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Bailie,R.C.;Everett,J.W.;et.al.“SolidWaste”EnvironmentalEngineer'sHandbookEd.DavidH.F.Liu&BelaG.LiptakBocaRaton:CRCPressLLC,1999c1999byCRCPressLLC SolidWasteR.C.Bailie|J.W.Everett|BélaG.Lipták|DavidH.F.Liu|F.MackRugg|MichaelS.SwitzenbaumSourceandEffect10.4CHARACTERIZATIONMETHODS10.1PurposesofSolidWasteDEFINITIONCharacterizationWasteTypesIncludedBasicCharacterizationMethodsWasteTypesNotIncludedEstimationofWasteQuantitySamplingMSWtoEstimateComposition10.2SelectingSamplesSOURCES,QUANTITIES,ANDEFFECTSCollectingSamplesSourcesNumberofSamplesRequiredtoEstimateQuantitiesCompositionEffectsSortingandWeighingSamplesofMSWSortingAreasSortingContainersCharacterizationContainerLabelingSortingProcess10.3WeighingSamplesPHYSICALANDCHEMICALCHARACTER-DumpingSamplesISTICSProcessingtheResultsofSortingFluctuationsinSolidWasteQuantitiesVisualCharacterizationofBulkyComponentCompositionofMSWWasteComponentCompositionofBulkySamplingMSWforLaboratoryWasteAnalysisDensityMixedSampleversusComponentSampleParticleSize,Abrasiveness,andOtherTestingPhysicalCharacteristicsCombustionCharacteristicsLaboratoryProceduresProximateCompositionCollectingMaterialforLaboratoryUltimateCompositionSubsamplesHeatValueReviewandUseofLaboratoryResultsBioavailabilityEstimatingCombustionCharacteristicsBasedToxicSubstancesinSolidWasteonLimitedLaboratoryTesting©1999CRCPressLLC 10.5TreatmentandDisposalIMPLICATIONSFORSOLIDWASTEMANAGEMENT10.9ImplicationsforWasteReductionWASTE-TO-ENERGYINCINERATORSImplicationsforWasteProcessingMass-BurnandRDFIncineratorsImplicationsforRecoveryofUsefulPlantDesignMaterialsConceptofState-of-the-ArtImplicationsforIncinerationandEnergyDesignBasisRecoveryProcessDesignImplicationsforLandfillingWasteReceivingandStorageFeedingSystemsTheFurnaceResourceConservationandHeatRecoveryIncinerators(HRIs)ResidueHandlingRecoveryAirPollutionControl(APC)Instrumentation10.6REDUCTION,SEPARATION,ANDRECYCLING10.10MunicipalWasteReductionSEWAGESLUDGEINCINERATIONProductReuseSludgeIncinerationEconomicsIncreasedProductDurabilityIncinerationProcessesReducedMaterialUsageperProductFlash-DryerIncinerationUnitMultiple-HearthIncinerationDecreasedConsumptionFluidized-BedIncinerationReducingWasteToxicityFluidized-BedIncinerationwithHeatSeparationattheSourceRecovery“BottleBills”Recycling10.11PlasticONSITEINCINERATORSToxicSubstancesLocationPaperSelectionGlassChargingMetalsAccessoriesRubberControlsIncineratorAshDomesticandMultiple-DwellingIncineratorsMiscellaneousOnsiteIncinerators10.7MATERIALRECOVERY10.12RoleofMRFsandMRF/TFsPYROLYSISOFSOLIDWASTEMRFsforSource-SeparatedWastePyrolysisPrinciplesPaperandCardboardEnergyRelationshipsAluminumandTinCansEffectofThermalFluxPlasticandGlassSolidSizeMSWProcessingTypesofEquipmentMRFPlantforPartiallySeparatedExperimentalDataMSWStatusofPyrolysisMaterialRecoveryPlant10.13SANITARYLANDFILLS10.8LandfillRegulationsREFUSE-DERIVEDFUEL(RDF)LocationRestrictionsRDFPreparationPlantEmissions,Leachate,andMonitor-GradesofRDFingModelingRDFPerformanceSitingNewLandfills©1999CRCPressLLC EstimatingRequiredSiteAreaSitePreparationandLandfillExclusiveandNonexclusiveSitingOperationCriteriaClosure,Postclosure,andEndUseDesignSpecialLandfillsLandfillTypesConclusionLeachateControlFinalCoverandSurfaceWater10.14ControlsCOMPOSTINGOFMSWLinersAerobicCompostinginMSWCollectionandLeakDetectionManagementSystemsSeparatedandCommingledWasteLeachateDisposalSystemsCocompostingRetrievedOrganicswithLeachateMonitoringSludgeGasControlMunicipalCompostingStrategies©1999CRCPressLLC SourceandEffect10.1DEFINITIONForpracticalpurposes,thetermwasteincludesanymate-Bulkywasteconsistsoflargeritemsofsolidwaste,suchrialthatentersthewastemanagementsystem.Inthischap-asmattressesandappliances,aswellassmalleritemsgen-ter,thetermwastemanagementsystemincludesorganizederatedinlargequantityinashorttime,suchasroofingprogramsandcentralfacilitiesestablishednotonlyforfi-shingles.Ingeneral,regulartrashcollectioncrewsdonotnaldisposalofwastebutalsoforrecycling,reuse,com-pickupbulkywastebecauseofitssizeorweight.posting,andincineration.Materialsenterawasteman-BulkywasteisfrequentlyreferredtoasC&D(con-agementsystemwhennoonewhohastheopportunitytostructionanddemolition)waste.Themajorityofbulkyretainthemwishestodoso.wastegeneratedinagivenareaislikelytobeC&Dwaste.Generally,thetermsolidwastereferstoallwastema-Inareaswhereregulartrashcollectioncrewstakeanythingterialsexcepthazardouswaste,liquidwaste,andatmos-putout,themajorityofbulkywastearrivingseparatelyatphericemissions.CIIwastereferstowastesgeneratedbydisposalfacilitiesisC&Dwaste.Inareaswheretheregu-commercial,industrial,andinstitutionalsources.Althoughlarcollectioncrewsarelessaccommodating,however,sub-mostsolidwasteregulationsincludehazardouswastestantialquantitiesofothertypesofbulkywaste,suchaswithintheirdefinitionofsolidwaste,solidwastehascomefurnitureandappliances,arriveatdisposalfacilitiesinsep-tomeannonhazardoussolidwasteandgenerallyexcludesarateloads.hazardouswaste.Thissectiondescribesthetypesofwastethatarede-WasteTypesNotIncludedtailedinthischapter.Inabroadsense,themajorityofnonhazardoussolidwasteconsistsofindustrialprocessingwastessuchasmineandmilltailings,agriculturalandfoodprocessingwaste,coalWasteTypesIncludedash,cementkilndust,andsludges.ThewastemanagementThischapterfocusesontwomajortypesofsolidwaste:technologiesdescribedinthischaptercanbeusedtoman-municipalsolidwaste(MSW)andbulkywaste.MSWagethesewastes;however,thischapterfocusesontheman-comprisessmallandmoderatelysizedsolidwasteitemsagementofMSWandthemorecommontypesofbulkyfromhomes,businesses,andinstitutions.Forthemostwasteinmostlocalsolidwastestreams.part,thiswasteispickedupbygeneralcollectiontrucks,typicallycompactortrucks,onregularroutes.—F.MackRugg©1999CRCPressLLC 10.2SOURCES,QUANTITIES,ANDEFFECTSThissectionidentifiesthesourcesofsolidwaste,providesofabuilding,ortheresurfacingofaroad.Therefore,thegeneralinformationonthequantitiesofsolidwastegen-compositionofbulkywasteismorevariablethanthecom-eratedanddisposedofintheUnitedStates,andidentifiespositionofMSW.thepotentialeffectsofsolidwasteondailylifeandtheen-Intermsofgenerationsites,theprincipalsourcesofvironment.MSWarehomes,businesses,andinstitutions.Bulkywasteisalsogeneratedatfunctioninghomes,businesses,andin-stitutions;butthemajorityofbulkywasteisgeneratedatSourcesconstructionanddemolitionsites.Ateachtypeofgener-ationsite,MSWandbulkywastearegeneratedunderfourTheprimarysourceofsolidwasteistheproductionofbasiccircumstances:commoditiesandbyproductsfromsolidmaterials.Everythingthatisproducediseventuallydiscarded.Asec-Packagingisremovedoremptiedandthendiscarded.Thisondarysourceofsolidwasteisthenaturalcycleofplantwastetypicallyaccountsforapproximately35to40%growthanddecay,whichisresponsiblefortheportionofofMSWpriortorecycling.Packagingisgenerallylessthewastestreamreferredtoasyardwasteorvegetativeabundantinbulkywaste.waste.Theunusedportionofaproductisdiscarded.InMSW,Theamountaproductcontributestothewastestreamthiswasteaccountsforallfoodwaste,asubstantialpor-isproportionaltotwoprincipalfactors:thenumberoftionofwoodwaste,andsmallerportionsofotherwasteitemsproducedandthesizeofeachitem.Thenumberofcategories.Inbulkywaste,thiswasteaccountsfortheitemsproduced,inturn,isproportionaltotheusefullifemajorityofconstructionwaste(scrapsoflumber,gyp-oftheproductandthenumberofitemsinuseatanyonesumboard,roofingmaterials,masonry,andothercon-time.NewspapersarethelargestcontributortoMSWbe-structionmaterials).causetheyarelargerthanmostotheritemsinMSW,theyAproductisdiscarded,orastructuredemolished,afterareusedinlargenumbers,andtheyhaveausefullifeofuse.Thiswastetypicallyaccountsfor30to35%ofonlyoneday.Incontrast,pocketknivesmakeupanegli-MSWandthemajorityofbulkywaste.gibleportionofMSWbecauserelativelyfewpeopleuseUnwantedplantmaterialisdiscarded.Thiswasteisthethem,theyaresmall,andtheyaretypicallyusedforyearsmostvariablesourceofMSWandisalsoahighlyvari-beforebeingdiscarded.ablesourceofbulkywaste.Yardwastessuchasleaves,MSWischaracterizedbyproductsthatarerelativelygrassclippings,andshrubandgardentrimmingscom-small,areproducedinlargenumbers,andhaveshortuse-monlyaccountforaslittleas5%orasmuchas20%fullives.BulkywasteisdominatedbyproductsthatareoftheMSWgeneratedinacounty-sizedareaonanan-largebutareproducedinrelativelysmallnumbersandnualbasis.Plantmaterialcanbealargecomponentofhaverelativelylongusefullives.Therefore,agivenmassbulkywastewheretreesorwoodyshrubsareabundant,ofMSWrepresentsmorediscreetactsofdiscardthantheparticularlywhenlotsareclearedfornewconstruction.samemassofbulkywaste.Forthisreason,moredataarePackagingtendstobeconcentratedinMSWbecauserequiredtocharacterizebulkywastetowithinagivenlevelmanypackagesdestinedfordiscardasMSWcontainprod-ofstatisticalconfidencethanarerequiredtocharacterizeuctsofwhichthemajorityisdiscardedinwastewaterorMSW.enterstheatmosphereasgasinsteadofbeingdiscardedasMostMSWisgeneratedbytheroutineactivitiesofMSW.Suchproductsincludefoodandbeverages,clean-everydayliferatherthanbyspecialorunusualactivitiesoringproducts,hair-andskin-careproducts,andpaintsandevents.Ontheotherhand,activitiesthatdeviatefromrou-otherfinishes.tine,suchastryingdifferentfoodoranewrecreationalactivity,generatewasteatahigherratethanroutineac-tivities.Routinelypurchaseditemstendtobeusedfully,Quantitieswhileunusualitemstendtobediscardedwithoutuseorafteronlypartialuse.ThemostimportantparameterinsolidwastemanagementIncontrasttoMSW,mostbulkywasteisgeneratedbyisthequantitytobemanaged.Thequantitydeterminesrelativelyinfrequentevents,suchasthediscardofasofathesizeandnumberofthefacilitiesandequipmentre-orrefrigerator,thereplacementofaroof,thedemolitionquiredtomanagethewaste.Alsoimportant,thefeecol-©1999CRCPressLLC lectedforeachunitquantityofwastedeliveredtothefa-FranklinAssociates’s(1992)estimateofMSWgener-cility(thetippingfee)isbasedontheprojectedcostofop-atedintheUnitedStatesin1990,previouslynoted,equateseratingafacilitydividedbythequantityofwastethefa-to4.29lbperpersonperday.Thisestimateisprobablycilityreceives.lowforthefollowingreasons:ThequantityofsolidwastecanbeexpressedinunitsWastematerialisnotincludedifFranklinAssociatescan-ofvolume(typicallycubicyardsorcubicmeters)orinunitsnotdocumenttheoriginalproductionofthematerial.ofweight(typicallyshort,long,ormetrictons).InthisFranklin’smaterialflowsmethodologygenerallydoesnotchapter,thewordtonreferstoashortton(2000lb).accountformoistureabsorbedbymaterialsaftertheyAlthoughinformationaboutbothvolumeandweightarearemanufactured(see“CombustionCharacteristics”inimportant,usingweightasthemasterparameterisgener-Section10.3).allypreferableinrecordkeepingandcalculations.TheadvantageofmeasuringquantityintermsofweightTable10.2.1showswastequantitiesreportedforvari-ratherthanvolumeisthatweightisfairlyconstantforaouscountiesandcitiesintheUnitedStates.Allquantitiesgivensetofdiscardedobjects,whereasvolumeishighlyaregiveninpcd.Reportsfromthelocationslistedinthevariable.WastesetoutonthecurbonagivendayinatableindicateanaveragegenerationrateforMSWof5.4givenneighborhoodoccupiesdifferentvolumesonthepcd,approximately25%higherthantheFranklincurb,inthecollectiontruck,onthetippingfloorofatrans-Associatesestimate.Roughly60%ofthiswasteisgener-ferstationorcompostingfacility,inthestoragepitofaatedinresidences(residentialwaste)whiletheremainingcombustionfacility,orinalandfill.Inaddition,thesame40%isgeneratedincommercial,industrial,andinstitu-wastecanoccupydifferentvolumesindifferenttrucksortionalestablishments(CIIwaste).ThepercentageofCIIlandfills.Similarly,twoidenticaldemolishedhousesoc-wasteisusuallylowerinsuburbanareaswithoutamajorcupydifferentvolumesifoneisrepeatedlyrunoverwithurbancenterandhigherinurbanregionalcenters.abulldozerandtheotherisnot.Astheseexamplesillus-Table10.2.1alsoshowsgenerationratesforsolidwastetrate,thephrases“acubicyardofMSW”and“acubicotherthanMSW.Thequantityofotherwaste,mostofyardofbulkywaste”havelittlemeaningbythemselves;whichisbulkywaste,isroughlyhalfthequantityofMSW.thephrases“atonofMSW”and“atonofbulkywaste”Theproportionofbulkyandotherwastevaries,however,aremoremeaningful.andisheavilyinfluencedbythedegreetowhichrecycledFranklinAssociates,Ltd.,regularlyestimatesthequan-bulkymaterialsarecountedaswaste.ThequantitiesoftityofMSWgeneratedanddisposedofintheUnitedStatesbulkywasteshownforAtlanticandCapeMaycounties,undercontracttotheU.S.EnvironmentalProtectionNewJersey,includelargeamountsofrecycledconcrete,Agency(EPA).FranklinAssociatesderivesitsestimatesasphalt,andscrapmetal.Seealso“ComponentCompo-fromindustrialproductiondatausingthematerialflowssitionofBulkyWaste”inSection10.3.methodology,basedonthegeneralassumptionthatwhatFranklinAssociates(1992)projectsthatthetotalquan-isproducediseventuallydiscarded(see“EstimationoftityofMSWgeneratedintheUnitedStateswillincreaseWasteQuantity”inSection10.4).FranklinAssociateses-by13.5%between1990and2000whilethepopulationtimatesthat195.7milliontonsofMSWweregeneratedwillincreasebyonly7.3%.Onapercapitabasis,there-intheUnitedStatesin1990.Ofthistotal,anestimatedfore,MSWgenerationisprojectedtogrow0.56%per33.4milliontons(17.1%)wererecoveredthroughrecy-year.Nocomparableprojectionshavebeendevelopedforclingandcomposting,leaving162.3milliontonsfordis-bulkywaste.Table10.2.2showsthepotentialeffectofthisposal(FranklinAssociates,Ltd.1992).growthrateonMSWgenerationratesandquantities.Thequantityofsolidwasteisoftenexpressedinpoundspercapitaperday(pcd)sothatwastestreamsindifferentareascanbecompared.Thisquantityistypicallycalcu-Effectslatedwiththefollowingequation:MSWhasthefollowingpotentialnegativeeffects:pcd52000T/365P10.2(1)where:•Promotionofmicroorganismsthatcausediseases•Attractionandsupportofdiseasevectors(rodentspcd5poundspercapitaperdayandinsectsthatcarryandtransmitdisease-caus-T5numberoftonsofwastegeneratedinayearingmicroorganisms)P5populationoftheareainwhichthewasteisgen-erated•Generationofnoxiousodors•Degradationoftheestheticqualityoftheenvi-Unlessotherwisespecified,thetonnageTincludesbothronmentresidentialandcommercialwaste.Withmodificationthe•Occupationofspacethatcouldbeusedforotherequationcanalsocalculatepoundsperemployeeperday,purposesresidentialwasteperpersonperday,andsoon.•Generalpollutionoftheenvironment©1999CRCPressLLC TABLE10.2.1SOLIDWASTEGENERATIONRATESINTHEUNITEDSTATESCommercial/ResidentialIndustrialOtherTotalFractionofFractionofTotalBulkySolidSolidMSWMSWMSWWasteWasteWasteLocationYear(%)(%)(pcd)(pcd)(pcd)a(pcd)AtlanticCounty,NJ1991——6.05.90.312.2BexarCounty,TX1990—————6.5CapeMayCounty,NJ1990——6.66.00.613.2Delaware(state)1990—————7.1FairfaxCounty,VA199155454.81.30.06.1MarionCounty,FL1989——5.4———MiddlesexCounty,NJ1988——4.42.11.68.2MinnesotaMetroArea1991——6.52.60.09.1MonmouthCounty,NJ198775254.82.70.07.5MonroeCounty,NY1990——5.7———RhodeIsland(state)198552484.9———SanDiego,CA1985—————8.0SarasotaCounty,FL1989—————9.2Seattle,WA198737637.6———SomersetCounty,NJ1989——4.21.50.66.3WarrenCounty,NJ1989——3.20.40.94.5Wichita,KA199061396.61.10.07.7bAverage56445.42.60.58.1Minimum37253.20.40.04.5Maximum75637.66.01.613.2USA(FranklinAssociates)199062384.3———Sources:Datafromreferenceslistedattheendofthissection.Note:pcd5poundspercapitaperdayaMostwasteinthiscategoryfallswithinthedefinitionofeitherMSWorbulkywaste.Specificcharacteristicsvaryfromplacetoplace.bBecausedifferentinformationisavailablefromdifferentlocations,theoverallaverageisnotthesumoftheaveragesfortheindividualwastetypes.BulkywastealsohasthepotentialtodegradeestheticBulkywastehasthesamepotentialusesexceptforcom-values,occupyvaluablespace,andpollutetheenviron-postingfeedstock.ment.Inaddition,bulkywastemayposeafirehazard.ThefundamentalchallengeofsolidwastemanagementMSWisapotentialsourceofthefollowingusefulma-istominimizethepotentialnegativeeffectswhilemaxi-terials:mizingtherecoveryofusefulmaterialsfromthewasteatareasonablecost.•RawmaterialstoproducemanufacturedgoodsConformancewithsimple,standardproceduresforthe•FeedstockforcompostingandmulchingprocessesstorageandhandlingofMSWlargelypreventsthepro-•Fuelmotionofdisease-causingmicroorganismsandtheattrac-TABLE10.2.2PROJECTEDGENERATIONOFMSWINTHEUNITEDSTATESINTHEYEAR2000AverageMSWQuantityPerCapitaAnnualPerCapitaMSWQuantityProjectedbyGenerationGrowthofGenerationBasedonFranklinBasedonPerCapitaBasedonAverageinPopulationAssociatesFranklinGenerationAverageinTable10.2.1(in(millionsAssociatesRepresentedTable10.2.1(millionsYearmillions)oftons)(lb/day)(%)(lb/day)oftons)1990249.9195.74.3—5.4247.62000268.3222.14.50.565.7281.0Source:DatafromFranklinAssociates,Ltd.,1992,CharacterizationofmunicipalsolidwasteintheUnitedStates:1992Update(EPA/530-R-92-019,NTISPB92-207-166,U.S.EPA).Note:DerivedfromTable10.2.1.©1999CRCPressLLC tionandsupportofdiseasevectors.Preventingthere-ofsolidwastecompostmustberegulatedsothatthesoilmainingpotentialnegativeeffectsofsolidwasteremainsisnotcontaminated(seeSection10.14).asubstantialchallenge.WhileavoidingthepotentialnegativeeffectsofsolidSolidwastecandegradetheestheticqualityoftheen-waste,asolidwastemanagementprogramshouldalsoseekvironmentintwofundamentalways.First,wastemateri-toderivebenefitsfromthewaste.Methodsforderivingalsthatarenotproperlyisolatedfromtheenvironmentbenefitsfromsolidwasteincluderecycling(Section10.7),(e.g.,streetlitteranddebrisonavacantlot)aregenerallycomposting(Section10.14),directcombustionwithen-unsightly.Second,solidwastemanagementfacilitiesareergyrecovery(Section10.9),processingwastetoproduceoftenconsideredunattractive,especiallywhentheystandfuel(Sections10.8and10.12),andrecoveryoflandfillgasoutfromsurroundingphysicalfeatures.Thischaracteris-foruseasafuel(Section10.13).ticisparticularlytrueoflandfillsonflatterrainandcom-bustionfacilitiesinnonindustrialareas.—F.MackRuggSolidwastelandfillsoccupysubstantialquantitiesofspace.Wastereduction,recycling,composting,andcom-Referencesbustionallreducethevolumeoflandfillspacerequired(seeSections10.6to10.14).CalRecoverySystems,Inc.1990.WastecharacterizationforSanLandonwhichsolidwastehasbeendepositedisdiffi-Antonio,Texas.Richmond,Calif.(June).CampDresser&McKeeInc.1990a.MarionCounty(FL)solidwasteculttouseforotherpurposes.Landfillsthatreceiveun-compositionandrecyclingprogramevaluation.Tampa,Fla.(April).processedMSWtypicallyremainspongyandcontinueto———.1990b.SarasotaCountywastestreamcompositionstudy.Draftsettlefordecades.Suchlandfillsgeneratemethane,acom-report(March).bustiblegas,andothergasesfortwentyyearsormoreaf-———.1991a.CapeMayCountymulti-seasonalsolidwastecomposi-tertheyceasereceivingwaste.Whetherthewasteinaland-tionstudy.Edison,N.J.(August).———.1991b.CityofWichitawastestreamanalysis.Wichita,Kans.fillisprocessedorunprocessed,thelandfillgenerally(August).cannotbereforested.Treerootsdamagetheimpermeable———.1992.AtlanticCounty(NJ)solidwastecharacterizationpro-capappliedtoaclosedlandfilltoreducetheproductiongram.Edison,N.J.(May).ofleachate.Cosulich,WilliamF.,Associates,P.C.1988.SolidwastemanagementSolidwastegeneratesodorsasmicroorganismsmetab-plan,CountyofMonroe,NewYork:Solidwastequantificationandcharacterization.Woodbury,N.Y.(July).olizeorganicmatterinthewaste,causingtheorganicmat-DelawareSolidWasteAuthority.1992.Solidwastemanagementplan.tertodecompose.Themostacuteodorproblemsgener-(17December).allyoccurwhenwastedecomposesrapidly,consumingFranklinAssociates,Ltd.1992.Characterizationofmunicipalsolidwasteavailableoxygenandinducinganaerobic(oxygendefi-intheUnitedStates:1992update.U.S.EPA,EPA/530-R-92-019,cient)conditions.BulkywastegenerallydoesnotcauseNTISno.PB92-207166(July).HDREngineering,Inc.1989.Reportonsolidwastequantities,compo-odorproblemsbecauseittypicallycontainslittlematerialsitionandcharacteristicsforMonmouthCounty(NJ)wasterecoverythatdecomposesrapidly.MSW,ontheotherhand,typi-system.WhitePlains,N.Y.(March).callycausesobjectionableodorsevenwhencoveredwithKillamAssociates.1989;1991update.MiddlesexCounty(NJ)soliddirtinalandfill(seeSection10.13).wasteweighing,source,andcompositionstudy.Millburn,N.J.Combustionfacilitiespreventodorproblemsbyincin-(February).———.1990.SomersetCounty(NJ)solidwastegenerationandcom-eratingtheodorouscompoundsandthemicroorganismspositionstudy.Millburn,N.J.(May).IncludesdataforWarrenandorganicmatterfromwhichtheodorouscompoundsCounty,N.J.arederived(seeSection10.9).Compostingpreservesor-MinnesotaPollutionControlAgencyandMetropolitanCouncil.1993.ganicmatterwhilereducingitspotentialtogenerateodors.Minnesotasolidwastecompositionstudy,1991–1992partII.SaintHowever,thecompostingprocessrequirescarefulengi-Paul,Minn.(April).RhodeIslandSolidWasteManagementCorporation.1987.Statewideneeringtominimizeodorgenerationduringcompostingresourcerecoverysystemdevelopmentplan.Providence,R.I.(June).(seeSection10.14).SanDiego,Cityof,WasteManagementDepartment.1988.RequestforInadditiontoodors,solidwastecancauseotherformsproposal:Comprehensivesolidwastemanagementsystem.(4ofpollution.LandfillleachatecontainstoxicsubstancesNovember).thatmustbepreventedfromcontaminatinggroundwaterSCSEngineers.1991.Wastecharacterizationstudy—solidwasteman-agementplan,FairfaxCounty,Virginia.Reston,Va.(October).andsurfacewater(seeSection10.13).Toxicandcorro-SeattleEngineeringDepartment,SolidWasteUtility.1988.Wastere-siveproductsofsolidwastecombustionmustbepreventedduction,recyclinganddisposalalternatives:VolumeII—Recyclingfromenteringtheatmosphere(seeSection10.9).Theusepotentialassessmentandwastestreamforecast.Seattle(May).