土木工程专业英语课件.ppt

Lesson5EnvironmentalEngineering环境工程,Newwordsandphrases:perturbationecosystemsubdisciplinedepletionanaerobicscumgreasecoagulationsedimentationemanatecolloidalfiltrationpesticideherbicidefertilizercentrifugeaquiferimpoundmentozonecarcinogeniceutrophicalgaerunoffrefusedisposal垃圾处理by-product副产品,出乎意料的结果dealwith安排,处理,涉及,Environmentalengineeringisabranchofengineeringthatisconcernedwithpollutionbythestructures,machines,systems,andprocessesthatareinvolvedinhumanactivities.环境工程是和结构、机械、系统，以及涉及到人类活动的过程所产生的污染有关的一个工程学的分支。ThedevelopmentofcivilizationhascausedperturbationofmuchoftheEarthsecosystem,resultinginpollutionoftheair,landandwater.文明的发展已经引起许多地球生态系统的紊乱，造成空气、陆地和水的污染。Itisthetaskoftheenvironmentalengineernotonlytodesignsystemstoassuagethispollutionbutalsotoeducatepeopleinprotectingtheirsurroundingsfromadditionalpollution.环境工程师的任务不仅是设计出一些系统来减轻这个污染，而且还要教育人们保护他们周围的环境免遭额外的污染。Thepracticeofenvironmentalengineeringisdividedintovarioussubdisciplines.环境工程专业又被分为了不同的分支学科。,Environmentalengineering环境工程,Inmanycases,rivers,lakes,andoceanshavebecomepollutedfromdischargesofliquidwastesfromresidential,commercial,andindustrialsources.在许多情况下，河流、湖泊和海洋已经被由住宅、商业、和工业源点排放的废液所污染。Manyofthesebodiesofwaterhavebeenreclaimedbecauseofamovementinthe1970stoconstructnewwastewatertreatmentfacilitiesandtoimproveoldones.许多这些水体已经被回收了是因为20世纪70年代的一场修建新的废水处理设施和改进旧的设施的运动。Bothphysical-chemicalandbiologicalprocessesareusedtoremovefromtheliquidwastewaterstream.可以采用物理化学方法和生物学方法从废液中除去污染物。,Watertreatmentanddisposal水处理,Itisthisorganicmatterthatcausesadepletionofoxygeninriversandlakes,withconsequentanaerobicconditionsleadingtofishkillsandnoxiousodors.正是这种有机物会使江河湖泊中的氧气耗尽，形成导致鱼类死亡的厌氧环境并产生有害气体。Thephysical-chemicalandbiologicalprocessesremoveanabundanceoftheorganicmatteralongwithfloatablescumandgreasefromthewastestream.物理化学方法和生物学方法消除了大量的有机物质连同来自废水中的漂浮的浮渣和油脂。Chemicaldisinfectioninactivatesbacteria,viruses,andprotozoainthewastestream.化学消毒可使废水中的细菌、病毒和原生动物钝化。Thephysicalandchemicalprocessesusedforremovingsolidsfromthewastestreamincludescreening,sandandgritseparation,chemicalcoagulation,andplainsedimentation.用来除去废水的固体化学物的物理和化学方法包括过筛、砂和粗砂分离、化学凝结和简单沉淀。,Watertreatmentanddisposal水处理,Biologicalprocessesincludeactivatedsludge,contacttowers,andbiologicaldiscs.生物学方法包括活性污泥、接触塔和生物圆盘。Theapplicationofthesetreatmentprocessestoresidential,commercial,andindustrialwastewatershasreducedthepollutionalloadonmanyrivers,lakes,andharbors.这些处理方法应用到住宅、商业和工业废水上，已经降低了许多河流、湖泊和海港的污染程度。Theredoremain,however,casesoflargemetropolitanareasthathavenotcompletetheirclean-upcampaigns,andinmanyotherregionsdischargesofuntreatedmixturesofsanitarywastesandstormwatersoccurduringheavyrains.然而，仍然有部分大城市没有完成它们的卫生大扫除活动，在许多其他地区，暴雨期间未经处理的生活污水和雨水的混合液随意排放。,Watertreatmentanddisposal水处理,Thesedischargesemanatefromlargeconduitsthatcarrybothsanitaryandstormwastes.这些排放物来自于输送生活污水和雨水的管道。