water Article A Robust Neutrosophic Modeling and Optimization Approach for Integrated Energy-Food-Water Security Nexus Management under Uncertainty FirozAhmad1,2,†,‡ ,ShafiqAhmad 3,*,‡ ,MazenZaindin4andAhmadYusufAdhami1,‡ 1 DepartmentofStatisticsandOperationsResearch,AligarhMuslimUniversity,Aligarh202002,India; [email protected](F.A.);[email protected](A.Y.A.) 2 IndianStatisticalInstitute,203B.T.Road,Kolkata700108,India 3 IndustrialEngineeringDepartment,CollegeofEngineering,KingSaudUniversity,P.O.Box800, Riyadh11421,SaudiArabia 4 DepartmentofStatisticsandOperationsResearch,CollegeofScience,KingSaudUniversity,P.O.Box2455, Riyadh11451,SaudiArabia;[email protected] * Correspondence:ashafi[email protected] † Currentaddress:IndianStatisticalInstitute,203B.T.Road,Kolkata700108,India. ‡ Theseauthorscontributedequallytothiswork. Abstract: Naturalresourcesareaboonforhumanbeings,andtheirconservationforfutureuses isindispensable.Mostimportantly,energy-food-watersecurity(EFWS)nexusmanagementisthe utmostneedofourtime.Aneffectivemanagerialpolicyforthecurrentdistributionandconservation tomeetfuturedemandisnecessaryandchallenging.Thus,thispaperinvestigatesaninterconnected anddynamicEFWSnexusoptimizationmodelbyconsideringthesocio-economicandenvironmental objectiveswiththeoptimalenergysupply,electricityconversion,foodproduction,waterresources (cid:1)(cid:2)(cid:3)(cid:1)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:1) allocation,andCO2emissionscontrolinthemulti-periodtimehorizons.Duetoreal-lifecomplexity, (cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7) variousparametersaretakenasintuitionisticfuzzynumbers. Anovelmethodcalledinteractive Citation:Ahmad,F.;Ahmad,S.; neutrosophicprogrammingapproach(INPA)issuggestedtosolvetheEFWSnexusmodel.Toverify Zaindin,M.;Adhami,A.Y.ARobust andvalidatetheproposedEFWSmodel,asyntheticcomputationalstudyisperformed.Theobtained NeutrosophicModelingand solution results are compared with other optimization approaches, and the outcomes are also OptimizationApproachfor evaluatedwithsignificantpracticalimplications.Thestudyrevealsthatthefoodproductionprocesses IntegratedEnergy-Food-Water requiremorewaterresourcesthanelectricityproduction,althoughrecycledwaterhasnotbeenused SecurityNexusManagementunder forfoodproductionpurposes.Theuseofacoal-firedplantisnotaprominentelectricityconversion Uncertainty.Water2021,13,121. source.However,naturalgaspowerplants’serviceisalsooptimallyexecutedwithamarginalrateof https://doi.org/10.3390/w13020121 production.Finally,conclusionsandfutureresearchareaddressed.Thiscurrentstudyemphasizes howtheproposedEFWSnexusmodelwouldbereliableandbeneficialinreal-worldapplicationsand Received:28November2020 helppolicy-makersidentify,modify,andimplementtheoptimalEFWSnexuspolicyandstrategies Accepted:6January2021 forthefutureconservationoftheseresources. Published:7January2021 Publisher’sNote: MDPIstaysneu- Keywords: Energy-Food-Watersecuritynexusmanagement; robustmodelingandoptimization tralwithregardtojurisdictionalclai- method; intuitionistic fuzzy parameters; interactive neutrosophic programming approach; opti- msinpublishedmapsandinstitutio- malsocio-economicandenvironmentalprotectionpolicies nalaffiliations. 1. Introduction Copyright:©2021bytheauthors.Li- Naturalresourcesarepreciousandessentialforhumanlives. Primarily,energy,food, censee MDPI, Basel, Switzerland. andwater(EFW)arethebasicneedsfordailylifeandhumansurvival. Arapidincrease Thisarticleisanopenaccessarticle inthepopulationsignificantlyenhancestheseresources’demand,causingdepreciation distributedunderthetermsandcon- ditionsoftheCreativeCommonsAt- anddepletionintheseresources’utilityrates. Asaresult,theacquisitionandconservation tribution (CC BY) license (https:// oftheseresourcesbecomeindispensabletomeetfutureneeds. Theseresourcesareinter- creativecommons.org/licenses/by/ relatedandaffecteachother,eitherdirectlyorindirectly.Thus,theinter-dependencenature 4.0/). Water2021,13,121.https://doi.org/10.3390/w13020121 https://www.mdpi.com/journal/water Water2021,13,121 2of27 ofEFWresourceshasbeenexploredasasortofcompositenetwork,calledenergy-food- water security (EFWS) nexus management. According to the EIA report, [1] in the US, approx. 