©1999CRCPressLLC Characterization10.3PHYSICALANDCHEMICALCHARACTERISTICSThissectionaddressesthecharacteristicsofsolidwastein-200%cludingfluctuationsinquantity;composition,density,andjotherphysicalcharacteristics;combustioncharacteristics;180%jbioavailability;andthepresenceoftoxicsubstances.160%140%FluctuationsinSolidWastejQuantities120%jrrrjrrWeaknessintheeconomygenerallyreducesthequantity100%rrrofsolidwastegenerated.ThisreductionisparticularlytruerrrrjjrforcommercialandindustrialMSWandconstructionand80%demolitiondebris.DataquantifyingtheeffectofeconomicPercentageofAveragejjjjdownturnsonsolidwastequantityarenotreadilyavail-60%jjable.40%Thegenerationofsolidwasteisusuallygreaterinwarmweatherthanincoldweather.Figure10.3.1showstwo20%month-to-monthpatternsofMSWgeneration.Thelessvariablepatternisacompositeofdatafromeightloca-0%tionswithcoldormoderatelycoldwinters(CampDresserJanFebMarAprMayJunJulAugSepOctNovDecJanMonthofYear&McKeeInc.1992,1991;Child,Pollette,andFlosdorfKey:1986;CosulichAssociates1988;HDREngineering,Inc.rColdWinterLocationsjSummerResort1989;KillamAssociates1990;NorthHempstead1986;FIG.10.3.1Month-to-monthvariationinMSWgenerationOysterBay1987).Wastegenerationisrelativelylowinrate.thewinterbutriseswithtemperatureinthespring.Thesurgeofwastegenerationinthespringiscausedbothbyincreasedhumanactivity,includingspringcleaning,andandlocalfactorscancausethepeakofwastegenerationrenewedplantgrowthandassociatedyardwaste.Wastetooccurinanyseasonoftheyear.generationtypicallydeclinessomewhatafterJunebutre-mainsaboveaverageuntilmidtolatefall.Incontrast,Figure10.3.1alsoshowsthepatternofwastegenerationinCapeMayCounty,NewJersey,asummerresortareaComponentCompositionofMSW(CampDresser&McKeeInc.1991).Theannualinfluxoftouristsoverwhelmsallotherinfluencesofwastegen-Table10.3.1liststherepresentativecomponentcomposi-eration.tionforMSWdisposedintheUnitedStatesandadjacentAreaswithmildwintersmaydisplaymonth-to-monthportionsofCanadaandshowsrangesforindividualcom-patternsofwastegenerationsimilartothecold-winterpat-ponents.Materialsdivertedfromthewastestreamforre-ternshowninFigure10.3.1butwithasmallerdifferencecyclingorcompostingarenotincluded.Thetableisbasedbetweenthewinterandspring/summerrates.Ontheotherontheresultsoftwenty-twofieldstudiesinelevenstateshand,localfactorscancreateadistinctivepatternnotgen-plustheCanadianprovinceofBritishColumbia.Theerallyseeninotherareas,asinSarasota,Florida(Camprangesshowninthetableareannualvaluesforcounty-Dresser&McKeeInc.1990).Thesurgeofactivityandsizedareas.Seasonalvaluesmaybeoutsidetheseranges,plantgrowthinthespringislessmarkedinmildclimates,especiallyinindividualmunicipalities.©1999CRCPressLLC TABLE10.3.1REPRESENTATIVECOMPONENTResidentialMSWcontainsmorenewspaper;yardCOMPOSITIONOFMSWwaste;disposablediapers;andtextiles,rubber,andleather.NonresidentialMSWcontainsmorecorrugatedcard-Rangeofboard,high-gradepaper,wood,otherplastics,andotherRepresentativeReasonableCompositionReportedmetals.WasteCategory(%)bValues(%)bThecompositionofMSWvariesfromoneCIIestab-lishmenttoanother.However,virtuallyallbusinessesandOrganics/Combustibles86.6—institutionsgenerateavarietyofwastematerials.Forex-Paper39.8—Newspaper6.84.0–13.1ample,officesdonotgenerateonlypaperwaste,andCorrugated8.63.5–14.8restaurantsdonotgenerateonlyfoodwaste.Kraft1.50.5–2.3Corrugated&kraft10.15.4–15.6aOtherpaper22.917.6–30.6ComponentCompositionofBulkyHigh-gradepaper1.70.6–3.2aWasteOtherpaper21.216.9–25.4Magazines2.11.0–2.9Otherpapera19.112.5–23.7FewercompositiondataareavailableforbulkywastethanOfficepaper3.42.5–4.5forMSW.Table10.3.2showsthepotentialrangeofcom-Magazines&mail4.03.6–5.7positions.Thefirstcolumninthetableshowsthecom-aOtherpaper17.2—positionofallbulkywastegeneratedintwoadjacentcoun-Yardwaste9.72.8–19.6tiesinsouthernNewJersey,includingbulkywasteGrassclippings4.00.3–6.5Otheryardwaste5.7—reportedasrecycled.Thethirdcolumnshowsthecompo-Foodwaste12.06.8–17.3sitionofbulkywastedisposedinthetwocounties,andthePlastic9.46.3–12.6middlecolumnshowstheestimatedrecyclingrateforeachPolyethyleneterephthalate0.40.1–0.5bulkywastecomponentbasedonreportedrecyclingand(PET)bottlesdisposal.NotethattheestimatedoverallrecyclingrateisHigh-densitypolyethylene0.70.4–1.1(HDPE)bottlesalmost80%.Otherplastic8.35.8–10.2Thecompositionpriortorecyclingisdramaticallydif-Polystyrene1.00.5–1.5ferentfromthecompositionafterrecycling.Forexample,Polyvinylchloride(PVC)0.060.02–0.10inorganicmaterialsaccountforroughlythreequartersofbottlesathebulkywastebeforerecyclingbutlittlemorethanoneOtherplastic7.25.3–9.5Polyethylenebags&film3.73.5–4.0quarterafterrecycling.Dependingonlocalrecyclingprac-atices,thecompositionofbulkywastereceivedatadisposalOtherplastic3.52.8–4.4Otherorganics15.7—facilityintheUnitedStatescouldbesimilartothefirstcol-Wood4.01.0–6.6umnofTable10.3.2,similartothethirdcolumn,orany-Textiles3.51.5–6.3whereinbetween.Textiles/rubber/leather4.52.6–9.2Fines3.32.8–4.0ThecompositionofMSWdoesnotchangedramaticallyFines,Asinch2.21.7–2.8fromseasontoseason.Eventhemostvariablecomponent,Disposablediapers2.51.8–4.1yardwaste,maybeconsistentinareaswithmildclimates.Otherorganics1.4—Inareaswithcoldwinters,generationofyardwastegen-Inorganics/Noncombustibles13.4—erallypeaksinthelatespring,declinesgraduallythroughMetal5.8—Aluminum1.00.6–1.2thesummerandfall,andislowestinJanuaryandFebru-Aluminumcans0.60.3–1.2ary.AsurgeinyardwastecanoccurinmidtolatefallinOtheraluminum0.40.2–0.9areaswherealargeproportionoftreeleavesenterthesolidTin&bimetalcans1.50.9–2.7wastestreamandarenotdivertedforcompostingoraOthermetal3.31.1–6.9mulching.Ferrousmetal4.52.8–5.5Glass4.82.3–9.7Food&beverage4.32.0–7.7containersDensityOtherglass0.5—Batteries0.10.04–0.10AsdiscussedinSection10.2,thedensityofMSWvariesOtherInorganicsaccordingtocircumstance.Table10.3.3showsrepresen-Withnoncontainerglass3.21.9–4.9tativedensityrangesforMSWunderdifferentconditions.Withoutnoncontainerglass2.71.8–3.8ThedensityofmixedMSWisinfluencedbythedegreeofaEach“other”categorycontainsallmaterialofitstypeexceptmaterialinthecompaction,moisturecontent,andcomponentcomposi-categoriesaboveit.tion.Asshowninthetable,individualcomponentsofbWeightpercentageMSWhavedifferentbulkdensities,andarangeofdensi-tiesexistswithinmostcomponents.©1999CRCPressLLC TABLE10.3.2COMPONENTCOMPOSITIONOFBULKYWASTEANDTHEPOTENTIALIMPACTOFRECYCLINGCompositionCompositionCompositionofallofBulkyofBulkyBulkyWasteWasteWasteGeneratedRecycledLandfilledWasteCategory(%)a(%)a(%)aOrganics/Combustibles24.737.973.4Lumber13.147.233.0Corrugatedcardboard0.72.53.1Plastic1.018.83.7Furniture1.30.06.3Vegetativematerials3.873.04.9Carpet&padding0.70.03.2Bagged&miscellaneous2.10.010.2Roofingmaterials1.20.45.9Tires0.3100.00.0Other0.60.03.1Inorganics/Noncombustibles75.392.626.6Gypsumboard&plaster1.83.98.3Metal&appliances15.492.55.5Dirt&dust1.20.05.8Concrete26.596.74.2Asphalt28.799.90.1Bricks&blocks1.381.81.1Other0.30.01.6Overall100.079.1100.0Sources:DatafromCampDresser&McKee,1992,AtlanticCounty(NJ)SolidWasteCharacterizationProgram(Edison,N.J.[May])andIdem,1991,CapeMayCountyMulti-SeasonalSolidWasteCompositionStudy(Edison,N.J.[August]).aWeightpercentageTABLE10.3.3DENSITYOFMSWANDWithinindividualcategoriesofMSW,bulkdensityin-COMPONENTScreasesasphysicalirregularitydecreases.Compactionin-creasesdensityprimarilybyreducingirregularity.SomeDensitycompactionoccursinpiles,sodensitytendstoincreaseasMaterialandCircumstance(lb/cuyd)theheightofapileincreases.Inmostcases,shreddingandMixedMSWothersizereductionmeasuresalsoincreasedensitybyre-Loose150–300ducingirregularity.ThesizereductionofregularlyshapedIncompactortruck400–800materialssuchasofficepaper,however,canincreaseir-Dumpedfromcompactortruck300–500regularityanddecreasedensity.Baled0800–1600Inlandfill0800–1400ParticleSize,Abrasiveness,andLooseBulkDensitiesAluminumcans(uncrushed)54–81OtherPhysicalCharacteristicsCorrugatedcardboard050–135Dirt,sand,gravel,concrete2000–3000Figure10.3.2showsarepresentativeparticlesizedistribu-Foodwaste0800–1500tionforMSWbasedonresearchbyHilton,Rigo,andGlassbottles(whole)400–600Chandler(1992).Environmentalengineersgenerallyesti-Lightferrous,includingcans100–250matesizedistributionbypassingsamplesofMSWoveraMiscellaneouspaper080–250seriesofscreens,beginningwithafinescreenandwork-Stackedhigh-gradepaper400–600inguptoacoarsescreen.Asshowninthefigure,MSWPlastic060–150hasnocharacteristicparticlesize,andmostcomponentsRubber200–400ofMSWhavenocharacteristicparticlesize.Textiles060–180MSWdoesnotflow,andpilesofMSWhaveaten-Wood200–600dencytoholdtheirshape.LoadsofMSWdischargedfromYardwaste100–600compactortrucksoftenretainthesameshapetheyhadin-©1999CRCPressLLC 100908070Key:6010"Screen8"Screen6"Screen504"Screen2"Screen401"Screen0.5"ScreenPercentPassingScreen3020100PaperPlasticGlassOtherDiapersOverallBatteriesFoodWasteYardWasteOtherOrganicMagneticMetalNonmagneticMetalWasteCategoryFIG.10.3.2RepresentativesizedistributionofMSW.(AdaptedfromD.Hilton,H.G.Rigo,andA.J.Chandler,1992,Compositionandsizedistributionofablue-boxseparatedwastestream,presentedatSWANA’sWaste-to-EnergySymposium,Minneapolis,MN,January1992.)sidethetruck.WhenMSWisremovedfromonesideofsolidwasteisdefinedasthemateriallostduringonehourastoragebunkeratanMSWcombustionfacility,thewasteat105°C.Ashistheresidueremainingaftercombustion.ontheothersidegenerallydoesnotfallintothevacatedTogether,moistureandashrepresentthenoncombustiblespace.Thischaracteristicallowsthesideonwhichtrucksfractionofthewaste.dumpwastebekeptrelativelyemptyduringthehoursVolatilematteristhematerialdrivenoffasgasorva-whenthefacilityreceiveswaste.porwhenwasteissubjectedtoatemperatureofapprox-MSWtendstostratifyverticallywhenmixed,withimately950°Cfor7minbutispreventedfromburningsmalleranddenserobjectsmigratingtowardthebottombecauseoxygenisexcluded.Volatilemattershouldnotbeandlighterandbulkierobjectsmovingtowardthetop.confusedwithvolatileorganiccompounds(VOCs).VOCsHowever,MSWdoesnotstratifymuchwhenmerelyvi-areasmallcomponentoftypicalsolidwaste.Inproximatebrated.analysis,anyVOCspresenttendtobeincludedinthere-AlthoughMSWisconsideredsoftandmushy,itcon-sultformoisture.tainssubstantialquantitiesofglass,metal,andotherpo-Conceptually,fixedcarbonisthecombustiblematerialtentiallyabrasivematerials.remainingafterthevolatilematterisdrivenoff.Fixedcar-bonrepresentstheportionofcombustiblewastethatmustbeburnedinthesolidstateratherthanasgasorvapor.CombustionCharacteristicsThevalueforfixedcarbonreportedbythelaboratoryisMostlaboratoryworkperformedonsamplesofsolidcalculatedasfollows:wasteovertheyearshasfocusedonparametersrelatedto%fixedcarbon5100%2%moisturecombustionandcombustionproducts.Thestandardlab-2%ash2%volatilematter10.3(1)oratorytestsinthiscategoryareproximatecomposition,ultimatecomposition,andheatvalue.Table10.3.4showsarepresentativeproximatecom-positionforMSW.Thevaluesinthetablearepercentagesbasedondry(moisture-free)MSW.Representativemois-PROXIMATECOMPOSITIONturevaluesarealsoprovided.ThesemoisturevaluesareTheelementsofproximatecompositionaremoisture,ash,forMSWandcomponentsofMSWastheyarereceivedvolatilematter,andfixedcarbon.Themoisturecontentofatadisposalfacility.Becauseofashortageofdataforthe©1999CRCPressLLC proximatecompositionofnoncombustiblematerials,thesediscardedwithfoodwaste.Thispaperincludesnewspa-materialsarepresentedas100%ash.per,kraftpaper,andasubstantialportionofotherpaperThedry-basisvaluesinTable10.3.4canbeconvertedfromresidentialsourcesaswellascorrugatedcardboardtoas-receivedvaluesbyusingthefollowingequation:fromcommercialsources.Othersourcesofmoistureinpaperwasteincludewa-A5D(100%2M)10.3(2)terabsorbedbypapertowels,napkins,andtissuesduringwhere:use,andprecipitation.Absorbentmaterialsfrequentlyex-posedtoprecipitationincludenewspaperandcorrugatedA5valueforwasteasreceivedatthesolidwastefacil-cardboard.Manytrashcontainersareleftuncovered,andityprecipitationisabsorbedbythewaste.StandingwaterinD5dry-basisvaluedumpstersisoftentransferredtothecollectionvehicle.M5percentmoistureforwastereceivedatthesolidThevalueofproximateanalysisislimitedbecause(1)wastefacilityitdoesnotindicatethedegreeofoxidationofthecom-Betweeninitialdiscardatthepointofgenerationandbustiblewasteand(2)itgiveslittleindicationofthequan-deliverytoacentralfacility,moisturemovesfromwetma-titiesofpollutantsemittedduringcombustionofthewaste.terialstodryandabsorbentmaterials.Thelargestmove-Ultimateanalysissupplementstheinformationprovidedmentofmoistureisfromfoodwastetouncoatedpaperbyproximateanalysis.TABLE10.3.4REPRESENTATIVEPROXIMATEANDULTIMATECOMPOSITIONOFMSWProximateComposition—DryBasisaUltimateComposition—DryBasisVolatileFixedAshMatterCarbonCarbonHydrogenNitrogenChlorineSulfurOxygenMoistureWasteCategory(%)(%)(%)(%)(%)(%)(%)(%)(%)(%)Organics/Combustibles7.782.69.648.66.80.940.690.2235.032.5Paper6.383.510.143.06.00.360.170.1743.824.0Newspaper5.283.811.143.85.90.290.140.2444.423.2Corrugated&kraftpaper2.285.812.146.06.40.280.140.2244.821.2High-gradepaper9.183.47.538.15.60.150.120.0746.99.3Magazines20.471.87.935.05.00.050.070.0839.48.6Otherpaper6.983.89.342.76.10.500.220.1443.328.7Yardwaste9.673.017.445.05.61.50.310.1737.753.9Grassclippings9.775.614.743.35.92.60.600.3037.663.9Leaves7.372.720.150.05.70.820.100.1036.044.0Otheryardwaste12.570.517.040.75.01.30.260.1040.050.1Foodwaste11.079.010.045.46.93.30.740.3232.365.4Plastic5.393.01.376.311.50.262.40.204.413.3PETbottles1.395.03.668.58.00.160.080.0821.93.6HDPEbottles2.497.40.281.613.60.100.180.201.97.0Polystyrene1.897.80.486.37.90.280.120.303.410.8PVCbottles0.646.23.244.25.90.2640.10.897.63.2Polyethylenebags&film8.890.11.177.412.90.100.090.121.819.1Otherplastic4.294.11.772.911.40.455.30.245.510.5OtherOrganics11.377.810.946.26.11.91.00.3633.327.3Wood2.883.014.146.76.00.710.120.1643.414.8Textiles/rubber/leather6.684.09.450.36.43.31.80.3331.312.4Fines25.364.710.037.35.31.60.540.4529.541.1Disposablediapers4.187.18.748.47.60.510.230.3538.866.9Otherorganics31.358.89.944.25.31.82.20.8114.48.0bInorganics/Noncombustibles100000000000Overall24.967.27.839.55.60.760.560.1828.528.2aAlsoincludesashvaluesfromfirstcolumnofproximateanalysis.bValuesassumedforthepurposeofestimatingoverallvalues.©1999CRCPressLLC ULTIMATECOMPOSITIONNoncombustiblescategory,whichisshownas100%ashbecauseofalackofdataontheultimatecomposition.Moistureandash,aspreviouslydefinedforproximateTheinorganic(noncombustible)wastecategoriescon-composition,arealsoelementsofultimatecomposition.IntributemostoftheashinMSW.Additionalashiscon-standardultimateanalysis,thecombustiblefractionisdi-tributedbytheinorganiccomponentsofcombustiblema-videdamongcarbon,hydrogen,nitrogen,sulfur,andoxy-terials,includingclayinglossyandhigh-gradepaper,dirtgen.Ultimateanalysisofsolidwasteshouldalsoincludeinyardwaste,bonesandshellsinfoodwaste,asbestosinchlorine.Theresultsaremoreusefulifsulfurisbrokenvinyl–asbestosfloorcoverings,fiberglassinreinforcedplas-downintoorganicsulfur,sulfide,andsulfate;andchlo-tic,andgritonroofingshingles.rineisbrokendownintoorganic(insoluble)andinorganic(soluble)chlorine(Niessen1995).HEATVALUECarbon,hydrogen,nitrogen,sulfur,andchlorinearemeasureddirectly;calculatingoxygenrequiressubtractingTable10.3.5showstheheatvalueoftypicalMSWbasedthesumoftheothercomponents(includingmoistureandontheresultsoflaboratorytestingofMSWcomponents.ash)from100%.Table10.3.4showsarepresentativeul-Calculationsoftheheatvaluebasedonenergyoutputmea-timatecompositionforMSW.Thedry-basisvaluesshownsurementsatoperatingcombustionfacilitiesgenerallyyieldinthetablecanbeconvertedtoas-receivedvalueswithlowervalues(seeSection10.5).useofEquation10.3(2).TheheatvalueshownforsolidwasteandconventionalTheultimatecompositionofMSWonadrybasisre-fuelsintheUnitedStates,Canada,andtheUnitedflectsthedominanceofsixtypesofmaterialsinMSW:cel-Kingdomistypicallythehigherheatingvalue(HHV).Thelulose,lignins,fats,proteins,hydrocarbonpolymers,andHHVincludesthelatentheatofvaporizationofthewa-inorganicmaterials.Celluloseisapproximately42.5%car-tercreatedduringcombustion.Whenthisheatisdeducted,bon,5.6%hydrogen,and51.9%oxygenandaccountsfortheresultiscalledthelowerheatingvalue(LHV).Forad-themajorityofthedryweightofMSW.Thecellulosecon-ditionalinformationseeNiessen(1995).tentofpaperrangesfromapproximately75%forlowTheas-receivedheatvalueisroughlyproportionaltogradestoapproximately90%forhigh-gradepaper.Woodthepercentageofwastethatiscombustible(i.e.,neitherisroughly50%cellulose,andcelluloseisamajoringre-moisturenorash)andtothecarboncontentofthecom-dientofyardwaste,foodwaste,anddisposablediapers.bustiblefraction.TheheatvaluesoftheplasticscategoriesCotton,thelargestingredientofthetextilecomponentofarehighestbecauseoftheirhighcarboncontent,lowashMSW,isapproximately98%cellulose(Masterton,content,andlow-to-moderatemoisturecontent.Papercat-Slowinski,andStanitski1981).egorieshaveintermediateheatvaluesbecauseoftheirin-Despitetheabundanceofcellulose,MSWcontainstermediatecarboncontent,moderatemoisturecontent,morecarbonthanoxygenduetothefollowingfactors:andlow-to-moderateashcontent.Yardwaste,foodwaste,anddisposablediapershavelowheatvaluesbecauseof•MostoftheplasticfractionofMSWiscomposedtheirhighmoisturelevels.ofpolyethylene,polystyrene,andpolypropylene,whichcontainlittleoxygen.Bioavailability•Syntheticfibers(textilescategory)containmorecarbonthanoxygen,andrubbercontainslittleBecausemicroorganismscanmetabolizepaper,yardwaste,oxygen.foodwaste,andwood,thiswasteisclassifiedasbiodegrad-•Thelowergradesofpapercontainsignificantable.Disposablediapersandtheircontentsarealsolargelyquantitiesoflignins,whichcontainmorecarbonbiodegradable,asarecottonandwooltextiles.thanoxygen.Somebiodegradablewastematerialsaremorereadily•Fatscontainmorecarbonthanoxygen.metabolizedthanothers.Themostreadilymetabolizedmaterialsarethosewithhighnitrogenandmoisturecon-Thenitrogeninsolidwasteisprimarilyinorganicform.tent:foodwaste,grassclippings,andothergreen,pulpyThelargestcontributorsofnitrogentoMSWarefoodyardwastes.Thesewastesareputrescibleandhavehighwaste(proteins),grassclippings(proteins),andtextilesbioavailability.Leafwastegenerallyhasintermediate(wool,nylon,andacrylic).Chlorineoccursinbothorganicbioavailability.Wood,cottonandwool,althoughandinorganicforms.Thelargestcontributoroforganicbiodegradable,haverelativelylowbioavailabilityandarechlorineisPVCorvinyl.MostofthePVCisintheotherconsiderednoncompostablewithinthecontextofsolidplasticandtextilescomponents.Thelargestsourceofin-wastemanagement.organicchlorineissodiumchloride(tablesalt).SulfurisnotabundantinanycategoryofcombustibleMSWbutisToxicSubstancesinSolidWasteamajorcomponentofgypsumboard.Thesulfuringyp-sumislargelynoncombustiblebutnotentirelyso.InTableSolidwasteinevitablycontainsmanyofthetoxicsub-10.3.4,gypsumboardisincludedintheInorganics/stancesmanufacturedorextractedfromtheearth.Most©1999CRCPressLLC aTABLE10.3.5REPRESENTATIVEHEATVALUESOFMSWDry-BasisAs-ReceivedHeatValueMoistureHeatValueWasteCategory(HHVinBtu/lb)Content(%)(HHVinBtu/lb)Organics/Combustibles915432.56175Paper758724.05767Newspaper773323.25936Corrugated&kraft816821.26435High-gradepaper65509.35944Magazines58268.65326Otherpaper755828.75386Yardwaste773153.93565Grassclippings770363.92782Leaves803044.04499Otheryardwaste738750.13689Foodwaste899365.43108Plastic16,49913.314,301PETbottles13,7613.613,261HDPEbottles18,8287.017,504Polystyrene16,97310.815,144PVCbottles10,1603.29838Polyethylenebags17,10219.113,835&filmOtherplastic15,76210.514,108Otherorganics869827.36322Wood843014.87186Textiles/rubber/997512.48733leatherFines697841.14114Disposablediapers972166.93222Otherorganics74388.06844Inorganics/00.00bNoncombustiblesOverall744628.25348aValuesshownareHHV.InHHVmeasurements,theenergyrequiredtodriveoffthemoistureformedduringcombustionisnotdeducted.bValuesassumedforthepurposeofestimatingoverallvalues.toxicmaterialinsolidwasteisinoneofthreecategories:FranklinAssociates,Ltd.(1989)providedextensivein-formationonsourcesofleadandcadmiuminMSW,and•ToxicmetalsRuggandHanna(1992)compileddetailedinformationon•Toxicorganiccompounds,manyofwhicharealsosourcesofleadinMSWintheUnitedStates.flammableMostMSWreferredtoashouseholdhazardouswaste•Asbestosissoclassifiedbecauseitcontainstoxicorganiccom-Theresultsofstudiesoftoxicmetalsinsolidwastevary.pounds.LargequantitiesoftoxicorganicmaterialsfromTable10.3.6summarizesselectedresultsoftwocompre-commercialandindustrialsourceswereoncedisposedinhensivestudiesperformedinCapeMayCounty,NewMSWlandfillsintheUnitedStates,andmanyoftheseJersey(CampDresser&McKeeInc.1991a)andBurnaby,landfillsarenowofficiallydesignatedashazardouswasteBritishColumbia(Chandler&Associates,Ltd.1993;sites.Thelarge-scaledisposaloftoxicorganicsinMSWRigo,Chandler,andSawell1993).Reportsofbothstud-landfillshasbeenlargelyeliminated,butdisposalofhouse-iescontaindataforadditionalmetalsandmaterials,andholdhazardouswasteremainsaconcernformany.theBurnabyreportscontainresultsfornumeroussubcat-Generally,householdhazardouswastereferstowhateveregoriesofthecategoriesinthetable.TheBurnabyreportstoxicmaterialsremaininMSW,regardlessofthesource.alsoanalyzethebehaviorofspecificmetalsfromwasteEstimatesoftheabundanceofhouseholdhazardouscomponentsduringprocessinginanMSWincinerator.wastevary.Reasonsforthelackofconsistencyfromone©1999CRCPressLLC a©1999CRCPressLLCTABLE10.3.6REPORTEDMETALCONCENTRATIONSINCOMPONENTSOFMSWArsenicCadmiumChromiumCopperLeadMercuryNickelZincWasteCategoryCMBCCMBCCMBCCMBCCMBCCMBCCMBCCMBCOrganics/CombustiblesPaperbNewspaper0.10.7ND0.1ND491718ND70.32ND285821Corrugatedcardboard0.20.6ND0.1ND21331940.20.1645610Kraftpaper0.30.8ND0.15511111590.10.5ND83022High-gradepaper0.71ND0.1ND378ND50.10.3ND828208Magazines0.41ND0.24114632ND30.090.3ND138827Other0.41ND1427522591820.070.3ND75871Yardwaste0.96ND548710571141370.1132189321Foodwaste0.11ND2ND23943ND720.020.32520186PlasticPETND0.8ND51517303159620.070.2ND82197HDPE0.20.5ND352151424211610.10.2ND758142Film0.50.6ND510010225234503250.10.2ND7120658Other0.40.78827279858193420.040.3ND4069231OtherorganicsWood3424ND0.45277326810840820.3ND3205174Textiles&footwear0.80.41943876192562481290.3151666222Fines3714141151792432732590.211854352654Disposablediapers0.1—ND—1—2—ND—0.02—ND—28—Inorganics/NoncombustiblesMetalFerrousfood&beveragecans4716435271913751043503420.861331611451552AluminumbeveragecansND0.4ND57291107110530410.70.4542180229Othermetal928022254702768681620821279950.70.4411241675199,000Glassfood&beveragecontainersND2ND4ND91ND26841030.20.2ND15ND71HouseholdbatteriescCarbon-zinc&alkalinebatteries72531027455784006328236942900136—512180,000103,000Nickel-cadmiumbatteries—4175,000120,000—64—53—113—0.3240,000315—685Otherinorganics112ND8219113113506070.90.2573211997Source:DataadaptedfromCampDresser&McKeeInc.,1991a,CapeMayCountymulti-seasonalsolidwastecompositionstudy(Edison,N.J.[August]);A.J.Chandler&Associates,Ltd.etal.,1993,Wasteanalysis,sam-pling,testingandevaluation(WASTE)program:EffectofwastestreamcharacteristicsonMSWincineration:Thefateandbehaviourofmetals.FinalreportofthemassburnMSWincinerationstudy(Burnaby,B.C.),Vol.1,Summaryreport(Toronto[April]);andH.G.Rigo,A.J.Chandler,andS.E.Sawell,1993,Debunkingsomemythsaboutmetals,inProceedingsofthe1993InternationalConferenceonMunicipalWasteCombustion(Williamsburg,Va.[30March–2April]).aAllvaluesinmg/kgonanas-receivedbasis.ValuespresentedarebasedonreportedresultsfromstudiesinCapeMayCounty,NewJerseyandBurnaby,BritishColumbia.CMindicatesCapeMay,andBCindicatesBurnaby.bND5Notdetected.cCurrentvaluesformercuryareclosetoorbelowtheBurnabyvalue. studytoanotherincludethefollowing:———.1991b.CumberlandCounty(NJ)wasteweighingandcomposi-tionanalysis.Edison,N.J.