Theimpuritiesthatrunoffthelandduringastormmixwiththesanitarywastesinthepipes,andthequantityofwastewaterovertaxesthecarryingcapacityoftheconduits；aportionofthismixtureflowsintothenearestbodyofwaterbeforeitcanreachthewastewatertreatmentfacility.在暴雨期间，陆地上的杂质和管道中的生活污水混和在一起，废水的数量超过了管道的输送能力，混合物的一部分在到达废水处理设施前就流进了附近的水体。Itisusuallytooexpensivetoconstructawholenewsetofseparatesanitaryconduits;通常，由于成本太高而不能修建一整套新的单独生活污水管道；,Watertreatmentanddisposal水处理,however,somecities,likeChicago,havebeguntosolvetheproblembyconstructingasystemofdeepundergroundtunnelsthatstorethelargequantitiesofdischargesduringthestorm,followingwhichthewastewaterscanbebledintothetreatmentfacilitiesatreasonablerates.然而，有些城市，像芝加哥，已经开始修建一个深埋的地下隧道系统来解决这个问题，该系统可以存储暴雨期间的大量排出物，这样废水就能以一个合理的速度流进处理设备。Wherewastewatermustbedischargedintolakesanddrystreams,ahigherleveloftreatmentmustbeemployed,includingremovalofnutrientsandcolloidalmatter.在那些废水必须被排入湖泊和干河的地方，必须采用更高水平的处理措施，包括营养物和胶质物的去除。Physical-chemicalandbiologicaltreatmentprocessesareemployedasforwastewatertreatment.物理化学和生物处理方法被用来处理废水。,Watertreatmentanddisposal水处理,Inaddition,chemicalsareintroducedforprecipitationofnutrients,followedbycoagulationandfiltrationforremovingsolidsremainingafterbiologicaltreatment;andinsomecasesgranularactivatedcarbonormembranefiltrationisusedforadditionalpurificationofthewastestream.此外，化学药品被用来进行营养物的沉淀，接下来，采用凝结和过滤法来消除生物处理后的固体残留物；在某些情况下，颗粒状活性炭或薄膜过滤被用于污水河流的补充净化。Thishigherleveloftreatmentisadvisablebecauseofthedamagethatanyvisualtracesofwastescandototheappearanceofthewaters.宜采用高水平的处理方法，因为任何可见的垃圾遗迹都会对水体外表造成损害。Inaddition,thetreatmentmaycombatthepotentialeutrophiceffectthatthenutrientsphosphorusandnitrogencanhaveonthereceivingwaters.此外，这种处理可以抑制营养物磷和氮对流进水体的潜在营养促进效应。,Watertreatmentanddisposal水处理,Wherewastewaterdischargesintoriversfromwhichdrinkingwateristakendownstream,specialattentionisgivennotonlytotheremovaloforganicmatterfromthewastesbutalsotothedisinfectionprocessesthatinactivatemicroorganisms.在废水排入河流处的下游汲取饮用水，不仅要特别注意废水中有机物的清除，而且要注意钝化微生物的消毒处理。Alsoofconcernaredischargesoforganicchemicalcontaminantsfromindustryorrunofffromfarmlandsalongtherivercontaminatedbypesticidesandherbicides.还要关心的是工厂有机化学污染物的排放或沿河农田被杀虫剂和除草剂污染的水流。Theindirectreuseofwastewaterthathasbeendischargedintoriversiscommonaroundtheworld,anditisacceptableaslongasthedischargesaretreatedproperlyandcontaminationfromorganicchemicalsisavoided.世界上比较普遍的是对排入河川废水进行间接的重复利用，只要排放物经过适当的处理，并且有机化学污染物被消除，它是可以被接受的。,Watertreatmentanddisposal水处理,Lessacceptableisthedirectreuseofwastewaterforpotableuse,evenafterahighleveloftreatment.即使经过高标准处理的废水直接再用作饮用水仍然是很难被接受的。Ofmostconcernhereisthepossibilityofoutbreakofdisease.这里人们关心得最多的是爆发疾病的可能性。However,somenations,suchasIsrael,dopractice,outofnecessity,reusebystoringwastewatersforlongperiodsoftimeinmaturationpondspriortochemicalandphysicaltreatment.