Winter 2000Vol. 11, No. 1

E

Small Community Wastewater Issues Explained to the Public

P i p e l i n evapotranspiration (ET) systems use an alternativeonsite treatment technologysuitable for areas where

risks of groundwater and surface watercontamination might exist.

E T systems employ the combinede ff e c t s of evaporation from soil andtranspiration from plants to dispose ofwastewater effluent. Wastewater flowsfrom a septic tank or aerobic unit intoa vegetation-covered distribution andstorage area. (See figure 1.)

From this storage area, moisture iswicked up to plant roots and to thesoil surface. The plants use the mois-ture in their growing processes andsubsequently transpire the excessthrough their leaves. Moisture thatmigrates up to the soil surface evapo-rates into the atmosphere as relativelyclean water.

These systems function mosteffectively in areas where annual

evapotranspiration rates exceedthe loading rate of the systemfrom rainfall and w a s t e w a t e r. In

other words,arid climates with minimalrainfall provide the best conditionsfor an ET system’s operation.

Individual dwellings, small housingclusters, and commercial or institutionalestablishments may find ET systemsappropriate to their sites. But larg es u r f a c e area requirements for distribu-t i o n /storage may make ET s y s t e m simpractical for bigger facilities.

Pretreatment adjustments to eff l u e n ta l s o may be necessary, depending onits source. Restaurants must have agrease trap installed, for example,before wastewater runs into a septicor aerobic tank for eventual ET d i s p e r s a l.

Two types of ETsystems are presentl yused. The lined ET system disposes o fwastewater without permitting eff l u e n tto move into the soil. The evapotran-s p i r a t i o n /absorption (ETA) system issimilar, but is c o ns t r u c t e d without aliner to permit a very slow rate of seep-age (absorption) into the ground.

This issue of Pipeline focuses onthese two versions of the ET system,how they are designed, how they treat

EVAPOTRANSPIRATION SYSTEMSIs an ET System Right forYour Site?Before deciding on buying property or build-ing a particular type of onsite watewatertreatment system, contact local health offi -cials to find out:

1)whether any onsite treatment system

is appropriate for that particular site,

2)minimum lot sizes and other site

conditions that dictate onsite systems,

3 ) how to apply for an onsite system permit,

4) the types of onsite systems allowed in

your area,

5) who may design, install, and inspect

onsite systems, and

6) who is responsible for maintaining

onsite systems, and what must be

done if a system malfunctions.

FIGURE 1 Evapotranspiration System

wastewater effluent, and what climateand soil situations warrant their use.Listed advantages and disadvantagesof ET systems demonstrate whetherthis type of wastewater treatmentworks for a particular site.

2PIPELINE — Winter 2000; Vol.11, No. 1 National Small Flows Clearinghouse (800) 624-8301

Why Use an ET System?

where soils are fairly impenetrable, butnot e n t i r e l y so. The ETAsystem dispos-e s of wastewater in the same e v a p o r a-t i o n /transpiration manner, but alsoallows e ff l u e n t to trickle slowly intothe underlying ground.

The loading rate for an ETA systemis generally more than that of an ETsystem in the same climate. And, anETA system can be used in a widerrange of climate conditions. As withany soil absorption system, the generalrule stands that wastewater must travelthrough two to four feet of unsaturatedsoil for adequate treatment beforereaching groundwater.

Design and ConstructionLittle has changed in basic ET s y s t e m

technology in the last 25 years, exceptfor regional adaptations. (See TexasDesigners . . . on page 6.)

The ET system needs to be located i na n area out of the way of runoff f r o ms t r u c t u r e s or sloped land and should b ebuilt on as level ground as p o s s i b l e . I fthe terrain is not level, terracing or con-crete retaining walls can be constructedto provide a suitably level distributionarea and to contain the system.

Household wastewater first collectsin a single- or double-compartmentseptic tank to separate solids from theeffluent. From the septic tank, thee ffluent flows into the distribution pipesof the water storage area of the system.

