稻草和污水污泥产氢

Hydrogenproductionbyanaerobicco-digestionofricestrawandsewagesludgeMijungKima,YingnanYanga,*,MarinoS.Morikawa-Sakuraa,QinghongWanga,MichaelV.Leeb,Dong-YeolLeec,ChuanpingFengd,YulinZhoua,ZhenyaZhangaaGraduateSchoolofLifeandEnvironmentalSciences,UniversityofTsukuba,Tsukuba,Ibaraki305-8577,JapanbWorldPremierInternational(WPI)ResearchCenterforMaterialsNanoarchitectonics(MANA),NationalInstituteforMaterialsScience(NIMS),1-1Namiki,Tsukuba,Ibaraki305-0044,JapancEnvironmentalTechnologyTeam,GSEngineering&Construction,Namdaemun-Ro5-Ga,Joong-Gu,Seoul100-722,KoreadWaterResourceandEnvironmentalEngineering,ChinaUniversityofGeosciences,No.29XueyuanRoad,Beijing100083,ChinaarticleinfoArticlehistory:Received22June2011Receivedinrevisedform19October2011Accepted22October2011Availableonline7December2011Keywords:RicestrawSewagesludgeAnaerobicco-digestionBiohydrogenproductionC/NratioabstractInthisstudy,therichcarboncontentofricestrawandthehighnitrogencontentofsewagesludgemakethestrawagoodpotentialsubstrateandthesludgeaviableinoculumforbiohydrogenproduction.Twotreatmentconditionsforthesewagesludge(rawandheat-treated)wereusedinthepresentexperiments.Batchtestusingamixtureofricestrawandsewagesludgewerecarriedouttoinvestigatetheoptimumcarbontonitrogen(C/N)ratioforeffectivebiohydrogenproduction.Theexperimentalresultsindicatethatuntreatedsludgecouldbeusedastheinoculumforefficienthydrogenproductionwhenmixedwiththeappropriateproportionofricestraw.Accordingtoourresults,biogasandhydrogenproductioninallrawsludgecasesrampedupmorequicklyandalsoexhibitedlongerandhigherhydrogenproductionincomparisonwithheat-treatedcases.AttheC/Nratioof25inuntreatedsludge,hydrogenproductionwas33%higherthanheat-treatedone.Additionally,underthesameconditions,highandstablehydrogencontent(58%)andthemaximalhydrogenyield(0.74mmolH2/g-VSaddedstraw)wereobtained.Copyrightª2011,HydrogenEnergyPublications,LLC.PublishedbyElsevierLtd.Allrightsreserved.1.IntroductionRecently,biohydrogenhasbeenattractingincreasingattentionasabiofuelofthefuturebecausebiohydrogentechnologynotonlyconstitutesabiofuelsource,butalsocanbeappliedinthedisposalofvariousenvironmentalpollutants,forinstance,sewagesludge,industrialoragriculturewaste,andurbansolidwaste[1,2].Lignocellulosicmaterialshaveahighpolysaccharidecontent(about60%)containingthreekeystructuralcompo-nents:cellulose,hemicellulose,andlignin[3,4].Also,lignocel-lulosicmaterialusedtoproducebiofuelsdoesnotcompetewithgrain.Inparticular,ricestrawisoneofthemostabundantagriculturalwastesinJapan(9milliontonsin2006),withonlyasmallquantityofricestrawbeingusedforlivestockfeedstufforfertilizer.Themajorityofthewasteisplowedintothefield,andsomeisburnedinopenfields,causingairpollution[5].Biofuels(ethanolandhydrogen)fromlignocellulosicmaterials,suchasbarleystraw,wheatstraw,ricestraw,orcornstalks,areaneconomicallyavailablerenewableformofenergy.Previously,Komatsuetal.[6]investigatedthefeasi-bilityofanaerobicco-digestionofricestraw,pretreatedwithwaterandenzymes,andsewagesludgeforbiogasproduction.*Correspondingauthor.Tel.:þ81298538830;fax:þ81298534922.E-mailaddress:[e-mail](Y.Yang).Availableonlineat(2012)3142e31490360-3199/$eseefrontmatterCopyrightª2011,HydrogenEnergyPublications,LLC.PublishedbyElsevierLtd.Allrightsreserved.doi:10.1016/j.ijhydene.2011.10.116Chengetal.[7]reportedthefeasibilityofhydrogenproductionfromlignocellulosicmaterialsasasubstrateusingcultivatedmixedorpurehydrogen-producingbacteria.Nguyenetal.[4]reportedusingahyperthermophilicbacteriumThermotoganeapolitanaat75Cforfivedaystoproducebiohydrogenfromuntreatedricestrawandfromricestrawpretreatedwithammoniaand/orsulfuricacid.However,scalingupabiore-actorforonlypurehydrogen-producingbacteriaisimpracticalduetothesizableexpenditurenecessaryforgrowthandcultivationofthestrain.Hence,practicalbiologicalhydrogenproductionrequirestheeliminationoftheabovepretreat-mentsforbothsubstrateandinoculumwhilestillmaintaininghighyields.Untilnow,technologiesusefulforcommercial-izingbiohydrogenproductionhavenotyetbeenclearlydefined.Therefore,basicresearchiscriticalinordertoadvancethedevelopmentoftechnologiesusefulforcommercializingbiohydrogenproduction.Accordingtopreviousresearch,somehydrogen-producingbacteriaoftheClostridiumspecieswerereportedtodegradeinsolublecelluloseandcellulosicwastematerialswithoutanychemicalpretreatment[8,9].Inaddition,Uenoetal.[10]demonstratedalackofdetectablemethaneinthebiogasfromcellulosebynaturalanaerobicmicroflora.Weareinter-estedinusingricestrawdirectlywithrawsewagesludgeinordertoreducetheenergyinputandachievecost-effectivehydrogenproduction.Inanaerobicbiologicalprocesses,propercarbontonitrogen(C/N)ratioisimportantforefficientdigestion.Previously,HillsandRoberts[11]demonstratedthattheproperC/Nratioforanaerobicdigestionwas25e30fromlignocellulosicmaterials(C/Nratioof35e118)mixedwithdairymanure(C/Nratioofaround12).Generally,organicwastewithhighnitrogencontentcombinedwithlignocellu-lo