(January).Somequantityestimatesincludelesstoxicmaterialssuch———.1992.AtlanticCounty(NJ)solidwastecharacterizationpro-aslatexpaint.gram.Edison,N.J.(May).Mostquantityestimatesincludetheweightofcontainers,Chandler,A.J.,&Associates,Ltd.etal.1993.Wasteanalysis,sampling,testingandevaluation(WASTE)program:EffectofwastestreamandmanyestimatesincludethecontainerseveniftheycharacteristicsonMSWincineration:Thefateandbehaviourofmet-areempty.als.FinalreportofthemassburnMSWincinerationstudy(Burnaby,Somequantityestimatesincludematerialsthatwereorig-B.C.).VolumeI,Summaryreport.Toronto(April).inallyinliquidorpasteformbuthavedried,suchasChild,D.,G.A.Pollette,andH.W.Flosdorf.1986.Wastestreamanaly-driedpaintandadhesives.Toxicsubstancescanstillsis.WasteAge(November).Cosulich,WilliamF.,Associates,P.C.1988.Solidwastemanagementleachfromthesedriedmaterials,butdryingreducestheplan,CountyofMonroe,NewYork:Solidwastequantificationandpotentialleachingrate.characterization.Woodbury,N.Y.(July).FranklinAssociates,Ltd.1989.CharacterizationofproductscontainingStronglytoxicorganicmaterials,excludingtheircon-leadandcadmiuminmunicipalsolidwasteintheUnitedStates,1970tainers,appeartoconstitutewellunder0.5%ofMSW,to2000.U.S.EPA(January).andthetoxicmaterialisusuallydispersed.BulkywasteHDREngineering,Inc.1989.Reportonsolidwastequantities,compo-typicallycontainsnomoretoxicorganicmaterialthansitionandcharacteristicsforMonmouthCounty(NJ)wasterecoveryMSW,butbulkywasteismorelikelytocontainconcen-system.WhitePlains,N.Y.(March).KillamAssociates.1990.SomersetCounty(NJ)solidwastegenerationtratedpocketsoftoxicsubstances.andcompositionstudy.Millburn,N.J.(May).AstatewidewastecharacterizationstudyinMinnesotaMasterton,W.L.,E.J.Slowinski,andC.L.Stanitski.1981.Chemicalprin-(MinnesotaPollutionControlAgency1992;Minnesotaciples.5thed.Philadelphia:SaundersCollegePublishing.PollutionControlAgencyandMetropolitanCouncilMinnesotaPollutionControlAgency.1992.Minnesotasolidwastecom-1993)providesadetailedaccountingofthehouseholdhaz-positionstudy,1990–1991partI.SaintPaul,Minn.(November).MinnesotaPollutionControlAgencyandMetropolitanCouncil.1993.ardouswastematerialsencountered.Minnesotasolidwastecompositionstudy,1991–1992partII.SaintMostoftheasbestosinnormalsolidwasteisinoldPaul,Minn.(April).vinyl–asbestosfloorcoveringsandasbestosshingles.Niessen,W.R.1995.Combustionandincinerationprocesses:Asbestosintheseformsisgenerallynotasignificanthaz-Applicationsinenvironmentalengineering.2ded.NewYork:Marcelard.Dekker,Inc.NorthHempstead,Townof(NY),transferstationscalehouserecords,August1985throughJuly1986.1986.OysterBay,Townof(NY),transferstationscalehouserecords,—F.MackRuggSeptember1986throughAugust1987.1987.Rigo,H.G.,A.J.Chandler,andS.E.Sawell.Debunkingsomemythsaboutmetals.InProceedingsofthe1993InternationalConferenceonMunicipalWasteCombustion,Williamsburg,VA,March30–AprilReferences2,1993.Rugg,M.andN.K.Hanna.1992.MetalsconcentrationsincompostableCampDresser&McKeeInc.1990.SarasotaCountywastestreamcom-andnoncompostablecomponentsofmunicipalsolidwasteinCapepositionstudy.Draftreport(March).MayCounty,NewJersey.ProceedingsoftheSecondUnitedStates———.1991a.CapeMayCountymulti-seasonalsolidwastecomposi-ConferenceonMunicipalSolidWasteManagement,Arlington,VA,tionstudy.Edison,N.J.(August).June2–5,1992.©1999CRCPressLLC 10.4CHARACTERIZATIONMETHODSThissectiondescribesandevaluatesmethodsforestimat-fundamentalmethodscreateshybridmethodologies(foringthecharacteristicsofsolidwaste.Thepurposesofwasteexample,seeGay,Beam,andMar[1993]).characterizationareidentified;andmethodsforestimat-Thedirectfieldstudyofwasteissuperiorinconcept,ingquantity,composition,combustioncharacteristics,andbutstatisticallymeaningfulfieldstudiesareexpensive.Formetalsconcentrationsareaddressed.example,abudgetof$100,000istypicallyrequiredforadetailedestimateofthecompositionofMSWarrivingatasingledisposalfacility,accuratetowithin10%at90%PurposesofSolidWasteconfidence.Askilledandexperiencedteamcanoftenpro-videadditionalinformationatlittleadditionalcost,in-CharacterizationcludinganestimatedcompositionforbulkywastebasedThegeneralpurposeofsolidwastecharacterizationistoonvisualobservation.promotesoundmanagementofsolidwaste.Specifically,Theprincipaladvantageofthematerialflowsmethod-characterizationcandeterminethefollowing:ologyisthatitdrawsonexistingdatathatareupdatedregularlybybusinessorganizationsandgovernments.ThisThesize,capacity,anddesignoffacilitiestomanagethemethodhasseveralpositiveeffects.First,theentirewastewaste.streamismeasuredinsteadofsamplesofthewaste,asinThepotentialforrecyclingorcompostingportionsofthefieldstudies.Therefore,theresultsofproperlyconductedwastestream.materialflowsstudiestendtobemoreconsistentthantheTheeffectivenessofwastereductionprograms,recyclingresultsoffieldstudies.Second,updatesofmaterialflowsprograms,orbansonthedisposalofcertainmaterials.studiesarerelativelyinexpensiveoncetheanalyticalstruc-Potentialsourcesofenvironmentalpollutioninthewaste.tureisestablished.Third,materialflowsstudiesaresuitedInpractice,theimmediatepurposeofmostwastechar-totrackingeconomictrendsthatinfluencethesolidwasteacterizationstudies,includingmanyextensivestudies,istostream.complywithspecificregulatorymandatesandtoprovideTheprincipaldisadvantagesofmaterialflowsmethod-informationforusebyvendorsinpreparingbidstode-ologyfollow.sign,construct,andoperatesolidwastemanagementfa-Obtainingcompleteproductiondataforeveryitemdis-cilities.cardedassolidwasteisdifficult.Thepurposesofawastecharacterizationprogramde-Althoughdataonfoodsalesareavailable,foodsalesbearterminethedesignofit.Ifallwasteistobelandfilled,thelittlerelationtothegenerationoffoodwaste.Notonlycharacterizationprogramshouldfocusonthequantityofismostfoodnotdiscarded,butsignificantquantitiesofwaste,itsdensity,anditspotentialforcompaction.Thewaterareaddedtoorremovedfrommanyfooditemscompositionofthewasteanditschemicalcharacteristicsbetweenpurchaseanddiscard.Thesefactorsvaryfromarerelativelyunimportant.Ifallwasteistobeincinerated,oneareatoanotherbasedonlocalfoodpreferencesandthecriticalparametersarequantity,heatvalue,andtheeatingpatterns.percentageofcombustiblematerialinthewaste.Ifrecy-Materialflowsmethodologycannotmeasurethegenera-clingandcompostingareplannedorunderway,acom-tionofyardwaste.positionstudycanidentifythematerialstargetedforre-Materialflowsmethodologydoesnotaccountforthead-covery,estimatetheirabundanceinthewaste,andmonitorditionofnonmanufacturedmaterialstosolidwastecompliancewithsourceseparationrequirements.priortodiscard,includingwater,soil,dust,petdrop-pings,andthecontentsofuseddisposablediapers.Someofthematerialcategoriesusedinmaterialflowsstud-BasicCharacterizationMethodsiesdonotmatchthecategoriesofmaterialstargetedforrecycling.Forexample,advertisinginsertsinnewspa-Environmentalengineersuseoneoftwofundamentalpersaretypicallyrecycledwiththenewsprint,butinmethodstocharacterizesolidwaste.Onemethodistocol-materialflowsstudiestheinsertsarepartofaseparatelectandanalyzedataonthemanufactureandsaleofprod-commercialprintingcategory.uctsthatbecomesolidwasteafteruse.Themethodiscalledmaterialflowsmethodology.Thesecondmethodisadi-InperformingmaterialflowsstudiesfortheU.S.EPA,rectfieldstudyofthewasteitself.CombiningthesetwoFranklinAssociatesbasesitsestimatesoffoodwaste,yard©1999CRCPressLLC waste,andmiscellaneousinorganicwastesonfieldstud-Portabletruckscalesareavailableinthreebasiccon-iesinwhichsamplesofwasteweresorted.Franklinfigurations:(1)platformscalesdesignedtoaccommodateAssociates(1992)alsoadjustsitsdatafortheproductionentirevehicles(ortrailers),(2)axlescalesdesignedtoac-ofdisposablediaperstoaccountforthematerialsaddedcommodateoneaxleorapairoftandemaxlesatatime,duringuse.and(3)wheelscalesdesignedtobeusedinpairstoac-Ingeneral,themorelocalandthemoredetailedawastecommodateoneaxleorapairoftandemaxlesatatime.characterizationstudyistobe,thegreateraretheadvan-Axlescalescanbeusedsinglyorinpairs.Similarly,eithertagesofadirectfieldstudyofthewaste.oneortwopairsofwheelscalescanbeused.Whenasin-gleaxlescaleorasinglepairofwheelscalesisused,addingtheresultsforindividualaxlesyieldstheweightoftheve-EstimationofWasteQuantityhicle.ThebestmethodforestimatingwastequantityistoinstallPlatformscalesaretheeasiesttouse,butthecostcanpermanentscalesatdisposalfacilitiesandweigheverybeprohibitive.Theuseofwheelscalestendstobediffi-truckonthewayinandagainonthewayout.Anin-cultandtimeconsuming.Thecostofaxlescalesissimi-creasingnumberofsolidwastedisposalfacilitiesarelartothatofwheelscales,andaxlescalesareeasiertouseequippedwithscales,butmanylandfillsstillarenot.thanwheelscales.TheuseofapairofportableaxlescalesIntheUnitedStates,facilitieswithoutscalesrecordin-isrecommendedintheMunicipalsolidwastesurveypro-comingwasteincubicyardsandchargetippingfeesbytocolpreparedfortheU.S.EPAbySCSEngineers(1979).thecubicyard.SinceestimatingthevolumeofwasteinaRegardlessofwhattypeofscaleisused,asolidbasethatclosedorcoveredvehicleorcontainerisdifficult,thevol-doesnotbecomesoftinwetweatherisrequired.umerecordedisusuallythecapacityofthevehicleorcon-Truckweighingsurveys,likeotherwastecharacteriza-tainer.Becausethisestimationcreatesanincentivetode-tionfieldstudies,aretypicallyconductedduringallhoursliverwasteinfullvehicles,therecordedvolumestendtothatadisposalfacilityisopenduringafulloperatingweek.beclosetotheactualwastevolumes.Afullweekisusedbecausethevariationinwastechar-Forthereasonspreviouslystated,expressingwasteacteristicsisgreateramongthehoursofadayandamongquantityintonsispreferabletocubicyards.Thisconver-thedaysofaweekthanamongtheweeksofamonth.sionisconceptuallysimple,asshowninthefollowingAlso,spreadingthedaysoffieldworkoutoverseveralequation:weeksissubstantiallymoreexpensive.AtruckweighingsurveyshouldbeconductedduringM5VD/200010.4(1)atleasttwoweeks—oneweekduringtheperiodofmini-where:mumwastegenerationandoneweekduringtheperiodofmaximumwastegeneration(seeSection10.3).OneweekM5massofwasteintonsduringeachseasonoftheyearispreferable.HolidayweeksV5volumeofwasteincubicyardsshouldbeavoided.D5densityofwasteinpoundspercubicyardWeighingalltrucksenteringthedisposalfacilityisrarelyIfthedensityisexpressedintonspercubicyard,di-possible,soamethodoftruckselectionmustbechosen.vidingby2000isunnecessary.IntheUnitedStates,how-Aconceptuallysimpleapproachistoweigheverynthtruckever,thedensityofsolidwasteisusuallyexpressedin(forexample,every5thtruck)thatdeliverswastetothepoundspercubicyard.facility.ThisapproachassumesthatthetrucksweighedAlthoughsimpleconceptually,convertingcubicyardsrepresentalltrucksarrivingatthefacility.Thetotalwastetotonscanbedifficultinpractice.Thedensityofsolidtonnagecanbeestimatedwiththefollowingequation:wastevariesfromonetypeofwastetoanother,fromonetypeofvehicletoanother,andevenamongcollectionW5T(w/t)10.4(2)crews.Insmallwastestreams,localconditionscancausewhere:theoveralldensityofMSW,asreceivedatdisposalfacili-ties,tovaryfrom250to800lb/cuyd.Aconversionfac-W5thetotalweightofthewastedeliveredtothefacil-torof3.0to3.3cuyd/tn(600to667lb/cuyd)isreason-ityableforbothMSWandbulkywasteinmanylargewasteT5thetotalnumberoftrucksthatdeliveredwastetostreams;however,thisconversionfactormaynotberea-thefacilitysonableforaparticularwastestream.w5thetotalweightofthetrucksthatwereweighedAtdisposalfacilitieswithoutpermanentscales,envi-t5thenumberoftrucksthatwereweighedronmentalengineerscanuseportablescalestodevelopabetterestimateofthetonsofwastebeingdelivered.ThisapproachissuitedtoafacilitythatreceivesafairlySelectedtrucksareweighed,andenvironmentalengineersconstantflowoftrucks.Unfortunately,therateatwhichusetheresultstoestimatetheoverallweightofthewastetrucksarriveatmostfacilitiesfluctuatesduringtheoper-stream.atingday.Aweighingcrewtargetingeverynthtruckwill©1999CRCPressLLC misstrucksduringthebusypartsofthedayandbeidleThegreaterthevariationbetweensamples,themoresam-atothertimes.Missingtrucksduringthebusypartsoftheplesmustbesortedtoachieveagivenlevelofprecision.daycanbiastheresults;thetrucksthatarriveatthesetimesThegreaterthetimespentcollectingthesamples,thelesstendtobecurbsidecollectiontrucks,whichhaveadis-timeisavailabletosortthesamples.tinctiverangeofweights.Also,havingacrewanditsequip-Themorethewasteishandledpriortosorting,themorementstandidleatslowtimeswhilewaitingforthenthdifficultandlessprecisethesorting.trucktoarrivereducestheamountofdatacollected,whichAfundamentalquestionisthetimeperiod(s)overwhichreducesthestatisticalvalueoftheoverallresults.tocollectthesamples.One-weekperiodsaregenerallyusedAbetterapproachistoweighasmanytrucksaspos-becausemosthumanactivityandmostrefusecollectionsibleduringtheoperatingday,keepingtrackofthetotalschedulesrepeatonaweeklybasis.Samplingduringanumberoftrucksthatdeliverwasteduringeachhour.Aweekineachseasonoftheyearispreferable.Springsam-separateaveragetruckweightandtotalweightiscalcu-plingisparticularlyimportantbecausegenerationofyardlatedforeachhour,andthehourlytotalsareaddedtowaste,themostvariablewastecategory,isgenerallyleastyieldatotalfortheday.Forthispurpose,Equation10.4(2)inthewinterandgreatestinthespring.ismodifiedasfollows:AnotherfundamentalquestioniswhethertocollecttheW5T1(w1/t1)1T2(w2/t2)zzz1Tn(wn/tn)10.4(3)samplesattheplaceswherethewasteisgeneratedoratwhere:thesolidwastefacilitieswherethewasteistaken.Samplingatsolidwastefacilitiesisgenerallypreferred.CollectingW5thetotalweightofthewastedeliveredtothefacil-samplesatthepointsofgenerationmaybenecessaryun-ityderthefollowingcircumstances,however:T15thenumberoftrucksthatdeliveredwastetothefacilityinthefirsthourT25thenumberoftrucksthatdeliveredwastetotheTheprimaryobjectiveistocharacterizethewastegener-facilityinthesecondhouratedbycertainsources,suchasspecifictypesofbusi-Tn5thenumberoftrucksthatdeliveredwastetothenesses.facilityinthelasthouroftheoperatingdayTheidentityofthefacilitiestowhichthewasteistakenisw15thetotalweightofthetrucksthatwereweighedinnotknownorcannotbepredictedwithconfidenceforthefirsthouranygivenweek.w25thetotalweightofthetrucksthatwereweighedinThefacilitiesarewidelyspaced,increasingthedifficultythesecondhourandcostofthesamplingandsortingoperation.wn5thetotalweightofthetrucksthatwereweighedinAccesstothefacilitiescannotbeobtained.thelasthouroftheoperatingdaySufficientspacetosetupasortingoperationisnotavail-t15thenumberoftrucksthatwereweighedinthefirsthourableatthefacilities.t25thenumberoftrucksthatwereweighedinthesec-Appropriateloadsofwaste(e.g.,loadsfromthegeographicondhourareatobecharacterized)donotarriveatthefacilitiestn5thenumberoftrucksthatwereweighedinthelastfrequentlyenoughtosupportanefficientsamplingandhouroftheoperatingdaysortingoperation.Estimatingthestatisticalprecisionoftheresultsiscom-plexwhentheratiooftheweighedtruckstotheunweighedSamplingatthepointsofgenerationtendstobemoretrucksvariesfromhourtohour.(Klee[1991,1993]pro-expensiveandlessvalidthansamplingatsolidwastefa-videsadiscussionofthisstatisticalproblem.)cilities.Theaddedexpenseresultsfromtheincreasedef-fortrequiredtodesignthesamplingprotocolandthetraveltimeinvolvedincollectingthesamples.Thedecreasedvalidityofsamplingatthepointsofgen-SamplingMSWtoEstimateerationhastwoprincipalcauses.First,asignificantpor-Compositiontionofthewasteistypicallyinaccessible.Wastecanbein-accessiblebecauseitisonprivatepropertytowhichaccessAsinallstatisticalexercisesbasedonsampling,theac-isdeniedorbecauseitisintrashcompactors.Somewastequisitionofsamplesisacriticalstepinestimatingthecom-isinaccessibleduringthedaybecauseitisnotplacedinpositionofMSW.Theprincipalconsiderationsincollect-outdoortrashcontainersuntilafterbusinesshoursanditingsamplesarethefollowing:ispickedupearlyinthemorning.ThesecondmajorcauseEachpoundofwasteinthewastestreamtobecharacter-ofinaccuracyisthattherelativeportionofthewasteizedmusthaveanequalopportunitytoberepresentedstreamrepresentedbyeachtrashreceptacleisunknowninthefinalresults.becausethefrequencyofpickupandtheaveragequantityThegreaterthenumberofsamples,themoreprecisetheinthereceptacleateachpickupareunknown.Randomresults.selectionofreceptaclestobesampledresultsinunder-©1999CRCPressLLC samplingofthemoreactivereceptacles,whichrepresenttoensurethatspecificcollectionroutesarerepresentedinmorewaste.thesamples.PossiblemethodsforselectingtrucksintheTheseproblemsaregenerallylessacuteforresidentialfieldincludethefollowing:MSWthanforcommercialorinstitutionalMSW.ResidentialMSWisusuallyaccessibleforsamplingfrom•Constantintervalthecurboncollectiondayorfromdumpstersservingmul-•Progressofsorterstifamilyresidences.Becausehouseholdsgeneratesimilar•Randomnumbergeneratorquantitiesofwaste,randomselectionofhouseholdsfor•AllocationamongwastesourcessamplinggiveseachpoundofwasteasimilarprobabilityTheAmericanSocietyforTestingandMaterials(1992)ofbeingincludedinasample.Inaddition,becausewasteStandardtestmethodfordeterminationofthecomposi-characteristicsaremoreconsistentfromhouseholdtotionofunprocessedmunicipalsolidwaste(ASTMD5231)householdthanfrombusinesstobusiness,flawsinares-statesthatanyrandommethodofvehicleselectionthatidentialsamplingprogramaregenerallylesssignificantdoesnotintroduceabiasintotheselectionprocessisac-thanflawsinacommercialsamplingprogram.ceptable.AuniversalprotocolforsamplingsolidwastefromthePossibleconstantsamplingintervalsincludethefol-pointsofgenerationisimpossibletostatebecausecir-lowinginwhichnisanysetnumber:cumstancesvarygreatlyfromplacetoplaceandfromstudytostudy.Thefollowingaregeneralprinciplestofollow:•EverynthtruckCollectsamplesfromasmanydifferentsectorsofthetar-•Everynthtonofwastegetareaaspossiblewithoutoversamplingrelativelyin-•Everynthcubicyardofwastesignificantsectors.•AtruckeverynminutesIfpossible,collectsamplesfromcommerciallocationsinCollectingasamplefromeverynthtruckisrelativelyproportiontothesizeofthewastereceptaclesusedandsimplebutcausesthewasteinsmalltrucksandpartiallythefrequencyofpickup.fulltruckstobeoverrepresentedinthesamples.CollectingCollectsamplesfromsingle-familyandmultifamilyresi-asamplefromthetruckcontainingeverynthtonofwastedencesinproportiontothenumberofpeoplelivinginisidealbutisdifficultinpracticebecausetheweightofeachtypeofresidence(unlessamoresophisticatedba-eachtruckisnotapparentfromobservation.Collectingasisisreadilyavailable).Therequiredpopulationinfor-samplefromthetruckcontainingeverynthcubicyardofmationcanbeobtainedfromU.S.censuspublications.wasteismorefeasiblebecausethevolumetriccapacityofGivefieldpersonnelnodiscretioninselectinglocationsatmosttruckscanbedeterminedbyobservation.However,whichtocollectsamples.Forexample,fieldpersonnelbasingthesamplingintervalonvolumetriccapacitytendsshouldnotbetoldtocollectasamplefromElmStreettocauseuncompactedwasteandwasteinpartiallyfullbutrathertocollectasamplefromtheeastsideofElmtruckstobeoverrepresentedinthesamples.Street,startingwiththesecondhouse(orbusiness)BasingthesamplingintervaloneitherasetnumberofnorthfromParkStreet.trucksorasetquantityofwastecausesthepaceoftheTotheextentfeasible,addallwastefromeachselectedlo-samplingoperationtofluctuateduringeachdayoffieldcationtothesamplebeforegoingontothenextloca-work.Thisfluctuationcanresultininefficientuseofper-tion.Thispracticereducesthepotentialforsamplingbias.sonnelanddeviationsfromtheprotocolwhentargetedCollectingsamplesatsolidwastefacilitiesislessex-trucksaremissedattimesofpeakactivity.pensivethancollectingthematthepointsofgenerationCollectingasamplefromatruckeverynminutesiscon-andismorelikelytoproducevalidresults.Samplecollec-venientforsamplingpersonnelbutcausesthewasteintionatfacilitiesislessexpensivebecausenotravelisre-smalltrucksandpartiallyfulltruckstobeoverrepresentedquired.Samplescollectedatfacilitiesaremorelikelytoandthewasteintrucksthatarriveatbusytimestobeun-representthewastebeingcharacterizedbecausetheyarederrepresentedinthesamples.Thisapproachalsocausestypicallyselectedfromasinglelineoftrucksofknownsizeoverrepresentationofwastearrivinglateinthedaybe-thatcontaintheentirewastestream.causethetimeintervalbetweentruckstendstolengthenCollectingsamplesatsolidwastefacilitieshastwotowardtheendofthedayandbecausetrucksarrivinglatestages:selectingthetruckfromwhichtotakethesampletendtobepartiallyfull,especiallyifthefacilitychargesbyandcollectingthesamplefromtheloaddischargedfromthetonratherthanbythecubicyard.theselectedtruck.Obtainingsamplesastheyareneededforsortingissim-ilartocollectingasampleeverynminutesandhasthesamedisadvantages.RegardlessofthesamplingprotocolSELECTINGSAMPLESused,however,thesortersshouldbekeptsuppliedwithEnvironmentalengineersusuallyselectindividualtrucksinwastetosorteveniftheavailableloadsdonotfitthepro-thefieldtosample,buttheycanselecttrucksinadvancetocol.Havingmoredataisbetter.