专业英语词汇及课文选段

Watersupply&drainageengineeringspecializedEnglish给水排水工程专业英语Schoolofcivil&transportationengineering土木与交通工程学院Facultyofmunicipalpublicequipment城市公用设备系High-risebuilding高层建筑Advancedwatertreatmentprocessing深度水处理工艺Waterqualitymonitoring水质监测Strongabsorption很强吸附能力Remove去除Waterresources水资源Naturalorganic天然有机物Conventionalwatertreatment常规水处理工艺Domestic生活waterpollution水污染wastewater废水Industrial工业recognition意识freshwater淡水资源Drawlots抽签waterdemand需水量Unbalanceecologicalenvironment生态环境不平衡Purifiedwater纯净水urban城镇accountfor占有…的比例Toprotectwaterenvironmentisourresponsibility保护水环境我们的责任Waterresourcesandwatercrisis水资源与水危机Watershortage水资源短缺flowchart流程图collidewith与…碰撞breakdown衰竭Groundwatersupplies地下水供应surfacewatersupplies地表水供应precipitation降雨waterwithdrawals水消失水撤退Ahighrateofwateruse高耗水率intake取水Globalwatercrisis全球水危机characteristicresidencetime特征停留时间potable可饮用的fungi真菌secretion分泌液Activatedcarbon活性炭chlorinedioxide二氧化氯Break–pointchlorination折点加氯high–efficient高效的Ozone臭氧aeration曝气aggregate聚集凝聚coagulation凝结Stable稳定的destabilize脱稳flog絮体gravityforce重力Directfiltration直接过滤deposit沉积物supplypipenetwork给水管网turbidity浊度sedimentation沉淀池wateranalysis水质分析color色度colloidalorganicmatter胶态有机物domesticpurposesuse家庭用水giveriseto引起导致powderactivatedcarbon活性炭Tap开关、龙头aquifer含水层蓄水层watertable地下水位Extraction抽取取出提取萃取precipitation沉淀沉积物，沉降Runoff径流流量流出口决赛evaporation蒸发transpiration蒸发散发蒸腾作用sleet冰雨雨夹雪Concentration集中浓缩浓度residue残留物TDS（thetotaldissolvedsolids）总溶解性固体TSS（thetotalsuspendedsolids）总悬浮性固体filtration过滤acidic酸性的，酸的organism生物体有机体microorganism微生物alkalinity碱度DO（dissolvedoxygen）溶解氧BOD（biochemistryoxygendemand）生物需氧量Decomposable可分解的oxidation氧化stabilize稳定COD（chemicaloxygendemand）化学需氧量nitrogen氮particulate微粒颗粒biodegradable生物可降解的Wastewater废水malodorous有恶臭的dryweatherflow枯季流量Overlandflow地表径流effluent流出的discharge流量排放物Contaminant致污物preliminarytreatment预处理primarytreatment初级处理constituent构分成分secondarytreatment二级处理Tertiarytreatment三级处理chemicalprecipitation化学沉淀Anaerobic厌氧的advancedoxidation高级氧化membranefiltration滤膜breakpointchlorination折点加氯denitrification反硝化作用脱氮作用ozone臭氧colloidal胶体的胶质的advancedtreatment高级处理eutrophication富营养化作用pointsource点源Asupplyofwateriscriticaltothesurvivaloflife,asweknowit.Peopleneedwatertodrink,animalsneedwatertodrink,andplantsneedwatertodrink.Thebasicfunctionsofsocietyrequirewater:cleaningforpublichealth,consumptionforindustrialprocesses,andcoolingforelectricalgeneration.Inthislesson,wediscusswatersupplyintermsof:1groundwatersupplies2surfacewatersuppliesGroundwaterisanimportantdirectsourceofsupplythatistappedbywells,aswellasasignificantindirectsourcesincesurfacestreamsareoftensuppliedbysubterraneanwater.Nearthesurfaceoftheearth,inthezoneofaeration,soilporespacescontainbothairandwater.Thiszone,whichmayhavezerothicknessinswamplandsandbeseveralhundredfeetthickinmountainousregions,containsthreetypesofmoisture.Afterastorm,gravitywaterisintransitthroughthelargersoilporespaces.Capillarywaterisdrawnthroughsmallporespacesbymolecularforcesduringallexceptthedriestclimaticconditions.Moisture,fromthezoneofaerationcannotbetappedasawatersupplysource.Inthezoneofsaturation,locatedbelowthezoneofaeration,thesoilporesarefilledwithwater,andthisiswhatwecallgroundwater.Astratumthatcontainsasubstantialamountofgroundwateriscalledanaquifer.Atthesurfacebetweenthetwozones,calledthewatertableorphreaticsurface,thehydrostaticpressureinthegroundwaterisequaltotheatmosphericpressure.Anaquifermayextendtogreatdepths,butbecausetheweightofoverburdenmaterialgenerallyclosesporespaces,littlewaterisofwaterthatwilldrainfreelyfromanaquiferisknownasspecificyield.Surfacewatersuppliesarenotasreliableasgroundwatersourcessincequantitiesoftenfluctuatewidelyduringthecourseofayearevenaweek,andwaterqualityisaffectedbypollutionsources.Ifariverhasanaverageflowof10cubicfeetpersecond(cfs),thisdoesnotmeanthatacommunityusingthewatersupplycandependonhaving10cfsavailableatalltimes.Thevariationinflowmaybesogreatthatevenasmalldemandcannotbemetduringdryperiodsandsostoragefacilitiesmustbebuilttosavewaterduringwetterperiods.Reservoirsshouldbelargeenoughtoprovidedependablesupplies.However,reservoirsareexpensiveand,iftheyareunnecessarilylarge,representawasteofcommunityresources.MeasurementofwaterqualityQuantitativemeasurementsofpollutantsareobviouslynecessarybeforewaterpollutioncanbecontrolled.However,measurementofthesepollutantsisfraughtwithdifficulties.Sometimesspecificmaterialsresponsibleforthepollutionarenotknown.Moreover,thesepollutantsaregenerallypresentatlowconcentrations,andveryaccuratemethodsofdetectionarerequired.Onlyarepresentativesampleoftheanalyticaltestsavailabletomeasurewaterpollutionisdiscussedinthissection.Acompletevolumeofanalyticaltechniquesusedinwaterandwastewaterengineeringiscompiledasstandardmethodsfortheexaminationofwaterandwastewater.Thisvolumeistheresultofaneedforstandardizingtesttechniques.Itisconsidereddefinitiveinitsfieldandhastheweightoflegalauthority.Manywaterpollutantsaremeasuredintermsofmilligramsofthesubstanceperliter(mg/L).Inorderpublicationspollutantconcentrationsareexpressedaspartspremillion,aweight/weightparameter.Iftheliquidinvolvediswater,ppmisidenticalwithmg/L,sinceoneliter(L)ofwaterweights1000grams(g).Forpollutantspresentinverylowconcentrations(<10mg/L),ppmisapproximatelyequaltomg/L.However,becauseofthepossibilitythatsomewasteshavespecificgravitydifferentfromwater,mg/Lispreferredtoppm.Athirdcommonlyusedparameterispercent,aweight/weightrelationship.Notethat10000ppm=1%andisequalto10000mg/Lonlywhen1mL=1g.Mosttestsmaybeperformedonawatersampletakenfromthestream.Theprocess,bywhichthesampleisobtained,however,maygreatlyinfluencetheresult.Thethreebasictypesofsamplesaregrab,composite,andflow-weightedcomposite.SolidsWastewatertreatmentiscomplicatedbythedissolvedandsuspendedinorganicmaterialthewastewatercontains.Indiscussionofwatertreatment,bothdissolvedandsuspendedmaterialsarecalledsolids.Theseparationofthesesolidsfromthewaterisoneoftheprimaryobjectivesoftreatment.Strictlyspeaking,inwastewateranythingotherthanwaterisclassifiedassolids.Theusualdefinitionofsolids,however,istheresidueafterevaporationat103℃（slightlyhigherthantheboilingpointofwater）PhThepHofasolutionisameasureofhydrogenionconcentration,whichinturnisameasureofitsacidity.Thehydrogen-ionconcentrationinwaterisconnectedcloselywiththeextenttowhichwatermoleculesdissociate.Purewaterdissociatesslightlyintoequalconcentrationsofhydrogenandhydroxyl(OHˉ)icons.AlkalinityAparameterrelatedtopHisalkalinity,orthebufferingcapacityofthewateragainstacids.WaterthathasahighalkalinitycanacceptlargedosesofacidwithoutloweringthepHsignificantly.Waterswithlowalkalinity,suchasrainwater,canexperienceadropinthepHwithonlyaminoradditionofhydrogenion.DissolvedoxygenProbablythemostimportantmeasureofwaterqualityisthedissolvedoxygen(DO).Oxygen,althoughpoorlysolubleinwater,isfundamentaltoaquaticlife.WithoutfreeDO,streamsandlakesbecomeuninhabitabletogill-breathingaquaticorganisms.Theactualquantityofoxygen(othergasestoo)thatcanbepresentinsolutionisgovernedby(1)thesolubilityofthegas,(2)theconcentrationoftheimpuritiesinthewater(e.g.,salinity,suspendedsolids,etc.).Becausetherateofbiochemicalreactionsthatuseoxygenincreaseswithincreasingtemperature,dissolvedoxygenlevelstendtobemorecriticalinthesummermonths.Theproblemiscompoundedinsummermonthsbecausestreamflowsareusuallylower,andthusthetotalquantityofoxygenavailableisalsolower.Thepresenceofdissolvedoxygeninwastewaterisdesirablebecauseitpreventstheformationofnoxiousodors.Theamountofoxygendissolvedinwaterisusuallymeasuredeitherwithanoxygenprobeorbyiodometrictitration.ThelattermethodistheWinklertestsforDO,developedabout100yearsagoandthestandardagainstwhichallothermeasurementsarecompared.BiochemicaloxygendemandTherateatwhichoxygenisusedisperhapsevenmoreimportantthanthedeterminationofDO.Averylowrateofusewouldindicateeithercleanwater,thattheavailablemicroorganismsareuninterestedinconsumingtheavailableorganiccompounds,orthatthemicroorganismsaredeadordying.Therateofoxygenuseiscommonlyreferredtoasbiochemicaloxygendemand(BOD).BODisnotaspecificpollutantbutratherameasureoftheamountofoxygenrequiredbybacteriaandothermicroorganismsengagedinstabilizingdecomposableorganicmatter.Themostwidelyusedparameteroforganicpollutionappliedtobothwastewaterandsurfacewateristhe5-dayBOD.Thisdeterminationinvolvesthemeasurementofthedissolvedoxygenusedbymicroorganismsinthebiochemicaloxidationoforganicmatter.DespitethewidespreaduseoftheBODtest,ithasanumberoflimitations.Itishopedthat,throughthecontinuedeffortsofworkersinthefield,oneoftheothermeasuresoforganiccontent,orperhapsanewmeasure,willultimatelybeusedinitsplace.Why,then,ifthetestsuffersfromseriouslimitations,isfurtherspacedevotetoitinthistext?ThereasonisthatBODtestresultsarenowused(1)todeterminetheapproximatequantityofoxygenthatwillberequiredtobiologicallystabilizetheorganicmatterpresent,(2)todeterminethesizeofwaste-treatmentfacilities,(3)tomeasuretheefficiencyofsometreatmentprocesses,and(4)todeterminecompliancewithwastewaterdischargepermits.ChemicaloxygendemandAmongmanydrawbacksoftheBODtest,themostimportantisthatittakesfivedaystorun.Iftheorganiccompoundsareoxidizedchemicallyinsteadofbiologically,thetestcanbeshortenedconsiderably.Suchoxidationisaccomplishedwiththechemicaloxygendemand(COD)test.BecausenearlyallorganiccompoundsareoxidizedintheCODtestandonlysomearedecomposedduringtheBODtest,CODvaluesarealwayshigherthanBODvalued.Oneexampleofthisiswoodpulpingwaste,inwhichcompoundssuchascelluloseareeasilyoxidizedchemically(highCOD)butareveryslowtodecomposebiologically(lowBOD).TurbidityWaterthatisnotclearbut“dirty”,inthesensethatlighttransmissionisinhibited,isconsideredturbid.Inthetreatmentofwaterfordrinkingpurposes,turbidityisofgreatimportance,firstbecauseofaestheticconsiderationsandsecondbecausepathogenicorganismscanhideonthetinycolloidalparticles.Turbidityisanothertestusedtoindicatethequalityofwastedischargesandnaturalwaterswithrespecttocolloidalandresidualsuspendedmatter.Themeasurementofturbidityisbasedoncomparisonoftheintensityoflightscatteredbyasampletothelightscatteredbyareferencesuspensionunderthesameconditions.Formazinsuspensionsareusedastheprimaryreferencestandard.Theresultsofturbiditymeasurementsarereportedasnephelometricturbidityunits.Colloidalmatterwillscatterorabsorblightandthuspreventitstransmission.Itshouldbenotedthatthepresenceofairbubblesinthefluidwouldcauseerroneousturbidityreadings.Ingeneral,thereisnorelationshipbetweenturbidityandtheconcentrationoftotalsuspendedsolidsinuntreatedwastewater.Thereis,however,areasonablerelationshipbetweenturbidityandtotalsuspendedsolidsforthesettledandfilteredsecondaryeffluentfromtheactivatedsludgeprocess.FundamentalsofwastewatertreatmentEverycommunityproducesbothliquidandsolidwastesandairemissions.Theliquidwaste—wastewater—isessentiallythewatersupplyofthecommunityafterithasbeenusedinavarietyofapplications.Fromthestandpointofsourcesofgeneration,wastewatermaybedefinedasacombinationoftheliquidorwater-carriedwastesremovedfromresidences,institutions,andcommercialandindustrialestablishments,togetherwithsuchgroundwater,surfacewater,andstormwaterasmaybepresent.FuturetrendsinwastewatertreatmentIntheU.S.EPANeedsAssessmentSurvey,thetotaltreatmentplantd