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Technology review of urine diversion componentsOverview of urine diversion components such as waterless urinals, urine diversion toilets, urine storage and reuse systems
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Published by:Deutsche Gesellschaft fürInternationale Zusammenarbeit (GIZ) GmbH
Sustainable sanitation - ecosan program
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Place and date of publication:Eschborn, May 2011
Authors:Dr. Elisabeth von Münch, Dr.-Ing. Martina Winker
Responsible editor:Dr. Elisabeth von Münch
Acknowledgement:Nathasith Chiarawatchai, Florian Klingel, Christine Werner and Patrick Bracken (authors of an earlier version), Dr. Håkan Jönsson, Dr. Elisabeth Kvarnström and Dr. Arno Rosemarin (reviewers of the current document)
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Photos:Cover: © Philipp Feiereisen, Steffen Blume, Lukas Ulrich, Abdoulaye Fall, Sören Rüd, Robert Gensch, iStockBack: © GIZ, Steffen Blume, Elmer Sayre, Sören Rüd, Patrick Zimmerer, Alexandra Höhne/Rwanda Village Concept Project, Elisabeth von Münch, Stefanie LorenzInside: © Elke Mühlegger/EcoSan Club Austria, Patrick Zimmerer, Philipp Feiereisen, Julia Littmann, Håkan Jönsson, Abdoulaye Fall, Steffen Blume, Philipp Feiereisen, Robert Gensch, Heike Hoffmann, Arne Panesar, Michael Kropac
Technology review of urine diversion componentsOverview of urine diversion components such as waterless urinals, urine diversion toilets, urine storage and reuse systems
5 Foreword
ThispublicationisanimportantcontributionoftheGIZprogram“Sustainablesanitation–ecosan”asitpullstogetherscatteredknowledgearoundthetopicofurinediversioninaconcisemanner.
TheprogramiscommissionedbytheGermanFederalMinis-tryforEconomicCooperationandDevelopment(BMZ).Theecologicalsanitation(ecosan)approachisabletoaddressboth:childhealthwhichneedstobeimprovedthroughbettersani-tation,andsustainablemanagementandsaferecyclingofimportantresourcessuchaswaterandnutrients,inparticularphosphorus.
Itisapositivedevelopmentthatmoreandmorepeoplearenowbecomingawareofthepresentworldwidesanitationcrisis–whichiskillingthousandsofyoungchildreneachday.Itisalsobecomingmorewidelyknownthatphosphorus(intheformofphosphaterockdeposits),isanon-renewable,limitedresource.High-qualityphosphaterockwillrunoutinthefuture.
Thesafeuseofurineasafertilisercanenableallfarmerstogrowmorefood–notonlythosewhohavethemeanstobuyartificialfertilisers.Whenpricesforartificialfertiliserincreaseagain–asin2008whenpricesincreasedbyuptoeighttimesinsomecountries–farmersrelyingonurinewillbelessaffectedbysuchfertiliserpricehikes.
Iamsurethistechnologyreviewwillhelpandinspirepeopleworkingonsustainablesolutionsforexcretamanagement.Feedbackaboutthispublicationiswelcomeandshouldbesenttoecosan@giz.de.
Letusjointlycontinuetoworktowardstheaimofsafeandsustainablesanitationforall!
Andreas KanzlerHead of Water SectionDivision Water, Energy, Transport
DeutscheGesellschaftfürInternationaleZusammenarbeit(GIZ)GmbHEschborn,Germany
Eschborn,May2011
6 Contents
1 Summary .......................................................................................... 8
2 Introduction to urine diversion (UD) ................................... 8
2.1 DefinitionofUD.................................................... 82.2 PurposesofUDinstallations.................................. 92.3 BenefitsofUDsystems........................................... 92.3.1BenefitsofalltypesofUDtoiletsand waterlessurinals...................................................... 92.3.2FurtheradditionalbenefitsofUDDTscompared
topitlatrines...........................................................92.4 ChallengeswithUDsystems.................................. 102.4.1Socialacceptanceamongstusers............................. 102.4.2Usercooperation..................................................... 102.4.3Urinereuse/disposalissues...................................... 102.4.4Urineprecipitation.................................................. 10
2.5 Quantityofurine................................................... 112.6 Qualityofurine...................................................... 112.6.1Sourceconsiderations............................................. 112.6.2Pathogens................................................................ 112.6.3Nutrients................................................................ 112.6.4Micro-pollutants..................................................... 12
2.7 Urinetreatment...................................................... 122.7.1 Treatmentobjectives............................................... 122.7.2 Treatmentbystorage.............................................. 122.7.3 Otherurinetreatmenttechnologies........................ 12
2.8 AreUDsystemsmorecosteffective?...................... 132.9 TechnicalcomponentsusedforachievingUD....... 13
3 Reuse of urine as fertiliser in agriculture ....................... 13
3.1 Howtouseurineasafertiliser............................... 133.1.1 Basicguidelines...................................................... 133.1.2 Specificadvantagesofurinecompared
toothermineralfertilisers.................................... ..143.1.3 Disadvantagesofurinecompared
toothermineralfertilisers.................................... ..143.1.4 Shouldurinebeappliedundiluted
ordilutedwithwater?........................................... ..153.2 Arehormonesandpharmaceutical
residuesinurineproblematicforreuse?.................. 153.3 Isurinean“organic fertiliser”
andcanitbeusedinorganicfarming?................... 16
4 Waterless urinals ........................................................................ 16
4.1 Definitionandpurpose..............................................164.2 Historicaldevelopmentofwaterlessurinals............ 174.3 Odourcontrolmethods(general)........................... 174.4 Odourcontrolforconnectionofurinal
tosewerorstoragetank.......................................... 174.4.1Rubbertubeseal..................................................... 174.4.2Curtainvalveseal.................................................. 174.4.3Sealantliquid(blockingfluid)................................ 184.4.4Othermethodsfortheodourseal.......................... 19
4.5 Furtherdesigninformation.................................... 194.6 Useandmaintenanceofwaterlessurinals............... 194.7 Useracceptanceofwaterlessurinals....................... 204.8 Suppliersandcostsofwaterlessurinals................... 204.9 Howtochoosetherighttypeofwaterlessurinal.... 20
5 Urine diversion toilets .............................................................. 21
5.1 Definition............................................................... 215.2 BasicdesigninformationforUDtoilets................. 215.3 Urinediversiondehydrationtoilets(UDDTs)........ 215.3.1 Basicdesigninformation........................................ 215.3.2Odourcontrolforurinecollectionsystem.............. 225.3.3Constructionmethodsandmaterials...................... 225.3.4Useandmaintenance.............................................. 225.3.5 Projectexamples..................................................... 22
5.4 UDflushtoilets...................................................... 225.4.1 Overviewonhistoricaldevelopment....................... 225.4.2Basicdesigninformation........................................ 225.4.3Odourcontrolfortheurinecollectionsystem........ 235.4.4Materials................................................................. 235.4.5 Useandmaintenance.............................................. 235.4.6Projectexamples..................................................... 23
5.5 SuppliersandcostsforUDtoilets.......................... 235.6 HowtochoosebetweenaUDDT
andaUDflushtoilet.............................................. 23
6 Urine piping and storage tanks ............................................. 24
6.1 Urinepiping........................................................... 246.1.1 Functionalprinciples.............................................. 246.1.2 Materials................................................................. 246.1.3 Pipesizeandlayout................................................ 246.1.4 Odourcontrol......................................................... 24
6.2 Urinestoragetanks................................................. 246.2.1Functionalprinciples.............................................. 246.2.2Locations................................................................ 256.2.3Materials................................................................. 256.2.4Urinetanksize....................................................... 256.2.5Numberofurinetanksneeded............................... 256.2.6Urineoverflowpipe................................................ 266.2.7Examples................................................................ 26
6.3 Ventilationforpressureequalisationofpipesandtanks................................................... 26
6.4 Maintenanceofurinepipesandtanks.................... 27
7 References ....................................................................................... 27
7.1 Referencesusedinthisdocument.......................... 277.2 Videoclips.............................................................. 297.3 Additionalphotos................................................... 29
8 Appendix: Worldwide listing of suppliers for waterless urinals, UD pedestals and squatting pans ....................................... 29
7 List of Tables & Figures:
Table 1.Averagechemicalcompositionoffreshurine(literaturevalues)andstoredurine(simulatedvalues,seeUdertetal.(2006))...................................................... 12
Figure 1.Waterlessurinalsformen.Left:CentaurusmodelofKeramagcompany.Right:PlasticurinalfromAddicom,SouthAfrica,withEco-Smellstopdevice(sources:left:E.v.Münch,Delft,2006;right:Addicom)............................................ 16
Figure 2.Twotypesofodoursealsforwaterlessurinals.Left:Flatrubbertube(KeramagCentaurus).Right:(leftside)See-throughpipefitting;(rightside)see-throughEcoSmellstop(ESS)unitshowingthebluesiliconcurtainone-wayvalveinside(source:(left):E.v.Münch,2007;right:Addicom).......... 18
Figure 3.EcoSmellstop(ESS)unitwithpipefittingandextractor.InsidetheESSisthesiliconcurtainvalve(source:Addicom)..................................................... 18
Figure 4.Exampleinstructionsheet,showingreplacementofsealantliquidforUridanurinals(otherurinalswithsealantliquidhaveasimilarmaintenanceroutine)(source:Uridan).............................. 18
Figure 5. Left:IndoorUDDT(pedestaltype)inJohannes-burg,SouthAfricainthehouseofRichardHolden(source:E.v.Münch,2006).Right:UDDTsquattingpaninBanga-lore,India,withthreeholes:theareainthefrontisforanalwashing,middleisforfaecesandbackisforurine(source:D.Schäfer,2008)............................................................... 22
Figure 6.UDflushtoilets.Left:Gustavsberg(inMeppel,theNetherlands);Right:Dubbletten(inStockholm,Sweden),(sources:E.v.Münch,2007)..... 23
Figure 7.Left:Low-costsolution:20LplasticjerrycanforurinestorageatindividualtoiletlevelinOuagadougou,BurkinaFaso(source:E.v.Münch,2006)Right: Below-groundplasticurinestoragetanksatKullön,Swedenduringtheconstructionprocess.Thetankswillbecoveredwithsoil(photo:MatsJohansson,source:Kvarnströmetal.,2006)............. 26
Figure 8.Urinestoragetankmadeofa150m³plasticbladderatLakeBornsjönnearStockholm,Sweden(photocomissionedby:E.v.Münch,2007)......... 26
Figure 9. PlasticurinestoragetankinOuagadougou,BurkinaFasoaspartoftheEU-fundedprojectECOSAN_UEledbyCREPA(source:S.Rüd,2008)............................... 26
8 1 Summary
Thetargetaudienceforthispublicationarepeoplewhoarenewtothetopicofurinediversionornewtothetopicofecologicalsanitation(ecosan),andwho:ÿ needtoobtainanoverviewofthemainissuesfor
urinediversionandthemaintechnicalcomponentsÿ wanttoknowwhicharethemainimportantdocu-
mentsforfurtherreadingÿ haveaparticularinterestindevelopingcountries,
withapro-poorperspectiveÿ needinformationonavailablesuppliersworldwide
andoncostsforwaterlessurinalsandurinediversiontoiletpedestalsandsquattingpans.
Thispublicationexplainsthepurposesofurinediversion,itsbenefitsandchallenges,urineprecipitation,urinetreatmentandreuseinagriculture.Itprovidesanoverviewondesignandoperationalaspectsforequipmentneeded,suchaswaterlessurinalsandurinediversiontoiletsincludingsupplierinforma-tionandindicativecosts.Thepublicationalsoprovidesbasicdesigninformationforurinepipingandstoragetanks(inclu-dingtanksizing,odourcontrolandventilationdesignissues).
Urinediversionisthetermusedtodescribekeepingurineandfaecesseparatefromeachotheratthepointofexcretion.Thefourmainpurposesofimplementingsystemswithurinediver-sion(UD)are:toreduceodour,topreventproductionofwetfaecalsludge,toreducewaterconsumptionandtocollectpureurineforuseasfertiliserinagriculture.
Furtherbenefitsincludeminimisedexcreta-relatedgroundwaterpollution,thefactthatthetoiletcanbeindoors(asopposedtoapitlatrine)andbettercontrolovermicro-pollutantsdis-chargedtotheenvironment.Thechallengesincludesocialacceptance,usercooperation,urinereuseordisposalissuesandurineprecipitation.
Equipmentusedinurinediversionsystemsincludeswaterlessurinals,urinediversiontoilets(eitherwithorwithoutflushwater),urinepipingandurinestoragetanks.Themostcom-monandcheapestmethodtotreaturineforpathogenremovalfromfaecalcross-contaminationisbyextendedstorage.
Urinecansafelybeusedingardeningandagricultureasanutrient-richfertiliser,providedrelevantreuseguidelines(seeWHO,2006)arefollowed.Ifthereisnousefortheurine,itcanbedischargedtoasewerorpossiblyinfiltratedintheground(iflocalsoilandgroundwaterconditionspermitthiswithoutadverseimpactsongroundwaterquality).
Waterlessurinalsenablethecollectionofundilutedurineandarealreadywidelyusedinmanyindustrialisedcountries(par-ticularlyinGermany)inpublicorcommunalbuildings(not
commonathouseholdlevel).Butsofar,theyareusuallyjustconnectedtothesewersystemandtheurineisneithercollectednorreused.Odourcontrolinwaterlessurinalsiscrucialforuseracceptance,andisachievedby(i)variousdesignsforanodourblockingmechanism(mostnotablywithaflatrubbertube,siliconcurtainvalveorsealantliquid),and(ii)byen-suringcorrectmaintenanceprocedures.
Urinediversiondehydrationtoilets(UDDTs)collectfaeces“in a dry system”(i.e.separatelyfromurine,flushwaterandanalwashwater)invaultsorbucketslocatedunderneaththeUDpedestalorsquattingpan.Forpro-poorapproachesindeve-lopingcountries,UDDTsaremoresuitablethanUDflushtoilets,asthelatterstillrequireasewersystemandtreatmentforbrownwater.UDDTscaneasilybedesignedtosuituserswhousewaterinsteadoftoiletpaperbyprovidingaseparatedrainholeforanalwashwater.
