環(huán)境科學(xué)和工程專(zhuān)業(yè)英語(yǔ)翻譯

./第四單元閱讀材料：ReadingMaterial:AnalyticalTechniqueandMethodology第八單元：空氣污染物的來(lái)源和類(lèi)型第八單元ReadingMaterial:TypeandSourcesofAirPollutants[IIJ閱讀材料：空氣污染物的類(lèi)型和來(lái)源〔ⅡWhatarePCBs?什么是多氯聯(lián)苯？Thereare209possiblechlorinatedbiphenyls,ranginginphysicalcharacteristics.大概有209種氯化聯(lián)苯,其物理性質(zhì)不同。Themono-anddichlorobiphenyls<27323-18-8>,<25512-42-9>arecolorlesscrystallinecompoundsthatwhenburnedinairgiverisetosootandhydrogenchloride.一氯聯(lián)苯和二氯聯(lián)苯〔27323-18-8,〔25512-42-9是無(wú)色晶體的化合物,當(dāng)它們?cè)诳諝庵腥紵龝?huì)產(chǎn)生煙塵和氯化氫。Themostimportantproductsaretri-chlorobiphenyls,tetrachlorobiphenyls,pentachlorobiphenylsand/orhexachlorobiphenyls.最重要的產(chǎn)品是三-氯化聯(lián)苯,四氯聯(lián)苯,五氯聯(lián)苯和/或六氯聯(lián)苯。Chlorinatedbiphenylsaresolubleinmanyorganicsolventsandinwateronlyintheppmrange.多氯聯(lián)苯可溶于有機(jī)溶劑和僅在水的百萬(wàn)分之一ppm〔partpermillion的范圍內(nèi)溶解。Althoughchemicallystable<includingtooxygenoftheair>theycanbehydrolyzedtooxybiphenylsunderextremeconditionsformingtoxicpolychlorodibenzofurans.氯化聯(lián)苯易溶于在許多有機(jī)溶劑和水只有在的范圍內(nèi)的可溶性。雖然化學(xué)穩(wěn)定性〔包括空氣中的氧氣但是在一定條件下,多氯聯(lián)苯可水解氧化成二氧化苯極端條件下形成的有毒的多氯代苯并二噁英。ThePCBclassofcompoundsreceivedsubstantialattentionandnotorietywhenin1968,inJapan,accidentalpoisoningoccurredbycookingriceinbranoilcontaminatedbyPCBs.在1968年,多氯聯(lián)苯類(lèi)化合物受到實(shí)質(zhì)性的的關(guān)注和得到臭名,日本用受到多氯聯(lián)苯污染的米糠油做飯的意外中毒事件。Over1000patientssufferedfromvariousmorbidsymptoms.超過(guò)1000例患者出現(xiàn)各種病態(tài)癥狀。AsimilarpoisoningoccurredinTaiwanin1979.CausativeagentswereconsideredtobecoconaminantsofPCBssuchaspoly-chlorinateddibenzofuransthataresecondarilyformedduringheatingofPCBscongenersincommercialPCBmixturesandrequireasecondlookatPCBtoxicity.1979年XX有一個(gè)類(lèi)似的中毒事件。病原體被認(rèn)為是如多氯二苯并呋喃的多氯聯(lián)苯,其次是PCBs多氯聯(lián)苯同系物在商業(yè)PCB混合物在加熱過(guò)程中形成的,需要第二次看看PCB的毒性。PCBregulation多氯聯(lián)苯的管理BecauseofconcernsregardingPCB'shealtheffectsandevidenceofpresenceandpersistenceintheenvironmentfurthermanufactureofthechemicalwasbannedunderThe1976ToxicSubstanceControlAct.由于擔(dān)心多氯聯(lián)苯對(duì)健康的影響和證明存在以及持續(xù)在環(huán)境中會(huì)進(jìn)一步制造化學(xué)物質(zhì)的,在1976年美國(guó)有毒物質(zhì)控制法中被禁止了。PCBregulationsprovidedeadlinesforremovalofmostin-usecapaci-torsandtransformerscontainingPCBs·andlimittimeforstoragefordisposaltooneyear.多氯聯(lián)苯的管理提出最后期限為了最大去除使用電容器和變壓器逗留的多氯聯(lián)苯和限制儲(chǔ)存一年就要處理。EPAhasallowedcontinueduseofPCBsinelectricaltransformersandcapacitorswhentheagencydidnotposeunreasonablerisk.當(dāng)經(jīng)銷(xiāo)產(chǎn)品不會(huì)產(chǎn)生過(guò)度的危險(xiǎn)時(shí),環(huán)境保護(hù)局允許繼續(xù)使用含多氯聯(lián)苯的電子電容器和變壓器。Capacitors,exceptthoseinisolatedareasshouldhavebeenremovedbyOctober1988,andtransformersofacertainsizeinornearcommercialbuildingsshouldberemovedbyOctober1990.電容器,除了那些分散地方的應(yīng)該被移走在1988年10月之后,變壓器的某一些型號(hào)和靠近商業(yè)建筑的應(yīng)該被移走在1990年10月后。EPAregulationsrequirethatPCBstakenoutofservicebedisposedofeitherbyspeciallydesignedhightemperatureincineratorsneededtobreakhighconcentrationsofPCBstoharm-lesscomponentsorbyalternatedestructionmethodsapprovedbytheagency.EnvironmentalProtectionAgency美國(guó)環(huán)保署,法規(guī)要求PCB服務(wù)多氯聯(lián)苯或者處置的,通過(guò)特別設(shè)計(jì)的高溫焚化爐需要打破高濃度的多氯聯(lián)苯的無(wú)害組件或替代由該機(jī)構(gòu)批準(zhǔn)的銷(xiāo)毀方法。Oilscontami-natedwithlowconcentrations<50-500ppm>maybedisposedbyhighefficiencyboilers.低濃度〔50?500PPM污染的油可以通過(guò)高效率的鍋爐處理。