89%oftheelectricitywasgeneratedbycoalandnatural-gas-firedpowerplants, whereas a massive amount of water is consumed for pumping and cooling purposes. Presently,about1.29billionpeoplethroughouttheworldarenotaccessingelectricity[2]. Tomeetsuchamassiveelectricitydemand,theaccumulationofwaterresourcesforcoal- firedpowerplantsandthefuelextractionprocesswillbechallenging.Moreover,population growthisexpectedtoincreaseconcerningfooddemand,about53%by2050[3]. Itcompels theneedtorealizeandidentifytheinteractionsamongvariousresourcesrequirementsto fulfillfuturedemandsaffectingtheEFWSnexussystem’scomposition. According to [3]’s report, food production and supply purpose consume approx. 31%ofglobalenergy.AnincreaseinthemasspopulationresultsinhigherdemandforEFW resourcesdrastically[3]. By2050,apredictiveanalysisindicatesthattheworldpopulation willincreasebyabout49%[4].Furthermore,itisnoticedthatintegratedEFWSnexusmodel arecomplexanddynamicduetonotonlytheinter-dependenciesofthesethreeresources that influence each other at various level, but also the involvement of different factors suchaseconomic,social,andenvironmental,etc. whichmadeitmorecomplicated. Nexus managementisgainingmoreattentionduetoitsprimeconcernsaboutenergy,food,and watersecurity. ItisexpectedthattheproposedEFWSnexusmodelwouldbewell-enough toaddressandanswerthemostcriticalqueries,suchas“optimaldistributionofresources,” “balancingthetrade-offbetweentotaleconomiccostandCO emissions”,“evaluatingand 2 designingthepoliciesandnecessaryinitiatives.” Quantitativeoptimizationmodelsare powerfultoolsinidentifying,assessing,andsummarizingthecriticalfactorsandprovides globallyacceptableoutcomestofacilitatethedecisionsandrelevantprocesses. Uncertain parameters are often encountered in the EFWS decision-making model. Unlikefuzzyandrandomparameters,uncertainparametersaredepictedastriangularor trapezoidalintuitionisticfuzzynumbers. Afuzzyparameteronlydealswiththedegreeof belongingness(acceptance)oftheelementintoafeasiblesolutionset. Itdoesnotconsider thedegreeofnon-belongingness(rejections)oftheelementintothesamefeasiblesolution set,anintegratedpartofthedecision-makingprocesses. Furthermore,uncertaintydue torandomnessisindicatedwithrandomparameters. Sometimes,itmaynotbepossible to have historical data for which the random parameters are estimated. According to somespecifiedprobabilitydistributionfunction,theforecastingpatternandparameters estimation of random variables is much dependent on the behavior and nature of the historical data. An intuitionistic fuzzy parameter deals with the degree of belonging- ness (acceptance) and degree of non-belongingness (rejections) of the element into the same feasible solution set, simultaneously. For example, if the decision maker intends toquantifythecostoftransportationwithsomeestimatedvalue,suchastransportation costfromwaterresourceszonestoelectricityconversionplantis54$,thenthemostlikely estimatedintervalwouldbe50–58$,alongwithsomehesitationdegreethatmaybegivenas 48–60$,whichensureslessviolationofriskswithdegreeofacceptanceandnon-acceptance. Also, there is no scope for the historical data while dealing with intuitionistic fuzzy parameters(Ahmadetal.