Holistic blue water use and life cycle cost savings of ...Aug 02, 2017 · Water yield loss and...
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Holistic blue water use and life cycle cost savings of domestic and agricultural rainwater harvesting at the watershed scale in the Southeast US Santosh R. Ghimire 1 and John M. Johnston 2 1 Global Sustainability and Life Cycle Consultant (GSLC Consultant) LLC 2 USEPA, Office of Research and Development The Annual Georgia Environmental Conference August 23-25, 2017 | Jekyll Island, Georgia | USA
Transcript of Holistic blue water use and life cycle cost savings of ...Aug 02, 2017 · Water yield loss and...
Holisticbluewateruseandlifecyclecostsavingsofdomesticandagriculturalrainwaterharvesting
atthewatershedscaleintheSoutheastUS
SantoshR.Ghimire1 andJohnM.Johnston21GlobalSustainabilityandLifeCycleConsultant
(GSLCConsultant)LLC2USEPA,OfficeofResearchandDevelopment
TheAnnualGeorgiaEnvironmentalConferenceAugust23-25,2017|JekyllIsland,Georgia|USA
AGENDA§ INTRODUCTION§ CONTEXT
§ Holisticimpactassessmentandcostsavingsofrainwaterharvestingatthewatershedscale
§METHODS§ RESULTS§ SUMMARY§ REFERENCES
Challengesofmanagingwaterresourcesduetoclimatechangeimpactsandpopulationgrowth
During1980-2012theweatherandclimateintheU.S.haveresultedinmorebilliondollarsdamageevents(Carteretal.2014)
§ TheSoutheastaffectedbymorebillion-dollardisastersthananyotherregion
From1970to2007mostoftheSoutheastU.S.receivedheavydownpoursinrecentautumnswhilemoderate-to-severedroughtincreasedinspringandsummer(12%and14%)(USGCRP 2012)
INTRODUCTION
OriginalFiguresource:NOAANCDC(2013)http://www.ncdc.noaa.gov/billions/events
RWHGreenInfrastructure
§ Rainwaterharvesting(RWH)practicesarereceivingrenewedinterestasgreeninfrastructureoptions
§ PotentialbenefitsofRWH:§ reducedenvironmentalandhumanhealthimpacts§ reducedstormwater runoffandcombinedsewer
overflows§ watersavingsandeconomicbenefits
§ Lackofscientificknowledgeofholisticimpacts(lifecycleenvironmental,humanhealth,andeconomicviability)ofRWHhinderstheformulationofclearpoliciesforitsuse
Energy/Material
EnvironmentalImpacts
Harvestedrainwater
Agricultural RWH
Domestic RWH
AgriculturalRWH
Ghimireetal.(2014)
1.Extraction
2.Manufac.