ThelimitednumberofincineratorsapprovedforPCBincinerationandthehighcostofbuildingadditionalincineratorshavegivenincentiveforalternatedestructionmethods.AlternatetechnologiesmustbecapableofoperatingaseffectivelyasEPA'sincinerationeffi-ciency.批準(zhǔn)用于焚燒多氯聯(lián)苯的焚燒爐數(shù)量被限制和成本高且附有焚燒爐的建筑鼓勵(lì)使用一一分解的方法。選擇的技術(shù)的運(yùn)轉(zhuǎn)效率必須能夠達(dá)到環(huán)境保護(hù)局的焚燒效率。PCBsinelectricaltransformers多氯聯(lián)苯的電流體變壓器Therewere304millionlbofPCBsusedaselectricalfluidinapproximately150000askarel<non-flammableelectricalfluid>transformersintheUnitedStates.在美國(guó)有304百萬(wàn)磅的多氯聯(lián)苯被當(dāng)做電流體使用,大約150000阿斯卡列〔不易燃的電流體變壓器。About70000PCBtrans-formersareinornearcommercialbuildingsthatareopentothepublic.大約70000多氯聯(lián)苯變壓器建在或靠近對(duì)公眾開(kāi)放的商業(yè)建筑。About40000ofthesetransformersareownedbyelectricalutilities.Approximately15000ofthesetransformersareusedinthefoodandfeedindustry.大約40000這些變壓器缺少電設(shè)施。大約15000這些變壓器被使用在食品和飼料工業(yè)。Utilitiesandotherindustriesmustmaintainordisposeofapproximately150000askarel-typetransformersthatmaydevelopleaks.公用事業(yè)等行業(yè)必須保持或處置約150000氯代聯(lián)苯-型變壓器可能出現(xiàn)的漏洞。Eachyear,anestimated317askarel-typetrans-formerscanbeexpectedtoleak.Eachwillloseabout5.3galor66lbofPCBs.公共設(shè)施和其他工業(yè)必須維護(hù)或處理大約150000阿斯卡列型變壓器可能產(chǎn)生的泄露,每一年,估計(jì)317阿斯卡列型變壓器被暴露泄露,將損失5.3㎡/s或66磅多氯聯(lián)苯。Transformersclassification變壓器的分類(lèi)TheEPAhasthreeclassificationfortransformers:環(huán)保局已對(duì)變壓器三分類(lèi)：PCBtransformerscontain500ormoreppmPCBs.多氯聯(lián)苯變壓器,多氯聯(lián)苯含量在百萬(wàn)分之500或超過(guò)百萬(wàn)分之一。Theymustbeinspectedquarterlyforleaks,anddetailedrecordsmustbekept.每季度被檢查出的泄露會(huì)被詳細(xì)的記錄并保存。Nomaintenanceworkinvolvingremovalofthecoreisallowed.除去核心沒(méi)有維持工作涉及的是被允許的。Attheendofthetransformers'usefullife,itmustbedestroyedinanEPA-approvedfacility,orthetransformerliquidmustbeincineratedandthecarcasslandfilled.在變壓器有效壽命的盡頭,它會(huì)被環(huán)境保護(hù)局支持的設(shè)施銷(xiāo)毀,或變壓器的液體被焚燒和外殼被掩埋。ThecourtsandtheEPAhaveheldtheoriginaltransformerownerliableforleakagethatmayoccurforaslongasthecarcassremainsinthelandfill.環(huán)境保護(hù)局要呼吁變最初壓器擁有者對(duì)液體泄漏負(fù)責(zé)任并且提供足夠大的場(chǎng)地對(duì)變壓器掩埋。PCB-contaminatedtransformerscontainbetween50and400ppmPCBsandrequirean-nualinspection.Theruleconcerningdisposal,maintenance,andrecordkeepingarelessre-strictiveandlesscostlythanthoseforPCBtransformers.受多氯聯(lián)苯污染的變壓器,多氯聯(lián)苯含量在百萬(wàn)分之50至百萬(wàn)分之400之間和要求必須每年檢查。管理涉及處理、維護(hù)、記錄保持在最小限制或者接近多氯聯(lián)苯變壓器要求的含量。Non-PCBtransformershavelessthan50ppmPCBsandareexemptfromtheburden-somerulesandrequirementsthatapplytoPCBandPCBscontaminatedtransformers.沒(méi)有多氯聯(lián)苯的變壓器,多氯聯(lián)苯含量少于百萬(wàn)分之50和免除了一些繁雜的規(guī)則和要求比在應(yīng)用于多氯聯(lián)苯變壓器和受多氯聯(lián)苯污染的變壓器。Non-PCBtransformersaregrantedfavorundertheToxicSubstancesControlAct.沒(méi)有多氯聯(lián)苯的變壓器被包含在美國(guó)有毒物質(zhì)控制法里。AnalysisofPCBs多氯聯(lián)苯分析Analyticalmethodsmostfrequentlyusedfordetectingchlorinatedbiphenylsarecapillarycol-umngaschromatographycoupledwithmassspectrometryintheMID<MultipleIonDetec-tion>modeandcapillarycolumngaschromatographywithECD<ElectronCaptureDetec-tor>.分析法最頻繁用于發(fā)現(xiàn)含氯聯(lián)苯,在多離子檢測(cè)的模式下頂空毛管氣象色譜與質(zhì)譜分析結(jié)合、頂空毛管氣象色譜與電子捕獲測(cè)器結(jié)合。HPLC<HighPressureLiquidChromatography>andinfraredspectroscopyareapplica-bletoalimitedextent.高效液相色譜和紅外光譜適用于限制的范圍。SummaryPCBdeterminationsarealsopossible,thoughnotusual.Theserequireexhaustivechlorinationandmeasurementofthedecachlorbiphenycontentordechlorinationandsubsequentbiphenylmeasurement.總結(jié),多氯聯(lián)苯的測(cè)定盡管不常用,也是有可能的。