[5]). Thus,theprimemotivebehindtheselectionofintuition- isticfuzzyparametersistoavoidtheshortcomingsoffuzzyvaguerandomparameters. ThereforethequantitativeandanalyticalstudyofEFWSnexusmanagementnetworkhas theutmostneedforthetimeinbalancingtheequilibriumamongoptimalresourceuse, socio-economicandenvironmentalobjectives,anddesigningfruitfulpolicies. Manypast studiesconfronttheresearchdomainofEFWSnexus. Still,mostofthemareconfinedto either individual resource management fields such as water sector, energy-conversion, agricultural production, or two sectors such as water-energy nexus, particular prob- lemssuchaswateruses,ortheoreticalandconceptualdevelopmentoftheEFWSnexus. This study has unified all three resources and the socio-economic and environmental objectivesatasingleplatform. Water2021,13,121 3of27 Aninteractiveneutrosophicprogrammingapproach(INPA)isdevelopedtosolve theproposedEFWSnexusmodel. ThediscussedINPAmanagesindeterminacyorneutral thoughtswhilemakingdecisionsformultiobjectiveoptimizationproblems. Neutralityis theregionofpropositions’valuesnegligence,whichexistsbetweentruthandfalsitydegree. Thus, theneutrosophicdecisionsettheoryisamoregeneralizedandflexibleapproach thanthefuzzyandintuitionisticfuzzysettheoryduetoindeterminacydegree. Therefore, theproposedsolutionapproachcanalsoberegardedasacontributiontotheoptimization techniquedomain. Themainaimandobjectiveofthispaperaretoexploreandhighlightanintegrated modeling and optimizing system for EFWS nexus management. A useful quantitative andanalyticalmodelwouldestablishthetrade-offsamongobjectivesandconstraintsto achievethesocio-economicdemandsandenvironmentalimpactswhileusingtheenergy, food,andwaterresources. TheproposedEFWSmodelinherentlyestimatesthevarious costsassociatedwiththelimitedEFWresources,socio-economicdemands,andCO emis- 2 sionsabatementoverthemulti-periodplanninghorizons. Itisalsocapableofdealingwith moregeneralizeduncertaintyduetohesitationwhiledepictingtheparameters. Various inter-connected components such as production, distribution, and consumption of the EFWSnexusmodelarequantitativelyandanalyticallyexamined. TheproposedEFWS nexusmodel’smainadvantagecanberealizedbyhavingitbeconsistentwithandcompe- tentcomparedwithreal-lifemanagementproblems. Thecurrentstudyalsodemonstrates howtheseresourcescanbeusedoptimallyandhowtheycanbeconservedtomeetfuture demand. Practical implications are well addressed based on obtained solution results. Post-optimalityanalysesareperformedtogenerateandidentifythemostpromisingsolu- tionsunderdifferentriskfactors. Therefore,thepresentedstudycanhelpdecision-makers designtheoptimalpoliciesandstrategiesforEFWSnexusmanagementunderuncertainty. 2. LiteratureReview Over recent decades, optimal use of resources has made significant impacts in re- search and development fields to identify, quantify, and analyze the decision-makers’ policiesandstrategieswhilemanagingtheEnergy-Water-Foodnexusmanagementsys- tem. ThemosteffectiveandindispensablemodelingtextureoftheEFWSnetworkunder various uncertainties was developed by many authors, practitioners, and researchers. Bieberetal.[6]developedamethodologyandoutlookforresilientandsustainablesup- plychainplanningintheenergy-water-foodnexusatthecity-regionlevel. Uenetal.[7] proposedaholisticapproachforthesynergeticmanagementoftheWater-Energy-Food nexusandappliedNSGA-IItosolvethemodel. Tsolasetal.[8]discussedanovelwater- energy nexus optimization and presented a case study at the country and state level. Namanyetal.[9]alsoaddressedaresourcesmanagement-orientedEnergy-water-Food nexus optimization model with a real-life application. Gao et al. [10] introduced a wa- ter–food–energynexusmanagementmodelforminimizingthecost-coalandproduction- cost of agricultural products. Zhang et al. [11] attempted to develop an assessment- optimizationmethodologyforWater-Energy-Foodnexussynergiesandconcludedwater supplyasacriticalfactorinthemodelingapproach. Lietal.