Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Alternative Water Resources Cluster
Alternative Water Resources: A Review of Concepts, Solutions and Experiences
Alternative Water Resources Cluster
Alternative Water Resources Cluster
International Water Association
2015
AlteRnAtive WAteR ResouRCes: A RevieW of ConCepts, solutions
And expeRienCes
Main authorsDevon Hardy
Francisco Cubillo
Mooyoung Han
Hong Li
Key Contributors And ReviewersHelena Alegre
Bambos Charalambous
Israel García
Raül Glotzbach
Jan Hofman
Valentina Lazarova
Walter Malacrida
Patricia Gómez Martínez
Tim Waldron
Xiaochang Wang
PREFACEEvery resource used to supply water demand in an urban zone could be considered as alternative. Historically, since
settlements were located some distance from water sources, a variety of sources and technologies for abstraction,
conveyance, treatment and waste collection were emerging. Population growth and evolving enabling technologies led to
new forms of alternative resources that were able to satisfy needs and specific requirements for water related activities. At
the beginning, solutions were mainly focused on looking for additional reliable and good quality raw water resources without
considering that large infrastructures were required to abstract, store and convey water to consumption points. Since cities
and water demands were growing, potential solutions became more expensive, with high marginal costs and significant
environmental impact. In some cases these solutions were just unfeasible or created considerable social reluctance.
All over the world, the search for affordable, acceptable and reliable solutions is today a common challenge for water
supply planners. Therefore, having a sufficient quantity of water with appropriate quality is a common aim.
In this context, the water sector has been coping with different concerns throughout time. This way, finding average
demand/resources balance was the first concern, especially for water-stressed areas. Then, reliability of available resources
under droughts or scarcity scenarios became the key issue to cope with climate variability. Appropriate water quality for
health protection and to fulfil specific requirements of every use was the following challenge. Thus, technology has been
providing solutions to every problem, contextualised with different costs, impacts and consequences. Nowadays, some
solutions such as desalination, reuse, greywater, artificial recharge or rain harvesting could be considered almost as
conventional solutions as abstraction from pure streams or aquifers was long ago. There are many examples of use of those
resources and their enabling technologies.
Additionally, demand management is the other component of resources/demand balance, and, in consequence, its
contribution should be also analysed. If demand is considered as the total water that outflows from a water supply system,
demand management must include policies to reduce both the global consumption and the different types of real loss.
Every context and city has a variety of options with different figures of marginal costs, (economic, social and
environmental) and with different reliability for the availability/demand balance.
A review of the mentioned alternative options that focus on resources and demand has been compiled and described in
detail in this Compendium. Likewise, case studies and parameters to assess their costs and benefits are described.
This Compendium is a good starting point for the activities planned in IWA’s Alternative Water Resources Cluster. There
are many identified ways to move forward within the cluster: new solutions for appropriate water balance, such as water
trading, cloud stimulation, and applications of other smart technologies, new methods to assess reliability and to include risk
parameters and principles, new criteria to compare in a consistent way potential options with all their significant parameters
such as environmental impact, sustainability or social preferences. Perhaps at the end of this process we strongly
acknowledge that we are not dealing with just alternative resources, but we will be dealing with reliable and resilient supply
systems. Resources will probably be as alternative as they were in the past but solutions will be linked to energy, resilience
and sustainability in a new comprehensive and efficient approach.
■ FRANCISCo CubILLo
AbbreviationsA2O Anaerobic–Anoxic–OxicASR Aquifer Storage and RecoveryAWR Alternative Water ResourcesBOD Biological Oxygen DemandCBA Cost-Benefit AnalysisCOD Chemical Oxygen DemandCSP Concentrated Solar PowerCSR Corporate Social Responsibility CSU Colorado Springs UtilitiesCW Constructed WetlandDMA District Metered AreaDPR Direct Potable ReuseED ElectrodialysisEIA Environmental Impact AssessmentESB Engineered Storage BufferFESR Fuel Energy Savings RatioFO Forward OsmosisGL GigalitreGPT Gross Pollutant TrapGRP Goreangab Reclamation PlantGWF Gippsland Water FactoryHKIA Hong Kong International AirportHSFW Horizontal Subsurface Flow WetlandIC Internal CirculationICI Institutional, Residential and IndustrialILI Infrastructure Leakage IndexIMS Integrated Membrane SystemIPR Indirect Potable ReuseIWA International Water AssociationIWRM Integrated Water Resources ManagementKDWS Korean Drinking Water StandardKGWS Korean Gray Water StandardkWh Kilowatt HourLBSE Lithium Bromide-water Simple EffectLCA Life-Cycle AnalysisLID Low-Impact DevelopmentMBR Membrane Bioreactor
MD Membrane DistillationMED Multiple-Effect DistillationMEH Multi-Effect HumidificationMENA Middle East and North AfricaMF Microfiltrationmg/L Milligrams per LitreMm MegametreMNF Minimum Night FlowMSF Multi-Stage FlashMVC Mechanical Vapour-CompressionMWh Megawatt HourNAD Natural Aeration DitchNF NanofiltrationNRW Non-Revenue WaterNWD No Water DayORC Organic Rankine CyclePLP Peak-Load PricingPSDP Perth Seawater Desalination PlantPV PhotovoltaicRO Reverse OsmosisROS Regional Outfall SystemRW RainwaterRWH Rainwater HarvestingSDG Sustainable Development GoalSNU Seoul National UniversitySODIS Solar DisinfectionSW StormwaterTDS Total Dissolved Solids TSS Total Suspended SolidsTWS Triple Water SupplyUASB Upflow Anaerobic Sludge BioreactorUF UltrafiltrationUV UltravioletVBFW Vertical-Baffled Flow WetlandVMD Vacuum Membrane DistillationWUE Water Use EfficiencyWWTP Wastewater Treatment Plant
Contents1 INTRODUCTION 1
1.1 Overview Of Challenges 1
1.1.1 Water Quantity 1
1.1.2 Water Quality 2
1.1.3 Energy and Climate 3
1.2 Drivers Of awr Use 3
1.3 ratiOnale 4
1.4 sCOpe anD ObjeCtives 4
2 RaINwaTeRHaRvesTINgaND
sTORmwaTeRCOlleCTION/maNagemeNT 5
2.1 rainwater harvesting 5
2.1.1 Unlocking the Potential of Rainwater Harvesting 5
2.1.2 Tackling Rainwater Shortage in Dry Seasons 7
2.1.3 Challenges and Considerations in Rwh
Implementation 7
2.1.4 Future of Rainwater Harvesting 8
2.2 stOrmwater COlleCtiOn anD management 9
2.3 infiltratiOn anD green rOOfs 9
3 waTeRReUseaNDDesalINaTION 11
3.1 water reUse 11
3.1.1 Potable Water Reuse 11
3.1.2 Non-Potable Reuse 13
3.1.3 Greywater Reuse 14
3.2 DesalinatiOn anD saline water Use 15
3.2.1 Reverse Osmosis (Ro) 16
3.2.2 Other Non-Thermal Desalination 16
3.2.3 Thermal Desalination 17
3.2.4 Saline Water Use 18
3.2.5 Development on Low-Energy Desalination 18
4 DemaNDmaNagemeNTaNDwaTeRlOss
ReDUCTION 20
4.1 eCOnOmiC inCentives 20
4.2 water-saving teChnOlOgies 22
4.3 water lOss reDUCtiOn 23
4.4 OperatiOnal effiCienCy 27
4.5 eDUCatiOn anD awareness 27
4.6 COmbineD DemanD management sOlUtiOns 28
5 TOwaRDsRelIableaNDsUsTaINable
waTeRsUpplysysTems 30
5.1 COnsiDeratiOns anD examples 30
5.2 inflUenCing faCtOrs in water sUpply systems 33
5.2.1 Environmental Factors 33
5.2.2 Social Factors 33
5.2.3 Economic Factors 33
5.2.4 Political/Institutional Factors 34
6 sHOwCaseOfawRTeCHNOlOgy 35
6.1 hOng KOng internatiOnal airpOrt 35
6.2 perth, aUstralia: rO DesalinatiOn 36
6.3 hybriD COnstrUCteD wetlanDs, China 38
6.4 maDhya praDesh, inDia 39
6.5 tenOriO wastewater treatment plant, mexiCO 40
6.6 gOreangab reClamatiOn plant, winDhOeK,
namibia 41
6.7 gUelph, CanaDa 41
6.8 bOra bOra, frenCh pOlynesia 42
6.9 KOgarah, syDney, aUstralia 43
6.10 star City, seOUl, sOUth KOrea 44
6.11 DeCentraliseD water reUse with
ZerO DisCharge, China 45
6.12 sChOOl DrinKing water sUpply in hanOi,
vietnam 46
7 KNOwleDgeaNDTeCHNOlOgygaps 48
7.1 Data COlleCtiOn anD integratiOn 48
7.2 framewOrK fOr assessing Case-by-Case
sCenariOs On the basis Of envirOnmental impaCt
anD COst-effeCtiveness 48
7.3 mOre effeCtive anD reliable water sOlUtiOns
fOr ariD Climates 48
7.4 high rates Of water lOss 49
7.5 laCK Of pUbliC aCCeptanCe Of reClaimeD
water 49
7.6 safety anD sUstainability in transpOrtatiOn 49
8 ReCOmmeNDaTIONs 50
8.1 awr visibility 50
8.2 teChnOlOgiCal aDvanCement 50
8.3 framewOrK fOr awr assessment 50
8.4 system reCOnfigUratiOn 51
8.5 fit-fOr-pUrpOse treatment anD UtilisatiOn 51
8.6 DynamiC strategies 52
8.7 envirOnmental priOrities 52
9 CONClUsIONs 54
10 RefeReNCes 55
01 IWAALTERNATIVEWATERRESOURCESCLUSTER
1 introductionWateravailabilityisanissueofincreasingglobalconcern.Asusagecontinuestoexceedsustainableratesandgreater
quantitiesofpollutantscomeincontactwithoncepristinewatersources,morepeoplearebecomingconcernedasto
wheretheirwaterwillcomefrom.Anaverageof3.3millionpeoplediefromwater-relatedillnesseseachyearand,in2008,
46%ofpeopleonEarthlivedinhomeswithoutpipedwater(Macedonioet al.,2012).Ifcurrentconsumptiontrends
continue,two-thirdsoftheglobalpopulationwillbelivingwithseverewaterscarcityby2025(Macedonioet al.,2012).
AccordingtotheUnitedNationsWorldWaterDevelopmentReport(UNWater,2015b),demandforwaterisexpectedto
increaseinallsectorsofproductionand,by2030,theworldisprojectedtofacea40%globalwaterdeficitunderthe
business-as-usualscenario.Inadditiontothis,climatechangeisincreasingthefrequencyandintensitybothofdroughtsand
ofstormevents,whilehigherairtemperaturesnecessitategreaterwateruseforcropirrigationandlivestock.Forthese
reasons,alternativewaterresources(AWRs),suchasrainwaterharvest(RWH),waterreuseanddesalination,aswellas
movingtowardsmoreholistic,integratedapproachestowatermanagementarebecomingmorepopularformeetingthe
globalwaterneedsthatmaynotbesatisfiedbyasinglewatersource.
1.1 OVERVIEW OF CHALLENGES
Inthefieldofwaterresourcesmanagement,wearecurrentlyfacingchallengesrelatingbothtothequantityandthequality
ofwatersources.Challengesarediverseintheircausesandeffects,butmustbeconsideredtoensuregreatersustainability
inthewatersector.
1.1.1 WATER QUANTITY
1.1.1.1 Resource Depletion
Notonlyistheglobalpopulationincreasingatanexponentialrate,buteconomicdevelopment,urbanisationand
globalisationhaveresultedintheaveragepersonhavinghigherconsumptionpatternsandweakerconnectionstothe
originoftheirconsumedresources.Meat-heavydietsareontherise,increasingresourceconsumption,andanincreasing
proportionoftheglobalpopulationisconcentratinginmegacities,disproportionatelystrainingresourcesinthoseareas
(ButlerandMemon,2006).Onanevenlargerscale,theamountofwaterneededtoirrigateagriculture(whichcomprises
over70%oftheworld’sfreshwateruse(FoodandAgricultureOrganizationoftheUnitedNations,2013))hashadto
increasetofeedthegrowingpopulation,andascountriesstrivetodeveloptheireconomies,waterneedsinindustrial
sectorshaveincreasedaswell.Thisdemandhastypicallybeenmetbyincreasingtheextractionrateoffreshwaterfrom
surfacewaterbodiesandundergroundaquifers,which–ifitexceedstherateofreplenishment–leadstodepletionof
theresource,andcanpossiblycauselandsubsidenceifgroundwaterisover-extracted.Conventionalwaterresourcesare
nolongersufficienttomeetdemand.AccordingtoNget al.(2013),globalwaterdemandisprojectedtoincreaseatan
averageannualrateof2%,leadingtoademandofcloseto7trillionm3bytheyear2030,asisillustratedinFigure1.1.
Giventhatwaterscarcityisagrowingthreatworldwide,thisrisingdemandislikelytohavedetrimentaleffectsontheglobal
populationanditswaterresourcesifitisnotaddressed.
1.1.1.2 Climate Change and Drought
Climatemodelspredictthatthetrendofincreasingglobalwaterscarcitywillcontinueasclimatechangeimpactsbecome
moresevere.Withthesechanges,precipitationpatternsbecomemoreerratic,evaporationandtranspirationratesrisewith
increasedairtemperaturesandwaterresourcesthereforebecomemorescarceandlessreliable(Olsson,2012).Allover
theworld,particularlyinaridclimates,lakesareshrinkingdramaticallyordisappearingcompletely,affectingbothecosystems
andhumanuse(Liuet al.,2013).Stern(2007)predictsthatjusta2°Cincreaseinaverageglobaltemperaturecouldresult
inbetween1billionand4billionpeople–particularlythoseindevelopingcountries–becomingvictimsofseverewater
scarcity.Someofthewater-relatedimpactsofclimatechangeincludediminishingfreshwatersuppliesduetoshrinking
glaciers,decreasedprecipitationandincreaseddroughtpropensity,higherfrequencyofflooddisastersinsomeareasdue
toseverestormeventsandunreliablesuppliesofbothfoodandwater(Morrisonet al.,2009;Olsson,2012).Theseissues
02 IWAALTERNATIVEWATERRESOURCESCLUSTER
willprobablybecomeexacerbatedashigheratmospherictemperaturesdrivetheneedforincreasedwateruseinagriculture
andlivestockproduction,freshwaterresourcesbecomecontaminatedbecauseofseawaterinfiltrationandpollutant
discharge,andprecipitationpatternsbecomelesspredictable.Ifenergydemandandcarbonemissionsarenotreduced,all
ofthedetrimentaleffectsofclimatechangearelikelytoincreasemorequickly.Therefore,amoreresilientwatersupplyis
needed,asistheproliferationofmoreenergy-neutralpracticeswithinthewatersectortohelpmitigateclimatechange.
1.1.2 WATER QUALITY
1.1.2.1 Risks to Human Health
Thedischargeofwastewaterbackintowaterbodies,dumpingofindustrialchemicalsintothosesamesourcesand
excessiverunoffofstormwateroverpollutedareashaveresultedinthecontaminationofgroundwaterandsurfacewaterthat
wasonceorstillisusedfordrinking.Inmanyareas,contaminantscanbeeffectivelyremovedwithtreatmenttechnology.
However,someregionseitherlackthecapacitytotreattheirwatertopotablestandardsorthecontaminantspresentin
thesupply–suchasheavymetals,pesticidesandevenpharmaceuticalcompounds–cannotberemovedbycurrently
implementedtechnologies.Bangladeshisaprominentexampleofacountrystrugglingtomeetdemandforfreshwater
becauseofsourcecontamination.Arseniccontaminationinaquifershasledtoepidemicratesofcancerandotherdiseases,
withanestimated30millionpeopleexposedtoarsenicinconcentrationsgreaterthan50μg/L.Ontopofthis,muchofthe
country’ssurfacewaterhashighturbidityandsalinity,makingitunfitfordrinkingandnecessitatinganalternativesourceof
clean,reliableandaccessiblepotablewater(Karim,2010a).However,Bangladeshisnottheonlycountrysufferingfrom
theseissues;Pimentelet al.(2004)statethat,indevelopingcountries,90%ofallinfectiousdiseasesarespreadthrough
orrelatedtowater.Pollutioninwatersourcesconstrainstheuseoftheseresources,andpropertreatmenttechnologyor
alternativesourcesofwaterareneededtoovercomethisissue.
1.1.2.2 Ecological Health
Theexcessivewithdrawalofwaterfromrivers,lakesandaquiferscanbeverydisruptivetoaquaticandsurrounding
terrestrialecosystems.McKayandKing(2006)statethatecosystemsarehighlysensitivetothealterationofhydrological
flows,whichoccurswhenwaterisextractedfromriverinesystems.Reducingdepthandstream-wettedareamayalteror
destroythehabitatofcertainorganismsanddecreasebiodiversityintheecosystem.Itcanalsoreducedissolvedoxygen
concentrations,whichcanbedetrimentaltoaquaticorganisms.Inadditiontothis,thedischargeofpoorlytreated
wastewaterorsalinebrineintonaturalbodiesofwatercancauseharmtoaquaticecosystems,especiallywithcontinual
introduction.Compoundingthisissuefurther,thereducedvolumeofavailablewatercausedbyover-extractionconcentrates
thesecontaminantsbecausedispersionislimited.Finally,urbanisationoftenresultsintheremovalofvegetationandriparian
buffers,leadingtofurthercontaminationfromurbanandagriculturalrunoff.
Figure 1.1 Global water demand in 2010 compared with projected global water demand in 2030 (Ng et al., 2013).
03 IWAALTERNATIVEWATERRESOURCESCLUSTER
1.1.3 ENERGY AND CLIMATE
1.1.3.1 Water–Energy Nexus
Waterandenergyareinherentlylinked.Waterisgenerallyneededtoproduceenergy(Mekonnenet al.,2015),and
energyisneededtopump,treatanddistributewater.Thisrelationshipincreasesthecomplexityofbothwaterandenergy
management.Hydraulicfracturingfornaturalgas,oilsandsdevelopmentandthermalenergygenerationareallimportant
sourcesofenergyneededtopowerindustriesaroundtheworld.However,bothoftheseprocessesrequirelargequantities
ofwater,which–ifreturnedtothenaturalenvironment–aredischargedwithsignificantlydiminishedquality.Ontheother
hand,waterscarcityisbeingaddressedthroughtheincreasingimplementationofreuse,desalinationandmoreeffective
treatmentprocesses,whicharegenerallyveryenergyintensive,thustheexistenceofthewater–energynexus.
IntheUnitedStates,thelargestwithdrawalofwaterisforevaporativecoolinginpowergenerationplants,andthelargest
consumptiveuseofwaterisagriculturalirrigation,muchofwhichgoestowardtheproductionoffeedstockforbiofuels.
Increasingly,reclaimedwaterisbeingsubstitutedforpotablewaterintheseendusestoconserveexistingfreshwaterstores,
andthereismuchcurrentresearchfocusingonrecoveringresourcestocreatemoresustainablewaterandenergysupplies.
Cleanwater,aswellasnutrientsandenergy,canberecoveredfromwastewater,andwithtechnologicalinnovationthese
processeswillprobablybecomemoreefficient.However,eveninprocessesinwhichrenewableenergyisused,water
usecanbehigh,andmanywater-efficientprocessesstillrequireagreatdealofenergy.Forthisreason,therelationship
betweenthesetworesourcesisavitalconsiderationinallwaterand/orenergy-relateddecision-makingprocesses
(Schnoor,2011).
1.1.3.2 Non-Sustainable Water-Supply
Manymethodsofacquiring,treatinganddistributingwaterarepoweredbyfossilfuels,whichexistinfinitesupplyandtend
toincreaseinpriceastheybecomescarcer.Excessiveenergyusealsocontributesgreenhousegasestotheatmosphere,
worseningtheimpactsofclimatechange.Therefore,dependenceonthesesourcestomaintainwatersupplysystemsisnot
sustainableinthelongterm(Brown,2013).Utilisingrenewablesourcesofenergysuchaswind,solarorgeothermalcan
helptoalleviatetheseproblems,buttheyoftenrequirelargecapitalexpenditures.Therefore,ifproperinfrastructureisnotin
placeandsufficientfundsarenotavailable,theirimplementationmaynotbefeasible(Gudeet al.,2010).
Anotherunsustainableaspectofpresentwatersupplynetworksistheneedtotransportwaterlongdistancesfromsource
tosuppliertoenduser.Mostmunicipalwatersuppliersarehighlycentralised,andthereforerequireagreatdealofenergy
andpipinginfrastructuretosupplywatertousers.Centralisationcanalsoresultinmorewaterlossasthereismore
potentialforleaksandinefficienciesinthesystem.Adecentralisedwatersupplythattreatsanddistributeswaterlocallyisa
moresustainableoption,andthereforeashifttothiskindofstructuremaybenecessary.
1.2 DRIVERS OF AWR USE
TheOrganisationforEconomicCooperationandDevelopment(OrganisationforEconomicCooperationandDevelopment,
2010)groupsthedriversfortheuseofAWRintofourcategories:socio-economicchanges,technologicalchange,
environmental/externalstressandpoliticalchange.
Socio-economicchangesincludepopulationgrowth,demographicchangesresultingindemandforbetterormore
environmentallyfriendlywaterprovision,expansionofurbanareasandshiftsinactivityfrompublictoprivatesectorsorvice
versa(OrganisationforEconomicCooperationandDevelopment,2010).
TechnologicalchangedrivestheuseofAWRbecauseitoftenmakesnewoptionsavailablewhicharesafer,cleaner
andpossiblycheaperthanexistingstructures.Newtechniquesthatimprovetheresourceefficiencyofwatertreatment/
distribution,simplifyprocesses,enhanceecosystemservices,createmoredurablesystemsandreducepollutionhavethe
tendencytomitigatecostsinwatersectoroperations,bothintheshortandlongterms.However,thisisnotalwaysthecase
(OrganisationforEconomicCooperationandDevelopment,2010).
Environmentalandotherexternalstressesonwaterresourcesarebecomingmorecommonwithhabitualover-extraction,
andclimatechangeislikelytoworsenthissituationinmanyplaces.Manyjurisdictionalareasarerespondingtothis
increasingscarcitywiththeintroductionofwaterreuse,desalination,demandmanagement,etc.Insomecases,itmay
notbeachoice,butanecessitytomeetstheneedsofthepopulation(OrganisationforEconomicCooperationand
Development,2010).
04 IWAALTERNATIVEWATERRESOURCESCLUSTER
Politicalchanges,particularlyregulatorychanges,aremajordriversofAWRimplementation.Includedunderthiscategory
arelandusechanges,waterqualityregulations,effectivenessofgovernanceandrevenuecollection(Organisationfor
EconomicCooperationandDevelopment,2010).
Withinallofthesecategories,costbecomesamainfactoraswell.Lowercostsofrelevanttechnologiesgenerally
increaseuptakeofthesemethods(OrganisationforEconomicCooperationandDevelopment,2010),althoughforward-
thinkingwatermanagersmaymakedecisionsbasedonlong-termcostsaswell.Forexample,ahigher-costtechnologythat
causesminimalenvironmentaldamageislikelytoinducelowermitigationorrestorationcostsinthefuture,andtherefore
maybefavoured.
1.3 RATIONALE
Theexistenceoftheabovechallengesnecessitatesamoresustainableapproachtowatermanagement,onethatdoesnot
relyonasinglesourceofwatertomeetallofanarea’sneeds.Therefore,itisimportanttohaveinformationoftheAWR
optionsavailableandwaysinwhichtheycanbeusedtocreateresiliencewithinalargersystem.ThisCompendiumhas
beencreatedtoreviewalternativeoptionsfocusedonresourcesanddemand,usingevidencefromscientificpapersand
realcasestudiestoassesstheircostsandbenefits.Currentandfuturechallengestowatersuppliesarealsoaddressed,
andrecommendationsaremadeforhowtoeffectivelyandsustainablyintegrateAWRforthecreationofamorereliable
system.
1.4 SCOPE AND OBJECTIVES
WithinthescopeofthisCompendium,allpotentialwaterresources,includingsurfacewaterandgroundwaterwillbe
consideredasAWR.However,owingtoincreasingstrainonexistingsources,morefocuswillbeputonlessconventional
resourcessuchasRWH,reuseanddesalination.Theuseoftheseresourceswillbeconsideredaswaysbothtoaugment
thedrinkingwatersupplyandtocreatemoresecurewatersuppliesforagriculture,industryandotherend-usersofnon-
potablewater.
Withthecompletionofanextensiveliteraturereview,bestpracticeswillbeidentified,alongwiththeiradvantages,
disadvantagesandexamplesofhowtheycanbeintegratedintoasustainablewaterportfolio.Thesolutionsdiscussedwill
rangeintheirapplicabilityfromruraltourbansystemsandfromlow-tohigh-incomecountries.Casestudiesthat
successfullydemonstratethecreationofmorereliablewatersupplieswillbehighlightedtoshowtheviabilityofsuch
projectsandtoinspirenewprojectsofequalintegrity.Thiswillalsohelptoenabletheidentificationofgapsinknowledge
andtechnologythatmustbeaddressed.
Thedocumentaimstocoverawidespatialscale,withexamplesfromeachmajorgeographicareaandarangeof
socio-economicconditions.Thefeasibilityandapplicabilityofdifferentoptionsforenhancingtheresilienceofwatersupplies
varydrasticallybylocation.Eachcountryhasdifferentneedsandresourceavailability,aswellasuniquepoliticalclimates
andeconomiccapabilities.Therefore,attentionwillbedrawntotheseissueswhendiscussingAWR.
ExpertsinrelevanttopicshavecontributedknowledgeaboutthefuturedirectionofAWRuse,andthisinformationis
summarisedattheendoftheCompendium.Finally,asetofrecommendationsaremadeforhowtoeffectivelyand
sustainablyintegrateAWRforthecreationofamorereliablesystem.
TheobjectivesofthisCompendiumincludethefollowing.
• RaisingawarenesswithinthewatersectoroftheapplicabilityofAWRuse.
• Highlightingkeyissuesthatareaffectedordrivenbynon-sustainableresourceuse.
• CompilingandsummarisinginformationonAWRbestpracticestomakeitaccessibletointerestedparties.
• ShowcasingsuccessfulcasestudiestodemonstratedifferentapplicationsofAWR.
• IdentifyingkeytechnologyandknowledgegapsthatexistwithinAWR-relatedsectors.
• Providingrecommendationsfordecision-makersandwaterprofessionalstosuccessfullyimplementAWRsintolarger
managementplans.
• Creatingabasisonwhichprofessionalsandacademicscancollaboratetoshareknowledgeanddevelopsolutions.
05 IWAALTERNATIVEWATERRESOURCESCLUSTER
2 RAINWATER HARVESTING AND STORMWATER COLLECTION/MANAGEMENTRainwaterandstormwaterareseenaspromisingAWRbecauseoftheirlowtreatmentneedsrelativetootherAWR,minimal
environmentalimpactandaddedbenefitsofrunoffandpeakflowreduction.TheapplicationofRWHdatesbacktoaround
2000bc,whereitwasusedinIsrael,partsofAfricaandIndia(Fewkes,2006).Thislonghistoryofusehasresultedin
manycivilisationsbecomingquiteefficientatusingRWHprocesses,evenwithoutthehelpofadvancedtechnology.Itis
alsoasourceofwaterwithminimalpotentialtocreateconflict,astransboundaryandpropertyrightsissuesareunlikely.
However,problemsarisinginrecentyears–suchasthepresenceofemergingcontaminants,rapidpopulationgrowthand
climatechange–haveintroducednewchallengesforRWHthatmustbeaddressedinsystemdesign.
DespitethepotentialofRWH,itspromotionislimited,probablybecauseofmisunderstandingofrainwaterqualityand
unreliablewatersupplyduetoseasonalvariation.However,goodexamplesofRWHexistandscientificinnovationis
narrowingthegapbetweenourcurrentknowledgeandfutureneeds.Whenmorethanonepurposecanbeservedatthe
sametime–suchasfloodmitigation,watersupplyandcontingencyplanning–orwhenrainwaterisusedtosupplement
theexistingwatersupply,theadoptionofRWHispromising.Inallcases,sustainability,technological,economicandsocial
aspectsshouldbeconsidered.
2.1 RAINWATER HARVESTING
2.1.1 UNLOCKING THE POTENTIAL OF RAINWATER HARVESTING
Forthepurposesofthisreport,“rainwater”willrefertoprecipitationthatiscollectedbeforeithitsthegroundandbecomes
runoff.Thisisanimportantdistinctiontomakebecause“stormwater”,whichhasalreadybecomerunoff,willgenerallyhave
differentcollectionsystems,contaminants,treatmentmethodsandenduses.
Thereisalotofmisunderstandingaboutthequalityandquantityofrainwater.Evaporatedwaterfromthelandforms
cloudsandeventuallybecomesrainfall,thequalityofwhichissimilartodistilledwater.Whenitfalls,itmaycontainsome
quantityofairpollutantsandparticulatematter,andintheuseofrooftopRWHsystems,somecontaminantsmaybepicked
upfromtheroof,particularlyifitisnotcleanedwell.Furtherchancesofcontaminationarepresentedifrainwaterrunsoff
ontostreetsanddrivewaysintostreamsandlocalcatchments;thelongerthedistance(mileage)thatrainwaterhastotravel,
thegreaterthechanceofcontamination.Inthewatercycle,rooftop-harvestedrainwaterhastheshortestmileage,and
thereforehasthelowestchanceofacquiringdissolvedandparticulatematter,asshowninFigure2.1.
Figure 2.1 Mileage of rainwater and total dissolved solids (TDS) (provided by Mooyoung Han).
