污水處理給排水專業(yè)英文文獻翻譯

污水處理---給排水專業(yè)英文文獻翻譯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.污水處理摘要自然或生活污水處理，是指清除包括家庭排放的和地面徑流在內(nèi)的污水廢水和地面污染物的過程。它包括物理，化學和生物過程，消除物理，化學和生物污染物。其目的是集中產(chǎn)生廢物流（或經(jīng)處理的污水）以及固體廢物或污泥進行處理或再進入環(huán)境。這種污物通常是在無意中受到了許多有毒的有機和無機物的污染。關(guān)鍵詞：污水處理，生物膜處理法和停止增長生物處理法，活性污泥法，污水起源污水是由個人住宅，機關(guān)，商業(yè)和工業(yè)機構(gòu)產(chǎn)生的。原進水（污水）包括家庭的廁所，浴室，淋浴，廚房，水槽廢液等等，這些水將通過污水管排放。在許多地區(qū)，污水也包括工業(yè)和商業(yè)污水。在發(fā)達國家，家居分別將污水排放為灰水和黑水已經(jīng)越來越普遍，因為灰水可以用于澆灌植物或回收用來沖馬桶。大量的污水還包括一些屋頂流下的水以及地表水。因此城市廢水包括住宅，商業(yè)和工業(yè)排放的廢水，且可能包括雨水徑流。具有處理雨水能力的污水處理系統(tǒng)被稱為合流排水系統(tǒng)。這種系統(tǒng)通常是不被普遍采用，因為它們復(fù)雜化而且由于其季節(jié)性，降低了污水處理廠的效率。由于流量的經(jīng)常變化，也導致處理量往往大于必需的，因而使處理設(shè)施更昂貴。此外，當遭遇暴雨時，過量的雨水會造成污水處理能力不足，因而引發(fā)溢流。因此在設(shè)計排水管網(wǎng)時最好采用雨污分流系統(tǒng)。由于降雨流經(jīng)屋頂和地面時，會帶走包括土壤顆粒和其他沉積物，重金屬，有機物，動物排泄物，污油和油脂等各種污染物質(zhì)。因此有些地方會有法律要求在雨水排入河道之前要進行一些一定水平的處理。例如以下對雨水進行的處理：盆地沉淀處理，濕地過濾處理，混凝土地窖過濾處理，和旋渦分離器（去除粗固體）。過程概述污水可以在下列構(gòu)筑物(化糞池，生物過濾器或好氧處理系統(tǒng)）附近被處理，或收集并通過排水管網(wǎng)和泵站送至城市污水處理廠（見污水處理和管道和基礎(chǔ)設(shè)施）。污水收集和處理，通常取決于當?shù)刂莺吐?lián)邦法規(guī)和標準。來源于的工業(yè)廢水，往往需要專門的處理過程（見工業(yè)廢水處理）。常規(guī)污水處理可能涉及三個階段，一級處理，二級處理和三級處理。一級處理包括在沉淀池中的短時停留，這樣比較重的固體就會沉到池底，而油，油脂，更輕的固體則浮到水面。沉淀的和浮動的材料都將被去除，其余的液體可被釋放或繼續(xù)二級處理。二級處理可以去除溶解和懸浮的生物物質(zhì)。二級處理通常由好氧或厭氧微生物進行。二級處理還可能需要一個分離過程，以去除殘余的微生物或進行三級處理。三級處理有時被界定為與一級和二級不同的過程。受處理的水在排放到河流，海灣，瀉湖或濕地前有時需要化學消毒或物理（例如瀉湖和微濾）處理，或者可以用于灌溉高爾夫球場，綠色道路或公園。如果它足夠清潔，也可以用于地下水回灌或農(nóng)業(yè)用途。預(yù)處理預(yù)處理可以從原始廢水除去垃圾，樹枝，樹葉等比較容易收集的物質(zhì)，以防止其損壞或阻塞水泵和一級處理的澄清池處理。篩選進水污水必須消除隨污水流進行的大的污染物。在服務(wù)大量人口的現(xiàn)代化處理廠，經(jīng)常用自動傾斜格柵來達到這個目的。而小的處理廠可能采用手動的格柵。機械式格柵的清污是典型的以格柵污物積累或流量的積累來進行的。收集到的固體將被進行填埋或焚燒處理。除砂預(yù)處理可使包括沙子或砂礫在內(nèi)的物質(zhì)通過控制速度在渠道或廳室內(nèi)旋轉(zhuǎn)流動，使砂，砂礫和石塊沉淀。初級處理在初級沉淀階段，污水流經(jīng)一個大池子，俗稱“初級澄清池”或“初級沉淀池”。這些池子需要足夠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。在初級沉淀階段的主要目的是提供一個均勻的液態(tài)環(huán)境使微生物和污泥都能被處理。初級沉淀池，通常裝配有機械驅(qū)動的刮削泥器，不斷推動將污泥收集到底部污泥斗，從那里可以抽取污泥進行進一步處理。油脂和石油的漂浮物有時會回收進行皂化。二級處理二級處理的設(shè)計是為了降低了污水中那些來自人類垃圾，食物渣滓，肥皂和洗滌劑產(chǎn)生的生化生物污染。大多數(shù)市政都打算采用好氧生物的方法解決污水處理問題。為了達到這個目的，生物既需要的氧也需要生活的底物。有多種方式來達到這個目的。在所有這些方法中，細菌和原生動物生物都可以降解消耗水中的水溶性有機污染物（如糖，脂肪，有機短鏈碳分子等），將大部分可溶性組分結(jié)合成絮狀。二級處理系統(tǒng)被分為生物膜處理法和停止增長生物處理法。生物膜處理法和停止增長生物處理法系統(tǒng)的處理流程包括生物濾池和生物轉(zhuǎn)盤，它們提供生物生長的媒體以使污水流過時進行處理。在停止增長生物處理法如活性污泥系統(tǒng)中，生物質(zhì)可以與與污水充分混合，而且在處理等量污水時可以比膜系統(tǒng)采用更小的空間操作。然而，生物膜系統(tǒng)比停止增長生物處理法更能夠應(yīng)付生物污染物數(shù)量急的劇變化，并能提供更高的有機物及懸浮固體去除率。粗過濾器是為了處理特別強烈的或可變有機負荷，一般工業(yè)，允許它們由傳統(tǒng)的二級處理工藝處理后在進行處理。在廢水處理程度要求較高的地方，典型的特征包括高及包含開放合成過濾介質(zhì)的圓形填充過濾器。它們的目的是允許通過高負荷的水力和高速流動的空氣。在較大的裝置中，使用鼓風機以使空氣強行通過裝置。由此產(chǎn)生的廢水通常在常規(guī)處理工藝的正常范圍內(nèi)。活性污泥法主條目：活性污泥一般來說，生物活性污泥法涵蓋的各種機制和方法，通過溶解氧，以促進生物絮體增長，以此極大地消除有機物質(zhì)的。這個過程中的顆粒物質(zhì)在理想的條件下，可將氨轉(zhuǎn)化為亞硝酸鹽和硝酸鹽，并最終為氮氣（另見反硝化）。表面曝氣池大部分