[12]exploredthesynergies withintheWater-Energy-FoodnexussystemandpresentedasacasestudyShenzhencity using the proposed model. Hamidov and Helming [13] presented a theoretical study ontheever-increasingliteratureontheWEFnexusmanagementalongwithconcluding remarks. Saifetal.[14]discussedanintegratedenergy-water-foodsupplychainoptimiza- tionmodelwithacasestudy. Jietal.[15]addressedacrop-biomassproductionplanning problemwithfood-energy-waternexusunderuncertainties. Thedevelopedmodelassists thedecision-makersinadoptingadequatepoliciesandstrategies. Okolaetal.[16]designed amultiobjectiveoptimizationframeworktohighlightthecomplexitylinkedwithFood- Energy-WaterNexusandsuggestedtheoptimalproductionandresourceconsumption policiesoverdifferentplanninghorizons. Water2021,13,121 4of27 Manyresearchersdiscussedtheirworkbyincorporatingdifferentsortsorformsof uncertaintyinthewater,energy,andfoodnexusoptimizationmodelasfarasuncertainties areconcerned. Wesummarizedsomerecentdevelopmentsandadvancedstudiesinthe uncertaintydomainintheEFWSnexusmodel. Lietal.[17]alsodevelopedanintegrated agriculturalwater-energy-foodnexusmanagementmodelunderfuzzydemandsforthe resourcesandappliedtoacasestudydata-set. Lietal.[18]suggestedawater-food-energy nexusoptimizationoutlookforirrigatedagricultureunderdualstochasticuncertaintyof available water resources and validated the model based on a real case study. Li et al. [19]addressedtheoptimization-assessmentofenergy,food,water,andlandframework forbioenergyproductionininterval-valueduncertaintyanddemonstratedacasestudy in northeast China. Yu et al. [20] explored a copula-based fuzzy interval-random pro- grammingapproachunderjoint-riskandimplementedareal-worldcasestudyinHenan Province, China. Elsayed et al. [21] studied a Nile Water-Food-Energy Nexus manage- mentsystemanddepictedatrade-offsopportunityamongtheresourcesusepoliciesto acasestudyinSudan. TanandZhang[22]suggestedarobustfractionalprogramming approachtoaddresstheagriculturalwatermanagementmodelundertheriskuncertainty andvalidatedusingsimulationsandcomparisonswithexistingalternatives. Hurford[23] alsoidentifiedandassessedtheimpactsofwater-energy-foodsecurityindevelopingcoun- tryandconcludingremarksaremadebasedonthestudy. GovindanandAl-Ansari[24] discussedaflexiblecomputationalframeworkforintegratedenergy-water-foodsecurity underriskfactorsandperformedacasestudyoftheagriculturalsectorintheStateofQatar. Jietal.[25]developedaninexacthybridmodelforfood-energy-waternexusmanagement underthemixed-characteruncertaintiesandpresentedpracticalimplicationsbasedonthe casestudyinShandong,China. Yuetal.[26]propoundedaneffectivewater-energy-food nexusplanningsystem,andamulti-levelintervalfuzzycredibility-constrainedprogram- mingissuggestedtodealwiththeuncertaintiesandthenimplementedonareal-casestudy inHenanProvince.Furthermore,Hangetal.[27]designedthelocalfood,energyandwater productionsystembasedonthenexusconcept. Martinez-Hernandezetal.[28]developed thenewsoftwaretoolfortechno-ecologicalsimulationoflocalfood-energy-watersystems. Also,anintegratednexusmodelingnetworkisscarceintheliterature,whichcanintro- duceandimplementtheenergy,food,andwaterresourcesefficiently. Inassociationwith socio-economicobjectives,incorporatingenvironmentalprotectionsintoarobustmodeling andoptimizationframeworkisalsotheneedforthecurrentstate-of-art. TheEFWSnexus management perspective is necessary for the quantitative and qualitative study of the complexinterconnectednetworkandevaluatingtheoutcomesforoptimalpoliciesand developmentforthewholesystem. 