06 IWAALTERNATIVEWATERRESOURCESCLUSTER
RWHcollectsrainwaterfromrooftopsinastoragetank,butmostrainwaterstoragetanksinoperationhaveproblemsto
dowithwaterquality.Thewaterisoftenturbid,containingsuspendedsolidsoreventinyinsectsthatareeasilyobservable
tothenakedeye.Sometimes,thisisaresultofpoordesign,whichcreatesanobstacletoharvestingrainwaterforhuman
consumption.
CurrentprogressinscienceandtechnologyhascreatednewopportunitiesforRWHtobecomeasafesourceofpotable
water.Rainwaterisofhighqualitywhencollectedproperly,andpoor-qualityrainwaterisnotnecessarilyaresultofthewater
itself,butofinadequatesystemdesign,poormaintenanceofequipment(Dobrowskyet al.,2014)orincorrectsampling
methodsfromrainwatertanks.
Ingeneral,theonlycontaminantsinrainwatertanksareparticlesandmicroorganismsfromtheatmosphere(Kaushiket al.,2012),birddroppingsortheroofcatchment(Ahmed et al.,2012).Therefore,itrequiresminimaltreatmentbeforeusingitas
drinkingwater.Manystudieshaveevenreportedthatrainwatercanbeagoodqualitydrinkingwatersourcewithoutany
othertreatmentaslongasthecatchmentandtankaremanagedwell(Coombeset al.,2006;Leeet al.,2012).
Thereareseveralparticleremovalstrategiesusedwhencollectingrainwaterthatmaintainitsqualityinholdingtanks.
SpecificexamplesaredepictedinFigure2.2andareasfollows.
1. Biofilm:biofilminsidethetankmaximisesmicrobialactivitiesforself-purification(Kimet al.,2012;KimandHan,
2013,2014).
2. Calminlet:toavoidre-suspensionofsludge,inflowingenergyisdivertedupwardsbyusingatwo-elbow-typepipe,
allowingthesedimenttoremainundisturbed.
3. Inletbarrieranddrainpipe:sedimentiskeptinthefirstpartofthetank,andfromtimetotimeitisdrainedawayby
openingavalve.
4. Floatingsuction:flowerpollencansometimesenterthetankandfloatonthewatersurface.Bymakingthepipeinlet
10cmbelowthewaterlevel,onlycleanwateriscollected.
5. Siphonicdischarge:whenthewaterexceedsacertainlevel,anyscumfloatingatthesurfaceissiphonedoff.
Figure 2.2 Technical innovation in particle removal (provided by Mooyoung Han).
Finally,averyusefulmethodofremovingpossiblepathogensfromrainwaterissolardisinfection(SODIS).Thisinvolves
exposingrainwaterin2-Lpolyethyleneterephthalatebottlesinasolarcollectortosunlightforabout4–8hours.Complete
disinfectioncanusuallybeachieved,evenunderweakweatherconditions,byaddinginexpensivefoodpreservativessuchas
lemonandvinegar(AminandHan,2009,2011).
07 IWAALTERNATIVEWATERRESOURCESCLUSTER
2.1.2 TACKLING RAINWATER SHORTAGE IN DRY SEASONS
Oneofthebarrierstousingrainwatertoitsfullpotentialisirregularrainfalldistributionoveracalendaryear.Rainwaterisnot
consideredareliablewatersourcebecauseoftheshortageofprecipitationduringthedryseason.Addingtothisproblem,
inmanyruralareas,localrainfalldata–whichareanessentialinputfordeterminingefficientsystemdesign–arenot
available.
Tocopewithwatershortageduringdryperiods,systemscanbecarefullydesignedthroughsimulationmodelling(Mun
andHan,2012).Optimumtankvolumecanbecalculatedwithcatchmentareamappingandtheinputofrainfallandwater
consumptiondata.Strategiestorestrictwaterconsumptionbasedontheremainingwaterinthetankcanthenreducethe
numberofnowaterdays(NWDs)thatoccur(Mwamilaet al.,2015).Anotherwaytoreducewatershortageistodevelopa
site-specificwatersupplysystemwithdualsources:forexample,rainwaterfordrinkingpurposesandgroundwaterforother
domesticpurposesatsitescontaminatedbyarsenic(NguyenandHan,2014).
2.1.3 CHALLENGES AND CONSIDERATIONS IN RWH IMPLEMENTATION
RWHhaslongbeenapopularpracticeatsmalltomediumscales,particularlyinruralandperi-urbanareas.Adoptionrates
forRWHpracticesarenowrisinginurbanareas,andthescaleofthesesolutionsisincreasing.AccordingtoBelmeziti
et al.(2014),15%oftheinhabitantsofFranceareconnectedtoaRWHsystem.Theyinvestigatedthequantityofpotable
waterthatcanbesavedbyapplyingRWHtoalargeurbanarea,inthiscasetheParisagglomeration.Usinggeographic
informationsystem(GIS)-derivedestimationsoftotalrooftoparea,annualprecipitationandtotalwaterdemand,they
concludedthatabout81millionm3peryear–11%ofthearea’spotablewaterdemand–canbereplacedbyrainwaterfor
non-potableuses.
Biswaset al.(2009)conductedasimilarstudyinDwarka,andidentifiedaveragepotentialwatersavingsof16.8%
throughRWH.Themosteffectiveareasinwhichtoharvestanduserainwaterarethosethataredenselypopulatedbecause
thismaximisestheratioofinhabitantstorooftoparea,allowingwatertobeusedmorefullyifcollectionsystemsareefficient
(Chananet al.,2010).However,thesefindingsdonotspeaktotheeconomicfeasibilityoffullimplementation;incentives
oftenstillneedtobeinplacetoencourageinstallationofRWHsystems.
Historically,RWHhasbeenmostcommonlyimplementedinaridandsemi-aridregionsbecauseofthelackoffreshwater
ingroundandsurfacewaterreserves,butclimatechangeandpopulationgrowthhaveresultedinthedepletionofwater
resourcesinmanyhumidregionsthatwereformerlyperceivedaswaterrich.ThishasnecessitatedtheuseofRWH
systemsinareassuchastheUnitedStatesandWesternEurope,andtheadditionalbenefitsofrunoffandpeakflow
reductionmakethesesetupsmoreattractivetobusinessesandmunicipalities.RWHalsocreatesopportunitiesfor
decentralisation,asitcanbeusedclosetothesource,reducingtheneedforlarge-scaletreatmentanddistributionsystems
(DeBusket al.,2013).
DeBusket al.(2013)statedthatautomatedRWHsystemsthatwithdrawwateratregularintervalsforspecificenduses
andarelinkedtoabackupwatersupplyaresuperior,astheypreventsystemoverflow,decreasepotablewaterdemandand
reduceoreliminatethelabourneededintheiroperation.Inadditiontothis,itisrecommendedtohaveanalarmorwarning
lightthatalertsuserswhenasystemmalfunctions,waterlevelsareloworpotablewaterisbeingusedinplaceofrainwater.
Inareasthatdonotsufferfromseverewatershortages,thereissometimesalackofincentivetoimplementRWH
becausethecostofimplementationintheseregionsmayexceedpotentialwatersavings–aproblemthatisexacerbatedby
subsidisationofwatersupplies.RWHsystemsalsohavelimitedefficacyifthecollectedwaterisnotused.Ifsystemsare
keptatcapacityandnotsubjecttoregularwithdrawals,overfloweventswillbepronetooccurringandthesystemwillyield
fewerbenefits(DeBusket al.,2013).
TheresponsibilityofhomeownerstocleanandmaintaintheirRWHsystemsisessential.Inmanypartsoftheworld,itis
commonforhousestohaverooftopRWHsystems,butnotalluserstakenecessarysafetymeasures.Thismostlybecomes
anissuewhenthesystemsinquestioncollectwaterforpotableuses.AstudybyStumpet al.(2012)assessedthe
demographicsandpracticesofhouseholdRWHsystemusersintheUnitedStatesandfoundthattestingofwaterqualityin
thetankswasinfrequent.Infact,theresultsofthestudyshowedthat64%ofparticipantsnevertestedforcontaminantsin
theirrainwatertanks.Althoughthesesetupsusuallydohavetreatmentsystemssuitedtotheexpectedenduse,certain
contaminantsmaypersist,includinglead,whichcanharmyoungchildrenandfoetuses,eveninverysmallquantities.Inthe
studybyStumpet al.,leadwaspresentinsomeofthecollectedsamples,buttheuseofafirst-flushdevicedecreased
concentrationssignificantly,suggestingthatatmosphericdepositionisoccurring.
08 IWAALTERNATIVEWATERRESOURCESCLUSTER
2.1.4 FUTURE OF RAINWATER HARVESTING
2.1.4.1 RWH as a tool to increase the resilience of urban water systems
DecentralisedRWHhashighpotentialinincreasingtheresilienceofurbanwatersystems.Itcanbeusedasabackup
systemwhenthewatersupplyhastemporarilystoppedowingtoasuddenpowerfailure,pipebreakdownornatural
disaster.RWHcanalsomitigatefloodingwithoutincreasingtheexistingsewercapacity,andlocallystoredrainwatercanbe
suppliedforfirefightingtoextinguishfiresintheirearlystages.Reducingpotablewaterconsumptionfromthemainwater
supplybysubstitutingrainwaterfornon-potableusescanalsoreducetheenergyrequiredtotreatanddistributewater,
therebyreducingthecarbonfootprintofthewholenetwork.Furthermore,whenrainwaterisusedtosupplycleanwaterin
developingcountries,itcontributestotheUnitedNations’SustainableDevelopmentGoal(SDG)6,ensuringavailabilityand
sustainablemanagementofwaterandsanitationforall.
2.1.4.2 Multi-purpose RWH and management
AlthoughthereisgrowingglobalawarenessofthebenefitsofRWHthroughsuccessfulRWHprojects,moreeffortputinto
raisingpublicawarenessisneededintheformofmoretangibleincentivestopromotetheinstallationofRWHsystems.
ThemainreasonfortheslowpromotionofRWHistheeconomicfeasibility;thecostoftapwaterisoftentoolowto
justifytheinitialsetupcostsofmostRWHsystems.Thisistrueinmostdevelopedcountrieswherewatersupplysystems
aregenerallyveryestablishedandcomprehensive.However,bytakingintoaccountotherbenefitssuchasfloodmitigation
andcontingencyplanning,multi-purposeRWHsystemscanbeseenasmoreeconomicallyfeasible.ThecaseoftheStar
Citymulti-purposeRWHsystemisanexample,andwillbediscussedingreaterdetailinsection6.10.
Providingeconomicincentivessuchassubsidies,taxexemptionsorequivalentsmayhelptoencourageRWHasa
practice.Publicawarenesscanbeincreased,especiallyamongchildren,byofferingenvironmentaleducationinschools,and
includinginformationonwaterconservation,harvestingandreuse.
2.1.4.3 Rainwater management using IT
SeoulCityannouncedanewregulationtoenforcetheinstallationofRWHsystemsinDecember2004,aschematicof
whichcanbeseeninFigure2.3.Themainpurposeistomitigateurbanflooding,andthesecondarypurposeistoconserve
water.Asaresult,itaimstoensurethesafetyofthecityandimprovethewellbeingofcitizens.Aspartoftheprogramme,
thecityaskscitizenstovoluntarilycooperatebyfillingandemptyingrainwatertanksaccordingtodirectionsfromthe
disasterpreventionagency.
Figure 2.3 Monitoring of a multi-tank system for urban flood prevention and water conservation using IT (provided by Mooyoung Han).
09 IWAALTERNATIVEWATERRESOURCESCLUSTER
Aspecialfeatureofthenewsystemistoprovideanetworkforthemonitoringofwaterlevelsinallwatertanksbythe
centraldisasterpreventionagency.Dependingontheexpectedrainfall,theagencymayissueanordertobuildingownersto
emptytheirrainwatertanksfullyorpartly.Anincentiveprogrammeisinplaceforthosewhofollowthegovernment’s
instructionsandthereissomepunishmentforthosewhodonot.Afterastormevent,thestoredwatercanbeusedfor
firefightingand/ormiscellaneouspurposessuchastoiletflushingandgardening.
2.2 STORMWATER COLLECTION AND MANAGEMENT
Stormwaterrunoffcanalsobecollectedforuse,buttreatmentmethodsgenerallydifferfromthoseusedinrooftop-
harvestedrainwater.Constructedwetlands(CWs)–consistingofvegetation,supportingsubstrateandlivingorganisms
–areafrequentlyusedsystembothtotreatandtostorestormwater.Macrophytesfacilitatethesedimentationofsolidsand
removecertainpollutantsfromthewater;watercolumnstransportpollutantstoactivebiologicalzonesandprovideideal
environmentsinwhichbiochemicaltreatmentprocessescanoccur;andlivingorganismspresentinthewetlandsystemaid
inthetransformationandrecyclingofsomechemicalsubstancesfoundinstormwaterrunoff(Chananet al.,2010).The
addedrecreationalandaestheticvaluemakesconstructedwetlandsidealforurbanareaswheredevelopmenthasledtoa
lossofgreenspace.
Thecollectionofstormwaterrunoffcanbeaneffectivewaytoreduceflooding,streambankerosion,waterpollution,
seweroverflowandotherissueslinkedtoincreasedrunoffgeneration,andmayevenhelptosupplementtheexistingwater
supply.However,someexpertswarnthattheover-extractionofstormwatercanbedetrimentaltostreamhealthand
environmentalflows.Stormwatercollectionregimesshouldbeoptimisedbothtomeeturbanwaterrequirementsandto
restorethehydrologicalprofileoftheareatoasclosetopre-developmentconditionsaspossible(Fletcheret al.,2007).
Figure 2.4 Differences in runoff pathways between water collected by storm drain and water collected by rooftop RWH. Collected stormwater passes over more impermeable surface area than rainwater, and therefore tends to have lower quality (provided by Mooyoung Han).
Oneofthebarrierstocollectingstormwaterrunoff–particularlyinurbanareas–isthehigh-levelcontaminationthatis
generallypresentafterithaspassedoverdirty,impermeablesurfaces(Figure2.4).Forthisreason,stormwaterisgenerally
onlycollectedfornon-potableuses(McArdleet al.,2010).
Bothrainwaterandstormwatercanbeusedforcropirrigation,reducingpotable-qualitywateruseinagriculture.However,
theymustbeusedefficiently,asthecollectionofprecipitationsolelyforirrigationcanbecomeproblematicforseveral
reasons.Thefirstoftheseisthepropensityfortankstooverflowandcreaterunoff-relatedissuesduringnon-growing
seasons.Additionally,inmanycountries,thetimeofyearwhenthemostwaterisneededforirrigationisthetimewhenthe
leastprecipitationisreceived.Therefore,rainwaterforirrigationisbeststoredusinglargetankswithcontrolstoenablethe
slowreleaseofwater,andtohaveabackupusageforthecollectedwatertopreventoverflowduringrainyseasons
(DeBusket al.,2013).
2.3 INFILTRATION AND GREEN ROOFS
Theencouragementofnaturalinfiltrationprocessesisawayinwhichmanyregionschoosetomanagestormwater.Notonly
doesenhancingtheinfiltrativecapacityofanareareducepeakflows,floodriskandrunoff,butthisprocessspeedsupthe
10 IWAALTERNATIVEWATERRESOURCESCLUSTER
rechargeofaquifers,thuscontributingtotheusablefreshwatersupply.Low-impactdevelopment(LID)measuressuchas
permeablepavements,infiltrationgalleries/trenches,bio-retentionsubstratesandgrassswalesarepopularandeffective
meansofincreasinginfiltrationrates.
Liaoet al.(2013)completedastudycomparingtheefficacyoffivedifferent(mostlyinfiltration-based)LIDmethodsin
reducingpeakflowandcontrollingrunoffinurbansub-catchmentswithgreaterthan80%imperviousness.Themethods
includedbio-retention,infiltrationtrenches,permeablepavers,grassswalesandrainbarrels.Theresultsofthestudyare
displayedinFigure2.5,andsuggestthatinfiltrationtrenchesandrainbarrels(i.e.RWH)arethemosteffectivemethodsof
reducingpeakflow,andthesetwo,aswellaspermeablepavers,arethemosteffectivemethodsofreducingtherunoff
coefficientofsub-catchments.
0ZMJ7 ZMJ10 ZMJ57
1000
2000
3000
4000
Pea
k flo
w (
L/S
)
5000
Baseline SimulateBio-RetentionInfiltration TrenchPermeable PavementsRain BarrelsGrass Swale
0.0ZMJ7 ZMJ10 ZMJ57
0.2
0.4
0.6
0.8
Run
off c
oeffi
cien
t
1.0
(b)(a) Baseline SimulateBio-RetentionInfiltration TrenchPermeable PavementsRain BarrelsGrass Swale
Figure 2.5 Effects of five different LID stormwater management techniques on peak flow and runoff coefficient (reprinted from Water Science & Technology 68 (12), 2559–2567 (2013) with permission from the copyright holders, IWA Publishing).
Insomearidorsemi-aridregionsinwhichconventionalRWHsystemsarenotfeasible,butgreaterwateravailabilityis
neededforagriculture,infiltration-basedin situRWHpracticesmaybeused.Thesemethodsinvolvecreatingmicro-
catchmentsinfarmfieldsaswellasmanipulatingvegetationcovertoreduceevaporation,enhanceinfiltrationandincrease
theavailabilityofwaterattherootzone.Anexampleofsuchamethodisthehalf-moonsordemi-lunespicturedinFigure
2.6,whichcapturerainwaterandkeepitonthefield(VohlandandBarry,2009).VohlandandBarry(2009)performeda
studyontheefficacyofin situRWHpracticesinsub-SaharanAfrica,andfoundthatthesesystemshaveanoverallpositive
effectoninfiltration,groundwaterrecharge,biomassproductionandsoilwaterstorage.
Figure 2.6 Man-made demi-lunes created in an agricultural field (Vohland and Barry, 2009).
Greenroofsandurbanfarmingdonotactuallyinfiltraterainwater;however,theycanreducestormwaterrunoff.Theheat
islandproblemcommoninlargecitiescanalsobemitigatedbythecreationofvegetatedgreenroofs,andsomefoodcan
beproducedinadditiontotheformationofanewcommunitygatheringspace.Anewparadigmofconcave-typegreenroofs
aspartofthewater–energy–foodnexusisrecognised,andhasreceivedseveralinternationalawards.
11 IWAALTERNATIVEWATERRESOURCESCLUSTER
3 WATER REUSE AND DESALINATION
3.1 WATER REUSE
Reusingwaterenhancespotentialforconservingexistingfreshwaterresources,manyofwhicharebeingusedbeyond
sustainablelevels.Additionally,waterreuseisamorereliablesourcethanpumpedsurfaceandgroundwaterinsomeareas,
asitislesssensitivetodroughtconditionsandincreaseddemand.Notonlydoesthishelptoensurethequantityofwaterin
lakes,riversandaquifers,butdirectwaterreusepreventsthedeteriorationofwaterqualitysincetheactofdischarging
wastewaterintotheenvironmentcanleadtotheaccumulationofpersistentchemicalsinwater,floraandfauna.
3.1.1 POTABLE WATER REUSE
Recyclingwaterforpotablereuseisbecomingincreasinglypopular.Animportantconsiderationintheseusesisthattherisk
ofillnessfromcontaminationbeextremelylow.Allplantsdesignedtoreusewater–eitherdirectlyorindirectly–should
haveadditionalredundanciesinplacetominimisetheriskofdistributingcontaminantsofconcern(Rietveldet al.,2011).
Indirectpotablereuse(IPR)isthetreatmentofreclaimedwatertodrinkingstandardsafterithasbeendischargedintoa
surfaceorgroundwaterreservoir(Figure3.1).Wastewatermayundergoeitheradvancedorbasictreatmentbeforereaching
theenvironment,butthoroughpurificationmustoccurbeforeitisaddedtothecommunitysupply.TheideabehindIPRis
thatdischargingwaterintotheenvironmentfirstcreatesabuffer,astheprocessesofdispersion,infiltrationandnutrient
uptakebyplantsremovesomeunwantedcontaminants(Leverenzet al.,2011).Itiscommonlyusedaroundtheworld,and
existsbothinaplannedandinanunplanned(de facto)capacity.
Figure 3.1 The pathway of water in IPR, which can use either conventional or advanced wastewater treatment processes (based on Raucher and Tchobanoglous, 2014).
IPRcanproducehigh-qualitydrinkingwaterandisanimportantresourceoptionglobally,butLeverenzet al.(2011)
suggestthatdirectpotablereuse(DPR)maybepreferable,asfewerstepsinthetreatmentprocesscansavecostsand
energy,aswellasreducedischargeofwastestotheenvironment.DPRinvolvestreatingreclaimedwatertodrinking
standardsanddirectlyblendingitwiththepotablewatersupply.InDPR,anengineeredstoragebuffer(ESB)canbeused
inplaceoftheenvironmentalbufferusedinIPR,butisnotmandatory(Figure3.2).Also,IPRmaynotbeanoptioninall
areas,assomecommunitiesdonothavesufficientgroundwaterorsurfacewaterresourcestobehaveasenvironmental
buffers(RaucherandTchobanoglous,2014).
DPRofreclaimedwaterisoftenviewedasapromisingresourceoptionforthefuture.Itreducesthestrainonexisting
surfaceandgroundwatersourcesandeliminatestheneedforaseparatedistributionsystem,whichisnecessarywhen
reclaimingwaterfornon-potableuses.DPRwasfirstimplementedin1969inWindhoek,Namibia(seesection6.6),and
evenatthattimeprovidedasafedrinkingwatersupply(DrewesandKhan,2015).Owingtothecontinualimprovementof
watertreatmenttechnology,itispossibletoreducetheconcentrationsofharmfulcontaminantsinwaterdowntominute
quantitiesthatdonotthreatenhumanhealth.DPRmayalsobelessexpensive,lessenergyintensiveandlesscomplicated
toimplementthanotherwaterresourceoptionsbecauseoftheabilitytoreusewaterlocallyratherthantransportingitlong
distances(Leverenzet al.,2011).
12 IWAALTERNATIVEWATERRESOURCESCLUSTER
Firstly,sourcewatercanvarywidelyitsbiological,chemicalandmineralcomponents,whichiswhyitisimportanttoknow
whatkindofeffluentisbeingdischargedandhowitisregulated.Fullknowledgeofsourcewaterqualityiskeyindeciding
onappropriatetreatmentmethods,andthereforecomprehensivewaterqualitymonitoringshouldbeperformed.Morerobust
systemreliabilitycanbeensuredbycreatingredundancywithmultiplebarriers,enablingtheremovalofawidevarietyof
contaminantsanddesigningresponseplanstoeffectivelymitigatesystemfailures.Aftertreatment,watermustbestoredor
blendedwithotherwatersuppliesbeforedistribution;makingsurethatqualityismaintaineduntilitreachestheconsumer
(DrewesandKhan,2015).
Oneprominentchallengeinwaterreuse–particularlypotablereuse–liesincommunityacceptance;manypeople
areinherentlyaversetodrinkingorusingreclaimedwater.BrownandDavies(2007)conductedastudyassessingthe
communityreceptivitytowaterreuseinaregionofSydney,Australia,andfoundthatpeoples’aversiontowaterreuse
increasedasusesbecamemorepersonal.Table3.1showsthattheacceptanceofrainwaterforalmostallpracticesis
higherthanthatofgreywater,withonly2%acceptingtreatedgreywaterfordrinking.Giventhatthestudywasperformedin
Australia–whereissuesofwaterscarcityareinherentlywellknown–acceptanceofwaterreusepracticesmaybeeven
lowerincountrieswithmoreabundantwatersupplies.Waterprofessionalsaremakingeffortstochangethepublic’s
perceptionofreusedwater.AsLouisvanVuurenoftheNationalInstituteofWaterResearchSouthAfricasaid,“Water
shouldnotbejudgedbyitshistory,butbyitsquality”(Roux,2013).
Figure 3.2 The pathway of water in DPR, which can operate without an ESB (based on Raucher and Tchobanoglous, 2014).
Figure 3.3 Key considerations in the planning and implementation of potable water reuse schemes (reprinted from Journal of Water Reuse and Desalination 5 (1), 1–7 (2015) with permission from the copyright holders, IWA Publishing).
Source WaterCharacteristics
ReliableTreatmentSystems
Storage andBlending
• Source control• Influent monitoring• Flow equalization
• Pilot testing of conventional and advanced processes• Redundancy, robustness, resilience• Performance monitoring/Analytical methods• Emergency facilities
• Introduction into drinking water system• Mineral balance• Disinfection residual• Blending with other supplies
Whetherpotablereuseisdirectorindirect,thereareafewkeyelementsofeverywaterreuseprojectthatmustbe
incorporatedintoitsdesign(Figure3.3;DrewesandKhan,2015).
13 IWAALTERNATIVEWATERRESOURCESCLUSTER
3.1.2 NON-POTABLE REUSE
Non-potablereuseisanimportantapplicationofreclaimedwater,asitcanbesubstitutedforpotablewatertoconservethe
totalsupply.Potentialusesofnon-potablereclaimedwaterincludeagriculturalirrigation,industrialprocesses,street
washing,toiletflushingandlandscaping.Diversifyingnon-potablewaterreusepracticesandimprovingsystemefficiency
maybekeyfactorsinconservingfreshwaterandmeetingdemand(Kalavrouziotiset al.,2015).
3.1.2.1 Agriculture and Landscape Irrigation
Oneoftheprimarynon-potableusesforreclaimedwaterisinagriculture.Reclaimedwatermayevenimproveagricultural
productivityowingtothehighnutrientcontent,andreducingcostsspentonfertiliserwhilestillproducingahighcropyield.
Carret al.(2011)performedacasestudyonthreedifferentresearchsitesinJordan,inwhichrecycledwaterwasusedfor
cropirrigation.Theplant-beneficialnutrientsthatwaterwastestedforwerepotassium,phosphate,sulphateandmagnesium,
andbarleywasthetestcropbeinggrownateachresearchsite(Figure3.4).
Table 3.1 Percentage of study participants who would be open to using either filtered rainwater or treated recycled greywater for several different end uses (reprinted from Water Science & Technology 55 (4), 283–290 (2007) with permission from the copyright holders, IWA Publishing).
Use Filtered rainwater Treated recycled greywater
Drinking 28% 2%Cooking 32% 3%Showering 59% 13%Washingclothes 69% 31%Washingcar 85% 77%Rushingtoilet 85% 87%Wateringgarden 94% 95%
Figure 3.4 Quantity of each plant beneficial nutrient applied to three study fields – Kirbet As Samra (direct), Ramtha (direct) and Deit Alla (indirect) – compared with the average quantity of each nutrient that can be taken up by barley (reprinted from Water Science & Technology 63 (1), 10–15 (2011) with permission from the copyright holders, IWA Publishing).
Kirbet AsSamra
Ramtha Deir Alla Nutrient uptakeof barley
220200180160140120100806040200
Sol
ute
quan
tity
appl
ied
(kg
hect
are-
1)
PotassiumPhosphateSulphateMagnesium
Theauthorsestablishedthatthenutrientsfoundinreclaimedwaterweregenerallysufficienttomeettheneedsoffarmers,
sometimeswithsupplementaryfertiliserneeded.Thisallowedboththeconservationoflimitedfreshwaterresources,as
wellasareductioninfertiliserneeds,allowingfarmerstoreducecosts.Carret al.(2011)statethatwiththecontinual
applicationofreclaimedwatertoagriculturalfields,thepotassiumandphosphatecontentofsoilscanbeenhanced,
leadingtoincreasedproductivity.However,excessivequantitiesofsulphateandmagnesiuminsoilscanreduceagricultural
productivity;thereforethesenutrientsshouldbemonitoredcarefully.Animportantconditionisthatfarmersbewelleducated
aboutthenutrientcontentoftheirirrigationwater,sothattheyknowhowmuch–ifany–fertilisertoapplytocrops,thus
maximisingthebenefitsassociatedwithreusingwaterforirrigation.FindingsbytheWorldBank(2015)suggestedthat
Bolivianfarmershadabroadunderstandingofissuesrelatedtowaterreuseforagriculturalirrigation,andconsequently
wishedtotakepartincommunityeffortstoincreaseagriculturalwaterreuse.
Greywatercanalsobeusedforirrigation,but,likewastewater,itmustundergosometreatmenttoremoveoil,grease,
surfactantsandothercompoundsbeforeitisappliedtocrops.Thisisbecausetheuseofrawgreywaterforirrigationcan
14 IWAALTERNATIVEWATERRESOURCESCLUSTER
drasticallychangethesoilproperties,increasingthehydrophobicityofsoilparticlesandeventuallymakingthesoilunfitfor
agriculturalactivities(Traviset al.,2010).
Reclaimedwateralsohaspotentialusesinlandscapeirrigation,includingparks,cemeteries,golfcoursesandother
non-agriculturalspaces.Thishelpstocurbtheexcessiveuseofpotablewaterfornon-drinkingpurposes,especiallyin
summertime.Thiswateralsogenerallydoesnotneedtoundergodisinfection,thereforereducingenergyrequirements
(Haeringet al.,2009).
3.1.2.2 Industrial Use
Reclaimedwaterhasextensiveusesinindustrybecausewaterqualityguidelinestendtobelessstrictandtheneedfor
potablewaterisreducedoreliminated.Industrialprocessesthatutilisereclaimedwaterincludeevaporativecooling,boiler
feed,washingandmixing(CharteredInstitutionofWaterandEnvironmentalManagement,2012).
