水资源供应与环境保护

CHAPTER5WATERRESOURCESANDWATERPOLLUTIONOutline1Water’sUniqueproperties2Freshwatersources3WaterResourcesAvailableinChina4Waterdemandcontrolandwatersaving5CleanerProductionImplementation6Treatmentofmunicipalwastewater7ControlofNon-pointsourcepollution8Developnon-traditionalwaterresources9StrategicMeasuresforSustainableManagementofWaterEnvironmentChallengesfacingChinaWaterShortageWaterPollution1Water’sUniquepropertiesStrongforcesofattraction(hydrogenbonds氢键)betweenmoleculesofwaterliquidwaterstoresmuchheatandchangestemperatureveryslowly（热稳定性强）lotsofheatisrequiredtoevaporatewaterwaterexistsasaliquidoverwiderangeoftemperatureithashighsurfacetension(表面张力)1Water’sUniquePropertiesAlsobecauseofuniquemolecularattractions:waterexpandsasitfreezes,becomeslessdense,andfloatswatercandissolveavarietyofcompoundsitcandissolveandcarrynutrients（营养物）andwastesaroundinlivingsystemsitcanremoveanddilute（稀释）watersolublewastes（易溶解的废物）ofcivilizationSupply,renewalanduseofwaterresources97%issaltwater-cannotbeusedtodrink,irrigateorforindustryMostofthe3%offreshwaterisfrozeninicecaps.0.592%isavailablefreshwater-constantlyrecycledinhydrologiccycle（水文循环）Wateravailabilityisfarfromuniform-duetovariationsinprecipitation（降水）;areasneedingthemostoftenhavetheleast.2FreshwatersourcesPrecipitation-surfacewaterflowsintostreams,etc.Awatershedisadrainagebasin-collectswaterwhichultimatelywillgotoaspecificplacePrecipitation-mayinfiltrate（渗透）groundfillingvoids（空隙）existingthere-calledgroundwaterHowdoweuseworld’sfreshwaterWeuse54%ofglobalsurfacerunoffGlobalwithdrawalrateisgrowingexponentially-butvariesworldwide:70%usedforirrigation-upto80%evaporates20%usedforindustry10%usedbyresidencesandcitiesDifferencesinwatersupplyandvaryingusesinU.S.andChina3WaterResourcesAvailableinChinaAnnualprecipitationinaverage648mmWaterresourcesavailable2800billionM3/aWaterResourceAvailablepercapita:2260m3percapita——1/4oftheworldaverageWaterResourceAvailableperhectareofland——3/4oftheworldaverage300citiesoutof640shortofwaterRichinsouth-east1000mmPoorinnorth-west≤200mmBeijing:600mmUnevenDistributionofwaterresourcesPrecipitationconcentratesin3-5monthsWaterQualityofRiversin2012Among409monitoringsectionof204rivers:ClassⅠ～Ⅲ68.9%ClassⅣ～Ⅴ20.9%WorsethanⅤ10.2%Waterqualityoflakesandreservoirin2012Among60monitoredlakesandreservoirs,25%appearsseriouseutrophication（富营养化）.GroundwaterProblemsWatertabledeclining（地下水位）Hardness(硬度)increasingNitrogenoxide（NO3）increasingSulphate（硫酸盐）、chlorid（氯化物）、iron（铁）、manganese（锰）etc，overproofOtherpollutantsPollutionaccidentsAlgaebloomingOilleakIllegaldischargeofheavymetals:Cr,Cd,Pb,Cu,etc.Otherpollutants.Havecauseddrinkingwatersafetyproblemsandharmfuleffectstohuman’shealth.EmergencyofwaterpollutioninSonghuaRiverandgreenalgaeoutbreakinTaihuLakeareremarkabletragedies.ChinaisfacingwatershortageseverelyUntilnow,humanbeingshouldrealizethatonlyhumansocietycoordinatinghisactionwiththewholewaterenvironmentofnature,humanbeingcanachievesustainabledevelopment.WhatShouldWeDoforWaterEnvironmentSustainabilityinChina?4WaterdemandcontrolandwatersavingindustrialrestructuringincreasingwaterefficiencyavoidwastesofwaterinproductionandconsumptionprocessesIrrigationLossesOnly40%ofwaterdivertedforirrigationreachescropsFloodirrigationdeliverstoomuchwaterLow-energyprecision（准确性）applicationsprinklersTrickleordripirrigationsystemsminimizeevaporationComputersystemsmonitorsoilmoistureAqueduct（沟、渠）WatersavingagricultureCropplantedshouldbecarefullyselectedbasedonavailablewaterresourcesAdvancedirrigationtechnologiesshouldbeappliedtoreducewaterconsumptionandwastageTheportionofagriculturewateruseintotalwaterconsumptionshouldbereducedWaterconsumptionforagricultureinBeijingdecreasedobviouslyinlatest20years,becausetheareasforricefieldhasbeendecreaseddramatically.ToadjustindustrialstructureforreducingwaterconsumptionToimplementcleanerproductionandincreaserecyclingrateofwaterforincreasingwaterutilizationrateWaterconsumptionforindustriesshouldnotbeincreaseorevenbereducedwhiletheindustrialproductionvalueisincreasing.WatersavingindustryWaterconsumptionpertonsteelinChina200025M3/tonsteel20104M3/tonsteelRaisingpublicawarenessonwatersavingApplywatersavingappliancesReduceandeliminatewaterleakageFormulateincentivepolicy（规划激励政策）andrationalpriceofwaterWatersavingsocietyExistingProblemsWaterefficiencyforagricultureislow:45％-50％,Watercirculatingrateinindustriesislow:50%-60%，Leakrateofurbanwatersupplysystemsishigh:30%-40%,Golfcoursesarewastinggreatamountofwater.5CleanerProductionImplementationItisthebestwaytocontrolindustrialpollutionfromthesources.LawonpromotionofcleanerproductioninChinahasbecomeeffectivein1Jan.2003.5CleanerProductionImplementationDemonstrationprojects（示范工程）oncleanerproductionhavebeencarriedoutin10citiesand5industrialsectors.Someecologicalindustrialparksplayimportantroleinresourceconservationandpollutioncontrol.CleanerproductiondemonstrationcityprograminChinaThegoalofthisproject:todevelopmechanismforpromotingcleanerproducti