這是需要徹底的氯化作用好十氯聯(lián)苯內(nèi)容的測(cè)定或者脫氯后聯(lián)苯的測(cè)定。InfraredtestedonPCBs多氯聯(lián)苯的紅外測(cè)試InfraredthermaltreatmenttechnologywasfieldtestedforeffectivenessonPCBscontamina-tedsoilattwoSuperfundsitesduring1986.在1986年期間,紅外熱治療技術(shù)在倆個(gè)超級(jí)基金地被現(xiàn)場(chǎng)檢測(cè)受多氯聯(lián)苯污染的土地的有效性。Thetransportablepilotsystemconsistedofaprimaryfurnacethroughwhichsolid/semisolidwasteswereconveyedonawiremeshbelt.移動(dòng)式試驗(yàn)系是由一個(gè)一次火爐通過(guò)固體/半固體廢物被傳送到鋼絲網(wǎng)運(yùn)輸帶。Theheatsourcewassuppliedbyelectricglowbarsinlieuofgaseousfuels.火源通過(guò)發(fā)電光棒代替氣體燃料提供。Residencetimesandfurnacetemperaturescouldbecontrolledmanuallyorautomaticallygivinguniformash.為了提供均化灰分,停留時(shí)間和燃燒爐溫度可以手動(dòng)或自動(dòng)控制。Asecondarychamber,heatedbyelectricorgaseousfuels,followedtheprimaryfurnaceandprovidedtemperaturesmexcessof220°F.ThesystemwasdesignedtocomplywithallRCRAandTSCArequirements.二次火爐通過(guò)電或氣體燃料加熱,與一次火爐一樣和提供的溫度超過(guò)2200F。系統(tǒng)被設(shè)計(jì)成符合資源保護(hù)和回收法案以及美國(guó)有毒物質(zhì)控制法要求。Selectfrom"PaulN.C.,Highhazardouspollutants,Asestos,PCBs,dioxins,biomedicalwastes,PollutionEngineering,Vol.21,No.2,1989"unit12Text:WaterPollutionandPollutants第十二單元：水污染與污染物Therelationshipbetweenpollutedwateranddiseasewasfirmlyestablishedwiththecholeraepidemicof1854inLondo,England.Protectionofpublichealth,theoriginalpurposeofpollutioncontrol,continuestobetheprimaryobjectiveinmanyareas.1854年英國(guó)倫敦爆發(fā)了大規(guī)模的流行性霍亂。此事明確地證實(shí)了污水和疾病之間的關(guān)系。當(dāng)初以公共健康為目的所采取的污染控制,依然是許多地區(qū)的主要目的。However,preserva-tionofwaterresources,protectionoffishingareas,andmaintenanceofrecreationalwatersareadditionalconcernstoday.然而,水資源的保持,產(chǎn)魚(yú)區(qū)的防護(hù),以及娛樂(lè)活動(dòng)用水的維持在今天也成為關(guān)注的焦點(diǎn)。WaterpollutionproblemsintensifiedfollowingWorldWarIIwhendramaticincreasesinurbandensityandindustrializationoccurred.緊隨第二次世界大戰(zhàn)之后所產(chǎn)生的城市人口密度突增和工業(yè)化進(jìn)程的加劇,都使得水污染問(wèn)題越見(jiàn)明顯。Concernoverwaterpollutionreachedapeakinthemid-seventies.致使對(duì)于水污染的關(guān)注程度在70年代中期達(dá)到了頂峰。Waterpollutionisanimprecisetermthatrevealsnothingabouteitherthetypeofpollu-tingmaterialoritssource.Thewaywedealwiththewasteproblemdependsuponwhetherthecontaminantsareoxygendemanding,algaepromoting,infectious,toxic,orsimplyun-sightly.水污染是一個(gè)不準(zhǔn)確的術(shù)語(yǔ),它并未指出污染物的種類(lèi)和來(lái)源。而我們處理廢水問(wèn)題的方式往往取決于以下幾個(gè)方面：污染物是否需要氧氣,是否助長(zhǎng)藻類(lèi),是否有傳染性,是否有毒,或者僅僅是否好看。Pollutionofourwaterresourcescanoccurdirectlyfromseweroutfallsorindustrialdischarges<pointsources>orindirectlyfromairpollutionoragriculturalorurbanrunoff<nonpointsources>.水源的污染可能直接來(lái)自生活污水的排放或工廠污水排放〔點(diǎn)源,也可能間接地由空氣污染、農(nóng)業(yè)排水或城市排水〔非點(diǎn)源所引發(fā)。Chemicallypurewater1sacollectionofH20molecules--nothingelse.化學(xué)上所謂的純水僅僅是水分子的集合。Suchasub-stanceisnotfoundinnature--notinwildstreamsorlakes,notincloudsorrain,notinfallingsnow,norinthepolaricecaps.無(wú)論在野外的河流或湖泊、云層或雨水中,還是在下雪期間,極地的冰帽地區(qū),這種物質(zhì)在自然界均不能找到。Verypurewatercanbepreparedinthelaboratorybutonlywithconsiderabledifficulty.然而在實(shí)驗(yàn)室中可以制備非常純凈的水,但是存在一定的困難。Wateracceptsandholdsforeignmatter.因?yàn)樗畼O易接受和容納外來(lái)物質(zhì)。Municipalwastewater,alsocalledsewage,isacomplexmixturecontammgwater<usuallyover99percent>togetherwithorganicandinorganiccontaminants,bothsuspen-dedanddissolved.城市污水,也被稱(chēng)作生活污水,是一種復(fù)雜的混合物,它包含水〔通常超過(guò)99％以及懸浮或溶解的有機(jī)和無(wú)機(jī)污染物。Theconcentrationofthesecontaminantsisnormallyverylowandisex-pressedinmg/L,thatis,milligramsofcontaminantperliterofthemixture.