AnexampleinwhichthishasbeenimplementedistheGippslandWaterFactory(GWF)inAustralia,whichtreats
domesticwastewateraswellasthatofanearbypulpandpapermill.Thefacilityusesprimarysedimentation,anaerobic
reactors,nutrientremovalbyactivatedsludgeandreverseosmosis(RO).TheGWFcreatesadrought-resistantwatersupply
forindustrialcustomers,andreducesthequantity/increasesthequalityofeffluentdischargedtothenearbyregionaloutfall
system(ROS)(Daiggeret al.,2013).
AnothergoodexampleofindustrialwaterreuseisinTerneuzen,TheNetherlands.TheDOWChemicalmanufacturing
plantusesanintegratedmembranesystem(IMS),consistingofcontinuousmicrofiltrationandtwo-stagesofRO.Asa
result,high-qualityreclaimedwaterisproducedusingsignificantlylessenergyandfewerchemicalsthanwouldbeusedto
desalinateseawatertothesamequality(Rietveldet al.,2011).
Analternativemethodofreusingwaterinamainlyindustrialsettingiscascading,inwhicheffluentfromoneindustrialuser
ispumpeddirectlytoanother;providedtheeffluentqualityofthefirstuserishigherthanthemandatedinfluentqualityof
thesecond.Thorenet al.(2012)performedastudylookingathowwaterreusepotentialcouldbemaximisedinVancouver,
Canada.Usingwaterqualityguidelines,influentandeffluentvolumeandlocationofplants,theyassessedthreedifferent
scenariostoseewhichprovidedthegreatestopportunityforwaterreuseatthelowestcostandenergyexpenditure.Since
theguidelinesinplacerequirethiswatertobeprocessedbeforeitcanbereused,cascadingisnotacost-orenergy-
efficientreuseoptionunlesssatellitewaterreclamationfacilitiesaresituatedinthecentreofindustrialareastotreateffluent
frommultipleusersbeforeitisreallocated.Expandingnetworkstoincludenotonlyindustrialusersbutalsocommercial,
institutionalandmulti-familyresidentialuserswouldfurtherincreasetheefficiencyofthesystemandthequantityofwater
saved(Thorenet al.,2012).However,thistypeofschemetakesadecentralisedapproachtowaterreuse,whichmaynot
beinlinewiththegoalsofalldecision-makers,whomaydisplayreluctanceduetoperceivedrisksandinsteadfavour
centralisation,whichismorecommonindevelopedcountries(Domènech,2011).
3.1.3 GREYWATER REUSE
Bothgreywaterandblackwatercanbereclaimedforfurtheruse.However,sincetheircompositionscanvarydramatically,
thetreatmentprocessesusedmustvaryaswell.Greywatercanbedefinedasanywaterusedinhomesorofficebuildings
excludingthatwhichcontainsfaecalmatter.Themainpollutantsofconcerningreywaterarechemicalcontaminantsfrom
detergents,personalcareproducts,bleachesanddyes.However,microbialcontaminantsarealsoaconcern.While
greywaterhasfewermicroorganismsthandoesblackwater,theconcentrationsofheavymetals,nutrientsandchemicalsare
oftensimilar(Warner,2006).
Onechallengeintreatinggreywateristhehighvarianceincompositionbysource.Greywatercollectedfromakitchen
sinkordishwashermaycontaingreaseandanimalfats,whilewatercollectedfromawashingmachineoftencontainstiny,
non-biodegradablefibresfromclothing.Forthisreason,itisvitaltofiltergreywaterfirsttoremovefibres,celluloseand
grease,andtochangefiltersregularlytopreventclogging.Misinformationtohomeownerscanalsobecomeanissue,as
monitoringandmaintainingon-sitegreywatertreatmentsystemsisoftenleftuptotheowner,whomayormaynothavefull
understandingoftherisksinvolved.Ifasystemmalfunctionsorwaterisusedforincorrectpurposes,theconsequencescan
besevere(Warner,2006).
Anexampleofhowgreywatercanbeintegratedintoamorecomplexsystemistheproposed“GreenVillage”attheDelft
UniversityofTechnology,whichaimstobeanautarkicsystemthroughtheuseofefficienttechnology,greywaterreuseand
RWH(Figure3.5).Builtfrom30recycledshippingcontainersmadeintoofficespaces,dormitories,bathrooms,alunchroom
andalaboratory,theprojectstressesdecentralisationanda“fit-for-purpose”watersupply.DrinkingwaterintheGreen
Villagewillcomefrom100%recycledsources:53%fromrecycledgreywaterand47%fromrainwater.Greywaterwillbe
15 IWAALTERNATIVEWATERRESOURCESCLUSTER
subjecttoatriplebarrierofultrafiltration(UF),UVdisinfectionandozonation,whilerainwaterwillonlybesubjecttoUFand
UV(vanderHoeket al.,2014).
TheGreenVillagewillutiliselowwaterconsumptionappliances–includingvacuumflushtoiletsrequiringabout1Lper
flush–andblackwaterwillbetreatedbyanupflowanaerobicsludgebioreactor(UASB)toproducebiogas,beforebeing
divertedtoaverticalflowconstructedwetlandforsecondarytreatment(vanderHoeket al.,2014).Italsoaimstointegrate
variousmethodsandprinciplesofsustainablewatermanagementintoonedesign.Bylimitingwaterconsumptionthrough
water-savingdevices,treatinggreywaterandrainwaterfordrinkingandotheruses,andproducingenergythroughanaerobic
digestionofwaste,thevillagecanhaveanautarkicwatersupplyandhavearelativelysmallenergyfootprint.VanderHoek
et al.(2014)indicatethattheadditionofwindorsolarenergywouldcreateanautarkicenergysupplyaswell,butthese
aspectshavenotyetbeenincorporatedintotheprojectdesign.
Thereareanincreasingnumberofregulationsmakingacertaindegreeofreusemandatory,particularlyinverywater-
scarcecountries.ThiscanbeseeninIndia,wheretheNationalEnvironmentalPolicystatesthat,asof2006,allnew
buildingsmeetingaspecificsetofcriteriamustincludeawaterrecyclingplanttohelpsupplementthewatersupply.Ontop
ofthis,smallerbuildingsareofferedpropertytaxcreditstoimplementwaterreuse,eventhoughitisnotrequiredbylaw
(Barringer,2014).
3.2 DESALINATION AND SALINE WATER USE
Desalinationisthoughttobeabletoeithergreatlyreduceorcompletelyeliminatewaterscarcityissuesinaridandsemi-arid
regions(ElSalibyet al.,2009).Coastalareasorthoselyingabovesalinegroundwaterreservesoftenhavelimited
freshwateroptions,somakingdesalinationtechnologiesviableandaccessibleintheseregionscouldhelpahighproportion
oftheglobalpopulationtomeettheirwaterneeds.Unfortunately,conventionaldesalinationtechnologiesgenerallystillcarry
highcostsintermsofmoney,energyandenvironmentaldamage,includinggreenhousegasemissions,disruptionofmarine
lifeinconstructionphasesandatplantintakepoints,andthedischargeofchemical-containingsalinebrinethatposesrisks
tomarineecosystems(LattemannandHöpner,2008;BatenandStummeyer,2013).However,theprocessofdesalination
hasbecomemoresustainableandcost-effectiveovertime,andnewandemergingdesalinationmethodsmayhavethe
potentialtoincreasethesustainabilityoftheprocessfurther.Someexpertsevenstatethatitisbecomingpossibleto
desalinateseawaterusinglessthan2.0kWhpercubicmetre,anoveldevelopment(Macharg,2011).
Figure 3.5 Treatment processes to be used in proposed Green Village at the Delft University of Technology (reprinted from Journal of Water Reuse and Desalination 4 (3), pp 154–163 (2014) with permission from the copyright holders, IWA Publishing).
16 IWAALTERNATIVEWATERRESOURCESCLUSTER
3.2.1 REVERSE OSMOSIS (RO)
In2013,thetotalglobaldesalinationcapacitywasdominatedbyRO,whichaccountedfor59%ofcapacity(Nget al.,2013),andthismarketshareiscontinuallygrowing,asistheenergyefficiencyofROtechnology(BatenandStummeyer,
2013).Macedonioet al.(2012)listROtechnologyasthemostpromisingamongmembranetechniquesbecauseitremoves
smallercontaminants–includingsomepharmaceuticalcompounds–andcarriesasmallercarbonfootprintthanmanyother
desalinationtechnologies.Itsdrawbackslieinthelargenumberofjointsandconnectionsintheprocess,theneedfor
additionalpre-treatmentandpost-treatmentstagestoensureadequatesystemperformance,andtheremovalofcertain
mineralsthatmayactuallybedesiredindrinkingwater(Macedonioet al.,2012).Mogheiret al.(2013)suggestthat
improvingthepre-treatmentprocessusingnanofiltration(NF)couldbothimprovewaterrecoveryratesandprolongthelife
ofROmembranesbyreducingscalingandfouling.
ROplantsdischargebrinethatis100%moresalinethantheinfluentconcentration,butisthesametemperatureas
seawater.Thisisincontrasttomultiple-effectdistillation(MED)andmulti-stageflash(MSF)desalinationplants,which
dischargebrineabout15%moresalinethanseawater,but5°Cto10°Cwarmer.Ofthesetwofactors,increased
temperaturehasgreaternegativeimpactsonmarineecosystems.Therefore,despitethehighsalinityofROdischarge,itis
moreenvironmentallysound(Al-KaraghouliandKazmerski,2013).
ROdesalinationisalsodescribedasbeingmorecost-effectivethanthermaldesalinationmethodsbyseveralexperts.
Wittholzet al.(2008)completedacostcomparisonofthemostcommondesalinationmethods,includingMSF,MEDand
RO,andboththecapitalcostsandoperatingcostsoftheROtechnologieswerelower(Figure3.6),whichbodeswellfor
theimplementationofdesalinationinlower-incomecountries.
Figure 3.6 Capital and per unit costs of desalinating water by four different methods (Wittholz et al., 2008).
900.00
800.00
700.00
SWROBWROMSFMED600.00
500.00
Cap
ital C
ost (
US
D·1
06 )
400.00
300.00
200.00
100.00
0.000 200000 400000
Capacity (m3/d)
600000
2.50
2.00
1.50
SWROBWROMSFMED
1.00
0.50
UP
C (
US
D/m
3 )
0.000 200000 400000
Capacity (m3/d)
600000
3.2.2 OTHER NON-THERMAL DESALINATION
AlthoughROiscurrentlythemostwidelyusednon-thermaldesalinationtechnology–aswellasthemostcommercially
viable–manyotherpromisingnon-thermalmethodsexist.
Ghyselbrechtet al.(2013)reportthatelectrodialysis(ED)technologyisbecomingincreasinglypopularowingtoitsability
torecoverionsintheprocess,andaccordingtoTurek(2003),EDcanbeascost-effectiveasRO.However,thecostofED
isdirectlyproportionaltothefeedwatersalinity,soitmaybeinfeasibleforsaltwateraboveacertainconcentration.
Membranedistillation(MD)harnesseslowtemperatureheatsources(renewablesorwasteheat),usingminimalchemical
treatmentandelectricalenergy.SeveraltypesofMDexist,includingdirectcontactmembranedistillation(DCMD),sweeping
gasmembranedistillation(SGMD),airgapmembranedistillation,andfinally,vacuummembranedistillation(VMD),which
tendstohaveahigherfluxrateandlowersusceptibilitytofoulingthanothertypesofMD(RamezanianpourandSivakumar,
2015).
WiththeuseofVMDtechnology,lowtemperaturethermalenergyissuppliedinthefirststageoftheprocess,followedby
severalstagesofevaporationandcondensation(Mendez,2012).VMDhasremovalefficienciesofclose100%forallmajor
parametersofconcern,andremainseffectivewithincreasingfeedwatersalinitymethods(RamezanianpourandSivakumar,
2015).
17 IWAALTERNATIVEWATERRESOURCESCLUSTER
Mendez(2012)statesthatVMD(Figure3.7)isalowmaintenancetechnology,andispronetominimalscalingand
fouling,resultingfromlowtemperatureheatutilisationandhydrophobicmembranes.Thistypeoftechnologymaybe
especiallyimportantinoff-gridlocationswhereconventionalenergyandreliablefreshwatersourcesarenotaccessible.The
applicationoflowtemperatureheatprovidesanopportunitytocouplethetechnologywithwasteheatrejectionstreamsor
renewableenergy,increasingitssustainability(Kemptonet al.,2010).
Anotherformofnon-thermaldesalinationisforwardosmosis(FO),whichusesahighlyconcentratedsolutiontodrawfeed
waterthroughamembrane.Sincethetechnologyusesosmoticpressureinsteadofhydraulicpressure–asisusedinRO
–itrequireslessenergy.MembranesarealsosubjecttolessscalingandfoulingthaninRO,especiallycombinedwith
microfiltration(MF)pre-treatment(Venketeswariet al.,2014).
Thereisevidencethatcouplingdifferentmembraneprocessesmayproduceahigher-qualityendproduct,whilereducing
oreliminatingeffluentbrine(Macedonioet al.,2012).GiventhepromisingaspectsofbothVMDandFOtechnologies,Li
et al. (2014)testedtheefficacyofacombinedFO/VMDsystemonhighlysalineshalegasdrillingflow-backfluid.Usingthe
twomechanismsconsecutively–firstFOwithaKCldrawsolution,thenVMD–waterrecoveryratesof90%efficiency
wereachieved,minimalscalingandfoulingoccurred,andtheresultantdischargehadaqualityresemblingbottledwater,
despitetheinitialpoorqualityofthefeedwater(Liet al.,2014).
3.2.3 THERMAL DESALINATION
Eventhoughthermaltechniquestendtobemoreenergyintensive,withhighercostsandgreaterenvironmentalfootprints
thannon-thermalmethods,theyarestillwidelyused;mainlyinMENAcountries(Macedonioet al.,2012).However,an
increasingnumberofstudiesdemonstratethebenefitsofcogenerationorpolygenerationbycombiningthermaldesalination
withenergygenerationasawaytoreduceenergyuse,costandby-productwaste.AccordingtoGudeet al.(2010),when
aMSFdesalinationplantisconnectedtoapowerplant,thespecificenergyrequiredtoproducefreshwaterissignificantly
lower.ThiswasdemonstratedinKuwait,whereastand-aloneMSFplantused290kJ/kgofenergytoproducefreshwater,
comparedwith160kJ/kgwhenconnectedtoanenergygenerationplant.
Similarly,Maraveret al.(2012)releasedastudyassessingtheviabilityofapolygenerationconfigurationtocreatethree
usefulendproducts:energyfrombiomass,desalinationandcooling.Theproposedsystemhasthreemainsubsystems:an
organicRankinecycle(ORC)engine,aMEDplantandalithiumbromide-watersimpleeffect(LBSE)absorptionchiller.The
systemisidealforisolatedareasinwhichfreshwateravailabilityispoor,butalgae,energycropsorresidualbiomasscanbe
foundeasily,suchasislands.Theauthorsdeemedthisittohaveahighfuelenergysavingsratio(FESR)andpredictedthat
theresultantcostsavingscouldequalinstallationcostsin4–20yearsdependingonthetypeofbiomassused.
Hybriddesalinationmethodscombineboththermalandnon-thermalprocesses,andgenerallyincludeROdesalination
combinedwithMSForMED.ThemostcommonandfeasiblesetupisaRO-MSFplant,whichrequireslowermonetaryand
energyinputsandachieveshigherwaterrecoveryratesthaneachprocessindividually,owingtocouplingofboththermal
andelectricalenergysources.ROcanbeeasilyintegratedintoexistingMSFplants,reducingtheneedforlargecapital
investments(Gudeet al.,2010).AccordingtoKaragiannisandSoldatos(2008),MSFseawaterdesalinationplantscan
Figure 3.7 Aquaver MD desalination unit (Mendez, 2012).
membrane
boiling solution
condensation foil
p1
steam
from external heatsource, i.e. powerplant
p2 p3 p4
concentrate
condenser
distillate
preheatedfeed
18 IWAALTERNATIVEWATERRESOURCESCLUSTER
reducecostsbyupto15%byincorporatingRO,andmanystudieshavefoundthecombinationofthermalandnon-thermal
desalinationmethodstoimproveperformance,costeffectivenessandwaterrecoveryrates.
3.2.4 SALINE WATER USE
Salinewatercanalsobeuseddirectly–usuallyfortoiletflushing–withouttheneedfordesalination.Anexampleofthisis
inuseinHongKong,whereextremefreshwaterscarcityhasledtotheimplementationofadualwatersupply,whichuses
freshwaterforpotableusesandseawaterfortoiletflushing.AccordingtoLeunget al.(2012),thisdualsystemhasbeenin
placesincethe1950s,serves80%ofHongKong’sinhabitantsandhasresultedina20%reductionintotalwaterdemand.
Seawateristreatedwithchlorinetopreventmicrobialgrowthinthepipesystem,distributionpipesarelinedwithcement
mortar,andlong-lastingpolyethylenepipesareusedindoors.Seawater’slackofdiscerniblecolourorodourmakesitwidely
acceptedbyresidentsandtouristsinHongKong.Theoneprominentissuewiththissystemisthatthesalineconcentration
oftheeffluentdrasticallylimitswaterreuseoptions.
SaltwaterisalsobeingusedinQatarforevaporativecoolingandhumidificationingreenhouses.Thisallowsthecrops’
freshwaterrequirementstobeminimised,butsupportshighyieldsandreducestheneedtodesalinatewater,thus
minimisingthecarbonfootprintofthewholeproject(SaharaForestProject,nodate).
3.2.5 DEVELOPMENT ON LOW-ENERGY DESALINATION
Inallformsofdesalination,expenditureonenergy–eitherthermalorelectrical–makesupmorethanhalfofthetotal
operatingbudget,andthemajorityofdesalinationplantsworldwideusefossilfuelstomeettheirneeds(Batenand
Stummeyer,2013).Thisnotonlyleadstohighvolumesofgreenhousegasesbeingemitted,butasfossilfuelsbecome
scarcer,theirincreasingpricesmaymakedesalinationprohibitivelyexpensive.Therefore,thefuturesustainabilityof
desalinationwillbeinfluencedbytheabilitytoincreaseefficiencyintheprocesses,harnessrenewableenergy
sources(BatenandStummeyer,2013)and/orrecoverenergy,whichcanberecapturedfromhigh-pressurepumps
(Macharg,2011).
Renewableenergycanbeacontroversialtopicbecausemanyofthesesources–suchassolarphotovoltaic(PV),
concentratedsolarpower(CSP)andwind–havefluctuatingavailability(vonMedeazza,2004).Also,dependingonthe
technology,renewableenergy-powereddesalinationcanbesignificantlymoreexpensivethanwhereconventionalfuel
sourcesareused(Table3.2).However,thesecoststendtodecreasewithtimeandtechnologicalinnovation,andthe
environmentalbenefitsprovideanincentivetouserenewableenergyregardlessofcost(Gudeet al.,2010).
Table 3.2 Cost comparison (in US dollars) of various desalination methods coupled with either conventional or renewable energy (Gude et al., 2010).
19 IWAALTERNATIVEWATERRESOURCESCLUSTER
Solarstillsmaybeidealforremoteareaswithextremewaterscarcityandlimitedaccesstoelectricity,sincetheyhave
beeninuseformanydecadesandaresimpletoconstruct,althoughthesemaynotbeviableonalargerscale.Solar
multi-effecthumidification(MEH)unitshavegreatercapacityandarestillrelativelysimple.Thelargestoperationusingthis
technologyhasbeenfunctioninginDubai,UAEsince2008,andconsistsofa156m2plant(Al-KaraghouliandKazmerski,
2013).
Therealsoexistseveralviablesystemsthatcouplerenewableenergywithconventionaldesalinationprocesses,suchas
PV-poweredROorEDdesalination.Althoughtheyrequireminimalenergytofunction,theyarerelativelyhigh-costoptions;
mostaccessibletowealthycountries.WindpowercanbecoupledwithROormechanicalvapour-compression(MVC)
technology,andworkswellinremoteareas,butmusteitherhaveacontrolsysteminplacetosmoothoutfluctuationsin
windpatterns,abackupbattery,oradditionalfreshwaterstoragecapacity(Al-KaraghouliandKazmerski,2013).Parket al.(2012)statethatthedevelopmentandapplicationofbetterenergybufferingmethodshasthepotentialtoimprovethe
viabilityofrenewableenergymembranetechnology,andprovidemorereliablewatersuppliesinareaswhereconnectingto
anenergygridisinfeasible.
20 IWAALTERNATIVEWATERRESOURCESCLUSTER
4 DEMAND MANAGEMENT AND WATER LOSS REDUCTIONInconventionalwatermanagementscenarios,theusualresponsetoincreasedwaterdemand–drivenbypopulationand
incomegrowth–hastypicallybeentoincreasegroundwaterand/orsurfacewaterextractionrates.Thishasresultedin
environmentaldegradationandtheoveruseofseveralfreshwaterresources.Controllingdemandsothatlesswaterisused
isamoresustainableoption,andconsequently,manymunicipalitiesandutilitiesusemethodsforachievingthisresult(Table
4.1),suchaseconomicincentives,water-savingtechnologies,metering,awarenesscampaignsandleakreduction.In
general,demandmanagementeitherincentivisestheconservationofwaterresourcesorprovideswaystouselesswater
withoutalteringlifestyle.Measuresthatcontroldemandtendtobelessexpensive,lessenergyintensiveandcarrysmaller
environmentalfootprintsthanAWRtechnologiesthatactuallyaugmentsupply(Grant,2006).Thissectionwillexploreways
inwhichthisispossible.
Table 4.1 Demand management strategies for varying levels of intervention.
Level of intervention Mechanism
Policy Utilitycreditsforimplementingstormwatermanagement,RWH,waterreuseandotherbestpracticesforwatercyclemanagement
Financialincentives,taxexemptionandotheradvantagesofferedonwater-savingappliancesand/oruseofAWR
Certificationsofferedoneco-efficienthomesandbuildings(water/energymanagement)Amendmentofbuildingcodestoincludeconservation/demandmanagementmeasuresAvailabilityoffreewaterefficiency/usediagnosesforhomesandbusinessesImplementationandenforcementofregulationsonwateruseandwithdrawalPublicationoftechnicaldocumentsonbestwater-demandmanagementpractices,made
availabletopublicSupplier Installationofmetersthroughoutentiredistributionnetworkorforselectedusers
AppropriatevolumetricpricingstructuretoensurefairnessandfullcostrecoveryImplementationofefficienttoolsandmethodologiesforleakdetectionandrepairTrainingandeducationforstaffondemandmanagementPubliceducationandawarenesscampaignsApplicationofoperationalefficiencymeasures
Consumer Installationofwater-savingdevicesParticipationinwaterconservation-relatededucationprogrammesandworkshopsIncreasedawarenessofwaterusehabitsRegularmonitoringandsystemassessmenttodetectleaksand/orotherdamagesTimelyrepairofleaksanddamageddevicesandplumbingConservativeandresponsibleoutdoorwateruse,particularlyinsummermonthsSubstitutionoflowornon-waterusingpracticesinplaceofwaterintensivepracticeswhere
possibleUseofAWRwherepossible
4.1 ECONOMIC INCENTIVES
Thereareafewwaysinwhicheconomicincentivescanbeusedtoreducewaterdemandandwhicharegenerallyquite
effective.Theyincluderaisingwaterpricestowardsfullcostpricing,offeringrebatesonwaterbillsforinstallingcertain
watermanagementbestpracticesorofferingdirectrebatesonwater-savingappliances(Biswaset al.,2009).Manyplaces
intheworldstillhavesubsidisedpublicwatersupplies,wherethetruecostofproductionisnotreflectedinthepricepaid
byconsumers.Thisleadstothegradualdilapidationofinfrastructureduetolackofrevenue,andincentiviseswastage
(EuropeanEnvironmentAgency,2013).Ingeneral,higherwaterpricestendtocorrespondtolowerusageratesandvice
versa(Figure4.1).Also,higherpricesdonottendtoinfluencedemandfordrinkingwater,butexcessiveusessuchascar
washingandfillingswimmingpoolsaredecreased(EuropeanEnvironmentAgency,2013).Therefore,re-evaluatingmunicipal
waterpricingstructuresmaybeoneofthefirststepsinmanagingacountry’swaterdemand.
21 IWAALTERNATIVEWATERRESOURCESCLUSTER
0 100 200 300 400 500 600 700
United States of AmericaChinese Taiwan
South KoreaItaly
MexicoJapan
SwedenIran
Hong Kong, ChinaMacao, China
CanadaFinland
SwitzerlandMauri�us
BrazilNorwayFranceCyprusAustria
England & WalesNetherlands
SpainBelgium
DenmarkBulgaria
RomaniaHungary
PolandPortugal
Israel
Specific water consump�on—Drinking water charge*consump�on in litres/capita/day and charge in US$ for 200 m³
Drinking water charge in US$ Specific consump�on in litres/capita/day
Figure 4.1 Comparison of water pricing versus consumption in select countries (International Water Association, 2014).
Animportantconsiderationwhenlookingtocreateamoreequitablepricingschemeisthetypeoffeestructure,ofwhich
manyexist.Householdsmayusebetweenonethirdandonehalflesswaterwhentheyaremeteredandchargedbyvolume
ratherthanbyaflatfee,regardlessoftheactualprices(Brandeset al.,2010;EuropeanEnvironmentAgency,2013).
However,notallvolumetricpricingschemesarecreatedequal,andtheycanleadtodifferentoutcomes.Differenttypesof
variablechargepricingstructurearesummarisedinTable4.2.
Table 4.2 Existing types of volumetric water use fee structure (adapted from Brandes et al., 2010).
Structure Description Comment
Uniformrate Priceperunitisconstantasconsumptionincreases
Targetsallusersequally;simpletocalculatebill
Incliningblockrate Priceincreasesinstepsasconsumptionincreases
Targetshighvolumeusers;requiresmorecomplexcalculatingforbilling
Decliningblockrate Pricedecreasesinstepsasconsumptionincreases
Chargeslowvolumeusersthehighestrate;typicallyusedwhereutilitieswanttoprovidelargeindustrywithalowercostofservice
Excessuserate Priceissignificantlyhigherforanyconsumptionaboveanestablishedthreshold
Canbeusedtotargethighconsumptionduringpeakperiods;moreeffectivewithfrequent(e.g.,bi-monthly)meterreading
Seasonalsurcharges Priceishigherduringpeakperiods(i.e.,summer)
Targetsseasonalpeakdemand;tiedtothehighermarginalcostsofwaterexperiencedduringpeakperiods
Zonalrates Userspayfortheactualcostofsupplyingwatertotheirconnection
Discouragesdifficult-to-serve,spatiallydiffusedconnections
Scarcityrates Priceperunitincreasesasavailablewatersupplydecreases(e.g.,duringdrought)
Sendsstrongpricesignalduringperiodsoflowwateravailability;analternativetooutdoorwateringrestrictions
Lifelineblock Afirstblockofwaterisprovidedatlowornocostbeyondthefixedchargetoensureeveryonehasaminimumamountofwatertomeetbasicwaterneeds
Usedtoaddressequityissuesandensurethatallconsumers’basicwaterneedsaremet
22 IWAALTERNATIVEWATERRESOURCESCLUSTER
Incliningblockstructurestendtodiscourageexcessivewastageandunnecessarywaterusessuchaslawnwateringand
carwashing,butsomearguethatitisunfairtolargefamiliesandgoesagainsttheUNdeclarationofwaterasabasic
humanright,whichiswhylifelineblockstructureshavebeenimplementedinsomeareas(Brandeset al.,2010).However,
atthispoint,therestilldoesnotseemtobeanyonesinglefeestructurethatcansatisfyallconsumers.
Molinos-Senante(2014)proposesadynamicpricingstructurecombininganincliningblockrate(IBR)withadditional
peak-loadpricing(PLP)toconservewaterresourcesintheseasonswhenwaterismostscarce,preventexcessiveusein
thetourismsectorandobtainfullrecoveryofallcostsincurredintheacquisition,treatmentanddistributionofwater
services.Theauthorfeltthat,inadditiontomeetingthestatedgoals,thedualpricingsystemcouldcreatemoreequitable
distributionofcostsamongusersandreduceconsumptioninthetourismsector.
AsimilarincentiveprogrammewasimplementedincentralCalifornia,whereincliningblockpricingstructureswere
appliedtoanirrigationdistricttoreduceconsumption,aswellassalineinterflowtotheSanJoaquinRiver.Crop-specific
pricingtiersweresetonthebasisofpastdataofaverageirrigationdepth,andinformationwasmadereadilyavailableto
farmers.Theprogrammewaseffectiveinreducingirrigationdepth,andingeneral,supportofthepricingstructurewashigh
fromthoseinvolved,suggestingthatfarmersdorespondtoeconomicincentives(Wicheins,2006).
ColoradoSpringsUtilities(CSU)intheUnitedStatestookasimilarapproachbyintroducinganincliningblockrate
structurewithpriceincreaseseveryfiveyears(Figure4.2).Theyalsoofferedrebatesforimplementingconservation
measuresandinvestedinpubliceducation;aidingintheacceptanceoffeeincreases.Includedinthisweremedia
campaigns,communitymeetingsandcallcentrestoanswerquestionsorcomplaints.Withthecombinationofthesefactors,
theprogrammereducedconsumptionbyanaverageof13%,despitepopulationgrowth,andwasgenerallyacceptedbythe
public(WaterResearchFoundation,2015).
Figure 4.2 Colorado Springs Utilities (CSU) inclining block rate structure and fee increases (Water Research Foundation, 2015).
$0.12
$0.10
$0.08
$0.06
$0.04
Cubic Feet per Month
$0.02
2014
2009
2004
1999
$0.00
50 400
750
1,10
01,
450
1,80
02,
150
2,50
02,
850
3,20
03,
550
3,90
04,
250
4,60
04,
950
$ p
er C
ub
ic F
oo
t
4.2 WATER-SAVING TECHNOLOGIES
Water-savingtechnologiescanbeinstalledatmultiplescales,fromhouseholdstolargecommercialandindustrialbuildings,
andincludelowflowtoilets,faucetsandshowerheads,andwater-efficientwashingmachinesanddishwashers,etc.The
ideabehindimplementingthesetechnologiesistoallowuserstoconsumelesswaterwithoutalteringtheirlifestyles.