3.Transport
4.Use
5.ReuseRecycleRecovery
6.Disposal
LifeCycleAssessment(LCA):aholisticperspective
ISO14040CradletoGravePerspective:“Entirelifecycleofaproduct,fromrawmaterialextractionandacquisition,throughenergyandmaterialproductionandmanufacturing,touseandendoflifetreatmentandfinaldisposal.”(ISO2006)
CONTEXT
ObjectivesandScope
ComprehensivelyaddressedtheholisticimpactsofRWHatthewatershedscale§ FossilFuelDepletion§ MetalDepletion§ OzoneDepletion§ Acidification§ Smog§ Ecotoxicity-total§ Eutrophication-total§ HumanHealthCriteriaPollutants§ HumanHealthCancer§ HumanHealthNon-cancer
Onlythefirstsix(bolded)impactswillbediscussed
§ EnergyUse§ GlobalWarmingPotential§ BlueWaterUse§ GreenWaterUse§ LifeCycleWaterBalance§ LifeCycleEnergyCostSavings
METHODS
§ Watershedselection§ RWHsystemsdesignandadoptionrates§ Holisticimpactassessmentatthewatershedscale
§ Lifecycleassessment(LCA)§ Lifecyclecostassessment(LCCA)§ Holisticwaterbalance
WatershedSelection
Albemarle-Pamlico basin with 25% adoption rate for domestic RWH systems (1 dot = 100)
Watershed Totalarea(km2)
Averagefarmarea(km2)
Totalfarmarea(km2)
Numberofagricultural
RWHsystems
Urbanarea(%)
NumberofdomesticRWH
systems
BackCreek
152 0.34 11.7 34 18 5,768
Sycamore 41.5 0.42 0.91 2 49 10,296GreensMill
33.9 1.6 4.6 3 62 11,582
Watershed Characteristics
RWHSystemsDesignandAdoptionRates
Near-optimalRWHsystemdesignsminimizedinfrastructure(Ghimireetal.2014):
§ ThedomesticRWHsystems:§ apolyethylene(PE)storagetankof6.2m3
§ reducedpipelength(5m)ofchlorinatedpolyvinylchloride
§ nopumporpumpingenergy
§ TheagriculturalRWH:§ polyvinylchloridepipeof150m§ PEstoragetankof606m3
§ nopumporpumpingenergy.
RWHadoptionratesof25%,50%,75%,and100%
Schematic of domestic RWH
Schematic of agricultural RWH
(Figs. From Ghimire et al. 2014)
HolisticImpactAssessmentattheWatershedScale
Iw = changeinwatershed-scaleimpactswithrespecttoconventionalwatersupply(Units,e.g.,TJforenergydemand)A=RWHadoptionrates:25%,50%,75%,
and100%(decimal)Nt = totalnumberofRWHsystemsQy =annualwaterdemandforahousehold
toiletflushingoracropirrigation(m3y-1)T=servicelifeofRWHsystem(50yr)∆i =icon– irwh =differenceinimpactper1m3 of
rainwaterdeliverywithrespecttoconventionalwatersupply (Units/m3)
irwh and iconaretheLCIAimpactsperm3 ofrainwaterandconventionalwatersupply,respectively
Iw =Ax Nt x Qy x Tx ∆i
Watershed-scaleLCAsystemboundary
LCA
§ Apriorstudy(Ghimireetal.2014)providedfunctionalunitLCIAimpacts(perm3 waterdelivery)of:§ domesticRWHathouseholdlevel§ agriculturalRWHatfarmlevel§ conventionalmunicipaldrinkingwaterfortoiletflushing§ wellwaterforirrigation
§ CalculationswereperformedusingOpenLCA (OpenLCA 2013)linkedtothelifecycleinventorydatabasesandtheEPA’sLCIAmethods,andTRACI(ToolfortheReductionandAssessmentofChemicalandotherenvironmentalImpacts) version2.0(USEPA2013)
§ Resultsscaledtowatershed
LCCA
Lifecyclecostassessment(LCCA)ofanagriculturalRWHsystemperformedLCCAdefinedasthesumofthepresentvaluesofaproject,product,ormeasureoverthelifetime(U.S.guidelinesforLCCA)(Register1999):
§ investmentcosts§ capitalcosts§ installationcosts§ energycosts§ operatingcosts§ maintenancecosts§ disposalcosts
IllustratedaholisticviewofeconomicviabilityofagriculturalRWHbycombiningthecumulativeenergycostsavingswithlifecyclecosts
HolisticWaterBalanceHolisticlifecyclewatersavingsestimatedbyincorporatingthelossinannualwateryieldduetowatershed-wideRWH:
BH =BUy – Wa xRy
BH =annualbluewatersavingsduetodomesticoragriculturalRWHcomparedtoconventionalwatersuppliesbyintegratingrainfall(m3/y)BUy =annualnetsavingsinlifecyclebluewateruse(m3/y)Wa =watershedareacontributingtototalwateryield(m2)Ry =thelossinannualwateryieldduetodomesticoragriculturalRWHcomparedtono-RWHannualwateryield(m/y)
Thelossinwateryieldincorporatesrainfallinfluencescombining:§ surfacerunoff§ lateralflow§ groundwatercontribution(returnflowfromshallowaquifer)§ transmissionlossesand§ pondabstractions.
