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1EnvironmentalscienceandengineeringAmosThomasDemonTEAM:4082021/5/10Thesearetheidealenvironmentthatwedreamtolivein.2021/5/10Wakeup!Thesearetheenvironmentweliveinnow!2021/5/10pollutionsWaterpollution•Waterpollutionisthecontaminationofwaterbodiessuchaslakes,rivers,oceans,andgroundwater.WaterpollutionTheheavysmokepipedfromthefactorychimneys.AirpullutionAutomobileexhaustThenoisepollutionTherubbishweproducedTheWhitepollutionInmywords•Theenvironmentistheworldwelivein,andthenaturalsurroundings.•Everytimewespreadourcitys,everygarbageweproduce,everydropofwaterwepollute，wehurtour“mothernature”.•WerelyontheEarthforeverythingweneedtosurvive,solet’stakecareofit.•Wecan’tlivewithoutwater,butnowthewaterwaspolluted.Itisthebiggestproblem.Itinfluencesourdailylife.Soweshouldfindawaytosolvethisproblem.14WaterTreatmentProcesses15WaterTreatment16•Watertreatmentoperationsfulfilloneorthreekeytasks:removalofparticulatesubstancessuchassandandclay,organicmatter,bacteria,andalgae;removalofdissolvedsubstancessuchasthosecausingcolorandhardness;andremovalordestructionofpathogenicbacteriaandviruses.Theactualselectionoftreatmentprocessesdependsonthetypeofwatersourceandthedesiredwaterquality.•水处理操作完成一个或三个关键任务：去除颗粒物如沙粒和粘土、有机物、细菌和藻类，去除溶解物质如那些产生颜色和硬度的，及除去或消灭致病细菌和病毒。处理工艺的实际选择依赖于水源的类型和水质要求。17•Screeningtoremovelargesolidssuchaslogs,branches,rags,andsmallfishisthefirststageinthetreatmentofwater.Allowingsuchdebrisintothetreatmentplantcoulddamagepumpsandclogpipesandchannels.Forthesamereasons,waterintakesarelocatedbelowthesurfaceofthelakeorriverinordertoexcludefloatingobjectsandminimizephysicaldamagefromice.•格栅是水处理的第一阶段，它能去除大块固体例如木头、树枝、破布和小鱼。这些垃圾进入处理厂会损害水泵并堵塞管道。同理，入水口设置在湖泊或者河流表面以下，以排除漂浮物并最小化冰块的物理破坏。18Sedimentation•Sedimentation,theoldestandmostwidelyusedformofwaterandwastewatertreatment,usesgravitysettlingtoremoveparticlesfromwater.Itisrelativelysimpleandinexpensiveandcanbeimplementedinbasinsthatareround,square,orrectangular.Asnotedearlier,sedimentationmayfollowcoagulationandflocculation(forhighlyturbidwater)orbeomittedentirely(withmoderatelyturbidwater).•沉淀是水和废水处理中最古老和应用最广的方法，利用重力沉淀去除水中颗粒物。它相对简便、廉价，可用通过圆形、方形或者矩形的水池来实现。如前所述，沉淀池跟在混凝和絮凝（对于高度浑浊的水）或者被完全省略（中度浑浊的水）。19Coagulation/flocculation•Coagulation/flocculationisachemical-physicalprocedurewherebyparticlestoosmallforpracticalremovalbyplainsedimentationaredestabilizedandclusteredtogetherforfastersettling.Asignificantpercentageofparticulatessuspendedinwateraresosmallthatsettlingtothebottomofatankwouldtakedaysorweeks.Thesecolloidalparticleswouldneversettlebyplainsedimentation.•混凝/絮凝是一种化学物理过程，那些太小的用简单沉降法不能去除的颗粒物会在这个过程中变得不稳定形成凝块，从而能较快的沉淀。水中大部分悬浮颗粒物太小，沉淀到水池底部会用数天甚至数周。这些胶体颗粒永远不会自然沉淀。20Disinfection•Toensurethatwaterisfreeofharmfulbacteriaitisnecessarytodisinfectit.Chlorinationisthemostcommonmethodofdisinfectingpublicwatersupplies.Sufficientquantitiesofchlorinefromchlorinegasorhypochloritesareaddedtotreatedwatertokillpathogenicbacteria.Chlorinationisareliable,relativelyinexpensive,andeasydisinfectionmethodtouse.•为确保水中没有有害细菌，消毒是必须的。氯化处理是消毒公共水源最常用的方法。将氯气或次氯酸盐中足量的氯加入处理的水中杀死致病细菌。氯化处理是一种可靠的、相对廉价、容易使用的消毒方法。