©1999CRCPressLLC ASTMD5231specificallyidentifiestheuseofaran-anduncompactedwaste.Manyfacilitiesreceivelittleun-domnumbergeneratorasanacceptablemethodforran-compactedMSW,whileothersreceivesubstantialquanti-domselectionofvehiclestosample.Arandomnumberties.generatorcanproviderandomintervalscorrespondingtoBecausepercapitagenerationofhouseholdwasteisrel-eachofthepredeterminedintervalsjustdiscussed.Forex-ativelyconsistent,environmentalengineerscanusepopu-ample,ifafacilityreceives120trucksperdayand12arelationdatatoallocatesamplesofhouseholdwasteamongtobesampled,onecaneithersampleevery10thtruckormunicipalitiesifthenecessaryquantityrecordsarenotusetherandomnumbergeneratortogenerate12randomavailable.numbersfrom1to120.Similarly,randomintervalsofFieldpersonnelmustinterviewprivatehaulersarrivingwastetonnage,wastevolume,orelapsedtimecanbegen-atthesolidwastefacilitytolearntheoriginsoftheloaderated.ofwaste.Informationprovidedbythehaulersisoftenin-Randomsamplingintervalshavethesamedisadvan-complete.Insomecasesthisinformationcanbesupple-tagesasthecorrespondingconstantsamplingintervalsplusmentedorcorrectedduringsortingofthesample.thefollowingadditionaldisadvantages:McCamic(1985)providesadditionalinformation.Randomsamplingintervalsincreasetheprobabilitythatthefieldcrewisidlefromtimetotime.COLLECTINGSAMPLESRandomsamplingintervalsincreasetheprobabilitythatthefieldcrewhastoworkovertime.Mostprotocols,includingASTMD5231,statethateachRandomsamplingintervalsincreasetheprobabilitythatselectedtruckshouldbedirectedtodischargeitsloadintargetedtrucksaremissedwhentoomanyrandomlyanareadesignatedforsamplecollection.Thisprovisionisselectedtrucksarrivewithintooshortatimeperiod.convenientforsamplersbutisnotnecessaryifaquickandsimplesamplingmethodisused.ASTMD5231statesthatInmanycases,samplingbywastesourceminimizesthethesurfaceonwhichtheselectedloadisdischargedshouldproblemsassociatedwiththesetypesofintervalsampling.beclean,butinmoststudiespreventingasamplefromSourcesofwastefromwhichsamplescanbeselectedin-containingafewouncesofmaterialfromadifferentloadcludeindividualmunicipalities,individualwastehaulers,ofwasteisunnecessary.specificcollectionroutes,wastegenerationsectorssuchasUnderstandingtheissuesinvolvedinselectingasam-theresidentialsectorandthecommercialsector,andspe-plingmethodrequiresanappreciationofthenatureofacificsourcessuchasrestaurantsorapartmentbuildings.loadofMSWdischargedfromastandardcompactortruckIngeneral,samplingbysourcemakessenseifadequatein-ontothesurfaceofalandfillorapavedtippingfloor.formationisavailableonthequantityofwastefromeachRatherthancollapsingintoaloosepile,thewastetendssourcetobesampled.Samplescanbecollectedfromeachtoretaintheshapeithadinthetruck.Thedischargedloadsourceinproportiontothequantityofwastefromeachcanbe7or8fthigh.Inmanyloads,thetrashbagsaresource,orthecompositionresultsforthevarioussourcespressedtogethersotightlythatpullingmaterialforthecanbeweightedbasedonthequantityfromeachsource.sampleoutoftheloadisdifficult.SomewasteusuallyfallsInthebestcase,thesolidwastefacilityhasascaleandoffthetoporsidesoftheload,butthisloosewasteshouldmaintainsacomputerdatabasecontainingthefollowingnotbeusedasthesamplebecauseitcanhaveunrepre-informationforeachloadofwaste:netweight,typeofsentativecharacteristics.waste,typeofvehicle,municipalityoforigin,hauler,andIngeneral,onesampleshouldberandomlyselectedanumberidentifyingtheindividualtruckthatdeliveredfromeachselectedtruck,asspecifiedinASTMD5231.Ifthewaste.Thisinformation,combinedwithinformationmorethanonesamplemustbetakenfromoneload,theonthehaulingcontractsineffectineachmunicipality,issamplesshouldbecollectedfromdifferentpartsoftheusuallysufficienttoestimatethequantityofhouseholdandload.commercialMSWfromeachmunicipality.AthresholdquestionisthesizeofthesamplecollectedThemunicipalityisoftenthehaulerforhouseholdfromeachtruck.Varioussamplesizeshavebeenused,waste,and,inthosemunicipalities,privatehaulersusuallyrangingfrom50lbtotheentireload.Largesampleshavehandlecommercialwaste.Inothercases,themunicipalitythefollowingadvantages:hasacontractwithaprivatehaulertocollecthouseholdwasteanddiscouragesthehaulerfromusingthesameve-Thevariation(standarddeviation)betweensamplesishiclestoserviceprivateaccounts.Householdandcom-smaller,sofewersamplesarerequiredtoachieveagivenmercialwastecanalsobedistinguishedbythetypesofve-levelofprecision.hiclesinwhichtheyaredelivered.DominantvehicletypesThedistributionoftheresultsofsortingthesamplesisvaryfromoneregiontoanother.closertoanormaldistribution(bell-shapedcurve).Ifthesolidwastefacilityhasnoscale,environmentalTheboundaryareabetweenthesampleandtheremain-engineerscanuserecordsofwastevolumesindesigningaderoftheloadissmallerinproportiontothevolumesamplingplanbutmustdifferentiatebetweencompactedofthesample,makingthesampler’sdecisionson©1999CRCPressLLC whethertoincludebulkyitemsfromtheboundaryareaConingandquarteringhasthefollowingdisadvantageslesssignificant.andpotentialdifficultiescomparedtograbsamplingorcolumnsampling:Smallsampleshaveasingleadvantage:shortercollec-tionandsortingtime.SubstantiallyincreasessamplingtimeAconsensushasdeveloped(SCSEngineers1979;KleeRequiresmorespaceandCarruth1970;Britton1971)thattheoptimumsam-Requirestheuseofafront-endloaderforrelativelylongplesizeis200to300lb(91to136kg).Thissizerangeisperiods.Manysolidwastefacilitiescanmakeafront-recommendedinASTMD5231.Theadvantagesofin-endloaderandanoperatoravailableforbriefperiods,creasingthesamplesizebeyondthisrangedonotoutweighbutsomecannotprovideafront-endloaderforthethereducednumberofsamplesthatcanbesorted.Ifthelongerperiodsrequiredforconingandquartering.samplesizeislessthan200lb,theboundaryareaaroundTendstobreaktrashbags,makingthewastemorediffi-thesampleistoolargecomparedtothevolumeofthesam-culttohandleple,andthesamplermustmaketoomanydecisionsaboutIncreasessortingtimebybreakingupclustersofacate-whethertoincludeboundaryitemsinthesample.goryofwasteEnvironmentalengineersuseseveralgeneralproceduresReducesaccuracyofsortingbyincreasingthepercentagetoobtainsamplesof200to300lbfromloadsofMSW,offoodwasteadheringtoorabsorbedintootherwasteincludingthefollowing:itemsPromoteslossofmoisturefromthesampleAssemblingacompositesamplefrommaterialtakenfromPromotesstratificationofthewastebydensityandparti-predeterminedpointsintheload(suchaseachcornerclesize.Thebiasingpotentialofstratificationismini-andthemiddleofeachside)mizedifthequarterusedasthesampleisatruepieConingandquarteringslice,withitssidesverticalanditspointatthecenterCollectingagrabsamplefromarandomlyselectedpointofthecone.Thisshapeisdifficulttoachieveinprac-usingafront-endloadertice.ManuallycollectingacolumnofwastefromarandomlyselectedlocationTheadvantageofconingandquarteringisthatitre-ducesthevariation(thestandarddeviation)amongtheNumerousvariationsandcombinationsofthesegen-samples,therebyreducingthenumberofsamplesthatmusteralprocedurescanalsobeused.besorted.ConingandquarteringisjustifiedifitreducesTheprimarydisadvantageofcompositesamplesisthethestandarddeviationenoughtomakeupforthedisad-sameasthatforsmallsamples:thelargeboundaryareavantagesandpotentialdifficulties.Ifconingandquarter-forcesthesamplertomaketoomanydecisionsaboutingisdoneperfectlyandcompletely,sortingthefinalsam-whethertoincludeitemsofwasteinthesample.Acom-pleisequivalenttosortingtheentireconeofwaste,andpositesampletendstobeajudgementsampleratherthanthestandarddeviationissignificantlyreduced.Sincethearandomsample.Asecondarydisadvantageofcompos-numberofsamplesthatmustbesortedtoachieveagivenitesamplesisthattheytakelongertocollectthangrablevelofprecisionisproportionaltothesquareofthestan-samplesorcolumnsamples.darddeviation,coningandquarteringcansubstantiallyre-Avariationofcompositesamplingistoassembleeachducetherequirednumberofsamples.Note,however,thatsamplefrommaterialfromdifferentloadsofwaste.Thisthemorethoroughlyconingandquarteringisperformed,approachhasthesamedisadvantagesascompositesam-themorepronouncedareeachofthedisadvantagesandplingfromasingleloadofwasteandisevenmoretime-potentialdifficultiesassociatedwiththismethod.consuming.Amorecommonmethodofsolidwastesamplingiscol-Inconingandquartering,samplersmixalargequan-lectingagrabsampleusingafront-endloader.Thismethodtityofwastetomakeitscharacteristicsmoreuniform,isrelativelyquickandcanoftenbedonebyfacilityper-arrangethemixedwasteinaroundpile(coning),andran-sonnelwithoutundulydisruptingnormalfacilityopera-domlyselectaportion—typicallyonequarter—ofthetions.Samplingbyfront-endloaderreducesthepotentialmixedwaste(quartering).Thepurposeistocombinetheimpactofthepersonalbiasesassociatedwithmanualsam-statisticaladvantagesoflargesampleswiththereducedplingmethodsbutintroducesthepotentialforothertypessortingtimeofsmallersamples.Theconingandquarter-ofbias,includingthefollowing:ingprocesscanbeginwiththeentireloadofwasteorwithaportionoftheloadandcanbeperformedonceormul-Likeshovelsampling,front-endloadersamplingtendstotipletimestoobtainasinglesample.ASTMD5231spec-favorsmallanddenseobjectsoverlargeandlightob-ifiesoneroundofconingandquartering,beginningwithjects.Largeandlightobjectstendtobepushedawayapproximately1000lbofwaste,toobtainasampleofortofallawayasthefront-endloaderbucketisin-200to300lb.serted,lifted,orwithdrawn.©1999CRCPressLLC Ontheotherhand,thebreakingoftrashbagsasthefront-broadlyrepresentativeoftheloadbuthasthedisadvan-endloaderbucketpenetratestheloadofwastetendstotageofincreasingsamplingtime.releasedense,finematerialfromthebags,reducingtheInasecondhybridsamplingprocedure,afront-endrepresentationofthismaterialinthesample.loaderloosensasmallquantityofwastefromarandomlyFront-endloadersamplestakenatgroundlevelfavorwasteselectedpointorcolumnontheload,andthesampleisthatfallsoffthetopandsidesoftheload,whichmaycollectedmanuallyfromtheloosenedwaste.Thismethodnothavethesamecharacteristicsaswastethatstaysinissaferthanmanualcolumnsamplingandprovidesmoreplace.Ondirtsurfaces,front-endloadersamplestakencontrolovertheweightofthesamplethansamplingbyatgroundlevelcanbecontaminatedwithdirt.front-endloader.Thismethodlargelyavoidsthepotentialbiasesoffront-endloadersamplingbuttendstointroduceTheimpactofthesebiasingfactorscanbereducedifthepersonalbiasesofthesampler.thesamplingisdonecarefullyandthesamplingpersonnelcorrectclearsourcesofbias,suchasbulkyobjectsfallingoffthebucketasitislifted.NumberofSamplesRequiredtoInfront-endloadersampling,samplingpersonnelcanEstimateCompositionusedifferentsamplingpointsfordifferentloadstoensurethatthevarioushorizontalandverticalstrataoftheloadsThenumberofsamplesrequiredtoachieveagivenlevelarerepresentedinthesamples.Theycanvarythesamplingofstatisticalconfidenceintheoverallresultsisafunctionpointeitherrandomlyorinarepeatingpattern.Theex-ofthevariationamongtheresultsforindividualsamplestentofthebiasthatcouldresultfromusingthesamesam-(standarddeviation)andthepatternofthedistributionofplingpointforeachloadisnotknown.theresults.Neitherofthesefactorscanbeknowninad-Aninherentdisadvantageoffront-endloadersamplingvance,butbothcanbeestimatedbasedontheresultsofisthedifficultyinestimatingtheweightofthesamples.otherstudies.Weightcanonlybeestimatedbasedonvolume,andsam-ASTMD5231prescribesthefollowingequationfromplesofequalvolumehavedifferentweights.classicalstatisticstoestimatethenumberofsamplesre-Alesscommonmethodofsolidwastesamplingisman-quired:uallycollectinganarrowcolumnofwastefromaran-n5(t*s/ex)210.4(4)domlyselectedlocationonthesurfaceoftheload,ex-where:tendingfromthebottomtothetopoftheload.Thismethodhasthefollowingadvantages:n5requirednumberofsamplest*5studenttstatisticcorrespondingtothelevelofcon-•Noheavyequipmentisrequired.fidenceandapreliminaryestimateoftherequired•Samplingtimeisrelativelyshort.numberofsampless5estimatedstandarddeviation•Becausedifferenthorizontalstrataoftheloadaree5levelofprecisionsampled,thesamplesmorebroadlyrepresentthex5estimatedmeanloadthangrabsamplescollectedusingafront-endloader.Note,however,thatloadsarealsostrati-Table10.4.1showsrepresentativevaluesofthecoeffi-fiedfromfronttoback,andcolumnsamplesdocientofvariationandmeanforvarioussolidwastecom-notrepresentdifferentverticalstrata.ponents.Thecoefficientofvariationistheratioofthestan-•Thenarrownessofthetargetareawithintheloaddarddeviationtothemean,somultiplyingthemeanbyminimizesthediscretionofthesamplerinchoos-thecoefficientofvariationcalculatesthestandarddevia-ingwastetoincludeinthesample.tion.Table10.4.2showsvaluesofthestudenttstatistic.Table10.4.1showsthecoefficientsofvariationratherThemajordisadvantageofcolumnsamplingisthatthanstandarddeviationsbecausethestandarddeviationmanualextractionofwastefromthesideofawell-com-tendstoincreaseasthemeanincreases,whilethecoeffi-pactedloadisdifficult,andtheriskofcutsandpuncturecientofvariationtendstoremainrelativelyconstant.woundsfrompullingonthewasteissubstantial.Therefore,thestandarddeviationsforsetsofmeansdif-Ofthemanyhybridsamplingproceduresthatcombineferentfromthoseinthetablecanbeestimatedfromthefeaturesofthesefourgeneralprocedures,twoareworthycoefficientsofvariationinthetable.ofparticularnote.First,inthesamplingprocedurespeci-TheconfidencelevelisthestatisticalprobabilitythatfiedinASTMD5231,afront-endloaderremovesatleastthetruemeanfallswithinagivenintervalaboveandbe-1000lb(454kg)ofmaterialalongoneentiresideofthelowthemean,withthemeanasthemidpoint(theconfi-load;andthiswasteismixed,coned,andquarteredtodenceintervalorconfidencerange).Aconfidencelevelofyieldasampleof200to300lb(91to136kg).Compared90%isgenerallyusedinsolidwastestudies.Theconfi-tograbsamplingusingafront-endloader,theASTMdenceintervaliscalculatedbasedontheresultsofthestudymethodhastheadvantageofgeneratingsamplesmore(seeTable10.4.3laterinthissection).©1999CRCPressLLC TABLE10.4.1REPRESENTATIVEMEANSANDTABLE10.4.2VALUESOFSTUDENTtSTATISTICCOEFFICIENTSOFVARIATIONFORMSWCOMPONENTSStudenttStatisticNumberofSamples(n)90%Confidence95%ConfidenceCoefficientofMeanVariationa0026.31412.706WasteCategory(%)(%)0032.9204.3030042.3533.182Organics/Combustibles86.6100052.1322.776Paper39.8300062.0152.571Newspaper6.8800071.9432.447Corrugated8.6950081.8952.365Kraft1.51200091.8602.306Corrugated&kraft10.185b0101.8332.262Otherpaper22.9400121.7962.201High-gradepaper1.7230b0141.7712.160Otherpaper21.2400171.7462.120Magazines2.1160b0201.7292.093Otherpaper19.1400251.7112.064Officepaper3.4—0301.6992.045Magazines&mail4.090b0411.6842.021Otherpaper17.2400511.6762.009Yardwaste9.71600611.6712.000Grassclippings4.03000811.6641.990Otheryardwaste5.71801011.6601.984Foodwaste12.0701411.6561.977Plastic9.4402011.6531.972PETbottles0.40100Infinity1.6451.960HDPEbottles0.7095Otherplastic8.350Polystyrene1.095PVCbottles0.06200Thedesiredlevelofprecisionisthemaximumaccept-bOtherplastic7.250ableerror,expressedasapercentageordecimalfractionPolyethylenebags&film3.745oftheestimatedmean.NotethatalowerprecisionlevelbOtherplastic3.580indicatesgreaterprecision.Aprecisionlevelof10%(0.1)Otherorganics15.755isfrequentlysetasagoalbutisseldomachieved.Wood4.0170AfterapreliminaryvaluefornbasedonapreliminaryTextiles3.5—Textiles/rubber/leather4.5110valuefort*iscalculated,thecalculationisrepeatedwithFines3.370thevalueoft*correspondingtothepreliminaryvalueforFines,Asinch2.280n.Disposablediapers2.5110Equation10.4(4)assumesthatthevaluesforeachvari-Otherorganics1.4160abletobemeasured(inthiscasethepercentagesofeachInorganics/Noncombustibles13.460solidwastecomponentinthedifferentsamples)arenor-Metal5.870mallydistributed(conformtothefamiliarbell-shapeddis-Aluminum1.070tributioncurve,withthemostfrequentvalueequalingtheAluminumcans0.695mean).Inreality,solidwastecompositiondataarenotOtheraluminum0.4120normallydistributedbutaremoderatelytoseverelyskewedTin&bimetalcans1.570bright,withnumerousvaluesseveraltimeshigherthantheOthermetal3.3130Ferrousmetal4.585mean.ThemostfrequentvalueisinvariablylowerthanGlass4.870themean,andinsomecasesisclosetozero.ThegreaterFood&beveragecontainers4.385thenumberofwastecategories,themoreskewedthedis-Batteries0.1160tributionsofindividualcategoriesare.OtherinorganicsKlee(1991;1993)andKleeandCarruth(1970)haveWithnoncontainerglass3.2160suggestedequationstoaccountfortheeffectofthisskew-Withoutnoncontainerglass2.7200nessphenomenonontherequirednumberofsamples.UseaStandarddeviationdividedbythemean,basedonsamplesof200to300oftheseequationsisproblematic.LikeEquation10.4(4),pounds.theyaredesignedforusewithonewastecategoryatabEach“other”categorycontainsallmaterialoftheprevioustypeexceptma-time.Forwastecategoriesforwhichthemeanislargecom-terialinthosecategories.paredtothestandarddeviation,theequationsyieldhigher©1999CRCPressLLC numbersofsamplesthanEquation10.4(4).Thisresultistheindividualwastecategories.Theprecisionlevelforin-intuitivelysatisfyingbecausemoredatashouldbeneededdividualwastecategoriescanbeestimatedwiththefol-toquantifyaparameterwhosevaluesdonotfollowapre-lowingequation,whichisEquation10.4(4)solvedfore:defined,normalpatternofdistribution.Forwastecate-1/2e5t*s/xn10.4(5)goriesforwhichthemeanislessthantwiceaslargeasthestandarddeviation,however,theseequationstendtoyieldTheprecisionlevelforeachcategoryismultipliedbynumbersofsamplessmallerthanEquation10.4(4).Thisthemeanforthatcategory,andtheresultsaretotaledtoresultiscounterintuitivesincenoreasonisapparentforyieldtheweighted-averageprecisionlevel.Thenumberofwhyanassumptionofnonnormaldistributionshouldde-samples(n)isadjustedbytrialanderroruntiltheweighted-creasethequantityofdatarequiredtocharacterizeahighlyaverageprecisionlevelmatchestherequiredvalue.variableparameter.Calculationoftheweighted-averageprecisionlevelisAnalternativemethodofaccountingforskewnessistoshowninTable10.4.3laterinthissection.Figure10.4.1selectordevelopanappropriateequationforeachwasteshowstherelationshipoftheweighted-averageprecisioncategorybasedonanalysisofexistingdataforthatcate-leveltothenumberofsamplesandthenumberofwastegory.Hilton,Rigo,andChandler(1992)providethere-categoriesbasedonthevaluesinTable10.4.1.Overallsultsofastatisticalanalysisoftheskewnessofindividualprecisionimprovesasthenumberofsamplesincreasesandwastecategories.asthenumberofwastecategoriesdecreases.Thisstate-Equation10.4(4)givesdivergentresultsfordifferentmentdoesnotmeanthatstudiesinvolvinggreaternum-solidwastecomponents.Basedonthecomponentmeansberofcategoriesareinferior;itsimplymeansthatdeter-andcoefficientsofvariationshowninTable10.4.1andminingafewthingspreciselyiseasierthandeterminingassumingaprecisionof10%at90%confidence,thenum-manythingsprecisely.berofsamplesgivenbyEquation10.4(4)is45forpaperotherthancorrugated,kraft,andhigh-grade;almost700SortingandWeighingSamplesofforallyardwaste;andmorethan2400forjustgrassclip-MSWpings.ThevalueofEquation10.4(4)aloneasaguideindesigningasamplingprogramisthereforelimited.Inmostcases,sortingsolidwasteshouldbeviewedasanAnalternativemethodistoestimatethenumberofsam-industrialoperation,notaslaboratoryresearch.Whileac-plesrequiredtoachieveaweighted-averageprecisionlevelcuracyisessential,theappropriatemeasureofaccuracyisequaltotherequiredlevelofprecision.Theweighted-av-ouncesratherthangramsormilligrams.Insistenceonanerageprecisionlevelistheaverageoftheprecisionlevelsexcessivelevelofaccuracyslowsdownthesortingprocess,forindividualwastecategoriesweightedbythemeansforreducingthenumberofsamplesthatcanbesorted.This60%50%40%30%20%Weighted-AveragePrecisionLevel10%0%1030507090110130150170190210230250270290310330350NumberofSamples(200to300lb)Key:2Categories8Categories18Categories27CategoriesFIG.10.4.1Effectofthenumberofsamplesandthenumberofwastecategoriesonweighted-averageprecisionlevel(derivedfromTable10.4.1).©1999CRCPressLLC reduction,inturn,reducesthestatisticalprecisionoftheSORTINGCONTAINERSresults.Inthecontextofanoperationinwhicha10%Useofacounter-heightsortingboxspeedssorting,de-precisionlevelisatypicalgoal,inaccuracyof1%isrela-creasesworkerfatigue,andencouragesinteractionamongtivelyunimportant.thesorters.AllofthesefactorshelpbuildandsustaintheTheprinciplesofindustrialoperationsapplytosolidmoraleofthesorters.wastesorting,includingminimizationofmotionandmain-Thefollowingsortingboxdesignhasprovenhighlyef-tenanceofworkercomfortandmorale.fective.Theboxis4ftwide,6ftlong,1ftdeep,andopenatthetop.Itisconstructedof3/8-inor1/2-inplywoodwithaninternalframeof2-by-3sor2-by-4s.ThelongSORTINGAREASframingpiecesextend1footbeyondtheendsoftheboxAsortingareaisestablishedatthebeginningofthefieldateachbottomcorner,likethepolesofastretcher.Theseworkandshouldhavethefollowingcharacteristics:framingpiecesfacilitatehandlingandextendtheoveralldimensionsoftheboxto4ftby8ftby1ft.Theboxcan•Apavedsurfaceapproximately1000sqftinarealieflatwithinthebedofafull-sizedpickuptruckorstan-andatleast16ftwidedardcargovan.•AccessibilitytovehiclesAscreenof1/2-inhardwarecloth(wiremeshwithAs-•Protectionfromprecipitationandstrongwindsinsquareopenings)canbemountedinthebottomofthe•Heatingincoldweathersortingbox,11/2infromthebottom(thethicknessofthe•Separationfromtrafficlanesandareaswhereheavyequipmentisusedbutwithinsightofar-internalframingpieces).Ifthescreenisincluded,oneendrivingtrucksoftheboxmustbeopenbelowthelevelofthescreentoallowdumpingofthefinematerialthatfallsthroughtheAtypicalsortingoperationmightusetwosortingboxesscreen.Byallowingfinematerialtoseparatefromtherestandacrewoftentotwelve.Thecrewincludestwosort-ofthesample,thescreenfacilitatessortingofsmallitemsingteamsoffourorfivepersonseach,asupervisor,andandmakesdangerousitemssuchashypodermicneedlesautilityworker.Thebasicsortingsequence,startingwheneasiertospot.collectionofthesampleiscomplete,isasfollows:Tofacilitatedumpingofthefinesandtosavespacedur-ingtransportationandstorage,thesortingboxisbuilt1.Thesampleistransportedfromthesamplingpointtowithoutlegs.Duringsorting,thesortingboxisplacedonthesortingarea.Apickuptruckorfront-endloaderapairofheavy-dutysawhorses,55-galdrums,orothercanbeusedforthispurpose.supports.Asupportheightof32inworkswellforamixed2.Thesamplergivesthesortingsupervisoracopyofagroupofmaleandfemalesorters.Fifty-five-galdrumsaredataform.approximately35inhigh,approximately3inhigherthan3.Thesampleisunloadedontothesurfaceofthesort-optimum,andbecauseoftheirsizeareinconvenienttoingarea.storeandtransport.4.Largeitems(e.g.,corrugatedcardboardandwood)Thecontainersintowhichthewasteissortedshouldandbagscontainingasinglewastecategory(mostof-beacombinationof30-galplastictrashcontainersandtenyardwaste)areremovedfromthesampleandset5-galplasticbuckets.The5-galbucketsareusedforlow-asideforweighing,bypassingthesortingbox.volumewastecategories.Containerslargerthan30galoc-5.Theremainderofthesampleistransferredbyincre-cupytoomuchspacearoundthesortingboxforefficientmentsintothesortingbox,usingbroad-bladedshov-sortingandcanbeheavywhenfull.Inatypicalstudywithelstotransferloosematerial.6.Thewasteissortedintothecontainerssurroundingtwenty-fourtotwenty-eightwastecategories,eachsortingthesortingbox.crewshouldbeequippedwithapproximatelytwodozen7.Thecontainersarebroughttothescale,checkedfor30-galcontainersandonedozen5-galbuckets.Inaddi-accuracyofsorting,andweighed.tion,eachsortingcrewshouldhaveseveralshallowplas-8.Thegrossweightofthewasteandcontainerandalet-ticcontainersapproximately18inwide,24inlong,andtersymbolindicatingthetypeofcontainerare6indeep.recordedonthedataform.Foroptimumuseofspace,the30-galcontainersshould9.Ifrequired,thewasteinthecontainersissubsampledhaverectangularrims.Theyshouldalsohavelargehan-forlaboratoryanalysis.dlestofacilitatedumping.Recessedhandholdsinthebot-10.Thecontainersaredumpedinadesignatedreceptacletomofthecontainerarealsohelpful.Ingeneral,contain-orlocation.ersofheavy-dutyHDPEarebest.Becauseoftheirmoldedrims,thesecontainerscanbeinvertedandbangedagainstThesupervisormustensurethateachsampleremainspavement,therimofarolloffcontainer,ortherimofamatchedwiththecorrectdataformandthatwastedoesmatchingcontainertodislodgethematerialadheringtonotcrossbetweensamples.theinsideofthecontainer.Thecontainersneednothave©1999CRCPressLLC