Two separate ET beds are recom-m e n d e d to prevent overloading thesystem. A v a l v e connects the two bedsand controls the flow. As one bedbecomes saturated, the eff l u e n t is

Factors that affect the performanceof the ET and ETA systems:

• Climate• Hydraulic loading• Sand capillary rise

characteristics• Depth of free water surface

in the bed• Cover soil and vegetation• Construction techniques• Salt accumulation (ET only)• Soil permeability (ETA only)

ET SYSTEMS

Very porous soils, like those composedof fill dirt, karst limestone, fracturedbedrock, or sites with a shallow watertable depth, make t r ad i t i o n a l a b s o r p t i o ns y s t e m s u n s u i t a b l e . E T systems are oneof a number of alternative t e c h n o l o g i e sa p p r op r i a t e for sites where e ff l u e n tcould quickly migrate to surface orgroundwater supplies. The lined ETsystem is also sometimes used to allowfor a closer proximity to water wells(50 feet) as opposed to the 100-f o o tsetback n e e d e d for soil absorptiond r a i n f i e l d s .

When deciding which system, theET or the ETA, might be better for asite, sites with a percolation rate ofless than five minutes per inch needto have the lined E T system i n s t a l l e d .If using a soils classification approachrather than percolation testing, a slowlypermeable soil (Class IV) would notrequire a liner unless seasonal ground-water tables are within two feet of theexcavation. Check local regulationsto be certain.

The ET system relies on the evapo-transpiration capabilities of the bed’ssurface and its plantings in that p a r-t i c u l a r environment. The impermeableliner covering the bottom and sides o f the distribution area contains theeffluent, storing it until it is absorbedup through the sand layer and intothe roots of plants growing on the

s u r f a c e of the bed.Several factors control the evapora-

tion rate in an area: precipitation, solarr a d i a t i o n , humidity, wind speed, andtemperature. Bright, hot sunlight causesevaporation of moisture. The dryinge ffect of regular, brisk winds alsoincreases transpiration in plants. Highhumidity, shading, and/or periods ofplentiful rainfall, on the other hand,l e s s e n the transpiration rate, makingan ET s y s t e m a poor choice in a climatewith those conditions.

So, a rapid exchange of moisturefrom the plants and soil surface to theair is key to successful operation ofthe ET system. Weather conditionschange on a daily, seasonal, or yearlybasis. These regional climate factorsmust be considered to insure ade-quate system performance. (See U.S.map on page 5.)

Use of the ET system might be fea-sible for summer homes in temperateregions with relatively dry summers.But long-term storage of effluent plusadditional water from rainfall, espe-cially during times of no net evapora-t i o n (high humidity or during rains),make the system unsuitable for year-round use in areas with frequent orheavy winter precipitation.

By the same token, the hydraulicl o a d i n g rate must also be consideredfor proper bed functioning. If too muchhousehold wastewater enters the sys-t e m , effluent may overflow, contami-nating groundwater; if not enough(the loading rate is too low), then thestanding water level may not be highenough to be effectively absorbedupward into the plants’ roots.

Building two beds helps alleviate thisproblem. One bed’s storage area fillsto capacity while the other bed rests.

ETA’s More VersatileDesign

An ETA system’s per-formance depends onboth soil characteristicsand climate c o n d i t i o n s .

This treatment system isu n l i n e d and designed for use

3PIPELINE — Winter 2000; Vol.11, No. 1 National Small Flows Clearinghouse (800) 624-8301

directed to the other bed. This strategyrequires occasional monitoring of thew a t e r level within the distribution sys-tem through the observation pipesinstalled down through the layers ofsoil, sand, and stone.

Sizing the ET DrainfieldThe amount of surface area needed

for the ET drainfield can be determinedusing this formula:

A=Q/ET-PrwhereA= total bed surface in square

feet (or square meters) Q= annual flow in cubic feet per

year (cubic meters/year) ET=annual potential evapotrans-

piration rate in feet per year (meters/year)

Pr= annual precipitation rate in feet per year (meters/year)

If using an ETA system, the formu-la adds a factor for the annual perco-lation rate (P) of the soil in feet peryear: A=Q/ET-Pr+P.

