Solid-Waste-Management-and-Disposal固体废物管理和处置.ppt

SolidWasteManagementandDisposal,Outline,WasteDisposalMethodsLandfills,Incineration,CompostingSourceReduction源头削减RecyclingProblemsandConcernsRegulatinghazardousmaterialsHazardousvs.ToxicSettingRegulationsAssociatedHealthRisksEPAsManagementStrategy,MunicipalSolidWaste,Inmodernsociety,manyproductsarediscardedwhentheyarebrokenorwornout,whileothersonlyhaveatemporaryuse.Thosethathaveonlytemporaryusesmakeupthemajorityofsolidwaste.,Lackofdumping堆放spacehasbecomeaproblemformanylargemetropolitan大都市areas.Why?PopulationincreaseConveniencelifestyleCommunitiesareincreasinglyconcernedaboutwastedisposalcosts,andgroundwater(landfill)andairqualityhazards(burning).,DisposableDecades,Inthemid1950sadisposable用后即弃lifestylewasmarketedasthewaveofthefuture,andasawaytoreducehouseholdduties.ConsumerismbeganinearnestfollowingWWII.Conveniencewassoldtoprosperouspost-warconsumers.“Convenience”wasquicklychangedtonecessity.,NatureoftheProblem,Garbage=MunicipalSolidWasteUSproduces220millionmetrictonsofmunicipalwasteperyear,2kg/p.d.USvolumehasdoubledsince1960.,MunicipalSolidWasteGenerationRates,CHNproduces108millionmetrictonsin1996,0.3kg/p.d,0.8-2.0kg/p.dincities.CHNvolumeincreased8-10%peryearrecently,willdoublein7years.MDCshaveahigherstandardofliving,andthusproducemorewaste.,WasteGenerationandLifestyle,WasteGenerationandLifestyle,WasteDisposalMethods,TraditionalMethods(dumpingandburning)arenolongeraccepted.Essentially,fourtechniquesareused:LandfillsIncinerationCompostingRecyclingFig.18.7,Compositionoftrash(U.S.CHN),MethodsofWasteDisposal,LandfillsLandfillinghastraditionallybeentheprimarymethodofwastedisposal-cheapandconvenient.Traditional-AsimpleholeinthegroundtodumpgarbageGroundwatercontamination,Modernlandfillshavecompleximpermeablebottomlayerstotrapcontaminants,anddailydepositsarecoveredbylayerofdirt.Methanegasandgroundwaterdetectionsystems.Gasrecoveryandleachatecollectionandtreatmentsystems.(biochemicalprocessorreverseosmosismembrane)Modernlandfillscost$1million/ha.,Modernlandfills,Currently,almost57%ofUSmunicipalsolidwasteisdepositedinlandfills.70%ofCHNwasteisland-filledinCHNstyleavalley,i.e.HangzhouTianziling,Newlandfillsareoftenresistedduetopublicconcernsovergroundwatercontamination,odors,andtrucktraffic.Localopposition,not-in-my-backyardUnwillingofpoliticians,not-in-my-election-yearLandscarcities,alternativeway?,外国城市生活垃圾各种处理方式所占的比例（%）,Incineration,Priorto1940,incinerationwascommoninNAandwesternEurope.Manyincineratorswereeliminatedbecauseofaestheticconcerns.i.e.foulodors,grittysmoke.Currently,about16%ofUSmunicipalsolidwasteisincinerated.CHN,onlysomelargecities.Derivedheatoftenusedforelectricalgeneration.Fig.18.11,incinerator,Incinerationandelectricalgeneration,Incineratorsdrasticallyreducetheamountofmunicipalsolidwaste-upto90%byvolumeand75%byweight.Evenwithmodernpollutioncontrols,smallamountsofpollutantsarestillreleasedintoenv.Air,acidgases,dioxinsandfuransAsh(flyash+bottomash),concentratedmetals,Costandsittingofnewincineratorsmajorproblemsfacingcommunities.incinerationbecomeeffectivewhentransportationtoinstantlandfills.,CompostingYardwasteFoodwasteManureSoiladditiveRemovetoxinawaybeforecomposting,SourceReduction,Mostfundamentalmethodofreducingwasteistopreventitfrombeingproduced.HeavypackagingmaterialstolightonesSince2litersoftdrinkbottlewasintroducedin1977,weighthasbeenreducedby35%Since1965,aluminumcanshavebeenreducedinweightby35%.Makingproductsinconcentratedform,dependsonconsumer,Recycling,Currently23%ofNAwasteisrecycled.RecyclinginitiativeshavegrownrapidlyinNAduringthepastseveralyears.Recyclingrate,Fig.18.14,RecyclingBenefits,ResourceConservationPollutionReductionExample:OneSundayeditionofN.Y.timesconsumes62,000trees.Only20%ofNApaperisrecycled.Example:Crushedglassreducestheenergyrequiredtomanufacturenewglassby50%,RecyclingConcerns,Plasticsarerecyclable,buttechnologydiffersfromplastictoplastic.P.431,close-up.Lowestrecyclingrate.Industryisresearchingnewtechnologies.Economicsareofconcern.Unlessdemandforproductskeepspacewithgrowingsupply,recyclingprogramswillfaceanuncertainfuture.,Long-termsuccessofrecyclingprogramsisalsotiedtoothereconomicincentivessuchastaxationandthedevelopmentofanddemandforproductsmanufacturedfromrecycledmaterials.CurrentlyintheUS,itisoftenstillcheapertousevirginmaterialthantransportrecycledmaterials.,REGULATINGHAZARDOUSMATERIALS,Hazardous-EPAdefineshazardousmaterialsashavingoneormoreofthefollowingcharacteristics:Ignitability(Firehazard)Corrosiveness(Corrodesmaterial)Reactivity(Unstable)Toxicity(Mayreleasetoxins),HazardousversusToxicTermsarenotInterchangeable,Toxic-Commonlyreferstoanarrowgroupofsubstancesthatcausehumaninjuryordeath.Hazardous-Broaderterm-referstoalldangerousmaterialsthatcreateahumanhealth,orenvironmentalproblem.,DefiningHazardousWaste,VariesfromonecountrytoanotherU.S.ResourceConservationandRecoveryAct(RCRA)1976-,RCRAconsiderswastestoxic/hazardousifthey:,Causeorsignificantlycontributetoanincreaseinmortalityoranincreaseinseriousirreversible,orincapacitatingreversible,illness;orposeasubstantialpresentorpotentialhazardtohumanhealthortheenvironmentwhenproperlytreated,stored,transported,disposedof,orotherwisemanaged.,IssuesInvolvedinSettingRegulations,IdentificationofHazardous&ToxicMaterialsListoftenlimitedtocurrentoffendersSettingExposureLimitsNearlyallsubstancesaretoxicinsufficientquantitiesSpecies-SpecificThresholds,Acutevs.ChronicToxicityEffectsofmassivedoses(acute)andsmalldosesovertime(chronic)differgreatly.ChronicmuchhardertodetectSynergismMosttoxicitystudiesdoneonasinglecompound.,PersistenceandNon-PersistencePersistenttoxinsremainintheenv.,essentiallyunchanged,forlongperiods-build-upleadstochronicproblems.Non-Persistenttoxinsdonotremainforalongperiod,andareoftenbiodegradable,andusuallyresponsibleforacuteproblems.,HealthRisksAssociatedwithHazardousWastes,Eachyear,roughly1,000newchemicalsareproducedanddistributed.Mainproblemischemicalproductsandby-productsofindustryareoftenhandledanddisposedofimproperly.,Hazardous