewater discharged, resulting in a bene-ficial impact on the aquatic environment.

• Capital costs are low to medium for mostsystems and are recoverable in a veryshort time; this excludes systemsdesigned for direct reuse of sewagewater.

• Operation and maintenance are relativelysimple except in direct reuse systemswhere more extensive technology andquality control are required.

• Provision of nutrient-rich wastewaterscan increase agricultural production inwater-poor areas.

• Pollution of rivers and groundwaters maybe reduced.

• Lawn maintenance and golf course irriga-tion is facilitated in resort areas.

• In most cases, the quality of the waste-water, as an irrigation water supply, issuperior to that of well water.

Disadvantages• If implemented on a large scale, revenues

to water supply and wastewater utilitiesmay fall as the demand for potable waterfor non-potable uses and the dischargeof wastewaters is reduced.

• Reuse of wastewater may be seasonal innature, resulting in the overloading oftreatment and disposal facilities duringthe rainy season; if the wet season is oflong duration and/or high intensity, theseasonal discharge of raw wastewatersmay occur.

• Health problems, such as water-bornediseases and skin irritations, may occurin people coming into direct contact withreused wastewater.

• Gases, such as sulfuric acid, producedduring the treatment process can resultin chronic health problems.

• In some cases, reuse of wastewater isnot economically feasible because of therequirement for an additional distributionsystem.

• Application of untreated wastewater as irrigation water or as injectedrecharge water may result in ground-water contamination.

Source: Organization of American States. Water Reuse.Unit for Sustainable Development and Environment.www.oas.org/sp/prog/chap3_2.htm.

Photo by Susan Horvat

www.nesc.wvu.edu 49

to remove large debris and thengoes to a grit chamber to allow thesand and grit to settle. After set-tling, the water is biologicallytreated in special aeration basinsto allow billions of microorgan-isms to consume organics in thewastewater. After biological treat-ment, the water is filteredthrough deep bed, dual media fil-ters and then clarified. To com-plete the process, the water isdisinfected with chlorine.

The treated effluent flowsthrough 260 miles of pipe tomore than 10,000 homes andbusinesses, including 9,340 residen-tial lawns, 51 schools, 86 parks, sixgolf courses, and 11 commercialcooling towers. Forty million gal-lons of treated wastewater can bestored onsite; after that, the wateris stored 900 feet below the groundin deep well injection.

“The public loves the service,”Bates says. “Statistically, it takeswastewater from five homeown-ers to provide enough water forone lawn, so our biggest criticismhas been that we can’t serveeveryone. Currently, we serveapproximately 10 percent of ourpopulation.”

One reason the public hasresponded so favorably is thatreused wastewater is billed on aflat rate, not on consumption.“Using potable water would costbetween five to 10 times morethan reused wastewater,” Batessays. “When we first started theprogram back in the 1970s, no

poplar plantation tours, organizedschool science poplar projects,sent out flyers and mailers, andgot newspaper coverage,” Stultzsays. “We hired a retired publicrelations woman from the com-munity to assist us. We made surethat the community understoodwhat we wanted to do and howwe were going to do it. It was a lotof effort, but it was well worth it.”

In 1999, Woodburn was readyto discharge treated effluentthrough micro-spray sprinklersinto its newly developed poplartree plantation. “This was the per-fect solution for us,” Stultz said.“We have a lot of farmland aroundus, and the soil was adequate forthe application, so we didn’t haveto do much preparation work.”

“The great thing about poplartrees is that they grow quicklyand use lots of water,”he adds. “A four-year-old tree, for instance,would uptake 10.6 acreages ofwater. We generally produceabout two million gallons a dayof wastewater, and we can irri-gate the 88-acre plantation with1.5 million gallons a day duringour critical dry months from Junethrough September. The remain-ing one-half million gallons a dayis discharged to our receivingstream. Because the amount ofwastewater being discharged intothe stream has been greatlyreduced, the receiving stream isable to dilute the concentrationsof ammonia so that the levels arewithin regulations.” The amount

one was sure how the programwould be received, so it was mar-keted at a low, flat rate to winpeople over and was subsidizedthrough other revenues. Butcharging a flat rate was a big mistake. People don’t conservebecause there is no economicincentive associated with it. The$5 monthly user fee doesn’t comeclose to covering our capital andoperating costs for this service.”

St. Petersburg is setting up several pilot programs in whichmeters will be used to determineconsumption rates. “We’ll only begathering baseline data,” Batessays. “Moving from a flat rate to a consumption rate is a politicaldecision the mayor would have tomake, and it will require seriousdiscussion in order to convinceour customers.”