The Lining Makes the SystemThe impermeable liner containing

the ET system rests on two inches ofs a n d for stability and protection fromunderlying stone. (See figure 2.) Acushion layer of sand should also be

placed on top of the liner to preventpunctures from the rock media. Thisstep is vital to maintaining theintegrity of the liner.

A12-inch layer of uniformly sizedg r a v e l , ranging from three-quarters ofan inch to two-and-a-half inches indiameter, covers the bottom of thesystem. This gravel layer acts as thestorage area for the effluent. T h e b o t t o mof the storage area needs to be as l e v e las possible to assure even distributionof the water.

Distribution piping is positioned atthe surface of the gravel. These pipesshould be no more than 12 feet apartand no less than three feet from thewalls of the bed. Closer spacing ensuresthat the wastewater fills the entire stor-age area, making it readily available foruptake by the adjacent sand.

The sand extends down through thedepth of the gravel layer to the bottomof the ET bed. These sand extensions(called “wicks” by some installers)should be uniformly spaced through-out the bed between the rock-covereddistribution piping.

The effluent storage area (gravellayer) is covered with geotextile filterfabric, a water-permeable soil barrier,to prevent infiltration of sand into thegravel. A layer of sand 24 to 30 inch-es deep is then placed over the fabric

to within two inches of the top of theET bed. This sand must be fineenough to enable capillary action,d r a w i n g the effluent from the distri-bution area upward to the plant rootsnear the surface of the bed.

Monitoring pipes for periodicallyo b s e r v i n g water depth should be posi-tioned vertically down through thelayers of the bed to the base of thedistribution area. These pipes alsoprovide access in case emergencypumping becomes necessary.R e m o v a b l e covers on the pipe open-ings prevent accidents and keep i n s e c t sand rodents out of the system.

Surface Plants Finish the ProcessSandy loam is used to finish filling

the top two inches of the bed. T h ebed surface should be covered withthis rich soil mix and mounded fromthe center at a two to four percent gradeto encourage runoff of rainwater.

Plant vegetation that can withstand aw i d e range of soil moisture levels onthe surface of the bed. Maintain theplants in good health to maximize theirtranspiration capabilities.

Salts may build up in the soil ofthe bed as moisture evaporates. Saltsaccumulate most heavily during peri-o d s of dry weather, but are then redis-

Geotextile Fabric

Impermeable Liner

2” SandDistribution Pipe

FIGURE 2: Diagram of an ET System

Sand Layer

Gravel

ET SYSTEMS

Loam

Cover Plantingof grasses orshrubs

NOT TO SCALE

continued on page 4

Observation Pipe

4PIPELINE — Winter 2000; Vol.11, No. 1 National Small Flows Clearinghouse (800) 624-8301

Evapotranspiration Systems:Advantages and Disadvantages

Advantages• ET systems can be used where

physical and geological conditionsprohibit using subsurface wastewater disposal methods.

• Lined ET systems reduce or eliminate the risk of groundwater contamination.

• Costs for an ET system compare with other alternative onsite systems.

• ET can supplement absorption on sites with highly impermeable soils.

• E T systems provide a workablealternative in arid regions.

• ET systems may be appropriate for summer homes or recreation areas where evaporation and transpiration exceed rainfall.

• The system’s surface can be planted with shallow-rooted or na m e n t a l s to enhance the landscape.

Disadvantages• Climate conditions—precipitation,

windspeed, humidity, solar intensity,and temperature—determine the effectiveness of ET systems.

• The systems can’t be used where land is limited or the surface is highly irregular.

• Storage capacity is limited, so the system may not be able to hold- over winter wastewater for summerdisposal.

• Precipitation potentially may over-load the system.

• The bed liner must be watertight to prevent leakage into groundwater.

• Evapotranspiration must exceed rainfall by at least 24 inches for the system to be effective.

• Transpiration and evaporation rates decline in the winter when vegetation is dormant.