ThecityofAlbuquerqueintheUnitedStatesimplementedarebateprogrammeforwater-savingappliancesandpractices,
whichhelpedtosignificantlyreducewaterdemandinconjunctionwithsmallpriceincreasesandanawarenesscampaign.
Afterimplementationoftherebateprogramme–between1996and2009–totalwaterdemanddecreasedby16%(Price
et al.,2014).Furthermore,Priceet al.(2014)wereabletodeterminewhichwater-savingdevicehadthebiggestmarginal
impactonconsumption(Table4.3):low-flowtoiletshadthegreatesteffect,followedbyefficientwashingmachinesand
dishwashers.
23 IWAALTERNATIVEWATERRESOURCESCLUSTER
Watersavingmethodsandtechnologiesalsohaveextensiveapplicationsinagriculture,andmayincludewater-saving
irrigation,limitedirrigationanddrylandcultivation.Respectively,thesemethodsuselesswaterwhileachievingthesameor
higheryield;inducedeficitsinthesoil-waterbalanceduringnon-criticalgrowthperiods,andthenirrigateduringessential
stages;andrelyontheefficientcaptureandusageofrainwaterinareasbeyondexistingirrigationnetworks(Denget al.,2006).
Specificmethodsofimprovingwateruseefficiency(WUE)includeselectiveirrigationtorestrictwateringtocriticalstages
ofplantgrowth,croprotation,intercropping,applicationofanimalmanurestoenhancesoilfertility,ormulching,which
decreasessoilevaporationandevapotranspiration,aswellasincreasesingrainyieldandWUE.Theapplicationofchemical
fertilisershasbeenshowntodoublegrainyieldsandthereforeWUE,althoughthiscancausechemicalloadingtowater
bodiesviarunoff(Denget al.,2006;Tischbeinet al.,2013).
ApaperbyDenget al.(2006)examinedthebestwater-savingirrigationmethods,manyofwhichusedharvested
rainwater.Amongtheseareroot-zonedripirrigationandunder-mulchirrigation.Toillustrate,traditionalpracticessuchas
furrowandbordermethodsusewateratarategreaterthan7,000m3perhectare,whereasdripirrigationusesjustover
3,000m3ofwaterperhectare,whileachievingthesameorsimilaryields.
Therealsoexistsavarietyofsmartsensingtechnologiestolimittheuseofwaterforgardeningandirrigationinparticular.
Someofthesetechnologiesincludethefollowing.
• WaterSenseirrigationcontrollers:devicesthatuselocalweatherforecaststodeterminewhenandhowmuchto
waterplants(UnitedStatesEnvironmentalProtectionAgency,2015).
• Soilmoisturesensors:sensorsplacedinthesoiltomeasurethesoilwatercontentandcontroltheirrigationsystem
accordingly(UnitedStatesEnvironmentalProtectionAgency,2015).
• Rainsensorsandshutoffdevices:thesedevicessensewhenitisrainingandshutoffirrigationsystems(United
StatesEnvironmentalProtectionAgency,2015).
4.3 WATER LOSS REDUCTION
Waterlossescanoccurateverystageofthewatercycle;extraction,treatment,distributionandusage,andcomprisereal
andapparentlosses.Theformerincludesleaksandpipebursts,whilethelatterincludesunauthorisedconsumptionand
customermeteringinaccuracies.These,inconjunctionwithauthorised,unbilledconsumptionmakeupnon-revenuewater
(NRW)(TrowandFarley,2006),theglobalannualvolumeofwhichisconservativelyestimatedat50billionm3(Liemberger,
2009).
IfutilitiescanreduceNRWthroughidentificationandappropriatebilling,thecostsavingsarepotentiallyhuge,allowing
utilitiestogreatlyincreasetheirincometocovertheadditionalrepair,replacementandmonitoringcosts.Thisalsoreduces
theneedtoinvestinadditionalinfrastructureortechnologiesforaugmentingthewatersupplybecausetheexistingsupply
willbeabletosatisfymoreofthepresentandfuturedemands(UnitedStatesEnvironmentalProtectionAgency,2013).
Waterlossreductioncanoftenbetheleastexpensiveandmosteffectivemethodofensuringtheadequacyofthewater
supply.Forexample,inthe1980s,UKutilityNorthWestWaterinvestedover200millionpoundsinaprojecttoaugment
Table 4.3 Change in water use due to specific water-saving devices, including low-flow toilets (LFT), water-efficient showerheads (SH), washing machines (WM) and dishwashers (DW), and xeriscaping (XS) (Price et al., 2014).
Change in water use (AWU) due to low-flow device.
Rebate AWU (%)
AWU (Gal/Dav)
Single device AWU (Gal/Dav)
Rebate value ($)
Device lifespan (vrs)
LFT1 −12.86 −37.98 −3798 200 25LFT2 −14.78 −46.87 −8.89(LFT2-LFT1) 400 25LFT3 −14.78 −60.36 −13.49(LFT3-LFT2) 600 25SH/LFT1 −16.26 −46.69 −8.71(SH/LFT1-LFT1) 210 10WM −3.32 −3043 −30.43 100 12DW −4.87 −17.84 −1784 50 10XS(100ft2) −0.84 −3.08 −3.08 75 25
24 IWAALTERNATIVEWATERRESOURCESCLUSTER
supply,onlytoexperienceamere2%increaseinavailablewater.However,bycontrollingtheirleakage–whichaccounted
for35–40%ofthetotalwaterinthenetwork–theywereabletogreatlyincreasethesupplyofavailablewaterwithminimal
spending(Waldron,2001).Thissectionwillexplorethebestpracticesforensuringthatwaterlossiskepttoaminimum.
Leakmanagementhastwomaintypes,activeandpassive(reactive).Passiveleakagemanagementoccursinresponseto
incidentssuchaspipesburstingordropsinpressure.Activemanagementincludesleakagemonitoringandregular
surveyingofthewholedistributionsystem.Theactivemethodispreferable,asitresultsinfewerlosses,butsometimes
resourcesdonotallowforthiskindofstrategy.Whenassessingasystem’swaterlosses,awaterbalanceshouldbe
conductedtoindicatehowmuchwaterisbeinglostandwhereitcomesfrom.Table4.4showsthecomponentsofawater
balance,includingwaterlossesandNRW.However,methodsforcarryingoutawaterbalancevaryindifferentcountries,
makinginternationalcomparisonsdifficult(TrowandFarley,2006).
Table 4.4 Components of a water balance (Trow and Farley, 2006).
Sys
term
inpu
tvo
lum
e
(cor
rect
edfo
rkn
own
erro
rs)
Authorisedconsumption
Billedauthorisedconsumption
Billedmeteredconsumption(includingwaterexported)
Revenuewater
Billedun-meteredconsumption
Unbilledauthorisedconsumption
Unbilledmeteredconsumption Non-RevenueWater(NRW)Unbilledun-meteredconsumption
Waterlosses Apparentlosses UnauthorisedconsumptionCustomermeteringinaccuracies
Reallosses Leakageontransmissionand/ordistributionmainsLeakageandoverflowsatutility’sstoragetanksLeakageonserviceconnectionsuptopointof
customermetering
Tosolvethisproblem,IWAdevelopedaperformanceindicator(PI)calledtheinfrastructureleakageindex(ILI),toallow
internationalcomparisonsofreallosses.TheILIusesseveralparameters,includingtheconditionofthefacility’s
infrastructure,leakage,andpressuremanagementandleakrepairprogrammes(TrowandFarley,2006).TocalculateILI,the
currentannualreallossesaredividedbytheunavoidableannualreallosses(UARL),whichisthesmallestamountofwater
thatcanbelostfromanefficient,well-maintainedsystem.TheadoptionoftheILIbyutilitiesaroundtheworldisanindicator
bothforitsaccuracyandapplicabilityasaninternationalstandard.AnILIvaluelowerthan2meansthatthecurrentreal
lossesarelessthantwicetheunavoidablelosses;systemswithsuchILIvaluesaregenerallyconsideredtobeavery
efficient(Delgado,2008).
Figure 4.3 Four pillars of leakage management (Trow and Farley, 2004).
PressureManagement
Annual Volumeof Losses fromLeakage and
Overflows
Speed andQuality of Repairs
Active LeakageControl
InfrastructureManagement
25 IWAALTERNATIVEWATERRESOURCESCLUSTER
IWAalsodevelopedfourmainpillarsofleakagemanagement(Figure4.3).Thepillarsincludepressuremanagement,
speedandqualityofrepairs,infrastructuremanagementandactiveleakagecontrol,eachofwhichhavediminishingmarginal
returnsinreducingthevolumeoflossesandleakage(TrowandFarley,2004).
Perhapsthemostimportantofthesefourpillarsispressuremanagement,asmorewatercanbequicklysavedthrough
thismethodthananyother.Controllingpressureindistributionsystemscanbeextremelyefficientatreducingleakage,and
dosoatalowcost;mostpressuremanagementprogrammeshavepaybackperiodsoflessthantwoyears.Typesof
pressurecontrolincludeflow-modulatedcontrol,time-controlandfixed-outletcontrol,andthebestmethodtouseis
dependentonthesupplysysteminquestionandthefundsavailable.Astrongexampleoflargescalewaterlossreduction
withpressuremanagementistheKhayelitshainstallationinSouthAfrica,theimplementationofwhichresultedinannual
watersavingsof9millionm3;a40%decreaseinaveragedailyflow(7thWorldWaterForum,2015).
Itshouldbenotedthatdirectcomparisonscannotalwaysbemadebetweenpercentagesofwaterlossreduction.
Consumptionofwatercanvaryenormouslyowingtotheweather,makingapercentageleakagerateappeartodoubleor
halfduringextensiveperiodsofrainordroughts.Watersupplysystemscarryinherentdifferencesinsize,demandand
complexity;twoutilitiesexpressingthesamepercentreductioninlossesmayhavehadvaryinglevelsofsuccess.Therefore,
caremustbetakenwhenusingpercentagesforsuchcomparisons,anditiswisetoalsohaveanalternativefigureto
compare,suchaslitresperpropertyperhour,litresperlengthofwatermains,andideallyshowingtheILIvalue.
Theexistenceofwaterlossescanbeprovedwithacombinationofsmartmetering,districtmeteringandbulkmetering
systems.Integratingthesedataallowsutilitiestoquantifyleakagewithrelativeaccuracyandanalysenightflowratesto
improvewaterlossreductionstrategies.Loureiroet al.(2014)achievedthisbyusingselectdistrictmeteredareas(DMAs)
ascasestudiesandcollectinghourlycustomerdatafrommeters,thenusingalgorithmstodeterminewhichcomponents
wereapparentlosses,assumingthatreallossesstayedfairlyconstant.Theywerealsoabletodetectpipeburstsandillegal
waterusethisway(Figure4.4).Usingthecollecteddatatoimprovetheirunderstanding,theauthorswereabletomake
targetedeffortstoreducelossesbyanaverageof10%inthestudiedDMAs.
Figure 4.4 Flow profiles of a chosen DMA, modelled to detect illegal water use and pipe bursts (reprinted from Water Science & Technology: Water Supply 14 (4), 618–625 (2014) with permission from the copyright holders, IWA Publishing).
8.0(a)
7.0
6.0
5.0
4.0
3.0
Flo
w (
m3 /h
)
2.0
1.0
0.03-Dec 5-Dec 7-Dec
DateTotal inflowNon-revenue waterReported leaks and bursts
Total metered consumptionReal lossesApparent Losses
Total inflowNon-revenue waterReported leaks and bursts
Total metered consumptionReal lossesApparent Losses
Reported pipe burst
9-Dec 11-Dec
9.08.0
(b)
7.06.05.04.03.0F
low
(m
3 /h)
2.01.00.0
5-Jan 7-Jan 9-JanDate
Illegal water use
11-Jan 13-Jan 15-Jan
Apromisingtechnologyformonitoringandreducingreallossesinwaterdistributionsystemsistheimplementationof
automaticmeterreadingforservicepipes,whichautomaticallycollectsconsumptiondataandtransfersittoacentral
database,eliminatingtheneedtomanuallycheckmeters,whichcanbetime-consumingandleadtomorewastage.
automaticmeterreadingmayalsoallowformoreaccuratedetectionofleaksthatmaynototherwisehavebeenfound,as
wellaspreciseestimationsofleakagefromnight-timeflows.Thecommonpracticeofestimatingnight-timeleakagehas
beenthesubjectofcriticism,withsomeexpertsstatingthatitlacksaccuracy.Theprovisionofharddataandaccurate
minimumnightflow(MNF)valuestoutilitiesisinvaluableincalculatinglosses,detectingleaksandcreatinggreater
efficiencyinsystems(Waldron,2007).
InastudybyMunet al.(2008),acomprehensivewaterlossmanagementstrategywasimplementedinKorea,inacity
withhighratesofwaterlossduetopoormanagement,old,dilapidatedpipes,andarevenuewaterratioofonly55%.The
mainmethodsadoptedtoreducewaterlosswerethefollowing:
1. introductionofablockzoningsystem;
2. piperehabilitation/replacement;
3. pressurecontrol.
26 IWAALTERNATIVEWATERRESOURCESCLUSTER
Thezoningsystem–inwhichthewholeserviceareaisdividedinlargeblocks,thenagainintomediumandsmaller
blocks–helpstomakethesystemeasiertomonitorandmaintain.Eachblockismonitoredforpressureaswellaswater
qualityandquantity,andleakscanbemoreeasilyidentifiedandrepaired.Italsoprovidesanadditionalelementofcontrolin
emergencies,asproblemlocationscanbeisolated.Thesecondmethodusedinthemanagementstrategywaspipe
rehabilitationandreplacement.50kmofpipe,aswellasallwatermetersandvalveswerereplacedowingtoleaks,
blockageorcorrosion.
ThethirdandmostcriticalelementoftheKoreancasestudywaspressurecontrol,inwhichvalveswereinstalled
accordingtotherangeofinitialpressuretohavemaximalefficacy.Munet al.(2008)isolatedtheeffectsofpressurecontrol,
andfoundthatthisstepaloneledtoa25%decreaseinwaterproductionanda10%increaseintherevenuewaterratio.
Figure4.5showstheeffectoftheentireprogrammeovera2-yearperiodontherevenuewaterratio,whichincreasedfrom
55%to70%between2004and2006.
Figure 4.5 Production, consumption and revenue water ratio in the study location of Mun et al. (2008) from the beginning of 2004 to the end of 2006 (reprinted from Water Practice & Technology 3 (2), 1–7 (2008) with permission from the copyright holders, IWA Publishing).
1,600,000
1,400,000
1,200,000
1,000,000
800,000
600,000
400,000
200,000
2004
-1 3 5 7 9 11
2005
-1 3 5 7 9 11
2006
-1 3 5 7 9–
Pro
du
ctio
n &
Co
nsu
mti
on
(m
3 /day
) 80productionconsumptionrevenued water ratio 70
60
50
40
30
20
10
0
Rev
enu
ed w
ater
rat
ion
(%
)Itisimportanttoconsidersocio-economicfactorswhencreatingstrategies,aslow-andmiddle-incomecountriesaccount
forabout70%oftotalwaterlossesworldwide.AccordingtoLiemberger(2009),SouthandSoutheastAsiahavesomeof
thehighestratesofwaterlossintheworld.InIndiaespecially,mostwaterutilitiesexperienceintermittentsupply,sometimes
foronly3–5hourseveryfewdays.Evenwiththislackofcontinuoussupply,waterlossratesareextremelyhighowingto
poormaintenanceanddegradedinfrastructure.Therefore,evenifsupplyweretobecomecontinuous,NRWwouldbeso
highthatthetotalsupplywouldnotbeimproved.
Anotherfactoratplayisthetypeofwaterlosstakingplaceandinwhatproportion.Someutilitieshavehighervolumesof
unbilledcommerciallossesduetocorruption,theftorpoormetering,thanphysicallossesduetoleakage,andviceversa.
Waterlossreductionstrategiesshouldincludeinvestmentininfrastructurerepairandmaintenance,aswellasmeter
installationandincentivestoreducetheftandunbilledconsumption.Therealsoexistsalackofdataonwaterlosses,
especiallyindevelopingcountries,andthereforedatacollectionshouldbethefirstcourseofactionindevelopinga
managementstrategy(Liemberger,2009).
Unfortunately,methodsofreducingwaterlossescanbeveryexpensive,sometimesprohibitivelyso.Itisnotuncommon
forgovernmentsandutilitiestoinvestminimallyinageinginfrastructure:ashort-sightedapproachthatleadstogreatercosts
inthefuture.AprominentexampleofthisisMontreal,Canada,whichloses40%ofwaterinthesupplysystemeveryyear
becauseofdilapidatedinfrastructure.Athirdofthecity’swaterpipeshavealreadyreachedtheendoftheirusefullifespan,
andtheothertwo-thirdsarepredictedtoreachthispointwithinthenext20years(FraserInstitute,2010).Despitethepoor
stateofMontreal’swatersystem,thecityhasyettoimplementthestepsnecessarytochangeitbecauseofthe4 billion
Canadian dollar investmentthatwouldberequiredtoupgradeinfrastructure(FraserInstitute,2010).Further
exacerbatingtheissueisthelackofinstalledmetersandtheflatfeepricingstructure,subsequentlycreatingalackof
revenueforwaterutilities.Implementingpricingstructuresthataccuratelyreflectthecostofproductionmaybeastepinthe
rightdirectionintermsofreducingwaterlosses,butwouldprobablybemetwithdisapprovalfromresidentswhohave
grownaccustomedtopayingthecurrentrates.
27 IWAALTERNATIVEWATERRESOURCESCLUSTER
Ingeneral,water-lossreductionstrategiesmust
• betailoredtothespecificlocationofthewatersupplysystem;
• bewellintegratedintosurroundingsystems;
• beforward-thinkingwithawillingnesstoinvestinlong-termsustainability;
• takeintoaccounttheeconomic,social,politicalandenvironmentalfactorsofanarea.
Bytakingthesesteps,moreholisticandeffectivewater-lossreductionstrategiescanbeachieved(SchoutenandHalim,
2010).
4.4 OPERATIONAL EFFICIENCY
Operationalefficiencyreferstotheoutputtoinputratioofwatertreatmentprocesses,andanimportantpillarofwater
managementisthedevelopmentofstrategiesortechnologiesthatwillenhancethisefficiency.Thiscaninclude
implementingtechnologiesthatemitfewerwasteproducts,formingpartnershipstocreateeconomiesofscaleoragreater
rangeofexpertise,andimprovingsupervisorycontrolanddataacquisitionofwatersupplysystems.Onewayofensuring
betteroperationalefficiencyistheuseofpropercleaningandmaintenanceoftreatmentsystems.Toofrequentcleaningcan
resultinunnecessarywastage,whereasinfrequentcleaningresultsinpoorperformanceandclogging.Monitoringeffluent
turbidityorhydraulicheadlossandthencleaningwhennecessaryallowssystemstoperformoptimallywithoutwasting
resourcesonover-cleaning.Airscoursystemsandair/waterbackwashsystemsarebothefficienttechnologiesforcleaning
filtrationsystems(UnitedStatesEnvironmentalProtectionAgency,2013).
Operationalefficiencycanalsobeenhancedthroughimprovedstoragecapacity.Issuesoftenarisebecauseof
discrepanciesinwaterneedsbetweenseasons,forexample,periodsofhighestrainfallalsotendtobeperiodswiththe
leastwaterdemand,andviceversa.Withconventionalabove-groundstoragemethodssuchastanksandreservoirs,
overflow,contaminationanddiminishedqualityovertimearepotentialproblems.Aquiferstorageandrecovery(ASR)–
inwhichtreatedwaterisintroducedtoaquifersforstorageuntillateruse–isawayofovercomingthiswhilemaintaining
thewatertable,reducingtheriskofcontaminationandensuringadequatewatersupplyintimesofhighdemandor
supplyinterruption(Niaziet al.,2014).ASRespeciallyimprovesoperationalefficiencyfordesalinationandwaterreuse
becauseitallowsforsteadyenergyuse,removingtheneedforlargevariationsthatcanresultinwastage(Ghaffouret al.,2013).
4.5 EDUCATION AND AWARENESS
Educationandawarenessofenvironmentalandwaterscarcityissuescanbepowerfultoolsinreducingwaterdemand.
Examplesofthisincludeschool-levelwaterconservationprogrammes,radioandTVmessagesandinformationinmail-outs,
workshopsornewspaperadvertisements.Thisisamechanismthat,evenifitdoesnotcreatepermanentdemandreductions
onitsown,canbeincorporatedfairlyeasilyintoanydemandmanagementstrategywithverylittledownside.
Fieldinget al.(2013)performedanexperimentalstudytotesttheeffectsofvariouseducation-basedinterventionson
householdwaterdemandinAustralia.Theaveragedailywateruseforallgroupsdecreasedduringandimmediatelyafterthe
interventionperiod.Unfortunately,allgroupsreturnedtopre-interventionlevelsofwateruseby12monthsafterthe
interventionsceased,suggestinganeedforadditionalmeasures.Fanet al.(2014)alsostatethatifusersdonothave
accurateperceptionsoftheirownwateruse,educationcampaignsandotherdemandmanagementstrategiesmaybeless
effective,andthereforeawarenesscampaignsthatallowconsumerstorealisetheirownconsumptionpatternsarelikelyto
bemoresuccessful.
Watermeteringisanindirectdemandmanagementtoolthatmayhelptoenhanceawarenessofwateruse.Watermeters
allowtheexistenceofleakstobeproved,andenableutilitiestoimplementperunit,volumetricpricingstructures,which
incentivisemoreconservativewateruse(seesection4.1).Finally,whenaconsumercanseehowmuchwaterisbeingused,
theincreasedawarenessmaypromotemoresustainableconsumptionpatterns(Bealet al.,2011).Studieshaveshownthat
theinstallationofwatermetersleadstowatersavingsofbetween10and30%,andcanbeashighas50%(Biswaset al.,2009).
28 IWAALTERNATIVEWATERRESOURCESCLUSTER
4.6 COMBINED DEMAND MANAGEMENT SOLUTIONS
Somedemandmanagementmechanismsarestrongerthanothers,andadditionalbenefitscangenerallybeaccruedby
combiningseveralstrategiesinonejurisdictionalarea.Table4.5comparesthedemandmanagementstrategiesofvarious
locations,andtheaveragereductionsinwaterdemandthatwereachieved.
Table 4.5 Comparison of different demand management case studies and their associated water use reduction.
Location Pricing Metering Water saving
devices/methods
Water loss reduction
Education & awareness
Legislation Average Reduction
Study
Canada ● ● 43% Brandeset al.(2010)
NewMexico,USA
● 16% Priceet al.(2014)
China ● 56% Denget al.(2006)
SouthAfrica ● ● ● ● ~42% Buckle(2004)India ● ● ● 8-20% Biswaset al.
(2009)Australia ● 6-15% Fieldinget al.
(2013)Colorado,
USA● ● ● ● 13% WaterResearch
Foundation(2015)
Portugal ● ● 10% Loureiroet al.(2014)
SouthKorea ● 25% Munet al.(2008)
Guelph,Canada
● ● ● 18% CityofGuelph(2013)
Windhoek,Namibia
● ● ● ● 35% SharmaandVairavamoorthy(2009)
Someotherexamplesofcountrieswhichmanagedemandeffectivelyarethefollowing.
• Singapore,whoseNRWexpressedaspercentageofsysteminputvolumeislessthan10%.Theyuseeconomic
incentives,comprehensiveeducationprogrammesandconservationmeasurestoreducedemandforwaterresources
(SharmaandVairavamoorthy,2009).
• TheUK,whoseleakreductionprogrammesmanagedtoreduceleakagebycloseto30%between1994and2009.
Also,promotionofwater-savinghouseholddevices,alongwithawarenesscampaigns,haskeptpercapita
consumptionrelativelylow(SharmaandVairavamoorthy,2009).
• SouthAfrica,whoseactiveleakagecontrolprogrammeandretrofittingofpublicanddomesticbuildingshasreduced
waterdemand(SharmaandVairavamoorthy,2009).
• France,wheretheprovinceofBrittanyusededucationcampaigns,letterstoresidents,leakagemonitoringand
water-savingdevicestocontrolwaterdemandbothinpublicandinprivatesystems,achievingwatersavingsof
between14and79%,dependingontheuser(SharmaandVairavamoorthy,2009).
Unfortunately,developingcountriesaregenerallylesswellsuitedtobenefitfromdemandmanagementstrategiesbecauseof
lowerincome,dilapidatedinfrastructure,reducedelasticityofdemandforwaterandlowerinstitutionalcapacity.
Animportantconceptintheintegrationofdemandmanagementsolutionsisthatofdifferentordersofscarcity.Thefirstof
theseisphysicalscarcity,inwhichthereisphysicallynotenoughfreshwatertomeettheneedsofthepopulation.Second-
29 IWAALTERNATIVEWATERRESOURCESCLUSTER
orderscarcityreferstoscenariosinwhichthewatersupplyisnotphysicallyscarce,butcontamination,poormanagementor
inefficientusemakesasignificantquantityoftheresourceunusable;thisistechnologicalorinstitutionalscarcity.Third-order
scarcityreferstothesocial,politicalandculturaldimensionsofwaterscarcity;theperceivedabundanceofwaterleadingto
overuseorhabitualhigh-consumptionlifestyles.Justasthesethreeordersofscarcityaredifferent,sotooaretheirpotential
policyresponses,listedinTable4.6(WolfeandBrooks,2003).
Table 4.6 Overview of the three orders of scarcity, the dominant disciplines applicable to them and their response options (adapted from Wolfe and Brooks, 2003).
Order of scarcity Dominant discipline Responses
First Engineering Supply-sideprojects(dams,pipelines,canals,wells,desalination)
Second Economics Demand-sidemanagement;waterasaneconomicgood;technicalfixes
Third Socialscienceswithinbiophysicallimitations
Newoptionsandreallocation,technologicalchange,‘water-soft’paths
Thegoalofthird-orderscarcityresponsesistoshiftsocietalnormsawayfromhighconsumptionlifestylesandmake
conservationpracticesstandard.Thisreallocationofresourcesinfavourofconservationiscalleda‘watersoftpath’,the
implementationofwhichisbecomingmorepopularinresourcesmanagement.Thesepracticescanbedifficulttoimplement,
butnaturallycurbdemandandincreasethesustainabilityofwateruse,andshouldbeintegratedwithpoliciesaddressing
first-orsecond-orderscarcitywhereneeded(WolfeandBrooks,2003).
30 IWAALTERNATIVEWATERRESOURCESCLUSTER
5 TOWARDS RELIABLE AND SUSTAINABLE WATER SUPPLY SYSTEMSThereisagrowingneedforreliableandresilientwatersuppliesthatusethehighestefficiencyuseofalternativeand
conventionalwatersourcesinconjunctionwithminimisedenergyuse.
Infinancialsectors,a“portfolio”managementconceptisused,whichaimstomitigateriskbyspreadingitbetween
severaldifferentresourceoptions(PaydarandQureshi,2012).Inthecaseofwatermanagement,asimilarconceptofthe
“portfolio”approachcouldbeconsidered,whichmeansutilisingwaterfromavarietyofdifferentsources–someofwhich
shouldbehydrologicallyindependent–tocreateamorerobustsupply.Acomprehensiveunderstandingofboth
hydrologicalandeconomicconceptsiscrucialwhenusingthiskindofapproach.Portfolio-basedwatermanagement
projectsshouldaimnotonlytoeffectivelymanagethewatersupplybutalsotoincreaseenvironmentalsustainability,use
energyefficientlyandyieldsocialbenefits.
Theportfolioapproachbearssomeresemblancetointegratedwaterresourcesmanagement(IWRM),butthetwoarenot
oneandthesame.IWRMcoversabroaderformofwatermanagementthat“promotesthecoordinateddevelopmentand
managementofwater,landandrelatedresourcestomaximiseeconomicandsocialwelfareinanequitablemannerwithout
compromisingthesustainabilityofvitalecosystems”(GlobalWaterPartnership,2012).Whilethismayincludeusinga
portfolioapproach,itisnotmandatory,asIWRMplansmayfocusonasinglewatersourcewithinthescopeofitsmain
principles.
RegardlessofwhetherornotapproachestowatermanagementarecategorisedunderportfoliomanagementorIWRM,
theyshouldaimtocreatemorereliableandsustainablewatersupplysystems.
5.1 CONSIDERATIONS AND EXAMPLES
EachpotentialAWRcarrieschallenges,andwiththosechallenges,possiblesolutions(Figure5.1).Itshouldbenotedthat
lakes,rivers,reservoirsandgroundwatercanalsobetreatedas“alternative”waterresources,butFigure5.1aimsto
summarisetheresourceoptionsdiscussedinChapters2–4.Watertrading/transfersmayalsobenecessaryinsomeparts
oftheworld,particularlyinthecaseofdroughts,disastersorotherextremeevents,butthesearenotincludedinthescope
ofthispaper.TherearemanymorepotentialproblemsandsolutionsinherentinAWRthanaredepictedinFigure5.1,but,
tosimplifythevisualrepresentation,onlymoreprevalentconcernswereincluded.
Thepresenceofthesechallengesinherentineachwatersupplyoptionmakesdiversifyingwatersuppliesevenmore
crucial.Combiningmultipleoptionscreatesredundanciesinthesystem,reducingtheriskofhavinginsufficientfreshwater
suppliesorissuesofpublichealth.