3. DevelopmentofEnergy-Food-WaterSecurityNexusModel TheproposedEFWSmodelisformulatedtooptimizeandmanagetheavailableenergy, food,andwaternexusresourcesinintuitionisticfuzzyuncertaintyoverdifferentperiods. Thevariouscostsassociatedwiththeoperations,production,supply,andCO emissions 2 abatementarecontemplatedoverthesocio-economicandenvironmentallyorientedobjec- tive. ThequantityofCO emissionsisalsoachallengingtaskfromtheenvironmentalpoint 2 ofview. Thesevereimpactofsuchtoxicemissionsaffectsbothfloraandfauna. Thus,the developedmodelintegratesandadherestoEFWSnexusmanagement’sessentialaspectsby undertakingthevagueuncertaintyamongdifferentparameters. Theinter-connectedcom- ponentintheproposedEFWSnexusmanagementmodelisshowninFigure1,whichalso signifiestheresearchdomainofthisstudy. Theusefulnotionsanddescriptionsusedinthe proposedEFWSmodelaredepictedinTable1. Theoptimalallocationoftheenergy-supply quantityofcoalandnaturalgas,theavailablecapacityofthepowerplanttoproduceelec- tricity,amountofgroundandsurfacewaterrequiredforfoodproduction,thevolumeof ground,surface,andrecycledwaterneededforelectricityproduction,andsocio-economic demandsforEFW(Energy,FoodandWater)turnoverinawell-specifiedproductionplan- ningperiodsaretheprimecharacteristicfeaturesoftheproposedEFWSmodel. Thefirst Water2021,13,121 5of27 objectiveisdevelopedtoreducethetotaleconomiccostcomprisingenergy-supplycostsfor electricityproduction,costsofelectricity-production,costsofwater-delivery,costsoffood production,andfinallyCO emissionsabatementcostsovertimehorizons. Thesecond 2 objectivemitigatestheCO emissionsproducedduringelectricityconversionandfood 2 production,respectively. Alltherelatedparametersaretakenastriangularintuitionistic fuzzyandresolvedintotheircrispformusingarobustrankingfunction(SeeSection5.1). Figure1.Inter-dependencerelationshipsofEnergy-Food-Watersecuritynexusmanagementsystem. Table1.Notionsanddescriptions. Indices Descriptions e Associatedwiththeenergy-production f Associatedwiththefoodproduction j ∈ J Denotesthetypesofavailableenergysupplyandpowerconversionplant t ∈ T Representstheeffectiveplanningtimeperiodssuchasatimehorizonforenergy, foodand watersecuritymanagement w Associatedwiththewater-resourcesuse Decisionvariables es Amountofavailableenergysupplyjintimeperiodt(PJ) j,t x Amountofelectricityconversionbyapowerplantousingenergysupplyjintimeperiodt(PJ) j,t f gw Quantityofgroundwaterconsumedinfoodproductionprocessesintimeperiodt(bbl) t f sw Quantityofsurfacewaterconsumedinfoodproductionprocessesintimeperiodt(bbl) t gwe Groundwaterquantitydeliveredtopower-conversionplantjintimeperiodt(bbl) j,t swe Surfacewaterquantitydeliveredtopower-conversionplantjintimeperiodt(bbl) j,t rwe Amountofrecycledwatersenttopower-conversionplantjintimeperiodt(bbl) j,t fo Totalquantityoffoodproductionintimeperiodt(ton) t Water2021,13,121 6of27 Table1.Cont. Parameters (cid:93) esc Averagecostassociatedwithenergysupplyjintimeperiodt(million$/PJ) j,t f(cid:102)cj Fixedcostassociatedwithpowerconversionplantj(million$) pc Averageoperationalcostincurredoverelectricityproductionbypowerconversionplantjin (cid:103)j,t timeperiodt(million$/PJ) (cid:93) f cgw Totalcostrelatedtogroundwatersupplyforfoodproductionintimehorizont($/bbl) t (cid:94) cgwe Totalcostrelatedtogroundwatersupplyforpowerconversionplantjintimehorizont($/bbl) j,t (cid:93) f csw Totalcostrelatedtosurfacewatersupplyforfoodproductionintimehorizont($/bbl) t (cid:93) cswe Totalcostrelatedtosurfacewatersupplyforpowerconversionplantjintimehorizont($/bbl) j,t (cid:93) crwe Totalcostrelatedtorecycledwatersupplyforpowerconversionplantjintimehorizont($/bbl) j,t c(cid:103)fot Unitcostassociatedwithfoodproductionintimeperiodt(million$/ton) cea TotalcostofCO emissionabatementforelectricityproductionintimeperiodt($/kg) (cid:103)t 2 cc UnitsofCO emissionperunitofelectricityproductionbypowerconversionplantjintime (cid:103)j,t 2 periodt(millionkg/PJ) c(cid:103)fat TotalcostofCO2emissionabatementforfoodproductionintimeperiodt($/ton) f(cid:102)ft UnitsofCO2emissionperunitoffoodproductionintimeperiodt(millionkg/ton) f(cid:103)ej,t Unitenergycarrierperunitofelectricityproductionfortransformationtechnique