這些污染物的濃度通常很低并且以mg/L來(lái)表示,也就說(shuō),每升混合物含有多少毫克污染物。Thisisaweight-to-volumeratiousedtoindicateconcentrationsofconstituentsinwater,wastewater,industrialwastes,andotherdilutesolutions.重量與體積比也常用來(lái)表示在水、廢水、工業(yè)廢水和其它稀釋溶液中的污染物濃度。Microorganisms.Whereverthereissuitablefood,sufficientmoisture,andanappropri-atetemperature,microorganismswillthrive.微生物任何地方只要存在適合的食物,充足的濕度和適當(dāng)?shù)臏囟?微生物即可大量繁殖。Sewageprovidesanidealenvironmentforavastarrayofmicrobes,primarilybacteria,plussomevirusesandprotozoa.而生活污水為各種各樣的微生物提供了一個(gè)理想的環(huán)境。這些微生物主要是細(xì)菌,某些病毒和原生動(dòng)物。Mostofthesemicroorganismsinwastewaterareharmlessandcanbeemployedinbiologicalprocessestoconvertorganicmattertostableendproducts.廢水中的大多數(shù)微生物是無(wú)害的,并且可借助生化過(guò)程,將有機(jī)物轉(zhuǎn)化為穩(wěn)定的最終產(chǎn)物。However,sewagemayalsocontainpathogensfromtheexcretaofpeoplewithinfectiousdiseasesthatcanbetransmittedbycontaminatedwater.但是當(dāng)一些人患有可通過(guò)有毒廢水傳播的傳染性疾病時(shí),其排泄物所攜帶的致病病原體,極有可能成為污水的組成部分。Waterbornebacterialdiseasessuchascholera,typhoid,andtuberculosis,viraldis-easessuchasinfectioushepatitis,andtheprotozoan-causeddysentery,whileseldomaprob-lemnowindevelopedcountries,arestillathreatwhereproperlytreatedwaterisnotavai-lableforpublicuse.雖然在發(fā)達(dá)國(guó)家,類(lèi)似于水傳播的細(xì)菌性疾病,例如霍亂、傷寒和肺結(jié)核,病毒性疾病例如傳染性的肝炎和原生蟲(chóng)引起的痢疾,已經(jīng)不再是問(wèn)題,但是在那些經(jīng)過(guò)適當(dāng)處理過(guò)的污水不能被公共利用的地區(qū)仍然存在著很大威脅。Testsforthefewpathogensthatmightbepresentaredifficultandtimecon-suming,andstandardpracticeistotestforothermoreplentifulorganismsthatarealwayspres-ent<inthebillions>intheintestinesofwarm-bloodedanimals,includinghumans.對(duì)于少量存在的病原體的檢測(cè)是相當(dāng)困難和耗時(shí)的。其標(biāo)準(zhǔn)做法是檢測(cè)存在于包括人類(lèi)在內(nèi)的〔數(shù)十億熱血?jiǎng)游锬c胃中的有機(jī)物。Solids.固體Thetotalsolids<organicplusinorganic>inwastewaterare,bydefinition,theres-iduesaftertheliquidportionhasbeenevaporatedandtheremainderdriedtoaconstantweightat103℃.廢水中的總固體〔包括有機(jī)的和無(wú)機(jī)的是指液體部分被蒸發(fā),并且在103℃烘干至恒重的殘余物。Differentiationbetweendissolvedsolidsandundissolved,thatis,suspended,solidsareaccomplishedbyevaporatingfilteredandunfilteredwastewatersamples.區(qū)分可溶性固體和懸浮固體的方法,是通過(guò)蒸發(fā)過(guò)濾的和沒(méi)有通過(guò)過(guò)濾的廢水樣品來(lái)進(jìn)行的。Thedifferenceinweightbetweenthetwodriedsamplesindicatesthesuspendedsolidscontent.兩種烘干樣品質(zhì)量的差值即表示懸浮物的質(zhì)量。Tofurthercategorizetheresidues,theyareheldat550"Cfor15minutes.Theashremainingisconsideredtorepresentinorganicsolidsandthelossofvolatilemattertobeameasureoftheorganiccontent.將殘留物在550℃溫度下保持15分鐘以進(jìn)一步分類(lèi),剩余的灰代表了無(wú)機(jī)物,失去的揮發(fā)物則代表有機(jī)物的重量。Suspendedsolids<SS>andvolatilesuspendedsolids<VSS>arethemostuseful.懸浮固體〔SS和揮發(fā)性的懸浮固體〔VSS是最有用的。SSandBOD<biochemicaloxygendemand>areusedasmeasuresofwastewaterstrengthandprocessperformance.SS和BOD〔生化需氧量是廢水的受污染程度及其過(guò)程性能的指標(biāo)。VSScanbeanindicatoroftheorganiccontentofrawwastesandcanal-soprovideamea:mreoftheactivemicrobialpopulationinbiologicalprocesses.VSS可以指示廢水中有機(jī)物的含量,也可以衡量在生化過(guò)程里活性的微生物群。Inorganicconstituents.Thecommoninorganicconstituentsofwastewaterinclude:無(wú)機(jī)成分廢水中常見(jiàn)的無(wú)機(jī)成分包括：1. Chloridesandsulphates.Normallypresentinwaterandinwastesfromhumans.1．氯化物和硫酸鹽。常見(jiàn)于人類(lèi)排放的廢水和廢物中。2. Nitrogenandphosphorous<D.Intheirvariousforms<organicandinorganic>inwastesfromhumans,withadditionalphosphorousfromdetergents.2．氮和磷。以各種形式〔有機(jī)的和無(wú)機(jī)的存在于來(lái)自人類(lèi)排放的廢物,和含磷的清潔劑。