• Salt and the accumulation of otherelements may eventually be harmful to vegetation, thus dimin-ishing the effectiveness of the system.

overseeded to continue the transpira-tion process. Shallow-rooted ever-greens may also be planted on the ETsystem to provide a more attractivelandscape.

The most important considerationsin keeping an ET system functioningp r o p e r l y are selecting sand for theabsorption layer that provides maxi-mum capillary rise and installing aheavy liner of impervious rubber o rplastic at a thickness of 20 mils org r e a t e r. Reinforced concrete, gunite,or compacted and tested clay, one footthick or more, may also be used asliner material.

How much does an ET system cost? Determining the total costs for an

ET system depends on several fac-tors, such as the site, characteristicsof the wastewater, and the size andtype of facility from which thewastewater originates. The total sur-face area of the ET beds, which is afunction of the design loading rate,determines construction cost.

Further considerations include thetype and thickness of the systemliner, the availability of appropriatelyfine sand, whether retaining wallswill be needed, and the vegetationthat will be used to cover the surfaceof the beds.

Figures of approximately $10,000or higher are typical for a three-bed-room home’s septic tank and ETsystem.

continued from page 3

Maintenance of the ET system isminimal except for surface vegetation.The grasses or other plants growingon the beds need to be kept healthy,because they provide the vital step o ftranspiration in the disposal process.

Grass must be mowed regularlyto eliminate excess growth. But ifthe plants go dormant in the winter,s o m e other cool-season grass must beo v e r- seeded on the bed to ensure thesystem’s continued operation.

Excessive water from rain or

tributed throughout the bed withrainfall. Occasional monitoring f o re x c e s s i v e salts is necessary, since theses u b s t a n c e s may injure plant tissueover time. If injury is severe, thegrass (or other vegetative cover) mayneed to be re- placed with a more salttolerant species.

The ET bed should be planted witha vegetative cover that allows formaximum transpiration for theregion. Bermuda grass or St.Augustine grass placed over the soilas sod is most effective. Seedinggrass directly on the soil bed may beineffective if rainfall washes out themounded soil before the grass plantsbecome established. Larger plants thattolerate a broad range of moistureconditions and that have shallow rootsystems could also be used to fulfillthe evapotranspiration process.

Maintaining ET BedsThe ET system needs very little

routine maintenance. The septic tankshould be pumped out periodically,and the grass planted on the bedsshould be mowed regularly.

Since healthy vegetative growth i san integral part of this wastewater dis-p o s al system, the plants that facilitatethe evapo t ranspiration must continuallybe actively growing. If the grass orother vegetation goes through a win-ter dormancy period, an alternativecold-season grass cover needs to be

r u n o ff needs to be diverted around thesystem. Mounding the surface of thebeds helps prevent too much waterfrom entering the storage area andoverloading the system.

Salts accumulate in the ET systemand will be transferred into the growingvegetation on the surface. Salt-tolerantgrasses may offer a good choice forcover plantings, because some of thesalts will be removed from the sys-tem when the grass is mowed and theclippings are removed from the area.

ET SYSTEMS

Keeping Your ET System Working

55PIPELINE — Winter 2000; Vol.11, No. 1 National Small Flows Clearinghouse (800) 624-8301

An evapotranspiration system’sperformance depends on its pretreat-ment unit working properly.

Several back issues of Pipelinecontain useful information about thesiting, design, construction, installation,operation, and maintenance of septictanks and aerobic units, two commonpretreatment methods for ET s y s t e m s .

S u m m e r1 9 9 5 :“Septic Ta n k s’’P i p e l i n eItem #SFPLNL02

Fall 1995: “SepticTanks Operation andMaintenance’’P i p e l i n eItem # SFPLNL03

Winter 1996:“Aerobic TreatmentUnits’’ PipelineItem #SFPLNL04

Back issues of Pipeline may beordered from the National Small FlowsClearinghouse (NSFC) for $0.20 eachplus shipping and handling by calling(800) 624-8301 or (304) 293-4191,fax (304) 293-3161, or by e-mailingn s f c _ o rd e r s @ e s t d . w v u . e d u .

