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1、废水处理工艺设计及计算第11章6&8节211-6Surfacefiltration表面过滤FiltrationMechanism(机理)SurfacefiltrationDepthfiltrationSurfacefiltration,arelativelynewtechnology,involvesasievingactionsimilartoakitchencolander.Surfacefiltrationisusedtoremovetheresidualsuspendedsolidsfromsecondaryeffluentsand
2、stabilizationpondeffluents,andasanalternativetodepthfiltration.Depthfiltrationwasdevelopedoriginallyforthetreatmentofsurfacewaterforpotableusesandlateradaptedforwastewatertreatmentapplications.Depthfiltrationisusedintoachievesupplementalremovalofsuspendedsolids(includingpa
3、rticulateBOD)fromwastewatereffluentsforthefollowingpurposes:toallowmoreeffectivedisinfection;asapretreatmentstepforsubsequenttreatmentstepssuchascarbonadsorption,membranefiltration,oradvancedoxidation;toremovechemicallyprecipitatedphosphorus.Definition3Surfacefiltrationisg
4、aininginpopularitybecauseofthe(1)highqualityeffluentproduced,(2)smallerfootprint,(3)lowbackwashrates,(4)reducedmaintenancerequirements.Surfacefiltrationhasbeenusedinseveralapplicationsincluding:asareplacementfordepthfiltrationtoremoveresidualsuspendedsolidsfromsecondaryeff
5、luents,fortheremovalofsuspendedsolidsandalgaefromstabilizationpondeffluents,asapretreatmentoperationbeforemicrofiltrationorUVdisinfection.4AvailableFiltrationTechnologiesTheCMF,marketedunderthetrademarkAquaDisk®byAqua-AerobicSystems,alsoconsistsofseveraldisksmountedvertica
6、llyinatank.Eachdiskiscomprisedofsixequalsegments.Operationally,waterflowsbygravityfromtheexteriorofthedisksthroughthefiltermediumtoaninternalcollectionsystem.Typically,twotypesoffilterclothareused:aneedlefeltclothmadeofpolyesterorsyntheticpilefabriccloth.Avacuumsystemis.Va
7、cuumsuctionheads,locatedoneithersideofthedisk,areusedtoremovetheaccumulatedsolidsbydrawingfiltratewaterfromthefiltrateheaderbackthroughtheclothmediawhilethediskisrotating.5TheDCMF,marketedunderthetrademarkAquaDisk®byAqua-AerobicSystems,consistsofclothfilterelements,whichha
8、veadiamondshapedcrosssection.Thefilterelementsarecleanedbyavacuumsweepwhichmovesbackandfo