wheels.PlasticcontainersslideeasilyacrossalmostanyflatSORTINGPROCESSsurface.TheactualsortingofthesampleshouldbeorganizedinSubstantialfieldtimecanbesavedwhenthecontain-thefollowingbasicmanner:ersofeachtypehavefairlyuniformweightssothateachtypeofcontainercanbeassignedatareweightratherthanEachwastecategoryisassignedagenerallocationaroundeachcontainer.Whencontainerweightsarerecordedontheperimeterofthesortingbox.Inoneeffectivethedataformaftersorting,recordingalettercodethatarrangement,papercategoriesaresortedtoonesideofreferstothetypeofcontainerisfasterthanreadinganin-thesortingbox,plasticcategoriesaresortedtotheotherdividualtareweightonthecontainerandrecordingitonside,otherorganiccategoriesaresortedtooneend,andthedataform.inorganiccategoriesaresortedtotheotherend.Assigningindividualtareweightstocontainersweigh-Eachsorterisassignedagroupofcategories.Withatyp-ing2%moreorlessthantheaverageweightforthecon-icalsortingcrewoffour,eachsorterisassignedthecat-tainertypeisunnecessary.Batchesof5-galbucketsgen-egoriesononesideoratoneendofthebox.erallymeetthisstandard,butmany30-galcontainersdoThesortersplacetheirassignedmaterialsintheappropri-not.Ensuringthattareweightsareconsistentrequiresatecontainersandplaceothermaterialswithinreachusingportablescalewhenshoppingforcontainers.ofthesorterstowhichtheyareassigned.Towardtheendofsortingeachsample,oneoftheshal-lowcontainersisplacedinthemiddleofthesortingCONTAINERLABELINGbox,andallsortersplaceotherpaperinthiscontainer(seeTable10.4.1).ThisprocesscanberepeatedforfoodMostsortingprotocols,includingASTMD5231,callforwaste.labelingeachcontainertoindicatewhichwastecategoryWhenonlyscatteredormixedbitsofwasteremain,sort-istobeplacedinit.Whenasortingboxisused,however,ingissuspended.unlabeledcontainershavethefollowingadvantages:ThematerialremainingabovethescreeninthesortingThesortersareencouragedtoestablishacustomaryloca-box,oronthebottomofaboxwithoutascreen,istionforeachwastecategoryandsortbylocation,whichscrapedorbrushedtogetherandeither(1)distributedisfasterthansortingbylabels.amongthecategoriesrepresentedinitinproportiontoWhensortingisdonebylocationratherthanbylabels,theirabundance,(2)setasideasaseparatecategory,orthecontainerscanbeplacedclosertothesorters,which(3)setasidetobecombinedwiththefinematerialfromfurtherspeedsthesortingprocess.belowthescreen.ASTMD5231specifiesthefirstal-Lesstimeisrequiredtoarrangeunlabeledcontainersternative,butitshouldnotbeselectedifthewastecat-aroundthesortingboxafterthesortedmaterialfromegoriesaretobesubsampledforlaboratorytesting.theprevioussamplehasbeenweighedanddumped.Ifthesortingboxhasascreen,theboxisupendedtoal-Keepingthecontainersunlabeledincreasestheflexibilitylowthefinematerialfrombelowthescreentofallofthesortingoperation.throughtheslotatoneendofthebox.Thematerialthatfallsoutisswepttogetherandshoveledintoacon-Theflexibilitygainedbynotlabelingthecontainershastainer—preferablyawide,shallowcontainer—forseveralaspects.First,differentsamplesrequiremultiple30-weighing.galcontainersfordifferentwastecategories.Second,manywastecategoriesrequirea30-galcontainerforsomesam-WEIGHINGSAMPLESplesandonlya5-galcontainerforothers.Third,theneedforanotheremptycontainerarisesfrequentlyinanactiveASTMD5231specifiestheuseofamechanicalorelec-sortingoperation,andgrabbingthenearestemptycon-tronicscalewithacapacityofatleast200lb(91kg)andtainerisquickerthansearchingforthecontainerwiththeprecisionof0.1lb(0.045kg)orbetter.When30-galcon-appropriatelabel.tainersareusedinsortingsamplesof200to300lb,grossDespitetheadvantagesofunlabeledcontainers,thecon-weightsgreaterthan100lbareunusual.Eveniflargercon-tainersforfoodwasteshouldbelabeled.Ifindividualcon-tainersorsamplesizesareused,sortingpersonnelshouldtainersarenotdesignatedforfoodwaste,allcontainersavoidcreatingcontainerswithgrossweightsgreaterthanwilleventuallybecoatedwithfoodresidue.Thisresidue100lbbecausetheyaredifficultanddangeroustohandle.isunpleasantandchangesthetareweightsofthecon-Formostsortingoperations,ascalecapacityof100lbistainers.adequate.Anelectronicscalewitharangeof0–100lbisThetareweightsofthefoodwastecontainersshouldgenerallyeasiertoreadtowithin0.1lbthanamechani-becheckeddaily.Generally,checkingthetareweightsofcalscalewitharangeof0–100lb.othercontainersatthebeginningofeachweekoffieldAplatform-typescaleispreferred.Theplatformshouldworkissufficientunlessavisiblebuildupofresidueindi-be1ftsquareorlarger.catesthatmorefrequentcheckingisrequired.©1999CRCPressLLC Thedigitaldisplaysonelectronicscalesmakedata•Thepercentagebyweightineachsamplerecordingeasierandminimizerecordingerrorsbydis-•Themeanpercentagewithinthegroupofsamplesplayingtheactualnumbertoberecordedonthedataform.•ThestandarddeviationofthepercentageswithinWhenrecordingweightsfromamechanicalscale,inter-thegroupofsamplespolationbetweentwovaluesmarkedonthedialisoften•Theconfidenceintervalaroundthemeanrequired.TheadvantagesofmechanicalscalesarelowerCalculatingtheoverallcompositionusuallyinvolvesdi-cost,reliability,anddurability.vidingthetotalweightofeachwastecategorybytheto-Ideally,oneworkerplacescontainersonthescale,thetalweightofthesamplesratherthancalculatingthecom-supervisorchecksthecontainersforaccuracyofsortingpositionofeachsampleandaveragingthecompositions.andrecordstheweightsandcontainertypes,andtwoorIfthesampleshavedifferentweights,whichisusuallythemoreworkersdumptheweighedcontainers.Ifthecon-case,thesetwomethodsyielddifferentresults.Calculatingtainersaresubsampledforlaboratoryanalysispriortobe-overallcompositionbasedontotalweightcreatesabiasingdumped,theprocessismuchslowerandfewerwork-infavorofdensematerials,whicharemoreabundantinersarerequired.theheaviersamples.Averagingthecompositionsofthein-dividualsamplesispreferablebecauseitgiveseachpoundDUMPINGSAMPLESofwasteanequalopportunitytoinfluencetheresults.ASTMD5231specifiesaveragingofsamplecompositions.Onlandfills,thesortingcontainersaredumpedneartheTable10.4.3showsmeanpercentages,standarddevia-sortingareaforremovalorin-placeburialbyfacilityper-tions,uncertaintyvalues,precisionlevels,andconfidencesonnel.Intransferstationsandwaste-to-energyfacilities,intervalsforagroupof200MSWsampleswiththechar-thecontainerscanbedumpedontheedgeofthetippingacteristicsshowninTable10.4.1.Theconfidenceintervalsfloor.arebasedontheuncertaintyvalues(sometimescalledpre-Whenthesortingareaisseparatedfromthedisposalcisionvalues).Theuncertaintyvaluesaretypicallycalcu-area,useofthesamplingvehiclefordisposalisdifficult.latedwiththefollowingformula:Loadsofwastethatshouldbesampledcanbemissed,and1/2sortingdelaysoccurbecausethesamplingvehicleisnotUc5t*s/n10.4(6)availablefordumpingfullcontainersfromthepreviouswhere:sample.Abetterprocedureistodumpthesortedwasteinarolloffcontainerprovidedbythedisposalfacility.FacilityUc5uncertaintyvalueatagivenlevelofconfidence,personneltransporttherolloffcontainertothedisposaltypically90%areaapproximatelyonceperday.Thedensityofsortedt*5studenttstatisticcorrespondingtothegivenlevelofconfidencewasteisoftenaslowas150lb/cuyd,sotherollofftendss5samplestandarddeviationtobefilledmorerapidlythanexpected.Tofacilitatedump-n5numberofsamplesingsortedwasteoverthesides,therolloffcontainershouldnotbelargerthan20cuyd(15.3cum).Thisequationisequivalenttotheequationforcalcu-latingtheprecisionlevel,Equation10.4(5),withbothsidesmultipliedbythemean,x.DividingtheuncertaintyvalueProcessingtheResultsofSortingbythemeanyieldstheprecisionlevel.Addingtheuncer-Afterasampleisweighedandthegrossweightsandcon-taintyvaluesforallwastecategoriesyieldstheweightedtainertypesarerecordedonthedataform,thenetweightsaverageprecisionlevel,weightedbythemeansforthein-arecalculatedandrecordedonthedataform.Totalnetdividualwastecategories.weightsarecalculatedforwastecategoriessortedintoEquation10.4(6),likeEquations10.4(4)and10.4(5),morethanonecontainer.Fieldpersonnelshouldcalculateassumesthatthepercentagedataarenormallydistributed.netcategoryweightsandtotalnetsampleweightsafterAspreviouslydiscussed,thisisnotactuallythecase,andeachdayofsortingtomonitorthesizeofthesamples.noreliableandreasonablysimplemethodexistsforesti-Undersizesamplesdecreasetheaccuracyandstatisticalpre-matingtheeffectoflackofnormalityonthestatisticalpre-cisionoftheresultsandcanviolatethecontractundercisionoftheresults.whichthestudyisconducted.Oversizesamplesmakesort-Precisionanalysiscanonlybeappliedtogroupsofsam-ingtherequirednumberofsamplesmoredifficult.plesthatarerepresentativeofthewastestreamtobean-Thenetweightsforeachwastecategoryineachsam-alyzed.Forexample,if40%ofthemunicipalwastestreampleareusuallyenteredintoacomputerspreadsheet.Foriscommercialwastebut60%ofthesamplessorteddur-eachwastecategoryineachgroupofsamplestobeana-ingastudyarecollectedfromcommercialloads,statisti-lyzed(forexample,residentialsamplesandcommercialcalprecisionanalysisoftheentirebodyofcompositionsamples),thefollowingshouldbecalculatedfromthedatadatageneratedduringthestudyismeaningless.Assuminginthespreadsheet:thatthecommercialandresidentialsamplesrepresentthe©1999CRCPressLLC aTABLE10.4.3ILLUSTRATIONOFWEIGHTED-AVERAGEPRECISIONLEVELANDCONFIDENCEINTERVALSStudenttStatistic(t*)forStandard200Samples(n)UncertaintyPrecision90%Mean(%)Deviation(%)and90%Value(%)Level(%)Confidence1/2WasteCategory(x)(s)Confidence(U905t*s/n)(U90/x)Interval(%)Newspaper6.85.41.6530.69.46.860.6Corrugated&kraft10.18.61.6531.09.910.161.0Otherpaper22.99.21.6531.14.722.961.1Yardwaste9.715.51.6531.818.79.761.8Foodwaste12.08.41.6531.08.212.061.0PETbottles0.40.41.6530.0511.70.460.05HDPEbottles0.70.71.6530.111.10.760.1Otherplastic8.34.11.6530.55.88.360.5Wood4.06.81.6530.819.94.060.8Textiles/rubber/leather4.55.01.6530.612.94.560.6Fines3.32.31.6530.38.23.360.3Disposablediapers2.52.81.6530.312.92.560.3Otherorganics1.42.21.6530.318.71.460.3Aluminum1.00.71.6530.18.21.060.1Tin&bimetalcans1.51.11.6530.18.21.560.1Othermetal3.34.31.6530.515.23.360.5Food&beveragecontainers4.33.71.6530.49.94.360.4Otherinorganics3.35.31.6530.618.73.360.6Totalorweightedaverage100.010.110.1100.0610.1aBasedon200samples,90%confidence,andtheeighteenwastecategorieslistedinthetable.MeansandstandarddeviationsarebasedonTable10.4.1.respectivefractionsofthewastestreamfromwhichtheyandastheheavyequipmentoperatorsmovetheloadwerecollected,separateprecisionanalysisofthecommer-aroundthetippingfloorortheworkingfaceoftheland-cialandresidentialresultsisvalid.Representativenessisfill.Second,theydetermineorestimatetheweightofeachachievedbyeitherrandomselectionofloadstosampleorload.Third,theycombinethefieldnotesandloadweightssystematicselectionofloadsbasedonpreexistingdata.todevelopanestimateofthecompositionofeachloadandofthebulkywasteasawhole.Ingeneral,thefieldnotesshouldincludethefollowingVisualCharacterizationofBulkyelementsforeachload:WasteThedateandexacttimeofdayThecompositionofbulkywasteistypicallyestimatedbyThetypeofvehicleanditsvolumetriccapacity(e.g.,30-observationratherthanbysortingsamples.Visualchar-cu-ydrolloff,40-cu-ydtrailer)acterizationofbulkywasteisfeasibleforseveralreasons:Anyidentifyingmarkingsthathelpmatchthefieldnotes(1)mostbulkywasteisnothiddeninbags,(2)mostloadswiththecorrespondingentryinthefacilitylogforthatofbulkywastecontainfewcategoriesofwaste,and(3)day.Identifyingmarkingsthatcanbeusefulincludethethecategoriesofwastepresentareusuallynotthoroughlynameofthehauler,thelicenseplatenumber,andiden-dispersedwithintheload,astheyareinloadsofMSW.tifyingnumbersissuedbyregulatoryagencies.Conversely,sortingsamplesofbulkywasteisproblematicEither(1)adirectestimateoftheby-weightcompositionforseveralreasons:(1)becausethevariationamongloadsoftheloador(2)anestimateoftheby-volumecom-ofbulkywasteislarge,alargenumberoftrucksmustbepositionoftheloadcombinedwithanindicationofthesampled,(2)becausethewastecategoriesarenotthor-amountofairspaceineachcomponent.oughlydispersedwithintheloads,thesamplesmustbelarge,(3)sortingandweighingbulkywasteisdifficultandIfthefacilitydoesnothaveascale,thefacilityloggen-dangerousifnotdonewithspecializedmechanicalequip-erallycontainsavolumeforeachloadbutnoweight.Ifment.thevolumeofeachloadcanbedeterminedinthefield,asEstimatingthecompositionofbulkywastebasedonitcanwheneachtruckorcontainerismarkedwithitsvol-observationhasthreephases.First,fieldpersonnelprepareumetriccapacity,fieldnotesdonothavetobematchedfieldnotesdescribingeachloadastheloadisdumped,aswithlogentries.Regardlessofwhetherthefacilitylogistheloadsitsonthetippingfloororlandfillafterdumping,used,thefieldnotesshouldcontainanyinformationthat©1999CRCPressLLC canbehelpfulinestimatingtheweightofeachload,in-ThecostofastudycanbereducedifthesamepersoncludingitstotalvolumeifdifferentfromthecapacityofcollectsMSWsamplesforsortingandperformsvisualthevehicleinwhichitarrived.characterizationofbulkywasteduringthesameperiodofFieldpersonnelshouldvisuallycharacterizemostifnotfieldwork.ThistechniqueisfeasibleifloadsofMSWandalloftheloadsofbulkywastearrivingatthesolidwastebulkywastearedumpedinthesamepartofthefacilityfacilityduringtheperiodoffieldwork.Becausethecom-andifaquickmethodisusedforcollectingMSWsam-positionofbulkywastevariesfromloadtoload,alargeples.numberofloadsmustbecharacterized.Characterizedloadsofbulkywasteshouldnotbere-gardedassamplesbecausetheycontainvastlydifferentSamplingMSWforLaboratoryquantitiesofwaste.TheoverallcompositionofbulkyAnalysiswasteisnotthemeanoftheresultsforindividualloads,ObtainingmeaningfullaboratoryresultsforMSWisdif-aswithMSW.Rather,theoverallcompositionisweightedficult.Theprimarysourcesofdifficultyare(1)thepres-inaccordancewiththeweightsoftheindividualloads.AnenceofmanydifferenttypesofobjectsinMSWand(2)estimateoftheoverallpercentageofeachcomponentin-thelargesizeoftheseobjects.Collectingsmallbutrepre-volvescalculatingthetotalquantityofthecomponentinsentativesamplesfromahomogeneouspileofsmallob-allobservedloadsanddividingitbythetotalweightofjects(e.g.,apileofrice)iseasierthanfromaheteroge-allobservedloads,asillustratedbythefollowingequa-neouspileoflargeobjects.Secondarysourcesofdifficultytion:insamplingMSWincludetheunevendistributionofmois-po5(p1w11p2w2zzz1pnwn)/wo10.4(7)tureandinconsistentlaboratoryprocedures.where:po5theoverallpercentageofthecomponentintheob-MIXEDSAMPLEVERSUSCOMPONENTservedloadsSAMPLETESTINGp15thepercentageofthecomponentinthefirstob-servedloadAninitialchoicetobemadeiswhethertotestmixedsam-w15theweightofthefirstobservedloadplesorindividualwastecomponents.Testingmixedsam-p25thepercentageofthecomponentinthesecondob-plesispreferablewhen:servedloadw25theweightofthesecondobservedload•Theonlypurposeofthelaboratorytestingistopn5thepercentageofthecomponentinthelastob-determinethecharacteristicsofthemixedwasteservedloadstream,suchasheatvalue.wn5theweightofthelastobservedload•Thestatisticalprecisionofthelaboratoryresultswo5thetotalweightofallobservedloadsmustbedemonstrated.Beforetheoverallcompositioncanbecalculatedinthis•Thestudydoesnotincludesortingwastesamples.way,theweightofeachloadmustbeestimated.Ifthefa-•Nosignificantchangesinthecompositionofthecilityhasascale,environmentalengineerscandeterminewastestreamareanticipated.theactualweightoftheobservedloadsbymatchingtheTestingofindividualwastecomponentsisnecessary,offieldnotesforeachloadwiththecorrespondingentryincourse,whenthecharacteristicsofindividualwastecom-thefacilitylog,basedonthetimeofarrivalandinforma-ponentsmustbedetermined.Inaddition,componenttest-tionaboutthetruckandtheload.Thetimeofarrivalingmakesprojectingtheimpactofchangesinthecom-recordedinthefacilitylogisthetimewhenthetruckwasponentcompositionofthewaste,suchaschangescausedloggedinratherthanthetimewhentheloadwasdis-byrecyclingandcompostingprograms,possible.charged.Fieldpersonnelmustdeterminethedifferencebe-Componenttestingalsoenhancesqualitycontrolbecausetweenthetwotimes.laboratoryerrorsareeasiertodetectintheresultsforin-Ifthefacilitydoesnothaveascale,environmentalen-dividualcomponentsthaninthoseformixedsamples.gineersmustestimatetheweightofeachcomponentandTheproceduresforcollectingmixedsamplesforlabo-thetotalweightoftheloadbyconvertingfromcubicyardsratorytestingareessentiallythesameasthoseforcollect-totons.Thefollowingprocedureissuggested:ingmixedsamplesforsorting.TheprecedingevaluationThetotalvolumeoftheloadisdistributedamongthecom-oftheseproceduresalsoappliestothecollectionofmixedponentsoftheloadbasedonthefieldnotes.samplesforlaboratorytesting,exceptforthecommentsTheweightofeachcomponentisestimatedbasedonitsconcerningtheimpactsofvarioussamplingproceduresonvolumeanddensity.Table10.3.3showsdensityrangesthesortingprocess.forcertainwastecomponents.LaboratorysamplesofindividualwastecomponentsareTheestimatedcomponentweightsareaddedyieldingtheusuallycompositesubsamplesofsamplessortedtoesti-estimatedtotalweightoftheload.matecomposition.Ingeneral,eachcomponentlaboratory©1999CRCPressLLC subsampleincludesmaterialfromeachsortedsample.Plasticbuckets(andtheirlids)areeasiertolabel,andtheMaterialforthelaboratorysubsamplesiscollectedfromlabelsareeasiertoread.thesortingcontainersafterthesortingandweighingareAddingmaterialtoplasticbucketsiseasier.complete.Thelids,whichareliftedonlywhenmaterialisaddedtothebuckets,preventmoisturelossduringtheactivesam-LABORATORYPROCEDURESplingperiod.SamplematerialcanbecompactedinplasticbucketsifitAfundamentalquestionishowlargeshouldthesamplesispusheddownaroundtheinsideedge.senttothelaboratorybe.Theanswertothisquestionde-Thebucketscanbeusedasshippingcontainers.pendsontheproceduresusedbythelaboratory.Astate-Thebucketscanbereusedifthelaboratoryshipsthemof-the-artcommerciallaboratoryprocedureincludestheback.followingsteps:AportionofthesamplematerialsenttothelaboratoryisCOLLECTINGMATERIALFORweighed,dried,andreweighedtodeterminethemois-LABORATORYSUBSAMPLESturecontent.Thelimitingfactoratthisstageofthepro-cedureisusuallythesizeofthelaboratory’sdryingoven.Threegeneralmethodsforcollectingmaterialforlabora-Aportionofthedriedmaterialisgroundintoparticlesoftorysubsamplesfromcontainersofsortedwasteareblind1/8to1/4in.grabsampling,cutting(ortearing)representativepiecesAportionofthe1/8--to-1/4-inmaterialisfinelygroundintofromlargeobjects,andselectingrepresentativewholeob-asclosetoapowderaspossible.Forflexibleplastic,jectsforinclusioninthesampling.Blindgrabsamplingisdryicemustbeaddedpriortofinegrindingtomakeitthepreferredapproachforwastethatmainlyconsistsofmorebrittle.smallobjects.CuttingrepresentativepiecesisappropriateTheactuallaboratorytestisgenerallyperformedon0.5forwasteconsistingoflargeobjectswithpotentiallydif-to3gofthefinelygroundmaterial,dependingontheferentcharacteristics.Selectingrepresentativewholeob-typeoftestandthespecificequipmentandprocedures.jectsisappropriateforwastecontainingonlyafewdif-ferenttypesofobjects.Variationsonthisprocedureincludethefollowing:Blindgrabsamplesshouldbecollectedbyhandorwithananalogousgraspingtool.TheobjectiveistoextracttheMostlaboratoriesdonothaveequipmentforgrindingin-materialfromarandomlyselectedbutdefinedvolumeorganicmaterialssuchasglassandmetal.Incombus-withinthecontainerofsortedmaterial.Whenscoopsandtiontesting,thismaterialisremovedfromthesampleshovelsareusedinsamplingheterogeneousmaterials,theypriortogrinding,thenweighedandreportedasash.tendtocreatebiasbycapturingdense,smallobjectswhileFormetalstesting,metalobjectscanbecutupbyhandpushinglight,largeobjectsaway.ordrilledtocreatesmallpiecesfortesting.GlassandIncollectingsubsamplesfromcontainersofsortedceramicsaretypicallycrushed.waste,samplersmustrealizethatbecausesortingpro-Manylaboratoriesdonothavefinegrindingequipment,gressesfromlargerobjectstosmaller,theobjectsatthesotheyperformtestsonrelativelycoarsematerial.topofthecontainertendtobesmallerthanthoseattheInadditiontousingdifferentmethodsforpreparingbottom.Objectsofdifferentsizescanhavedifferentchar-wastefortesting,laboratoriesusedifferenttestmethods.acteristics,evenwithinthesamewastecategory.Therefore,Themoresamplematerialthelaboratoryreceives,thethesamplermustensurethattheobjectsatdifferentlev-morematerialtheymustexcludefromthesmallquantityelsofthecontainersarerepresentedinthesamples.ofmaterialthatistested.TherealquestionisnothowEmptyingthecontainerontoadryandreasonablycleanlargethesamplesshouldbebuthowfieldandlaboratorysurfacepriortocollectingthesubsamplemaybeneces-personnelshouldsharethetaskofreducingsamplestoasary.gramortwo.Forpracticalpurposes,themaximumquan-Ifthelaboratorysamplesaretestedformetals,objectstitysenttothelaboratoryshouldbethequantitythelab-withknownmetalscontentshouldnotberepresentedinoratoryispreparedtospreadoutandmixinpreparationthesamples.Instead,suchobjectsshouldbeweighed,andforselectingthematerialtobedried.Theminimumquan-thelaboratoryresultsshouldbeadjustedtoreflectthetityshouldbethequantitythelaboratoryispreparedtoquantitiesofmetalstheycontain.Forexample,if8ozofdryandgrindup.leadweightsarefoundin10tnofsortedwaste,theweightsCompositelaboratorysamplesaretypicallyaccumu-represent25ppmoflead.Theweightsshouldbewithheldlatedinplastictrashbags,thenboxedforshipment.Anfromthelaboratorysample,and25ppmshouldbeaddedalternativeistoaccumulatethesamplesin5-galplastictotheoverallleadconcentrationindicatedbythelabora-bucketswithlids.Plasticbucketsaremoreexpensivethantoryresults.Thisprocedureismoreaccuratethanlabora-plasticbagsbuthaveseveraladvantages:torytestingalone.