Please request each item by numberand title. Pipeline is also availableonline at NSFC's Website ath t t p : / / w w w. n s f c . w v u . e d u .

Septic Tanks NeedMaintenance Too

ET SYSTEMS

Light Blue - Minimal ET suitabilityMiddle Blue - More suitableDark Blue - Most suitable

Up-to-date information about con-structing an evapotranspiration systemmay be found at a number of siteson the World Wide Web. Questionsmay also be posted on the waste-water forum, “Septic Talk,’’ hostedby Texas A&M University on issuesconcerning ET systems or otheralternative treatment methods.

Austin City Connectionh t t p : / / w w w. c i . a u s t i n . t x . u s / w r i / d i s 2 . h t m

Texas A&M Un iversity Extension Servicehttp://agpublications.tamu.edu/pubs/e8.pdf

Texas On-Site WastewaterTreatment Research Councilhttp://towtrc.tamu.edu/

National Onsite WastewaterRecycling Association’s OnsiteInsight Newsletterhttp://nowra.org/news/news.shtml

U.S. Environmental Protection AgencyThe EPAhas a design manual of onsitewastewater treatment and disposalsystems on the Web with a listing forevapotranspiration systems. The infor-mation is listed in the contents asbeginning on page 300 of the docu-ment. To read or download that portionof the EPA document, type in page318 in the “Go To’’page space.http://www.epa.gov/cgi-bin/claritgw

ET System Information on the Internet

Regions Appropriate for Evapotranspiration SystemsColored areas represent climates most suitable for ET systems.

6PIPELINE — Winter 2000; Vol.11, No. 1 National Small Flows Clearinghouse (800) 624-8301

SPRAY & DRIP IRRIGATION

Texas Designers Alter ET Systems to Suit Their Needs

The Texas Water Commission( T W C ) found that previously approveds i z i n g methods for evapotranspira-tion beds caused frequent system fail-ures in that state. New formulas differin that (1) they consider site specificdata for evaporation and rainfall forthe different regional climatesof Te x a s ,and (2) they incorporate spec i f i cinformation about the amount ofwastewater generated from differentsized houses and other facilities usingET technology.

The old method had separate for-mulas for single family residencesand multiple family residences. T h ecalculations were based on a standardsized area and the number of bedroomsdivided by the mean overall evapora-tion rate and the rainfall rate.

The new recommendations use oneformula for both individual homes,apartments and condominiums,restaurants, parks, and other areas.The formula is based on the estimat-ed daily amount of wastewater gen-

erated in gallons per day and the netlocal evapotranspiration rate.

Similar to the previously men-tioned formula A=Q/ET-Pr (see page3), the TWC’s recommendationincludes a conversion factor of 1.6(12 inches/foot divided by 7.48 gal-lons/cubic foot) making the formulaA=1.6Q/ET-Pr.

Wastewater treatment systembuilders in Texas also found slightalterations to the basic ET systemdesign appropriate for conditions there.The use of pure sand for the absorp-tion layer has been exchanged in favorof a loamy soil/sand mix. Professionalsthere say that the absorption rate theyget with this mix surpasses that of astraight sand layer.

Similarly, the wicks that run fromthe bottom of the rock media layerup to the soil/sand layer are made ofloamy soil also.

ET systems in some parts of Texasare also being built with a greaternumber of distribution pipes laid in

the beds to increase the dispersal ofthe effluent throughout the system.Piping is laid two feet from the wallsand four feet apart instead of up to12 feet apart.

Other kinds of media, like tirechips, are being used for the rocklayer; and storage systems, such asleaching chambers (placed on four-foot centers and covered with loamysoil), have been found to provideeffective storage for effluent.

The TWC recommends that oneET bed be open and the other closedand the flows alternated on a monthlybasis so that one bed is always dryand rested. During wet weather, bothbeds should be opened to maximizeevapotranspiration.

From the Texas WaterCommissionNet evaporation rates for variousareas of Texas demonstrate thatthe central and western part of thestate have climates most condusiveto using ET systems.