Themonetaryandenergycostsofallpossibilitiesshouldalsobeconsidered,toassessthefeasibilityofcertainoptions
againsttheavailablefundsandenergysources;thenavariedportfoliocanbebuiltoutoftheseoptions.Table5.1provides
ageneralisedcomparisonoftheaveragemonetaryandenergycostsofseveralwaterresourceoptionsusedworldwide.
Figure5.2depictsavisualrepresentationofthesameinformation.
ChinaandotherAsiancountrieshavebegunusingAWRinanintegratedapproach,andhaveseenimprovementsin
socio-economicconditions,environmentalhealthandwaterscarcityfactors.Wanget al.(2014)modelledthreepotential
futurescenariosfortheTongzhoudistrictinChina–business-as-usual,planning-orientedandsustainabledevelopment–to
predicttheireffectsonlocalindustry,GDPandwaterscarcity.Thefirsttwoscenariosusedonlygroundwaterandsurface
watertomeetdemand,whereasthesustainabledevelopmentscenariomethalfofitsdemandwithreclaimedwaterand
incorporatedwatertransfersaswell.Underthebusiness-as-usualscenario,thetotalwaterdemandin2020waspredicted
tobeabout366millionm3,whileinthesustainabledevelopmentscenarioitwas375millionm3.However,eventhoughthis
scenario’stotalwaterdemandwasslightlyhigher,itmetalmosthalfofitsdemandwithreclaimedwater,andexperienced
thegreatestGDPincreasesduetoastrengthenedtertiarysector,andmoreefficientwateruseintheprimarysector.
Californiaisaprominentexampleofawaterportfoliothatiscurrentlybeingexpandedtorespondtoscarcity.In2015,
Californiaimplementedmandatoryusagecutsof25%below2013levelstoutilitiesaftervoluntaryreductiontargetsin2014
werenotmet(BluefieldResearch,2015).Asoftheendof2014,45regionsinthestatehadimplementedcomprehensive
integratedwaterresourcesmanagement(IWRM)plans,withmoreplanned(CaliforniaDepartmentofWaterResources,
2015).InJanuary2015,overUS$850millionwasallocatedtoplannedandcurrentwaterreuseanddesalinationprojectsto
shiftdemandawayfromsurfaceandgroundwatersupplies.Whilereuseanddesalinationhavebeenslowtotakeholdin
Californiabecauseofhighcostsandcommunityopposition,droughtpressurehasincreasedthemarketpotentialandpublic
acceptanceofbothsources(BluefieldResearch,2015).
31 IWAALTERNATIVEWATERRESOURCESCLUSTER
Figu
re 5
.1 Sim
ple ‘m
ind m
ap’ d
epict
ing A
WR
optio
ns (b
lue),
som
e ge
nera
l cha
lleng
es (g
reen
) ass
ociat
ed w
ith e
ach
cate
gory
and
pot
entia
l solu
tions
(pur
ple).
32 IWAALTERNATIVEWATERRESOURCESCLUSTER
Table 5.1 Comparison of the average per unit costs and energy requirements of acquiring groundwater, surface water and several AWR options.
Resource option Average Electrical energy equivalent per m3
Average Cost per m3 Source(s)
Surface water ~0.36kWh(Worldwide) US$0.0003–0.40(Asia)
Gudeet al. (2010);Zhuet al.(N.D.)
Groundwater 0.14–0.24kWh(Worldwide)
US$0.05–0.07(Asia) Gudeet al.(2010);Zhuet al.(N.D.)
Brackish water RO 1.22–1.62kWh(NorthAmerica)
US$0.26–1.05(NorthAmerica,Europe)
Gudeet al.(2010);RaucherandTchobanoglous(2014);KaragiannisandSoldato(2008)
Seawater RO 2.0–4.5kWh(Worldwide) US$0.75–1.89(NorthAmerica)
Gudeet al.(2010);WateReuseAssociation(2012);RaucherandTchobanoglous(2014);Cornejoet al.(2014);Macharg(2011)
MSF desalination 13.5–25kWh(Worldwide) US$0.80–2.00(Australia)
Gudeet al.(2010);Wittholzet al.(2008);Cornejoet al.(2014)
Potable euse 0.84–0.92kWh(NorthAmerica)
US$0.66–1.62(NorthAmerica,Africa)
RaucherandTchobanoglous(2014);LahnsteinerandLempert(2007)
Non-potable reuse 0.27–0.42kWh(NorthAmerica)
US$0.25–1.59(NorthAmerica)
RaucherandTchobanoglous(2014)
Rainwater harvesting 0–0.1kWh(Worldwide) US$0–0.20(Vietnam,Tanzania)
Kimet al.(underreview)
Figure 5.2 Unit cost and energy consumption for various AWR (provided by Mooyoung Han).
25
24.8
13.6
13.4
4.6
4.4
4.2
2
2
1.8
1.8
1.6
1.6
1.4
1.4
1.2
1.2
1
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.20
0
Ene
rgy
requ
irem
ent p
er m
3 (K
Wh)
Cost per m3 (USD)
Groundwater
Surfacewater Rainwater
Potable Reuse
Non-Potable Reuse
Brackish water RO
MSF desalination (13.5~25KWh)
Seawater RO (2~4.5KWh)
33 IWAALTERNATIVEWATERRESOURCESCLUSTER
5.2 INFLUENCING FACTORS IN WATER SUPPLY SYSTEMS
Tocreateintegratedsolutionstoissuesofwaterscarcityandresourceuse,allrelevantfactorsmustbetakenintoaccount,
includingenvironmental,social,economicandpolitical/institutionalaspects.Acentralgoalofsustainablewatermanagement
istoreducethelikelihoodofscarcity,soitmustincludeday-to-daywateruseprovisions,aswellascontingencyplanningfor
droughts.
5.2.1 ENVIRONMENTAL FACTORS
Environmentalaspectsinfluencingwaterportfoliodecisionsmaybedifficulttoidentify,quantifyandmanage.Factorssuch
asgreenhousegasemissions,effluentdischarge,ecosystemfragility,biodiversity,waterpollution,salinisationofaquifersand
manyotherrelatedissuesmustbeconsidered.
Toensurethatminimalenvironmentaldamageoccurs,acomprehensiveenvironmentalimpactassessment(EIA)mustbe
completedtoassessallpossiblelocations,scalesandtechnologies,takingintoaccountwaterdemandandenvironmental
factors.Withthisinformation,partiescandeterminetheoperationalproceduresthatwillbestalleviatetherelevantregion-
specificwaterconcerns.Projectsmustalsobeperformedwithproperaccountingoftheenergyrequirementstoseehow
thesefallinwithnational(orinternational)commitmentstoenergyandemissionsproduction,orotherenvironmental
agreements,aswellasathoroughunderstandingandintegrationofthewater–energynexus(Schreineret al.,2014).
5.2.2 SOCIAL FACTORS
Socialfactorsaffectingwaterusemaybeoverlookedinfavourofeconomicfactors,buttheyareextremelyimportant.First
andforemost,decisionmakersmustrememberthatcleanwaterisabasichumanright,asdesignatedbytheUnited
Nations,andthiscannotbeignored(UnitedNations,2014).Alleffortsmustbemadetomakewaterfordrinkingand
sanitationavailabletoallpeople.Theethicaldimensionsofwatermanagementextendalsototheroleofwomen,whoin
manycountriesarethemainusersofdomesticwater,aremoresusceptibletowaterbornediseasesthanmen,andmust
fetchwaterfortheirhouseholds(UnitedNations,2005).Inregionswherewomenaremoreheavilyaffectedbywater
managementdecisions,theiropinions,ideasandwelfareshouldbeofcentralfocus.
Anotherimportantdimensionofthesocialfactorsofwaterportfoliosistheexistenceofsocialnormsaffectinglocal
behaviour.Inmanydevelopedcountries,the“mythofabundance”–whichleadspeopletobelievethatthereexistmorethan
sufficientnaturalresourcestosatisfyhumanneeds–isdeeplyrootedintheprevailingmindset,reducingthelikelihoodthat
themajorityofpeoplewillengageincertainconservationbehaviours.Societiesinwhichchildrenhavebeenraisedto
understandthatwaterisascarceresourcethatmustbeconservedaremorelikelytohavelowpercapitawaterdemands
andtorespondtodemandmanagementstrategies.Theseattitudesalsohaveasignificanteffectonwhetherornotwater
reusecanbeimplemented,sincewithoutpublicacceptance,suchprojectsareunlikelytobesuccessful.However,these
attitudesareunlikelytochangequickly,andmaytaketimetobeeffective.
5.2.3 ECONOMIC FACTORS
Economicfactorsareoftenastrongconsiderationfordecision-makerswhenmanagingthewatersupply,asfinancescanbe
ahighlylimitingfactor,particularlyintheearlystagesofaproject,whenpotentialeconomicbenefitshavenotyetbeen
accrued.Therefore,thesefactorsmayoftendeterminewhetheraprojectcanbeimplemented.
Beforeaprojectcanbeimplemented,acomprehensivecost–benefitanalysis(CBA)mustbecompleted.TheCBAmust
takeintoaccountboththecapitalandoperationalcostsofthedevelopment,thepotentialeconomicbenefitssuchasjob
creation,environmentalimprovement,reductionsinwateracquisitioncostsfromothersources,andastrategiclife-cycle
assessment(LCA)oftheproposedprojectagainstotherpotentialwatersupplyoptions(Schreineret al.,2014).Perhapsthe
mostdifficultaspectofassessingthecostsandbenefitsofwatersupplyprojectsistheactofenvironmentalvaluation,
whichcanbehighlysubjective.Valuingecosystemservicesandrecreationalusesoftheenvironmentoftenrequireindirect
valuationmethodsanddiscountingonfuturevalues,andmaynottakeintoaccountpositiveandnegativeexternalities.
Therefore,thesecalculationsmustbedonecarefully,andassignappropriatevaluetonaturalenvironmentalentities.
34 IWAALTERNATIVEWATERRESOURCESCLUSTER
5.2.4 POLITICAL/INSTITUTIONAL FACTORS
Goodgovernanceandpolicystronglysupporttheimplementationofgoodwatermanagement,butlegalandinstitutional
constraintstoportfoliomanagementmustbeaddressed.Legislativeprocessesmaybelengthy,withmultiplestepsinvolved,
whichcaninhibitapprovalofAWR-basedprojects.Theseprojectscanalsofailbecauseofstringentguidelinesregarding
waterreuseorothersimilarprocesses.Therefore,whenchoosingwatersupplyoptions,thelocalguidelinesmustbekeptin
mindsothattimeandfundsarenotwastedonprojectsthatwillprobablyberejected.
Fromagovernment’spointofview,agenciesshouldaimforprocessesandlegislationsthatsupportlong-term
sustainability,buildcapacityforfuturegrowthandencourageengagementofawiderangeofstakeholders.Bytakinginto
accounttheneedsandvaluesofallinterestedparties,governmentscanaidinthecreationofmoreholisticwaterportfolios
whilesimultaneouslygainingsupportfromthepublic.
Thedevelopmentofrelevantpolicyincentivestoensuretheintegrity,sustainabilityandregulatorycomplianceofall
phasesofprojectimplementationiscrucial(Schreineret al.,2014).AshasbeenmentionedearlierinthisCompendium,
peoplerespondtomonetaryincentives,andifindividualsorgroupsaremotivatedtocomplywithhealthandsafety
guidelinesanduseenvironmentallyfriendlypractices,thesafetyandreliabilityofwaterportfolioscanbesafeguarded.
35 IWAALTERNATIVEWATERRESOURCESCLUSTER
6 SHOWCASE OF AWR TECHNOLOGY
6.1 HONG KONG INTERNATIONAL AIRPORT
HongKongInternationalAirport(HKIA)–assessedinapaperbyLeunget al.(2012)–successfullyimplementedatriple
watersupply(TWS)systemthatincludesafreshwatersupplyforpotableuses,aseawatersupplytobeusedintoilet
flushingandairconditioning,anirrigationsystemusingreclaimedgreywater,andseparatecollectionsystemsforgreywater
andblackwater(Figure6.1).TheHKIAusesapproximately9,000m3perdayoffreshwaterforuseinfoodservices,aircraft
washing,andbathroomsinks.Ofthis,approximately4,000m3isreclaimedasgreywaterandusedforgardenirrigation
surroundingtheairport.
Figure 6.1 HKIA triple water supply (TWS) system (reprinted from Water Science & Technology 65 (3), 410–417 (2012) with permission from the copyright holders, IWA Publishing).
ThroughtheimplementationoftheTWSsystem,theHKIAhasbeenabletoreducetheirwaterdemandby52%.Ofthis,
41%isfromflushingtoiletswithseawater,4%isfromgreywaterreuse,andtheother7%isattainedbyplantingdrought-
tolerantgrassesandthusminimisingirrigationneeds(Leunget al.,2012).Thesystemalsoprovidesbenefitsintheform
ofenergysavings,mostlybecauseoftheminimaltreatmentneededtouseseawaterfortoiletflushingasopposedto
greywater.Table6.1showstheestimatedenergy,costandemissionsassociatedwithtreatingseawater,freshwaterand
reclaimedwaterfortheirrespectiveenduses.AccordingtothestudyofLeunget al.(2012),substitutingseawaterfor
reclaimedwatercansaveUS$240,000,1,600tonnesofCO2emissionsand2,800MWhofelectricityperannum.
Table 6.1 Energy consumption, electricity cost and emissions associated with treating three types of water for their desired end uses (reprinted from Water Science & Technology 65 (3), 410–417 (2012) with permission from the copyright holders, IWA Publishing).
seawater for toilet flushinga Freshwater 1 supplyb Reclaimed waterc
Energyconsumption(kWh/m3) 0.013–0.025 0.05 0.2–1
Comparison based on Airport Isle 7,600 m3/day: Island’s TWS system with flushingseawater flow of 7,600m3/day:Electricitycostd(US$thousand/year) 3.1–6.0 12 48–240Energyconsumption(MWh/year) 36–69 140 560–2,800CO2emissione(tonne/year) 21–40 80 320–1,600
ThereducedtreatmentcostsarenottheonlymonetarybenefitsassociatedwiththeTWSsystem.Althoughthecapital
costofimplementingthesystemwasaboutUS$70million–includingtreatmentplants,upgradeddistributionsystems,
seawatercoolingandtoiletflushingsystems–savingsperyearhasaveragedUS$3.8million,reducingthepaybackperiod
tolessthan20years.Includedinthesecostsavingsarethereductionsinelectricitycosts,freshwaterpurchased,and
sewageandtradeeffluentcharges(Leunget al.,2012).
36 IWAALTERNATIVEWATERRESOURCESCLUSTER
AlthoughsomeissueswiththeTWSsystemwereencounteredearlyon–particularlywithrespecttoseawatertoilet
flushing–thereplacementofuPVCpipeswithpolyethylenepiping,upgradingthematerialusedfortheflushingvalvesand
changingtheshapeofthetoiletbowlstomakethemmoreconducivetocleaningandmaintenancemadethesystem
functionmoreoptimally(Leunget al.,2012).OwingtothesuccessoftheTWSsystematHKIA,similarsystemsmaybe
feasibleforimplementationaroundtheworld,particularlyinlow-incomeandfreshwater-scarcecountrieswhereseawater
desalinationisprohibitivelyexpensive.
6.2 PERTH, AUSTRALIA: RO DESALINATION
Australiahasalonghistoryofdesalination,withitsfirstplantbeingbuiltin1903totreatsalinegroundwaterinthecountry’s
goldfields,anditspopularityrisingbetweenthe1960sand1980s(ElSalibyet al.,2009).Between2006and2013,six
large-scaledesalinationplantswerebuiltinAustraliainresponsetoprolongedperiodsofdroughtandincreasingwater
demands(Bosman,2014).
ThePerthSeawaterDesalinationPlant(PSDP)inthestateofWesternAustraliaisoneexampleofalarge-scaledrinking
waterdesalinationplant(Table6.2),whichwasfinishedin2006,producing144MLperdayoffreshwater(ElSalibyet al.,2009).Itsenergyefficiencyisexemplary,asitconsumesonly3.29kWhperm3thankstoanenergyrecoveryrateofabout
30%(Kemptonet al.,2010).Beforetheimplementationoftheproject,anenvironmentalimpactassessmentwasperformed
todeterminetheeffectsthattheplantwouldhaveonmarineorganisms,emissions,publichealthandsafetyrisks,noise,
surroundingvegetationandAboriginalculturalvalues.Aftertheextensivestudywascompleted,theproposedplantwas
deemedenvironmentallysound,andshortlyafteritsopeningitwasrecognisedastheworldstandardforthattypeofplant,
asitisthelargestdesalinationplantintheworldpoweredbyrenewableenergy(ElSalibyet al.,2009).
Table 6.2 Key operating data for Perth Seawater Desalination Plant (PSDP) (El Saliby et al., 2009).
Indicator Key data
Planttype SWROCapacity 140,000m3/dDesignexpansioncapacity 250,000m3/dSeawatertemperature 16–24°CSalinity 35.000–37.000mg/LEnvironmentalmonitoringrequired TDS,temperature,DO,sedimenthabitatProcessenergyrequirement 4–6–kW/m3
Contracttypes Designandbuild,operateandmaintainContractperiod 25yearsAnticipatedwatercost AUSSI.17/m3
Projectcost AUSS387MRenewableenergy Windfarmviagrid
Figure6.2showsaschematicofthedesalinationprocessatthePSDP,wherebyitpumpspre-treatedseawaterthrougha
seriesoffilters,addsananti-scalantbeforeitispumpedathighpressurethroughROmembranesandthenperforms
post-treatmentbeforeitisdirectedtoanearbyreservoir.
Australiaasawholehasdiversifieditswaterportfolioagreatdeal,activelyusingdemandmanagementtechniquessuch
aseducation,metering,water-savingdevices,low-impactdevelopment(LID)andpricingthat–tovaryingdegrees–reflects
thecostofproduction.Ithasalsoshiftedawayfromgroundwatersources,andincreasinglyusessurfacewater,RWHand
reusetechnology,aswellasdesalination,whileactivelyrechargingaquifers(Mollenkopf,2014).Infact,thecapacityof
desalinationandwaterreuseasaproportionoftotalwaterdemandhasbeensteadilyincreasing(Figure6.3).In2013,the
numberofwaterrecyclingplantsinAustraliawas165,withatotalcapacityof467GL,andthenumberofdesalination
plantswas82,withatotalcapacityof751GL(Radcliffe,2015).
37 IWAALTERNATIVEWATERRESOURCESCLUSTER
Figu
re 6
.2 PS
DP tr
eatm
ent p
roce
ss, f
rom
sea
wate
r int
ake
to d
ischa
rge
into
stora
ge re
servo
ir (E
l Sali
by e
t al.,
2009
).
38 IWAALTERNATIVEWATERRESOURCESCLUSTER
6.3 HYBRID CONSTRUCTED WETLANDS, CHINA
Constructedwetlands(CWs)havebecomeapopularnaturalmethodoftreatingwastewaterandstormwater,aswellas
creatingriparianbufferzonesandenhancingtheaestheticvalueofanarea.Theyarealsolow-costinbothenergyand
monetaryterms,makingthemfeasibleinbothdevelopedanddevelopingcountries.AninnovativehybridformofCWhas
beensuccessfullyimplementedinsouthernChina,ageneralschematicofwhichisdepictedinFigure6.4.ThisCWwas
designedtohaveasmallsize,makingitidealforsouthernChina,wherelandpricescanbeexorbitantlyhigh.Thehybrid
systemconsistsofavertical-baffledflowwetland(VBFW)andahorizontalsubsurfaceflowwetland(HSFW),aswellas
naturalaerationditches(NADs)toenhancethedissolvedoxygencontentofthedischargedwater,andanoptionalinternal
circulation(IC)system(Zhaiet al.,2011).
Figure 6.3 Total desalination and water reuse capacity in five major urban areas in Australia from 2006 to 2013, compared with the total urban water use in these areas (National Water Commission, 2014).
18001600140012001000800
GL
per
yea
r600400200
Adelaide desalination capacity
Melbourne recycled capacity
Melbourne desalination capacity
Sydney desalination capacity
South East Queensland recycled capacity
South East Queensland desalination capacity
Perth desalination capacity
Desalination and recycled water use*Total urban water use*
0
2006
–07
2007
–08
2008
–09
2009
–10
2010
–11
2011
–12
2012
–13
Figure 6.4 Hybrid constructed wetland schematic, overhead (top) and cross-sectional (bottom) view (reprinted from Water Science & Technology 64 (11), 410–417 (2011) with permission from the copyright holders, IWA Publishing).
Internal circulation (optional)
NADs
Section
Wetland cell
Clear waterpond
HSFWVBFW
Legend: Sampling points of pilot experiment
Septic tank Sediment pond
Reuse ordischarge
Reuse ordischarge
Rawwastewater
Rawwastewater
3 Baffles
3 Baffles
BaffleBaffle
BaffleBaffle
39 IWAALTERNATIVEWATERRESOURCESCLUSTER
TheuniqueshapesandfeaturesincludedintheVBFW+HSFWwetlandsystemallowittomakeoptimaluseofthe
relativelysmallvolumeofthewetlandbed,andtosimplifyitsoperation.Zhaiet al.(2011)conductedastudyindicatingthat
thesystemissuccessfulattreatingeffluenttomeetwaterqualityguidelineswithminimalcostsandenergyrequirements.
Onthebasisoftestresults,theaverageremovalefficiencyoftheCWsystemforCOD,suspendedsolids,ammonia
nitrogen(NH4+-N),totalnitrogenandtotalphosphoruswerearound84%,95%,72%,65%,and68%,respectively,
exceedingtheperformanceofeitherverticalorhorizontalflowwetlandsalone.
6.4 MADHYA PRADESH, INDIA
Mostgreywaterreuseprojectstendtobeinurbanandperi-urbanareasofdevelopedcountries,andarelessfrequently
exploredinruralareasofdevelopingcountries(Godfreyet al.,2010).However,giventherelativelylowpathogencontent
andhighavailabilityofgreywater,itoffersseveraladvantagesinthesesettings.Godfreyet al.(2010)examinedarural
greywaterreusesystem,whichwasimplementedinschoolsintheprovinceofMadhyaPradesh,India,andby2009was
operatingin300schoolsand1,500householdsowingtoitssuccess.Thesystemisrelativelysimpletoconstructandcan
bemadewithlocallyfoundmaterials.Itconsistsoffivestepstotreathouseholdgreywater,includingabsorption,
sedimentation,filtration,aerationandchlorination.AschematicofthesystemisshowninFigure6.5.First,soapandhairare
absorbedintothespongefilterbeforethewaterflowsintoasettlingtank,wherethesedimentationprocessallowsmost
solidstoberemoved.Fourfiltrationchambersfollowthesettlingtank,whichfilterthewaterwithprogressivelysmallergravel
substrates(from60mmtocoarsesand).Theaerationstageoccursaswaterisaidedbygravitythroughasteptank,and
thenitisstoredinacleanwatertank,wherechlorineisappliedtwiceperweek.
Figure 6.5 Cross-sectional (top) and overhead (bottom) view of greywater treatment system implemented in Madhya Pradesh, India (reprinted from Water Science & Technology 62 (6), 1296–1303 (2010) with permission from the copyright holders, IWA Publishing).
Thetreatedwaterisusedfortoiletflushingandwateringkitchengardens,andusersareeducatedtorefrainfromdirectly
wateringfruitandleafygreenswithgreywater,andtowashand/orcookvegetableswellbeforeeating.Godfreyet al.(2010)
assessedtheefficiencyofthesystembymeasuringfivekeyparameters(TSS,turbidity,BOD,CODandfaecalcoliform)in
boththeinfluentandtheeffluent,toseehowmanycontaminantshadbeenremovedintheprocess(Table6.3).Results
indicatethat–althoughtheeffluentwaterdoesnotmeetpotablestandards–itissafetousefornon-potableuses.The
authorsalsonotethatthesysteminquestioncanbeimplementedatanaffordablecost,thusmakingitoptimalforlow-
incomeareas.Notonlythis,butithelpstoalleviatesanitationissues,asmorewaterismadeavailablefortoiletflushing.
40 IWAALTERNATIVEWATERRESOURCESCLUSTER
6.5 TENORIO WASTEWATER TREATMENT PLANT, MEXICO
TenorioWastewaterTreatmentPlant(WWTP)inSanLuisPotosi,Mexico,wasthefirsttreatmentfacilityinMexicoto
producemulti-qualityrecycledwaterforavarietyofenduses.Giventhearidclimateoftheregionandover-pumpingofthe
twomainaquifers,freshwaterisminimal,andithasresultedinuntreatedwastewaterbeingusedforagriculturalirrigation.
TheTenorioWWTPusestherecycledwaterforagriculture,industrialuse(powerplant),environmentalenhancementand
groundwaterrestoration.Ithasbeensuccessfullyoperatingsince2006,savingoverUS$18millionfortheconnectedpower
plant(Lazarovaet al.,2014).
TenorioWWTPtreats45%ofthewastewaterfromthecityofSanLuisPotosi,andhasatotalcapacityof90,720m3per
day(Lazarovaet al.,2014).Theprimarytreatmentstepisappliedtoallincomingwastewaterandincludesinitialscreening,
removalofgritandgreaseandprimaryclarification.Afterthisstep,morethanhalfoftheprimarytreatedwaterisdischarged
totheTenorioReservoir–whichwasconvertedtoaconstructedwetland–toremoveorganicmatterandfaecalcoliforms
beforethewaterispumpedforagriculturalirrigation.Thewaterthatisnotallocatedtoirrigationundergoessecondary
treatmentbyactivatedsludgenitrogenremoval,followedbytertiarytreatmentwithsandfiltration,lime,softeningand
chlorinedisinfectiontobeusedforcoolingpurposesinanearbypowerplant(Lazarovaet al.,2014).Aschematicofthe
treatmentprocessisshowninFigure6.6.
Parameter Influent Effluent Efficiency; % or log removal
Suspendedsolids,mg/L 190 120 37Turbidity,NTU 142.5 80 44BOD5,mg/L 187,5 90 52COD(total)tmg/L 529.5 248 53Faecalcoliform,log 4.2–54Ulog/lOOmL 4–4.6Ulog/100mL+ 0.2–0,3
Table 6.3 Efficiency of greywater treatment system, based on five key water quality indicators (reprinted from Water Science & Technology 62 (6), 1296–1303 (2010) with permission from the copyright holders, IWA Publishing).
Figure 6.6 Schematic of Tenorio WWTP in San Luis Potosi, Mexico (reprinted from Journal of Water Reuse and Desalination 4 (1), 18–24 (2014) with permission from the copyright holders, IWA Publishing).
Grit and greaseremoval
Primary clarifierDensadeg
Lifting station 1
Liftingstation 2 Aeration tanks
Secondaryclarifiers
AgriculturalreuseTenorio
reservoir
Sand filtration Softening
Limetreatment
Coolingtower
in powerplant
Liftingstation 3
TheTenorioWWTPsavesabout7.9Mm3ofpotablewaterperannum,improvesthequalityofirrigationwaterand
provideswildlifehabitatthroughwetlandrestoration.Theprimarytreatmentprocessiseffectiveinremovingsuspended
solidsdowntoaconcentrationof82mg/L–whichisfurtherimprovedto28mg/Lafterwetlandtreatment–while
maintainingnutrientcontenttoallowreducedfertiliseruseinagriculture.Inadditiontothis,disinfectionoffaecalcoliformsis
ensuredwitha40dayresidencetimeintheCWsystem.Salinityisalsocontrolledtoreducetheriskofdamagingsalt-
sensitivecrops(Lazarovaet al.,2014).
AnecosystemmonitoringprogrammewassetuptoevaluateenvironmentalhealthinandaroundtheTenorioReservoir
sinceitsmodificationtoperformasawetland.Thestudyfoundthatthepresenceofthewetlandhasenhancedbiodiversity
intheregionbyattractingavarietyofmigratorybirds,aswellasincreasingthenumberofspeciesofsmallmammalsand
flora(Lazarovaet al.,2014).Finally,theprojectledtoseveralsocialandeconomicbenefitsinthearea,includingareduced
41 IWAALTERNATIVEWATERRESOURCESCLUSTER
incidenceofgastrointestinaldiseasesfromrawwastewater-irrigatedplants,economicbenefitsforfarmersandindustrydue
toamorereliablealternativewatersupply,improvedstandardsoflivingduetoacleanerenvironment,andconservationof
groundwaterresources(Lazarovaet al.,2014).
6.6 GOREANGAB RECLAMATION PLANT, WINDHOEK, NAMIBIA
TheGoreangabReclamationPlant(GRP)inWindhoek,Namibia,hasbeeninoperationsince1969,supplyingdrinking
waterthroughDPR.Theplantsuccessfullyensuressuitablewaterqualitywithmultiplebarriers,includingtreatment,
non-treatmentandoperationalmeasures.Theactualtreatmentprocessincludesacombinationofultrafiltration(UF),
activatedcarbonfiltrationandozonation(seeFigure6.7).
Figure 6.7 Technical schematic of Goreangab Reclamation Plant in Windhoek, Namibia (reprinted from Journal of Water Reuse and Desalination 5 (1), 64–71 (2015) with permission from the copyright holders, IWA Publishing).
pre-ozonationFeed
Q=24.000 m3/d
Cl2
ultrafiltration GAC GAC BAC
(DAF: dissolved air flotation, BAC: biological activated carbon-filter, GAC: granular activated carbon-filter)
ozonation
flocculation rapid sand filtrationflotation (DAF)
Someofthenon-treatmentbarriersincludethefollowing:
• divertingtradewastestoadifferentwatertreatmentplant;
• monitoringatboththeinletandoutletpointsofthefacility;
• constantmonitoringofpotablewaterquality;
• blendingofreclaimedwaterwithotherpotablewatersources;
• activecommunityengagementprogrammetoimprovepublicacceptance.