©1999CRCPressLLC ReviewandUseofLaboratoryResultsTABLE10.4.4HEATVALUEESTIMATESBASEDONBOIE,CHANG,ANDDULONGLaboratoryproceduresareimperfect,anderrorsinusingEQUATIONStheproceduresandincalculatingandreportingtheresultsarecommon.Reviewingtheresultsreceivedfromalabo-Dry-BasisHHVAs-ReceivedHHVEquation(Btu/lb)(Btu/lb)ratorytoseeiftheymakesenseisimportant.Thisexer-ciseisrelativelystraightforwardforcombustioncharac-Boie73955310teristicsbecausemuchisknownaboutthecombustionChang74795370characteristicsofsolidwasteanditscomponentmaterialsDuLong75105392(seeSection10.3).IdentificationoferroneouslaboratoryAverage74615357resultsismoredifficultformetalsandtoxicorganicsub-Laboratoryvalues74465348stances.Thefollowingguidelinesapplyinanevaluationofrea-sonablenessoflaboratoryresultsforcombustioncharac-teristicsonadrybasis:sistentwithincategories.Moistureandcomponentcom-positionaremorevariable.Oneoption,therefore,istoDry-basisresultsforthepaper,yardwaste,plastics,wood,sortsamplestoestimatecomponentcompositionandhaveanddisposablediaperscategoriesshouldbeclosetosubsamplestestedformoistureonly.Then,withtheusethoseshowninTables10.3.4and10.3.5.ofthedocumentedvaluesfortheproximateandultimateGreatervariabilitymustbeacceptedinindividualresultscompositionandheatvalueofeachwastecomponent,theforfoodwaste,textiles/rubber/leather,fines,andotheroverallcombustioncharacteristicsofthewastestreamcancombustiblesbecauseofthechemicalvarietyofthesebeestimated.categories.Anotherpotentialcost-savingmeasureistoestimateTheresultforcarbonmustalwaysbeatleastsixtimestheheatvaluebasedonultimatecomposition.Severalequa-resultforhydrogen.tionshavebeenproposedforthispurpose(Niessen1995):Nooxygenresultshouldbesignificantlyhigherthan50%.Forplant-basedmaterialsandmixedfoodwaste,oxygenBOIEEQUATIONresultsshouldnotbesignificantlylessthan30%onanash-freebasis.HHV514,976C149,374H24644O12700NAmongthepapercategories,onlythosewithhighpro-14500S11692Cl111,700P10.4(8)portionsofglossypaper,suchasmagazinesandad-vertisingmail,shouldhaveashvaluessignificantlyCHANGEQUATIONgreaterthan10%.HHV515,410132,350H211,500SNitrogenshouldbebelow1%forallcategoriesexcept220,010O216,200Cl212,050N10.4(9)grassclippings,otheryardwaste,foodwaste,tex-tiles/rubber/leather,fines,andotherorganics(seeTable10.3.4).DULONGEQUATIONChlorineshouldbebelow1%forallcategoriesexceptforHHV514,095.8C164,678(H2O/8)PVCbottles,otherplastic,textiles/rubber/leather,and13982S12136.6O11040.4N10.4(10)otherorganics.Sulfurshouldbebelow1%forallcategoriesexceptotherwhere:organics.HHV5higherheatingvalueinBtu/lbThelaboratoryshouldbewillingtocheckitscalcula-Percentagesforeachelementmustbeconvertedtodec-tionsandrepeatthetestifthecalculationsarenottheimalsforuseintheseequations(i.e.,35%mustbecon-sourceoftheproblem.vertedto0.35).UsingthevaluesinTable10.3.4inthethreeequationsyieldstheresultsshowninTable10.4.4.ThesevaluesareclosetotheoverallvaluesinTable10.3.5,whicharebasedonlaboratorytestingofthesamesamplesonwhichtheultimatecompositioninTable10.3.4EstimatingCombustionisbased.Thelaboratory-basedvaluesareclosertotheav-CharacteristicsBasedonLimitederageresultsforthethreeequationsthantotheresultsforLaboratoryTestinganyindividualequation.Thecombustioncharacteristicsofindividualwastecate-goriesonadrybasisarewelldocumentedandfairlycon-—F.MackRugg©1999CRCPressLLC ReferencesKlee,A.J.1991.Protocol:Acomputerizedsolidwastequantityandcom-positionestimationsystem.Cincinnati:U.S.EPARiskReductionAmericanSocietyforTestingandMaterials.1992.StandardtestmethodEngineeringLaboratory.fordeterminationofthecompositionofunprocessedmunicipalsolid———.1993.Newapproachestoestimationofsolid-wastequantityandwaste.ASTMMethodD5231-92(September).composition.J.ofEnvir.Eng.(ASCE)119,no.2(Mar/Apr).Britton,P.W.1971.Improvingmanualsolidwasteseparationstudies.Klee,A.J.andD.Carruth.1970.Sampleweightsinsolidwastecompo-U.S.EPA(March).sitionstudies.J.oftheSanit.Eng.Div.,Proc.oftheASCE96,no.FranklinAssociates,Ltd.1992.CharacterizationofmunicipalsolidwasteSA4(August).intheUnitedStates:1992update.U.S.EPA,EPA/530-R-92-019,McCamic,F.W.(FerrandandScheinbergAssociates).1985.Wastecom-NTISno.PB92-207166(July).positionstudies:Literaturereviewandprotocol.Mass.Dept.ofEnvir.Gay,A.E.,T.G.Beam,andB.W.Mar.1993.Cost-effectivesolid-wasteMgt.(October).characterizationmethodology.J.ofEnvir.Eng.(ASCE)119,no.4Niessen,W.R.1995.Combustionandincinerationprocesses:(Jul/Aug).Applicationsinenvironmentalengineering.2ded.NewYork:MarcelHilton,D.,H.G.Rigo,andA.J.Chandler.1992.CompositionandsizeDekker,Inc.distributionofablue-boxseparatedwastestream.PresentedatSCSEngineers.1979.Municipalsolidwastesurveyprotocol.Cincinnati:SWANA’sWaste-to-EnergySymposium,Minneapolis,MN,JanuaryU.S.EPA.1992.10.5IMPLICATIONSFORSOLIDWASTEMANAGEMENTThissectionaddressesseveralaspectsoftherelationshipquantityofwasterequiringdisposalbutdoesnotreducebetweenthecharacteristicsofsolidwasteandthemeth-thequantityofmaterialtobemanaged.odsusedtomanageit.Implicationsforwastereduction,BasedonthecompositionofMSW(seeSection10.3),recycling,composting,incineration,andlandfillingarein-eachofthefollowingmeasureswouldhaveasignificantcluded,aswellasgeneralimplicationsforsolidwasteman-impactonthequantityofMSWenteringthesolidwasteagementasawhole.managementsystem:MSWisabundant,unsightly,andpotentiallyodorous;•Leavinggrassclippingsonthelawncontainsnumerouspotentialpollutants;andsupportsboth•Increasingbackyardcompostingandmulchingofdisease-causingorganismsanddisease-carryingorganisms.leavesandotheryardwastesLikeMSW,bulkysolidwasteisabundant,unsightlyand•Sellingproductsinbulkratherthaninpackages,potentiallypolluting.Inaddition,thedry,combustiblena-withtheconsumerprovidingthecontainerstureofsomebulkywastecomponentscanposeafirehaz-•Buyingnomorefoodthaniseatenard.BecauseofthesecharacteristicsofMSWandbulky•Substitutingreusableglasscontainersforpaper,waste,aprompt,effective,andreliablesystemisrequiredplastic,andsingle-useglasscontainerstoisolatesolidwastefrompeopleandtheenvironment.•ReusingshoppingbagsAbeneficialuseofsolidwasteisrelativelydifficultbe-•Placingrefusedirectlyinrefusecontainersinsteadcauseitcontainsmanydifferenttypesofmaterialsinaofusingtrashbagsrangeofsizes.Theonlyestablisheduseforunprocessed•UsingspongesandclothhandtowelsinplaceofMSWisasfuelinmass-burnincinerators(seeSectionpapertowels10.9).Evenmass-burnincineratorscannothandleun-•Continuingtouseclothingandotherproductsun-processedbulkywaste.Inthepast,unprocessedbulkytiltheyarewornout,ratherthandiscardingthemwastewasusedasfillmaterial,butthispracticeisrestrictedwhentheynolongerlooknewtoday.Ingeneral,processingisrequiredtorecoveruseful•Prohibitingdistributionofunsolicitedprintedad-materialsfrombothMSWandbulkywaste.vertisingLeavinggrassclippingsonthelawnisbecomingin-creasinglycommonbecauseofdisposalbansinsomestatesImplicationsforWasteReductionandthedevelopmentofmulchinglawnmowersthatcutWastereductionreferstoreducingthequantityofmater-theclippingsintosmallerpieces.Implementationoftheialenteringthesolidwastemanagementsystem.Wastere-otherwastereductionmeasuresonthelistisunlikelyinductionisdistinguishedfromrecycling,whichreducesthetheUnitedStatesbecausetheydonotconformtothepre-©1999CRCPressLLC vailingstandardsofconvenience,comfort,appearance,TABLE10.5.1COMBUSTIBLE,COMPOSTABLE,ANDsanitation,andfreeenterprise.RECYCLABLECOMPONENTSOFaMSWImplicationsforWasteProcessingPercentageofWasteCategoryTotalbFluctuationsinwastegenerationmustbeconsideredwhenwasteprocessingfacilitiesareplanned.IfafacilitymustCombustible,compostable,and22.6processtheentirewastestreamthroughouttheyear,itrecyclablemustbesizedtohandlethepeakgenerationrate.StorageNewspaper6.8ofMSWforlaterprocessingislimitedbyconcernsaboutCorrugatedcardboard8.6Kraftpaper1.5odorandsanitation.LimitationsonthestorageofbulkyHigh-gradepaper1.7wastearegenerallylesssevere,butlong-termstorageofMagazines&mail4.0combustiblematerialsisusuallyrestricted.Processingsystemsformixedsolidwastemustbeca-Recyclableandcombustiblebutnot2.1pableofhandlingavarietyofmaterialsinarangeofsizes.compostablePETbottles0.4Becausesolidwastedoesnotflow,itmustbehauledorHDPEbottles0.7movedbyconveyor.BecauseobjectsinMSWdonotread-Polyethylenefilmotherthan1.0ilystratifybysize,screeningofMSWgenerallyrequiresatrashbagsmixingactionsuchasthatproducedbytrommelscreens.AbrasivematerialsinsolidwastecauseabrasiveweartoRecyclablebutnotcompostable7.9orcombustiblehandlingandprocessingequipment.Heavy,resistantitemsAluminumcans0.6candamagesizereductionequipment.Sizereductionisof-Tin&bimetalfood&1.5tenrequired,however,becausebulkyitemsinsolidwastebeveragecanstendtojamconveyorsandotherwastehandlingequip-Othermetalc1.5ment.Glassfoodandbeverage4.3containersImplicationsforRecoveryofUsefulCompostableandcombustible44.7butnotrecyclableMaterialsOtherpaper17.2Yardwaste9.7AlmostallsolidwastematerialscanberecycledinsomeFoodwaste12.0wayifpeoplearewillingtodevoteenoughtimeandmoneyDisposablediapers2.5totherecyclingeffort.BecausetimeandmoneyarealwaysFines3.3limited,distinctionsmustbedrawnbetweenmaterialsthataremoreandlessdifficulttorecycle.Table10.5.1showsCombustiblebutnotcompostable17.2orrecyclablethecompostable,combustible,andrecyclablefractionsofOtherplastic7.3MSW.ThematerialslistedasrecyclablearethoseforWood4.0whichlarge-scalemarketsexistifthelocalrecyclingin-Textiles/rubber/leather4.5dustryiswelldeveloped.ThelistofrecyclablematerialsisOtherorganics1.4differentindifferentareas.Notcombustibleorcompostable5.5Approximately75%oftheMSWdiscardedintheorrecyclableUnitedStatesiscompostableorrecyclable.NosolidwasteOtheraluminum0.4districtofsubstantialsizeintheUnitedStateshasdocu-cOthermetal1.8menteda75%rateofMSWrecoveryandreuse,however.Batteries0.1Reasonsforthisincludethefollowing:Otherinorganics3.2SomerecyclablematerialbecomesunmarketablethroughaTotalrecyclable32.6contaminationduringuse.Totalcompostable67.3Asignificantfractionofrecyclablematerialcannotbere-Totalcombustible86.6coveredfromtheconsumer.aMaterialslistedasrecyclablearethoseforwhichlarge-scalemarketsexistinAportionofbothrecyclableandcompostablematerialisareaswheretherecyclingindustryiswelldeveloped.blostduringprocessing(sortingrecyclablematerialsorDerivedfromTable10.3.1.Currentlyrecycledmaterialsarenotincluded.cAsubstantialportionofthiscategoryisreadilyrecyclable,andasubstantialremovingnonrecyclableandnoncompostablematerialsportionisnot.Someofthemateriallistedhereasnonrecyclablecanberecoveredfromthewastestream).inrecyclableconditionbyanefficientferrousrecoverysystematacombustionSomecompostablematerialdoesnotdecomposeenoughfacility.tobeincludedinthefinishedcompostproductandisdiscardedwiththeprocessresidue.©1999CRCPressLLC AportionoffinishedMSWcompostcannotbemarketedintotheenvironment.Similarly,thehexavalentformofandmustbelandfilled.chromiumfoundinleadchromateistreatedthesameastheelementalchromiumusedtoplatesteeleventhoughInMSWdischargedfromcompactortrucks,mostglassthehexavalentformismoretoxicthantheelementalform.containersarestillinonepiece,andmostmetalcansareTwoextensive,recentstudiesofmetalsinindividualuncrushed.MostglassandaluminumbeveragecontainerscomponentsofMSWyieldedcontradictoryresults.Astudyareinrecyclablecondition.ManyglassfoodcontainersinCapeMayCounty,NewJerseyfoundtoxicmetalscon-andsteelcansareheavilycontaminatedwithfoodwaste,centratedinthenoncompostablecomponentsofMSWhowever.SomeoftherecyclablepaperinMSWreceived(CampDresser&McKeeInc.1991;RuggandHannaatdisposalfacilitiesiscontaminatedwithothermaterials,1992).AstudyinBurnaby,BritishColumbia,however,but50%ormoreistypicallyinrecyclablecondition.foundhighermetalsconcentrationsinthecompostableTheratioofcarbontonitrogen(C/Nratio)isanindi-componentsofMSWthanwerefoundinCapeMay(seecatorofthecompostabilityofmaterials.TomaximizetheTable10.3.6)(Rigo,Chandler,andSawell1993).compostingratewhileminimizingodorgeneration,aC/NDisposablediapersarelistedascompostableinTableratioof25/1to30/1isconsideredoptimum.Higherra-10.5.1despitetheirplasticcovers.Themajorityofthetiosreducethecompostingrate,whilelowerratiosinviteweightofdisposablediapersisfromtheurine,feces,andodorproblems.treatedcelluloseinsidethecover,allofwhichiscom-Table10.5.2showsrepresentativeC/Nratiosofcom-postable.Note,however,thatmostpeoplewrapuseddi-postablecomponentsofMSW.Controlledcompostingofapersintoaballwiththeplasticcoverontheoutside,us-foodwaste,withaC/Nratioof14/1,isdifficultunlessingthewaisttapestokeeptheballfromunraveling.largequantitiesofanothermaterialsuchasyardwasteVigoroussizereductionisrequiredtopreparethesedia-(otherthangrassclippings)aremixedintoraisethera-perballsforcomposting.tio.TheC/Nratiomovesabovetheoptimumlevelasquan-Woodisbiodegradablebutdoesnotdegraderapidlytitiesofpaperareaddedtothemixture,however.enoughtobeconsideredcompostable.ThesameistrueofPaper,leaves,andwoodyyardwasteserveaseffectivecottonandwoolfabrics,includedinthetextiles/bulkingagentsincompostingMSW,sotheadditionofarubber/leathercategoryinTable10.5.1.bulkingagentsuchaswoodchipsisgenerallyunnecessary.ThemetalscontentofMSWisamajorconcernincom-postingbecauserepeatedapplicationofcomposttolandcanraisethemetalsconcentrationsinthesoiltoharmfulImplicationsforIncinerationandlevels.CompostregulationsusuallysetmaximummetalsconcentrationsforMSWcompostappliedtoland.MostEnergyRecoveryregulationsdonotdistinguishbetweendifferentformsofTheheatvalueofMSW(4800–5400Btu/lb)islowerthanametal.Forexample,theleadinprintinginkonaplas-thatoftraditionalfuelssuchaswood(5400–7200Btu/lb),ticbagistreatedthesameastheleadinglasscrystalevencoal(7000–15,000Btu/lb),andliquidorgaseouspetro-thoughtheleadinprintinginkismorelikelytobereleasedleumproducts(18,000–24,000Btu/lb)(CampDresser&McKee1991,1992a,b;Niessen1995).TheheatvalueofMSWissufficient,however,tosustaincombustionwith-TABLE10.5.2REPRESENTATIVEC/NRATIOSOFouttheuseofsupplementaryfuel.COMPOSTABLECOMPONENTSOFHeatvalueisanimportantparameterinthedesignorMSWprocurementofsolidwastecombustionfacilitiesbecauseeachfacilityhasthecapacitytoprocessheatatacertainWasteCategoryC/NRatiorate.Thegreatertheheatvalueofaunitmassofwaste,Yardwaste29/1thesmallerthetotalmassofwastethefacilitycanprocess.Grassclippings17/1TheashandmoisturecontentofMSWishighcom-Leaves61/1paredtothatofotherfuels.MostoftheashiscontainedOtheryardwaste31/1inrelativelylargeobjectsthatdonotbecomesuspendedFoodwaste14/1inthefluegas(Niessen1995).AshhandlingisamajorPaper119/1considerationatMSWcombustionfacilities.Newspaper149/1BecauseofitshighashandmoisturecontentandlowCorrugated&kraft165/1density,MSWhaslowenergydensity(heatcontentperHigh-gradepaper248/1Magazines&mail131/1unitvolume)(Niessen1995).Therefore,MSWcombus-Otherpaper85/1tionfacilitiesmustbedesignedtoprocesslargevolumesDisposablediapers95/1ofmaterial.Fines23/1TheeffectofrecyclingprogramsontheheatvalueofMSWisnotwelldocumented.NumerousattemptshaveNote:DerivedfromTable10.3.4.beenmadetoprojecttheimpactofrecyclingbasedonthe©1999CRCPressLLC measuredheatvaluesofindividualMSWcomponents(foralsinthewasteendupintheashorareemittedintotheexample,seeCampDresser&McKee[1992a]).Littlere-air.Regulationslimittheemissionoftoxicmetals.liabledataexist,however,thatdocumenttheeffectofThetendencyofametaltobeemittedfromacombus-knownlevelsofrecyclingonthewastereceivedatoper-tionfacilityisafunctionofmanyfactorssuchas:atingcombustionfacilities.Areasonableassumptionisthatrecyclingmaterialswith•Thevolatilityofthemetalbelow-averageheatvaluesraisestheheatvalueofthere-•Thechemicalformofthemetalmainingwaste,whilerecyclingmaterialswithabove-aver-•Thedegreetowhichthemetalisboundinotherageheatvaluesreducestheheatvalueoftheremainingmaterials,especiallynoncombustiblematerialswaste.Theremovalofrecyclablemetalandglasscon-•Thedegreetowhichthemetaliscapturedbythetainersincreasesheatvalue(andreducesashcontent),airpollutioncontrolsystemwhiletherecoveryofplasticsforrecyclingreducesheatEmissionsofametalfromasolidwastecombustionfa-value.Theremovalofpaperforrecyclingalsoreducesheatcilitycannotbepredictedbasedontheabundanceofthevalue.Becauserecycledpaperhasalowmoisturecontent,metalinthewaste.itsheatvalueis30%to40%higherthanthatofMSWMercuryisthemostvolatileofthemetalsofconcern,asawhole.andasubstantialportionofthemercuryinMSWescapesTheincreaseinheatvaluecausedbyrecyclingglassandcapturebytheairpollutioncontrolsystemsatMSWcom-metalisprobablygreaterthanthereductioncausedbyre-bustionfacilities.ThequantityofmercuryinMSWhasde-cyclingpaper.Becauseplasticsaregenerallyrecycledinclinedrapidlyinrecentyearsbecausebatterymanufactur-smallquantities,thereductioninheatvaluecausedbytheirershaveeliminatedmostofthemercuryinalkalineandremovalisrelativelysmall.Themostlikelyoveralleffectcarbon–zincbatteries.Onecannotassumethatareductionofrecyclingisasmallincreaseinheatvalueandadecreaseinthequantityofmercuryinbatteriesproportionatelyre-inashcontent.ducesthequantityemittedfromMSWcombustionfacili-SulfurinMSWissignificantbecausesulfuroxides(SOx)ties,however.havenegativeeffectsandcorrodenaturalandmanmadeAllbutasmallfractionofeachmetalotherthanmer-materials.SOxcombineswithoxygenandwatertoformcurybecomespartoftheashresidueeitherbecauseitneversulfuricacid.Asolidwastecombustionfacilitymustmain-entersthefacilitystackorbecauseitiscapturedbytheairtainstacktemperaturesabovethedewpointofsulfuricpollutioncontrolsystem.Theenvironmentalsignificanceacidtopreventcorrosionofthestack.Niessen(1995)pro-ofametalincombustionashresiduedependsprimarilyvidesadditionalinformation.onitsleachabilityandthetoxicityofitsleachableforms.Likesulfur,chlorinehasbothhealtheffectsandcorro-AportionoftheashresiduefromsomeMSWcombustionsiveeffects.Combustionconvertsorganic(insoluble)chlo-facilitiesisregulatedashazardouswastebecauseoftherinetohydrochloricacid(HCl).BecauseHClishighlysol-tendencyofatoxicmetal(usuallyleadorcadmium)toubleinwater,itcontributestocorrosionofmetalsurfacesleachfromtheashunderthetestconditionsspecifiedbybothinsideandoutsidethefacility(Niessen1995).theU.S.EPA.Chlorineisacomponentofadditionalregulatedcom-Niessen(1995)andChandler&Associates,Ltd.etal.poundsincludingdioxinsandfurans.Traceconcentrations(1993)provideadditionalinformationontheimplicationsofdioxinsandfuranscanbepresentinthewasteorcanofsolidwastecharacteristicswithcombustionasadis-beformedduringcombustion.Niessen(1995)providesad-posalmethod.Niessenprovidesacomprehensivetreatiseditionaldiscussion.onwastecombustionfromtheperspectiveofanenviron-Oxidesofnitrogen(NOx)formduringthecombustionmentalengineer.ThefinalreportofChandler&Asso-ofsolidwaste,bothfromnitrogeninthewasteandintheciates,Ltd.etal.providesadetailedstudyoftherelation-air.NOxreactswithothersubstancesintheatmosphereshipsamongmetalsconcentrationsinindividualtoformozoneandothercompoundsthatreducevisibilitycomponentsofMSW,metalsconcentrationsinstackemis-andirritatetheeyes(Niessen1995).sions,andmetalsconcentrationsinvariouscomponentsofEmissionsofSOx,NOx,chlorinecompounds,andhy-ashresidueatasingleMSWcombustionfacility.drocarbonsareregulatedandmustbecontrolled(seeSection10.9andNiessen[1995]).Emissionsofhydrocar-bonsandchlorinecompoundsotherthanHClcangener-allybecontrolledbyoptimizationofthecombustionImplicationsforLandfillingprocess.MaintainingcompletecontrolofthecombustionThegreaterthedensityofthewasteinalandfill,themoreofmaterialasvariedasMSWisdifficult,however,sosmalltonsofwastecanbedisposedinthelandfill.Thedensityquantitiesofhydrocarbonsandcomplexchlorinecom-ofwasteinalandfillcanbeincreasedinavarietyofways,poundsareemittedfromtimetotime.includingthefollowing:Combustioncannotdestroymetals.Assumingthatacombustionfacilityisdesignedwithnodischargeofthe•Usingcompactingequipmentspecificallydesignedwaterusedtoquenchthecombustionash,thetoxicmet-forthepurpose(SurprenantandLemke1994)©1999CRCPressLLC •SpreadingtheincomingwasteinthinnerlayersReferencespriortocompaction(SurprenantandLemkeCampDresser&McKeeInc.1991.CapeMayCountymulti-seasonal1994)solidwastecompositionstudy.Edison,N.J.(August).•Shreddingbulky,irregularmaterialssuchaslum-———.1992a.AtlanticCounty(NJ)solidwastecharacterizationpro-berpriortolandfillinggram.Edison,N.J.(May).———.1992b.PrinceWilliamCounty(VA)solidwastesupplyanaly-Becausesolidwastecontainstoxicmaterials(seeSectionsis.Annandale,Va.(October).10.3),landfillsmusthaveimpermeablelinersandsystemsChandler,A.J.,&Associates,Ltd.etal.1993.Wasteanalysis,sampling,testingandevaluation(WASTE)program:EffectofwastestreamtocollectwaterthathasbeenincontactwiththewastecharacteristicsonMSWincineration:Thefateandbehaviourofmet-(leachate).Thelinermustberesistanttodamagefromanyals.FinalReportoftheMassBurnMSWIncinerationStudy(Burnaby,substanceinthewaste,includingsolvents.ThefirstliftB.C.).Toronto(April).(layer)ofwasteplacedonthelinermustbefreeoflarge,Niessen,W.R.1995.Combustionandincinerationprocesses:sharpobjectsthatcouldpuncturetheliner.Forthisrea-Applicationsinenvironmentalengineering,2ded.NewYork:MarcelDekker,Inc.son,bulkywasteistypicallyexcludedfromthefirstlift.Rigo,H.G.,A.J.Chandler,andS.E.Sawell.1993.DebunkingsomemythsTosomeextent,themoisturecontentofwasteplacedaboutmetals.InProceedingsofthe1993InternationalConferenceinalandfillinfluencesthequantityoftheleachategener-onMunicipalWasteCombustion,Williamsburg,VA,March30–Aprilated.Inmostcases,however,amoreimportantfactoris2,1993.thequantityoftheprecipitationthatfallsonthewastebe-Rugg,M.andN.K.Hanna.1992.MetalsconcentrationsincompostableandnoncompostablecomponentsofmunicipalsolidwasteinCapeforeanimpermeablecapisplacedoverit.MayCounty,NewJersey.ProceedingsoftheSecondUnitedStatesForadditionalinformation,seeSection10.13.ConferenceonMunicipalSolidWasteManagement,Arlington,VA,June2–5,1992.Surprenant,G.andJ.Lemke.1994.Landfillcompaction:Settingaden-—F.MackRuggsitystandard.WasteAge(August).ResourceConservationandRecovery10.6REDUCTION,SEPARATION,ANDRECYCLINGMunicipalWasteReductionoftimesitisusedandthusthenumberofsingle-useprod-uctsthataredisplaced.Wastereductionisthedesign,manufacture,purchase,orUsedhouseholdappliances,clothing,andsimilaruseofmaterials(suchasproductsandpackaging)whichdurablegoodscanbereused.Theycanbedonatedasusedreducetheamountandtoxicityoftrashgenerated.Sourceproductstocharitableorganizations.Suchgoodscanalsoreductioncanreducewastedisposalandhandlingcostsberesoldthroughyardandgaragesales,classifiedads,andbecauseitavoidsthecostofrecycling,municipalcom-fleamarkets.posting,landfilling,andcombustion.ItconservesresourcesThefollowinglistscommonsourcereductionactivitiesandreducespollution.intheprivatesectors(NewJerseyDepartmentofEnviron-PRODUCTREUSEmentalProtectionandEnergy1992):ReusableproductsareusedmorethanonceandcompeteOfficepaper.Employeesareencouragedtomaketwo-withdisposable,orsingle-use,products.Thewastereduc-sidedcopies,routememosanddocumentsratherthantioneffectofareusableproductdependsonthenumbermakingmultiplecopies,makeuseoftheelectronicbul-©1999CRCPressLLC letinboardforgeneralannouncementsratherthandis-Keepingappliancesingoodworkingorderbyfollowingtributingmemos,andlimitdistributionliststoessentialthemanufacturers’servicesuggestionsforproperoper-employees.ationandmaintenanceRoutingenvelopes.Afterlargeroutingenvelopesarecom-Wheneverintendedforuseoveralongperiodoftime,pletelyfilled,employeescanreusethembysimplypast-choosingfurniture,luggage,sportinggoods,tools,andingablankroutingformontheenvelopeface.EventoysthatstanduptovigoroususelargeenvelopesreceivedinthemailcanbeconvertedMendingclothesinsteadofthrowingthemaway,andre-toroutingenvelopesinthismanner.pairingwornshoes,boots,handbags,andbriefcasesPapertowels.C-foldtowelsarereplacedwithrolltowels.Usinglong-lastingappliancesandelectronicequipmentPrinters.Rechargedlaserprintertonercartridgesareused.withgoodwarranties.ReportsareavailablethatlistTableware.Nondisposabletableware(environmentalmugproductswithlowbreakdownratesandproductsthatprogram,chinaforconferences)isused.areeasilyrepaired.Polystyrenecontainers.Reusable,glasscontainersareused,RefertoSection3.2fordiscussionsondesigningprod-andallStyrofoamcoffeecupsinallofficeareas,shops,uctlineextension.andtheemployeecafeteriaareeliminated.Styrofoampeanutsarereusedinofficesordonatedtolocalbusi-nesses.REDUCEDMATERIALUSAGEPERBeveragesanddetergents.Someitemsareavailableinre-PRODUCTUNITfillablecontainers.Forexample,somebottlesandjugsforbeveragesanddetergentsaremadetoberefilledandReducingtheamountofmaterialusedinaproductmeansreusedbyeithertheconsumerorthemanufacturer.lesswasteisgeneratedwhentheproductisdiscarded.Cleaningrags.Reusableragsareusedinsteadofthrow-Consumerscanapplythiswastereductionapproachinawayrags.theirshoppinghabitsbypurchasingpackagedproductsinRingednotebinderreuse.Employeestakebinderstoonelargecontainersizes.Forexample,theweight-to-volumeofseveralcollectionpointsatthefacilitywheretheyareratioofametalcanforasamplefoodproductdeclinesrefurbishedforreuse.from5.96withan8-ozcontainer(singleservingsize)toLaboratorychemicals.