UASB反应器处理垃圾渗滤液过程中的H2S去除英文华佳

JournalofSoutheastUniversity(EnglishEdition)　Vol.26,No.1,pp.91-95Mar.2010　ISSN1003—7985H2SremovalinlandfillleachatetreatmentusingUASBreactorHuaJia1　ZhangLinsheng1　PanYanli2　LiYuezhong2(1SchoolofEnergyandEnvironment,SoutheastUniversity,Nanjing210096,China)(2WehrleEnvironmentalTechnologyCo.,Ltd.,Changzhou213022,China)Abstract:LeachatefromasanitarylandfillsiteinChengdu,Chinaistreatedusingahybrid-UASBreactoratpilotscale.H2S,resultingfromtheanaerobicbioconversionprocessofsulfate-reducingbacteria(SRB),inhibitsthegrowthandactivityofmethane-producingbacteria(MPB)andposesseriousproblemsofpollution,soFeCl3isusedforH2Sremoval.Theresultsshowthatthesystemperformswellinthetreatmentprocess.CODremovalgenerallyincreaseswiththeincreaseintheorganicloadingrate(OLR),whilethesulfateremovaldecreasesslowly.AstheOLRishigherthan7kgCOD/(m3·d),bothCODandsulfateremovaltendtobestable.Whenthereactorisoperatedatthedesignloadof9kgCOD/(m3·d),CODandsulfateremovalremainabout79%and91%,respectively.Atthesametime,thepercentageofCODremovedbySRB(CODSRB)alsodecreasesfrom8.9%to4.0%.WithFeCl3addition,CODremovalincreasesto83%,whilesulfateremovalandCODSRBfurtherdecreaseto89%and1.89%,respectively.Accordingtothemassbalance,nearly82%ofthesulfurispreventedfromconvertingintoH2S.Moreover,whentheFeCl3dosageismorethan1.6g/Lleachate,H2Scanberemovedtotallyfromthebiogas.Therefore,theapplicationofFeCl3forH2SremovalinleachatetreatmentusingtheUASBreactorisverysuitableandviable.Keywords:landfillleachate;upflowanaerobicsludgeblanket(UASB);H2S;FeCl3;sulfurbalanceReceived2009-09-10.Biographies:HuaJia(1970—),male,graduate;ZhangLinsheng(corre-spondingauthor),male,professor,[e-mail]:HuaJia,ZhangLinsheng,PanYanli,etal.H2SremovalinlandfillleachatetreatmentusingUASBreactor[J].JournalofSoutheastUniversity(EnglishEdition),2010,26(1):91-95.Asamixtureoforganicandinorganiccompounds,aswellasamixtureofpathogenicmicroorganisms,landfillleachatehasahazardousimpactontheenvironmentandhu-manhealth.Thoughmanytreatmentprocesseshavebeenadoptedtocontrolthepollutioncausedbyleachate,acombi-nationofphysical,chemicalandbiologicalmethodshasbeengainingawiderpopularity.Thebiologicaltreatmentmethod,especiallytheanaerobictechnology,ismainlythefirststageinanintegratedprocess.Amongothers,theupflowanaerobicsludgeblanket(UASB)reactorisregardedasoneofthemostsuccessfulandextensivelyappliedsystemsduetoitshightreatmentefficiencyandshorthydraulicretentiontime(HRT)[1].　However,themajorproblemoftheanaerobictechnologyistheconspicuousendproducthydrogensulfide(H2S)whenthereissulfateintheinfluent.Microbialsulfatereductionisaconventionalmethodofanaerobicdigestion.Duringtheoxi-dationoforganicmatter,specificbacteriausingsulfateastheterminalelectronacceptorproducesH2Sasthefinalproduct,whichcanbedescribedas[2]SO2-4+nutrients+H2O※H2S+HCO-3(1)Thisprocessisknownasthedissimilatorysulfatereductionandthebacteriainvolvedareknownassulfate-reducingbacteria(SRB).Simplesubstrates,suchashydrogen,lactate,ethanol,acetate,methanolandpropionate,areoftenusedaselectrondonors[3],andcomplexsubstrates,suchascellulose,starchandmolasses,canalsobeused[4].Notonlydoestheendproduct(H2S)inhibitthegrowthandactivityofmethane-producingbacteria(MPB),butitposesseriousproblemsofodor,toxicityandcorro-sion.SomeplantsandprojectsusingbiogasasbioenergyhavebeenshutdownduetothecorrosionproblemofH2S[5].Furthermore,whenburningwithCH4,H2Sex-haustsintheformofSO2,whichismoredangerousthanH2Sbecauseofitsdetrimentalroleintheatmosphere.Therefore,itisnecessarytoremoveH2Spriortoitsuseforthesakeofsafety,healthandtheenvironment.　H2Scanberemovedthroughaphysicalorachemicalmethodsuchastheabsorptionandoxidationprocess[6].TheuseofironspeciesforH2Sremovalisacommonandextensivelydocumentedpractice[7-8],andtheFeCl3solu-tionhasbeenusedtoremoveH2Sindairymanuretreat-ment[9].ThemainadvantagesofironprecipitationforH2Sre-movalincludehighremovalefficiency,lowsludgegenerationandnontoxicproductformation[10].Duringthetreatmentprocess,H2Sisabsorbedandoxidizedtoelementalsulfur(S0),andsimultaneouslyFe3+isreducedtoFe2+andprecip-itatedintermsofFeS.Inaddition,partoftheH2Scanalsobeprecipitatedwithheavymetalsinwastewater,whichcanbeillustratedby2FeCl3+3H2S※2FeS+S+6HCl(2)H2S+M2+※MS+2H+(3)whereM2+representsdivalentmetalliccationssuchasPb2+.　However,therearefewstudieswhichhaveevaluatedtheprocessperformanceandbehaviorsoftheUASBreactorwhenFeCl3isusedforH2Sremovalinlandfillleachatetreatment.Basedonthisbackground,thispaperisconductedtotestH2SremovalwithFeCl3additionsonapilotscale.Aspecificfocusispaidtoevaluatetheperformanceofthehybrid-UASBreactor,removalefficiencyoftheH2Sandsulfurbalancedur-ingtheprocessofleachatetreatment.1　MaterialsandMethods1.1　Leachateanalysis　ThelandfillleachateusedinthispaperiscollectedfromtheChangansanitarylandfillsite,locatedinChengdu,Chi-na.ThemainphysicochemicalcharacteristicsoftheleachateareshowninTab.1.Tab.1　CharacteristicsofinfluentleachateParameterMeanRangepH7.66.7to8.5COD/(mg·L-1)1830011850to24870BOD5/(mg·L-1)68105270to8350BOD/COD0.390.34to0.44SS/(mg·