3.Carbonatesandbicarbonates?.Normallypresentinwaterandwastesascalciumandmagnesiumsalts.3．碳酸鹽和碳酸氫鹽。通常以鈣鹽和鎂鹽的形式出現(xiàn)在水和廢物中。4.Toxicsubstances.Arsenic,cyanide,andheavymetalssuchasCd,Cr,Cu,Hg,Pb,andZnaretoxicinorganicswhichmaybefoundinindustrialwastes.4．有毒物質(zhì)。砷,氰化物和在工業(yè)廢水中可以找到的有毒無(wú)機(jī)物：Cd〔鎘、Cr〔鉻、Hg〔汞、Pb〔鉛、Zn〔鋅等重金屬。Inadditiontothesechemicalconstituents,theconcentrationofdissolvedgases,especiallyoxygen,andthehydrogenionconcentrationexpressedaspHareotherparametersofinter-estinwastewater.除了這些化學(xué)成分,溶解氣體的濃度,尤其是氧氣,用pH值所表示的H離子的濃度也是其它引起廢水注意的指標(biāo)。Organicmatter.有機(jī)物Proteinsandcarbohydrates?constitute90percentoftheorganicmatterindomesticsewage.生活污水中的有機(jī)物90％是由蛋白質(zhì)和碳水化合物組成。Thesourcesofthesebiodegradablecontaminantsincludeexcretaandurinefromhumans;foodwastesformsinks;soilanddirtfrombathing;washing,andlaun-dering;plusvarioussoaps,detergents,andothercleaningproducts.這些可生物降解的物質(zhì)包括人類(lèi)的尿和排泄物、洗滌槽的食物殘?jiān)⑼梁拖丛璧呐K物、洗衣用水和洗燙水,及各種肥皂、洗潔精和其他清潔產(chǎn)品。Variousparametersareusedasameasureoftheorganicstrengthofwastewater.各種指標(biāo)用來(lái)衡量廢水中有機(jī)物濃度。Onemethodisbasedontheamountoforganiccarbon<totalorganiccarbon,orTOC?>presentinthewaste.一種方法是基于廢水中的有機(jī)碳的總量〔即總有機(jī)碳TOC。TOCisdeterminedbymeasuringtheamountofC02producedwhentheorganiccarboninthesampleisoxidizedbyastrongoxidizerandcomparingitwiththeamountinastandardofknownTOC.總有機(jī)碳是由樣品中有機(jī)碳被強(qiáng)氧化劑氧化成二氧化碳的數(shù)量與已知的總有機(jī)碳的標(biāo)準(zhǔn)數(shù)量的比較所決定的。Mostoftheothercommonmethodsarebasedontheamountofoxygenrequiredtocon-verttheoxidizablematerialtostableendproducts.常見(jiàn)的另一種方法是根據(jù)把氧化物轉(zhuǎn)化成穩(wěn)定的最終產(chǎn)物所需要的氧氣。Sincetheoxygenusedisproportionaltotheoxidizablematerialpresent,itservesasarelativemeasureofwastewaterstrength.ThetwomethodsusedmostfrequentlytodeterminetheoxygenrequirementsofwastewateraretheCOD?andBOD?tests.因?yàn)樾柩趿空扔谖鬯鞋F(xiàn)存的氧化物,它可以用于廢水濃度的相對(duì)衡量。通常確定廢水需氧量的兩種方法是COD〔化學(xué)需氧量和BOD〔生化需氧量的測(cè)定。TheCOD,orchemicaloxygendemand,ofthewastewateristhemeasuredamountofoxygenneededtochemicallyoxidizetheorganicspresent;theBOD,orbiochemicaloxygendemand,isthemeasuredamountofoxygenrequiredbyacclimatedmi-croorganismstobiologicallydegradetheorganicmatterinthewastewater.化學(xué)需氧量,是用化學(xué)方法氧化有機(jī)物的需氧量。而生化需氧量,是通過(guò)適應(yīng)環(huán)境的微生物的以生物的方式降解廢水中的有機(jī)物的需氧量。BODisthemostimportantparameterinwaterpollutioncontrol.Itisusedasameasureoforganicpollution,asabasisforestimatingtheoxygenneededforbiologicalprocesses,andasanindicatorofprocessperformance.在水污染控制理論中,生化需氧量是最重要的參數(shù)。生化需氧量用于測(cè)定有機(jī)物污染,是評(píng)估生物反應(yīng)需氧量的基礎(chǔ)和反應(yīng)過(guò)程的指標(biāo)。Theamountoforganicmatterinwaterorwastewatercanbemeasureddirectly<asTOC,forexample>,butthisdoesn'ttelluswhethertheorganicsarebiodegradableornot.我們可以直接地測(cè)定水或者廢水中的有機(jī)物含量〔例如測(cè)定總有機(jī)碳,但是這并不能告訴我們有機(jī)物是否有被生物降解。TomeasuretheamountofbiodegradableorganicsCD,weuseanindirectmethodinwhichwemeasuretheamountofoxygenusedbyagrowingmicrobialpopulationtoconvert<oxi-dize>organicmattertoC02andH20inaclosedsystem.為了測(cè)定可生物降解的有機(jī)物量,我們用一種間接的方法,也就是在一個(gè)封閉的系統(tǒng)里,測(cè)定將有機(jī)物轉(zhuǎn)化〔氧化成二氧化碳和水所用的生長(zhǎng)的微生物群的耗氧量。Theoxygenconsumed,orbio-chemicaloxygendemand<BOD>,isproportionaltotheorganicmatterconverted,耗用的氧氣,或生化需氧量,正比于有機(jī)物的轉(zhuǎn)化量,andthereforeBODisarelativemeasureofthebiologicallydegradableorganicmatterpresentinthesystem.因此,生化需氧量是系統(tǒng)中生物降解有機(jī)物的相對(duì)衡量。