Odourcontrolandpressureequalisationwithinurinepipesandurinestoragetanksneedtobeincludedinthedesigninthecaseofindoormulti-toiletsystems.WaterlessurinalsandUDDTsareapromisingstepforwardtowardsimplementingwatersa-ving,moresustainablesanitationandreduceddependencyoncostlyartificialfertiliser,thuscontributingtopovertyreduction.
2 Introduction to urine diversion (UD)
2.1 Definition of UD
Urinediversion(UD)devicescollecturineseparatelyfromfaecesandfromwater(orwithminimalflushwater).Aurinediversiontoilethastwooutletswithtwocollectionsystems:oneforurineandoneforfaeces(andpossiblyathirdoneforanalwashwater),inordertokeepthesetwo(orthree)excretaorwastewaterfractionsseparate.UDtoiletsmay,ormaynot,mixwaterandfaeces,orsomewaterandurine,buttheynever mix urine and faeces.Section 5.1providesanoverviewofthetwomaintypesofurinediversiontoilets:UDtoiletswithoutflushwater(thesearecalledurinediversiondehydrationtoiletsorUDDTs)andthosewithflushwater(UDflushtoilets).
Urinals–widelyusedbymenatpublictoilets,restaurants,schools,etc.–workasurinediversiondevicesbecauseurineiscollectedseparatelyfromfaeces.Whenurinalsareofthewaterlesstype,theycancollecttheurinepure,meaningwithoutdilutionwithwater.
Urinediversionmaybeusedinecologicalsanitation(ecosan)concepts,butnot all ecosan projects use urine diversion.Ecosanisanapproachtosanitationwhichfocussesonreuseofnutrientsandorganicmattercontainedinexcretaandwastewater,andemphasisessustainabilityinallaspects1.
1 Thedefinitionof“sustainable sanitation”isprovidedinthefirstvisiondocumentoftheSustainableSanitationAlliance(http://www.susana.org/index.php/lang-en/intro/vision/42-vision/76-vision-document).
9 2.2 Purposes of UD installations
ThepurposeofaUDinstallationisusuallyone,orseveralofthefollowingfourpurposes–whichcanbesplitintwocategories:
Purposes relevant for all types of UD systems (describedinmoredetailinSection 2.3.1below):1. toreducewaterconsumption2. tobeabletocollecturinepureandundilutedso
thatitcan–aftersanitisationbystorage–besafelyusedasfertiliserinagriculture.
Purposes relevant for UDDTs (urinediversiondehydrationtoilets)comparedtopitlatrines(describedinmoredetailinSection 2.3.2below):3. toreduceodour4. toavoidproductionofwet,odorousfaecalsludge,
whichhastoberemovedbysomeonewhenthepitlatrineisfull.
2.3 Benefits of UD systems2.3.1 Benefits of all types of UD toilets and waterless urinals
ÿ Water savings: UDDTsandwaterlessurinalsrequirenoflushwater,whereasconventionalurinalsusearound4Lperflush(flushtoiletsuseabout8-12Lperflush;pourflushtoiletsuse2-3Lperflush).UDflushtoiletscanalsoreducewaterconsumptionwhencomparedtoconventionalwater-flushedtoilets:thisisbecausethe“urine flush”usesalowvolumetoflushawayremai-ningurinedropsandusedtoiletpaper(0.5to2Lofflushwater,dependingonthetoiletmodel).Ifurine-soiledtoiletpaperiscollectedinabin,ratherthanflushedaway,watersavingscouldbeevengreater.
ÿ Thecollectedurinecanbeusedasfertiliser,whichcanincreasecropyields.AsexplainedfurtherinSection 3,urineisaliquidfertiliserrichinnitrogenandphosphorus.Thisisofparticularimportanceforthosefarmersindevelopingcountrieswhocannotaffordmineralfertilisers.
ÿ Recycling of phosphorus from urinemaybecomenecessaryinthemid-termfutureandiseasiertoachieveifurineiscollectedpureratherthanmixedwithwastewater.Phosphorusisanessentialelementforagriculturalproduction.Itiseitheravailableinthesoiloraddedwithfertiliser,andisproducedfrommineddepositsofphosphaterock.High-gradephosphaterockreservesarerunningout:atcurrentratesofexploitation(increasingataround3%peryear),theeconomicre-servesofphosphoruswilllastnomorethan50years.TheeconomicallyviablereservesintheUnitedStatesforexample,willbedepletedwithin25to30years(Rosemarinetal.,2008;Cordelletal.,2009).Inthe
future,increasedeffortstorecyclethephosphoruscontentofhumanandanimalexcretaareinevitable(EcoSanRes,2008).
ÿ Ifthereisconcernabouthormones and pharmaceuti-calresiduesenteringdrinkingwatersourcesviahouse-holdwastewater(sewage),thentheseparatecollectionofurinecansimplifyremovalofthesesubstancesfromtheenvironment.Particularlyforindustrialisedcoun-tries,thiscouldbeamajordrivingforceinfavourofUDsystems(see Section 3.2).
ÿ Urinediversionmayalsocreatebusiness opportunities fortheprivatesectorviathesaleofUDtechnologyandrelatedservices.
ÿ Inmanycases,cost savingscanberealisedwhenim-plementingUDsystemsespeciallyregardingeconomiccostswhenasystem-wideanalysisisperformed(inclu-dingexternalcostsduetogroundwaterpollutionforexample),seeSection 2.8fordetails.
2.3.2 Further additional benefits of UDDTs compared to pit latrines
ÿ Thereissignificantlyless odourwhenurineandfaecesarenotmixed–asinaUDDT–comparedtothecasewhereurineandfaecesaremixedasinapitlatrine.
ÿ SinceUDDTsareodour-freewhendesignedandoper-atedcorrectlyandsincetheydonotneedcontactwiththesoiltoinfiltrateliquids,UDDTscanbeindoors,whichleadstoimprovedsecurity,privacyandusercomfort.Thisaspectisveryimportantespeciallyforwomenandgirls,forwhomitmaybetoodangeroustogotothetoiletoutsideindarkness(sexualassaults).
ÿ No production of wet faecal sludge:Faecescollectedinadrymanner,separatelyfromurineandwater,arenotoffensive,especiallyafteranextendeddryingperiod.Hence,itismucheasiertoemptythefaecesvaultofaUDDTthanthepitofapitlatrine.Thisisparticularlyimportantforhillyorcrowdedareaswhereaccesstopitlatrinesbyconventionaltrucksisimpossible.
ÿ Minimised toilet-related groundwater pollution with nitrate and pathogens.Pitlatrinesandseptictanksaredesignedtoinfiltrateliquidintothesoil,whichcanleadtogroundwaterpollutionifthepopulationdensityishigh,thegroundwaterlevelishighortherearepre-ferentialpathwaysinthesoiltothegroundwater.UDDTsontheotherhandcollecttheurineandfaecesabove-groundandthereforedonotpollutetheground-water.Notethatonsitegreywaterdisposalcanalsoleadtogroundwaterpollutionandthisissueisnotaddressedbyurinediversiontoilets.
1010 2.4 Challenges with UD systems2.4.1 Social acceptance amongst users
Regardingsocialacceptance,thesuccessfuladoptionofurinediversionsystemsiscloselylinkedto:ÿ Users'motivationandwillingnesstochangeexisting
habitsandbehaviours,forexample: „ Thewillingnessofmentositdownonpedestal-type
UDtoiletsforurinationifnourinalsarebeingprovi-ded–thisdoesnotapplytosquatting-typeUDtoilets;
„ ThewillingnesstomovebackwardsalittlebitsothatanalwashwatercanbecollectedseparatelyfromfaecesinthecaseofUDDTsand“anal washers”.
ÿ Supportiveattitudeofallstakeholdersinvolved(users,maintenancestaff,planners,farmers,politiciansandsoon).
ÿ Possibleuseofurineasafertiliser(orsomeotherdisposaloptionforcollectedurineifreuseinagricultureoraquacultureisnotpossible).
ÿ Culturalobstacleslikesuperstitionoftheusers.
Odournuisance(beitonlyperceivedoractual)isafurtherpotentialobstacletosocialacceptance,butwiththecorrectdesignandoperation,odoursfromwaterlessurinalsandUDtoiletsarethesameorlessthanconventionalurinalsandtoilets.Also,UDDTshavesignificantlylessodourandfliesthanpitlatrines,andcanthereforebeplacedindoorswhichmayprovetobeasignificantdriverforsocialacceptance.
Socialacceptancealsodependstoahighdegreeon:ÿ Thecurrentsanitationsituation(arepeopleusedto
“flying toilets”(plasticbags),pitlatrinesorflushtoilets?)andtheusers’expectationforthefuture.
ÿ Theprevailingnormsregardingreuseofhumanexcretaandrelatedtaboos.
ÿ Availableserviceproviderswhocanofferacollectionandmaintenanceservice.
Hence,carefulplanningwithstakeholderparticipationiscrucial.
2.4.2 User cooperation
Therearethreemainissuestobekeptinmindregardingusercooperation:1. Usershaveto“think a bit”whentheyuseUDtoilets
forthefirsttime(thispointdoesnotapplytowater-lessurinals,whichareusedinthesamewayaswater-flushedurinals).Thus,urinediversiontoiletsneedsomeupfrontawarenessraisingtoensurecorrectusageandsocialacceptance.
2. Ifusersdonotcooperate,toiletmisusecanresultinodour(e.g.ifusersurinateinthefaecescompartmentofaUDDT)orina“messed-up”toilet(e.g.ifusersdefecateintotheurinecompartmentofaUDtoilet)–althoughthisisnotdissimilarfrompitlatrinesandflushtoilets.
3. CleaningofUDtoiletsisalittlemoretimeconsu-mingthancleaningofconventionaltoilets,duetotheseparateurinesectioninthetoiletbowl.
2.4.3 Urine reuse/disposal issues
Thefollowingissuesregardingurinereuseordisposalareimportant:ÿ Urineneedstobetransportedtothereuseareaswhich
leadstoincreasedtraffic,andisproblematicifthedis-tancesarelarge(noise,airpollutionandCO₂emissions).
ÿ Whenurineisusedinagriculture,thefarmersneedtobetrainedonthecorrectmethods(see Section 3.1).
ÿ Ifurinecannotbereused,itissometimesinfiltratedintheground.Insomecircumstances,thishasnoad-verseenvironmentalimpacts.Inothercases,thiscanleadtogroundwaterpollutionwithnitrate(depen-dingontheamountofurineinfiltratedperarea,soilproperties,groundwatertable)–justlikewithpitlatrines(butwithpitlatrinesthereistheaddedpro-blemofpathogentransporttogroundwater).
2.4.4 Urine precipitation
TheinformationgiveninthissectionwasmainlytakenfromLarsenandLienert(2007).Infreshurine,themainnitrogencompoundisurea.Duringstorage,ureaishydro-lysedtoammonia/ammoniumandhydrocarbonatebyureaseenzymespresentintheurinestoragecontainer,soilandinaquaticsystems(see also Table 1).Thisprocessisaccompa-niedbyanincreaseinthepHvalue.TheincreasedpHvalueresultsinprecipitationofstruvite(MgNH₄PO₄)andcalciumphosphate(Ca₁₀(PO₄)₆(OH)₂)crystals.Thosecrystalscanformincrustations,alsocalled“urine stone”.
Precipitationinurinepipesandstoragetanksoccursinbothwater-flushedandwaterlesssystems.Inadditionskincells,hairandexcretedorganiccomplexeswillalsosettle.
Theendresultmaybehardprecipitates(incrustations)orsoft,viscous,paste-likeprecipitates(deposits).Incrustationstendtooccurontheinnerwallsofpipesandpipebends.Softdepositsoccurinstoragetanks(wheretheyformasludgeatthebottomofthetank)andinnear-horizontalurinepipes.
11 11 Thefollowingdesignparametersreducetheextentofprecipitation:ÿ Short retention time:precipitationoftenoccursat
locationswheretheurineflowvelocityisloworevenstagnant(suchassiphons,horizontalpipes,U-bendsofthetoilet).Sucharrangementsshouldthereforebeavoided.
ÿ Smooth surfaces and hydrophobic materialsshouldbeused.Scratchingofsurfacesbymechanicalcleaningshouldbeavoided.PlasticPVCpipesarecommonlyusedforurinepipes.
ÿ Ifflushingwithwater:Flushing with soft water,suchasrainwater,ispreferredtoflushingwithhardwater(softwaterhaslesscalciumandmagnesiumwhichcanprecipitatewiththeurine’sammoniumandphosphate).
ÿ Pipes with a relatively large diameter (atleast2.5cm)arelesslikelytogetclogged.
Usingnoflushwateratall(asinwaterlessurinals)doesnoteliminatetheproblem,sinceurinealsocontainscalciumandmagnesiumwhichcanprecipitatewithammoniumandphos-phatetoformstruvite.InwaterlessUDsystems,moresoftdepositstendtooccurthanhardincrustations,whereasforwater-flushedUDsystemsitistheotherwayaround.Informa-tionaboutmaintenancetaskstopreventorremoveblockagesinurinepipesisprovidedinSection 6.4.
2.5 Quantity of urine
Thequantityofurineproducedbyanadultisaround0.8to1.5Lperadultperday(WHO,2006,Volume4)–itmainlydependsontheamountapersondrinksandhisorhertranspi-ration.Childrenproduceapprox.halfasmuchurineasadults.Awidelyuseddesignfigure,basedonSwedishdata,is1.5 L/cap/d (or 550 L/cap/year)2.
2.6 Quality of urine2.6.1 Source considerations
Thedescriptionofurinequalityinthissectionappliestourinecollectedwithoutcross-contaminationwithfaeces.Suchcross-contaminationisdealtwithviaurinetreatmentmethods(see Section 2.7).
Additionally,itshouldbehighlightedthatthequalityofthecollectedurineisrelatedtothehealthandlifestyleofthepeopleexcretingitandtotheurinecollectionsystem.Forex-ample,ifurineiscollectedfromahospitaloranold-agehomeitwillmostlikelycontainmorepharmaceuticalresiduesthanurinefromhealthyandyoungpeople.Andifurineisledthroughcopperpipesitmayhaveahighcopperconcentration.Thishastobekeptinmindduringthedesignphase,especiallywhenreuseisplanned.