然而，有些国家，比如以色列，实际上并不是出于必要，在采用化学和物理方法处理之前，将废水储存在熟化池中很长一段时间然后再利用。,Watertreatmentanddisposal水处理,Ithasbecomequitecommonandacceptable,especiallyindrierclimates,toreusewastewater,followingarespectableleveloftreatment,forirrigationofcropsandforwateringgolfcourses.特别是在比较干燥的气候条件，废水经过一个高质量标准的处理后再用来灌溉庄稼和给高尔夫球场洒水这种做法已经非常普遍和认可。Inaddition,certaincommunitiessuchasNaples,Florida,andIrvine,California,haveconstructeddualwatersystems,usingtreatedwastewaterforoutdoorresidentialandcommercialuseandforfirefighting,whilesavinghigher-qualitywaterforportableuse.此外，某些地方，如那不勒斯、佛罗里达、伊尔文和加利福尼亚，已经修建了双重水系统，处理过的水可用于户外的民用和商业用水，以及消防用水，同时储存更高质量的水供饮用。Inothercases,largeindustriestakewatersdirectlyfromriversforthecoolingofindustrialprocesses.其他情况下大型工厂直接从河里取水用于工业加工的冷却。,Watertreatmentanddisposal水处理,Theorganicandinorganicsolidsthatareremovedfromwastewaterbythephysical-chemicalandbiologicalprocessesmustbedewatered,stabilizedbiologicallyorchemically,andthenplacedinacontrolledlandfill,burnedorcompostedforreturntotheland.通过物理化学和生物方法从废水中清除的有机和无机固体物质必须经过脱水和生物或化学稳定，然后置于一个受控的垃圾填埋场，燃烧或堆肥，再回到土地中。Therearesomecircumstancesinwhichthesolidsdonothavetobedewateredbutcanbeapplieddirectlytotheland,followingbiologicalstabilization.有些境况下，固体物质不必经过脱水就能直接被土地利用，其后是生物稳定过程。,Wastewatersolidstreatmentanddisposal废水固体物质处理,Therearealsoinstances,suchasinMilwaukee,Wisconsin,wherethesolidsareprocessedintoafertilizer.也有一些例子，比如在密尔沃基市、威斯康星州，固体物被加工成了一种肥料。Unfortunately,inmanypartsoftheworld,includingtheeastcoastoftheUnitedStates,thewastesolidsareneitherreclaimedtothelandnorburnedasasourceofenergy.不幸的是，在世界上的许多地方，包括美国的东海岸，固体废料既没有被回收进土地，也没有作为一种能源燃烧。Theyarebargedorpipedouttoseaandthendumpedintothewater.它们被用驳船或管道运出大海，然后倒进水里。Itisanticipatedthatthispracticewillbediscontinued,andincinerationforenergyrecoveryalongwithcompostingforreuseonthelandwillreplaceoceandumping.我们期待这种做法将被废止，焚化供能源回收和堆肥供土地再利用将取代海洋倾弃的做法。,Wastewatersolidstreatmentanddisposal,Wherethesolidsarecomposted,heavyandtoxicmetalsmustberemovedattheirsource.在固体废料堆肥的地方，重金属和有毒的金属必须彻底地清除。Theprocessesemployedfortreatingwastewatersolidsincludedewateringpresses,belts,andcentrifuges,aswellasfluid-bedfurnaces.用来处理废水固体物的方法包括挤压脱水法，传送带及离心脱水法，还有流化床熔炉法。Anotherprocessthathasreceivedconsiderableattentionisinvesselcomposting.另一种已经受到相当关注的方法是容器堆肥。,Wastewatersolidstreatmentanddisposal,Theindiscriminatedumpingoftrashandgarbageonlandhascausedseriouspollutionproblems.地上的垃圾和废料不加区别地倾倒已经导致了严重的污染问题。Refusedisposalcanbecontrolledinawell-designedand-operatedlandfill,andthiscanbeasuitableprocessforcertainsmallcommunities.在一个设计得好又操作得好的垃圾填埋场，垃圾处理能加以控制，这对于某些小地方可能是一个恰当的方法。However,landforthedisposalofrefuseformid-andlarge-sizecommunitiesisbeingseriouslyreduced,andcompostingofrefuseforreuseonthelandmayhavelimitedapplication.然而，在一些大中城市，用作垃圾处理的场地正在严重地减少，在土地上进行垃圾堆肥再利用就受到了限制。,Refusedisposal垃圾处理,Theappropriatesystemforthemajorityofcommunitiesappearstobeincinerationoftherefuse,withrecoveryoftheenergyfromtheburningoforganicmaterials.