j intime periodt(PJ/PJ) av Totalavailableenergysupplyjintimeperiodt(PJ) (cid:103)j,t (cid:94) f aer Maximumunitofelectricityavailableforfoodproductionintimeperiodt(PJ) t,max (cid:94) aerw Maximumunitofelectricityavailableforwatercollection,treatmentandsupplyintimeperiod t,max t(PJ) e(cid:102)rf Demandofunitenergyforfoodproductionintimeperiodt(PJ/ton) t e(cid:102)rw Demandofunitenergyforwatercollection,treatmentandsupplyintimeperiodt(PJ) t d(cid:102)ee Socio-economicdemandforenergy(orelectricity)intimeperiodt(PJ) t d(cid:102)ef Socio-economicdemandforfoodintimeperiodt(ton) t w(cid:103)ft Unitsofwaterconsumptionperunitoffoodproductionintimeperiodt(bbl/ton) sy Maximumquantityofavailablegroundwatersafeyieldintimeperiodt(bbl) (cid:102)t asw Maximumquantityofavailablesurfacewaterintimeperiodt(bbl) (cid:103)t arw Maximumquantityofavailablerecycledwaterintimeperiodt(bbl) (cid:103)t (cid:93) tmcc MaximumpermissableCO emissionduringplanningperiods(millionton) 2 δ Lossfactorofwatersupplytothefoodsub-system χ Unitwaterdemandperunitofelectricityproductionbypowerconversionplantj(bbl/GWh) j φ Lossfactorofwatersupplytothepowerconversionplantj j θ Average efficiency factor for CO emission abatement by power conversion plant j in time j,t 2 periodt 3.1. ObjectiveFunctions Thefirstobjectiveistominimizetotaleconomiccost,includingcostsofenergysupply forelectricityproduction,electricityconversioncosts,costsofwatersupply,costsoffood production,andcostsofCO emissionabatement. Thetotalsumofallcostsisdepicted 2 in(1). Water2021,13,121 7of27 J T T J T T (cid:18) (cid:93) (cid:93)(cid:19) MinO1 =∑ ∑esj,t×e(cid:93)scj,t+ ∑ f(cid:102)cj+ ∑ ∑ xj,t×p(cid:103)cj,t+ ∑ gwtf ×cgwtf +swtf ×cswtf j=1t=1 t=1 j=1t=1 t=1 + ∑J ∑T (cid:16)gwte×c(cid:93)gwte+swte×c(cid:103)swte+rwej,t×c(cid:93)rwej,t(cid:17)+ ∑T fot×c(cid:103)fot (1) j=1t=1 t=1 J T + ∑ ∑ xj,t×c(cid:93)eaj,t×c(cid:103)cj,t+ fot×c(cid:103)fat× f(cid:102)ft j=1t=1 ThesecondobjectivefunctionrepresentstheminimizationofCO emissionproduced 2 duringtheelectricityconversionandfoodproduction,respectively. Thus,theminimization ofnetCO emissionispresentedin(2). 2 J T (cid:16) (cid:17) ∑ ∑ MinO2 = θj,t×c(cid:103)cj,t+ f(cid:102)ft (2) j=1t=1 3.2. Constraints Theconstraint(3)representsthattheproduced-electricitybyeachpowerconversion plantineachtimeperiodmustnotbegreaterthantheenergy-supplyconversionquantity. xjt× f(cid:103)ej,t ≤ esj,t ∀j,t (3) Theconstraint(4)ensuresthatthedeliveredfossilfuelssuchascoalandnaturalgas mustbelessthantheirmaximumavailablequantityoverthetimeperiods. es ≤ av ∀j,t (4) j,t (cid:103)j,t Theconstraint(5)representsthatthesuppliedenergyforfoodproductionmustbe lessthanitsmaximumpermissibleelectricitysupplyineachtimeperiod. fo ×erf ≤ aerf ∀j,t (5) t (cid:101)t (cid:102)t,max Theconstraint(6)ensuresthattherequiredquantityofelectricityforwatercollection, treatmentandsupplypurposemustbelessthanitsmaximumallocatedamount. (cid:32) (cid:33) J (cid:16) (cid:17) erw× gwf +swf + ∑ gwe +swe +rwe ≤ aerw ∀j,t (6) (cid:101)t t t j,t j,t j,t (cid:102)t,max j=1 Theconstraint(7)ensuresthattheproducedelectricityfrompowerconversionplants mustmeetthesocio-economicdemandsofelectricityafterdeliveringforfoodproduction andwatercollection,treatmentandsupplypurpose. (cid:32) (cid:33) ∑J xj,t−e(cid:101)rtf × fot−e(cid:101)rwt × gwtf +swtf + ∑J (cid:16)gwej,t+swej,t+rwej,t(cid:17) ≥ d(cid:101)eet ∀j,t (7) j=1 j=1 Theconstraint(8)representsthatnetwatersupplyfromallsourcesmustmeetthe waterdemandforthefoodproductionineachtimeperiod. (cid:16) (cid:17) (1−δ)× gwtf +swtf ≥ fot×w(cid:102)ft ∀j,t (8) Theconstraint(9)representsthatnetwatersupplyfromallsourcesmustmeetthe waterrequirementforelectricityproduction. (cid:0)1−φ (cid:1)×(cid:16)gwe +swe +rwe (cid:17) ≥ χ ×x ∀j,t (9) j j,t j,t j,t j j,t