acombinedsystemofmicrobialfuelcellandmembranebiore

Performanceofacombinedsystemofmicrobialfuelcellandmembranebioreactor:Wastewatertreatment,sludgereduction,energyrecoveryandmembranefoulingXinyingSub,YuTiana,b,n,ZhicaiSunc,YaobinLub,ZhipengLibaStateKeyLaboratoryofUrbanWaterResourceandEnvironment,HarbinInstituteofTechnology(SKLUWRE,HIT),Harbin150090,ChinabSchoolofMunicipalandEnvironmentalEngineering,HarbinInstituteofTechnology,Harbin150090,ChinacDaqingWaterGroupCompanyLimited,Daqing163311,ChinaarticleinfoArticlehistory:Received25February2013Receivedinrevisedform2April2013Accepted4April2013Availableonline18April2013Keywords:Membranebioreactor(MBR)Microbialfuelcell(MFC)MembranefoulingLooselyboundEPS(LB-EPS)EnergyrecoveryabstractAnovelcombinedsystemofsludgemicrobialfuelcell(S-MFC)stackandmembranebioreactor(MBR)wasproposedinthisstudy.Thenon-consumedsludgeintheMBRsludge-fedS-MFCwasrecycledtotheMBR.Inthecombinedsystem,theCODandammoniatreatmentefficienciesweremorethan90%andthesludgereductionwas5.1%higherthanthatoftheconventionalMBR.It'sworthnotingthattheenergyrecoveryandfoulingmitigationwereobservedinthecombinedsystem.InthesingleS-MFC,about75mgL−1CODcouldbetranslatedtoelectricityduringonecycle.TheaveragevoltageandmaximumpowerproductionofthesingleS-MFCwere430mVand51mWm−2,respectively.Additionally,thecombinedsystemwasabletomitigatemembranefoulingbythesludgemodification.Exceptforthecontentdecrease(22%),S-MFCdestroyedsimplearomaticproteinsandtryptophanprotein-likesubstancesinlooselyboundextracellularpolymericsubstances(LB-EPS).Theseresultsindicatedthateffectivewastewatertreatment,sludgereduction,energyrecoveryandmembranefoulingmitigationcouldbeobtainedinthecombinedsystem.&2013ElsevierB.V.Allrightsreserved.1.IntroductionAsefficienttechnologyforwastewatertreatment,membranebioreactors(MBRs)haveexperiencedunprecedentedgrowthinrecentyears(FanandZhou,2007).MBRsofferseveraladvantagesoverconventionalactivatedsludgesystem,includingstableandhigheffluentquality,easeofoperation,smallfootprint,andabsoluteremovalofbacteria(Wangetal.,2009b).However,membranefoulingremainsasamajorobstacleforwiderapplicationofMBRs(Kimuraetal.,2012).Themostcommonapproachestoreducemembranefoulingaresupplyinganexcessiveamountofair(highenergycon-sumption),cleaningthemembranemodule(reductionthemem-branelife-span),optimizingtheoperatingparametersandimprovingactivatedsludgecharacteristicsinthereactor(Akamatsuetal.,2010;Bani-MelhemandElektorowicz,2010).Microbialfuelcells(MFCs)havebeendevelopedasapromisingtechnologytorecoverenergyfromwastewater,marinesediments,sludgeetc.(Minetal.,2005).SeveralsystemscombiningMBRandMFChavebeenreportedpreviously.Abioelectrochemicalmembranereactor,whichtakesadvantageofbothMBRandMFCprocesses,wasrecentlydeveloped(Wangetal.,2011).Inthisreactor,stainlesssteelmeshwasdesignedasboththecathodeandthemembrane.Wangetal.,2012developedamorepracticalMFC–MBRintegratedprocess,whichusedtheaerationMBRtankasthecathodechamberandthecarbonfeltasthecathode.BothsystemstookMFCsaswastewatertreatmentunitsforsimultaneouslyenhancingwastewatertreatmentandachievingenergyrecovery.However,forMBRprocess,stableandhigheffluentqualityisoneoftheadvantages(98%totalorganiccarbonremovaland99%ammoniaremoval),whilemembranefoulingisamajorobstacle(Panetal.,2010;Visvanathanetal.,2000).ItwouldbeexcitingifacombinedMBR–MFCsystemofferstheoptionofmembranefoulingmitigation.Ithasbeenreportedthatsludgeextracellularpolymericsubstances(EPS),whichhavebeenconsideredasthemajorcauseofmembranefoulinginMBRs(Changetal.,2001;Drewsetal.,2006),couldberemovedby36.8%intheformofdissolvedorganiccarbon(DOC)afterMFCtreatment(Jiangetal.,2010).Therefore,takingMFCasasludgetreatmentunitmighthavebenefitsformembranefoulingmitigationduetoEPSreductionandmodificationofsludgecharacteristics.AnovelcombinedsystemofMBRandMFCwasestablishedinthisstudy.TheMFCwasoperatedwithadirectfeedofactivatedsludgefromtheMBR.Thenthenon-consumedsludgeintheMFCwasreturnedtotheMBR.MFCcouldconvertthechemicalenergyinorganicmatterdirectlyintousefulelectricalenergybythecatalyticreactionofmicroorganisms;ontheotherhand,thesludgeishydrolyzed,convertedandreducedduringelectricityproductionofMFCs(Xiaoetal.,2011).25.1%reductionintotalsuspendedsolidsContentslistsavailableatSciVerseScienceDirectjournalhomepage:://dx.doi.org/10.1016/j.bios.2013.04.005nCorrespondingauthorat:StateKeyLaboratoryofUrbanWaterResourceandEnvironment,HarbinInstituteofTechnology(SKLUWRE,HIT),Harbin150090,China.Tel./fax:[phone].E-mailaddress:[e-mail](Y.Tian).BiosensorsandBioelectronics49(2013)92–98(TSS)and22.8%reductioninvolatilesuspendedsolids(VSS)wereobservedintheMFCwhichusedsewagesludgeasfuel(Xiaoetal.,2011).Consequently,thecombinedsystemmayalsohavethepotentialforbothenergyrecoveryandsludgereduction.Therefore,theobjectiveofthisresearchwasundertakentoevaluatetheperformancesofthecombinationofMBRandMFC:(1)assesstheefficienciesofwastewatertreatmentandsludgereduc-tion;(2)calculatethepowergenerationandCOD