Area Net Evaporation (inches per day)Amarillo 0.19 Austin 0.10Beaumont 0.00Big Spring 0.17Brownsville 0.08Chillicothe-Vernon 0.12Daingerfield 0.08Dallas 0.13El Paso 0.27Fort Stockton 0.26Houston 0.00Lake Somerville 0.09Laredo 0.24Lubbock 0.19Nacogdoches 0.00San Antonio 0.10San Angelo 0.25Temple 0.09

ET beds in sensitive environments ensure wastewater contaminants do not reach water supplies.This inspector for the Lower Colorado River Authority in Austin, Texas, inspects sand thicknessbefore the system liner is installed.

ET SYSTEMS

Photo courtesy of Bruce Lesikar, Texas A&M

Some information for this article was providedby the Texas Water Commission, Austin, Texas.

7PIPELINE — Winter 2000; Vol.11, No. 1 National Small Flows Clearinghouse (800) 624-8301

C O N T A C T SNational Small FlowsClearinghouse (NSFC)The NSFC offers a variety of technicalassistance and free and low-cost informationand materials about wastewater technolo-gies for small communities. Just a few ofthe NSFC’s many resources and servicesare mentioned in this newsletter. Call theNSFC at (800) 624-8301 or (304) 293-4191or visit our Web site at www.nsfc.wvu.edufor more information.

Extension Service OfficesLand grant universities have U.S.Department of Agriculture (USDA)Extension Service offices on campus and inother locations that provide many servicesand assistance to small communities. Forthe number of the extension office in yourarea, check the government pages of yourlocal phone directory, contact the NSFC atthe number listed above, or call the USDAd i r e c t l y at (202) 720-3377.

State and Local HealthDepartmentsHomeowners and residents of small com-munities interested in evapotranspiration sys-t e m s and other wastewater systems shouldc o n t a c t their state or local health depart-ment for more information about regulationsand requirements. These agencies are usu-ally listed in the government section of localphone directories.

Rural Community AssistanceProgram (RCAP)RCAP is a network of nonprofit organiza-tions that provides assistance to rural andl o w - i n c o m e communities concerning mostaspects of planning wastewater projects.Call RCAP’s national office at (703) 771-8636,visit their Web site at www.rcap.org, or callthe NSFC for the number of your regionalRCAP office.

People in small towns and ruralareas sometimes have difficulty find-i n g out about onsite treatmentt e c h n o l o g i e s and relevantsolutions for their probl e m s . If theneed for a new wastewater s y s t e marises—or if existing problems n e e dto be fixed—where can folks go forhelp?

The National Small Flows Clearing-h o u s e (NSFC), sponsored by theU.S. E n v i r o n m e n t a l ProtectionAgency, offers personal t e c h n i c a lassistance, as well as many items t h a tare available from their products catalog.

N o w, the NSFC is asking for yourhelp. The EPA’s National OnsiteD e monstration Program (NODP)Phase II is working to acquire infor-mation for a new database they areputting together. The DemonstrationProjects Database will be a compila-tion of domestic onsite wastewaterdemonstration projects.

The NODP is interested in acquir-ing information from you aboutinnovative and alternative onsite ands m a l l community wastewater treat-ment/disposal technologies used insites having geographic limitations,environmental sensitivity, or otherspecial needs.

Information forthe database willinclude:

✓ project objective(s),

✓ contacts,

✓ funding source(s) and partnerships,

✓ site location(s) and conditions,

✓ demonstrated technologies, and

✓ monitoring information (if available).

Once the NODPhas developed thed a t abase into a viable resource, theNSFC can be contacted and their staffwill develop reports pertinent to theneeds of thecustomer.

These reports will include informa-t i o n about the overall project and spe-c i f i c information about each individualproject, such as contacts, demonstratedtechnologies, site conditions, and g e n e r a lsystem information.

If you are an owner, operator, manag-e r, regulator, researcher, or are in anyway involved with a domestic waste-water demonstration project, you canhelp others meet their wastewater treat-ment needs. The NODP has created ani n f o r m a t i o n collection form that maybe mailed to you, downloaded, orcompleted online.

