专业英语PPTUnit13

WATERSUPPLY小组成员：梁爽唐北怀柏丰立曹宏利•Totalwaterdemandonamunicipalwatersupplysystemisthesumofalltheindividualdemandsduringastatedperiod.•城市供水系统的总需水量是在某段时间内个人用水的总和。WATERQUALITYREQUIREMENTSWaterDemand•Waterdemandinaparticularcommunityisnormallyspecifiedintermsofaveragedailydemand,definedasfollows:•Averagedailydemand=totalwateruseinoneyear/365days.•Unitsarem3/dormillionm3/d,orgallonsperday,ormilliongallonsperday.•某社区需水量是按照日均需水量规定的，具体如下：•日均需水量=一年总需水量/365天•单位是m3/d或者百万m3/d，或者加仑每天，百万加仑每天•Itisoftenconvenienttoexpresstherateofdemandperperson:Averagedailydemand=Averagedailydemandincommunity/midyearpopulationincommunity.Theunitsheremaybelittersperpersonperdayorgallonsperpersonperday.•人均需水量也很好描述:日均需水量=社区平均日需水量/年中社区人数。在这单位是每人/天/升或者是每人/每天/加仑。•Thedemandsonawatersystemvarynotonlyfromyeartoyearandfromseasontoseason,butalsofromdaytodayandhourtohour.•需水量是由于每年、每个季节、甚至是每天每时而各不相同的。FluctuationsinWaterUseWATERQUALITYSTANDARDS•Watercontainsavarietyofchemical,physical,andbiologicalsubstanceswhichareeitherdissolvedorsuspendedinit.•水中含有各种化学、物理、生物物质，其中有的溶解或悬浮在水中。•Waterisevaluatedforqualityintermsofitsphysical,chemical,andmicrobiologicalproperties.Itisnecessarythatthetests,usedtoanalyzethewaterasregardseachoftheseproperties,produceconsistentresultsandhaveuniversalacceptance,sothatmeaningfulcomparisonwithwaterqualitystandardscanbemade.水质评价包括物理、化学、微生物学特性。这种标准用来分析上述特性是很重要的，并且分析结果是得到大众认可的，所以与水质标准比较是有重大意义的。•Tastes,odors,color,andturbidityarecontrolledinpublicwatersuppliespartlybecausetheymakedrinkingwaterunpalatable,butalsobecauseoftheuseofwaterinbeverages,foodprocessing,andtextiles.•公共供水对水的味道，气味，颜色和浊度都有控制，因为这些因素会让水变味，不仅而此，也因为水在饮料、食品加工和纺织品中的用途所以对水的各方面都有严格管控。PhysicalCharacteristics•Themanychemicalcompoundsdissolvedinwatermaybeofnatureorindustrialoriginandmaybebeneficialorharmfuldependingontheircompositiomandconcentration.•溶解在水中的许多化合物可能是天然的或工业来源的，也可能是有益的或有害的，这取决于它们的组成和浓度。ChemicalCharacteristics•Syntheicorganiccompounds,likeDDT,whichareproductsorbypproductsofchemicalsusedinagricultureandindustry,canbuilduptotoxiclevelsinwaterandlivingorganisms.•合成有机化合物，如DDT，它们是农业和工业中使用的化学品的产物或副产物，可在水和活生物体中积累到毒性水平。SOURSESOFWATER•Thequalityandquanlityofwaterfromsurfacewaterandgroundwater,thetwomainsourses,areinfluencedbygeography,climate,andhumanactivities.•地表水和地下水（两个主要来源）的水质和数量受地理，气候和人类活动的影响。•Groundwateriswaterthathaspercolateddownwardfromthegroundsurfacethroughthesoilpores.Thereisgrowingconcernthatvaststretchesofproductivefarmsmayloseirrigationwateraswellsdodry.地下水是从地表通过土壤孔隙向下渗透的水。人们越来越担心，大量的生产性农场可能会因为井干而失去灌溉水。•Surfacewatersfromriversandlakesareimportantsourcesofpublicwatersuppliesbecauseofthehighwithdrawalratestheycannormallysustain.Seawater,availableinalmostunlimitedquantities,canbeconvertedintofreshwaterbyanumberofprocesses.•来自河流和湖泊的地表水是公共供水的重要来源，因为它们通常可以维持高的使用率,几乎无限数量的海水可以通过一些过程转化为淡。•Desalinationisthegeneraltermusedfortheremovalofdissolvedsaltsfromwater.Electrodialysisinvolvesforcedmigrationofchargedionsthroughcation-permeableoranion-permeablemembrancesbyapplyinganelectricpotentialacrossacellcontainingmineralizedwater.•脱盐是用于从水中除去溶解盐的一般术语。电渗析涉及通过在含有矿化水的细胞上施加电势来强制迁移带电离子通过阳离子可渗透或阴离子可渗透的膜。•Reclaimedwastewaterreferstowaterthathasbeentreatedsufficientlyfordirectreuseinindustryandagriculture,andforlimitedmunicipalapplications.•回收废水是指已经被充分处理已在工业和农业中直接再利用以及用于有限的市政应用的水。•Allowingwatertocleanseitselfbypercolatingthroughsoilisanothertechniquethatremovesimpuritiesfromandhaswideapplicationinrecharginggroundwatersupplies.•允许水通过渗透通过土壤来达到清洁去除杂质，这种技术对地下水供应的充电具有广泛的应用。Thanksforyourlistening！