英语演讲稿-水污染-英文.ppt
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英语演讲稿-水污染-英文.ppt
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waterenvironmentenvironmentWateristhesourceofallthingsItstheonlywater,butitstheliquidwonderthatmakesourworldpossible.Waterisabletodissolvemoresubstancesthananyotherliquid.Itstakesalotofwatertokeeplifegoing.123Somedatawateruse&pollutionwhatcanwedo71%ofearthssurfaceiscoveredwithwaterArethewatersourcesabundant?
lessthan3%OftotalwaterLowlayer0.3%offreshwaterChinawaterresourcerankfourthintheworld.Chinaisntrichinwaterresources.Obviously,theprospectofChinesewaterresourcesisntoptimistic.WaterIssuesinChinawithwaterresourcespercapitabeing2200m3orso,only1/4ofthatoftheworld.waterresourcespercapitaSouth:
population53%waterresource:
78%North:
population:
47%waterresource:
22%UnevendistributionofwaterresourcesnWaterisconsideredpollutedifasubstanceorconditionispresentthatrendersthewateruselessforaparticularpurposenThesourcesofwaterpollutionnDirectsourcesneffluentoutfallsfromfactories,refineries(精炼厂),wastetreatmentplants.nIndirectsourcesncontaminantsthatenterthewatersupplyfromsoils/groundwatersystemsandfromtheatmosphereviarainwater.AgriculturalWaterUseFourcommonirrigationmethods:
Surface/FloodRequiresextensivecanalsystemsSprayUsepumpsTrickleStrategicallyplacesopeningsSub-irrigationPipescanbeusedfordrainageaswellnExcessivefertilizerusemayleadtoeutrophication(水体富营养化)inmanyaquatichabitats.nAgriculturalrunofffromlarge,openexpansesismajorsourceofwaterpollution.AgriculturalWaterPollutionIndustrialWaterUseAccountsfornearly50%ofallwaterwithdrawalinU.S.,and23%worldwide.90%ofwaterusedbyindustryisforcooling,andisreturnedtothesource.Verylittleactuallyconsumed.Mostprocessesinvolveheatexchange.Waterusedtodissipateandtransportwaste.ToxicandoverloadwastesleadStreamandlakedegradation.IndustrialWaterPollutionAllkindsofindustrygeneratetradewaste(工业废水)IronandsteelindustryFoodindustryComplexorganicchemicalsindustryNuclearindustryPollutants:
organics,oil,metal,acidMayrequirespecialwastewatertreatment.DomesticWaterUse70%usedassolventtocarrywastes.30%usedforlawnandgarden.Verysmallfractionusedfordrinking.Naturalpurificationprocessescannotcopewithhighlyconcentratedurbanwastes.Mustbetreatedbeforerelease.DomesticwaterpollutionWastewaterfromBathing,dishes,toiletsNotoxicsubstance,abundantinnutrientswithnitrogen(N,氮)andphosphorus(P,磷)Eutrophication(水体富营养化)Trashorgarbage(e.g.paper,plastic,orfoodwaste)discardedbypeopleontheground,alongwithaccidentalorintentionaldumpingofrubbish,thatarewashedbyrainfallintostormdrainsandeventuallydischargedintosurfacewaters.Forgovernments1.Toestablishurbansewagetreatmentsystem(城市污水处理系统)2.TorestructureIndustrial3.Toencouragethedevelopmentofnewwatersources4.Tostrengthenlegislation,severepunishmentForplants1.Toreducewaterconsumption2.Tobuyequipmentofsewagetreatment3.Dontdischargesewageintowater4.TousewaterrecyclingsystemForindividuals1.DontusecleanerconcludeP2.Dontthrowthegarbageintotherivers3.Topromoteawarenessofpreservingwaterresources4.TotellthepersonsaroundyoutoprotectthewaterresourcesWorldWaterDay(WorldDayforWater)OnMarch22theUnitedNationsGeneralAssembly(联合国(联合国大会)大会)in1993aim:
toarousepublicsawarenessofeconomizingwatersources,andtoprotectitonethemeperyear2011:
waterforcitiesThankyou!
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- 英语演讲 水污染 英文