湿地里的anammox的研究Nitrate-Removal-in-Shallow--Open-Water-Treatment-Wetlands

NitrateRemovalinShallow,Open-WaterTreatmentWetlandsJustinT.Jasper,†,‡ZackaryL.Jones,†,§JonathanO.Sharp,†,§andDavidL.Sedlak*,†,‡†ReNUWItEngineeringResearchCenter‡DepartmentofCivil&EnvironmentalEngineering,UniversityofCaliforniaatBerkeleyBerkeley,California94720,UnitedStates§DepartmentofCivil&EnvironmentalEngineering,ColoradoSchoolofMines,Colorado80401,UnitedStates*SSupportingInformationABSTRACT:Thediffusebiomatformedonthebottomofshallow,open-waterunitprocesswetlandcellscontainssuboxiczonesthatprovideconditionsconducivetoNO3−removalviamicrobialdenitrification,aswellasanaerobicammoniumoxidation(anammox).Toassesstheseprocesses,nitrogencyclingwasevaluatedovera3-yearperiodinapilot-scalewetlandcellreceivingnitrifiedmunicipalwastewatereffluent.NO3−removalvariedseasonally,withapproximatelytwo-thirdsoftheNO3−enteringthecellremovedonanannualbasis.MicrocosmstudiesindicatedthatNO3−removalwasmainlyattributabletodenitrificationwithinthediffusebiomat(i.e.,80±20%),withaccretionofassimilatednitrogenaccountingforlessthan3%oftheNO3−removed.TheimportanceofdenitrificationtoNO3−removalwassupportedbythepresenceofdenitrifyinggenes(nirSandnirK)withinthebiomat.Whilemodestwhencomparedtothepresenceofdenitrifyinggenes,ahigherabundanceoftheanammox-specificgenehydrazinesynthase(hzs)atthebiomatbottomthanatthebiomatsurface,thesimultaneouspresenceofNH4+andNO3−withinthebiomat,andNH4+removalcoupledtoNO2−andNO3−removalinmicrocosmstudies,suggestedthatanammoxmayhavebeenresponsibleforsomeNO3−removal,followingreductionofNO3−toNO2−withinthebiomat.Theannualtemperature-correctedarealfirst-orderNO3−removalrate(k20=59.4±6.2myr−1)washigherthanvaluesreportedformorethan75%ofvegetatedwetlandsthattreatedwaterinwhichNO3−wastheprimarynitrogenspecies(e.g.,nitrifiedsecondarywastewatereffluentandagriculturalrunoff).Theinclusionofopen-watercells,originallydesignedfortheremovaloftraceorganiccontaminantsandpathogens,inunit-processwetlandsmayenhanceNO3−removalascomparedtoexistingvegetatedwetlandsystems.■INTRODUCTIONThedischar