英语演讲稿-水污染-英文PPT.ppt

water environment Wateristhesourceofallthings It stheonlywater butit stheliquidwonderthatmakesourworldpossible Waterisabletodissolvemoresubstancesthananyotherliquid It stakesalotofwatertokeeplifegoing Somedata wateruse pollution whatcanwedo 71 ofearth ssurfaceiscoveredwithwater Arethewatersourcesabundant lessthan3 Oftotalwater Lowlayer 0 3 offreshwater Chinawaterresourcerankfourthintheworld Chinaisn trichinwaterresources Obviously theprospectofChinesewaterresourcesisn toptimistic WaterIssuesinChina withwaterresourcespercapitabeing2200m3orso only1 4ofthatoftheworld waterresourcespercapita South population53 waterresource 78 North population 47 waterresource 22 Unevendistributionofwaterresources Waterisconsideredpollutedifasubstanceorconditionispresentthatrendersthewateruselessforaparticularpurpose ThesourcesofwaterpollutionDirectsourceseffluentoutfallsfromfactories refineries 精炼厂 wastetreatmentplants Indirectsourcescontaminantsthatenterthewatersupplyfromsoils groundwatersystemsandfromtheatmosphereviarainwater AgriculturalWaterUse Fourcommonirrigationmethods Surface FloodRequiresextensivecanalsystemsSprayUsepumpsTrickleStrategicallyplacesopeningsSub irrigationPipescanbeusedfordrainageaswell Excessivefertilizerusemayleadtoeutrophication 水体富营养化 inmanyaquatichabitats Agriculturalrunofffromlarge openexpansesismajorsourceofwaterpollution AgriculturalWaterPollution IndustrialWaterUse Accountsfornearly50 ofallwaterwithdrawalinU S and23 worldwide 90 ofwaterusedbyindustryisforcooling andisreturnedtothesource Verylittleactuallyconsumed Mostprocessesinvolveheatexchange Waterusedtodissipateandtransportwaste ToxicandoverloadwastesleadStreamandlakedegradation IndustrialWaterPollution Allkindsofindustrygeneratetradewaste 工业废水 IronandsteelindustryFoodindustryComplexorganicchemicalsindustryNuclearindustryPollutants organics oil metal acidMayrequirespecialwastewatertreatment DomesticWaterUse 70 usedassolventtocarrywastes 30 usedforlawnandgarden Verysmallfractionusedfordrinking Naturalpurificationprocessescannotcopewithhighlyconcentratedurbanwastes Mustbetreatedbeforerelease Domesticwaterpollution WastewaterfromBathing dishes toiletsNotoxicsubstance abundantinnutrientswithnitrogen N 氮 andphosphorus P 磷 Eutrophication 水体富营养化 Trashorgarbage e g paper plastic orfoodwaste discardedbypeopleontheground alongwithaccidentalorintentionaldumpingofrubbish thatarewashedbyrainfallintostormdrainsandeventuallydischargedintosurfacewaters Forgovernments 1 Toestablishurbansewagetreatmentsystem 城市污水处理系统 2 TorestructureIndustrial3 Toencouragethedevelopmentofnewwatersources4 Tostrengthenlegislation severepunishment Forplants 1 Toreducewaterconsumption2 Tobuyequipmentofsewagetreatment3 Don tdischargesewageintowater4 Tousewaterrecyclingsystem Forindividuals 1 Don tusecleanerconcludeP2 Don tthrowthegarbageintotherivers3 Topromoteawarenessofpreservingwaterresources4 Totellthepersonsaroundyoutoprotectthewaterresources WorldWaterDay WorldDayforWater OnMarch22theUnitedNationsGeneralAssembly 联合国大会 in1993aim toarousepublic sawarenessofeconomizingwatersources andtoprotectitonethemeperyear2011 waterforcities Thankyou