对于大多数地方，适当的体系好像就是垃圾焚烧了，通过有机物质的燃烧来回收能量。Theairemissionsystemsfromthesethermalreactors,aswellasfromthefurnacesthatburnsolidsemanatingfromwastewaterplants,mustbedesignedtopreventchemicalandparticulateairpollution.源于热反应堆及污水厂固体废料焚烧炉的空气散发系统必须设计成能够防止化学品和微粒子空气污染。Theseairemissionsystemsincludeelectrostaticprecipitatorsandafterburners.这些空气散发系统包括静电除尘器和加力燃烧室。,Refusedisposal垃圾处理,Unfortunately,countrysidesandgroundwatershavebecomeclutteredandpollutedbylong-termillegaldumpingandwashingsfromindustrialandcommercialactivities,aswellasfrompublicagencies.不幸的是，由于来自工业和商业活动以及公众机构的长期非法倾卸和洗涤，乡间和地下水已经变得混乱并且被污染。Theremovalofstoredcontainersofwastesfromthedumpinggroundsisnecessarilyaslowprocess,andanapproveddisposalsitemustbedevelopedandcontained.垃圾堆积场中废料储存坑的搬迁应缓慢进行，一个核准的处理场地必须加以开发并包含在内。Thecleaningofcontaminatedsoilsandgroundwatersisanevenslowerprocess,andthetechnologyfordecontaminationmustbeproperlydesignedandputintoplace.对已经污染的土壤和地下水进行净化是一个更慢的过程，清除污染的技术必须要恰当地设计和投入使用。,Hazardouswastedisposal危险性废物处理,Forexample,waterscontaminatedwithorganicchemicalsareslowlypumpedfromtheaquifer,andthenthecontaminantsareremovedeitherbyair-strippingoradsorptionontogranularactivatedcarbon.比如，被有机化学物污染了的水被慢慢地从含水土层中抽出来，然后通过空气清洗或粒状活性炭吸附作用清除污染物。Thecleansedwaterisinjectedbackintotheaquifer,andthisprocesscantakeyearstoaccomplish.净化了的水再被注回到含水土层中，这个过程要花数年时间才能完成。Thiscanbeinconvenientand,insomecases,adangertohealthforcommunitiesthatmustusethesegroundwatersfortheirpotablewatersupply.某些情况下这种做法可能会造成不便，对于那些必须使用地下水作为饮用水供应的居民健康是一种威胁。,Hazardouswastedisposal危险的废物处理,Totheenvironmenthasbeenaddedsmokefromdiesel-driventrucks,uncontrolledgasolineengineemissions,andpollutionfromindustrialsmokestacks.柴油驱动的卡车和不受限制的汽油机使环境中废烟增加，工业烟囱则带来污染。IntheUnitedStates,statisticspublishedbytheEnvironmentalProtectionAgencyin1987revealedthat2.4109lboftoxicchemicalsarereleasedintotheairannually,while100millionpeoplelivewhereotherairpollutants,chieflyfromautomobiles,exceedfederalstandards.在美国，由环保机构1987年公布的统计资料显示，每年有2.4亿磅的有毒化学物质被排放进了空气中，同时，有1亿人居住在其他空气污染物（主要来自汽车）超过联邦标准的地方。Localsmoginmetropolitanareas,suchasLosAngeles,iscausedbytheactivitiesoftherespectivecommunities.在大城市的局部烟雾，比如洛杉矶，是由各个社区的活动造成的。,Air-pollutioncontrol空气污染控制,AcidraincausedbytheemissionsofgasesfromtheindustrialsmokestacksofthemidwesternUnitedStatesfailsontheforestsandlakesoftheNortheastandCanada.由美国中西部的工业烟囱排放的气体导致的酸雨降落在美国的东北部和加拿大的森林和湖泊上。Therehavebeenattemptsatcleaninguptheair,buttheactiontowardsolutionhasbeenlimited.虽然已经做了很多空气净化的尝试，但是寻求解决方法的行动还是受到很大的限制Thetechnologyisavailable(forexample,multiple-hearthandfluid-bedreactorsalongwithsophisticatedairemissionstechnology)forremovingtheparticulatematterandthecontaminatingchemicalsfromtheairemissions；buttheprocessesareexpensive,andtheprogressisslow.用于清除空气中粒状物质和化学污染物的技术是可用的（比如，各式各样的炉床和流化床反应器，以及尖端的空气发射技术）。