2.6.2 Pathogens
Therearefourtypesofpathogensrelevantforsanitation:bacteria,viruses,parasiticprotozoaandintestinalhelminths.Itisimportanttoknowthaturineinthebladderofahealthypersonissterile(meaningitcontainsnopathogens).Onlyveryfewdiseasesaretransmittedviapathogensinurine.Theonlydiseasewhichneedstobeconsideredfromariskperspec-tivewhenurineisreusedinagricultureisSchistosoma haema-tobium–andonlyinareaswherethisdiseaseisendemic(WHO,2006,Volume4).Incontrast,theamountofpatho-gensinfaecescanbeveryhigh,dependingontheprevalenceofdiseasesinthepopulation.
2.6.3 Nutrients
Macro-nutrientsinexcretaincludeN,P,KandS(nitrogen,phosphorus,potassiumandsulphur)ofwhichNandParethemostimportant.
Withregardstothenutrientscontainedinurine,thefollow-ingdesignfiguresareused(derivedmainlyfromSwedishdatabutconsideredtobequiteuniversal,seeJönssonetal.,2004):ÿ Massofnutrientsexcretedwithurine:4kgN/cap/yr,
0.36kgP/cap/yrand1.0kgK/cap/yr.ÿ Concentrationsofmacro-nutrientsinurine(design
figure):7300mg/LN;670mg/LP;1800mg/LK.ÿ Concentrationfiguresarebasedonaperson’sdiet
andshouldpreferablybeverifiedonsite.ÿ 80%ofthenitrogenexcretedbyapersonisexcreted
withtheurine,andtherestwiththefaeces.Hence,intermsofnitrogenfertiliser,urineismoreimportantthanfaeces.Forphosphorus,55%isexcretedwiththeurine,therestwiththefaeces.
ÿ Adultsexcretethesamemassofnutrientsastakenupintheirdiet,asthereisnoretentionofnitrogenandphosphorusinthehumanbody,exceptforchildrenwhereasmallamountisretainedforbonegrowth.
Thechemicalcompositionoffreshandstored3urineissummarisedinTable 1(see next page) andthefollowingobservationsarehighlighted:ÿ Freshurinecontainsnitrogenmainlyintheform
ofurea;storedurinecontainsnitrogenmainlyintheformofammonium/ammonia(thetransformationprocessisdescribedinSection 2.7.2).
ÿ Thelowerphosphate,magnesiumandcalciumcon-centrationsinstoredurinecomparedtofreshurineareduetoprecipitationprocessesduringstorage.
2 Cap=capita=person
3 Storedurinemeansurinewhichiscompletelyhydrolysed(Udertetal.,2003),andthistypicallyoccurswithin2-4weeksdepen-dingontheamountofureasepresent(Maurer,2007).
1212
2.6.4 Micro-pollutants
Micro-pollutantsinurinecouldincludethefollowingcategoriesofsubstances:1. Naturalhormones2. Pharmaceuticalresidues,includinghormones
fromcontraceptivepill3. Heavymetals4. Persistentorganicpollutants(POPs)
Thelasttwocategoriesofmicro-pollutants–heavymetalsandPOPs–arevirtuallynon-existentinurineastheywouldoriginatefromthefoodapersonhaseaten.Urineisanim-portantpathwayforthebodytoeliminateorganicdegrada-tionproductswhicharetoxictothehumanbody,butthesesubstancesareeasilybiodegradablebysoilmicroorganismsafterexcretion.Thefirsttwocategoriesofmicro-pollutants–thenaturalhormonesandpharmaceuticalresidues–dooccurinurineandcanbemanaged(see Section 2.7.3 and 3.2).
2.7 Urine treatment2.7.1 Treatment objectives
Urinetreatmenthasthefollowingobjectives:ÿ Pathogen kill(thisisthemainobjective):Collected
urinemaybecontaminatedwithfaecalpathogensif
carelessusersdepositfaecesintheurinecompartmentofaUDtoilet(thisistermed“cross-contamination”ofurinewithfaecalmaterial).Asmentionedabove,pureurineisvirtuallypathogen-free.
ÿ Otherpossibletreatmentobjectivesmayinclude: „ Volumereductionbyevaporationorbyconversion
intosolidform(struvite)toreducetransportcosts. „ Extraction(furtherconcentration)ofnutrients. „ Eliminationofmicro-pollutants.
2.7.2 Treatment by storage
Thesimplest,cheapestandmostcommonmethodtotreaturinewiththeaimofpathogenkill,isextendedstorageinstoragetanks.
Storageofurineinaclosedtankorcontainer(notnecessarilygastight)isanefficienttreatmentmethodforreducingpatho-gensinurine:Thedecompositionofureaintoammonia/ammoniumandhydrocarbonate–whichisfacilitatedbythenaturalenzymeurease–leadstoanincreased pH value(pHaround9)whichhasasanitisingeffect(meaningitkillspatho-gens),sothatbacteria,parasiticprotozoa,virusesandintestinalhelminthsdieoffovertime.Anenvironmentwithahightem-peratureandlowdilutionwithwaterenhancesthiseffect.Timeitselfalsoleadstopathogenkill.
Safereuseofurineinagriculturecanbeensuredifthefol-lowingrecommendedstoragetimesareused(fordetailsseeWHO,2006,Volume4):ÿ Urineoriginatingfromlargersystems(communitylevel)
–wherecross-contaminationwithfaecescannotberuledout–shouldbestoredforatleastonemonthifitisusedonfoodorfoddercropswhichareprocessed.Forahighersafetymargin,6monthsofstoragecanbeused(inwhichcasetheurinecanbeusedonallcrops).Butiftheammonialevelintheurineisgreaterthan2 mgN/L(whichitshouldbeforundilutedurine)thenshorterstoragetimeswillsuffice(Winkeretal.,2008).
ÿ Nostorageisneededwhenurinefromownproduction(orfromsystemswherecross-contaminationwithfae-cesisdefinitelynotoccurring5)isusedforcropsgrownforownconsumption.Thisisbecausediseasetrans-missionwithinthehouseholdviatheurine-oralrouteismuchlesslikelycomparedtoday-to-daycontactofthehouseholdmembers.
2.7.3 Other urine treatment technologies
Advancedurinetreatmenttechnologiescanincludebio-logicalprocesses(nitrification),chemicalprocesses(struviteprecipitation;ozonation)orphysicalprocesses(membrane-based).Someofthesehigh-techmethods(suchasozonation
Parameter Freshurine Storedurine
pH 6.2 9.1
Total nitrogen, TN (mg/L) 8830 9200
Ammonium/ammonia-N, 460 8100NH4
+ and NH3 (mgN/L)
Nitrate/nitrite NO3 + NO2 0.06 0(mgN/L)
Chemical oxygen demand, 6,000 10,000COD (mg/L)*
Total phosphorus, TP (mg/L) 800 – 2000 540
Potassium, K (mg/L) 2740 2200
Sulphate, SO4 (mgSO4/L) 1500 1500
Sodium, Na (mg/L) 3450 2600
Magnesium, Mg (mg/L) 120 0
Chloride, Cl (mg/L) 4970 3800
Calcium, Ca (mg/L) 230 0
* COD is a measure of the organic components.
Table1. Average chemical composition of fresh urine (literature values) and stored urine (simulated values, see Udert et al. (2006))4. Significant changes during storage are indicated in bold.
5 Forexamplewhenurineiscollectedfromwaterlessurinals.4 Source:Maurer(2007)
13 13 andmembrane-basedprocesses)canremovemicro-pollutantsfromurine(seeLarsenandLienert(2007);Tettenborn(2007)).Thisisusefultoknowifthereisconcernaboutmicro-pollutantsinurine(see Section 3.2).
2.8 Are UD systems more cost effective?
Possiblecostsavingsofurinediversionsystemsmaybere-latedtothefollowingaspects(ineachcase,oneneedstocon-siderwhichsystemsarebeingcompared):ÿ Ifacentralisedsewersystemandwastewatertreatment
plantcanbeavoidedbyusingUDtoilets,thencostsavingswillbesignificant.However,thecollectionandtreatmentofgreywater, industrial wastewater and rainwaterstillrequiresasewersystemofsomesort(separate,decentralisedsystemsmayoftenbepreferable).NotethattheremaininggreywaterinUDsystemscontainsafarlowerconcentrationofpatho-gensandnutrientscomparedtoconventionaldomesticwastewater.
ÿ Inregionswherewaterisscarceandexpensive,watersavingsfromUDtoilets(inparticularUDDTs)canleadtooverallcostsavingscomparedtoflushtoilets.
ÿ Inregionswheresoilfertilityispoorandfertiliserex-pensive,farmersmayhaveproductioncostsavingsorhigheryieldswhenusingurineasafertiliserinsteadofmineralfertiliserornofertiliseratall.
Regardingpotentialenergysavings,thisneedstobeanalysedonacasebycasebasis.EnergysavingsmaybepossiblewithUDsystemsinthreeareas:1. Ifthesystemissetuptouselesswater,energysavings
arepossiblewithrespecttopumping,processinganddistributionofthetapwater.
2. Energysavingsmaybepossibleatthewastewatertreatmentplant,whichreceivesalowerloadofnitro-geninthesewageifurineiscollectedseparately(hencelessoxygenrequiredfornitrificationprocess).
3. Ifurinereplacesartificialmineralfertiliser,thenener-gysavingsarepossibleforfertiliserproductionaswellasforfertilisertransport(mostAfricancountrieshavenolocalmineralfertiliserproductionfacilities).
Alifecycleanalysis,comparingtheenergydemandfornutri-entremovalandmineralfertiliserproductionversusnutrientrecoveryidentifiedaconsiderableenergysavingpotentialwithurinediversionnutrientrecovery(Maureretal.,2003).
Ontheotherhand,thefollowingaspectscanleadtoUDsystemshavinghighercoststhanconventionalsystems:ÿ Incomparisonwithconventionalsewer-basedsanitation
systems,urinediversionsystemsusingUDflushtoiletstendtohaveahigherinitialinvestmentcostastheyre-quireadditionalcomponentsfortheseparatecollection,transportandtreatmentoftheurineandfaeces.
ÿ AUDDTusuallyhasaslightlyhighercapitalcostthanasimplepitlatrineor–ofcourse–thedo-noth-ingoptionofopendefecation.
Adequatefinancingandoperatingschemeshavetobefoundthatensurefinancialsustainabilityandmakethesystemafford-ablefortheusers.FurtherinformationisavailableinthefactsheetoftheSuSanAworkinggroupon“costs and economics”(http://susana.org/lang-en/library/rm-susana-publications?view=ccbktypeitem&type=2&id=609).
2.9 Technical components used for achieving UD
Toachieveurinediversion,thefollowingtechnicalcom-ponentsareused:waterlessurinals,urinediversiontoilets,urinepipingtoaurinestoragetank(ortoasewer)andareusesystemfortheurine.FurtherinformationisprovidedinSections 4 to 6.
TherearetwomainvariantsofUDtoilets:UDDTs(urine-diversiondehydrationtoilets-noflushwaterisusedatall)andUDflushtoilets(waterisusedtoflushthefaecesawayandtorinsetheurinecompartment).
3 Reuse of urine as fertiliser in agriculture
3.1 How to use urine as a fertiliser
Whensanitationprojectsaresetupwherecollectedurineistobeusedasfertiliser,consultationwithfarmersandsoilfer-tilityexpertsisessential,astheengineerssettingupthesanita-tionprojectsusuallylackthenecessaryagriculturalexpertise.
3.1.1 Basic guidelines
Thebenefitsofurineasafertiliseranditsapplicationme-thodshavebeenwelldocumented,forexampleinGenschetal.(2011),Richertetal.(2010),SuSanA(2008),Morgan(2007),WHO(2006)andJonssonetal.(2004).Somehigh-lightsfromthesedocumentsaresummarisedbelow.
Urineisaquickactingfertiliserthatcanbeusedforanycropswhichrequirethemacro-nutrientsN,P,KorS(nitrogen,phosphorus,potassiumorsulphur6).Thefertilisingeffectsofthesenutrientsinurinearethesameasthoseofartificialmineralfertiliserifthesameamountofnutriensisapplied.Hence,reuseofurineinagriculturehasthepotentialtore-ducedemandforartificialmineralfertiliser.
6 Sulphurisanimportantmacro-nutrient,neededinapproximatelythesameamountasphosphorus,andoftenlacking.
1414 Belowaresomerulesofthumbfortheuseofurineasaferti-liserwithrespecttoitsnutrientcontent(takenfromJönssonetal.(2004)andothers):ÿ Urineisanitrogen-richcompletefertiliser,containing
alsosodiumandchloride.Thismakesitwellsuitedasfertiliserforcropsthrivingonnitrogen(suchasmaize)andespeciallyforcropsalsoenjoyingsodium,suchaschard(similartospinach).Careshouldbetakenwhenapplyingitforcropssensitivetochloride(suchaspota-toesandtomatoes),althoughyieldsofthesecropscanalsobemuchimprovedbyappropriateurineapplication.
ÿ Ifallurinefromonepersoniscollected,itwillsufficetofertiliseabout300-400 m²ofcropperpersonperyear,e.g.producingforexample250kgofmaize(roughlyequaltothefoodintakeofonepersonperyear).
ÿ Applytheamountofurinethatonepersonexcretesinonedayonone square metrepercroppingseason(thismeansapprox.1.5Lundilutedurinepersquaremetre).Ifweassumethatthereis7gN/Linurine(typicalvalueforSwedishconditions),then1.5Lurine/m2willcor-respondto105kgN/ha,whichisalowtonormaldoseforcereals(dependingonthecountry,soilandexpec-tedharvestfromthefield).
ÿ Thecropyieldalsodependsverymuchonthesoil,andurinewillalwaysworkbetterin“living soils”comparedtobarren,sandysoils.Thenitrogenconvertingbacte-riamustbepresentandcomposthelpsenormously7.
Somerecommendationsforthemethodsonhowurineshouldbeappliedasafertiliserare:ÿ Betweenlastfertilisationandharvestaperiodofat
leastonemonthshouldalwaysbeapplied(forbothlargeandsmallscalesystems).
ÿ Thepersonapplyingtheurinetothefieldsshouldfollowgoodpersonalhygienepractices(thoroughhandwashingafterapplyingtheurine,andifpossiblealsowearingglovesandboots).