Becausebiologicaloxidationcontinuesindefinitely,thetestforultimateBODhasbeenarbitrarilylimitedto20days,whenperhaps95percentormoreoftheoxygenrequire-menthasbeenmet.因?yàn)樯镅趸^(guò)程可以無(wú)限次地進(jìn)行,最終生化需氧量的測(cè)定被限定為20天,這個(gè)時(shí)間能夠滿足95%或以上的微生物氧氣需求。Eventhisperiod,however,istoolongtomakemeasurementofBODuseful,但是過(guò)程時(shí)間過(guò)長(zhǎng),致使生化需氧量的測(cè)定沒(méi)有效用,soafive-daytest,BODs?,carriedoutat20°C,hasbecomestandard.所以一種五天式的測(cè)定,即將水樣置于20℃的黑暗環(huán)境五天,作為生化需氧量的標(biāo)準(zhǔn)。TherateoftheBODreactiondependsonthetypeofwastepresentandthetemperatureandisassumedtovarydirectlywiththeamountoforganicmatter<organiccarbon>present.生化需氧量的反應(yīng)速度取決于存在的廢水類(lèi)型、溫度以及假設(shè)其隨著存在的有機(jī)物〔有機(jī)碳的數(shù)量的變化趨勢(shì)。Unit14Text:WaterPurificationWatermoleculeshavenomemory,andthereforehissillytotalkaboutthenumberoftimesthatthewateryoudrinkhasbeenpollutedandrepurified,asifthemoleculesgraduallyworeout.水分子是沒(méi)有記憶力的,所以談?wù)摫晃廴竞捅粌艋娘嬘盟拇螖?shù)是沒(méi)意義的,例如分子的逐漸損耗。Allthatisimportantishowpureitiswhenyoudrinkit.而當(dāng)我們飲水的時(shí)候到底它有多純凈才是最重要的。Thepurificationofwaterhasdevelopedintoanelaborateandsophisticatedtechnology.水的凈化已經(jīng)發(fā)展為一項(xiàng)復(fù)雜的和尖端的技術(shù)。However,thegeneralapproachestopurificationshouldbecomprehensible,andinsomeca-sesevenobvious,fromageneralunderstandingofthenatureofwaterpollution.然而,污水凈化的本質(zhì)的總方法是容易理解的,在某些情況下也是明顯的。Impuritiesinwaterwereclassifiedassuspended,colloidal,ordissolved.里面的雜質(zhì)分類(lèi)為懸浮的,膠體的,或者是溶解的。Suspendedparticlesarelargeenoughtosettleoutortobefiltered.水懸浮的顆粒物是大得足夠沉降下來(lái)或者可以被過(guò)濾掉的。Colloidalanddissolvedimpuritiesaremoredifficulttoremove.膠體的顆粒物和溶解的顆粒物是更難除去。Onepossibilityissomehowtomakethesesmallparticlesjointo-gethertobecomelargerones,whichcanthenbetreatedassuspendedmatter.一是可以用某些方法使小的顆粒物結(jié)合起來(lái)變成大的顆粒物,然后把大的顆粒物作為懸浮物來(lái)進(jìn)行處理。Anotherpossi-bilityistoconvertthemtoagasthatescapesfromthewaterintotheatmosphere.Whatevertheapproach,itmustberememberedthatenergyisrequiredtoliftwaterortopumpitthroughafilter<D.二是可以把它們轉(zhuǎn)換為氣體,從水中排放到大氣中。不論采取哪一種方法,必須記住,提升水或用泵將水輸送到通過(guò)過(guò)濾床都需要能量。Withtheseprinciplesmmind,considertheproceduresusedinpurifyingmunicipalwastewaters.以上面原則作為依據(jù),來(lái)考慮用來(lái)凈化城市廢水的程度。Thefirststepisthecollectionsystem.第一步是收集系統(tǒng)。Waterbornewastesfromsourcessuchashomes,hospitals,andschoolscontainfoodresidues,humanexcrement,paper,soap,de-tergents,dirt,cloth,othermiscellaneousdebris,and,ofcourse,microorganisms.Thismixtureiscalledsanitaryordomesticsewage.水中的廢物有各種各樣的來(lái)源,例如家庭的,醫(yī)院的,學(xué)校的含有食品的殘余物,人類(lèi)的排泄物,紙,肥皂,清潔劑,臟物,布,其他各種各樣的雜物,當(dāng)然還有微生物。這種混合物就叫做生活污水。<Theadjective"sanitary"isratherinappropri-atebecauseithardlydescribestheconditionofthesewage;itpr_esumablyreferstothatofthepremiseswhosewasteshavebeencarriedaway>.〔"生活污水"這個(gè)形容詞是很不合適的,因?yàn)樗鼪](méi)有描述污水的情況；它可能是指那些廢物排放出來(lái)的地方。Thesewaters,whicharesometimesjoinedbywastesfromcommercialbuildings,byindustrialwastes,andbytherunofffromrain,flowthroughanetworkofsewerpipes.這些污水有時(shí)跟商業(yè)建筑廢水,工業(yè)廢水和雨水混合在一起,一同流進(jìn)廢水的管路網(wǎng)絡(luò)里面去。Somesystemsseparatesewagefromrainwater,oth-erscombinethem.某些系統(tǒng)將雨水和生活污水分開(kāi),另一些系統(tǒng)又將兩者結(jié)合起來(lái)。Thecombinedpipingischeaperandisadequateindryweather,butdur-ingastormthetotalvolumeisapttoexceedthecapacityofthetreatmentplant,sosome1sallowedtooverflowandpassdirectlyintothereceivingstreamorriver.結(jié)合的網(wǎng)絡(luò)式是比較便宜的,而且適合干燥的天氣,但在暴雨時(shí),總的體積很容易超過(guò)污水處理廠的容量,所以某些水就允許溢流出去和直接排放到河流里面去。PrimaryTreatment?初級(jí)處理Whenthesewagereachesthetreatmentplant,itfirstpassesthroughaseriesofscreensthatremovelargeobjectssuchasratsorgrapefruits,andthenthroughagrindingmechanismthatreducesanyremainingobjectstoasizesmallenoughtobehandledeffectivelyduringtheremainingtreatmentperiod.當(dāng)生活污水到達(dá)污水處理廠時(shí),它首先通過(guò)一系列的濾網(wǎng)以除去如老鼠,葡萄柚似的大物體,和在接下來(lái)的處理時(shí)期里,通過(guò)一架磨碾機(jī)以減少剩下的物體的尺寸使其足夠小能有效地被處理。Thenextstageisaseriesofsettlingchambersdesignedtore-movefirsttheheavygrit,suchassandthatrainwaterbringsinfromroadsurfaces,andthen,moreslowly,anyothersuspendedsolids-includingorganicnutrientsthatcansettleoutinanhourorso.下一步是設(shè)置一系列的沉淀池以除去初始的粗沙,例如雨水從路面帶進(jìn)的沙子,然后,慢慢地任何其它的懸浮固體—包括在一個(gè)小時(shí)能沉淀下來(lái)的有機(jī)營(yíng)養(yǎng)物。Uptothispointtheentireprocess,whichiscalledprimarytreatment,hasbeenrelativelyinexpensivebuthasnotaccomplishedmuch.直到這個(gè)階段,稱(chēng)為初級(jí)處理,相對(duì)地便宜但并未完成凈化的程度。SecondaryTreatment?二級(jí)處理Thenextseriesofstepsisdesignedtoreducegreatlythedissolvedorfinelysuspendedorgan-icmatterbysomeformofacceleratedbiologicalaction.接下來(lái)的一系列步驟,是設(shè)計(jì)通過(guò)加速生化作用的某種形式來(lái)較大程度地減少溶解的或微小的懸浮有機(jī)物。Whatisneededforsuchdecomposi-tionisoxygenandorganismsandanenvironmentinwhichbothhavereadyaccesstothenu-trients.分解需要氧氣和微生物以及一種兩者都易接近營(yíng)養(yǎng)物的環(huán)境。Onedeviceforaccomplishingthis'objectiveisthetricklingfilter?.達(dá)到這個(gè)目標(biāo)的一種裝置是滴濾池。Inthisdevice,longpipesrotateslowlyoverabedofstones,distributingthepollutedwaterincontinuoussprays.Asthewatertricklesoverandaroundthestones,itoffersitsnutrientsinthepres-enceofairtoanabundanceofratherunappetizingformsoflife.這種裝置,長(zhǎng)管在由巖石填充而成的濾床上緩慢的旋轉(zhuǎn),通過(guò)持續(xù)地噴灑來(lái)分布這些污水。Analternativetechniqueistheactivatedsludgeprocess.另一個(gè)技術(shù)是活性污泥過(guò)程。Herethesewage,afterprimarytreatment,ispumpedintoanaerationtank,whereitismixedforseveralhourswithairandbacteria-ladensludge.廢水,經(jīng)過(guò)初級(jí)處理后,泵到一個(gè)混合空氣和含有細(xì)菌的污泥幾個(gè)小時(shí)的曝氣池。Thebiologicalactionissimilartothatwhichoccursinthetricklingfil-ter.Thesludgebacteriametabolizetheorganicnutrients;theprotozoa,assecondarycon-sumers,feedonthebacteria.生化作用與發(fā)生在滴濾池的相似。污泥中的細(xì)菌代謝轉(zhuǎn)化成有機(jī)氧物；原生蟲(chóng),作為二級(jí)消費(fèi)者,吃掉細(xì)菌。Thetreatedwatersthenflowtoasedimentationtank,wherethebacteria-ladensolidssettleoutandarereturnedtotheaerator.處理過(guò)的水流到一個(gè)含有細(xì)菌的固體沉降的沉淀池去,然后返回到曝氣池。Someofthesludgemustberemovedtomaintainsteady-stateconditions.某些污泥必須被排放以維持一個(gè)穩(wěn)定的狀態(tài)。Theactivatedsludgeprocessrequireslesslandspacethanthetricklingfilters,and,sinceitexposeslessareatotheatmosphere,itdoesnotstinksomuch.相對(duì)滴濾池來(lái)說(shuō),活性污泥需要占地少的面積,因?yàn)樗枰貧廨^小的面積,沒(méi)有發(fā)出臭味。Theeffluentfromthebiologicalactionisstillladenwithbacteriaandisnotfitfordis-chargeintoopenwaters,letalonefordrinking.生化處理所排放的廢水仍然含有細(xì)菌,和不適合排放到清潔的水源,更不用說(shuō)飲用。Sincethemicroorganismshavedonetheirwork,theymaynowbekilled.因?yàn)槲⑸锿瓿善涔ぷ?現(xiàn)在就可以殺死他們了。Thefinalstepisthereforeadisinfectionprocess,usuallychlorination.最后一步是消毒過(guò)程,一般是加氯。Chlorinegas,氯氣,injectedintotheeffluent15to30minutesbeforeitsfinaldis-charge,cankillmorethan99percentoftheharmfulbacteria.在最后排放前加入到排水15至30分鐘,就可以殺滅99%以上的有害細(xì)菌。Tertiaryor"Advanced"Treatments?三級(jí)或高級(jí)處理Althoughconsiderablepurificationisaccomplishedbythetimewastewatershavepassedthroughtheprimaryandsecondarystages,thesetreatmentsarestillinadequatetodealwithsomecomplexaspectsofwaterpollution.