LifeCycleEnergyCostSavings
Potentialtranslatedcostsavingsduetowatershed-widelifecycleenergyusewerederived:
Cs =2.78x105 xPe xEsCs =potentialcostsavings($)Es =cumulativeenergysavings(TJ)Pe =energyprice ($0.103/kWh)(USEIA2014)2.78x105 =aconversionfactor(i.e.,1TJ=2.78x105 kWh)
RESULTS
ReductioninwatershedscaleimpactsofdomesticRWHadoptionwithrespecttoconventionalmunicipaldrinkingwaterinthreewatersheds:BackCreek=BC,SycamoreCreek=SC,GreensMill=GM
LCAimpactcategory Unit
Reductioninwatershed-scaleimpactsofdomesticRWHadoptionsinthreewatersheds
Reduction(%)
100% 75% 50% 25%
BC SC GM BC SC GM BC SC GM BC SC GM
EnergyDemand
TJ 85 152 171 64 114 128 42 76 85 21 38 43 58
GlobalWarming
MgCO2 eq
4667 8331 9372 3501 6248 7029 2334 4166 4686 1167 2083 2343 52
GreenWaterUse
Mm3 -11 -19 -21 -8 -14 -16 -5 -10 -11 -3 -5 -5 --
BlueWaterUse
Mm3 13 23 26 10 17 19 6 11 13 3 6 6 100
The relative reductions in impacts ranged from 52% (Global Warming) to 100% (blue water use)
RESULTS
The relative reductions in impacts ranged from 76% (Global Warming) to 100% (blue water use)
LCAimpactcategory Unit
Reductioninwatershed-scaleimpactsofagriculturalRWHadoptionsinthreewatersheds
Reduction(%)
100% 75% 50% 25%
BC SC GM BC SC GM BC SC GM BC SC GM
EnergyDemand
TJ 838 49 74 629 37 55 419 25 37 210 12 18 78
GlobalWarming
MgCO2 eq
40369 2375 3562 30277 1781 2671 20185 1187 1781 10092 594 890 76
GreenWaterUse
Mm3 -154.5 -9 -14 -116 -7 -10 -77 -5 -7 -39 -2 -3 ---
BlueWaterUse
Mm3 154.7 9 14 116 7 10 77 5 7 39 2 3 100
ReductioninwatershedscaleimpactsofagriculturalRWHadoptionwithrespecttoconventionalpracticesinthreewatersheds:BackCreek=BC,SycamoreCreek=SC,GreensMill=GM
RESULTSWater yield loss and holistic water balance for 100% domestic RWH and agricultural RWH adoption in three watersheds
From a life cycle perspective, the water loss due to RWH can be offset by life cycle blue water savings
-1.0-0.50.00.51.01.52.02.53.0
BackCreek Sycamore GreenMills
Holisticann
ualbluewaterbalance
(Mm3)
Holisticannualwaterbalance
100%AgriculturalRWH
02468
10121416
No-RW
H
100%
DRW
H
100%
ARW
H
No-RW
H
100%
DRW
H
100%
ARW
H
No-RW
H
100%
DRW
H
100%
ARW
H
BackCreek Sycamore GreensMill
Annu
alwateryieldloss(m
m)
Annualwateryieldloss
Annualwateryieldloss
RESULTSLife cycle energy cost savings due to cumulative energy reductions by domestic RWH (DRWH) and agricultural RWH (ARWH) adoption rates in three watersheds:
Back Creek (BC)Sycamore Creek (SC)Greens Mill (GM)
24
18
12
6
0
5
10
15
20
25
30
100 75 50 25
Costsa
vings,$M
Adoptionrate,A(%)
DRWH(BC) DRWH(SC) DRWH(GM)ARWH(BC) ARWH(SC) ARWH(GM)
SUMMARY§ AholisticviewofenvironmentalandeconomicviabilityofdomesticandagriculturalRWHatthe