ÿ Thebestnitrogenfertilisingeffectisobtainedwhenurineisappliedclosetothegroundanddirectlyincor-poratedorwateredintothesoilinordertominimiseammonialossestotheair.Inordertoavoidleaching,andforclimateswithheavyrainfallorverysandysoils,frequentapplicationofsmallamountsofurineisfavourablebutnotessential.Itisnecessarytobalancemaximumcropyieldwithwhatispracticalinreallife.
ÿ Urineshouldalwaysbeappliedtothesoilnext to the plant(infurrows)butnot ontotheplant.Otherwiseitmightleadto“burning”oftheleaves.Note:“We fertilise the soil, not the plant!”.
3.1.2 Specific advantages of urine compared to other mineral fertilisersAspointedoutbyElisabethKvarnström(StockholmEnvironmentInstitute),oneofthegreatadvantagesofurineisthat“the content of heavy metals and organic compounds is very low, as these only come from the food which you have once consi dered having a high enough quality to ingest. Artificial mineral fertilisers can have a relatively high content of heavy metals.”
Secondly,whenfarmersareabletousetheurinefromtheirfamiliesandneighboursintheirownfields,thisfertiliserisessentiallyforfree(butifurinehastobetransportedoveradistancefromproductiontouse,therearetransportcosts).
Urinefertiliserisalsoindependentfromtheavailabilityandpriceofmineralfertiliserontheworldmarket.Furthermore,urinecontainsmicro-nutrientswhichthesoilmayneedforhighersoilfertility.
3.1.3 Disadvantages of urine compared to other mineral fertilisers
Whilsturineisaprovenfertiliser,ithassomedrawbackscomparedtoartificiallymanufacturedchemicalfertilisers:ÿ Urineis,comparedtoartificialfertilisers,adiluted
fertiliser:TheN,P,KandSconcentrationinurineismuchlowerthaninartificiallymanufacturedferti-liser.Urine’snutrientcontent–expressedwiththein-ternationalfertiliserconventionofN:P₂O₅:K₂O8–isapproximately0.7:0.15:0.22–comparedtoforex-ampledi-ammonium-phosphate(DAP)or(NH₄)₂HPO₄withthecompositionN:P₂O₅:K₂Oof21:46:0.Thismeansthatahugevolumeofwateristransportedwheneverurinefertiliseristransported.
ÿ Urinecontainstracesofpharmaceuticalresiduesandhormones,andpotentialbuyersofcropsfertilisedwithurinemaybeputoffeveniftheactualhealthrisksareextremelylow(see Section 3.2).
ÿ Urineisamulti-componentfertiliser,containingN,P,KandSinaslightlyvariableratio,whichmayormaynotbetherightfertiliserforagivensoilandcrop.Themacro-nutrientconcentrationsinurinemayvarysomewhat(althoughinrelativelynarrowranges),de-pendingonpeople’sdietandwhethertoiletusersaddflushwatertothetoilet.
ÿ Urineisaliquidfertiliser,whilstsomefarmersmaypreferasolidfertiliserifthisiswhattheyareusedto(unlessurineisconvertedtostruvite,byadditionofmagnesiumandraisingpH,whichisalsoaprovenprocess).
8 Thismeans0.15%byweightofP₂O₅,or1500 mg/LP₂O₅(mul-tiply%valueby10,000).
7 Source:PeterMorgan,Aquamor,Zimbabwein2008
15 15 Thefollowingdisadvantagesarenotspecifictourineasafertiliserbutstillneedtobekeptinmind:ÿ Likeotherfertilisers,urinecancauseplantfertiliser
burn(alsocalledleafscorch)ifnotappliedcorrectly.Fertiliserburnisthevisiblesymptomofinsufficientwaterinaplantassociatedwithanoverapplicationoffertilisersalts(saltsdissolvedinurine)9.
ÿ Urineaddssalinitytothesoilandthereforeitsuseasfertilisertopotplantsisonlyrecommendedwhenthesoilcaneasilybeexchanged.
ÿ Alsolikeotherfertilisers,urinecanleadtoground-waterpollution(withnitrate)andnutrientrun-off(resultingineutrophicationinwaterbodies)ifexcessamountsareapplied.
ÿ Urineisamulti-componentfertiliser(withafixedratioofN,P,KandS)whichshouldonlybeapplieduntilthefirstnutrientreachesitsoptimumforthesoil(probablynitrogenorsulphur).Otherwise(ifapplieduntilphosphorusissufficientlysupplied)itcancauseover-fertilisationofnitrogenandsulphur.
3.1.4 Should urine be applied undiluted or diluted with water?
Urinecanbeappliedeitherundilutedordilutedwithwater,dependingonthesoilandthegardener’sorfarmer’spreferences.Somegardenersdiluteurinewithwaterinaratioof1:3,1:5orevenupto1:15,andthisdilutionhasthefollowingadvantages:1. Reducesriskofplant“ fertiliser burn”(see previous
section).2. Enablesirrigationandfertilisationinonestep(also
called“ fertigation”)andwithonepieceofequipment.Butnozzlesofdripirrigationmayclogwhenaurine-watermixtureisusedforfertigation.
3. Reducesodourduringapplication,especiallyifahighdilutionratioisused(1:5orgreater).
4. Minimisestheriskofapplyingtoomuchfertilisertopottedplants,asthepotwilloverflowbeforetoomuchnitrogenisapplied.
Ontheotherhand,applyingurineundilutedhastheadvan-tagethatasmallervolumeofanodorousliquidhastobehandled.
Whenapplyingurineundiluted,fertiliserburnoftherootsisavoidedbyaddingurineinfurrows,somewhattothesideoftheplants(approx.15cm).Odournuisanceisminimisedbyimmediatelycoveringtheurinewithsoilaftertheurinehasbeenaddedtothefurrows.Usually,irrigationwaterisaddeddirectlyaftertheurineapplication.
3.2 Are hormones and pharmaceutical residues in urine problematic for reuse?
TheinformationinthissectionisbasedonWinker(2009)andtheinputfromArnoRosemarin(StockholmEnvironmentInstitute).ThepublicationofLarsenandLienert(2007)isalsorecommendedinthiscontext.
Hormonesandpharmaceuticalresiduesaretwotypesofmi-cro-pollutantswhichoccurinurine(concentrationlevelsareavailableinWinker(2009)),ashumansexcretethemwiththeirurineandfaeces(asaruleofthumb:twothirdsofphar-maceuticalresiduesubstancesareexcretedwiththeurine,onethirdwithfaeces,althoughthefigurescanvarywidelyforin-dividualsubstances10).
Ifurineisreusedinagriculture,someofthesemicro-pollu-tantscanbetakenupbyplantsandtherebyenterthehumanfoodchain.Thisisarisk,butasmallone.Afullevaluationofthepotentialtoxiceffectsofpharmaceuticalsingestedbyhu-mansviaurine-fertilisedcropsisverydifficultandhasnotyetbeendone.Thepotentialrisksfromconsumingcropsfertilisedwithurineneedtobecomparedwiththerisksrelatedtopesti-cideuseoncrops,aswellasantiobioticsandhormonesgiventofarmanimals(poultryandcattle)whichcanbetracedforexampleinmilkandeggs.Attheendoftheday,itcomesdowntoariskanalysisandriskmanagementstrategy.
Animalmanuresandsewagesludgecontainingpharmaceuti-calresiduesandhormonesarealreadynowbeingusedonfields.Itwasshownthattheloadofhormonesandantibioticsinhumanurineisinfactmuchlowerthaninanimalmanure(howevernotallgroupsofsubstancescanbecomparedinthiswayastheyarenotallpresentinanimalmanure).Withsewer-basedsanitationsystems,thesetypesofmicro-pollu-tantsarenotremovedinconventionalsewagetreatmentplantsandarethusdischargedintosurfacewaterbodiesandcanreachthegroundwater(detectedconcentrationsofpharma-ceutialresiduesingroundwaterareintheorderof50 ng/LinseverallocationsinGermany).
Whencomparingthetwoapproaches(dischargingurinewithtreatedwastewatertosurfacewaterversusurineapplicationtosoil),itislikelytobesafertodischargeurinetosoilratherthanwater.Themicro-pollutantscanbedegradedbetterintheaerobic,biologicallyactivesoillayers(highconcentrationofmicro-organismspercubiccentimetre)withlongerresidencetimesthaninwaterbodieswhoseecosystemsaremuchmoresensitive.Thishaspreviouslybeenproveninthecaseofhor-mones11,andmoreresearchisneededtoproveitforothertypesofmicro-pollutantsaswell.
10 Tobemoreprecise:around70%ofpharmaceuticalsubstancesareexcretedviaurineaccountingfor50%oftheoverallecotoxicologicalrisk(LarsenandLienert,2007).Theecotoxicologicalriskofthefractionofpharmaceuticalresiduescontainedinurineandinfaecesisthesameregardlessofthehighernumberofsubstancesexcretedviaurine.11 Thisfindingisofparticularrelevanceregardingtheartificialhormoneswhichareexcretedinurinefromwomentakingthecontraceptivepill.
9 Rootcellsactivelyabsorbfertilisersaltsfromsoilsolution,andundernormalconditionsmaintainahigherosmoticpressure.Ifexcessfertilisersaltsareapplied(i.e.concentratedurinewhichisnotdiluted),theosmoticpressureofthesoilsolutionisraised.Thismeanswatercan-notenterthecellandmayactivelymoveoutofit.Theresultinginjuryisknownasfertiliserburnorphysiologicaldrought(RobertHolmer,Ecosanresdiscussionforum,2008).
1616 Terrestialsystems(soil)aremoresuitablefornaturaldegra-dationofpharmaceuticalsthanaquaticsystemsbecause:ÿ Theoxygenlevelsarearound50,000timeshigher
insoilthaninwater.ÿ ExposuretoUVlighthelpstodegradepharmaceuti-
cals,althoughthisonlyappliestothesurface(1-2cmsoildepth)andcropscanshadetheground.
ÿ Thehighspecificsurfaceofsoilparticlesmaximisestheexposureofadsorbedchemicals,maximisingthekineticsofdegradation.
ÿ Thewidebiodiversityofthefungalandbacterial floraofsoilisadaptedtodegradevarioustypesoforganicmolecules,bothcomplexandsimple.
Finally:“Drug residues in sustainable sanitation products used to supply plant nutrients can hardly be a serious issue in regions where malnutrition, groundwater and surface water pollution due to inappropriate sanitation and irrigation with untreated wastewater is a reality”12.
3.3 Is urine an “organic fertiliser” and can it be used in organic farming?
Thedefinitionof“organic fertiliser”maybeaccordingtotwodifferentcategories:1. Organicintheanalytical chemistry sense(acom-
poundwhichcontainscarbonandmaycontainotherelementssuchashydrogen,oxygen,nitrogen).
2. Organicina“green”, “eco” or “natural”sense.
Freshurinecontainsureaandisthusanorganicfertiliserintheanalyticalchemistrysense.Storedurinecontainsammo-niaandnourea(see Section 2.6.3),andisthereforenotorganicbutrathera“mineral fertiliser”intheanalyticalchemistrysense.Inotherwords:Urineisbothanaturalmineralisedormineralfertiliser,andanorganic,ecologicalornaturalferti-liser13.
The“organic farming”14regulationsdifferbetweencountrieswithregardstowhichtypeoffertiliserisallowed(andisinthiscontextcalled“organic fertiliser”).Forexample,countriesintheEuropeanUnionaresubjecttotheEUorganicfarminglegislation,whereurineisnot consideredanallowedfertiliser.InChinaontheotherhand,urineisconsideredanaturalfer-tiliserandthusallowedinorganicfarming.Makingurineal-lowedfororganicfarmingintheEUremainsanimportantchallenge.Itshouldbepossibleasurineisanaturalfertiliserwithasimilarcompositionasforexamplepigurine.
4 Waterless urinals
Thischapterdrawsonthepublicationbyv.MünchandDahm(2009).Note:“waterless”means“without water”inEnglish.Somepeoplealsousetheterm“waterfree”.Wedonotrecommendanyparticularurinalmodelinthispublication.
4.1 Definition and purpose
Aurinalisaspecialisedtoiletforurinatingonly,whichisusedwhilestandingup,andisdesignedprimarilyformaleusers.Urinalsarewidelyusedaroundtheworld,especiallyinpublicfacilitiesbeingfrequentedbyalargenumberofboysandmen,becausetheysavespaceandcostscomparedtotoi-lets(simplerdesign;noseparatecubiclesneeded,althoughinmanycasesseparationpanelsareinstalled).Urinalsarenotcommonlyusedinprivatehouseholdsduetotheiradditionalspacerequirements.
Alimitednumberofurinalsforfemales(tobeusedwhilestandingorsquatting)areonthemarketbuttheyarenotwidelyacceptedforvariousreasons,suchasfemaleshavinggreaterneedsforprivacyastheyhavetopartiallyundress.Squatting-typeurinals(squattingpanswithoutanoutletforfaeces)aresometimesusedforgirlsinAfricanorAsianprima-ryschoolstosaveonspaceandcostscomparedtotoilets.
Conventionalurinalsareflushedwithapprox.4Lofwatereitheraftereachuseorbasedonatimer,whereaswaterlessurinals(see Figure 1)usenowaterforflushing.
Themainmotivationforusingwaterlessurinalsisto:1. Savewaterandhencecosts–theseurinalsare
connectedtoasewersystem.2. Allowcollectionofpure,undilutedurineforusein
agricultureasanitrogenandphosphorus-richfertiliser–theseurinalsareconnectedtoaurinestoragetank.
Waterlessurinalsarethefirstandeasieststeptowardsurinediversionand,possibly,ecologicalsanitation(ecosan).
12 Source:JörnGermeronEcosanresdiscussionforum,April2009.13 Source:HåkanJönsson(onEcosanresDiscussionForum,De-cember2008,http://www.ecosanres.org/discussion_group.htm)14 Apossibledefinitionof“organic farming/agriculture”:Organicagricultureisaproductionsystemthatsustainsthehealthofsoils,eco-systemsandpeople.Itreliesonecologicalprocesses,biodiversityandcyclesadaptedtolocalconditions,ratherthantheuseofinputswithadverseeffects.Organicagriculturecombinestradition,innovationandsciencetobenefitthesharedenvironmentandpromotefairrelationships
andagoodqualityoflifeforallinvolved(source:InternationalFederationofOrganicFarmingMovement,http://www.ifoam.org/).