Reuse in Woodburn, OregonWhen the Oregon Department

of Environmental Quality revisedthe total maximum daily load forthe Pudding River, the city ofWoodburn had to decide betweenlowering the ammonia level in itswastewater or finding an alterna-tive discharge site. After investigat-ing a variety of options, Woodburnchose to refurbish its treatmentplant to include a wastewaterreuse facility.

Gaining public acceptance wasat the top of the list. “Managementput together a citizen’s committee,created an educational videoabout the facility, conducted

of wastewater taken into thetreatment plant slows down dur-ing the November rainy seasonwhen the receiving stream is nat-urally high, providing a greaterdilution factor for loadings.

Wastewater is treated using abiological nutrient removal aera-tion basin, a clarifier, and sandfil-ters, bringing it to tertiary treat-ment. Treated effluent is disinfec-ted in an ultraviolet unit and thendiverted into a basin for chlorina-tion. While this level of treatmentexceeds the requirements for anonfood crop, managementdecided to use the precautionssince the treatment plant had theequipment to do it.

After chlorination, the treatedeffluent is pumped into a mani-fold system that distributes it tothe poplar plantation through anunderground piping system.Micro-spray sprinklers are used toirrigate the plantation, but there isan offset of 35 feet from theproperty line where irrigationdoes not occur. In addition, theplantation is completely fencedand surrounded by signs warningintruders that treated effluent isbeing discharged.

The irrigation system can beshut down in five-acre blocks, pro-viding the capability for spot irriga-tion. The system is operated from amicrocomputer and requires onlyminimal daily input and supervision.

Should the plantation or apump fail, the treatment plant candischarge the effluent into a five-acre lagoon that it maintains foremergency storage.

“The system went in prettysmooth. There are just someminor changes I’d make when weexpand,” Stultz says. “Forinstance, some of our employeeshave a farming background, andthere are certain steps that wetried to get the engineers to dobefore planting the trees thatwould have been helpful. Thefield was plowed, leveled, andthen grass and a four-inch cuttingwere planted into the bareground. When we irrigated, wehad a weed control problem andhad to manually remove the grassfrom around the cuttings.

“What we recommended wasplanting grass seed on the site for ayear or two and spraying and har-vesting it for grass seed,” he says.“This would condition the soil, and

there wouldn’t be any weeds. Thenyou plant the trees in your streamlines and rows without disturbingthe soil. This way, grass is alreadygrowing and weeds aren’t a bigproblem.”

This natural system creates anattractive habitat for wildlife, pro-vides 30 to 50 percent more evapo-transpiration capacity than would adifferent crop of equal size, andprovides a new source of revenue.Trees can be harvested every sevento 12 years, and revenue from thesale of woodchips can be used tooffset a portion of the capital andoperation and maintenance costs ofthe system.

The city plans to expand thefacility every five years to matchpopulation growth. By 2020, thesite will cover 300 acres and willreuse five million gallons ofwastewater per day.

Reuse in HawaiiIn August 2000, the City of

Honolulu opened its first reusefacility on Oahu and, at 13 mil-lion gallons per day, it is thelargest in the Hawaiian Islands.The Honouliuli Water RecyclingFacility (HWRF) was built to pre-serve limited potable water and tosatisfy a 1990s decree mandatingthe city reduce the amount ofwastewater effluent it dischargesinto the Pacific Ocean.

Originally, the city entered intoa public/private partnership withUSFilter™ Operating Services, nowknown as Veolia Water. Accordingto the agreement, Veolia woulddesign, build, own, and operate thefacility for 20 years and then turn itover to the city.

One month before the facilityopened, however, the city decid-ed that the Honolulu Board ofWater Supply (HBWS) would pur-chase the HWRF and contract

Veolia Water to operate it. “Bybuying the facility, we’re in con-trol of the operation, and wereceive the profits by sort of tak-ing out the middle man profits,”Clifford Jamile, manager and chiefengineer of the Board of WaterSupply, reports in a July 2000Board of Water news release. “Wefeel the effects are twofold. One,we will save millions of gallons ofdrinking water per day currentlyused for irrigation or industrialpurposes. Two, the profits fromthe sale of reclaimed water addsanother revenue to our base, andwe can pass the savings on to thecustomer.”

The HWRF was built adjacentto the Honouliuli WastewaterTreatment Plant so that it could“T” into the plant’s effluent out-fall. The facility produces twogrades of high-quality recycledwater, R-1 water, which is usedfor landscape, agriculture, andgolf course irrigation, and reverseosmosis water (RO), which isused for industrial purposes, such as boiler feed water andultra-pure process water.