AlongwiththeGRP’streatmentprocesses–whichensurethatbetweenoneandfourbarriersareinplaceforeach
identifiedwaterqualityparameter–theaboveactionshelptoensurethatsafedrinkingwaterisobtainedfromtheplant
(Lawet al.,2015).
6.7 GUELPH, CANADA
TheCityofGuelphinOntario,Canada,isaprominentexampleofamunicipalityusingdemandmanagementstrategies
effectively.Asacitythatgets100%ofitsdrinkingwaterfromaquifers,theimportanceofconservingthatfiniteresourceis
crucial.In1998,theCitybeganaWaterConservationandEfficiencyStudy,followedbyimplementationofaWaterSupply
MasterPlanin2004(CityofGuelph,2009).
IncludedintheCity’sdemandmanagementmechanismsare(GreatLakesCommission,2015)thefollowing:
• rebatesonwater-efficienttoiletsandwashingmachines;
• Blue Built Homecertificationprogramme–basedonthepresenceofefficienthomefixtures;
• incentivesforinstallinghomegreywaterreuseorRWHsystems;
42 IWAALTERNATIVEWATERRESOURCESCLUSTER
• institutional,residentialandindustrial(ICI)auditandcapacitybuyback–paysusersforretrofitsthatpermanently
reducewaterconsumption;
• freeauditstoassesshomewaterandenergyefficiency,plusfreeretrofits;
• freeconsultationstoimprovegardenandlandscapewateruse.
ToiletandwashingmachinerebatesandtheICIcapacitybuybackaloneresultedinover400,000m3ofwatersavingsina
5-yearperiod(CityofGuelph,2009).
Overall,Guelph’swaterconservationprogrammeshaveresultedinsavingsofaround10,000m3perday,despitea
15,000personpopulationincrease(GreatLakesCommission,2015),makingthepercapitawateruseoftheaverage
Guelphresidentnearlyone-thirdlowerthanthatoftheaverageCanadian(CityofGuelph,2013).NotonlyistheCity
conservingfreshwater,buttheirdemandmanagementprogrammeshaveresultedinfinancialbenefitsofclosetosixtimes
theinitialinvestmentinavoidedsupply,capacityandwastewatercosts(Table6.4).
Table 6.4 Present value of total costs and benefits of each City of Guelph demand management strategy (Great Lakes Commission, 2015).
Activity Name PV Cost ($) PV Benefit ($) NPV ($)
RoyalFlushToiletRebate,SF $1,676,300 $12,068,155 $10,391,855RoyalFlushToiletRebate,MF $525.400 $2,534,944 $2,009,544RoyalFlushToiletRebate,IQ $55,600 $441,405 $195,605SmartWashWashingMachineRebate $1,333,250 $4,506,374 $3,473.124BlueBuiltHome-Bronze $329.2S0 $545,125 $215,546BlueBuiltHome-Silver $15,900 $21,467 $5,587GreywaterReuseSystems $21,000 $3,157 $(17,843)ICIAuditandCapacityBuybackProgram $967,395 $12,323,719 $11,356,324RainwaterHarvestingSystem $50,000 $7,264 $(42,736)HealthyLandscapeVisit $368.970 $36,022 $(332,948)EfficientHomeVisitSurveys(GEL/NetZeroCity) $229,505 $24,127 $(205,378)Total $5,572,800 $32,811,780 $27,238,980
Byimplementingawidevarietyofdemandmanagementstrategies,aswellasencouragingsmall-scaleacquisitionof
AWRthroughgreywaterreuseandRWH,theCityofGuelphdisplaysexemplaryunderstandingofintegratedwatersupply
management.
6.8 BORA BORA, FRENCH POLYNESIA
TheFrenchPolynesianislandofBoraBorawasexperiencingincreasingwatershortagesduetodwindlingrainfall,increased
developmentandalargetourismsector.Sincetheexistingfreshwaterresourcesontheislandwerenotsufficienttomeet
theneedsofpermanentresidentsplusthelargeinfluxoftourists,itwasimperativethatwaterreuseanddesalinationbe
implemented.Additionally,thelagoonecosystemstypicalofFrenchPolynesiaarefragile,andthedischargeofuntreated
waterposesaseriousrisktolocalfloraandfauna,creatinganotherincentivetoreusewater.BoraBorafinallyputawater
recyclingprogrammeintoplace,butseveralconstraintshadtobeaddressedtoensurecommunityacceptanceofthe
programme(Lazarovaet al.,2012).
Twowastewatertreatmentplantshavebeenimplementedontheisland,usingUFtotreatreclaimedwatertoEuropean
standardsforbathingwater(Table6.5).Therecycledwaterisstoredinacoveredreservoiraftertreatment,thenchlorinated
andpumpedthroughanon-potabledistributionnetwork.In2010,solarphotovoltaicenergywasappliedtoimprovethe
overallenergyefficiencyoftheprogramme.DesalinationisalsobeingutilisedinBoraBora,withthreeROplantshaving
beenimplementedsince2000(Lazarovaet al.,2012).
AccordingtoLazarovaet al.(2012),themainapproachtoincreasingpublicacceptanceofwaterreuseinBoraBorawas
communityconsultation,whichincludedthefollowing:
• publicforumsandinterestgroups;
• consultinginterestgroupsandholdingworkshops;
43 IWAALTERNATIVEWATERRESOURCESCLUSTER
• educationprogrammesindicatingthesafetyofthereusescheme,aswellastheneedforsuchaprojectgiventhe
waterconstraints;
• collaborationwithmediatomarketreclaimedwaterasasustainablesolution.
Asaresultofthesepublicengagementinitiatives,demandforreclaimedwaterinBoraBorahasincreased,ashasthe
numberofend-users,whichdoubledaftertertiaryUFtreatmentwasimplemented.Recycledwaterisnowusedforboat-
washing,landscapeirrigation,fireprotection,industrialuses,large-scalecleaningandothernon-potableuses(Lazarova
et al.,2012).
Inadditiontocommunityconsultationprocesses,pricingmechanismswereputintoplace,consistingoffixedand
volumetriccostschosentoreflectthewillingness-to-payofconsumers.BoraBoraputinplaceatwo-partpricingstructure
withadecliningblockratewithlowerperunitpricesthanpotablewater.Largeend-usersandtourism-relatedbusinesses
helpedtoincreasepublicacceptanceofreusedwaterbyprovidingfundingtothereuseindustry,whichhelpedtokeep
costslowforsmallconsumers(Lazarovaet al.,2012).
AsaresultofBoraBora’sexpandedwaterportfolio,freshwaterresourcesarebeingconserved,thelagoonenvironmentis
beingprotected,businessesarereapingeconomicbenefits,andthecommunityasawholeisadoptingandacceptingmore
sustainablepractices.Inadditiontothefacilitiesalreadyinplace,BoraBorawouldliketoextendtheoperationtoincludea
morewidespreadnetworkoffireprotectioninfrastructureandaUF/ROmembranefacilityfortheproductionofpotable
water(Lazarovaet al.,2012).
6.9 KOGARAH, SYDNEY, AUSTRALIA
AsuccessfulexampleofadualRWHandstormwatercollectionsystemisbeingusedinthetownsquareofKogarah,a
suburbofSydney,Australia,adepictionofwhichisshowninFigure6.8.Stormwaterrunofffirstflowsthroughagross
pollutanttrap(GPT)toremovelargerparticlesandlitter,beforebeingcollectedinastoragetankfor“dirty”water.Itis
storedthereuntilitisreadytobeusedforirrigationofgreenspacesinsurroundingcourtyards,whichactasbio-filtersand
removesomeofthefinerpollutants.Itiscollectedonceagainafterithaspercolatedthroughthebio-filterandstoredina
“clean”watertank,locatedadjacenttothedirtywatertank(Chananet al.,2010).
Alsocollectedinthecleanwatertankisrainwaterfromrooftops.Thiswaterisusedfortoiletflushingandcarwashing,as
wellastotopupothertankswhenwaterlevelsarelow.Eighty-fivepercentofprecipitationthatfallsonthesquareisused
intheareathroughthedescribedsystem.Itisestimatedthatbetweenthereuseofrainwaterandstormwater,approximately
7,920kLofpotablewateraresavedannually(Chananet al.,2010).
Totreatstormwaterfromthelargercatchmentarea,a9,500m2constructedwetlandwasalsoimplementedinKogarah,
which–incombinationwithaGPT–treats95%ofstormwaterrunoffinthecatchment.Stormwaterentersthewetlandat
oneendwherethe2mdepthallowssedimentsandheavymetalstosettleandremainundisturbed;thenflowsthrougha
shallowsectioninthemiddlewheremacrophytesarepresenttoaidinnutrientfiltration;andfinally,thebreakdownof
bacteriaisaidedinafinal,deepersectionbysunlightandwind.Aftertheentireprocessiscompleted,anoutletpipecarries
thetreatedstormwatertoOatleyBay,apopularrecreationarea.Theconstructionofthiswetlandhasdrasticallyimproved
Parameter Raw sewage
Secondary effluent Recycled water (UF permeate)
Measured Consent Measured Guide value
COD(mg/L) 595(270–837) 31(21–65) 90 15(4–34) 40BOD5(mg/L) 349(200–540) 7(<5–22) 25 4(1–6) 20TSS(mg/L) 238(125–275) 9.5(4–19) 35 <5 20Ntot(mg/L) 47(30–70) 8.3(2–18) 20 7.3(2–17) 20Ptot(mg/L) 6.8(4.1–8.1) 2.5(1.0–5.8) – 1.9(0.45–5.8) –E. coli/100mL ND 105–107 – Non-detected 0/100mL
aAveragevalueandlimitofvariations(monthlycompositesamples,excludingE. coli.thatwasmonitoredingrabsamples).
Table 6.5 Measurement of water quality indicators at several stages in the treatment process, from raw sewage to treated recycled water (reprinted from Journal of Water Reuse and Desalination 2 (1), 1–12 (2012) with permission from the copyright holders, IWA Publishing).
44 IWAALTERNATIVEWATERRESOURCESCLUSTER
thequalityofstormwaterabovepre-constructionlevels,whichwerepreviouslyveryhighinheavymetalsandotherpollutants
(Chananet al.,2010).
6.10 STAR CITY, SEOUL, SOUTH KOREA
Inoperationsince2007,StarCityisalargereal-estatedevelopmentinasuburbofSeoul,SouthKorea,thatishometo
morethan1,300apartmentsinfourhigh-risebuildings.ThedevelopmentfeaturesaninnovativeRWHsystemthatisused
simultaneouslyforfloodprevention,waterconservationandemergencyresponsepurposes.Thesubjectofworldwide
acclaim,itssuccesshasresultedinothercitiesacrossSouthKoreaimplementingsystemsofsimilardesign.HanandMun
(2011)collected2yearsofoperationaldatafromStarCitytoassesswaterandenergysavings,waterqualityandrunoff
control.
AschematicoftheStarCityRWHsystemisdepictedinFigure6.9.Thetotalroofcatchmentareais6,200m2ofrooftop
and45,000m2ofterrace,andthestoragecapacityis3,000m3ofwaterstoredinthree1,000m3tanks.Twoofthethree
tanksstorerainwatercollectedfromrooftopsaswellastheground;thiswaterisusedforgardenirrigation,andisthen
recycledandstoredforfurtheruse.Thethirdtankholdstreated,emergencytapwater.Theissueofthistank’swaterquality
deterioratingovertimeisaddressedbypumpinghalfofitsvolumeintooneoftherainwatertanksatregularintervalsand
replenishingitwithafreshsupply.Screensandfiltersarepresentattankinletstomaintainquality,andcalminletsand
floatingsuctiondevicesareusedtoavoidre-suspendingsediments(HanandMun,2011).
Uponanalysisofthesystem,HanandMun(2011)foundthatitconservesavolumeofapproximately26,000m3peryear
ofpotablewater,whichiscloseto50%ofthetotalprecipitationthatfallsovertheareaoftheStarCitycomplex.By
recyclingirrigationwateraswellasstoringunusedwaterfromonemonthtothenext,thesystemisabletomaintainfairly
consistentusagethroughouttheyear.AllwatertestedinthestudyhadturbiditylevelsbelowtheKoreanGrayWater
Standard(KGWS)(<1.5NTU)andpHwithintherangespecified(6–8.4)intheKoreanDrinkingWaterStandard(KDWS).
HanandMunalsoassessedtherunoffcontrolpotentialofthesystem,whichisillustratedinFigure6.10.Thetankvolume
tocatchmentarearatioofthesystemis5.8m3/100m2,meaningthatintheeventofa50-yearstormwithapeakflowof
Figure 6.8 Flows through Kogarah RW/SW harvesting system. Included components are “clean” water for toilet flushing (light blue), rooftop-harvested rainwater (medium blue) and stormwater (dark blue) (reprinted from Water Science & Technology 62 (12), 2854–2861 (2010) with permission from the copyright holders, IWA Publishing).
45 IWAALTERNATIVEWATERRESOURCESCLUSTER
27m3/hour,theStarCitytankcouldreducethepeakflowdischargeto20m3/hour,equivalenttoa10-yearstormevent.
StarCityisalsoestimatedtosaveapproximately8.9MWhofelectricityeveryyear,owingtothereducedneedforthe
treatmentandconveyanceofpotablewater.
6.11 DECENTRALISED WATER REUSE WITH ZERO DISCHARGE, CHINA
AwaterreclamationandreusesystemwasdesignedandinstalledinXi’anSiyuanUniversitylocatedinthesoutheast
suburbanareaofXi’anCity,China.AsshowninFigure6.12,watersupplyinthisuniversitydependedongroundwaterwells
withacapacityof2,800m3perday;whichcouldmeetthedemandforpotableusesforupto35,000studentslivinginthe
campus,butwasinsufficientforcoveringallthenon-potableconsumptionasprojectedinTable6.6(Wanget al.,2015).
Afterpotableuse,thecollectedusedwaterissenttotheon-campustreatmentstationwhereasophisticatedprocess
(Figure6.11)isusedforwaterreclamationbycombiningananaerobic–anoxic–oxic(A2O)unitwithamembranebioreactor
(MBR)fortheproductionofhigh-qualityreclaimedwater.Toenlargethesourceforwaterreclamation,thereclaimedwater
–afterbeingusedfortoiletflushing–isalsocollectedandaddedtothetreatmentstationinflow.Asaresult,thepotential
ofreclaimedwaterproductionbecomeslargerthantheoriginalgroundwatersourceandeverydropofusedwaterisadded
Figure 6.9 Star City, South Korea, RWH system schematic (reprinted from Water Science & Technology 63 (12), 2796–2801 (2011) with permission from the copyright holders, IWA Publishing).
Ground surface Man-hole
Man-hole
Man-hole
Man-hole
RoofcatchmentFrom emergency tank
Tapwater
Store for Emergency Collect fromground surface
Collect fromroof catchment
Fourth below-ground floor in Building B
M.H
Filter
Figure 6.10 Runoff control potential for flood events from 5 to 100 years in magnitude, according to RWH tank volume (reprinted from Water Science & Technology 63 (12), 2796–2801 (2011) with permission from the copyright holders, IWA Publishing).
35
30
Qpe
ak (
m3 /h
r)
25
20
15
10
5
0
0 1 2 3 4 5 6 7 8 9 10
Tank volume (m3/100m3)
11 12 13 14 15 16 17 18 19 2055.8
5 yearDesign periods
10 year30 year50 year100 year
46 IWAALTERNATIVEWATERRESOURCESCLUSTER
tothesourceforwaterreclamation,insteadofbeingcategorisedas‘waste’tobedischarged(Huet al.,2013;Wanget al.,2015).
AnoticeablefeatureofthesystemshowninFigure6.12istheintroductionofaso-called‘environmentallake’,which
performsthefunctionsofbothwaterlandscapingandstorage.Multi-stepwaterusehasalsobeenrealisedbysupplying
reclaimedwater,firstlytoaseriesofwaterlandscapesbeforethelake,andthenpumpingwaterfromthelakeforoutdoor
gardeningandindoortoiletflushing.Therefore,thehydraulicretentiontimeofwaterinthelakeisdynamicallycontrolledat
about5–7dayswithoutadditionalwaterconsumptionforitsreplenishment.Agreencampushasthusbeencompletely
nourishedbysufficientreclaimedwaterthroughazerodischargeandefficientwaterreusesystem(Wanget al.,2015).
6.12 SCHOOL DRINKING WATER SUPPLY IN HANOI, VIETNAM
CukheElementarySchoolislocatedinCukheVillage,inthesouthernpartofHanoi,Vietnam.Theschoolhas300students,
15teachersand3buildingswithrelativelysecureandsuitableroofs.Inthepast,theyhavehadtouseexpensivebottled
Figure 6.12 Configuration of the campus water reuse system (Wang et al., 2015).
Figure 6.11 The used-water treatment and reclamation process (Hu et al., 2013).
Table 6.6 Projection of non-potable water demands (Wang et al., 2015).
Water use Specification Quantity Demand Remarks
1 Toiletflushing 30L/d/person 25,000–35,000persons 750–1050m3/d2 Gardening 3L/m2/d 50,0000m2 1500m3/d For50hectaresgreenbelt3 Lakereplenishment 20%daily
replacement50,000m3 1000m3 Forlakesof5,000m2and
1mdepth4 Lakewaterloss 20%oflake
replenishment1,000m3 200m3 Evaporationandotherloss
5 Total 3,450–3,750m3/d Includingitem32,450–2,750m3/d Excludingitem3
47 IWAALTERNATIVEWATERRESOURCESCLUSTER
waterfordrinkingbecauseofarseniccontaminationinthelocalgroundwater.InJuly2014,anewapproachwasintroduced
andtheLotteDepartmentStoredonatedmoneyforarainwatersystemaspartofitscorporatesocialresponsibility(CSR)
commitment.AteamfromSeoulNationalUniversity(SNU)designedthesystem,whichconsistsofa180m2roof
catchment,gutter,firstflushtank,two6m3rainwaterholdingtanks,andUVfiltersnearthetap(Figure6.13).Localpeople
usinglocallysourcedmaterialsconstructedthesystem,andfollowingconstruction,boththeresidentsandthedonor
companyweresatisfiedwiththeoutcome.Waterlevelgaugesandwatermeterswereinstalledtomonitorremainingwater
suppliesandcumulativewaterconsumption.About6m3rainwatercanbesavedfromtheRWHfacilitiespermonth,which
meansUS$150canbesavedmonthlyasaresultofnothavingtobuybottledwater.Thisisequivalentofbuildinganother
community-basedRWHsystemevery2years(US$3,600).
Figure 6.13 Rainwater tank at Cukhe Primary School, Vietnam (provided by Mooyoung Han).
Catchment
Kindergarten 150 m2 6,000L × 2 = 12,000L
School Area Volume of Tank
PrimarySchool
80 m2 5,000L × 2 = 10,000L
Filter
First Flush
First Flush
Tap
Drain
Water Meter
Vent
Drain Drain
Drain
Calm-inlet
Vent
InflowScreen
Overflow
Figure 6.14 The rain gauge installed at Cukhe Primary School, Vietnam.
Anotherprominentissueintheareawasinsufficientrainfalldata,asmostrainfalldataarecollectedinurbancentres.
Therefore,CukheVillagedidnothaveadequaterainfalldatatomakeapreciseRWHdesign.Thesolutionwastoinstalla
simplerainfallgaugeandworkwithagroupofsciencestudentstomaintainrainfallrecordsviaawebsite(Figure6.14),
whichtheycanthenuseinfuturedesigns.
Thelessonslearnedfromthiscasestudyarethreefold:theimportanceofbuildinglocalresidents’capacitytodesign,
build,andoperateRWHsystems;theimportanceofinvolvingindustrythroughCSRactivitiesasawin–winstrategy;and
thebenefitoflocaldatacollectionbystudents,whichresultedindemocraticdesigndecisionsthatcanbeusedas
referenceforfuturedesignsandoperations.
48AlternAtiveWAterresourcescluster
7 KNOWLEDGE AND TECHNOLOGY GAPSThe following section and section8 incorporate ideas and recommendations from experts in AWR-related fields. All the knowledge contained in these sections is that of the contacted professionals, unless a different source is cited. Individual contributors are listed in the document under “Key Contributors”.
DespitemanypromisingtechnologiesemerginginAWrsectors,therestillexistsomeprominentgapsinthepresent
knowledge,practicesandtechnology.someexamplesofthesegapswillbeidentifiedandexplainedinthissection.
7.1 DATA COLLECTION AND INTEGRATION
today,mathematicalmodellinghasbecomefundamentalfornaturalresourcesmanagement,inparticularforwaterresources.
Governmentalagenciesrelyonmodelstomanagecurrentconditionsandforecastfuturestrategies.However,gapsstill
exist–particularlyinlessdevelopedcountries–inwhichinformationareroughlycollectedandrarelymadepublicina
completeform.
thelackofconsistentdatainthewatersectorcanleadtopoorunderstandingofthepresentconditionsand
effectivenesswatermanagementplans,alackoftrustfromthepublicanddifficultycomplyingwithregulations.Freeand
opendata,availabletoresearchinstitutesandcitizens,helptoclarifycurrentwaterresourcesconditionsandincreasesocial
awareness.effortsmustbemadeattheinternationalleveltodevelopacommonnetworkfordatapresentationand
interpretation.notonlythis,butsocial,economic,healthandengineeringdatashouldbeintegratedunderacommon
frameworktomakescience-basedandrisk-baseddecisions.thistypeofframeworkcurrentlydoesnotexist,butis
necessaryforcreatingsaferandmorerobustwatersupplysystems.
7.2 FRAMEWORK FOR ASSESSING CASE-BY-CASE SCENARIOS ON THE BASIS OF ENVIRONMENTAL IMPACT AND COST-EFFECTIVENESS
eachwaterdeficientsituationneedsanoptimisedsolution,butacommonsolutionforeverycasedoesnotexist.the
fundamentalpointistofindanoptimalsolutiontailoredtoeachindividualscenariothatcompromisesbetweensocial,
economicandenvironmentalobjectives,whilekeepinginmindsustainabledevelopmentgoals.
thereisapresentlackofacomprehensiveframeworkorguidancetoolforselectingspecifictechnologiesand
managementstrategiesthatcanbeadaptedonacase-by-casebasis.thecreationofsuchadocumentisessentialto
makingdecisionsthatwillbesustainableinthelong-run.thisisespeciallyimportantintheAWrsector,wherenew
technologiesareconstantlyemergingandmaynotyethaveundergonewidespreadimplementationorhadtheopportunityto
buildareputation.thereisstillconsiderableroomforimprovingknowledgeofcostandenvironmentalsolutionsthatare
effectiveandreliableovertime.
7.3 MORE EFFECTIVE AND RELIABLE WATER SOLUTIONS FOR ARID CLIMATES
thecreationofsafeandreliablewatersuppliesinaridregionsisstillagreatchallengearoundtheworld.Areaswithout
sufficientgroundandsurfacewatertomeettheirneedsmayexperienceareducedqualityoflifeiftheylackthecapacityto
obtainwaterfromelsewhereortoharnessAWr.Moreattentionisneededincreatingsolutionsthatincreasewater
availabilitywherefewoptionsareavailable,anddosoinawaythatcanbeadjustedtofittheeconomicandenvironmental
capabilitiesoftheregioninquestion.thismayinvolvecreatingmoreeffectivewaterstoragesolutions,implementing
high-efficiencywaterreuseschemes,utilisingwater-savingtechnologyorsubstitutingprocessesthatusewaterforonesthat
donot.
thisneedalsoappliestoregionsinwhichdryseasonwaterneedscannotbemetbywatermadeavailableinthewet
season.Forexample,problemsstillexistwithmanagingcollectedrainwatereffectivelyfromthewettodryseasons.often
thereisstillnotadequatestoragecapacitytoprotectagainstsignificantdryseasonshortages.tomitigatetheseissues,a
shiftinconsumptionpatternsmustoccursothatlowerratesofutilisationoccurinthedryseason(Mwamilaet al.,2015).
49AlternAtiveWAterresourcescluster
theimplementationofadualwatersupplythatusesrainwaterfordrinkingandreclaimedwaterfornon-potableuses
wouldhelptoslowtherateofdepletionofexistingfreshwatersources.engineeringsimulationsshouldbeconductedforthe
optimaldesignofthiskindofsystem(nguyenandHan,2014).
7.4 HIGH RATES OF WATER LOSS
Amajorproblemaffectingwaterutilitiesaroundtheworldisthehugeamountofwaterbeinglostfromwatersupplyand
distributionnetworks.Ahighlevelofwaterlossisaproxyindicatorofapoorlyrunwaterutilityreflectinghugevolumesof
waterbeinglostthroughleaksornotbeinginvoicedtotheconsumers,orboth.theWorldBankconservativelyestimated
thatthewaterlostdailyacrosstheworldthroughleakageinthedistributionnetworkswouldbesufficienttoservenearly
200millionpeople.inaddition,30millionm3aredeliveredeverydaytocustomers,butarenotinvoicedbecauseof
pilferage,corruption,andpoormetering(Kingdomet al.,2006).
Waterlossreductionwouldhaveanimmediateoperationalandfinancialbenefittothewaterutilities,andthisshould
capturetheattentionofallconcernedparticularlylocalauthoritiesandgovernments.reducingwaterlossesrepresentsa
cheapAWr,whichcanbeprovidedatamuchlowercostthanotherviableoptions.thecontinuouslyrisingcostof
producing,treating,transporting,storinganddistributingwaterpresentsnewopportunitiesforthecreationofinnovative
strategiesandtechnologies.solutionsmustbeprovidedtotheproblemsofexcessiveleakage,inaccuratebilling,network
inefficiency,excessiveenergyuse,etc.
7.5 LACK OF PUBLIC ACCEPTANCE OF RECLAIMED WATER
oneofthemajorchallengesrelatedtotheuseofreclaimedwaterishowtoovercomethepsychologicalbarrierassociated
withthistypeofuse.Manytechnologiesexistwhichcanproducesafeandreliablereclaimedwater,butitstillcarriesan
inherent“yuckfactor”whichmustbeovercomebeforewidespreadimplementationcanbefeasible.thisbarrierdoesnotjust
existinregardstopotableuse.theuseofreclaimedwaterforbathing,laundry,carwashingandevengardeningcan
becomeproblematicwhenusersdonottrustitssafetyorquality.
overcomingthisobstaclerequirestheuseofawarenessprogrammestargetedateducatingthepubliconthesafetyand
treatmentprocessesofreclaimedwater.evenwiththesekindofprogrammes,publicacceptancecanbeslow,andtherefore
long-termstrategiesmayneedtobeused.safeandsuccessfulwaterreusetechnologiesshouldbemadevisibleto
enhancethetrustandacceptanceofcommunities.
7.6 SAFETY AND SUSTAINABILITY IN TRANSPORTATION
transportationofwateriscriticaltothefunctioningofallwatersupplysystems.However,multipleissuescanarisein
transportation,particularlywithregardstoitssafetyandsustainability.
ifalternativewatersourcesareassociatedwithdifferenttypesofuse(i.e.potableandnon-potable)sharingthesame
space,theriskofcrossconnectionsisanissue,particularlybecausethesearetypicallyburiedpipes.thisriskofcross
contaminationmayhavesevereconsequences(e.g.publichealth).colourcodesforthepipesorsimilarsolutionsdonot
provideahighenoughlevelofsafetyandotherexistingsolutionsbringaddedcoststoconstructionandmaintenanceofthe
networks.thereneedtobeasmanynetworksastherearedifferentwaterqualitytypes,andtheseneedtocoexistwith
minimalcrossconnectionrisk.Morecreative,effectiveandcost-efficientsolutionsareneeded.
Manyexpertsinthewatersectorhavealsorecognisedthattransportingwaterlongdistancesmaynotbesustainablein
thefuture.Firstly,theactofpumpingwatertoanotherregionusuallyrequiresagreatdealofenergy,andthereforecanbe
cost-intensiveandemissions-intensive.Further,relyingonwaterbeingpumpedfromadistancemaycauseproblems,
particularlyinthecaseofanemergency,naturaldisasterorsignificantwatershortage.Plansshouldbemadewhichtake
intoaccountthepossibilityofunforeseencircumstancesandincorporateappropriatecontingencyplanningclauses.
50 IWAALTERNATIVEWATERRESOURCESCLUSTER
8 RECOMMENDATIONS
8.1 AWR VISIBILITY
ItisimportanttomakeAWRmorevisiblewithinthefieldsofscience,engineering,politicsandbusinessaswellaswiththe
generalpublic.Spreadingknowledgeandunderstandingofnewtechnologieswillhopefullyincreasepublicacceptanceand
promotetheirusewithinwatersupplysystems.
AgoodwaytopromoteAWRistopresentvaluablecasestudiesinwhichthedesiredgoal(s)hasbeenreachedanda
moresustainablewatersupplyhasbeencreated.Scientists,techniciansandcitizenscanusetheirrespectivework,
knowledgeandexperiencetoimprovethevisibilityofsustainableprojects.Networksshouldbecreatedbetweendifferent
sectorsofsocietyandacommonspaceshouldbefoundinwhichtocreateatransparentandopenframeworkforthe
developmentofAWRprojects.
Tobuildcapacityandmomentum,implementationmaystartsmall,suchaswithhousehold-scaleRWHorgreywaterreuse
systems,focusingontheeducationandskilldevelopmentofusers.Thisisabottom-upmethodofincreasingawarenessand
understandingofAWRoptions,andmakingthegeneralpublicmoreinvestedincreatingsustainablewatersupplies.
InadditiontoincreasingthevisibilityofAWR,therationalebehinditsimplementationshouldbewell-known.AWRasan
optionforcreatingmoresustainablewatersupplieswouldbenefitfrombeingmoreprominentineducation,andthevalueof
waterinenvironmental,economic,culturalandsocialcontextsmaybetaughttochildrenfromayoungagetoensurethat
theseprinciplesareunderstoodwellinfuturegenerations.
