氨氧化季节变化特性

Anaerobicammoniumoxidation(anammox)underrealisticseasonaltemperaturevariations:CharacteristicsofbiogranulesandprocessperformanceQiongGuo,Bao-ShanXing,PengLi,Jia-LiXu,Chen-ChenYang,Ren-CunJin⇑DepartmentofEnvironmentalScienceandEngineering,HangzhouNormalUniversity,Hangzhou310036,ChinaKeyLaboratoryofHangzhouCityforEcosystemProtectionandRestoration,HangzhouNormalUniversity,Hangzhou310036,ChinahighlightsTheanammoxperformancewasgreatlyaffectedbyrealisticseasonaltemperatures.Thereactorunderwentalongprocessofrecoveryfrompsychrophilicstress.Thepropertiesoftheanammoxgranuleschangedwithtemperaturefluctuation.Thelinksbetweenanammoxperformanceandsludgecharacteristicswererevealed.articleinfoArticlehistory:Received18May2015Receivedinrevisedform8June2015Accepted9June2015Availableonline16June2015Keywords:AnammoxGranularsludgeNitrogenremovalSeasonaltemperaturechangeabstractInthisstudy,theeffectsofrealisticseasonaltemperaturesonthenitrogenremovalperformanceofanaer-obicammoniumoxidation(anammox)andthepropertiesoftheanammoxgranuleswerecomparativelyinvestigatedfor330days.Theresultsdemonstratedthatthenitrogenremovalefficiency(NRE),nitrogenloadingrate(NLR)andnitrogenremovalrate(NRR)weredecreaseddramatically,asthetemperaturedecreasedfrom31.2to2.5C.However,thenitrogenremovalperformancerecoveredandanteasthetemperatureincreasedgradually.Afterlowtemperatureexposure,thesettleabilitytendedtoworsen,andgranulesappearedtobemoreirregularwithasmalleraveragegranulediameter,andtheextracellu-larpolymericsubstances(EPS)contentincreasedslightly,whilethespecificanammoxactivity(SAA)decreasedobviously.Thisrealisticseasonaltemperaturesbasedresearchwasanillationoftheactualoperation,andcouldbepotentiallyimplementedtomaintainstabilityfortheapplicationofanammoxtechnology.2015ElsevierLtd.Allrightsreserved.1.IntroductionAnaerobicammoniumoxidation(anammox)isarecentlydis-coverednovel,environmentallyfriendly,cost-effectiveprocessfornitrogenremovalfromwastewater(Tangetal.,2009;vanderStaretal.,2007).Anammoxbioreactorsaredesignedtotreatwastewatersatrelativelyhighwatertemperatures(exceeding25C)becausetheoptimumtemperaturefortheoperationoftheanammoxprocessisapproximately30–40C(Dostaetal.,2008;Huetal.,2013).However,thetemperatureofmunicipalwastewa-ter,black(toilet)waterandsomeindustrialwastewaterislowerandusuallyvariesseasonally.Therefore,themainchallengeforapplyinganammoxinthewaterlineofawastewatertreatmentplant(WWTP)istoachievestableoperationundertemperatureinstabilitydespitealoweranammoxgrowthrate(Lottietal.,2014).Althoughseveralstudieshavedemonstratedthattheanam-moxprocessstilloccursatlowertemperatures(Hendrickxetal.,2014;Huetal.,2013;Yuetal.,2013),astableanammoxprocesscouldnotbemaintainedattemperatureslowerthan5C.Notably,anammoxbacteriaremainabundantandactiveinsedi-mentsofthesouthernNorthSeainwinter(Baleetal.,2014).Usingmainstreamwastewater,theanammoxprocessenablesthedevelopmentofenergy-autarkicwastewatertreatmentplants(Lottietal.,2014).Therecentdevelopmentofmoreenergy-efficienttreatmentsformunicipalwastewaterandindus-trialwastewaterandsimplifiedoperationshasenabledstablenitrogenremovalperformanceunderpsychrophilicconditions,2015ElsevierLtd.Allrightsreserved.⇑Correspondingauthorat:DepartmentofEnvironmentalScienceandEngineer-ing,HangzhouNormalUniversity,Hangzhou310036,China.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](R.-C.Jin).BioresourceTechnology192(2015)765–773ContentslistsavailableatScienceDirectBioresourceTechnologyjournalhomepage:ficantstrategybyallowingprocessdesignfordifferentseasons,particu-larlywinterconditions.Thegranulecharacteristicsareimportantforthedesignandmonitoringofbioreactors.AccordingtoShengetal.(2010)andNietal.(2010),thecharacteristicsofgranules,suchassettlingvelocityandextracellularpolymericsubstances(EPS)content,playimportantrolesinthefaststart-upofgranule-basedprocesses.Thesignificantincreaseinsettlingvelocitiescontributestogreatbio-massaccumulationinthereactor,andtheEPShaveasignificantinfluenceonsomephysicochemicalpropertiesofthesludge.Thepermeability,sizedistribution,physicalstrength,andmicrobialactivityofgranulesarealsoofconsiderablesignificance(Gonzalez-Giletal.,2001).What’smore,becauseofthelowgrowthrateofanammoxbacteria,goodefficientbiomassretentioniscrit-icalforreactoroperationandismostlydeterminedbythecharac-teristicsofthegranularsludge,e.g.,theparticlesizedistribution,settlingvelocity,morphology,EPScontent,wetdensityandtheratioofdryweight/wetweight.Severalfactorsaffectinganaerobicgranulequalityhavebeenextensivelystudied(Tangetal.,2011;Xingetal.,2015).Forexample,boththesettlingvelocityandtheEPSareaffectedbyexternalconditionssuchasthepresenceofmultivalentmetalsortoxiccompounds(Nietal.,2010;Shengetal.,2010),andthediameterdistributionisdependenton(nitro-genloadingrate)NLRand(nitrogenremovalrate)NRR,whichexpresstheperformanceofanammoxreactor.However,littleresearchhasfoc