“Just-in-time”chemicalsaredeliv-3.17witha101-oz(institutional)size.eredtolabstoprecludestockpilingchemicalswhichOthermethodsforreducingthematerialperproducteventuallygobad.Thismethodreduceshazardousunitinclude:wastedisposalcoststhroughsourcereduction.Usingwrenches,screwdrivers,nails,andotherhardwarePhotocopymachines.Newphotocopyingmachineswithavailableinloosebins.Purchasinggroceryitems,suchenergy-savingcontrolsareused.astomatoes,garlic,andmushrooms,unpackagedratherBatteries.Useofrechargeablebatteriesreducesgarbagethanprepackagedcontainers.andkeepsthetoxicmetalsinbatteriesoutofthewasteUsinglargeoreconomy-sizeitemsofhouseholdproductsstream.Usingbatterieswithreducedtoxicmetalsisan-thatareusedfrequently,suchaslaundrysoap,sham-otheralternative.poo,bakingsoda,petfoods,andcatlitter.Choosingthelargestsizeoffooditemsthatcanbeusedbeforespoiling.Usingconcentratedproducts.Theyoftenrequirelesspack-INCREASEDPRODUCTDURABILITYagingandlessenergytotransporttothestore,savingWhenaconsumer-durableproducthasalongerusefullife,moneyaswellasnaturalresources.fewerunits(suchasrefrigerators,washingmachines,andWhenappropriate,usingproductsthatarealreadyonhandtires)enterthewastestream.Forinstance,since1973,thetodohouseholdchores.Usingtheseproductscansavedurabilityofthepassengertirehasalmostdoubledasra-onthepackagingassociatedwithadditionalproducts.dialtireshavereplacedbiasandbias-beltedtires.Radialtireshaveanaveragelifeof40,000to60,000miles;theaveragelifeofbiastiresis15,000miles,andbias-beltedDECREASEDCONSUMPTIONtiresis20,000miles(Peterson1989).Seldom-useditems,likecertainpowertoolsandpartyOtherwaysofreducingwastethroughincreasedprod-goods,oftencollectdustandrust,takeupvaluablestor-uctdurabilityinclude:agespace,andultimatelyendupinthetrash.RentingorUsinglow-energyfluorescentlightbulbsratherthanin-borrowingtheseitemsreducesconsumptionandwaste.candescentones.Thesebulbslastlonger,whichmeansInfrequentlyuseditemscanbesharedamongneighbors,fewerbulbsarethrownout,andcostlesstoreplacefriends,orfamily.Borrowing,renting,andsharingitemsovertime.savebothmoneyandnaturalresources.©1999CRCPressLLC Otherwaystodecreaseconsumptionfollow.Majormanufacturersofkitchenequipmentshouldmakesortingdrawers,lazySusansortingbins,andtilt-outbinsRentingorborrowingtoolssuchasladders,chainsaws,asstandardkitchenequipment.Kitchendesignersshouldfloorbuffers,rugcleaners,andgardentillers.Inapart-keepinmindsmallconvenienceitems,suchasautomaticmentbuildingsorco-ops,residentscanpoolresourceslabelscrapers,trashchutes,andcanflattenerstomakere-andformbankstosharetoolsandotherequipmentcyclingmoreconvenient.usedinfrequently.Inaddition,somecommunitieshaveThemorefinelyhouseholdwasteisseparated,thetoollibraries,whereresidentscanborrowequipmentasgreateritscontributiontorecycling.Figure10.6.1showsneeded.anapproachwherehouseholdwasteisseparatedintofourRentingorborrowingseldom-usedaudiovisualequipmentcontainers.RentingorborrowingpartydecorationsandsuppliessuchContainer1wouldreceiveallorganicorputresciblema-astables,chairs,centerpieces,linens,dishes,andsilver-terials,includingfood-soiledpaperanddisposablediaperswareandexcludingtoxicsubstancesandglassorplasticitems.SharingnewspapersandmagazineswithotherstoextendThecontentsofthiscontainercanbetakentoacom-thelivesoftheseitemsandreducethegenerationofpostingplantthatalsoreceivesyardwastesandpossiblywastepapersewagesludgeandproducessoiladditives.Beforeoldtools,cameraequipment,orothergoodsareContainer2wouldreceiveallcleanpaper,newspapers,discarded,askingfriends,relatives,neighbors,orcom-cardboard,andcartonsforpaperprocessing,wherecon-munitygroupsiftheycanusethemtentsareseparatedmechanicallyandsoldtocommercialmarkets.REDUCINGWASTETOXICITYContainer3wouldreceivecleanglassbottlesandjarsandaluminumandtincansfreeofscrapmetalsandplas-Inadditiontoreducingtheamountofmaterialinthesolidtics.wastestream,reducingwastetoxicityisanothercompo-Container4wouldreceiveallotherwaste,includingnentofsourcereduction.Somejobsaroundthehomere-plastic,metal,ceramic,textile,andrubberitems.(Later,aquiretheuseofproductscontaininghazardouscompo-fifthcontainercouldbeaddedforrecyclableplastics.)Thenents.Nevertheless,toxicityreductioncanbeachievedbycontentsofthiscontainercanbeconsiderednonrecyclablefollowingsomesimpleguidelines.andsenttoalandfillorarecyclingplantforfurthersep-Usingnonhazardousorlesshazardouscomponents.aration.ThecontentsofthiscontainerwouldrepresentExamplesincludechoosingreducedmercurybatteriesabout12%ofthetotalMSW.andplantingmarigoldsinthegardentowardoffcer-Separatecollectionsarerequiredfortrashitemsthataretainpestsratherthanusingpesticides.Insomecases,notgeneratedonadailybasis,suchasyardwaste,brushlesstoxicchemicalscanbeusedtodoajob;inothers,somephysicalmethods,suchassandpaper,scouringpads,ormorephysicalexertion,canaccomplishthesameresultsastoxicchemicals.Whenhazardouscomponentsareused,usingonlytheamountneeded.Usedmotoroilcanberecycledataparticipatingservicestation.Leftoverproductswithhazardouscomponentsshouldnotbeplacedinfoodorbeveragecontainers.Forproductscontaininghazardouscomponents,follow-ingalldirectionsontheproductlabels.Containersmustbelabelledproperly.Forleftoverproductscontaininghazardouscomponents,checkingwiththelocalenvi-ronmentalagencyorchamberofcommerceforanydes-ignateddaysforthecollectionofwastematerialsuchasleftoverpaints,pesticides,solvents,andbatteries.Somecommunitieshavepermanenthouseholdhaz-ardouswastecollectionfacilitiesthatacceptwasteyeararound.SeparationattheSourceKitchendesignersandsuppliersofkitchenequipmentwillneedtobecomemoresensitivetotheneedsofrecycling.FIG.10.6.1Basicseparationscheme.©1999CRCPressLLC andwood,discardedfurnitureandclothing,“whiteUnfortunately,recyclingandreusearenoteasilyac-goods”suchaskitchenappliances,toxicmaterials,carbat-complishedbecauseeachtypeofplasticmustgothroughteries,tires,usedoil,andpaint.adifferentprocessbeforebeingreused.Therearehundredsofdifferenttypesofplastics,but80%ofplasticusedinconsumerproductsiseitherhigh-densitypolyethylene“BOTTLEBILLS”(milkbottles)orpolyethyleneterephthalate(largesodaIn1981SuffolkCountyonLongIslandoutlawednonre-bottles).Itisnotyetpossibletoseparateplasticsbytypesturnablesodabottles.By1983legislationhadbeenpassedbecausemanufacturersdonotindicatethetypeofplasticineightstatesrequiringa5-centdepositonallsodabot-used.Plasticpartsofautomobilesarestilluncoded,sosal-tles.TheannualreturnrateonbeerbottlesinNewYorkvagerscannotseparatethembytype.Evenifrecycledpoly-isnearly90%and80%ofsixbillionsoftdrinkandbeerstyrenewereseparatedandcouldbeusedasarawmate-bottles.Furtherimprovementwasobtainedbyraisingtherialforaplasticsrecyclingplant,suchplantsarejustdepositonnonrefillablecontainersto10centsandallow-beginningtobebuiltandwedonotknowiftheywillbeingthestatetousepartoftheunredeemeddeposits(atsuccessful.Forthesereasons,environmentalistswouldpre-presentkeptbybottlersandtotaling$64millionayear)fertostopusingplasticsaltogetherincertainapplications.toestablishrecyclingstations.Bottlebills,whilehavingachievedpartialsuccess,shouldbeintegratedintooverallrecyclingprograms,TOXICSUBSTANCESwhichincludeofficepaperandnewspaperrecycling,card-boardcollectionfromcommercialestablishments,curbsideThecarelessdisposalofproductscontainingtoxicorhaz-recycling,establishmentofbuy-backrecyclingcenters,ardoussubstancescancreatehealthhazardsifallowedtowoodwasteandmetalrecycling,glassandbottlecollec-decomposeandleachintothegroundwaterfromlandfillstionfrombarsandrestaurants,andcompostingprograms.orifvaporizedinincinerators.Sincehazardous-wasteland-Advertisingandpubliceducationareimportantelementsfillsarelimited,theavailableoptionsareeithertohaveintheoverallrecyclingstrategy.Streetsigns,doorhang-manufacturerssubstitutetoxicmaterialswithnontoxicers,utility-billinserts,andphonebook,bus,andnewspa-substancesorrecycletheproductsthatcontaintoxicma-peradvertisementsarealluseful.Themosteffectivelong-terials.Municipalitiesarejustbeginningtoconsiderthere-rangeformofpubliceducationistoteachschool-childrenquirementsoftoxic-wasterecycling.Productsthataretoxicthehabitsofrecycling.orcontaintoxicsubstancesincludepaint,batteries,tires,someplastics,pesticides,cleaninganddrain-cleaningagents,andPCBsfoundinwhitegoods(appliances).RecyclingSeparatecollectionsarealsorequiredformedicalwastes.BatteriesplayanimportantroleintherecyclingoftoxicPLASTICsubstances.Batteriesrepresenta$2.5billion-a-yearmar-Plasticsarestrong,waterproof,lightweight,durable,mi-ket.Atpresent,practicallynobatteriesarebeingrecycledcrowavable,andmoreresilientthanglass.Fortheserea-intheUnitedStates.Batterymanufacturersfeelthatrecy-sonstheyhavereplacedwood,paper,andmetallicmate-clingisneitherpracticalnornecessary;instead,theyfeelrialsinpackagingandotherapplications.Plasticsgeneratethatallthatneedstobedoneistolowerthequantitiesoftoxicby-productswhenburnedandarenonbiodegradabletoxicmaterialsinbatteries.Itisestimatedthat28millionwhenlandfilled;theyalsotakeup30%oflandfillspacecarbatteriesarelandfilledorincineratedeveryyear.Thiseventhoughtheirweightpercentageisonly7%to9%.numbercontains260,000tonsoflead,whichcandamageRecentresearchhasfoundthatpaperdoesnotdegradeinhumanneurologicalandimmunologicalsystems.Thebil-landfillseitherandbecauseofcompactioninthegarbagelionsofhouseholdbatteriesdisposedofyearlycontain170truckandinthelandfill,theoriginalvolumepercentagetonsofmercuryand200tonsofcadmium.Thefirstcanof30%inthekitchenwastebasketisreduced12%tocauseneurologicalandgeneticdisorders,thesecond,can-21%inthelandfill.Inaddition,plasticsfoultheoceancer.Somebatteriesalsocontainmanganesedioxide,whichandharmorkillmarinemammals.Otherproblemsin-causespneumonia.Whenincinerated,someofthesemet-cludethetoxicchemicalsusedinplasticsmanufacturing,alsevaporate.TheexcessiveemissionsofmercurywerethetherelianceonnonrenewablepetroleumproductsastheirreasonwhyMichigantemporarilysuspendedtheopera-rawmaterial,andtheblowingagentsusedinmakingpoly-tionoftheincineratorinDetroit,thenation’slargest.styrenefoamplastics,suchaschlorofluorocarbons(CFCs),Somestateshaverecentlyinitiatedeffortstoforceman-whichcauseozonedepletion.CFCsarenowbeingreplacedufacturerstocollectandrecycleorsafelydisposeoftheirbyHCFC-22orpentane,whichdoesnotdepletetheozonebatteries.TheBatteryCouncilInternationalhaspromptedlayerbutdoescontributetosmog.Forthesereasons,re-severalstatestopasslawsrequiringrecyclingofallusedcyclingappearstobethenaturalsolutiontotheplasticcarbatteries.InmanyEuropeancountriesusedbatteriesdisposalproblem.arereturnedtotheplaceofpurchasefordisposal.©1999CRCPressLLC Thedisposalofwhitegoods(appliancessuchasrefrig-brings$25to$35becauseoftheJapanesemarketdemand.erators,airconditioners,microwaveovens)isalsoaprob-IntheNortheastanoversupplyin1989causedthewaste-lem.Until1979appliancecapacitorswereallowedtocon-paperpricetoplummetfrom$15/tontoabout2$10/ton.tainPCBs(polychlorinatedbiphenyls).Evenaftertheban,Thisoversupplyalsoresultedinincreasedwaste-paperex-somemanufacturersweregrantedanextrayearortwotoportstoEurope,whichinturncausedthecollapseofthedepletetheirinventories.Whenwhitegoodsareshredded,waste-papermarketinHolland,wherethevalueofakilo-the“fluff”remainingaftertheseparationofmetals(con-gramofwastepaperdroppedfromeightcentstoonecent.sistingofrubber,glass,plastics,anddirt)islandfilled.Wastepapercanbeclassifiedinto“bulk”or“high”Whenitwasfoundthatthe“fluff”containsmorethan50grade.Thehighest-gradepapersaremanilafolders,hardppmofPCBs,theInstituteofScrapRecyclingIndustriesmanilacards,andsimilarcomputer-relatedpaperprod-advisedits1,800membersnottohandlewhitegoods.Theucts.High-gradewastepaperisusedasapulpsubstitute,safedisposalofPCB-containingwhitegoodswouldrequirewhereasbulkgradesareusedtomakepaperboards,con-scrapdealerstoremovethecapacitorsbeforeshredding.structionpaper,andotherrecycledpaperproducts.TheSimilartoxic-wastedisposalproblemsarelikelytoariseinbulkgradeconsistsofnewspapers,corrugatedpaper,andconnectionwithelectronicandcomputingdevices,theMPW.MPWconsistsofunsortedwastefromoffices,com-printedcircuitboardsofwhichcontainheavymetals.mercialsources,orprintingestablishments.HeavyblackAlong-rangesolutiontotoxic-wastedisposalmightbeinkusedonnewspaperreducesitsvalue,however.Thetorequiremanufacturersofnewproductscontainingtoxicvalueofthepaperisalsoreducedbythepresenceofothersubstancestoarrangeforrecyclingbeforetheproductissubstancesthatinterferewithasingle-processconversionallowedonthemarket,oratleasttoprovideinstructionintopulp,suchastheguminthebindingoftelephonedi-labelsdescribingtherecommendedstepsinrecycling.rectoriesorthechemicalcoatingofmagazines.Themosteffectivewaytocreateawaste-papermarketistoattractapulpandpapermilltothearea.TokeepPAPERsuchaplantinoperation,however,requiresahigh-gradePaperusedtobemadeofreclaimedmaterialssuchaslinenwaste-papersupplyofabout300tonsperday.Inaddi-rags.Ragsweretherawmaterialsusedbythefirstpapertion,facilitiesarealsoneededforwastewatertreatment.millbuiltintheUnitedStatesin1690inPhiladelphia.Onlyinthenineteenthcenturydidpapermillsconverttowood-pulpingtechnology.IttakesseventeentreestomakeatonNewsprintRecyclingofpaper.AllSundaynewspapersintheUnitedStates,forexample,requiretheequivalentofhalfamilliontreeseveryAlargepartofthewaste-paperproblemhastodowithweek.Whenpaperismadefromwastepaper,itnotonlynewsprint,whichmakesup8%ofthetotalMSWbysavestreesbutalsosaves4,100kWhofenergypertonweight.Some13milliontonsofnewsprintareconsumed(theequivalentofafewmonthsofelectricityusedbytheyearlyintheUnitedStates,60%importedfromCanada.averagehome),7,000gallonsofwater,60poundsofair-Connecticutrequirestheuseof20%recycledpaperinpollutingemissions,andthreecubicyardsoflandfillspacethenewspaperssoldinthestatetodayand90%by1998.andtheassociatedtippingfees.Theproductionofrecy-SuffolkCountyonLongIslandrequires40%.NewYorkcledpaperalsorequiresfewerchemicalsandfarlessStatereachedavoluntaryagreementwithitspublisherstobleaching.achievethe40%goalbytheyear2000.FloridaappliesaThepaperoutputoftheworldhasincreasedby30%ten-centwaste-recoveryfeeforeverytonofvirgininthelastdecade.In1990theUnitedStatesusedmorenewsprintusedandgrantsaten-centcreditforeverytonthan72milliontonsofpaperproducts,butonly25.5%ofrecyclednewsprintused.ofthat(18.4milliontons)ismadefromrecycledpaper.TheneteffectofsuchlegislationwillbeanincreasedThiscompareswith35%inWesternEurope,almost50%andsteadydemandforwastepaper,whichisessentialforinJapan,and70%intheNetherlands.Therearesomethesuccessofrecycling.Asthedemandforwastepaper2,000waste-paperdealersintheUnitedStateswhocol-productsrises,papermanufacturerswillalsoincreasetheirlectnearly20milliontonsofwastepapereachyear.Incapacitytoproducerecycledpaper.1988,20%ofthecollectedwastepaperwasexported,mostlytoJapan.Thewaste-papermarketisveryvolatile.Insomeloca-GLASStionsthemixedofficewasteormixed-paperwaste(MPW)hasnovalueatallandtippingfeesmustbepaidtohaveAbout13milliontonsofglassaredisposedofintheUnitedthempickedup.Therefore,whatpaysforcollectionandStateseveryyear,representingmorethan7%ofthetotalprocessingisnotthepricespaidforwastepaper,buttheMSWthatisgenerated.Butonlyabout12%ofthetotalsavingsrepresentedbynotlandfillingthemat$70/tononglassproductionisrecycled.Incomparison,Japanrecy-theEastCoast.AtonofoldnewspapersinCaliforniaclesabout50%.©1999CRCPressLLC Salvagedglasshasbeenusedinbricksandpavingmix-icalagentsthatrestoretheabilityofthe“dead”rubbertotures.“Glasphalt”canbemadefromamixtureofglassbondwithotherrubberandplasticmolecules.Thevul-andasphaltoramixof20%groundglass,10%blowcanizedor“cured”tirerubberlosesitsabilitytobonddur-sand,30%gravel,and40%limestone.Inspiteofalltheseingthevulcanizingprocess.otheruses,themainpurchasersofcrushedglassaretheCombiningoldrubberwith“virgin”rubberorplasticsglasscompaniesthemselves.Theuseofrecycledcrushedresultsinaneconomicallycompetitiveproduct.Thecostglassreducesboththeenergycostandthepollutantemis-ofvirginrubberisabout65centsapoundandpolypro-sionsassociatedwithglassmaking.Crushedglassiseas-pylenecostsabout68cents,whilethe“reactivated”prod-ilysaleable,withamarketalmostasgoodasthatforalu-uctisabout30centsapound($600/ton).minum.Manufacturersusefrom20%toasmuchas80%ofsalvagedglassintheirglass-makingprocesses.INCINERATORASHIfalltheMSWofNewYorkCitywereincinerated,theMETALSresiduewouldamountto6,000to7,000tons/day,repre-IntheUnitedStatesover15milliontonsofmetalsaredis-sentingagiantdisposalproblem.About10%byweightcardedeveryyear.Thisrepresentsalmost9%ofMSWbyoftheincineratorresidueisflyashcollectedinelectro-weight.Werecycle14%ofourmetallicwastes(nearlystaticprecipitators,scrubbers,orbagfilters;theremain-64%ofaluminum).Duringthelastfiftyyears,morethaning90%isbottomashfromtheprimaryandsecondaryhalfoftherawmaterialsusedinsteelmillswasrecycled.combustionchambers.Thisresidueisasoaking-wetcom-Atleastone-thirdofthealuminumproducedisfromre-plexofmetals,glass,slag,charredandunburnedpaper,cycledsources.andashcontainingvariousmineraloxides.ABureauofAluminumrecyclingisprofitableandwellestablishedMinestestfoundthat1,000poundsofincineratorresiduebecauseitrequiresonly5%oftheelectricpowertoremeltyielded166poundsoflarger-sizeferrousmetals,suchasaluminumasitdoestoextractitfrombauxiteore.In1990wire,ironitems,andshreddedcans.Thetotalferrousfrac-theaveragepricepaidforcrushed,baledaluminumcanstionwasfoundtobe30.5%byweight;glassrepresentedwas$1,050pertonandsome55billionaluminumcans50%ofthetotalresiduebyweight.(0.96milliontons)havebeenrecycled.TherecyclingrateCommonpracticeintheU.S.istorecoversome75%ofaluminumincreasedfrom61%in1989to63.5%inoftheferrousmetalsthroughmagneticseparationandto1990.Steelhasalsobeenrecycledforgenerations,butthelandfilltheremainingresidue.Incineratorresiduehasalsorecyclingofsteelcansisrelativelynew.Itwasnecessarybeenusedaslandfillcover,landfillroadbase,aggregateintoreducetherust-preventingtinlayeronthesteelcanscementandroadbuildingapplications,andasaggregatefirst,sothattheymightbeaddeddirectlytosteelfurnaces.substituteinpavingmaterials.Therecyclingofsteelcanshasincreasedfrom5billionIncineratorresidueisprocessedtorecoverandreusecansin1988to9billionin1990anditsmarketvaluevar-someofitsconstituentsandtherebyreducetheamountre-iedfrom$40to$70pertonin1990dependingonloca-quiringdisposal.Processingtechniquesincludetherecov-tion.eryofferrousmaterialsthroughmagneticseparation,Themainsourcesofscrapmetalsarecans,automobiles,screeningtheresiduetoproduceaggregateforconstruc-kitchenappliances(whitegoods),structuralsteel,andfarmtion-relateduses,stabilizationthroughtheadditionoflimeequipment.Thevalueofthenoncombustiblesinincinera-(whichtendstominimizemetalleaching),andsolidifica-torashvariesfromareatoarea.tionorencapsulationoftheresidueintoasphalticmix-tures.Anincinerator-residueprocessingplantmightconsistofRUBBERthefollowingoperations:(1)flyashandbottomashareIntheUnitedStatessometwobillionoldtireshavebeencollectedseparately,withlimemixedonlywiththeflyash;discarded,andtheirnumberisgrowingbyabout240mil-(2)ferrousmaterialsareremovedfromthebottomash;lionayear.Inthepasttireswereeitherpiled,landfilled,(3)theferrous-freeresidueisscreenedtoseparateouttheburned,orgroundupandmixedwithasphaltforroadproperparticlesizesforuseasaggregate;and(4)there-surfacing.These“solutions”wereexpensiveandoftenmainingoversizeditemsandstabilizedflyashareland-causedenvironmentalproblemsbecauseoftheairpollu-filled.Inamoresophisticatedash-processingplant,thefer-tionresultingfrommassivetirefires.Somenewerrubberrousremovalandshredding(oroversizeremoval)arerecyclingprocesseshavetriedtoovercometheselimita-followedbymeltingoftheash(fusion),resultinginaglassytions.Thenewprocessesdonotpolluteairorwaterbe-end-product.Thishigh-techprocesshassomesubstantialcausenothingisburnedandnowaterisused.Thetiresadvantages:Itburnsallthecombustiblematerials,includ-areshreddedandthepolyesterfibersremovedbyairclas-ingdioxinsandothertraceorganics,andencapsulatesthesification.Thesteelfromradialtiresisremovedmagneti-metals,therebypreventingtheirleachingout.Theresult-cally.Theremainingrubberpowderismixedwithchem-ingfusedproductisaglazed,nonabrasive,lightweight©1999CRCPressLLC TABLE10.6.1INCINERATORASHCOMPOSITIONTABLE10.6.2COMPOSITIONOFINCINERATORASH(UNDER-20FRACTION)ComponentPercentageComponentPercentageFerrousmetal35Glass28Glass37MineralsandAsh16Mineralsandash21Ceramics8Ferrousmetals19Combustibles9Ceramics9NonferrousMetal4Combustibles8Nonferrousmetals6blackaggregate.ThefusionofcombinedincineratorashandsewagesludgeiscurrentlypracticedinJapan.differedsubstantiallyfromthecompositionoftheunder-ThefirstU.S.buildingtobebuiltfromrecycledincin-20(50.8mm)fraction(Table10.6.2).Thetestalsocon-eratorashblocksisan8,000-square-footboathouseoncludedthattheNewYorkStateDepartmentofthecampusoftheStateUniversityofNewYorkatStonyTransportationspecificationsforType3asphaltbinderBrook,LongIsland.Theashcomesfromanincineratorincanbemetif10%combinedincineratorashismixedinPeekskillandismixedwithsandandcementtoformwith90%naturalaggregate.blocksthatareasdurableasstandardcinderblocks.ThistechnologyhasalreadybeenusedinEurope.Theblocks—BélaG.Liptákcanbeusedtobuildseawalls,highwaydividers,andsoundbarriers,inadditiontoregularbuildings.Itisthebottomash(nottheflyash)portionthatisconsideredsafeforReferencessuchapplications.NewJerseyDepartmentofEnvironmentalProtectionandEnergy.1992.TheashproducedbyoneNewYorkCityincineratorHowtoreducewasteandsavemoney:Casestudiesfromtheprivatehasbeenextensivelysampledandevaluated.Flyashcon-sector.DivisionofSolidWasteManagement,OfficeofRecyclingandtainssubstantialquantitiesoforganicmaterials.AboutPlanning,BureauofSourceReductionandMarketDevelopment,20%byweightislargerthan20(50.8mm);themetalcon-Trenton,N.J.