Water2021,13,121 8of27 Theconstraint(10)ensuresthatthedeliverdgroundwaterquantitymustbelessthan orequalstothemaximumavailablegroundwaterquantityineachtimeperiods. J gwf + ∑gwe ≤ sy ∀j,t (10) t j,t (cid:102)t j=1 Theconstraint(11)ensuresthatthesuppliedsurfacewaterquantitymustbelessthan orequalstothemaximumavailablesurfacewaterquantityineachtimeperiods. J swf + ∑swe ≤ asw ∀j,t (11) t j,t (cid:103)t j=1 Theconstraint(12)ensuresthatthedeliverdrecycledwaterquantitymustbelessthan orequalstothemaximumavailablerecycledwaterquantityineachtimeperiods. J ∑rwe ≤ arw ∀j,t (12) j,t (cid:103)t j=1 The constraint (13) ensures that the produced food must meet the socio-economic demandforfood. fo ≥ d(cid:102)ef ∀j,t (13) t t The constraint (14) ensures that the produced CO quantity must be less than the 2 maximumpermissibleCO emissionsduringthetimeperiods. 2 J T T ∑ ∑ (cid:0) (cid:1) ∑ (cid:93) xj,t×c(cid:103)cj,t 1−θj,t + fot×(cid:102)fft ≤ tmcc ∀j,t (14) j=1t=1 t=1 Theconstraint(15)depictsthenon-negativityrestrictionsoverallthedecisionvariables. es ,x ,gwf,swf,gwe ,swe ,rwe , fo ≥0 ∀j,t (15) j,t j,t t t j,t j,t j,t t where (·) representtheintuitionisticfuzzyparametersinvolvedintheEFWSoptimiza- (cid:101) tionmodel. Allthediscussedmultiobjectiveoptimizationmethodsinthesupplementarymaterials arebasedonfuzzydecisionsettheory. Inthefuzzyoptimizationtechnique,eachobjective function’smembershipfunctionsaremaximizedtoachievetheoptimalglobalsolution. Sometimes,theneutralthoughtsorindeterminacydegreeinevitablyexistswhilemaking decisions. Thefuzzysetcannotbeappliedtotackletheneutralideasduetotheabsenceof anindeterminacydegree. Hencefuzzyprogrammingisalsonotapplicableforthiscase. Thebetterrepresentativeofsuchanindeterminatesituationcanbehandledbyneutrosophic decisionsettheoryefficiently. Thus,theproposedINPAcontemplatesdifferentaspects ofeachobjectives’marginalevaluationsbyhavingthetruth,indeterminacy,andafalsity degreeatatime. Thein-depthuncertaintyquantificationtechniqueunderneutrosophicset theorymakesitmorepowerfulandpromisinginyieldingabettersolutionthanthefuzzy settheory. 3.2.1. ProposedInterativeNeutrosophicProgrammingApproach(INPA) The real-life complexity most often creates the indeterminacy situation or neutral thoughtswhilemakingoptimaldecisions. Apartfromtheacceptanceandrejectionde- greesinthedecision-makingprocess,theindeterminacydegreealsohasmuchimportance. Thustocovertheneutralthoughtsorindeterminacydegreeoftheelementintothefeasible solutionset,Smarandache[29]investigatedaneutrosophicset. Thename“neutrosophic” istheadvancecombinationoftwoexplicitterms,namely;“neutre”extractedfromFrench Water2021,13,121 9of27 means,neutral,and“sophia”adoptedfromGreekmeans,skill/wisdom,thatunanimously providethedefinition“knowledgeofneutralthoughts”(seeSmarandache[29],Ahmadand Adhami[30],Ahmadetal.[31],AdhamiandAhmad[32]). TheNSconsidersthreesorts ofmembershipfunctions,suchastruth(degreeofbelongingness),indeterminacy(degree ofbelongingnessuptosomeextent),andafalsity(degreeofnon-belongingness)degrees into the feasible solution set. The idea of independent, neutral thoughts differs from the NS with all the uncertain decision sets such as FS and IFS. The updated literature worksolelyhighlightsthatmanypractitionersorresearchershavetakenthedeepinter- estintheneutrosophicresearchfield(see, AhmadandAdhami[33], Ahmadetal.[34], Ahmadetal.