但是这些方法的代价昂贵，而且进度缓慢。,Air-pollutioncontrol空气污染控制,Theavailabilityofdrinkingwaterthatissafeandofgoodqualityisanimportantfactorinmoderncivilization.安全高质量的饮用水的可用性是现代文明的一个重要因素。Sources来源Indirectuseofwastewaterbywithdrawingdrinkingwaterfromriversisaviableandeconomicalwaytosupplycommunitieswithpotablewater,especiallythoselocatedonwaterfronts.从河川汲取饮用水给社区的间接利用废水的方法是可行的和经济的，特别是对于滨水地区的社区。Thewatermustbedisinfectedfortheinactivationofmicrobiologicalpollutants,andphysicalandchemicaltreatmentmustbeprovidedfortheremovaloforganicandinorganicimpurities.这水必须被消毒以钝化微生污染物，并且必须进行物理和化学处理以消除有机和无机杂质。,Potablemanagement饮用水管理,Othersourcesofdrinkingwaterarenaturallakesandimpoundmentsofrivers.饮用水的其他来源是自然湖泊和人工湖。Theseareusuallyofbetterqualitythanriverwaters,andtheycanbeusedformultiplepurposessuchaswatersupplyandhydroelectricpower.这些水的质量通常比河中的水要好，它们能被用于双重目的，比如水供应和水力发电站。Controlledrecreationaluseofsectionsoftheselakesisnotunusual.这些湖泊的部分区域作为受控的娱乐性用途使用并非不寻常。Undergroundaquifersareacommonsourceofdrinkingwater,andtheirqualityisveryhigh,exceptwherechemicalcontaminationhasoccurred.地下含水土层是饮用水的普通来源，并且水质非常好，除了那些发生过化学污染的地方。,Sources来源,Insomepartsoftheworld,aquiferscanberechargedwithreclaimedsurfacewaters.在世界上的某些地方，蓄水层可利用回收地表水进行回灌。Aseriousprobleminmanypartsoftheworldistheshortageofpuredrinkingwaterduringperiodsoflowrainfallandsnow.AmajordroughtoccurredontheeasternseaboardoftheUnitedSatesinthespringof1989.世界上许多地方的一个严重的问题是在低降雨量和降雪量期间纯净饮用水的短缺。1989年春天，美国东部沿海地区发生了一场大规模旱灾。Thereappeartobetworeasonsforwatershortagesduringdroughts：Manydrinking-watersupplysystemshavenotbeenplannedtodealadequatelywithdroughts,andwateriswastedbecauseofitsrelativelylowprice.干旱期间缺水似乎有两个原因：许多饮水供给系统没有能计划充分以应对旱灾，相对低的水价又使大量水被浪费。,Sources来源,Itisprudenttoselectthepurestwateravailablefordrinkingpurposes.要谨慎选择可利用水中最纯净的水作为饮用用途。Thiscanbeundergroundwater,springs,oruplandlakes.这可能是地下水、泉水或高地的湖泊。Itthenbecomesimperativetoprotectthatsource.因此，保护这些水源就变得很迫切了。Preventionofchemicalcontaminationofgroundwatersisextremelyimportant,asisthejudiciouscontroloftheuseofthebanksofasurfacewater.防止地下水受到化学污染非常重要，就像明智地控制河岸地表水的使用一样。Lakescanbeusedforrecreationaswellasforawatersource;however,suchmixeduserequiresgoodplanning.湖泊可以被用作娱乐，也可作为水源，但是，这种混和利用需要有好的规划。,Quality质量,Thepurificationofwatersupplyisjustasimportantaswatershedplanningandcontrol.给水的净化和分水岭的规划控制一样重要。Wherethequalityofthesourceisdecenttostartwith,chemicaldisinfection,coagulation,andfiltrationisadequate.源头处水源质量相当好的那些地方，化学消毒、凝结和过滤就足够了。Ifwaterisbeingtakenfromariversupplythatismuddyandsubjecttoorganicpollution,additionaltreatmentisrequired.如果水是从泥泞的河中或遭受过有机物污染的河中汲取的，则需要额外的处理。Greatstridesweremadeinthe1980sinthedevelopmentofwaterpurificationtechnology.20世纪80年代，净水技术取得了重大的发展。,Quality质量,Ozonehasbecomethechemicaldisinfectantofchoicebecauseitisthemostpotentdisinfectantforbacteria,viruses,andprotozoa；andunlikechlorine,itdoesnotformcarcin