8.2 TECHNOLOGICAL ADVANCEMENT
Thedevelopmentofadvancedtechnologiesforwatermanagementshouldbeongoingandhighlyvalued.Thewatersector
hasseenmuchimportanttechnologicaladvancement,whichhasallowedtheprovisionofhigherqualitywateratalower
costandwithlessimpactontheenvironment.However,thesetechnologiescanalwaysbeimprovedtomakethemmore
efficient,reliable,cost-effectiveandenvironmentallyfriendly.
Forexample,theuseofrenewableenergyinwatertreatmentisbecomingincreasinglypopular,andimprovingthe
reliabilityandefficiencyofthesetechnologiescouldhavelargebenefitsforthewatersectorandtheenvironment.
Additionally,RWHhasbeenaroundforcenturies,buttechnologicalimprovementscontinuetomakeitmoreableto
effectivelyaugmentthewatersupply.Makingthesesystemsmoreautomated,low-maintenanceanduser-friendlymayhelpto
promotewidespreadimplementationofsmall-scalesystems,whichtogethercansavevastamountsofpotablewater.
Waterlossmanagementisalsoafieldinwhichtechnologicaladvancementcurrentlyhasandwillcontinuetohaveagreat
impactontheefficiencyofwatersupplysystems.Someoftheareasinwhichtechnologyhasbeenadvancingandfurther
workiscurrentlybeingundertakenarewaterqualitysensors,communicationequipment,datamanagementsoftware,
real-timesupervisorycontrolanddataacquisitionsystems,remotecontrolofequipmentsuchaspumpsandvalves,automatic
meterreading,etc.Broadareasinwhichcontinueddevelopmentoftechnologieswouldenhancefurtherimprovementof
waterdistributionnetworksincludesmartmetering,waterquality,energyefficiency,leakagemanagementanddataanalysis.
Althoughmuchofthisknowledgeisalreadyavailable,applyingiteffectivelyandwithproperforesightisimportant.
8.3 FRAMEWORK FOR AWR ASSESSMENT
TherecurrentlyexistnoclearlydefinedmetricsforquantitativelymeasuringandcomparingdifferentAWRoptions.For
example,itmaybepossibletomeasurethecostsandbenefitsoftwodifferentdesalinationschemes,buthowwouldone
definitivelychoosebetweenawaterreuseschemeandonethatusesdemandmanagement,takingintoaccountthe
life-cyclecosts,benefitsandoverallsustainabilityandresiliencyofeachsystem?
AcomprehensiveframeworkforbenchmarkingAWRtechnologiesandstrategiesisneeded.Thisframeworkwillinclude
toolsforquantitativelyandqualitativelyassessingwatermanagementstrategies.Thiswillaidinthedecision-makingprocess
andcontributetothedevelopmentofamorereliableandsustainablewatersupply.TheAWRClustercouldplayacrucial
roleinthedevelopmentofsuchaframework.
51 IWAALTERNATIVEWATERRESOURCESCLUSTER
8.4 SYSTEM RECONFIGURATION
Aparadigmshiftshouldoccur,withrespecttothewayurbanwatersystemsaredesigned.Newsystemswouldbenefitfrom
havingenclosedwatercycleswithminimalfreshwatersuppliedandminimalwastedischarged(seeexampleinFigure8.1).
Toaccomplishthis,subsystemsofurbanwatercycles(e.g.,supply,sewerage,reuseandenvironment)shouldbe
harmonicallyintegratedintoacombinedframework.Inthisframework,wastewatershouldbeviewedasaresource,and
naturalorartificialwaterbodiesshouldbeanimportantpartofthesesystems,tobereplenishedandusedforwaterquantity
regulationandwaterqualitypolishing(Wanget al.,2015).
Figure 8.1 A cyclical urban water supply, in which resources are recovered to the furthest extent possible, discharge of waste is minimised and natural and artificial water bodies are used as buffers (Tambo et al., 2012).
Insustainablewatersystems,WWTPsshouldbeconceivedlessaspollutioncontrolsystemsandmoreasresidue
valorisationsystems.Manyeffortsarecurrentlymadetorecoverresourcesbothinthewaterandinthesludgelines.Biogas
productionandvaluablechemicalsrecoveryarejustsomeofmainfoci.Theseeffortsshareacommonbackground:the
directionthroughenergy-efficient,sociallyacceptableandenvironmentallysoundwastewatermanagementsystems.The
reliabilityofthesesystems,aswellasotherkindsofwatertreatmentsystems,willincreaseastechnologyimprovesand
regulatoryframeworksadjusttotheuseofreclaimedwater.
Thesecyclicalsystemswouldbenefitfromfocusingonintegratingfeaturestoservemultiplepurposes.Forexample,a
greenroofwitharainwatercollectionfunctioncreatesacommunityspace,producesfood,providesacoolingamenityfor
thebuilding,mitigatesfloodriskandmakesfreshwateravailableforotheruses;naturalorman-madelakescreate
environmentalbufferstoaidinwatertreatment,createaestheticvalueandmayenhancebiodiversity;waterreuseaugments
thetotalwatersupply,decreasescontaminantsintheenvironmentandcreatesopportunitiesforenergygenerationandthe
recoveryofotherresources.Systemsshouldbeevaluatedintheframeworkofthewater–energynexustoensure
sustainabilityinbothaspects.
Potentialbarrierstoimplementationofcyclicalsystemsincludewaterqualityregulations,largeinvestmentsoftime,
moneyandmaterialsthatmaybenecessaryinreconfiguringanentiresystem,andsocietaloppositiontousingreclaimed
water.
8.5 IT-FOR-PURPOSE TREATMENT AND UTILISATION
Manyend-usesforwaterdonotnecessitatetheuseofpotablewater.Inmanycities,thequantityofwaterthatneedstobe
ofdrinkablequalitycomprisesnomorethanhalfoftheentirepotablewaterquantitysupplied,eveninhouseholds.Inwater
usedformunicipal,commercial,industrialandagriculturalpurposes,thispercentageismuchhigher.
Asmarterwaytoutilisewateristocategorisetherequirementsforwaterqualityintovariousgradesandthentocompare
therequirementswiththeintrinsicqualitiesofthewaterfromeachalternativesource.Thismethodisfit-for-purposesource
52 IWAALTERNATIVEWATERRESOURCESCLUSTER
selectionandfit-for-purposewatertreatment.Inthisway,wateruseefficiencycanbemaximised,andenergyconsumption
minimised.
Forexample,directuseofrainwaterafteronlysimplesedimentationprocessesispossible,asiscurrentlybeingpractised
inmanyAustralianhousesandcommunities.Tertiarywastewatertreatmentmaynotberequiredwhenthetreatedeffluentis
usedforagriculturalirrigation,becauseresidualsuspendedsolids,organics,nutrientsmaynothavenegativeimpactson
cropgrowth;theseconstituentsmayevenimprovecropyield.Seawatercanbedirectlyusedfortoiletflushing,withoutthe
needfordesalination,asispracticedinHongKong(section6.1).Finally,multi-stepreclaimedwaterusecanbemade
possibletoincreasetheefficiencyofwaterutilisationandiscurrentlybeingimplementedinMexico(section6.5).
Onepossiblechallengewhenimplementingfit-for-purposetreatmentisthepresenceofwaterqualityregulations,
whichmayrestricttheuseofwaterbelowacertainquality.Sincestandardsandregulationscanvarygreatlybylocation,
technologicalsolutionsforwaterreuseandtheirimplementationplansmustbetailoredtolocalguidelines.Implementers
maybenefitfromtakinglessonsfromsimilarjurisdictions,andfromcreatingsystemsthatcanbeamendedeasilywithsmall
changestotechnologyandregulatoryframeworks.Tocreatefewerproblemsinthefuture,regulationsmaybemadeflexible
enoughtorespondtorapidlyevolvingtechnologywhenpossible.Inanotherrespect,regulationsthatareinplacetoimprove
resourceefficiencymayactuallypromotetheuseoffit-for-purposetreatment,ratherthandeterit(UNWater,2015a).
8.6 DYNAMIC STRATEGIES
Animportantfactorwhencreatingwatermanagementstrategiesisthedynamicnatureofthewatersector.Newchallenges,
concernsandcontaminantsareconstantlyemerging,andthereforethetechnologymustbeconstantlyimprovedtokeepup
withpresentconditionsinsupplynetworks.Regulationsaffectingwatertreatmentandsupplyarealsopronetochanging,
resultingintheneedtoupdatetechnology.Therefore,long-term,holisticandflexiblestrategiesforimprovingwater
managementschemesaregenerallybetterthanone-timechanges.
Forexample,frequentlyneglectedinthedesignofinterventionsforwaterlossreductionisthedynamicnatureofwater
lossesandtheinteractionsofitscomponents.Manywater-lossreductionstrategiestendtofocusononepartofthesystem,
insteadofthenetworkasawhole.Efficiencyofawaternetworkatanymomentisthecombinedresultofitsnatural
deteriorationandthemeasuresthathavebeenputinplacetocombatthisdeterioration.Ifnothingisdone,therewillbe
anacceleratedproliferationofleaksandoccurrencesofdefectivewatermeters,aswellastheaccumulationofout-of-date
informationinthecustomerandnetworkdatabases.However,ifshort-termfixesareputinplaceandnotmaintained,
thesameresultcanoccur.Tosustainthegainsofwaterlossefficiency,thereshouldbeatendencytomoveawayfrom
short-terminterventionstowardsmulti-yearinvestmentplans,fundedthroughthewaterutilities’watertariffstructure,and
operationsshouldberefocusedtowardsthedesiredoutcome.
Thisgradual,dynamicapproachisalsopreferableforbuildingareputationandgainingpublictrust.Itisoftenmore
effectiveandsustainabletoworkslowlyandmakesteadyimprovementstobecomefirstinclass.Tobuildupagood
reputation,itisimportanttochooseandimplementsafeandreliabletechnologicalsolutions,andtoutilisegood
communication,committedandcapacitatedpersonnel,andsolidorganisationalprocedures.Utilitiesshouldtakecareand
ensurethesafetyofwaterwithmultiplebarriersandredundancies,asoneincidentcandestroyagoodreputationbuiltover
yearsofhardwork.
8.7 ENVIRONMENTAL PRIORITIES
Futuretechnologiesshouldbewellmanufactured,environmentallyfriendlyandenergyefficient.Soundengineeringpractices
shouldbemadeapriority,withtheaimtorespecttheenvironment.Thisincludesconsuminglessenergy–iftheyare
consumingconventionalenergyresources(gasoline,coal,naturalgas)–ordirectlyusingalternativeenergyresources(solar,
hydro,wind,biomass,etc.).Forexample,desalinationtechnologiescanbehighlyenergyconsuming;heatmustbeusedfor
waterevaporationinthermaldesalination,andelectricenergyisfundamentalinpumpingsystemsforRO.Harnessingthe
powerofrenewable,non-pollutingenergysourceswouldmakedesalinationamoresustainableresourceoption.Inthe
future,waterprofessionalswillbemoreawareofnewsustainabletechnologies.
Importantdecisionsregardingwaterandtheenvironmentshouldalsobemadewithlong-termsustainabilityinmind,
ratherthanshort-termgoalsorvestedinterestsofpoliticiansandbusinessleaders.Forexample,governmentsmaywishto
53 IWAALTERNATIVEWATERRESOURCESCLUSTER
strengthentheirtieswithparticularlyinfluentialindustriesbymakinghastydecisionsthatmaynotbeinthepublic’sbest
interestinthelong-run.Thismayincludegivingfinancialsupporttohighpollutingcompanies,orselectinginfeasibleprojects
asaresultoflobbyingthatwillbetooexpensivetomaintainorevenfinishinthefuture.Companiesmaymakedecisions
thatarenotsustainableinthelong-runbasedonshort-termprofits.
Notonlymustdecisionsbemadewiththeenvironmentandsustainableresourceuseinmind,butregulatorsmusthave
thewillingnessandthecapacitytoputinplacehighfinesfornon-compliancewithpoorpractices.Iffinesaretoolow,
industriesmayfinditcheapertopayratherthanaltertheirpractices.Finesandtaxesshouldforceashiftintheway
companiesviewpolluting.
54 IWAALTERNATIVEWATERRESOURCESCLUSTER
9 CONCLUSIONSOpportunitiesandneedsforimprovementarepresentinglobalwatermanagementstrategies.Theeffectsofclimatechange,
populationgrowth,over-consumptionandpollutionaretakingatollonourexistingresources,andweneedtoadapttheway
wethinkaboutandusewaterifwehopetocreateaneffective,efficient,reliableandresilientsupplyforthefuture.Allover
theworld,thesechangesarebeginningtooccur.Theresearch,trendsandcasestudiespresentedinthisCompendium
offerproofthatAWRareincreasinglybecomingincorporatedintowaterportfolios,anddisplaythebenefitsofadoptingsuch
practices.
Existingsolutionsrangeintheircosts,accessibilityandenergyefficiency.Mostdemand-managementstrategiestendto
berelativelylowcost,andsincetheyaimtoreducewaterproduction,theyactuallyreducestrainonwaterresources.RWH
isan–almost–energy-neutralandlow-costpracticethatcanbeusedalmostanywherethathassufficientprecipitation.
OtherAWRs,suchasreuseordesalination,aresaidtohavenearlimitlessquantities,butrequireenergyinproductionand
maybeexpensiveorproduceeffluentthatmustbedisposedof.Therefore,acomprehensiveunderstandingofthewater–
energynexusisneededinmakingdecisionsaboutAWRoptions,andintegrationofclean,renewableenergysourcesshould
beincorporatedintoprojectsasmuchaspossible.
Whicheverresourceoptionsareselectedforagivenscenario,itisessentialtotailorthemtothespecificlocationina
holistic,integratedfashion.Noonesolutioncanbegloballyapplicable,soitisuptowatermanagersandpoliticalleaders
–inconsultationwithrelevantstakeholders–toselectsolutionsthatsuittheregioninquestion,workwellinconjunction
andtakeintoaccountthesocial,economic,political/institutional,andenvironmentalfactorsofthearea.Doingsohasthe
potentialtocreateasafeandreliablewatersupply,whileminimisingunintendedconsequencesonenvironmentalsystems
andincreasingthesocio-economicwell-beingofthepopulation.
Ofcourse,watermanagementsectorsstillhavealongwaytogobeforeAWR-inclusiveportfolioscanbeglobally
implemented.Significantgapsexistinrelatedsectors,sobetterplatformsmustbecreatedonwhichexpertscancollaborate
toimprovenotonlytherobustnessofthetechnologybutalsoitsaccessibilityandsustainability.Enhancingthevisibilityof
successfulAWR-centredprojectsthroughconferences,mediaoutletsanddocumentssuchasthisCompendium,the
scientificcommunityandthegeneralpublicalikemaynotonlygrowtoacceptAWRpractices,butdemandthem.
55 AlternAtiveWAterresourcescluster
10 REFERENCES
7thWorldWaterForum.(2015).science&technologyProcess
WhitePaper.DaeguandGyeongbuk,republicofKorea.
AdvisorycommitteeonWaterissues.(nodate).Whatis
sustainability?unitedstatesDepartmentoftheinterior,united
statesGeologicalsurvey.http://acwi.gov/swrr/whatis-sustainability
-wide.pdf(accessed20August2015).
Adewumi,J.r.,ilemobade,A.A.,andvan,Z.J.e.(2010).treated
wastewaterreuseinsouthAfrica:overview,potentialand
challenges.Resources, Conservation & Recycling,55(2):
221–231.
Ahmed,W.,Hodgers,l.,sidhu,J.P.s.,andtoze,s.(2012).Fecal
indicatorsandzoonoticspathogensinhouseholddrinkingwater
tapsfedfromrainwatertanksinsoutheastQueensland,Australia.
Applied and Environmental Microbiology,78(1):219–226.
Al-Karaghouli,A.,andKazmerski,l.l.(2013).energyconsumption
andwaterproductioncostofconventionalandrenewable-energy-
powereddesalinationprocesses.Renewable and Sustainable
Energy Reviews,24:343–356.
Al-Zahrani,s.M.,choo,F.H.,tan,F.l.,andPrabu,M.(2012).
Portablesolardesalinationsystemusingmembranedistillation.
Water Practice & Technology,7(4):1–6.
Amin,M.t.,andHan,M.(2009).roof-harvestedrainwaterfor
potablepurposes:applicationofsolarcollectordisinfection
(soco-Dis).Water Research,43(20):5225–5235.
Amin,M.t.,andHan,M.(2011).improvementofsolarbased
rainwaterdisinfectionbyusinglemonandvinegarascatalysts.
Desalination,276(1–3):416–423.
Anderson,H.r.,lundsbye,M.,Wedel,H.v.,eriksson,e.,and
ledin,A.(2007).estrogenicpersonalcareproductsinagreywater
reusesystem.Water Science & Technology,56(12):45–49.
Balnave,J.,andAdeyeye,K.(2013).Acomparativestudyof
attitudesandpreferencesforwaterefficiencyinhomes.Journal of
Water Supply: Research and Technology,62(8):515–524.
Barringer,J.(2014).urbandomesticandcommercialwaterreuse
inPuneanditsinfluenceonthepresentwatercrisis.Water Quality,
Exposure and Health,6:35–38.
Bashitialshaaer,r.,andPersson,K.M.(2011).Ajointpowerand
desalinationplantforsinaiandGazastrip.Water Science &
Technology: Water Supply,11(5):586–595.
Baten,r.,andstummeyer,K.(2013).Howsustainablecan
desalinationbe?Desalination and Water Treatment,51:44–52.
Beal,c.,stewart,r.A.,spinks,A.,andFielding,K.(2011).using
smartmeterstoidentifysocialandtechnologicalimpactson
residentialwaterconsumption.Water Science & Technology: Water
Supply,11(5):527–533.
Bele,c.,Kumar,Y.,Walker,t.,Poussade,Y.,andZavlanos,v.
(2010).operatingboundariesoffull-scaleadvancedwaterreuse
treatmentplants:manylessonslearnedfrompilotplantexperience.
Water Science & Technology,62(7):1560–1566.
Belmeziti,A.,coutard,o.,anddeGouvello,B.(2014).Howmuch
drinkingwatercanbesavedbyusingrainwaterharvestingona
largeurbanarea?ApplicationtoParisagglomeration.Water
Science & Technology,70(11):1782–1788.
Bhaduri,A.,andManna,u.(2014).impactsofwatersupply
uncertaintyandstorageonefficientirrigationtechnologyadoption.
Natural Resource Modeling,27(1):1–24.
Biswas,r.,Khare,D.,andshankar,r.(2009).Waterdemand
managementforanurbanarea:thecasestudyofDwarka,a
sub-cityofDelhi.Water Utility Management International,4(2):
10–17.
Biswas,s.K.,rahman,M.,rahman,Y.A.,andrahman,M.(2012).
Applicabilityofdomesticgreywaterreuseforalleviationofwater
crisisinDhakacity.Journal of Water Reuse and Desalination,2
(4):239–246.
Blanksby,J.(2006).Water Conservation and Sewerage Systems.
WaterDemandManagement,iWAPublishing,london,uK:
107–128.
Bluefieldresearch.(2015).californiaWaterPortfolioPoisedfor
Makeover.researchnote.
Bosman,D.(2014).large-scaledesalination:whatcanwelearn
fromAustralia?Water Wheel,13(3):22–25.
Brandes,o.M.,renzetti,s.,stinchcombe,K.(2010).Worth Every
Penny: A Primer of Conservation-Oriented Water Pricing.
universityofvictoria.
Brown,r.(2013).thetruecostofdesalination.Planning,79:9.
Brown,r.r.,andDavies,P.(2007).understandingcommunity
receptivitytowaterre-use:Ku-ring-gaicouncilcasestudy.Water
Science & Technology,55(4):283–290.
56AlternAtiveWAterresourcescluster
cornejo,P.K.,santana,M.v.e.,Hokanson,D.r.,Mihelcic,J.r.,
andZhang,Q.(2014).carbonfootprintofwaterreuseand
desalination:areviewofgreenhousegasemissionsandestimation
tools.Journal of Water Reuse and Desalination,4(4):238–252.
Daigger,G.t.,Hodgkinson,A.,Aquilina,s.,andBurrowes,P.
(2013).creationofasustainablewaterresourcethrough
reclamationofmunicipalandindustrialwastewaterintheGippsland
WaterFactory.Journal of Water Reuse and Desalination,3(1):
1–15.
David,H.s.(2012).Water Crisis in Africa.elliottschoolof
internationalAffairs,GeorgeWashingtonuniversity.
DeBusk,K.M.,Hunt,W.F.,andWright,J.D.(2013).characterizing
rainwaterharvestingperformanceanddemonstratingstormwater
managementbenefitsinthehumidsoutheastusA. JAWRA Journal
of the American Water Resources Association,49(6):
1398–1411.
deGouvello,B.,nguyen-Deroche,n.,lucas,F.,andGromaire,
M.-c.(2013).Amethodologicalstrategytoanalyzeandimprovethe
Frenchrainwaterharvestingregulationinrelationtoquality.Water
Science & Technology,67(5):1043–1050.
Delgado,D.M.(2008).Infrastructure Leakage Index (ILI) as a
Regulatory and Provider Tool.GraduateDissertation,universityof
Arizona.
Deng,X.,shan,l.,Zhang,H.,andturner,n.c.(2006).improving
agriculturalwateruseefficiencyinaridandsemiaridareasofchina.
Agricultural Water Management,80:23–40.
Dixon,A.M.,andMcManus,M.(2006).An Introduction to Life
Cycle and Rebound Effects in Water Systems,pp.130–140.
WaterDemandManagement,iWAPublishing,london,uK.
Dobrowsky,P.H.,DeKwaadsteniet,M.,cloete,t.e.,andKhan,W.
(2014).Distributionofindigenousbacterialpathogensandpotential
pathogensassociatedwithroof-harvestedrainwater.Applied and
Environmental Microbiology,80(7):2307–2316.
Domènech,laia.(2011).rethinkingwatermanagement:from
centralisedtodecentralisedwatersupplyandsanitationmodels.
Documents d’Anàlisi Geogràfica,57(2):293–310.
Drewes,J.e.,andKhan,s.J.(2015).contemporarydesign,
operation,andmonitoringofpotablereusesystems.Journal of
Water Reuse and Desalination,5(1):1–7.
elsaliby,i.,okour,Y.,shon,H.K.,Kandasamy,J.,andKim,i.s.
(2009).DesalinationplantsinAustralia,reviewandfacts.
Desalination,247(1):1–14.
Buckle,J.s.(2004).Waterdemandmanagement–philosophyor
implementation?Water Science & Technology: Water Supply,4
(3):25–32.
Butler,D.,andMemon,F.(2006).Water Consumption Trends and
Demand Forecasting Techniques,pp.1–25.WaterDemand
Management,iWAPublishing,london,uK.
carr,G.,nortcliff,s.,andPotter,r.B.(2011).Waterreusefor
irrigationinJordan:plantbeneficialnutrients,farmers’awareness
andmanagementstrategies.Water Science & Technology,63(1):
10–15.
californiaDepartmentofWaterresources.(2015).reviewof
irWMPlanningandimplementationincalifornia.http://
www.water.ca.gov/irwm/stratplan/documents/review_of_irWM_
Planning_and_implementation_in_california.pdf(accessed18
August2015).
chanan,A.,vigneswaran,s.,andKandasamy,J.(2010).valuing
stormwater,rainwaterandwastewaterinthesoftpathforwater
management:Australiancasestudies.Water Science &
Technology,62(12):2854–2861.
chiang,v.c.,Kao,M.H.,andliu,J.c.(2013).Assessmentof
rainwaterharvestingsystemsatauniversityintaipei.Water
Science & Technology,67(3):564–571.
cityofGuelph.(2009).Waterconservationandefficiencystrategy
update.http://guelph.ca/wp-content/uploads/Wcesupdate_
Finalreport.pdf(accessed9July2015).
cityofGuelph.(2013).GuelphWaterconservationProgress
report.http://guelph.ca/living/environment/water/water-
conservation/guelph-water-conservation-progress-report/(accessed
25June2015).
charteredinstitutionofWaterandenvironmentalManagement.
(2012).industrialwaterreuse.http://www.ciwem.org/policy-and-
international/current-topics/water-management/water-reuse/
industrial-water-reuse.aspx(accessed23June2015).
conway,B.D.(2014).MonitoringlandsubsidenceinArizonaDue
toexcessiveGroundwaterWithdrawalusinginterferometric
syntheticApertureradar(insAr)Data. In AGU Fall Meeting
Abstracts,1:l08.
coombes,P.J.,Dunstan,H.,spinks,A.,evans,c.,MartinA.,and
Harrison,t.(2006).insightfromadecadeofresearchintothe
qualityofrainwatersuppliescollectedfromroofs.6th International
Workshop on Rainwater Harvesting and Management,Seoul,
South Korea. August24,2006.
57 AlternAtiveWAterresourcescluster
Ghyselbrecht,K.,Huygebaert,M.,vanderBruggen,B.,Ballet,r.,
Meesschaert,B.,andPinoy,l.(2013).Desalinationofanindustrial
salinewaterwithconventionalandbipolarmembrane
electrodialysis.Desalination,318:9–18.
GippslandWater.(n.D.).DraftWaterPlan3Proposal:Gippsland
WaterAchievements20082012.http://www.gippswater.com.au/
Portals/0/neWs/Fact%20sheet%2015%20–%20GW%20
Achievements%20–%204%20pages.pdf(accessed16June2015).
GlobalFootprintnetwork.(2015).FootprintBasics–overview.
http://www.footprintnetwork.org/en/index.php/GFn/page/footprint_
basics_overview/(accessed20August2015).
Godfrey,s.,labhasetwar,P.,Wate,s.,andJimenez,B.(2010).
safegreywaterreusetoaugmentwatersupplyandprovide
sanitationinsemi-aridareasofruralindia.Water Science &
Technology,62(6):1296–1303.
Grant,n.(2006).Water Conservation Products. Water Demand
Management,iWAPublishing,london,uK:82–106.
Greatlakescommission.(2015).HighreturnsonBetterWater
ManagementforthecityofGuelph.http://glc.org/files/
Greaterlakes-Guelph-Factsheet-20150826.pdf(accessed9July
2015).
GlobalDevelopmentresearchcentre.(nodate)rainwater
Harvestingandutilisation.http://www.gdrc.org/uem/water/
rainwater/rainwaterguide.pdf(accessed30April2015).
Globalreportinginitiative.(2013).G4sustainabilityreporting
Guidelines:reportingPrinciplesandstandardDisclosures.https://
www.globalreporting.org/resourcelibrary/GriG4–Part1–reporting-
Principles-and-standard-Disclosures.pdf(accessed21August
2015).
GlobalWaterPartnership.(2012).WhatisiWrM?http://
www.gwp.org/en/the-challenge/What-is-iWrM/(accessed20
August2015).
Gude,v.G.,nirmalakhandan,n.,andDeng,s.(2010).renewable
andsustainableapproachesfordesalination.Renewable and
Sustainable Energy Reviews,14(9):2641–2654.
Haering,K.c.,evanylo,G.K.,Benham,B.,andGoatley,M.(2009).
Water Reuse: Using Reclaimed Water for Irrigation.virginia
cooperativeextension,Publication452–014.
Han,M.Y.(2006).Proactivemulti-purposerainwatermanagementin
Korea.Proceedings of the 2nd International Rainwater Harvesting
Workshop,IWA 5th World Water Congress and Exhibition,
september11pp.,london,55–62.
europeancommission.(2011).newmethodforestimatingthe
energyconsumptionofrainwater.http://ec.europa.eu/environment/
integration/research/newsalert/pdf/265na5_en.pdf(accessedJune
222015).
europeanenvironmentAgency.(2001).Sustainable Water Use in
Europe (Part II): Demand Management.europeanenvironment
Agency,environmentalissuereportno.19.
europeanenvironmentAgency.(2013).Water:chargingfullcost
canencouragemoreefficientuse.http://www.eea.europa.eu/
highlights/water-charging-full-cost-can(accessed30April2015).
FoodandAgricultureAssociationoftheunitednations.(2013).
WaterneWs:climatechange&Water.http://www.fao.org/nr/
water/news/clim-change.html(accessed4June2015).
Fan,l.,Wang,F.,liu,G.,Yang,X.,andQin,W.(2014).Public
perceptionofwaterconsumptionanditseffectsonwater
conservationbehaviour.Water,6:1771–1784.
Farley,M.,andtrow,s.(2003).Losses in Water Distribution
Networks: A Practitioner’s Guide to Assessment, Monitoring and
Control.iWAPublishing,london.
Fewkes,A.(2006).The Technology, Design and Utility of
Rainwater Catchment Systems. Water Demand Management,iWA
Publishing,london,uK:27–57.
Fielding,K.s.,spinks,A.,russell,s.,Mccrea,r.,stewart,r.,and
Gardner,J.(2013).Anexperimentaltestofvoluntarystrategiesto
promoteurbanwaterdemandmanagement.Journal of
Environmental Management,114:343–51.
Fletcher,t.D.,Mitchell,v.G.,Deletic,A.,ladson,t.r.,andséven,
A.(2007).isstormwaterharvestingbeneficialtourbanwaterway
environmentalflows?Water Science & Technology,55(4):
265–272.
Fraserinstitute.(2010).theManagementofWaterservicesin
Montreal.https://www.fraserinstitute.org/uploadedFiles/fraser-ca/
content/Files/management-of-water-services-in-montreal.pdf
(accessed29May2015).
Gavrila,c.,teodorescu,n.,andGruia,i.(2013).Bayesian
modellingforwaterlossmanagementdecisions.Water Science &
Technology: Water Supply,13(4):883–888.