Call the NODP for more informa-tion about contributing to the data-base at (800) 624-8301 or (304) 293-4 1 9 1 or visit our Web site atw w w. e s t d . w v u . e d u /NSFC_NODPoverview.html.

NODP Needs Your InputHelp Build the New Demonstration Projects Database

ET SYSTEMS

Please feel free to reprint thisissue or any P i p e l i n e articles inflyers, newspapers, n e w s l e t t e r s ,or educational presentat i o n s .We just ask that you include thename and phone number of theN a t i o n a l Small FlowsClearinghouse (NSFC) on thereprinted information, and sendus a copy for our archives.

n a t i o n a l o n s i t e d e m o n s t r a t i o n p r o g r a m

SPRAY & DRIP IRRIGATION

PIPELINE — Winter 2000; Vol.11, No. 1 National Small Flows Clearinghouse (800) 624-8301

8

RESOURCES AVAILABLE FROM NSFC

For wa s te wa ter information, call the NSFC at (800) 624-8301 or (304) 293-4191

PIPELINE

Pipeline is published quarterly by the National SmallFlows Clearinghouse at West Virginia University,

P.O. Box 6064, Morgantown, WV 26506-6064

Pipeline is funded through a grant from theU.S. Environmental Protection Agency

Washington D.C.Steve Hogye—Project Officer

Municipal Support DivisionOffice of Wastewater Management

National Small Flows ClearinghouseWest Virginia University

Morgantown,WVPeter Casey—Program Coordinator

Michelle Moore—Writer/EditorMichelle Sanders—Graphic Designer

Tricia Angoli—Technical Advisor

Permission to quote from or reproduce articles in this publication is granted when due acknowledgement is

given. Please send a copy of the publication in which informa-tion was used to the Pipeline editor at the address above.

ISSN 1060-0043

The contents of this newsletter do not necessarily reflect the views and

policies of the Environmental Protection Agency, nor does the mention

of trade names or commercial products constitute endorsement or

recommendation for use.Printed on recycled paper

an equal opportunity/affirmative actioninstitution

To order any of the following avail -a b l e p roducts, call the National SmallF l o w s Clearinghouse (NSFC) at(800) 624-8301 or (304) 293-4191,fax (304) 293-3161, e-mailn s f c _ o r d e r s @ e s t d . w v u . e d u , or writeNSFC, West Virginia University, P.O.Box 6064, Morgantown, WV 26506-6064. Please request each item bynumber and title. A shipping andhandling charge will apply.

Fact Sheet: Evapotranspiration SystemsNSFC offers two fact sheets on evapo-transpiration systems. One presents ageneral overview of the ET system ofwastewater treatment and disposal,and the other goes into more technicaldetail. Criteria for building ET s y s t e m sare described, advantages and disad-vantages are listed, and basic designand construction are outlined.References used to develop the factsheet are included for further infor-mation. The fact sheets are free. General overview: Item #WWFSGN11 0Technical overview: Item #WWFSOM32

Evapotranspiration andEvapotranspiration/Absorption SystemsDesign ManualThis design manual describes the

development and use of ET and ETAsystems in the U.S. General designconsiderations, such as required surfacearea, system depth, distribution netw o r k ,surface cover, vegetation, siting, andconstruction materials, also are dis-c u s s e d . The manual costs $2.30.Item #WWBLDM04

Small Wastewater Systems: AlternativeSystems for Small Communities and RuralAreasThis eight-page booklet providesdescriptions of the various alternativewastewater systems available to smalland rural communities. The bookletis free. Item #WWPSPE002

Onsite Wastewater Treatment andDisposal SystemsPublished by the U.S. EnvironmentalProtection A g e n c y, this 410-page designmanual contains important technicalinformation about several onsitetechnologies, including sand filtersand soil absorption fields. The priceis $45. Item #WWBKDM35

NSFC Products GuideNSFC Products Guide lists anddescribes the many products andservices that the NSFC offers. Thecatalog may also be downloaded

from the NSFC Web site athttp://www.nsfc.wvu.edu, or it isavailable free upon request. Item #WWCAT