污水处理给排水专业英文文献翻译

污水处理---给排水专业英文文献翻译SewagetreatmentAbstract：Sewagetreatment,ordomesticwastewatertreatment,istheprocessofremovingcontaminantsfromwastewaterandhouseholdsewage,bothrunoff(effluents)anddomestic.Itincludesphysical,chemical,andbiologicalprocessestoremovephysical,chemicalandbiologicalcontaminants.Itsobjectiveistoproduceawastestream(ortreatedeffluent)andasolidwasteorsludgesuitablefordischargeorreusebackintotheenvironment.Thismaterialisofteninadvertentlycontaminatedwithmanytoxicorganicandinorganiccompounds.Keywords:Sewagetreatment,fixed-filmandsuspended-growth,ActivatedsludgeOriginsofsewageSewageiscreatedbyresidences,institutions,andcommercialandindustrialestablishments.Rawinfluent(sewage)includeshouseholdwasteliquidfromtoilets,baths,showers,kitchens,sinks,andsoforththatisdisposedofviasewers.Inmanyareas,sewagealsoincludesliquidwastefromindustryandcommerce.Theseparationanddrainingofhouseholdwasteintogreywaterandblackwaterisbecomingmorecommoninthedevelopedworld,withgreywaterbeingpermittedtobeusedforwateringplantsorrecycledforflushingtoilets.Alotofsewagealsoincludessomesurfacewaterfromroofsorhard-standingareas.Municipalwastewaterthereforeincludesresidential,commercial,andindustrialliquidwastedischarges,andmayincludestormwaterrunoff.Sewagesystemscapableofhandlingstormwaterareknownascombinedsystemsorcombinedsewers.Suchsystemsareusuallyavoidedsincetheycomplicateandtherebyreducetheefficiencyofsewagetreatmentplantsowingtotheirseasonality.Thevariabilityinflowalsoleadstooftenlargerthannecessary,andsubsequentlymoreexpensive,treatmentfacilities.Inaddition,heavystormsthatcontributemoreflowsthanthetreatmentplantcanhandlemayoverwhelmthesewagetreatmentsystem,causingaspilloroverflow.Itispreferabletohaveaseparatestormdrainsystemforstormwaterinareasthataredevelopedwithsewersystems.Asrainfallrunsoverthesurfaceofroofsandtheground,itmaypickupvariouscontaminantsincludingsoilparticlesandothersediment,heavymetals,organiccompounds,animalwaste,andoilandgrease.Somejurisdictionsrequirestormwatertoreceivesomeleveloftreatmentbeforebeingdischargeddirectlyintowaterways.Examplesoftreatmentprocessesusedforstormwaterincludesedimentationbasins,wetlands,buriedconcretevaultswithvariouskindsoffilters,andvortexseparators(toremovecoarsesolids).ProcessoverviewSewagecanbetreatedclosetowhereitiscreated(inseptictanks,biofiltersoraerobictreatmentsystems),orcollectedandtransportedviaanetworkofpipesandpumpstationstoamunicipaltreatmentplant(seesewerageandpipesandinfrastructure).Sewagecollectionandtreatmentistypicallysubjecttolocal,stateandfederalregulationsandstandards.Industrialsourcesofwastewateroftenrequirespecializedtreatmentprocesses(seeIndustrialwastewatertreatment).Conventionalsewagetreatmentmayinvolvethreestages,calledprimary,secondaryandtertiarytreatment.Primarytreatmentconsistsoftemporarilyholdingthesewageinaquiescentbasinwhereheavysolidscansettletothebottomwhileoil,greaseandlightersolidsfloattothesurface.Thesettledandfloatingmaterialsareremovedandtheremainingliquidmaybedischargedorsubjectedtosecondarytreatment.Secondarytreatmentremovesdissolvedandsuspendedbiologicalmatter.Secondarytreatmentistypicallyperformedbyindigenous,water-bornemicro-organismsinamanagedhabitat.Secondarytreatmentmayrequireaseparationprocesstoremovethemicro-organismsfromthetreatedwaterpriortodischargeortertiarytreatment.Tertiarytreatmentissometimesdefinedasanythingmorethanprimaryandsecondarytreatment.Treatedwaterissometimesdisinfectedchemicallyorphysically(forexamplebylagoonsandmicrofiltration)priortodischargeintoastream,river,bay,lagoonorwetland,oritcanbeusedfortheirrigationofagolfcourse,greenwayorpark.Ifitissufficientlyclean,itcanalsobeusedforgroundwaterrechargeoragriculturalpurposes.Pre-treatmentPre-treatmentremovesmaterialsthatcanbeeasilycollectedfromtherawwastewaterbeforetheydamageorclogthepumpsandskimmersofprimarytreatmentclarifiers(trash,treelimbs,leaves,etc).ScreeningTheinfluentsewagewaterisstrainedtoremovealllargeobjectscarriedinthesewagestream.Thisismostcommonlydonewithanautomatedmechanicallyrakedbarscreeninmodernplantsservinglargepopulations,whilstinsmallerorlessmodernplantsamanuallycleanedscreenmaybeused.Therakingactionofamechanicalbarscreenistypicallypacedaccordingtotheaccumulationonthebarscreensand/orflowrate.Thesolidsarecollectedandlaterdisposedinalandfillorincinerated.GritremovalPre-treatmentmayincludeasandorgritchannelorchamberwherethevelocityoftheincomingwastewateriscarefullycontrolledtoallowsand,gritandstonestosettle.PrimarytreatmentIntheprimarysedimentationstage,sewageflowsthroughlargetanks,commonlycalled"primaryclarifiers"or"primarysedimentationtanks".Thetanksarelargeenoughthatsludgecansettleandfloatingmaterialsuchasgreaseandoilscanrisetothesurfaceandbeskimmedoff.Themainpurposeoftheprimarysedimentationstageistoproducebothagenerallyhomogeneousliquidcapableofbeingtreatedbiologicallyandasludgethatcanbeseparatelytreatedorprocessed.Primarysettlingtanksareusuallyequippedwithmechanicallydrivenscrapersthatcontinuallydrivethecollectedsludgetowardsahopperinthebaseofthetankfromwhereitcanbepumpedtofurthersludgetreatmentstages.Greaseandoilfromthefloatingmaterialcansometimesberecoveredforsaponification.SecondarytreatmentSecondarytreatmentisdesignedtosubstantiallydegradethebiologicalcontentofthesewagewhicharederivedfromhumanwaste,foodwaste,soapsanddetergent.Themajorityofmunicipalplantstreatthesettledsewageliquorusingaerobicbiologicalprocesses.Forthistobeeffective,thebiotarequirebothoxygenandasubstrateonwhichtolive.Thereareanumberofwaysinwhichthisisdone.Inallthesemethods,thebacteriaandprotozoaconsumebiodegradablesolubleorganiccontaminants(e.g.sugars,fats,organicshort-chaincarbonmolecules,etc.)andbindmuchofthelesssolublefractionsintofloc.Secondarytreatmentsystemsareclassifiedasfixed-filmandsuspended-growth.Fixed-filmORattachedgrowthsystemtreatmentprocessincludingtricklingfilterandrotatingbiologicalcontactorswherethebiomassgrowsonmediaandthesewagepassesoveritssurface.Insuspended-growthsystems,suchasactivatedsludge,thebiomassiswellmixedwiththesewageandcanbeoperatedinasmallerspacethanfixed-filmsystemsthattreatthesameamountofwater.However,fixed-filmsystemsaremoreabletocopewithdrasticchangesintheamountofbiologicalmaterialandcanprovidehigherremovalratesfororganicmaterialandsuspendedsolidsthansuspendedgrowthsystems.Roughingfiltersareintendedtotreatparticularlystrongorvariableorganicloads,typicallyindustrial,toallowthemtothenbetreatedbyconventionalsecondarytreatmentprocesses.Characteristicsincludetypicallytall,circularfiltersfilledwithopensyntheticfiltermediatowhichwastewaterisappliedatarelativelyhighrate.Theyaredesignedtoallowhighhydraulicloadingandahighflow-throughofair.Onlargerinstallations,airisforcedthroughthemediausingblowers.Theresultantwastewaterisusuallywithinthenormalrangeforconventionaltreatmentprocesses.ActivatedsludgeMainarticle:ActivatedsludgeIngeneral,activatedsludgeplantsencompassavarietyofmechanismsandprocessesthatusedissolvedoxygentopromotethegrowthofbiologicalflocthatsubstantiallyremovesorganicmaterial.Theprocesstrapsparticulatematerialandcan,underidealconditions,convertammoniatonitriteandnitrateandultimatelytonitrogengas,(seealsodenitrification).Surface-aeratedbasinsMostbiologicaloxidationprocessesfortreatingindustrialwastewatershaveincommontheuseofoxygen(orair)andmicrobialaction.Surface-aeratedbasinsachieve80to90%removalofBiochemicalOxygenDemandwithretentiontimesof1to10days.Thebasinsmayrangeindepthfrom1.5to5.0metresandusemotor-drivenaeratorsfloatingonthesurfaceofthewastewater.Inanaeratedbasinsystem,theaeratorsprovidetwofunctions:theytransferairintothebasinsrequiredbythebiologicaloxidationreactions,andtheyprovidethemixingrequiredfordispersingtheairandforcontactingthereactants(thatis,oxygen,wastewaterandmicrobes).Typically,thefloatingsurfaceaeratorsareratedtodelivertheamountofairequivalentto1.8to2.7

kgO2/kW·h.However,theydonotprovideasgoodmixingasisnormallyachievedinactivatedsludgesystemsandthereforeaeratedbasinsdonotachievethesameperformancelevelasactivatedsludgeunits.Biologicaloxidationprocessesaresensitivetotemperatureand,between0°Cand40°C,therateofbiologicalreactionsincreasewithtemperature.Mostsurfaceaeratedvesselsoperateatbetween4°Cand32°C.Filterbeds(oxidizingbeds)Mainarticle:TricklingfilterInolderplantsandplantsreceivingmorevariableloads,tricklingfilterbedsareusedwherethesettledsewageliquorisspreadontothesurfaceofadeepbedmadeupofcoke(carbonizedcoal),limestonechipsorspeciallyfabricatedplasticmedia.Suchmediamusthavehighsurfaceareastosupportthebiofilmsthatform.Theliquorisdistributedthroughperforatedrotatingarmsradiatingfromacentralpivot.Thedistributedliquortricklesthroughthisbedandiscollectedindrainsatthebase.Thesedrainsalsoprovideasourceofairwhichpercolatesupthroughthebed,keepingitaerobic.Biologicalfilmsofbacteria,protozoaandfungiformonthemedia’ssurfacesandeatorotherwisereducetheorganiccontent.Thisbiofilmisgrazedbyinsectlarvaeandwormswhichhelpmaintainanoptimalthickness.Overloadingofbedsincreasesthethicknessofthefilmleadingtocloggingofthefiltermediaandpondingonthesurface.BiologicalaeratedfiltersBiologicalAerated(orAnoxic)Filter(BAF)orBiofilterscombinefiltrationwithbiologicalcarbonreduction,nitrificationordenitrification.BAFusuallyincludesareactorfilledwithafiltermedia.Themediaiseitherinsuspensionorsupportedbyagravellayeratthefootofthefilter.Thedualpurposeofthismediaistosupporthighlyactivebiomassthatisattachedtoitandtofiltersuspendedsolids.Carbonreductionandammoniaconversionoccursinaerobicmodeandsometimeachievedinasinglereactorwhilenitrateconversionoccursinanoxicmode.BAFisoperatedeitherinupflowordownflowconfigurationdependingondesignspecifiedbymanufacturer.MembranebioreactorsMembranebioreactors(MBR)combineactivatedsludgetreatmentwithamembraneliquid-solidseparationprocess.Themembranecomponentuseslowpressuremicrofiltrationorultrafiltrationmembranesandeliminatestheneedforclarificationandtertiaryfiltration.Themembranesaretypicallyimmersedintheaerationtank;however,someapplicationsutilizeaseparatemembranetank.OneofthekeybenefitsofanMBRsystemisthatiteffectivelyovercomesthelimitationsassociatedwithpoorsettlingofsludgeinconventionalactivatedsludge(CAS)processes.Thetechnologypermitsbioreactoroperationwithconsiderablyhighermixedliquorsuspendedsolids(MLSS)concentrationthanCASsystems,whicharelimitedbysludgesettling.TheprocessistypicallyoperatedatMLSSintherangeof8,000–12,000

mg/L,whileCASareoperatedintherangeof2,000–3,000

mg/L.TheelevatedbiomassconcentrationintheMBRprocessallowsforveryeffectiveremovalofbothsolubleandparticulatebiodegradablematerialsathigherloadingrates.ThusincreasedSludgeRetentionTimes(SRTs)—usuallyexceeding15days—ensurecompletenitrificationeveninextremelycoldweather.ThecostofbuildingandoperatinganMBRisusuallyhigherthanconventionalwastewatertreatment.Membranefilterscanbeblindedwithgreaseorabradedbysuspendedgritandlackaclarifier'sflexibilitytopasspeakflows.Thetechnologyhasbecomeincreasinglypopularforreliablypretreatedwastestreamsandhasgainedwideracceptancewhereinfiltrationandinflowhavebeencontrolled,however,andthelife-cyclecostshavebeensteadilydecreasing.ThesmallfootprintofMBRsystems,andthehighqualityeffluentproduced,makethemparticularlyusefulforwaterreuseapplications.ThereareMBRplantsbeingbuiltthroughouttheworld,includingNorthLibrty,Iowa,Georgia,andCanada.SecondarysedimentationThefinalstepinthesecondarytreatmentstageistosettleoutthebiologicalflocorfiltermaterialandproducesewagewatercontainingverylowlevelsoforganicmaterialandsuspendedmatter.RotatingbiologicalcontactorsMainarticle:RotatingbiologicalcontactorRotatingbiologicalcontactors(RBCs)aremechanicalsecondarytreatmentsystems,whicharerobustandcapableofwithstandingsurgesinorganicload.RBCswerefirstinstalledinGermanyin1960andhavesincebeendevelopedandrefinedintoareliableoperatingunit.Therotatingdiskssupportthegrowthofbacteriaandmicro-organismspresentinthesewage,whichbreakdownandstabiliseorganicpollutants.Tobesuccessful,micro-organismsneedbothoxygentoliveandfoodtogrow.Oxygenisobtainedfromtheatmosphereasthedisksrotate.Asthemicro-organismsgrow,theybuilduponthemediauntiltheyaresloughedoffduetoshearforcesprovidedbytherotatingdiscsinthesewage.EffluentfromtheRBCisthenpassedthroughfinalclarifierswherethemicro-organismsinsuspensionsettleasasludge.Thesludgeiswithdrawnfromtheclarifierforfurthertreatment.Afunctionallysimilarbiologicalfilteringsystemhasbecomepopularaspartofhomeaquariumfiltrationandpurification.Theaquariumwaterisdrawnupoutofthetankandthencascadedoverafreelyspinningcorrugatedfiber-meshwheelbeforepassingthroughamediafilterandbackintotheaquarium.Thespinningmeshwheeldevelopsabiofilmcoatingofmicroorganismsthatfeedonthesuspendedwastesintheaquariumwaterandarealsoexposedtotheatmosphereasthewheelrotates.Thisisespeciallygoodatremovingwasteureaandammoniaurinatedintotheaquariumwaterbythefishandotheranimals.污水处理摘要自然或生活污水处理，是指清除包括家庭排放的和地面径流在内的污水废水和地面污染物的过程。它包括物理，化学和生物过程，消除物理，化学和生物污染物。其目的是集中产生废物流（或经处理的污水）以及固体废物或污泥进行处理或再进入环境。这种污物通常是在无意中受到了许多有毒的有机和无机物的污染。关键词：污水处理，生物膜处理法和停止增长生物处理法，活性污泥法，污水起源污水是由个人住宅，机关，商业和工业机构产生的。原进水（污水）包括家庭的厕所，浴室，淋浴，厨房，水槽废液等等，这些水将通过污水管排放。在许多地区，污水也包括工业和商业污水。在发达国家，家居分别将污水排放为灰水和黑水已经越来越普遍，因为灰水可以用于浇灌植物或回收用来冲马桶。大量的污水还包括一些屋顶流下的水以及地表水。因此城市废水包括住宅，商业和工业排放的废水，且可能包括雨水径流。具有处理雨水能力的污水处理系统被称为合流排水系统。这种系统通常是不被普遍采用，因为它们复杂化而且由于其季节性，降低了污水处理厂的效率。由于流量的经常变化，也导致处理量往往大于必需的，因而使处理设施更昂贵。此外，当遭遇暴雨时，过量的雨水会造成污水处理能力不足，因而引发溢流。因此在设计排水管网时最好采用雨污分流系统。由于降雨流经屋顶和地面时，会带走包括土壤颗粒和其他沉积物，重金属，有机物，动物排泄物，污油和油脂等各种污染物质。因此有些地方会有法律要求在雨水排入河道之前要进行一些一定水平的处理。例如以下对雨水进行的处理：盆地沉淀处理，湿地过滤处理，混凝土地窖过滤处理，和旋涡分离器（去除粗固体）。过程概述污水可以在下列构筑物(化粪池，生物过滤器或好氧处理系统）附近被处理，或收集并通过排水管网和泵站送至城市污水处理厂（见污水处理和管道和基础设施）。污水收集和处理，通常取决于当地州和联邦法规和标准。来源于的工业废水，往往需要专门的处理过程（见工业废水处理）。常规污水处理可能涉及三个阶段，一级处理，二级处理和三级处理。一级处理包括在沉淀池中的短时停留，这样比较重的固体就会沉到池底，而油，油脂，更轻的固体则浮到水面。沉淀的和浮动的材料都将被去除，其余的液体可被释放或继续二级处理。二级处理可以去除溶解和悬浮的生物物质。二级处理通常由好氧或厌氧微生物进行。二级处理还可能需要一个分离过程，以去除残余的微生物或进行三级处理。三级处理有时被界定为与一级和二级不同的过程。受处理的水在排放到河流，海湾，泻湖或湿地前有时需要化学消毒或物理（例如泻湖和微滤）处理，或者可以用于灌溉高尔夫球场，绿色道路或公园。如果它足够清洁，也可以用于地下水回灌或农业用途。预处理预处理可以从原始废水除去垃圾，树枝，树叶等比较容易收集的物质，以防止其损坏或阻塞水泵和一级处理的澄清池处理。筛选进水污水必须消除随污水流进行的大的污染物。在服务大量人口的现代化处理厂，经常用自动倾斜格栅来达到这个目的。而小的处理厂可能采用手动的格栅。机械式格栅的清污是典型的以格栅污物积累或流量的积累来进行的。收集到的固体将被进行填埋或焚烧处理。除砂预处理可使包括沙子或砂砾在内的物质通过控制速度在渠道或厅室内旋转流动，使砂，砂砾和石块沉淀。初级处理在初级沉淀阶段，污水流经一个大池子，俗称“初级澄清池”或“初级沉淀池”。这些池子需要足够大以令污泥可以沉淀而油和油脂等漂浮物可以上升到表面，并掠出池子。在初级沉淀阶段的主要目的是提供一个均匀的液态环境使微生物和污泥都能被处理。初级沉淀池，通常装配有机械驱动的刮削泥器，不断推动将污泥收集到底部污泥斗，从那里可以抽取污泥进行进一步处理。油脂和石油的漂浮物有时会回收进行皂化。二级处理二级处理的设计是为了降低了污水中那些来自人类垃圾，食物渣滓，肥皂和洗涤剂产生的生化生物污染。大多数市政都打算采用好氧生物的方法解决污水处理问题。为了达到这个目的，生物既需要的氧也需要生活的底物。有多种方式来达到这个目的。在所有这些方法中，细菌和原生动物生物都可以降解消耗水中的水溶性有机污染物（如糖，脂肪，有机短链碳分子等），将大部分可溶性组分结合成絮状。二级处理系统被分为生物膜处理法和停止增长生物处理法。生物膜处理法和停止增长生物处理法系统的处理流程包括生物滤池和生物转盘，它们提供生物生长的媒体以使污水流过时进行处理。在停止增长生物处理法如活性污泥系统中，生物质可以与与污水充分混合，而且在处理等量污水时可以比膜系统采用更小的空间操作。然而，生物膜系统比停止增长生物处理法更能够应付生物污染物数量急的剧变化，并能提供更高的有机物及悬浮固体去除率。粗过滤器是为了处理特别强烈的或可变有机负荷，一般工业，允许它们由传统的二级处理工艺处理后在进行处理。在废水处理程度要求较高的地方，典型的特征包括高及包含开放合成过滤介质的圆形填充过滤器。它们的目的是允许通过高负荷的水力和高速流动的空气。在较大的装置中，使用鼓风机以使空气强行通过装置。由此产生的废水通常在常规处理工艺的正常范围内。活性污泥法主条目：活性污泥一般来说，生物活性污泥法涵盖的各种机制和方法，通过溶解氧，以促进生物絮体增长，以此极大地消除有机物质的。这个过程中的颗粒物质在理想的条件下，可将氨转化为亚硝酸盐和硝酸盐，并最终为氮气（另见反硝化）。表面曝气池大部分