Ghaffour,n.,Missimer,t.M.,andAmy,G.l.(2013).combined
desalination,waterreuse,andaquiferstorageandrecoverytomeet
watersupplydemandsintheGcc/MenAregion.Desalination and
Water Treatment,51:38–43.
58AlternAtiveWAterresourcescluster
Karim,M.r.(2010a).Assessmentofrainwaterharvestingfor
drinkingwatersupplyinBangladesh.Water Science & Technology:
Water Supply,10(2):243–249.
Karim,M.r.(2010b).Microbialcontaminationandassociated
healthburdenofrainwaterharvestinginBangladesh. Water
Science & Technology,61(8):2129–2135.
Kayaga,s.,smout,i.,andAl-Maskati,H.(2007).Waterdemand
management–shiftingurbanwatermanagementtowards
sustainability.Water, Science & Technology: Water Supply,7(4):
49–56.
Kempton,r.,Maccioni,D.,Mrayed,s.M.,andleslie,G.(2010).
thermodynamicefficienciesandGHGemissionsofalternative
desalinationprocesses.Water Science & Technology: Water
Supply,10(3):416–427.
Kidson,r.,Haddad,B.,andZheng,H.(2006)improvingWater
supplyreliabilitythroughPortfolioManagement:casestudyfrom
southerncalifornia.http://www.kysq.org/docs/Kidson.pdf
(accessed15June2015).
Kim,e-s.,Dong,s.,liu,Y.,andel-Din,M.G.(2013).Desalination
ofoilsandsprocessaffectedwaterandbasaldepressurization
waterinFortMcMurray,Alberta,canada:applicationof
electrodialysis.Water Science & Technology,68(12):2668–2675.
Kim,M.,andHan,M.(2013).roleofbiofilmsinimprovingmicrobial
qualityinrainwatertanks.Desalination and Water Treatment:1–6.
Doi:10.1080/19443994.2013.867817.
Kim,M.,andHan,M.(2014)characteristicsofbiofilmdevelopment
inanoperatingrainwaterstoragetank.Environmental Earth
Sciences,24.Doi:10.1007/s12665–014–3067–2.
Kim,Y.,Han,M.,Kabubi,J.,sohn,H-G.,andnguyen,D-c.(in
press).community-basedrainwaterharvesting(cB-rWH)for
drinkingwatersupplyindevelopingcountrieswithspecialfocuson
AfricaandAsia:lessonslearnedfromcasestudiesinAfricaand
Asia.Water Science and Technology: Water Supply.Doi10.2166/
ws.2016.012
Kim,M.,ravault,J.,Han,M.,andKim,K.(2012).impactofthe
surfacecharacteristicsofrainwatertankmaterialonbiofilm
development.Water Science & Technology,66:1225–1230.
Kingdom,B.,liemberger,r.,andMarin,P.(2006).thechallenge
ofreducingnonrevenueWater(nrW)inDevelopingcountries.
HowthePrivatesectorcanHelp:AlookatPerformance-Based
servicecontracting.The World Bank Group.http://siteresources
.worldbank.org/intWss/resources/Wss8fin4.pdf(accessed3
August2015).
Han,M.,andKi,J.(2010).establishmentofsustainablewater
supplysysteminsmallislandsthroughrainwaterharvesting(rWH):
casestudyofGuja-do.Water Science & Technology,62(1):
148–153.
Han,M.Y.,andMun,J.s.(2011).operationaldataofstarcity
rainwaterharvestingsystemanditsroleasaclimatechange
adaptationandasocialinfluence.Water Science & Technology,
63(12):2796–2801.
Han,M.andMun,J.(2007)Particlebehaviorconsiderationto
maximizethesettlingcapacityofrainwaterstoragetanks.Water
Science & Technology56(11):73–79.
Harper,B.(2014).sustainableDesalination-AMultipurposeFacility
DevelopedtoAlleviateWatercrisessufferedbysmallisland
nationsDuetoGlobalclimatechange.http://scholarworks
.boisestate.edu/eng_14/20/(accessed2June2015).
Henmi,M.,Fusaoka,Y.,tomioka,H.,andKurihara,M.(2010).High
performanceromembranesfordesalinationandwastewater
reclamationandtheiroperationresults.Water Science &
Technology – WST,62(9):2134–2140.
Hu,Y.,Wang,X.c.,Zhang,Y.,li,Y.,chen,H.,andJin,P.(2013).
characteristicsofanA2o–MBrsystemforreclaimedwater
productionunderconstantfluxatlowtMP.Journal of Membrane
Science,431:156–162.
internationalWaterAssociation.(2014).International Statistics for
Water Services.PDFBrochure.
Kalavrouziotis,i.K.,Kokkinos,P.,oron,G.,Fatone,F.,Bolzonella,
D.,vatyliotou,M.,Fatta-Kassinos,D.,andvarnavas,s.P.(2015).
currentstatusinwastewatertreatment,reuseandresearchinsome
mediterraneancountries.Desalination and Water Treatment,53(8):
2015–2030.
Kaushik,r.,Balasubramanian,r.,anddelacruz,A.A.(2012).
influenceofairqualityonthecompositionofmicrobialpathogens
infreshrainwater.Applied and Environmental Microbiology,78(8):
2813–2818.
Karadirek,i.e.,Kara,s.,Yilmaz,G.,Muhammetoglu,A.,and
Muhammetoglu,H.(2012).implementationofhydraulicmodelling
forwater-lossreductionthroughpressuremanagement. Water
Resources Management,26(9):2555–2568.
Karagiannis,i.c.,andsoldatos,P.G.(2008).Waterdesalination
costliterature:reviewandassessment.Desalination Amsterdam,
223:448–456.
59AlternAtiveWAterresourcescluster
lim,s.-r.,andPark,J.M.(2011).Positiveandnegativeeffectsof
excessivewaterreusetobeconsideredinwaternetworksynthesis.
Korean Journal of Chemical Engineering,28(2):511–518.
listowski,A.,ngo,H.H.,Guo,W.s.,andvigneswaran.(2011).A
novelintegratedassessmentmethodologyofurbanwaterreuse.
Water Science & Technology,64(8):1642–1651.
liu,l.,Zeng,s.,Dong,X.,andchen,J.(2013a).Designand
assessmentofurbandrainageandwaterreusesystemsforthe
reconstructionofformerlyindustrialareas:acaseinBeijing.Water
Science & Technology,67(1):55–62.
loureiro,D.,Alegre,H.,coelho,s.t.,Martins,A.,andMamade,A.
(2014).Anewapproachtoimprovewaterlosscontrolusingsmart
meteringdata.Water Science & Technology: Water Supply,14(4):
618–625.
lucas,s.A.,coombes,P.J.,andsharma,A.K.(2010).theimpact
ofdiurnalwaterusepatterns,demandmanagementandrainwater
tanksonwatersupplynetworkdesign.Water, Science &
Technology: Water Supply,10(1):69–80.
liu,H.,Yin,Y.,Piao,s.,Zhao,F.,engels,M.,andciais,P.(2013b).
Disappearinglakesinsemiaridnorthernchina:driversand
environmentalimpact.Environmental Science & Technology,47
(21):12107–14.
Macedonio,F.,Drioli,e.,Gusev,A.A.,Bardow,A.,semiat,r.and
Kurihara,M.(2012).efficienttechnologiesforworldwideclean
watersupply.Chemical Engineering & Processing: Process
Intensification,51:2–17.
Macharg,J.P.(2011).theevolutionofsWroenergyrecovery
systems.Energy Recovery Systems,USA. http://ocean-pacific
-tec.com/imagenes/news/18%20D&Wr%2011–01%20final
%20article.pdf(accessed1september2015).
Maraver,D.,uche,J.,androyo,J.(2012).Assessmentofhigh
temperatureorganicrankinecycleengineforpolygenerationwith
MeDdesalination:Apreliminaryapproach.Energy Conversion and
Management,53(1):108–117.
Massarutto,A.(2007).Waterpricingandfull-costrecoveryofwater
services:economicincentiveorinstrumentofpublicfinance?Water
Policy,9(6):591–613.
McArdle,P.,Gleeson,J.,Hammond,t.,Heslop,e.,Holden,r.,and
Kuczera,G.(2010).centralisedurbanstormwaterharvestingfor
potablereuse.Water Science & Technology,63(1):16–24.
Mccann,W.(2008).seoul’sstarcity:arainwaterharvesting
benchmarkforKorea.Water21:17–18.
lahnsteiner,J.,andlempert,G.(2007).Watermanagementin
Windhoek,namibia.Water Science & Technology,55(1–2):
441–448.
lattemann,s.,andHöpner,t.(2008).environmentalimpactand
impactassessmentofseawaterdesalination.Desalination,220(1):
1–15.
law,i.B.,Menge,J.,andcunliffe,D.(2015).validationofthe
GoreangabreclamationPlantinWindhoek,namibiaagainstthe
2008AustralianGuidelinesforWaterrecycling.Journal of Water
Reuse and Desalination,5(1):64–71.
lazarova,v.,equihua,l.,androjas,A.(2014).sustainablewater
managementwithmulti-qualityrecycledwaterproduction:the
exampleofsanluisPotosiinMexico.Journal of Water Reuse and
Desalination,4(1):18–24.
lazarova,v.,sturny,v.,andsang,G.t.(2012).theroleofthe
communityengagementtowardsthesuccessofwaterreusein
isolatedislandsandtouristareas.Journal of Water Reuse and
Desalination,2(1):1–12.
lee,J.Y.,Bak,G.P.andHan,M.Y.(2012).Qualityofroof-harvested
rainwater–comparisonofdifferentroofingmaterials.
Environmental Pollution162:422–429.
lee,H.,andYuen,Z.(2015).HongKong’sHAtsschemetargets
waterqualityprogressforvictoriaHarbour.Water21,17(2):
21–24.
leung,r.W.K.,li,D.c.H.,Yu,W.K.,chui,H.K.,lee,t.o.,van
loosdrecht,M.c.M.,andchen,G.H.(2012).integrationof
seawaterandgreywaterreusetomaximizealternativewater
resourceforcoastalareas:thecaseoftheHongKonginternational
Airport.Water Science & Technology,65(3):410–417.
leverenz,H.l.,tchobanoglous,G.,andAsano,t.(2011).Direct
potablereuse:afutureimperative.Journal of Water Reuse and
Desalination,1(1):2–10.
li,X-M.,Zhao,B.,Wang,Z.,Xie,M.,song,J.,nghiem,l.D.,He,t.,
Yang,c.,li,c.,andchen,G.(2014).Waterreclamationfromshale
gasdrillingflow-backfluidusinganovelforwardosmosis-vacuum
membranedistillationhybridsystem.Water Science & Technology,
69(5):1036–1044.
liao,Z.l.,He,Y.,Huang,F.,Wang,s.,andli,H.Z.(2013).
AnalysisonliDforhighlyurbanizedareas’waterloggingcontrol:
demonstratedontheexampleofcaohejinginshanghai.Water
Science & Technology,68(12):2559–2567.
liemberger,r.(2009).Waterlossandremediationinsouthand
southeastAsia.Water Practice & Technology,4(4):1–15.
60AlternAtiveWAterresourcescluster
nguyen,D.c.,andHan,M.Y.(2014).Designofdualwatersupply
systemusingrainwaterandgroundwateratarseniccontaminated
areainvietnam.Journal of Water Supply: Research and
Technology – AQUA,63(7):578–585.
niazi,A.,Prasher,s.,Adamowski,J.,andGleeson,t.(2014).A
systemdynamicsmodeltoconservearidregionwaterresources
throughaquiferstorageandrecoveryinconjunctionwithadam.
Water,6(8):2300–2321.
olsson,G.(2012).Water and Energy: Threats and Opportunities.
iWAPublishing,london.
organisationforeconomiccooperationandDevelopment.(2010).
Alternative Ways of Providing Water: Emerging Options and Their
Policy Implications.Advancecopyforthe5thWorldWaterForum.
Park,G.l.,schäfer,A.i.,andrichards,B.s.(2012).theeffectof
intermittentoperationonawind-poweredmembranesystemfor
brackishwaterdesalination.Water Science & Technology,65(5):
867–874.
Paydar,Z.,andQureshi,M.e.(2012).irrigationwatermanagement
inuncertainconditionsApplicationofModernPortfoliotheory.
Agricultural Water Management,115,47–54.
Perez-Pedini,c.,limbrunner,J.F.,andvogel,r.M.(2005).optimal
locationofinfiltration-basedbestmanagementpracticesforstorm
watermanagement.Journal of Water Resources Planning and
Management,131(6):441–448.
Pimentel,D.,Berger,B.,Filiberto,D.,newton,M.,Wolfe,B.,
Karabinakis,e.,clark,s.,Poon,e.,Abbett,e.,andnandagopal,s.
(2004).Waterresources:agriculturalandenvironmentalissues.
BioScience,54(10):909–918.
Price,J.i.,chermak,J.M.,andFelardo,J.(2014).low-flow
appliancesandhouseholdwaterdemand:anevaluationof
demand-sidemanagementpolicyinAlbuquerque,newMexico.
Journal of Environmental Management,133:37–44.
radcliffe,J.c.(2015).Australia’sexperiencefrom25yearsof
waterrecycling.FirstAsiansymposiumonWaterreuse,tsinghua
university.
ramezanianpour,M.,andsivakumar,M.(2015).energyevaluation
andtreatmentefficiencyofvacuummembranedistillationfor
brackishwaterdesalination.Journal of Water Reuse and
Desalination,5(2):119–131.
raucher,r.s.,andtchobanoglous,G.(2014).theopportunities
andeconomicsofDirectPotablereuse.WateReuse Research.
Web.
McKay,s.F.,andKing,A.J.(2006).Potentialecologicaleffectsof
waterextractioninsmall,unregulatedstreams.River Research and
Applications,22(9):1023–1037.
Mekonnen,M.M.,Gerbens-leenes,P.W.,andHoekstra,A.Y.
(2015).theconsumptivewaterfootprintofelectricityandheat:a
globalassessment.Environmental Science: Water Research &
Technology,1(3):255–396.
Mendez,e.(2012).sustainabledesalination:Membranedistillation
deliversgreenercleanwater.Filtration and Separation,49(5):
26–28.
Mogheir,Y.,Ahmad,A.F.,Abuhabib,A.A.,andMohammad,A.W.
(2013).large-scalebrackishwaterdesalinationplantsinGaza
strip:assessmentsandimprovements.Journal of Water Reuse and
Desalination,3(3):315–324.
Molinos-senante,M.(2014).Waterratetomanageresidential
waterdemandwithseasonality:peak-loadpricingandincreasing
blockratesapproach.Water Policy,16(5):930–944.
Mollenkopf,tom.(2014)Watersolutionsforavariableclimate:
examplesfromAustralia.Presentation,Nanning, China.
Morrison,J.,Morikawa,M.,Murphy,M.,andschulte,P.(2009).
Waterscarcity&climatechange.ceresandPacificinstitute.
www.pacinst.org/reports/business_water_climate/full_report.pdf
(accessed17June2015).
Mun,J.,andHan,M.(2012).Designandoperationalparametersof
arooftoprainwaterharvestingsystem:definition,sensitivityand
verification.Journal of Environmental Management,93(1):
147–153.
Mun,J.Y.,Kim,D.G.,Kang,B.J.,Park,Y.H.,andAhn,H.W.
(2008).Waterlossmanagement:acasestudyinKorea.Water
Practice & Technology,3(2):1–7.
Mwamila,t.B.,Han,M.Y.,andndomba,P.M.(2015).tackling
rainwatershortagesduringdryseasonsusingasocio-technical
operationalstrategy.Water Practice & Technology: Water Supply,
15(5)974–980.
nationalWatercommission.(2014).nationalPerformancereport
2012–13:urbanWaterutilities.Australian Government.https://
www.wsaa.asn.au/WsAAPublications/Documents/2012–13%20
national%20Performance%20report%20Part%20A.pdf(accessed
26June2015).
ng,K.c.,thu,K.,Kim,Y.,chakraborty,A.,Amy,G.,andnew
DirectionsinDesalination.(2013).Adsorptiondesalination:an
emerginglow-costthermaldesalinationmethod.Desalination,308:
161–179.
61 AlternAtiveWAterresourcescluster
stern,n.(2007).The Economics of Climate Change: The Stern
Review.cambridgeuniversityPress.
stillwell,A.s.,twomey,K.M.,osborne,r.,Greene,D.M.,
Pedersen,D.W.,andWebber,M.e.(2011).Anintegratedenergy,
carbon,water,andeconomicanalysisofreclaimedwaterusein
urbansettings:acasestudyofAustin,texas.Journal of Water
Reuse and Desalination,1(4):208–223.
stump,B.,McBroom,M.,andDarville,r.(2012).Demographics,
practicesandwaterqualityfromdomesticpotablerainwater
harvestingsystems.Journal of Water Supply: Research and
Technology,61(5):261–271.
tambo,n.,nakamura,M.,andWang,X.(2012).thefractal
lentic-loticbasincomplexasaconceptualbasisforfutureurban
watersystems.Journal of Water Sustainability,2(2):105–120.
teatini,P.,Ferronato,M.,Gambolati,G.,andGonella,M.(2006).
Groundwaterpumpingandlandsubsidenceintheemilia-romagna
coastland,italy:modelingthepastoccurrenceandthe
futuretrend.Water Resources Research,42(1).Doi:
10.1029/2005Wr004242.
thoren,r.i.,Atwater,J.,andBerube,P.(2012).Amodelfor
analyzingwaterreuseandresourcerecoverypotentialinurban
areas.Canadian Journal of Civil Engineering,39(11):
1202–1209.
tischbein,B.,Manschadi,A.M.,conrad,c.,Hornidge,A.K.,
Bhaduri,A.,ulHassan,M.,lamers,J.P.A.,Awan,u.K.,andvlek,
P.l.G.(2013).Adaptingtowaterscarcity:constraintsand
opportunitiesforimprovingirrigationmanagementinKhorezm,
uzbekistan.Water, Science & Technology: Water Supply,13(2):
337–348.
travis,M.J.,Wiel-shafran,A.,Weisbrod,n.,Adar,e.,andGross,A.
(2010).Greywaterreuseforirrigation:effectonsoilproperties.The
Science of the Total Environment,408(12):2501–2508.
trow,s.,andFarley,M.(2004).Developingastrategyforleakage
managementinwaterdistributionsystems.Water, Science &
Technology: Water Supply,4(3):149–168.
trow,s.,andFarley,M.(2006).Developing a Strategy for
Managing Losses in Water Distribution Systems,pp.141–179
WaterDemandManagement,iWAPublishing,london,uK.
turek,M.(2003).costeffectiveelectrodialyticseawater
desalination.Desalination,153:371–376.
unitednations.(2014).theHumanrighttoWater.http://
www.un.org/waterforlifedecade/human_right_to_water.shtml
(accessed20August2015).
regionalDistrictofnanaimo.(2012).Rainwater Harvesting Best
Practices Guidebook.Britishcolumbia,canada.
renaud,e.,clauzier,M.,sandraz,c.,Pillot,J.,andGilbert,D.
(2014).introducingpressureandnumberofconnectionsintowater
lossindicatorsforFrenchdrinkingwatersupplynetworks.Water
Science & Technology: Water Supply,14(6):1105–1111.
rensburg,l.D.,Botha,J.J.,Anderson,J.J.,andHensley,M.
(2012).thenatureandfunctionofthein-fieldrainwaterharvesting
systemtoimproveagronomicsustainability.Irrigation and Drainage,
61:34–40.
rietveld,l.c.,norton-Brandão,D.,shang,r.,vanAgtmaal,J.,and
vanlier,J.B.(2011).Possibilitiesforreuseoftreateddomestic
wastewaterinthenetherlands.Water Science & Technology,64
(7):1540–1546.
roux,A.(2013).WindhoekWaterreuseconference2013:
report.http://greencape.co.za/assets/sector-files/water/
iWA-Water-reuse-conference-Windhoek-2013.pdf(accessed
31August2015).
saharaForestProject(nodate).Projects:Qatar.http://
saharaforestproject.com/projects/qatar.html(accessed
9september2015).
schnoor,J.l.(2011).Water–energynexus.Environmental Science
& Technology,45(12):5065–5065.
schouten,M.,andHalim,r.D.(2010).resolvingstrategy
paradoxesofwaterlossreduction:asynthesisinJakarta.
Resources, Conservation and Recycling,54(12):1322–1330.
schreiner,G.o.,vanBallegooyen,r.c.,andosman,W.(2014).
seawaterdesalinationasanoptiontoalleviatewaterscarcityin
southAfrica:theneedforastrategicapproachtoplanningand
environmentaldecision-making.Journal of Water Reuse and
Desalination,4(4):287–293.
sharma,s.K.,andvairavamoorthy,K.(2009).urbanwaterdemand
management:prospectsandchallengesforthedeveloping
countries.Water and Environment Journal,23(3):210–218.
shin,e.,Park,H.,ryu,t.,Kim,J.,andYum,K.t.(2005).improving
operationalefficiencybyinterconnectingregionalwaterdistribution
systems.Water Supply,5(3–4):137–143.
steffen,J.,Jensen,M.,Pomeroy,c.A.,andBurian,s.J.(2013).
WatersupplyandstormwaterManagementBenefitsofresidential
rainwaterHarvestinginu.s.cities.Journal of the American Water
Resources Association,49(4):810–824.
62 AlternAtiveWAterresourcescluster
vohland,K.,andBarry,B.(2009).Areviewofinsiturainwater
harvesting(rWH)practicesmodifyinglandscapefunctionsin
Africandrylands.Agriculture, Ecosystems & Environment,131(3):
119–127.
vonMedeazza,G.M.(2004).Waterdesalinationasalong-term
sustainablesolutiontoalleviateglobalfreshwaterscarcity?A
north–southapproach.Desalination,169(3):287–301.
Waldron,t.(2001).Managing and Reducing Losses from Water
Distribution Systems: Manual 1 – Introduction.Queensland
environmentalProtectionAgency&WideBayWater.
Waldron,t.(2007).reducingwaterlossthroughautomaticmeter
reading.Water21,9(6):22–23.
Wang,W.,Zeng,W.,Yao,B.,andWei,J.(2014).Asimulation
impactevaluationofsocialeconomicdevelopmentonwater
resourceuse.Journal of Water Reuse and Desalination,4 (3):
137–153.
Wang,X.c.,Zhang,c.,Ma,X.,andluo,l.(2015).Water Cycle
Management: A New Paradigm of Wastewater Reuse and Safety
Control.springerBriefsinWaterscienceandtechnology.
Warner,W.s.(2006).Undertanding Greywater Treatment,
pp.62–79WaterDemandManagement,iWAPublishing,
london,uK.
WatereuseAssociation.(2012).seawaterDesalinationcosts.
https://www.watereuse.org/sites/default/files/u8/Watereuse_Desal
_cost_White_Paper.pdf(accessed18June2015).
WatereuseFoundation.(2004).BestPracticesforDeveloping
indirectPotablereuseProjects.http://www.waterboards.ca.gov/
water_issues/programs/grants_loans/water_recycling/research/
01_004_01.pdf(accessed18May2015).
WaterresearchFoundation.(2015).casestudy:colorado
springsutilities.http://www.waterrf.org/resources/lists/
Publiccasestudieslist/Attachments/28/colorado%20springs
_case%20study.pdf(accessed24June2015).
Watkins,D.W.,Mcconville,J.r.,andBarkdoll,B.D.(nodate).
MetricsforsustainableWateruse.http://www.me.mtu.edu/
~jkgershe/sustainability/readings/Watkins_sustainable
_Water_%20use.pdf(accessed21August2015).
Wolfe,s.,andBrooks,D.B.(2003).Waterscarcity:analternative
viewanditsimplicationsforpolicyandcapacitybuilding.Natural
Resources Forum,27:99–107.
unitednations.(2005).Women2000andbeyond.http://
www.un.org/womenwatch/daw/public/Feb05.pdf(accessed
18Aug2015).
unitednationsenvironmentProgram.(nodate)examplesof
rainwaterHarvestingandutilisationAroundtheWorld.http://
www.unep.or.jp/ietc/publications/urban/urbanenv-2/9.asp
(accessed30April2015).
unWater.(2015a).compendiumofWaterQualityregulatory
Frameworks:WhichWaterforWhichuse?www.iwa-network.org/
which-water-for-which-use(accessed16october2015).
unWater.(2015b).unitednationsWorldWaterDevelopment
report2015:WaterforasustainableWorld.http://
unesdoc.unesco.org/images/0023/002318/231823e.pdf
(accessed16september2015).
unitedstatesenvironmentalProtectionAgency.(2010)control
andMitigationofDrinkingWaterlossesinDistributionsystems.
http://water.epa.gov/type/drink/pws/smallsystems/upload/Water
_loss_control_508_FinAlDec.pdf(accessed27May2015).
unitedstatesenvironmentalProtectionAgency.(2009).Gaining
operationalandManagerialefficienciesthroughWatersystem
Partnerships.http://water.epa.gov/type/drink/pws/smallsystems/
upload/2009_10_21_smallsystems_pdfs_casestudies
_smallsystems_gainingoperational.pdf(accessed15June2015).
unitedstatesenvironmentalProtectionAgency.(2013).Water
efficiencyforPublicWatersystems.http://water.epa.gov/type/
drink/pws/smallsystems/upload/epa816f13003.pdf(accessed15
June2015).
unitedstatesenvironmentalProtectionAgency.(2015).Water-
savingtechnologies.http://www.epa.gov/watersense/outdoor/
tech.html(accessed30April2015).
unitedstatesGeologicalsurvey.(2013).landsubsidencefrom
Ground-WaterPumping.http://geochange.er.usgs.gov/sw/changes/
anthropogenic/subside/(accessed10July2015).
vanderHoek,J.P.,izartenorio,J.l.,Hellinga,c.,vanlier,J.B.,
vanWijk,A.J.M.(2014).GreenvillageDelft–integrationofan
autarkicwatersupplyinalocalsustainableenergysystem.Journal
of Water Reuse and Desalination,4(3):154–163.
venketeswari,P.,leong,o.s.,andYong,n.H.(2014).seawater
desalinationusingforwardosmosisprocess.Journal of Water
Reuse and Desalination,4(1):34–40.
vestner,r.J.,Brooke,K.,andnicolet-Misslbeck,l.(2013).Water
reuseintheGazastrip,Palestine.Water Science & Technology,67
(4):729–736.
63 AlternAtiveWAterresourcescluster
Wu,J.-c.,shi,X.-Q.,Ye,s.-J.,Xue,Y.-Q.,Zhang,Y.,andYu,J.
(2009).numericalsimulationoflandsubsidenceinducedby
groundwateroverexploitationinsu-Xi-changarea,china.
Environmental Geology,57(6):1409–1421.
Zaneti,r.n.,etchepare,r.,andrubio,J.(2013).carwash
wastewatertreatmentandwaterreuse–acasestudy.Water
Science & Technology,67(1):82–88.
Zeng,X.t.,li,Y.P.,Huang,G.H.,andliu,J.(2015).Atwo-stage
interval-stochasticwatertradingmodelforallocatingwater
resourcesofKaidu-Kongqueriverinnorthwesternchina.Journal
of Hydroinformatics,17(4):551–569.
Zhai,J.,Xiao,H.W.,Kujawa-roeleveld,K.,He,Q.,andKerstens,
s.M.(2011).experimentalstudyofanovelhybridconstructed
wetlandforwaterreuseanditsapplicationinsouthernchina.
Water Science & Technology,64(11):2177–2184.
Zhu,t.,ringler,c.,andcai,Z.(n.D.).energyPriceand
GroundwaterextractionforAgriculture:exploringtheenergy-Water-
FoodnexusattheGlobalandBasinlevels.www.iwmi.cgiar.org/
eWMA/files/papers/energyprice_GW.pdf(accessed18June
2015).
WorldBank.(2015).reusingWastewaterforirrigationinBolivia–
FororAgainst?http://www.worldbank.org/en/news/feature/2015/
03/26/el-uso-de-aguas-residuales-para-riego-en-bolivia-a-favor-o-en
-contra(accessed1september2015).
Wicheins,D.(2006).economicincentivesencouragefarmers
toimprovewatermanagementincalifornia.Water Policy,8:
269–285.
Wittholz,M.K.,o’neill,B.K.,colby,c.B.,andlewis,D.(2008).
estimatingthecostofdesalinationplantsusingacostdatabase.
Desalination Amsterdam,229:10–20.
WorldBusinesscouncilforsustainableDevelopment.(n.D.).the
WscsDGlobalWatertool©.www.wbcsd.org/work-program/
sector-projects/water/global-water-tool.aspx(accessed21August
2015).
WorldWildlifeFund.(2011).AssessingWaterrisk:APractical
ApproachforFinancialinstitutions.report.www.deginvest.de/
DeG-englische-Dokumente/PDFs-Download-center/DeG-WWF
_Water_risk.pdf(accessed21August2015).
innovating technology, pioneering science, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change.innovating technology, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change.innovating technology, pioneering science, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change.innovating technology, pioneering science, connecting people, inspiring change. pioneering science, connecting people, leading practice, inspiring change.innovating technology, pioneering science, connecting people, leading practice, innovating technology, pioneering science, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change.innovating technology, connecting people, leading practice, inspiring change. pioneering science, connecting people, leading practice, inspiring change.innovating technology, pioneering science,
inspiring change
Anna van Buerenplein 48, 11th Floor2595 DA The HagueThe Netherlands+ 31 703 150 [email protected]
address
phone email
IWA Global Operations
www.iwa-network.org
IWA Head Office | Alliance House, 12 Caxton Street, London SW1H 0QS, UK | Company registered in England No. 3597005 | Registered Charity (England) No. 1076690