Figure 1. Waterless urinals for men. Left: Centaurus model of Keramag company. Right: Plastic urinal from Addicom, South Africa, with EcoSmell-stop device (sources: (left) E. v. Münch, Delft, 2006; right: Addicom).
17 17
4.2 Historical development of waterless urinals
In1894,Mr.BeetzfromAustriapatentedadrainagedevice(trap)whichallowedurinalstobemade"flushless".Thetrapusedasealantliquid(themechanismisexplainedin section 4.4.3).ThispatentwasthencommerciallyexploitedbythecompanyF.ErnstEngineerinZürich,Switzerlandwhowasthesolesupplierofwaterlessurinalsworldwideforapproximately100years.
Intheearly1990s,watersavingcameintofashionandseveralcompaniesappearedonthemarketusingderivativesoftheBeetzpatent.AtmoreorlessthesametimeHepworth,aUKplumbingmanufacturer,patentedadrainagedevice(onewayvalve)whichwasinfactaflattube.Asimilardeviceisusedinsmallboatstodrainspraywaterfromthebilge.Derivativepatentsoftheflattubeelementsareusedtodayinwaterlessurinalsandmarketedbyvarioussanitarywarecompanies,forexampleKeramag(modelCentaurus).
In2002,aSwissengineerlivinginSouthAfrica(PeterDahm)patentedaonewayvalvesimilartotheflattubedesignbutusinga“curtain”mechanisminordertoreducemaintenancerequirements.Thisunit,whichisnowusedinwaterlessuri-nalsofseveralsuppliers,issoldunderthenameofEcoSmell-stop(ESS).
Atpresent,Germanyisprobablythecountrywiththehighestnumberofwaterlessurinalspercapita,asthepriceofmunici-paltapwaterinGermanyisoneofthehighestintheworld,andGermansareconsequentlyveryinterestedinallwater-savingopportunities(1,200waterlessurinalsofKeramagareinuseinthepublictoiletsofHamburginGermany).
Waterlessurinalsarecommonlyusedinindustrialisedcoun-triesforpublictoiletswhicharenotconnectedtothesewer(suchasreststopsalonghighways).Itwouldbebeneficialiftheybecamewidelyusedindevelopingcountriesaswell.
4.3 Odour control methods (general)
Togainwideacceptance,waterlessurinalsmustmeettheacceptedstandardsapplicableforconventionalwaterbornein-stallations.Theirodouremissionmustbelessoratworstequaltotheoldsystem.Toachievethisodour-freeperformancefouraspectsareabsolutelycrucialforwaterlessurinals:1. Suitablemechanismtoblocktheodourcomingback
fromthesewerandurinestoragetank,forexample(discussedindetailinthesections below):
„ rubbertubeseal „ curtainvalveseal „ sealantliquid(blockingfluid) „ plastictabletennisballplacedinafunnelwhich
isinsertedintheopeningofajerrycan;or
„ placeurinalinawellventilatedarea(locatedoutside
ofhouses),andputupwithsomeodour(maybepossibleforruralareas).
2. Appropriatesurfaceoftheurinalbowl(smooth,non-sticky,e.g.withwaxcoating).
3. Correctlydesignedinterrelationbetweenurinalbowlandthedrainfittingtominimisecreviceswhereurinecanaccumulate.
4. Onanoperationallevel:athoroughmaintenancere-gardingthebowlandtheodourblockingdevice.Thesurfaceoftheurinalbowlisusuallywipedcleanonce,twiceorseveraltimesperdaywithamoistsponge.Fortheodourblockingdevice,themaintenancedependsonthespecificationsoftheurinalsupplier(see below).
4.4 Odour control for connection of urinal to sewer or storage tank4.4.1 Rubber tube seal
Forthismethod,aflatrubbertubeisused(Figure 2).Thisrubbertubeisflatatthebottomwhennotinuse(andhenceblocksodourfromthesewerorurinestoragetank)butopensupwhenurineisflowingthrough.Thisone-wayvalveallowspassageofgritupto2mm.
Urineprecipitates(“urine stone”),whichsticktotherubbertubeneedtobecleanedoffwithwaterregularly(otherwisetheflatrubbertubedoesnotcloseproperlyanymore).Thecleaningfrequencydependsonthenumberofusesperday(cleaningoncepermonthunderaveragecircumstancesmaybesufficient).Therubbertubeneedstobereplacedaroundonceayear.Therubbermaterialissensitivetosolvents,acids,anddeodorisingtabletsoftenusedinurinals.Therefore,theuseofacidsoraggressivecleaningagentsmustbeavoided.ThissystemisusedforexamplebytheGermancompanyKeramagintheirCentaurusmodel.
4.4.2 Curtain valve seal
Thecurtainvalvesealissimilartotherubbertubeseal,butwasdesignedtoreducemaintenancerequirements.Thistypeofone-wayvalvehas“self-cleaning properties”asasmallpressuredifferenceforcestheurinetowetthewholeinnersurfacebetweenthe“curtains”,thereforeflushingthemclean.Theelementisdesignedinamannertominimisebuild-upofurineprecipitatesorurinesludgeandthuskeepingthesealingsurfacesclean.Liketheflatrubbertubeseal,thisone-wayvalvealsoallowspassageofgritupto2mm.Thesiliconcurtainelementisintegratedintoaplasticcasing(Figure 2).TheplacingoftheEcoSmellstop(ESS)elementintoaplasticsleevehastwopurposes,firstlytoguaranteethat
1818 noodourfromthesewerorurinestoragetanksescapesintotheroom,andsecondlytoallowaneasyremovaloftheESSunitformaintenancepurposes.Forreplacementofthecurtain(ifsimplecleaningisnolongerpossible),theentireplasticcasingisremovedwithasmallplasticextractortool(Figure 3),thendiscardedandreplacedwithanewESS.Thisreplacementprocessmaybenecessaryaboutonceperyearandtakesonlyafewseconds.ItcanbeperformedwithouthavingtotouchtheESSelementbyhand.
TheESSmanufacturingprocessisnotsimpleastheinjectionmouldsareofextremecomplexity,andthemixingandinjec-tionrequiresverysophisticatedmachinery.Forthisreason,itisnotyetpossibletomanufacturetheESSlocallyindevelo-pingcountries,butitcaneasilybeimportedasitissmall,light-weightandlow-cost.ThispatentedESSunitisusedbythecompaniesAddicom,KellerinventAGandF.ErnstInge-nieurAG15since2006.
4.4.3 Sealant liquid (blocking fluid)
Thissystemworkswithasealantliquid(alsocalledblock-ingfluid)whichismadeofvegetableoilsoraliphaticalcohols–theyarebiodegradableifreleasedtothesewerorurinestor-agetank.Thesealantliquid,withaspecificgravityofaround0.8,floatsontopoftheurinecontainedinthetrapandthusconstitutesaneffectiveodourbarrier.Urineimmediatelype-netratesthesealantliquidandflowstothedrain.Urinepre-cipitatesarecollectedinacartridgeorinnercylinderofthetrap.Themaintenanceprogramofwaterlessurinalswithasealantliquidconsistsofcleaningoftheurinalbowl,andtheregularexchangeofthecartridge(orthesealantliquid,see Figure 4 ).Therequiredexchangefrequencydependsonthenumberofusers.Witheachuseandinbetweenuses,someurineprecipitatesaccumulatewhicheventuallyrendersthetrapinoperative.Foreignobjects,suchascigarettestubs,acceleratetheprocess.Atthispointthecartridgehastobecleanedorreplaced.
Ifthetrapstartstosmell,whileitisstillfreelypassingurine,merelyarefillwiththesealantliquidcanresolvetheproblemforsomedesigns.IntheUSA,thisiscurrentlythemostcom-montypeofwaterlessurinal,asundercurrentlegislationonlytheseliquid-filledtrapsareapprovedforwaterlessurinals.
Figure 2. Two types of odour seals for waterless urinals. Left: Flat rubber tube (Keramag Centaurus). Right: (left side) See-through pipe fitting; (right side) see-through EcoSmellstop (ESS) unit showing the blue silicon curtain one-way valve inside (source: (left) E. v. Münch, 2007; (right) Addicom).
Figure 3. EcoSmellstop (ESS) unit with pipe fitting and extractor. Inside the ESS is the silicon curtain valve (source: Addicom).
Figure 4. Example instruction sheet, showing replacement of sealant liquid for Uridan urinals (other urinals with sealant liquid have a similar maintenance routine) (source: Uridan).
19 19 Possibleadvantagesofsealantliquidsystemsinthecontextofdevelopingcountriesmayinclude:ÿ Noneedtobeexchangedwhenfullwithprecipitates,
butcanbeeasilycleaned.ÿ Afterbeingcleaned,theycanberefilledwithsome
thickcookingoil16(thisdoesnotlastaslongastherecommendedliquid,butisavailablealmostanywhere).
Thereisnoclearevidenceyetwhichofthethreesystemsdis-cussedaboveisbetterforlow-cost,low-maintenanceapplica-tions,andthismaydependonthepreferenceoftheindividu-alsorcompaniesresponsiblefortheurinals’maintenance.
4.4.4 Other methods for the odour seal
Othermethodsforodourcontrolareonthemarket(see also suppliers listing in Appendix).OneexampleisthesystembyUrimatwherethesealantliquidisreplacedbyafloat(hy-drostaticfloatbarrier)whichismagneticallyactivatedthusopeningthechanneltotheoverflowchamber.Forlow-costapplicationsindevelopingcountries,thissystemhasthedis-advantageofahighercomplexitycomparedtothesystemsdescribedabove17.
Small-scalesimplesystemsmayutilisejustapipeorhose(with-outanyodourtrap)connectingtheurinalwiththetank.Here,theodourcanbecontrolledbyhavingtheurinepipe(fillinghose)goingdowntoalmostthebottomofthecollectionvessel,thuscreatingaliquidsealinthecollectionvessel.Anotherop-tionistopoursomecookingoilintothecollectionvessel,thuscreatingathinsealantfilminthecollectionvesselitself.Acut-offcondomontheurineoutletpipehasalsobeenused.
Anotherverysimpleoptionforawaterlessurinalisthe“eco-lily”,whereaplasticfunnelisinsertedintotheopeningofaplasticjerrycan.Anoldlightbulboratabletennisballisplacedintothefunneltoactasodourseal(itshouldfloatupwhenurineentersthefunnelbutcouldendupstickingtothefunnel).Thedisadvantageofthelightbulbovertheplasticballisthatthesolderandmetalcaponthelightbulbcontainsheavymetalswhichcancontaminatetheurine.
4.5 Further design information
Thespacerequirementofaurinalislessthanthatofatoi-let,whichmakesthempopularforanyvenuewheremanymenneedtourinate(soccerstadiums,restaurants,schools,etc.).Waterlessurinalsareusuallywallhunganddonotrequirepipingforflushwaternorflushingdevices,thusallowingaconsiderablecostsaving.Theflushingdevicesaswellasthetraditionalwatertrapsintheoutletpiping(U,Por“bottle”shaped)ofconventionalurinalstendtoattractaconsiderableamountofvandalism(hencewaterlessurinalscanfurtherre-
ducemaintenancecosts).Waterlessurinalsdonotneedtobeconnectedtoasewerbutcanbeconnectedtoaurinestoragetankinstead(importantforremotelocationsnotconnectedtosewers).Obviously,waterforhandwashbasinsandwater-f lushedtoilets(ifnotreplacedbywaterlesstoilets)isstillrequirednexttothewaterlessurinals.
MaterialsUrinalbowlsaretypicallymadeofacrylic,ceramic,stainlesssteelorglass-fibrereinforcedpolyester,butcanalsobemadeofsimplelow-costplastic,providedthatithasasmoothsur-face(forodourcontrol).Self-constructionofinexpensivewaterlessurinalsisalsopossible.Whenusingplasticurinalbowls,oneoptionistouselinearlowdensitypolypropyleneasitisoneofthemostinertplastics(non-sticksurfaces).Thehotproductionprocessat180°Cguaranteesasmooth,non-poroussurface,thereforeminimisingbacterialbiofilmgrowth.
Converting water-flushed urinals to waterless urinalsItisinprinciplealsopossibletoconvertconventionalwater-flushedurinalstowaterlessurinals(dependingonthebowldesign),forexamplebyusingtheESS,whichisalsosoldasastandaloneunit.ItisveryimportanttogetasnugfitoftheESSintotheurinaldrain.
4.6 Use and maintenance of waterless urinals
Theinstructionsgivenbelowarenotforurinalsathouse-holdsbutforinstallationsatinstitutionsorpublicplaces18.Athouseholdlevel,differentmaintenanceroutinesapplythanthosedescribedbelowduetomuchlowerfrequencyofuse.Theurinalbowlshouldbecleaneddaily,justlikeanyother(water-flushed)urinal.Thereare100%biodegradableclea-ningsolutionsonthemarketthataresimplysprayedontotheurinalbowlandnotwipedoff.Forexample,URIMATMB-AktivReinigerwithtensidesisusedforthe50waterlessurinalsintheGIZheadquartersinEschborn,Germany.
15 ThecompanyF.ErnstIngenieurAGusedthesealantliquidsys-tem(initswaterlessurinalsinstalledmostlyinSwitzerlandandGerma-ny),butchangedovertotheEcoSmellstopsysteminOctober2006,andisnowretrofittingallofitsapprox.100,000urinalswhichwereinstalledpriortothatdate(F.ErnstAGoperatesitsurinalsunderamaintenancecontractshouldtheclientnotdecideotherwise).16 HakanJönsson:“the important properties of oil for this use are density lower than water - most oils have a density around 0.7 kg/L - this way it floats on urine; hydrophobic - maintains a lid above the urine and its content; and both of these are shared by cooking oils. Cooking oils are partly unsaturated and will thus oxidise faster and need replacement, but this is secondary to them being generally available”.17 HansKellerusedtorunthecompanyUrimatandhasthepat-ents.ButhenowrunsKellerInventwhichboughtFErnstAG(henceMr.KellermovedfromhydrostaticfloatbarriertoESS).18 Incountrieswithwide-spreadsewersystems,urinalsarenotusedathouseholdlevel.Butincountrieswhereonsitesanitationiscom-mon,waterlessurinalsathouseholdlevelareusedtogetherwithurinedi-versiondehydrationtoilets.