watershedscaleinthesoutheasternU.S.wasdiscussed§ Watershed-scaleimpactreductionsduetoagriculturalRWHwere17timeshigherforBackCreekthan
Sycamoreduetomorefarmsintheformerwatershed§ DomesticRWHimpactreductionsforSycamoreandGreensMillweretwicethoseofBackCreekdueto
morehouseholdsinthefirsttwowatersheds§ HolisticwaterbalanceanalysisrevealedgreaterannualbluewatersavingsforagriculturalRWH(at100%
adoption)forBackCreek(2.4Mm3/y)thanSycamoreCreek(0.1Mm3/y)§ Potentialmaximumlifetimeenergycostsavingswereestimatedat$5Mand$24Mcorrespondingto
domesticRWHinGreensMillandagriculturalRWHinBackCreek§ 25%DRWHandARWHadoptionledtoanumberofecologicalandhumanhealthbenefitsincluding:
§ bluewaterusereductionrangingfrom2–39Mm3
§ cumulativeenergysavingsof12–210TJ§ reducedglobalwarmingpotentialof600–10,100MgCO2eq.
§ Impactsvarywithsystemdesign,RWHregulations,wateruse,watertreatmentprocessesandpumpingenergy
§ Themethodologyisgenerallyapplicabletoregionswithcomparablewatershedcharacteristicsandwatertreatmentoptions
§ RWHsustainabilityshouldbewellstudiedacrossscales§ UpscalingagriculturalRWHimpactsattheriverbasinscale§ CouplingofRWHwithcentralizedwatersystemsaswellaswithinnovativedecentralizedwastewatermanagementoptions(e.g.,waterreuse)
SUMMARY
1. NOAA2013.BillionDollarWeather/ClimateDisasters,ListofEvents.NationalOceanicandAtmosphericAdministration,Washington,D.C.
2. Carteretal.2014.Ch.17:SoutheastandtheCaribbean.ClimatechangeimpactsintheUnitedStates.U.S.GlobalChangeResearchProgram,Washington,D.C.
3. Ghimire,S.R.,andJ.M.Johnston2017.Holisticimpactassessmentandcostsavingsofrainwaterharvestingatthewatershedscale.ElemSci Anth 5.
4. Ghimireetal.2014.LifeCycleAssessmentofDomesticandAgriculturalRainwaterHarvestingSystems.EnvironmentalScience&Technology48(7):4069-4077.
5. ISO2006.Environmentalmanagement— Lifecycleassessment— Principlesandframework.ISO14040.Switzerland:InternationalOrganizationforStandardization.
6. OpenLCA 2013.OpenLCA,ModularOpenSourceSoftwareforSustainabilityAssessment.GreenDelta.
7. Register,F.2009.ExecutiveOrder13514,FederalLeadershipinEnvironmental,EnergyandEconomicPerformance.FederalRegister.TheWhiteHouse,USA.
8. USEIA2014.Electricity.U.S.EnergyInformationAdministration,USA.
9. USEPA2013.Toolforthereductionandassessmentofchemicalandotherenvironmentalimpacts(TRACI).U.S.EnvironmentalProtectionAgency,USA.
10. USGCRP2012.RegionalClimateImpacts:Southeast,U.S.GlobalChangeResearchProgram.
REFERENCES
§ Theopinionsexpressedorstatementsmadehereinaresolelythoseoftheauthors.Mentionoftradenamesorcommercialproductsdoesnotconstituteendorsementorrecommendationforuse.
§ WethankMikeCyterski (EPA)fortechnicalreview.
DISCLAIMER/ACKNOWLEDGMENTS