“When one of the industrialcustomers uses the RO water, theisland saves 600,000 gallons a dayof drinking water. With all theindustrial users combined, wesave about 2.5 million gallons aday of drinking water,” says KenWindram, project manager forVeolia Water.

Both types of recycled waterbegin with secondary treatedeffluent from the Honoluluwastewater treatment plant. The R-1 and the RO processesare shown in Figure 1.

Switching to RO water turnedinto a savings for industrial users.“When rain water filters through the lava structure in the ground, itpicks up between 60 to 70 parts

50 On Tap Winter 2005 BWS Water Reclamation Facility—Simplified Flow DiagramFIGURE 1

silica per million gallons in thedrinking water,” Windram says.“The silica turns into glass when itenters the boilers, costing thepower plants and refineries asubstantial sum of money to dem-ineralize the water to remove it.”

The HWRF, on the other hand,reduced the silica from 60 to 70parts per million to about 1 partper million gallons of water.“Industrial users had paid the cityand county $1.98 per thousandgallons for drinking water,” hesays. “In addition, they spent $5to $12 per thousand gallons todemineralize the water.

“We charge industrial usersabout $5 per thousand gallons forrecycled water,” Windram contin-ues, “yet they save between $2 and $7 per thousand gallons,depending on their daily flow rate, because ultra-pure RO waterallows more demineralizer produc-tion gallons between backwashes,greatly reducing the amount ofregeneration chemicals used.”

When the HWRF first opened,irrigation users such as golfcourses paid only 25 cents perthousand gallons of R-1 water.Over a three-year period, the ratewas increased to 65 cents.Providing water at such lowprices enticed users to replacegroundwater with recycled waterfor nonpotable uses. The R-1water users are pleased with theresults. Chlorides were reducedfrom 800 to 1,600 for groundwa-ter to less than 300 chlorides forrecycled water, and chloride sen-sitive vegetation is now plentifulon the golf courses.

“Because of the dissolved nitro-gen and phosphorus compoundsin the R-1 water, the golf courseshave reduced their purchases ofcommercial fertilizers, and the‘play’ on the courses has reallyimproved,” Windham says. “Also,when other Oahu golf courseshave to reduce water use duringthe summer season, the HWRF-watered golf courses continue toirrigate with the drought-proofrecycled water supply.”

The greatestobstacle to recycledwater was public accept-ance. “It’s simply a matterof explaining the technologythat is involved here and thestandards required by thedepartment of health beforewe can discharge the water,”Windram said.

Veolia Water and the HBWSdeveloped a public outreach pro-gram that educated the publicthrough facility tours, newsletters,brochures, and public presentationsat neighborhood board meetings,community meetings, church asso-ciations, and schools.

The Future of ReuseActions promoting wastewater

reuse are everywhere. New Jersey,for instance, has formed a ten-member commission to investigatewastewater reuse for non-potableurban uses such as irrigation, dustcontrol, and fire fighting.

Both New York and Louisianahave pending legislation dealingwith different aspects of reuse.And several cities—Odessa,Texas, and Denver, Colorado,among them—have started constructing resuse systems.

Wastewater reuse is a proventechnology that has been used formore than 40 years across theU.S. It is a drought-proof, renew-able supply of water that will helpcommunities keep water tablesfrom dropping, water resourcesfrom shrinking, and waterwaysfrom becoming polluted.

For More InformationThe National Environmental

Services Center (NESC) maintains

www.nesc.wvu.edu 51

a list of manufacturers and con-sultants in its Manufacturers andConsultants Database. The URL is:www.nesc. wvu.edu/nsfc_manufacturers.htm.

NESC also has products relatedto reuse. The Winter 1999 issue ofthe newsletter Pipeline (product #SFPLNL16) is devoted to the topic, asis the book Guidelines for WaterReuse (WWBKDM72). To ordereither of these products, call NESC at(800) 624-8301 or send an e-mailto info@mail.nesc.wvu.edu.

On the Internet, EPA Region 9 has some links to specific areasat www.epa.gov/region9/water/recycling. The WateReuse Assoc-iation has a Web site at www.watereuse.org.

A version of this article originallyappeared in the summer 2004 issueof Small Flows Quarterly (SFQ).Published by NESC, SFQ is a maga-zine devoted to small communitywastewater issues.

A member of NESC formore than eight years,Caigan McKenzie, hashad a number of herwater and wastewaterarticles reprinted in a variety of publications.