2020 Anytypeofodourseal(beitflatrubbertube,curtainsealorsealantliquid)needstobecleaned(orreplacedifcleaningisnolongerpossible)atregularintervalstokeepitfullyfunc-tional.Thefrequencyofcleaningorreplacementoftheodoursealsystemdependsmainlyonthenumberofusesperdayaswellasuserandcleaningstaffbehaviour(intermsofforeignobjectsdiscardedinurinal).Itcanthereforevarywidely,rangingfromonceaweektoonceeverysixmonths.
TheflatrubbertubeandESSunitscanbecleanedmanytimesbeforehavingtobereplaced.Somesealantliquidcartridgescannotbecleanedbutneedtobereplacedwhentheyfail,whilstforexampletheUridansystemcanbecleaned,andthesealantliquidreplaced,anynumberoftimes.Togiveanexample:AccordingtoinformationgivenbyAddicom,anESSelementcanlastfor16monthswithcarefulmaintenance,suchassprayingtheurinalbowlregularlywiththecleaningagent“DestroySmell”(containingtensidesandactivemicroorganisms),andremovingtheESSelementandrinsingwithdilutedcitricacidtoslowdowntheformationofurineprecipitatesonthecurtains.
Empiricalevidencegatheredinlow-incomesettingsinSouthAfrica(suchaspublicparksandtaxiranksinJohannesburg)since2004suggeststhatthecurtainseal(ESSsystem)canperformwithless maintenance thantheflatrubbertube.Inregionswherediligentmaintenanceofurinalscannotbegua-ranteed(suchaspublictoiletsininformalsettlementsinsub-SaharanAfrica),theESSsystemmaythereforebeabetterchoiceofthetwo.Moreside-by-sidecomparisonsbetweendifferentwaterlessurinaltypesarerequired,particularlyforurban,low-incomeareasindevelopingcountrieswithapoten-tiallyhighlevelofabuseandneglect.
4.7 User acceptance of waterless urinals
Experienceworldwidehasshownthatwaterlessurinalsen-joythesamelevelofuseracceptanceaswater-flushedurinalsdo,sinceforthemaleusersthereisnobehaviourchangere-quired(manyusersdonotevennoticethattheyareusingawaterlessurinal).Forthosemenwhoareshyanddonotlikeusingurinalsinpublicplaces(forlackofprivacy),itmakesnodifferencewhethertheurinaliswater-flushedornot.
Incultureswhereanalwashingwithwaterispracticed,eachurinalcanbeinstalledinacubicletoguaranteeprivacy.Forexample,manyMuslimmaleswashtheirgenitalswithwaterafterurinating,whichrequireswatersupplyandseparatedrai-nagefacilities.Priortoprovidingwaterlessurinals,onehastoestablishwhetherthecommunityinquestioniswillingtoacceptsuchfacilities.Notealsothatinsomeculturesmenareusedtosquattingwhenurinating.Waterlessurinalscouldbeplacedonthegroundinsteadofbeingwall-hung.
Insomeinstances,theremaybeapsychologicalbarrierofusersorcleaningstaff(“if a urinal is not flushed it cannot be hy gie-nic”).Thethoughtthatwaterisalwaysequaltohygieneisanunderstandablemisconception.However,whenfacedwithawell-functioning,odourlesswaterlessurinal,thosefearsarequicklyalleviated,whichiswhydemonstrationprojectscanbeuseful.Today’swaterlessurinalsaredesignedtobeodour-lessandsimpletomaintain.
Aswaterlessurinalsareanoveltyformanypeople,anysmellemittedfromawaterlessurinalgetsblamedonthenewsystem.Howeverasmellywater-flushedurinalisacceptedasnormalastheyhavealongodoroushistory.Itisafactthatanytypeofurinal(water-flushedorwaterless)willnotsmellifwellmaintained.Theextentofmaintenancerequiredforwater-lessurinalscanbehigherorlowercomparedtowater-flushedurinals,dependingonthetypeofwaterlessurinalused(asexplainedabove).
4.8 Suppliers and costs of waterless urinals
Thefollowingoptionsexistforbuyingwaterlessurinalsindevelopingcountries:ÿ Importedwaterlessurinalswithorwithoutpatented
odourcontroldevicesÿ Plasticwaterlessurinalsmanufacturedlocallyand
importedESSelementorliquidsealinsertedforodourcontrol
ÿ Self-constructedwaterlessurinalsmadefromplasticcontainers.
Forlowcostapplications,simpleplasticurinalsmaybeagoodoption.Thesecanbeproducedina"rotationmoulding"pro-cess.Thisisacheapandsimpleprocesstomakeasingle-skintypeunit,whichcanbereplicatedinanycountry.
SupplierslistsforwaterlessurinalsareprovidedintheAppendix. Forreferenceinstallationseithercontactthemanufacturersorseethecasestudydescriptionsofsustainablesanitationprojectsonwww.susana.org.Manyoftheseprojectsincorpo-ratewaterlessurinals.Photosofwaterlessurinalsarealsoavailablehere:http://www.flickr.com/photos/gtzecosan/sets/72157613881735035/
4.9 How to choose the right type of waterless urinal
Whenchoosingawaterlessurinalfromthelargerangeofsuppliersandmodels,thefollowingguidequestionscanbeused(forwaterlessurinalsininstitutionsandpublicplaces19):1. Dotheurinalsneedtobeascheapaspossible?2. Dotheuserspreferceramicurinalsoverplasticurinals?
19 Note:Forwaterlessurinalsathouseholds,themaintenancecon-siderationsarequitedifferent.Householdswanttousemaintenancema-terialsthatcanbefoundinageneralstoreataminimalcost.
21 21 3. Aretheurinalsavailablelocally(localdistributor)ordotheyhavetobeimported?
4. Doesthesupplierofferyoutogetincontactwiththesuppliers’existingclients?
5. Doesthesupplierhavereferenceletters?6. Howmanyunitshasthesuppliersoldalready?7. Dotheurinalsneedsparepartsandcantheybe
obtainedlocallywithminimalwaitingtimes?8. Istherelikelytobeanyvandalisminthelocation
wheretheurinalswillbeinstalled?9. Whowilldothemaintenanceandwilltheybe
diligentorratherunreliable?10. Afterhowmanyusesdoestheodoursealneed
replacement(orafterwhattimeperiod)?11. Howlongdoeseacheventofodourseal
replacementtake?12. Howdifficultistheodoursealreplacementroutine?
5 Urine diversion toilets
5.1 Definition
Urinediversion(UD)toiletsaredesignedtonotmixurineandfaecesatthepointofcollectioninthetoilet.TherearetwomainmaintypesofUDtoiletsandbothtypescanbebuiltindoors:1. Urine diversion dehydration toilets (UDDTs) Noflushwaterisused.Thesetoiletsareoftencalled
“ecosan toilets”butthiswouldwronglylabeloneparticulartoilettypeasthe toilettobeusedinecosanprojects.
2. UD flush toilets Waterisusedtoflushthefaecesawayandto
rinsetheurinecompartment.
Thesetoiletsmaybeimplementedwithinnewsanitationsystemsormaycomplementexistingsystems.Inanycase,additionalpipeworksuchasapipefromthetoiletstotheurinestoragetanksbecomesnecessary(see Section 6).
5.2 Basic design information for UD toilets
CarefulplanningandappropriatedesignisessentialforsuccessfulapplicationofUDtoilets.Theyshouldbedesignedorchosenbasedontheneedsandthecustomsoftheusers.Thepreferredpostureoftheusercanbe:ÿ Sitting toilets (withpedestals):
thesecanbewall-hungorfloormounted;orÿ Squatting toilets(withsquattingpans):manypeople
areusedtotoiletswhichareusedinasquattingposition.
FurtherdesignconsiderationswhichareimportantforalltypesofUDtoilets(detailsareprovidedinSection 5.3 and 5.4):1. Dotheuserswashtheiranalareawithwaterafter
usingthetoiletsordotheyusetoiletpaper(“washers”asopposedto“wipers”)?ThisiscustomaryinmanyMuslimandBuddhistculturesbutmayalsobelinkedtofactorsotherthanreligion.
2. Needsofdisabledpeople,elderly,childrenwhenusingthetoilet
3. Specificneedsoffemales(menstrualhygiene;privacyandsecurityneeds)
4. Odourcontrolfortheurinecollectionsystem5. Willthetoiletbeanindoororanoutdoortoilet
(indoorislikelytobecomethenorminthefutureandispossiblewithUDtoilets)?
5.3 Urine diversion dehydration toilets (UDDTs)
ThissectiononUDDTscontainsonlybasicinformation.Formoreinformationonthisimportanttechnologyanditsoperationandmaintenancerequirementssee:ÿ TechnologyreviewonUDDTsbyGIZ(http://www.gtz.de/en/themen/umwelt-infrastruktur/
wasser/9397.htm)ÿ BergerandLorenz-Ladener(2008);Morgan(2007);
Austin(2006);Kvarnströmetal.(2006);WinbladandSimpson-Hebert(2004)
ThebenefitsofUDDTscomparedtopitlatrineswerelistedinSection 2.3.2.
5.3.1 Basic design information
UDDTsdonotusewaterforflushing.Theyuseaverysim-plesystemwheretheurineiscapturedinabowlwhichisintegratedinthefrontofthetoiletpedestalorsquattingpan.Fromhere,theurineisdrainedofftoastoragecontainer.
Forthefaeces,astraightdrop(orchuteiftoiletsareonseve-rallevelsinthehouse)isprovidedfromthetoiletpedestalorsquattingpantoacollectionvaultorbin.
Aventpipeisprovidedtoventilatethefaeceschamber,removeodourfromtheroomandtospeedupthedryingprocess.UDDTsarenot designedforcompostingtotakeplaceinthefaecesvaultbutjustfordrying.
Inregionswherepeoplepractiseanalcleansingwithwater,athirdoutletholeisused,tocollectandtreattheanalwashwaterseparatelyfromurineandfaeces(see Figure 5).Itisbestnottomixanalwashwaterwithurinetokeeppathogenlevelsintheurineataminimum,ifurineistobeusedasafertiliser.
2222 Theanalwashwatercanbeinfiltratedinagravelfilterortreatedtogetherwithgreywaterinasubsurfaceconstructedwetland.UDDTsareespeciallypopularwhereverthereiswaterscarcityandademandforcheapfertiliser.Theycanbebuiltindoorsoroutdoors.
5.3.2 Odour control for urine collection system
Anodoursealmaybeusedontheurinepipeifthetoiletisindoors,especiallyinsystemswithmanytoilets(thesametypesofsealsasforwaterlessurinalscanbeused,includingtheESS(see Section 4.3)).SomeUDDTsevenhaveaninte-gratedfan(suchasthetoiletofSeparett),whichremovesodourfromboththefaecesbucketandtheurinepipe.Noseparateodourblockingdeviceisnecessaryinthiscase.
ForoutdoorUDDTswithindividualurinestoragetanks,theconnectiontotheurinestoragetankisusuallydirect,with-outanyodourtrappingdevice.Thefaeceschamberhasaventpipetoremoveodourfromthetoilet,anddryadditivesassistinodourcontrol.
5.3.3 Construction methods and materials
Possiblematerialsforthetoiletpedestalorsquattingpanare:ceramic,concrete,acrylicorglass-fibrereinforcedplastic.Thetoiletcaneitherbeself-constructedorprefabricated.Metalcomponents(exceptforstainlesssteel)cannotbeusedsinceurineiscorrosive.
5.3.4 Use and maintenance ThemainoperationalrequirementwhenusingUDDTsisthatthefaecesvaultiskeptasdryaspossible(noadditionofurineorwater).Theurineandfaecescontainersneedtobeemptiedwhenfull.
Coveringmaterialshouldbeaddedtothefaecesvaultaftereachdefecation.Coveringmaterialcanbeash,sand,soil,lime,leavesorcompostandshouldbeasdryaspossible.Thepurposeofaddingcoveringmaterialisto:ÿ reduceodourÿ assistindryingofthefaeces(tosoakupexcessmoisture)ÿ preventaccessforfliestofaecesÿ improveaestheticsofthefaecespile(fornextuser)ÿ increasepHvalue(achievedwhenlimeorashisused).
5.3.5 Project examples
UDDTsareusedinmanyruralandurbansustainablesanitationprojectsworldwide.Theyhavebeeninstalledathouseholds,schools,prisons,universitiesetc.andforpublictoilets(seeforexampleSuSanAcasestudieson:http://www.susana.org/lang-en/case-studies).
5.4 UD flush toilets5.4.1 Overview on historical development
UDflushtoiletswereinventedinSwedeninthe1990’s(Kvarnströmetal.,2006).Theywerefirstadoptedineco-villagesandholidayhomes.Today,theyarealsousedinsomehousingprojectsandpublicbuildingsinseveralcountriesinEurope,althoughstillonlyatapilotscale.Adetailedstudy(calledNOVAQUATIS)onUDflushtoiletswasconductedbyEawag,Switzerland(LarsenandLienert,2007).
5.4.2 Basic design information
ThebenefitsofUDflushtoiletscomparedtoflushtoiletswerelistedinSection 2.3.1.TheUDflushtoilethasaparti-tioninthetoiletbowlisolatingabowlforurineinthefront,andabowlforfaecesintheback.ThebowlissimilartobowlsusedforUDDTs,exceptthatfortheUDflushtoilet,waterisusedtoflushthefaecesaway.Theflushingmechanismfortheurinepartisdesignedinoneoftwoways:1. Theurinepipestaysopenandthereforereceivesa
certainamountofflushingwaterwhenthebowlisflushed(see Figure 6);or
2. theurinepipeisclosedbyavalveandthereforereceivesnoflushingwater(thisisthecasefortheRoedigerNoMixtoilets).
Figure 5. left: Indoor UDDT (pedestal type) in Johannesburg, South Africa in the house of Richard Holden (source: E. v. Münch, 2006).Right: UDDT squatting pan in Bangalore, India, with three holes: the area in the front is for anal washing, middle is for faeces and back is for urine (source: D. Schäfer, 2008).
23 23 TheUDflushtoiletscanreducewaterconsumptioncom-paredtoconventionalwater-flushedtoiletsbecausethewaterrequiredforthe“urine flush”islessthantheamountforthe“ faeces flush”.