盡管此時(shí)的廢水已經(jīng)通過(guò)初級(jí)和二級(jí)處理,得到了相當(dāng)大程度的凈化,但是這些處理仍然不合適應(yīng)對(duì)某些水污染的復(fù)雜方面。First,manypollutantsinsanitarysewagearenotremoved.Inorganicions,suchasnitratesandphosphates,remaininthetreatedwaters;thesematerials,aswehaveseen,serveasplantnutrientsandarethereforeagentsofeu-trophication.首先,生活污水里面有很多污染物是不能清除的。無(wú)機(jī)的離子,例如硝酸鹽和磷酸鹽,仍然在處理過(guò)的水中;這些物質(zhì),正如我們所看到的,可以作為植物的營(yíng)養(yǎng)物和水體的營(yíng)養(yǎng)成分。Thetreatmentmethodsavailabletocopewiththesetroublesomewastesarenecessarilyspecifictothetypeofpollutanttoberemoved,andtheyaregenerallyexpensive.Afewofthesetechniquesaredescribedbelow.用于應(yīng)付這些麻煩廢水的處理方式是必需專(zhuān)門(mén)除去這類(lèi)污染物,而且它們一般很昂貴。如下描述幾種這些技術(shù)。1.CoagulationandSedimentation1． 混凝和沉淀Asmentionedearlierinthediscussionofbiologicaltreatment,itisadvantageoustochangelittleparticlesintobigonesthatsettlefaster.正如在生物處理的討論中我們?cè)缜疤峒暗?將小的顆粒物轉(zhuǎn)變成的大的能夠快速沉淀的顆粒物是很有好處的。Soitisalsowithinorganicpollutants.所以它跟無(wú)機(jī)污染物同樣道理。Variousinorganiccolloidalparticlesarewaterloving<hydrophilic>andthereforeratheradhesive;intheirstickinesstheysweeptogethermanyothercolloidalparticlesthatwouldotherwisefailtosettleoutinareasonabletime.各種各樣的無(wú)機(jī)膠體顆粒是喜歡水的〔親水的并且具有相當(dāng)?shù)恼掣叫裕挥捎谒鼈兊恼掣叫运鼈円黄饚ё吆芏嗥渌y以在合理時(shí)間內(nèi)沉降下來(lái)的膠體顆粒物。Thisprocessiscalledflocculation.Lime,alum,andsomesaltsofironareamongtheseso-calledflocculatingagents.這個(gè)過(guò)程被稱(chēng)為絮凝。石灰,礬和某些鐵鹽都是這些所謂的絮凝劑。2.Adsorption2． 吸附Adsorptionistheprocessbywhichmoleculesofagasorliquidadheretothesurfaceofasol-id.吸附是氣體分子或液體分子粘附到固體表面的過(guò)程。Theprocessisselective-differentkindsofmoleculesadheredifferentlytoanygivensol-id.Topurifywater,asolidthathasalargesurfaceareaandbindspreferentiallytoorganicpollutantsisneeded.這個(gè)過(guò)程是具有選擇性的—不同種類(lèi)的分子以不同的方式粘附在任何固體。對(duì)于凈化水,那些有著大的表面積并且結(jié)合傾向于有機(jī)污染物的固體是必需的。Thematerialofchoiceisactivatedcarbon,whichisparticularlyeffec-tiveinremovingchemicalsthatproduceoffensivetastesandodors.Theseincludethebiologi-callyresistantchlorinatedhydrocarbons.選擇的物質(zhì)是活性碳,它能夠特別有效地除去產(chǎn)生令人討厭的味道和臭味的化學(xué)品。這些化學(xué)品包括那些難以生物降解的氯代烴。3.OtherOxidizingAgents3． 其他氧化劑Potassiumpermanganate<KMn04>andozone<03>havebeenusedtooxidizewaterbornewastesthatresistoxidationbyairinthepresenceofmicroorganisms.高錳酸鉀和臭氧用于氧化那些抵抗空氣中微生物的氧化的水中廢物。Ozonehastheimpor-tantadvantagethatitsonlybyproductisoxygen.臭氧有一個(gè)很重要的優(yōu)點(diǎn)就是它僅存的副產(chǎn)物是氧氣。4.ReverseOsmosis4． 反滲透Osmosisistheprocessbywhichwaterpassesthroughamembranethatisimpermeabletodissolvedions.滲透是一個(gè)水通過(guò)一種不透過(guò)溶解離子的膜的過(guò)程。Inthenormalcourseofosmosis,thesystemtendstowardanequilibriuminwhichtheconcentrationsonbothsidesofthemembraneareequal.在正常的過(guò)程中,系統(tǒng)傾向于一個(gè)平衡狀態(tài),在這個(gè)平衡狀態(tài)中膜的兩邊的濃度是相同的。Thismeansthatthewaterflowsfromthepuresidetotheconcentrated"polluted"side.Thisisjustwhatwedon'twant,becauseitincreasesthequantityofpollutedwater.這意味著水從純凈的一邊流到富集污染物的一邊。這并不是我們所希望的,因?yàn)檫@個(gè)過(guò)程增加了被污染的水的數(shù)量。However,ifexcesspressureisap-pliedontheconcentratedside,theprocesscanbereversed,andthepurewaterissqueezedthroughthemembraneandthusfreedofitsdissolvedionicorothersolublepollutants.然而,假如高壓是加到富集污染物的一邊,這個(gè)過(guò)程可被逆轉(zhuǎn),純凈水就被擠壓通過(guò)這個(gè)膜,并且這樣就除去了溶解的離子或者其他溶解的污染物。Selectedfrom"]onathanTurk,AmosTurk.EnvironmentalScience,ThirdEdition,SaundersCollegePublishing,TheDrylenPress,USA,1984"ReadingMaterial:PrinciplesofWastewaterTreatmentEffluentRequirements流出物要求Theprimaryob