Performance-and-optimization-of-biological-nitrogen-removal-process-enhanced

BiochemicalEngineeringJournal43(2009)280–287ContentslistsavailableatScienceDirectBiochemicalEngineeringJournaljournalhomepage:www.elsevier.com/locate/bejPerformanceandoptimizationofbiologicalnitrogenremovalprocessenhancedbyanoxic/oxicstepfeedingGuibingZhua,b,YongzhenPengb,c,∗,LimingZhaib,d,YuWanga,ShuyingWangcaStateKeyLaboratoryofEnvironmentalAquaticChemistry,ResearchCenterforEco-EnvironmentalSciences,ChineseAcademyofSciences,Beijing,PRChinabSchoolofMunicipalandEnvironmentalEngineering,HarbinInstituteofTechnology,Harbin,PRChinacKeyLaboratoryofBeijingWaterQualityScienceandWaterEnvironmentRecoveryEngineering,BeijingUniversityofTechnology,Beijing,PRChinadDepartmentofCivilEngineering,HongKongUniversityofScienceandTechnology,ClearWaterBay,Kowloon,HongKongarticleinfoArticlehistory:Received21November2007Receivedinrevisedform6October2008Accepted18October2008Keywords:EnhancedbiologicalnitrogenremovalOptimizationBioreactorsBioprocessdesignStep-feedingprocessWastewatertreatmentabstractTheaimofthispaperistoinvestigatetheperformanceandoptimizationofanbiologicalnitrogenremovalprocessenhancedbytheanoxic/oxicfourstagesstep-feedingprocessundersufficient/insufficientinflu-entcarbonsource.Theconceptofinfluentflowdistributionratio(�)wasintroducedaccordingtotheperformanceofthestep-feedprocessforinflowsplittingandvolumedistribution.Undertheconditionofsufficientcarbon,theuniforminfluentflowdistributionratiowasproposedfromthestandpointofwhichiseasyforprocesscontrol,operationoptimizationandmanagement.UndertheconditionofdifferentinfluentC/Nratios,theoptimalinfluentflowdistributionratios(�opt)weredetermined,bytrial-and-errormethod.Theresultsshowedthatmorethan95.81%ofthetotalnitrogenremovalefficiencycouldbeachievedbystep-feedingprocesswithafixedinfluentC/Nratio.Amodelwasintroducedtoderivetherelationshipsoftotalnitrogenremovalefficiencywith�andinfluentC/Nratio.Whentheinfluentcar-bonsourcewasinsufficient,however,the�optbetweentwoadjacentstagesshouldnotbeuniform.Theresultsalsoshowedthatthefour-st