UDflushtoiletscanalsobecombinedwiththeconceptofvacuumtoilets(realisedforexamplebythecompanyRoedi-gerforapilotprojectinBerlinStahnsdorfandbytheSwe-dishcompanyWostManEcology,seeAppendix).Thistypeoftoiletcollectsurineandasmall,concentratedamountofbrownwater(faeceswithabout1Lofflushwater).
5.4.3 Odour control for the urine collection system
Fortheurinepipe,severaltypesofodoursealsareusedbythetoiletmanufacturers,suchasavalve(RoedigerNoMixtoi-lets),aurine/waterseal(Gustavsbergtoilets)oranovelsiliconseal(Dubblettentoilets).
OdourlocksintheUDtoilet’surinepipearerequiredtopre-ventbackflowofodourintothetoiletroom;butthesearenotnecessaryinthecaseofshorturinepipesystemsofupto3-4m.Forthefaecespart,odourcontrolisachievedbyawatersealinaU-bend(justlikeforconventionalflushtoilets).
5.4.4 Materials
AsUDflushtoiletshavebeendesignedforusersinhigh-incomecountries,theyhavebeenmanufacturedonlyincera-micandhaveasimilarappearancetoconventionalflushtoilets.
5.4.5 Use and maintenance
ThefaecessectionofUDflushtoiletsiscleanedinthesamewayasforconventionalf lushtoilets(withabrush).Toiletpaperisflushedawaytogetherwiththefaeces.
AparticularproblemfoundwiththeRoedigerNoMixtoiletisthattoiletpaperthrownintotheurinalbowlisnotflushedawaywiththesmallurineflush;andhencemorethanoneflushbecomesnecessary–negatingthewatersavingeffectofthistypeoftoilet20.
AnotherproblemoftheRoedigerNoMixtoiletisthatthevalveontheurinepipecangetblockedovertime.Inthiscase,urineisnolongercollectedinthestoragetankbutflowstothefaecessectionofthetoilet,orthevalveisnotclosinganymorecausingodourproblemsinthetoiletroom.Therefore,theuserneedstocarryoutpreventativemaintenancebyaddingdilutedcitricacidtothevalveoncepermonthforaperiodof24hours.
5.4.6 Project examples
UDflushtoiletsareusedinsomeindustrialisedcountriesandtheyarenotalowcostoption.SofartheyaremainlyusedinSwedenandinsomeprojectsinGermany,theNetherlands,SwitzerlandandAustria.
Twoprojectexamplesforwhichdetaileddescriptionsareavail-ableare(bothonhttp://www.susana.org/case-studies?showby=default&vbls=2&vbl_2=9&vbl_0=0):ÿ UrineandbrownwaterseparationattheGIZ
mainbuilding,Eschborn,Germanyÿ Urbanurinediversion&greywatertreatment
system,Linz,Austria
5.5 Suppliers and costs for UD toilets
InformationonmodelsandsupplierscanbefoundintheAppendix.Thecostsforsomeofthesetoiletsarerelativelyhigh,asthenumbersoldisquitelow.Ifthemarketforthesetypesoftoiletsgrowsandmoresuppliersenterthemarket,thentheunitcostswilldecline.
5.6 How to choose between a UDDT and a UD flush toilet
Forpro-poorapproachesindevelopingcountries,UDDTsaremoresuitablethanUDflushtoilets,asthelatterstillrequireareliable24-hourwatersupply,asewersystemandatreatmentprocessforthefaeces-watermixture(brownwater).
Incountrieswithexistinginfrastructureforwastewatertreat-ment,theUDflushtoiletmaybecomecompetitivewiththeconventionalflushtoiletinthefutureifthebenefitslistedinSection 2.3aredriversfortherequiredswitch.
Figure 6. UD flush toilets. Left: Gustavsberg (in Meppel, the Netherlands); Right: Dubbletten (in Stockholm, Sweden); (sources: E. v. Münch, 2007).
20 TheRoedigerNoMixtoiletisafirstprototypewhichrequiresfurtherdevelopmentofitsdesign.
2424 6 Urine piping and storage tanks
AcomprehensivedescriptionofthetechnicaldetailsforurinepipesandtanksisavailableinKvarnströmetal.(2006).Somekeyconsiderationsareprovidedbelow.
6.1 Urine piping6.1.1 Functional principles
TheurinepipingsystemconnectswaterlessurinalsortheurinesectionofaUDtoilettotheurinestoragetank.Asurinegeneratesaconsiderableamountofurineprecipitatesandsludge(see Section 2.4.4 for causes),specialattentionhastobepaidtothedesignandmaintenanceoftheurinepipingsystem.
6.1.2 Materials
Urinepipeworkisnormallymadeofdurableplasticssuchaspolyethylene(PE)orpolyvinylchloride(PVC).
6.1.3 Pipe size and layout
Tomaximisetheflowrateoftheurine(andanysediments),theinsidesofthepipesshouldbesmooth.Flowrestrictions,suchassharp90ºbends,shouldbeavoidedasmuchaspossible.
Theminimumrecommendeddiameterofthepipesis50mm,buttheoptimumrangeisfrom75mmto110mm.
Forlargersystems(severaltoiletsconnectedtooneurinetank),theslopeofthepipeshouldbeatleast1%tominimiseurineprecipitation.Forindividualtoiletsystems,theslopeshouldbeatleast4%,butcanbebuiltwithsmallerdiameterpipes,downtoabout15mm.
Forinspectionandcleaning,thepipesshouldbemadeaccessible(byprovisionofinspectionopenings).
Asaruleofthumb:keepurinepipesas short as possibleandwiththehighestpossibleslope.Horizontalpipesshouldnotexceed200mbecauseoftheproblemsofsludgeaccu-mulationinthecontinuouslywettedsideofthepipe21.
Overtimecrystalsandsludgemayaccumulateintheslowflowinghorizontalpartsofthepipesystem,soperiodicflush-ingmaybenecessary(onceeveryfewyearsinthebestcase;morefrequentintheworstcase)22.
6.1.4 Odour control
Topreventodours,thepipingsystemshouldbeonly spar-inglyventilated,pressureequalisationisenough(see Section 6.3 for more details on ventilation).Alsothepipeopeningneedstobeimmersedintotheliquidinthestoragetank.Thisisparti-cularlyimportantinlongventpipesthatcanactaschimneyswithupwardflowofair23.
Thismeansthattheincomingpipetotheurinestoragetankshouldgodownalmosttothebottom,sothataliquidsealisformedpreventingunduegasmovementthroughthepipingsystem.Butitisnotrecommendtoplaceabucketatthebaseofthispipe,asitmightfillwithsludgeandthusintroduceaflowrestriction.
6.2 Urine storage tanks6.2.1 Functional principles
Theurinewhichiscollectedbymeansofawaterlessurinalorbyaurinediversiontoiletflowstoaurinestoragetank.Thesetankshavealidandareclosedtopreventodourandlossofnitrogenviaammoniagas.Thetanksareeitheremptiedbytheusersthemselves(small-scalesystems)oremptiedbyapumpandtruckarrangement.Theurineisthentransportedtothepointofagriculturalreuseortofurtherstorageortreatment.
Urinestoragetankshaveoneorseveralofthefollowingthreemainpurposes:1. Tobridgethetimeinbetweencollection/emptying
events.2. Tosanitisetheurine:overtime,pathogensinthe
urinearekilledoff(increasedpHduetoureaconver-siontoammonia(see Section 2.7.2).
3. Tobridgeperiodswhereplantsarenotfertilised:Theplants’needforfertiliserisnotconstantallyearround(exceptinthetropics).Fertilisernutrientsaregenerallyonlyneededjustbeforesowingandinthebeginningofthegrowthperiod (see Section 3).
Therearetwotypesofurinetanks:thereceptorurinetankatthetoiletandtheurinestoragetankforstorage,sanitisationandreuse(thesefunctionscanberealisedinthesamevesselorinseparatevessels).
21 Source:ArnoRosemarin(March2009)22 HakanJönsson(March2009):“My fairly extensive experience is that as long as there is at least a slope of 1% and the diameter is 75 mm or more, then the sludge will flow out at the rate of generation and flushing is not necessary. The reason why extensive pipes should be avoided is that fre-quently there has been problems with groundwater leaking into the pipes, di-luting the urine!”23 Source:ArnoRosemarin,March2009,basedonexperiencewithlarge-scaleurinediversionsystemwithindoorUDDTsinErdos,China.
25 25 6.2.2 Locations
Thelocationoftheurinestoragetankscanbe:1. At toilet level:Iftheurineistobeusedinthehouse-
holdgarden,asimpleplasticjerrycancanbeused.2. At household/building level(severaltoiletstogether).3. At community level(severalhousestogether)–
thisispossibleifdistancesbetweenhousesareshort.
Astheurinetanksmustbeemptiedregularly,suitableaccessforpersonsorvehiclesisrequired.
Thetankscanbelocatedeitherinthecellarofthebuilding,nexttothebuildingorbelowground.Urinetanksbelowgroundhavethedisadvantagethatleaksfromtheurinetankaredifficulttodetect(aleakingurinestoragetankcanleadtogroundwaterpollutionwithammoniaandnitrateortothetankbeingfilledwithgroundwater).Undergroundtankshavetheadvantageshoweverthattheyareusuallycheapertobuild,haveabetterinsulationinwinter(relevantforcoldclimates)andtheaccesstothemanholeisusuallyalsoeasier.Inthecaseofundergroundtanksitisimportanttotakethegroundwaterlevelintoaccount–toavoidtanksfloatingintheeventofrisinggroundwater.
Whilstthetanksareclosedanddesignedtominimiseodour,someodourcouldstilloccur.Hence,thetanksshouldbeinawell-ventilatedareaandawayfromkitchens,officesandbedroomstominimiseodourcomplaints.
Asecondaryurinestoragetankatthefarmer’spremisesmaybenecessarytoenablethefarmerstoapplytheurinewhentheyneedit(Figure 8).
6.2.3 Materials
Urinestoragetanksneedtobecompletelywatertighttoavoidlossofurinefertiliser,groundwatercontaminationandgroundwaterentering.Theyaremostcommonlymadeofglassfibrereinforcedplastic,PE,PPorPVC,buttheycanalsobemadeofrubberbladdersorhigh-qualityreinforcedconcrete(thereareafairnumberofconcreteurinetanksinSweden,buttheyneedtobebuilttoahighstandardtoavoidleakages).
Metalcomponentscannotbeusedsinceurineiscorrosive(ex-ceptforstainlesssteel,whichcouldbeusedbutisexpensive).
Plastictankswhicharesoldforrainwaterharvestingarealsosuitableasurinestoragetanks,andcanbeagoodsolutionindevelopingcountries.
6.2.4 Urine tank size
Theurinetanksystemmaybesetuptouseonelargeurinestoragetankorseveralsmallertanks(evendowntousingalargenumberof20 Ljerrycans).Ineithercase,therequiredtotalstoragevolume(Vstorage)canbeestimatedasfollows(addi-tionalsafetyfactorsmaybeapplied):
Vstorage = Nusers · purine · tstorage·ftimefraction
with:Nusers =numberofuserspurine =specificurineproductionperperson
(~1.5 L/cap/dofurineiftheuserisatthepremises24hoursperday24)
tstorage =desiredstoragetime25ftimefraction =fractionoftimethattheusersstaysatthe
premiseswherethetoiletis.
Therequiredstoragetime(tstorage)wasalreadydiscussedinSection 2.7.2).Forexample,typicaldesigncriteriaforasto-ragetankare360Lofurineperpersonperyear(iftheyspend2/3oftheirtimeatthepremises)andastoragetimeofonemonth.
Itisobviousfromthisequationthatifurineisflushedawaywithwater,thenalargerurinestoragetankisrequiredcom-paredtoatoiletwhereurineiscollectedundiluted.
Whendesigningthesizeoftheurinestoragetank,considera-tionalsoneedstobegiventothecapacityoftheemptyingvehicle.Detailsonpossibleemptyingvehiclesinthelow-costcontextareprovidedinSlob(2006).
Iftransportationoccursmanually,thecollectiontanksshouldnotbelargerthan20 Lwhichequals20 kgwhenfull(thiswouldalreadybetooheavyfortheelderly,femalesandchildren).
6.2.5 Number of urine tanks needed
Forpropersanitisation(tokillpathogensoriginatingfromcross-contaminationwithfaeces)itisimportantthattheurineisstoredwithoutfreshurineenteringbeforeitisappliedinagriculture.Hence,atleasttwotanksarerecommended(are-ceptortankandastoragetank).
Forlargeinstallations,theuseofseveralurinestoragetanksisadvisablesothatonecanbetakenoutofserviceifnecessary.
24 PlusflushingwaterifUDflushtoiletsareused,unlesstheyhaveavalveliketheRoedigerNoMixtoiletmodel.25 Thiscouldalsobethedesiredtimebetweenemptyingeventsifsanitisationbystorageisnottheaim(forreceptortankwithadditionalstorageelsewhere).
2626
6.2.6 Urine overflow pipe
Installationofaurineoverflowpipeonthetankisnotrecommended,asthisincreasescostsandintroducesariskofcontaminationoftheurinewhenthereisanoverfloworblock-ageintheordinarywastewatersystem.Also,ifthereisanover-flowarrangement,usersmaybetemptedtojustlettheurineoverflowandnotensureitsuse.Itisbetterthattheurineispumpedtoanacceptabledisposalpointwithaportablewaste-waterpumpifthecollectiontankbecomestoofull.
6.2.7 Examples
Examplesforurinestoragetanksofdifferentsizesareshownbelow.
6.3 Ventilation for pressure equalisation of pipes and tanks
Thepipeandtanksystemshouldonlybepressureequal-ised(notventilated)whichisbestdonebyasmallholeinthetankforequalisationwiththeurinetankpressure.Thisal-lowsthereplacementofheadspaceairbyurineflowingintothetank,andviceversawhenemptyingthetank.
Thereasonswhythepipesystemshouldnotbeventilatedare:ÿ Toeliminateammoniaemissionsandodour.ÿ Toreduceriskofsuckingtheliquidoutofanyliquid
urinesealsintheUDtoilets.