[5]). TheNSresearchdomainwouldgetexposureinthefutureandassistin dealingwithindeterminacyorneutralthoughtsinthedecision-makingprocess. Thisstudy also fetches the novel ideas of neutrosophic optimization techniques based on the NS. Anovelinteractiveneutrosophicprogrammingapproachisdevelopedtosolvethemulti- objectiveEFWSmodelunderintuitionisticfuzzyparameters. Themarginalevaluationof eachobjectivefunctionisquantifiedbythetruth,indeterminacy,andfalsitymembership functionsundertheneutrosophicdecisionset. Thus,NSplaysavitalroleinoptimizing multiobjective optimization problems by incorporating, executing, and implementing neutralthoughts. Definition 1. Ahmad et al. [5] Let there be a universal discourse Y such that y ∈ Y, then a neutrosophicset AinYcanbedepictedbytruthµ (y),indeterminacyσ (y)andafalsityν (y) A A A membershipfunctionsinthefollowingform: A = {< y, µ (y), σ (y), ν (y) > |y ∈Y} A A A where µ (y), σ (y) and ν (y) are real standard or non-standard subsets belong to ]0−,1+[, A A A alsogivenas,µ (y) :Y →]0−,1+[,σ (y) :Y →]0−,1+[,andν (y) :Y →]0−,1+[. Thereis A A A norestrictiononthesumofµ (y), σ (y)andν (y),sowehave A A A 0− ≤ supµ (y)+σ (y)+ supν (y) ≤3+ A A A BellmanandZadeh[35]firstpropoundedtheideaofafuzzydecisionset. Afterthat, itiswidelyadoptedbymanyresearchers. Thefuzzydecisionconceptcomprisesfuzzy decision(D),fuzzygoal(G),andfuzzyconstraints(C),respectively.Herewerecallthemost extensivelyusedfuzzydecisionsetwiththeaidofthefollowingmathematicalexpressions: D =O∩C Consequently,wealsodepicttheneutrosophicdecisionsetD ,whichcontemplate N overneutrosophicobjectivesandconstraintsasfollows: D = (∩K O )(∩I C) = (x, µ (x), σ (x), ν (x)) N k=1 k i=1 i D D D where (cid:26) (cid:27) µ (x),µ (x),...,µ (x) µ (x) = min O1 O2 Ok ∀ x ∈ X D µ (x),µ (x),...,µ (x) C1 C2 Ci (cid:26) (cid:27) σ (x),σ (x),...,σ (x) σ (x) = max O1 O2 Ok ∀ x ∈ X D σ (x),σ (x),...,σ (x) C1 C2 Ci (cid:26) (cid:27) ν (x),ν (x),...,ν (x) ν (x) = max O1 O2 Ok ∀ x ∈ X D ν (x),ν (x),...,ν (x) C1 C2 Ci where µ (x),σ (x) and ν (x) are the truth, indeterminacy and a falsity membership D D D functionsofneutrosophicdecisionsetD respectively. N Water2021,13,121 10of27 Theboundsfork-thobjectivefunctionundertheneutrosophicenvironmentcanbe obtainedasfollows: Uµ =U , Lµ = L fortruthmembership k k k k Uσ = Lµ+s , Lσ = Lµ forindeterminacymembership k k k k k Uν =Uµ, Lν = Lµ+t for falsitymembership k k k k k wheres andt ∈ (0,1)arepredeterminedrealnumbersprescribedbydecision-makers. k k The linear-type truth µ (O (x)), indeterminacy σ (O (x)) and a falsity ν (O (x)) k k k k k k membershipfunctionsunderneutrosophicenvironmentcanbefurnishedasfollows: µ (O (x)) = 1Ukµ−Ok(x) iiff OLµk(≤x)O≤(Lxµk) ≤Uµ (16) k k 0Ukµ−Lµk if Ok(x) ≥k Uµ k k k 1 if O (x) ≤ Lσ σ (O (x)) = Ukσ−Ok(x) if Lσk≤O (xk) ≤Uσ (17) k k Uσ−Lσ k k k 0 k k if O (x) ≥Uσ k k 0 if O (x) ≤ Lν ν (O (x)) = Ok(x)−Lνk if Lνk≤O (xk) ≤Uν (18) k k Uν−Lν k k k 1 k k if O (x) ≥Uν k k IfforanymembershipL =U ,thenthevalueofthesemembershipwillbeequalto1. k k IntroducingtheideaofBellmanandZadeh[35],wemaximizetheoverallachievement functiontoreachtheoptimalsolutionofeachobjectives. Themathematicalexpressionfor achievementfunctionisdefinedasfollows: Max mink=1,2,3,...,K µk(Ok(x)) Min maxk=1,2,3,...,K σk(Ok(x)) Min maxk=1,2,3,...,K νk(Ok(x)) (19) subjectto alltheconstraintsof(24) Also,assumethatµ (O (x)) ≥ α,σ (O (x)) ≤ βandν (O (x)) ≤ γ,forallk. k k k k k k Withtheaidofauxiliaryparametersα, βandγ,theproblem(19)canbetransformed intothefollowingproblem(20): (INPA) Maxψ(x) = η(α−β−γ)+(1−η)∑K (µ (O (x))−σ (O (x))−ν (O (x))) k=1 k k k k k k subjectto µ (O (x)) ≥ α, k k σ (O (x)) ≤ β, k k (20) ν (O (x)) ≤ γ, k k α ≥ β, 0≤ α+β+γ ≤3, α,β,γ ∈ [0,1] alltheconstraintsof(24) where η is the compensation co-efficient between the overall satisfaction level and the sumofindividualmarginalevaluationofeachobjectivefunctioninneutrosophicenvi- ronment. Thus,thedevelopmentofproposedINPA(20)hasanewachievementfunction whichisrepresentedbyaconvexcombinationofdifferencesamongtheboundsfortruth, indeterminacy,andfalsitydegreesofobjectivefunction(α−β−γ),andthesumofdif- ferencesamongtheseachievementdegrees(µ (O (x))−σ (O (x))−ν (O (x)))tomake k k k k k k suregeneratinganestablishedbalancedcompromisesolution.