Aone-wayvalveorairadmittancevalveplacedatthetopoftheventpipecanalsobeagoodoption.Advantagesofsuchavalveare26:1. thatammoniaisnotemitted,2. internalpressureisequalisedensuringproperdrainage
downwardstothetank(emptiedurinepipesmeannostandingurineandlessprecipitation),
3. theinstallationcanbedoneinsidethebuildingjustabovethetopfloorinthebuildingsothatthetopoftheventpipedoesnotneedtopenetratetheroof likeold-fashionedventilationpipes,
4. savesonconstructioncosts,5. eliminatesproblems causedbycondensationicein
coldclimatesandUVweatheringofplasticpipes.
Theseone-wayairvalvesarepopularinSwedenforgreywaterandurine systems,andmanynewhousesnolongerhavepro-trudingventpipes.
Theurinetankshouldnotbeopenedmoreoftenthanneces-saryinordertopreventodourdevelopmentandammonia-nitrogenlosses.Importantpointsconcerningthetank’sventilationsystemare:
Figure 7. Left: Low-cost solution: 20 L plastic jerrycan for urine storage at in-dividual toilet level in Ouagadougou, Burkina Faso (source: E. v. Münch, 2006). Note: it might be quite difficult to lift up a full jerrycan out of this enclosure. Right: Below-ground plastic urine storage tanks at Kullön, Sweden during the construction process. The tanks will be covered with soil (photo: Mats Johans son, source: Kvarnström et al., 2006).
Figure 8. Urine storage tank made of a 150 m³ plastic bladder at Lake Bornsjön near Stockholm, Sweden (photo comissioned by: E. v. Münch, 2007).
Figure 9. Plastic urine storage tank in Ouagadougou, Burkina Faso as part of the EU-funded project ECOSAN_UE led by CREPA (source: S. Rüd, 2008).
26 PostingbyArnoRosemarin(SEI,Sweden)onEcosanresdiscus-sionforum,August2008.
27 27 ÿ Normallynoventpipeisneeded,providedthatthemainopeningisnotverytightlysealed.
ÿ Inplaceswhereodourcontrolisessential,asmalldiameterventpipecanbeusedforpressureequalisa-tionofthetank.
ÿ Ifthetankisemptiedbyapump,provisionsshouldbemadeforsufficientflowofairintothetank.Thispre-ventsexcessivevacuuminthetank,whichcancausetankimplosion.
6.4 Maintenance of urine pipes and tanks
Itisdifficulttopredicthowfrequentlypre-emptivemain-tenanceshouldbecarriedoutasthisdependsonlocalcircum-stances.Trialanderrorwillleadtoanoptimisedcleaningschedule.Experiencehasshownthatcorrectlyinstalledpipesgenerallyneednocleaning,exceptfortheodoursealor90°bends(whichshouldbeavoided).
DetailedinstructionsforcleaningandpreventingblockagesinU-bendodoursealsareprovidedinKvarnströmetal.(2006),fromwherethefollowingparagraphsaretaken:“In all installations there is a risk of blockages occurring mainly in the odour seal in the urine pipe. It is a result of fibres and other particles entering the piping system and of chemical precipitation of struvite and calcium phosphates from the urine caused by the increase in pH which occurs when its urea is degraded. The pre-cipitation also forms a viscous sludge, which will slowly flow to-wards the tank provided that the slope of the pipes is correct.
Most blockages that occur in urine-diverting toilets are soft block-ages caused by precipitation on hair and paper fibre. The other type is hard blockages, caused by precipitation directly on the pipe wall27. The blockages are removed either mechanically by a drain auger or chemically by use of strong solutions of caustic soda (2 parts of water to 1 part of soda) or acetic acid (>24%).”
Itisimportantthatthecleaningiscarriedoutwithoutaffect-ingthequalityoftheurineintheurinestoragetanksisnotnegativelyaffected.
Iftheurinecanflowfreelyandimmediatelywithoutaddi-tionsofwaterdirectlyafterurinationtothestoragetank,thennoorveryfewblockagesinthepipewilloccur.
Atthebottomoftheurinestoragetankalayerofsludgeformsovertime(containingprecipitatesandcrystals–see Section 2.4.4 ),withhighlevelsofnitrogen,phosphorus,calciumandmagnesium.Ifthefullnutrientvalueofurineistobeusedforfertiliserpurposes,thenitneedstobeen-suredthatalsothebottomsludgelayerisemptiedandreused.Incompleteemptyingwouldalsoresultinreducedavailablestoragevolume.
7 References
7.1 References used in this document Austin,L.M.(2006)Guidelinesforthedesign,operationandmaintenanceofurinediversionsanitationsystems,Volume4,ReporttotheWaterResearchCommission,WRCTT275/06,SouthAfrica,http://www2.gtz.de/dokumente/oe44/ecosan/en-guidelines-urine-diversion-sanitation-systems-2006.pdf
Berger,W.andLorenz-Ladener,C.(2008)Kompost-Toiletten–SanitärtechnikohneWasser(inGerman).ÖkobuchVerlag,StaufenbeiFreiburg,Germany(www.oekobuch.de).Tableofcontents:http://www2.gtz.de/Dokumente/oe44/ecosan/de-TOC-ONLY-kompost-toiletten-ohne-wasser-2008.pdf
Cordell,D.,Schmid-Neset,T.,White,S.andDrangert,J.-O.(2009)Preferredfuturephosphorusscenarios:aframeworkformeetinglong-termphosphorusneedsforglobalfoodde-mand.InternationalConferenceonNutrientRecoveryfromWastewaterStreams,Vancouver,Canada,May2009,http://www2.gtz.de/Dokumente/oe44/ecosan/en-preferred-future-phosphorus-scenarios-2009.pdf
EcoSanRes(2008)Closingthelooponphosphorus,EcoSan-ResFactsheet4,StockholmEnvironmentInstitute,Stock-holm,Sweden,http://www.ecosanres.org/pdf_files/ESR-factsheet-04.pdfGensch,R.,Miso,A.andItchon,G.(2011)UrineasliquidfertiliserinagriculturalproductioninthePhilippines–Apracticalfieldguide.XavierUniversityPress,Philippines,http://www.susana.org/lang-en/library?view=ccbktypeitem&type=2&id=1168
Jönsson,H.,RichertStintzing,A.,Vinnerås,B.andSalo-mon,E.(2004)Guidelinesontheuseofurineandfaecesincropproduction,EcoSanResPublicationsSeries,Report2004-2,Sweden,www.ecosanres.org/pdf_files/ESR_Publications_2004/ESR2web.pdf
Kvarnström,E.,Emilsson,K.,RichertStintzing,A.,Johans-son,M.,Jönsson,H.,afPetersens,E.,Schönning,C.,Chris-tensen,J.,Hellström,D.,Qvarnström,L.,Ridderstolpe,P.andDrangert,J.-O.(2006)UrineDiversion - OneStepTowardsSustainableSanitation.Report2006-1,EcoSanResProgramme,StockholmEnvironmentInstitute,Stockholm,Sweden,http://www.ecosanres.org/pdf_files/Urine_Diversion_2006-1.pdf
Larsen,T.A.andLienert,J.(2007)Novaquatisfinalreport.NoMix–Anewapproachtourbanwatermanagement.Eawag,Dübendorf,Switzerland,www.novaquatis.eawag.ch/publikationen/final_report_E
27 Hardblockagestendtooccurwhenwaterismixedwithurine,whereassoftblockagestendtooccurinpureurinesystems.
2828 Maurer,M.(2007)Urinetreatment–absoluteflexibility,EawagNews,March2007,resultsfromNovaquatisresearchproject,Dübendorf,Switzerland,http://www2.gtz.de/Dokumente/oe44/ecosan/en-urine-treatment-absolute-flexibility-2007.pdf
Maurer,M.,Schwegler,P.andLarsen,T.A.(2003)Nutrientsinurine:energeticaspectsofremovalandrecovery.Water Science and Technology,48(1),p.37-46.Abstractavailablehere:http://www2.gtz.de/Dokumente/oe44/ecosan/en-ABSTRACT-ONLY-nutrients-in-urine-energetic-aspects-of-removal-and-2003.pdf
Morgan,P.(2007)ToiletsThatMakeCompost-Low-cost,sanitarytoiletsthatproducevaluablecompostforcropsinanAfricancontext,StockholmEnvironmentInstitute,EcoSanResProgramme,Stockholm,Sweden,http://www.ecosanres.org/toilets_that_make_compost.htm
Münch,E.v.andDahm,P.(2009)Waterlessurinals:apro-posaltosavewaterandrecoverurinenutrientsinAfrica.34thWEDCInternationalConference,AddisAbaba,Ethiopia,May2009,http://www2.gtz.de/Dokumente/oe44/ecosan/en-waterless-urinals-a-proposal-to-save-water-and-recover-urine-nutrients-in-africa-2009.pdf
Richert,A.,Gensch,R.,Joensson,H.,Stenstroem,T.andDagerskog,L.(2010)Practicalguidanceontheuseofurineincropproduction.StockholmEnvironmentInstitute(SEI),Sweden,http://www.susana.org/lang-en/library?view=ccbktypeitem&type=2&id=757
Rosemarin,A.,Ekane,N.,Caldwell,I.,Kvarnström,E.,McConville,J.,Ruben,C.andFogde,M.(2008)PathwaysforSustainableSanitation-AchievingtheMillenniumDevelopmentGoals.SEI/IWA.Availablefororderfrom:www.ecosanres.org.Tableofcontentsavailablehere:http://www2.gtz.de/Dokumente/oe44/ecosan/en-TOC-ONLY-pathways-for-sustainable-sanitation-2008.pdf
Schönning,C.andStenström,T.-A.(2004)Guidelinesforthesafeuseofurineandfaecesinecologicalsanitationsystems,EcoSanResPublicationsSeries,Report2004-1,www.ecosanres.org/pdf_files/ESR_Publications_2004/ESR1web.pdf
Slob,M.(2005)Logisticaspectsofecologicalsanitationinurbanareas.Casestudyinlow-incomecommunityinDelhi,India.MScThesis,UniversityofTwente,TheNetherlandsandWASTE,Gouda,http://www2.gtz.de/Dokumente/oe44/ecosan/en-logistic-aspects-of-ecological-sanitation-2005.pdfSuSanA(2008)Foodsecurityandproductivesanitationsystems.FactsheetofSustainableSanitationAlliance,http://www.susana.org/lang-en/library/rm-susana-publications?view=ccbktypeitem&type=2&id=101
Tettenborn,F.,Behrendt,J.andOtterpohl,R.(2007)Resourcerecoveryandremovalofpharmaceuticalresidues-Treatmentofseparatecollectedurine.Finalreportofthedemonstrationproject"SanitationConceptsforSeparateTreatmentofUrine,FaecesandGreywater"(SCST).InstituteofWastewaterMan-agementandWaterProtection,HamburgUniversityofTech-nology,Germany,http://www.tu-harburg.de/t3resources/aww/publikationen/pdf/endbericht_tutech151009.pdf
Udert,K.,Larsen,T.,Biebow,M.,Gujer,W.(2003)Ureahydrolysisandprecipitationdynamicsinaurine-collectingsystem.WaterResearch37(11),p.2571-2582.http://www2.gtz.de/Dokumente/oe44/ecosan/en-urea-hydrolysis-precipita-tion-dynamics-urine-collecting-system-2003.pdfUdert,K.,Larsen,T.andGujer,W.(2006)Fateofmajorcompoundsinsource-separatedurine.WaterScienceandTechnology54(11-12),p.413-420.http://www.iwaponline.com/wst/05411/wst054110413.htm
WHO(2006)WHOGuidelinesfortheSafeUseofWaste-water,ExcretaandGreywater.Volume4:Excretaandgrey-wateruseinagriculture.WorldHealthOrganisation,Geneva,Switzerland,http://www.who.int/water_sanitation_health/wastewater/gsuweg4/en/index.html
Winblad,U.andSimpson-Hébert,M.(2004)EcologicalSanitation - revisedandenlargededition.StockholmEnvi-ronmentInstitute,Stockholm,Sweden,www.ecosanres.org/pdf_files/Ecological_Sanitation_2004.pdf
Winker,M.(2009)Pharmaceuticalresiduesinurineandpo-tentialrisksrelatedtousageasfertiliserinagriculture,PhDthesis,TechnicalUniversityofHamburg-Harburg,InstituteofWastewaterManagementandWaterProtection,Germany,http://doku.b.tu-harburg.de/volltexte/2009/557
Winker,M.andHartmann,M.(2010)UrineandbrownwaterseparationatGTZmainofficebuildingEschborn,Germany.Casestudyofsustainablesanitationprojects.SustainableSani-tationAlliance,http://www.susana.org/lang-en/case-studies?view= ccbktypeitem&type=2&id=63
Winker,M.,Vinnerås,B.,Arnold,U.,Muskulos,A.andClemens,J.(2008)Newfertilisersfromadvancedwastewatertreatment:Theirpotentialvaluesandrisks.In:Proceedingsof13thRAMIRANInternationalConference,Potentialforsimpletechnologysolutionsinorganicmanuremanagement,June2008,Albena,Bulgaria,http://www.susana.org/lang-en/library?view=ccbktypeitem&type=2&id=1008
29 29 7.2 Video clips
Manyvideoclipsshowingurinediversiontechnologiesareavailableviavideosharingwebsites(suchasYoutubeorVimeo).Thesecanbeaccessedvia:ÿ SuSanA’sYoutubechannel:
www.youtube.com/susanavideosÿ SuSanAwebsite:www.susana.org/videos-and-photos/
resource-material-video
7.3 Additional photos
Wehaveuploadedalargenumberofphotosonurinedi-versioncomponentstothephotosharingwebsiteFlickr.com.Youfindphotosofwaterlessurinals,urinediversiontoilets(pedestalsorsquattingpans,dryorwithflushing)inthe“technologycollection”here:http://www.flickr.com/photos/gtzecosan/collections/72157626218059440/
8 Appendix
Worldwide listing of suppliers for waterless urinals, UDpedestals and squatting pans
TheAppendixisprovidedinseparatefilestokeepthefilesizelowandissortedalongthedifferenttypesofurinalsandtoilets.ÿ Appendix 1:Worldwidelistingofsuppliersforwater-
lessurinalsÿ Appendix 2:Worldwidelistingofsuppliersforurine
diversionsquattingpans(forUDDTsorforurinedi-versionflushtoilets)
ÿ Appendix 3:Worldwidelistingofsuppliersforurinediversionpedestals/seats(forUDDTsorforUDflushtoilets)
Allthreefilesareavailablehere:http://www.susana.org/lang-en/library?search=appendix