(July).tentofthisfractionisover80%byweight.TheoverallPeterson,Charles.1989.Whatdoes“wastereduction”mean?WasteAge(January).compositionofalltheincineratorresidue(Table10.6.1)10.7MATERIALRECOVERYTherecyclingofpostconsumermaterialfoundinMSWin-RoleofMRFsandMRF/TFsvolves(1)therecoveryofmaterialfromthewastestream,MaterialRecoveryFacilities(MRFs)andMaterial(2)intermediateprocessingsuchassortingandcompact-Recovery/TransferFacilities(MRF/TFs)areusedascen-ing,(3)transportation,and(4)finalprocessingtoprovidetralizedfacilitiesfortheseparation,cleaning,packaging,arawmaterialformanufacturers.Thissectionemphasizesandshippingoflargevolumesofmaterialrecoveredfromseparationandrecovery,andapplicablespecificationsforMSW.Theseprocessesinclude:thesematerials.Itfocusesonthosematerialswhicharein-tendedforshort-termconsumerusage,arediscardedFurtherprocessingofsource-separatedwastesfromcurb-quickly,andarepresentinlargequantitiesinthesolidsidecollectionprograms.Thetypeofsource-separatedwastestream.materialthatisseparatedincludespaperandcardboard©1999CRCPressLLC frommixedpaperandcardboard;aluminumfromcom-veyorisdischargedtoaconveyorlocatedbelowthepick-mingledaluminumandtincans;plasticsbyclassfromingplatformthatisusedtofeedthebaler.Oncethepa-commingledplastics;aluminumcans,tincans,plastics,perhasbeenbaled,thecardboardisbaled.andglassfromamixtureofthesematerials;andglassThePaperStockInstituteofAmerica,whichrepresentsbycolor(clear,amber,andgreen).buyersandprocessorsofwastepaper,haslistedthirty-SeparatingcommingledMSW.Alltypesofwastecompo-threespecialtygradeswhosespecificationsareagreeduponnentscanbeseparatedfromcommingledMSW.Wastebybuyersandsellers.Table10.7.1givesthespecificationsistypicallyseparatedbothmanuallyandmechanically.forthemostcommongradesofpostconsumerwastepa-ThesophisticationoftheMRFdependson(1)thenum-per.berandtypesofcomponentstobeseparated,(2)theThefourgradesfromlowesttohighestqualityarenewswastediversiongoalsforthewasterecoveryprogram,(grade6),specialnews(grade7),specialnewsde-inkqual-and(3)thespecificationstowhichtheseparatedprod-ity(grade8),andover-issuenews(grade9).Grades6anductsmustconform.7areusedprimarilyintheproductionofinsulationandpaperboardaswellasinotherapplicationswherehighquality(absenceofcontamination)isnotofforemostim-MRFsforSource-SeparatedWasteportance.Grade8isusedtomakenewspaperagain,asisMRFsforsource-separatedwastefurtherseparatepapergrade9.Grade9isthegradethatsellersfindprovidestheandcardboard,aluminumandtincans,andplasticandmostaccessiblemarket.glass.Papershippedtoapapermillmustmeetmillspecifi-cationsonoutthrowsandprohibitedmaterials.OutthrowsaredefinedasallpapersthataresomanufacturedorPAPERANDCARDBOARDtreatedorareinsuchformtobeunsuitableforcon-Theprincipaltypesofpaperrecycledareoldnewspapersumptionasthegradespecified.Prohibitivematerialsare(ONP),oldcorrugatedcardboard(OCC),high-gradepa-definedas:per,andmixedpaperwaste(MPW).ThesewastepapersAnymaterialinthepackingofpaperstockwhosepres-canbeclassifiedintobulkorhigh-grade.Thehighestgradeenceinexcessoftheamountallowedmakesthepack-ofpapersaremanilafolders,hardmanilacards,andsim-agingunsalableasthegradespecifiedilarcomputer-relatedpaperproducts.Thebulkgradecon-Anymaterialthatmaybedamagingtoequipmentsistsofnewspapers,corrugatedpaper,andMPW.MPWconsistsofunsortedwastefromoffices,commercialThemaximumamountofoutthrowsingradespecifi-sources,orprintingestablishments.High-gradewastepa-cationsisthetotalofoutthrowsandprohibitivemateri-perisusedasapulpsubstitute,whereasbulkgradesareals.Examplesofprohibitivematerialsaresunburnednews-usedtomakepaperboards,constructionpaper,andotherpaper,foodcontainers,plasticormetalfoils,waxedorrecycledpaperproducts.Theheavyblackinkusedontreatedpaper,tissuesorpapertowels,boundcatalogsornewspaperreducesitsvalue.Thevalueofpaperisalsore-telephonedirectories,Post-its,andfaxesorcarbonlesscar-ducedbythepresenceofothersubstancesthatinterferebonpaper.Otherprohibitivematerialsareforeignmate-withthesingle-processconversionintopulp,suchasgumrialssuchasdirt,metal,glass,foodwastes,paperclips,inthebindingoftelephonedirectoriesorthechemicalcoat-andstring.ingofmagazines.Toensurequalityandminimizehandlingandprocess-ALUMINUMANDTINCANSing,ONPshouldbeseparatedfromallotherwasteatorascloseaspossibletoitssourceofgeneration.EndusersAluminumcansareoneofthemostcommonitemsre-canrejectanentireshipmentofONPwhereevidenceex-coveredthroughmunicipalandcommercialrecyclingpro-iststhatthepaperwascommingledwithMSW.Caremustgramsbecausetheyareeasilyidentifiedbyresidentsandalsobetakentopreventcontaminationofthepaperdur-employers.Theyalsoprovidehigherrevenuesthanotheringcollection,loading,transporting,unloading,process-recyclablematerials.Therecyclingofusedbeveragecansing,andstoring.(UBCs)notonlysavesvaluablelandfillspacebutalsomin-InMRFs,mixedpaperandcardboardareunloadedimizesenergyconsumptionduringthemanufacturingoffromthecollectionvehicleontothetippingfloor.There,aluminumproducts.Manufacturingnewaluminumcanscardboardandnonrecyclablepaperitemsareremoved.fromUBCsuses95%lessenergythanproducingthemThemixedpaperisthenloadedontoafloorconveyorwithfromvirginmaterials.afront-endloader.ThefloorconveyordischargestoanAsuccessfulaluminumrecyclingprogrammusthavein-inclinedconveyorthatdischargesintoahorizontalcon-teractionbetweenvariousentitiesincludingthoseinvolvedveyor.Thehorizontalconveyortransportsthemixedpa-withcollection,sortingandprocessing,reclamation,andperpastworkerswhoremoveanyremainingcardboardreuse.Threegeneratorsectorsfromwhichaluminumbev-fromthemixedpaper.Thepaperremainingonthecon-eragecontainerscanberecoveredareresidentialhouse-©1999CRCPressLLC TABLE10.7.1SPECIFICATIONSFORRECYCLEDPAPERANDCARDBOARDProhibitiveTotalGradeMaterials,Outthrows,NumberClassDescription%%1MixedAmixtureofvariousqualities210Paperofpapernotlimitedtotypeofpackingorfibercontent6NewsBalednewspapers0.52.0containinglessthan5%otherpapers7SpecialBaled,sorted,fresh,dryNone2.0Newsnewspapers;notsunburned;freefrompermittedpaperotherthannews;containingnotmorethanthenormalpercentageofrotogravureandcoloredsections8SpecialBaled,sorted,fresh,dryNone0.25News,De-inknewspapers;notsunburned;freefrompermittedQualitymagazines,whiteblank,pressroomoverissues,andpaperotherthannews;containingnotmorethanthenormalpercentofrotogravureandcoloredsections.Thispackagingmustbefreefromtar.9OverissueUnused,overrun,regularNoneNonenewspaperprintedonnewsprint;baledorsecurelypermittedpermittedtiedinbundles;containingnotmorethanthenormalpercentageofrotogravureandcoloredsections11CorrugatedBaled,corrugatedcontainers,1.05.0Containershavinglinersoftestliner,jute,orkraft38SortedColoredPrintedorunprintedsheets,None2.0Ledgercoloredshavings,andcuttingsofcoloredpermittedorledgerwhitesulfiteorsulfateledger,bond;andwritingandotherpapersthathaveasimilarfiberandfillercontent.Thisgrademustbefreeoftreated,coated,padded,orheavilyprintedstock.40SortedPrintedorunprintedsheets,None2.0WhiteLedgerguillotinedbooks,quirewaste,andpermittedcuttingsofwhitesulfiteorsulfateledger,bond,andwritingandotherpapersthathaveasimilarfiberandfillercontent.Thisgrademustbefreeoftreated,coated,padded,orheavilyprintedstock.42ComputerWhitesulfiteorsulfateNone2.0Printoutpapersinformsmanufacturedforuseinpermitteddataprocessingmachines.Thisgradecancontaincoloredstripesandimpactornonimpact(e.g.,laser)computerprinting,andcancontainnotmorethan5%ofgroundwoodinthepacking.Allstockmustbeuntreatedanduncoated.Source:PaperStockInstitute,Guidelinesforpaperstock(Washington,D.C.:InstituteofScrapRecyclingInc.).©1999CRCPressLLC holds,commercialinstitutions,andmanufacturingentities.45LDPE(low-densitypolyethylene)Curbsidecollectionprogramsrecapturelargequantitiesof55PP(polypropylene)recyclables.AluminumUBCscanbeseparatedasanindi-65PS(polystyrene)vidualcommodityorcommingledwithotherrecyclables.75Other(allotherresinsandmultilayeredmaterial)Steelfoodcans,whichmakeupmorethan90%ofallfoodcontainers,areoftencalledtincansbecauseoftheStill,keepingplasticsseparateisnoteasy.Themostno-thintincoatingusedtoprotectthecontentsfromcorro-toriouslookalikesarePET,theclear,shinyplasticthatsion.Somesteelcans,suchastunacans,aremadewithsodabottlesaremadefrom,andPVC,anotherclearplas-tin-freesteel,whileothershaveanaluminumlidandasteelticusedmainlyforpackagingcookingoil.BecausePVCbodyandarecommonlycalledbimetalcans.AllthesestartstodecomposeatthetemperatureatwhichPETisemptycansarecompletelyrecyclablebythesteelindustryjustbeginningtomelt,onestrayPVCbottleinameltofandshouldbeincludedinanyrecyclingprogram.10,000PETbottlescanruintheentirebatch.AttheMRF,thecollectionvehicledischargesthecom-Containerglassistheonlyglassbeingrecycledtoday.mingledaluminumandtincansintoahopperbin,whichWindowpanes,lightbulbs,mirrors,ceramicdishesanddischargestoaconveyorbelt.Theconveyortransportsthepots,glassware,crystal,ovenware,andfiberglassarenotcommingledcanspastanoverheadmagneticseparatorrecyclablewithcontainerglassandareconsideredconta-wherethetincansareremoved.Thebeltcontinuespastaminantsincontainerglassrecycling.pulleymagneticseparator,whereanytincansnotremovedTheconsiderationincontainerglassmarketingiscolorwiththeoverheadmagnetaretakenout.Thealuminumseparation.Permanentdyesareusedtomakedifferentcol-andtincans,collectedseparately,arebaledforshipmentoredglasscontainers.Themostcommoncolorsaregreen,tomarkets.brown,andclear(orcolorless).Intheindustry,greenglassAtareclamationplant,shreddedaluminumcansareiscalledemerald,brownglassisamber,andclearglassisfirstheatedinadelacqueringprocesstoremovecoatingsflint.Forbottlesandjarstomeetstrictmanufacturingspec-andmoisture.Thentheyarechargedintoaremeltingfur-ifications,onlyemeraldorambercullet(crushedglass)cannace.Moltenmetalisformedintoingotsof30,000lborbeusedforgreenandbrownbottles,respectively.morethataretransferredtoanothermillandrolledintoAttheMRF,thecollectionvehicledischargesthecom-sheets.Thesheetsaresenttocontainermanufacturingmingledplasticandglassintoahopperedbin,whichdis-plantsandcutintodisks,fromwhichcansareformed.chargestoaconveyorbelt.ThematerialistransportedtoAluminummarketshavematerialspecificationsthatasortingarea,wheretheplasticandglassareseparatedregulatetheextentofcontaminationallowedineachde-manuallyfromtheothermaterials.Theremainingglassisliveryaswellasthemethodbywhichmaterialsarepre-colorsortedandsenttoaglasscrusher.Thewasteisdis-pared.Forexample,somemarketsprohibitaluminumfoilschargedtovibratingscreenswherebrokenglassfallsandaluminumpansbecausetheyareusuallycontami-throughtheopeningsinthescreen.Anyresidualmateri-nated.Noncontaineraluminumproductspurchasedbyalsiscollectedattheendofthevibratingscreen.Thedealersmustsimplybedryandfreeofcontaminants.crushedglassisloadedontolargetrailersandtransportedtothevibratingscreen.Theresidualmaterialisdisposedofinalandfill.Thecommingledplasticisseparatedfur-PLASTICANDGLASStherbyvisualinspectionoraccordingtothetype(PETandTherecyclingandreuseofplasticsarenoteasilyaccom-HDPE)basedontheimprintedcodeadoptedbytheplas-plishedbecauseeachtypeofplasticmustgothroughadif-ticindustry.ferentprocessbeforebeingreused.HundredsofdifferentInaglassbottlemanufacturingplant,specializedben-typesofplasticsexist,but80%oftheplasticsusedincon-eficiationequipmentperformsfinalcleaningtoremovesumerproductsiseitherHDPE(milkanddetergentbot-residualmetals,plastic,andpaperlabels.Theculletisthentles)orpolyethyleneterephthalate(PET)(largesodabot-mixedwiththerawmaterialusedintheproductionoftles).Themostcommonitemsproducedfromglass.Afterthebatchismixed,itismeltedinafurnaceatpostconsumerHDPEaredetergentbottlesandmotoroiltemperaturesrangingfrom2600to2800°F.Themixcancontainers.Detergentbottlesareusuallymadeofthreelay-burnatlowtemperaturesifmoreculletsareused.Theers,withthecenterlayercontainingtherecycledmaterial.meltedglassisdroppedintoaformingmachinewhereitMostplasticcontainermanufacturerscodetheirprod-isblownorpressedintoshape.Thenewlyformedglassucts.Thecodeisatrianglewithanumberinthecentercontainersareslowlycooledinanannealinglehr.Theyandlettersunderneath.Thenumberandletterindicatetheareinspectedfordefects,packed,andshippedtothebot-resinfromwhichthecontainerismade:tler.Atareclamationfacility,PETbottlesandHDPEjugs15PET(polyethyleneterephthalate)aretransformedintocleanflakes.Aresinreclamationfa-25HDPE(high-densitypolyethylene)cilitychopsandwashesthechipstoremovelabels,adhe-35V(vinyl)sives,anddirtandseparatesthematerialfromtheircom-©1999CRCPressLLC TABLE10.7.2SPECIFICATIONSFORCOLOR-ware.Thesematerials,knownasrefractorymaterials,haveSORTEDGLASShighermeltingtemperaturesthancontainerglassandformasolidinclusioninthefinishedproduct.Table10.7.2givesPermissibleColorMixLevels,Percentthematerialspecificationsforcolor-sortedglass.Thespec-ColorFlintAmberGreenOtherificationsintheRotterdamglassprocessingplantlimitthemaximumamountofceramicsto100gpertonofcrushedFlint(clear)97to1000to30to10to3glass;thesamelimitforaluminumisonly6gperton.Amber(brown)0to595to1000to50to5Tradegroupsrepresentingmanufacturersandproces-Green0to100to1585to1000to10sorshaveestablishedspecificationsforrecycledplastics.Source:AmericanSocietyforTestingandMaterials(ASTM),1989,StandardThesespecificationsareextensiveandbeyondthescopeofspecificationsforwasteglassasarawmaterialforthemanufactureofglasscon-thischapter.Ingeneral,buyersrequirepostconsumerplas-tainers,1989Annualbookofstandards,Vol.11.04(Phila.:ASTM),299–300.ticstobewellsorted,reasonablyfreeofforeignmaterial,andbaledwithinaspecifiedsizeandweightrange.ponentstoproduceacleangenericpolymer.CleanPETissoldasflakesbutmostHDPEismadeintopellets.TheMSWProcessingHDPEflakesarefedintoanextruderandarecompressedastheyarecarriedtowardtheextrusiondie.ThecombinedAsolidwasteprocessingplantinRhodeIslandandtheheatfromflowfrictionandsupplementalheatingbandsSorain-CechiniMRFplantinRome,Italyaretwoexam-causestheresintomelt,andvolatilecontaminantsareplesofMSWprocessingplants.ventedfromthemixture.Immediatelybeforethedie,themeltedmixturepassesthroughafinescreenthatremovesMRFPLANTFORPARTIALLYanyremainingsolidimpurities.AsthemeltpassesthroughSEPARATEDMSWtheorifice,arotatingknifechopsthestrandintoshortseg-ments,whichfallintoawaterbathwheretheyarecooled.In1989,an80tonsperday(tpd)MRFwasstartedinThepelletsaredriedtoamoisturecontentofabout0.5%RhodeIsland(seeFigure10.7.1).Designedandoperatedandarepackagedforshipmenttotheenduser.byNewEnglandCRInc.inconjunctionwithMasch-GlassusedfornewbottlesandcontainersmustbeinenfabrikBeznerofWestGermany,thishighlyautomatedsortedbycolorandmustnotcontaincontaminantssuchplantcansortandrecovertherecyclablesfrompartiallyasdirt,rocks,ceramics,andhigh-temperatureglasscook-separatedMSWcontainingmetallic,glass,andplasticFIG.10.7.1TheoperationofasolidwasteprocessingplantinRhodeIsland.(Reprinted,withpermission,fromNewEnglandCRInc.,1989,NewYorkTimes/BohdanOsyczka,[2May],160.)©1999CRCPressLLC cans,bottles,andothercontainersbutnotpaperandor-plastics(1%)whilegeneratingdensifiedRDF(51%)andganics.ThepartiallyseparatedMSWenterstheplantonrejecting7%oversizeditems.Thetotalplantcapacityisaconveyorbelt,whichfirstpassesunderanelectromag-1200tnperday(CachinandCarrera1986).netthatattractsthetin-platedsteelcansandcarriesthemThemainprocessingstepsinvolvemagneticseparationofftobeshredded.AstheMSWfalls,itencountersarollingforferrousmetalremoval,eddy-currentseparationforalu-curtainofchains.Thelighterobjects(aluminumandplas-minumrecovery,rotaryscreensforseparationbysize,andticcans)cannotbreakthroughandaredivertedtowardaairclassifiersforseparationbydensity.Theoverallprocessmagnetizeddrum.Theheavier(mostlyglass)bottlespassconsistsofeightypiecesofequipment,whichareflexiblethroughthecurtainandarriveatahand-separationbelt,andcanbeusedindifferentcombinationsasmarketcon-wheretheyareseparatedmanuallybycolor.ditionschange.Astheplasticandaluminumcontainersreachthemag-Figure10.7.2showstheresourcerecoveryplantinneticdrum,thealuminumobjectsdropintoaseparateRome.Thechargingconveyor1isprovidedwithapickuphopper.Theplasticobjectscontinueontheconveyorbeltdevice2thatbreaksthebagsandremovesbulkyrejectandarelatersortedaccordingtoweight.items.Alevelingdevice3metersthewaste-flowrateandTheplantdesignappearstobesimpleenoughtoguar-removesrejects.Theprimaryscreen4separatesthelargeanteereliability.TheconceptofthistypeofMRFplantis(over8in)fractionfromthesmaller,heavierfraction.Thepromisingbecauseitsimplifiestheprocessofsourcesep-approximately55%largefractionofpaper,wood,andarationbyallowingcansandcontainersofalltypestobeplasticisfedtothe10–20rpmlargebreaker5,whichre-placedinthesamebin.ducesparticlesizeandbreaksplasticbags.Thelargebreakerautomaticallyrejectsanyitemsitcannotbreak(about2%).Theoutput(53%)issenttothelargeairclas-sifier6,wherethelighter(10%)sheetpaperandplasticMATERIALRECOVERYPLANTfractionisseparatedfromtheheavier(43%)cardboard,TheSorain-CecchiniMRFplantinRomehasbeeninop-wood,andrags.Therejectfractionconsistsmostlyofwhiteerationforovertwentyyears.Itrecoversferrousmetalsgoods(appliances)butincludesbulkyitemssuchasbed-(6%byweight),aluminum(1%),organics(34%),andfilmsprings.Thisfractionishauledawaybysubcontractors.FIG.10.7.2ResourcerecoveryplantinRome,Italy.(AdaptedfromF.J.CachinandF.Carrera,1986,TheSorain-Cecchinisystemformaterialrecovery,NationalWasteProcessingConference,Denver,1986[ASME].)©1999CRCPressLLC Thelightfraction(10%)passesthroughadifferentialisfollowedbycleaningthroughfiringorwashingandashredder7,whichbreaksuponlythepaper.Itisfollowedfinalmagneticseparationsteptoremovethenonmetalsbyarotaryscreen8,whichseparatesthelighter3%ofthethatwereloosenedbytheabrader.stream,containingtheplasticfilm.ThisstreamissenttoTheorganicsfraction,leftfromtheplantfeedafterthethesmallclassifier9,wherethe1%lightfractionistakenremovalofmetals,plasticfilm,andpaper,isessentiallyatoplasticrecovery,whiletheremainingpaperandragfrag-heavyfractionofsmall-sizedparticlescontainingorganics,mentsareincludedwiththedensifiedRDF(DRDF).Theglass,ceramics,sand,ashes,hardplastics,andsmallpiecesrecoveredplasticfilm(mostlypolyethylene)isshreddedofwood.Thisfractionisplacedintoanaerobicdigesterintosquare-inchflakes,cleanedbywashing,andairdried.andbrokendownintorawcompost.AftertheremovalofThedryflakesaremeltedandfedtotheextruder,andtheglass,ceramics,andotherinorganicrejects,therawcom-pelletsareshippedtoplasticfilmmanufacturers.postissubcontractedforfurtherprocessing.Thisprocess-Formetalseparation,the40%heavyfractionfromtheingsplitstheorganicfractionintoafeedfraction(ahigh-primaryscreen4passesthroughtheprimarymagneticsep-qualitycompostfraction)andaresidue,whichisusuallyarator10,whichremoves4%andsendsthatfractiontolandfilled.ferrousrecovery.Theremainingfractionisfurtherho-The15%largefractionfromthesecondaryrotarymogenizedinthesmallbreaker11andseparatedinthescreen8andthe30%fromtheflail14aresenttothesec-secondaryrotaryscreen8intothe15%largefraction(overondaryairclassifier15,whichremovesallpaper(35%)4in),consistingmainlyofpaper,wood,andplastics,andandsendsittotheDRDFairclassifier19togetherwithissenttoDRDFrecovery.The21%smallfraction(underthesmallfraction(7%)fromthesecondaryrotaryscreen4in),consistingoforganics,glass,ashes,andaluminum,8andtheheavyfraction(2%)fromthesmallairclassi-issenttoaconveyor17;aluminum(1%)isremovedbyfier9.AftertheDRDFmagnetic18removestheremain-hand,andtherest(20%)issenttoorganicrecovery.ingferrousmetals,theDRDFisdensifiedintoflakesintheThe43%heavyfractionfromthelargeairclassifier6recoveryline.TheDRDFisstoredinaspecificgravityofpassesthroughthesecondarymagneticseparator12,0.6(38lb/ft).Theheavyfraction(10%)fromthesec-whichremoves1%andsendsthatfractiontoferrousre-ondaryairclassifier15issenttoorganicrecovery.covery.Theremainingfractiontravelsonthesortingcon-TheDRDFobtainedisrelativelyclean,anditssulfurveyor13,wherethesemiautomaticdevicesandinspectorsandchlorinecontentislowasmostmetals,hardplasticsremovethecardboard(8%),whichissentDRDF.Any(PVC,PET),andotherimpuritieshavebeenremovedfrommissedrecoveryitemsandrejects(4%)aresenttotheeddy-it.TheSorainprocesscanswitchfromproducingDRDFcurrentseparator16foraluminumrecoveryandthentotogeneratingpaperpulpdependingonmarketcondition.organicrecovery.Theremovedaluminumiscrushedanddensifiedtoaspecificgravityof1.0(62.4lb/cuft)beforeAdaptedfromMunicipalWasteDisposalinthe1990sbeingplacedinstorage.The30%fractionremainingonbyBélaG.Lipták(Chilton,1991).thesortingconveyor13ismostlypaperandissenttotheflail14,whereitisbrokendownbeforebeingsenttotheReferencesecondaryairclassifier15.ThethreemagneticseparatorsCachin,F.J.andF.Carrera.1986.TheSorain-Cechinisystemformate-10,12,and18send5.8%toferrousrecovery,whereitisrialrecovery.NationalWasteProcessingConference,Denver,1986.shreddedbytheabraderhammermill.TheshreddingstepASME.©1999CRCPressLLC 10.8REFUSE-DERIVEDFUEL(RDF)RDFisthecombustibleportionofMSWthathasbeen250,000-lb/hrboilerdesignedforRDFservice.Inthisfa-separatedfromthenoncombustibleportionthroughpro-cility,1300tpdofMSWareseparatedinto983tpdofcessingsuchasshredding,screening,andairclassifying.RDFfuel,260tpdofglassyresiduewhicharelandfilled,TheRDFthatremainsafterprocessingishighlycom-and57tpdofferrousmetalswhicharesold.TheMSWbustibleandcanbeusedasis(fluffymaterial)orinpelletpassesthroughtwoparallel70tphHeilshredderspro-form.ducinganoutputparticlesizeof90%under4in(101.6mm).Theferrousmetalsareremovedbydingsandheadpulleymagnets.RDFPreparationPlantTheshreddedrefusepassesthroughatwo-stage,12.5-Figure10.8.1showstheprocessflowdiagramoftheRDFftdiameter,60-ftlong(3.8m318.24m)trommelscreen.preparationplantinHaverhill,Massachusetts.ThisplantThefirststagehas1-inholestoremovetheglassyresidue.hasbeenoperatingsince1984,feeding100%RDFtoaThesecondstagehas6-in(152.4mm)holesthatseparateFIG.10.8.1RDFpreparationplantinHaverhill,Massachusetts.(Reprinted,withpermission,fromD.Kaminski,1986,PerformanceoftheRDFdeliveryandboiler-fuelsystematLawrence,Massachusettsfacility,NationalWasteProcessingConference,Denver,1986[ASME].)©1999CRCPressLLC TABLE10.8.1ASTMCLASSIFICATIONOFRDFSClassFormDescriptionRDF-1(MSW)RawMSWwithminimalprocessingtoremoveoversizebulkywasteRDF-2(C-RDF)CoarseMSWprocessedtocoarseparticlesizewithorwithoutferrousmetalseparationsuchthat95%byweightpassesthrougha6-insquaremeshscreenRDF-3(f-RDF)FluffShreddedfuelderivedfromMSWprocessedfortheremovalofmetal,glass,andotherentrainedinorganics;particlesizeofthismaterialissuchthat95%byweightpassesthrougha2-insquaremeshscreenRDF-4(p-RDF)PowderCombustiblewastefractionprocessedintopowderedformsuchthat95%byweightpassesthrougha10meshscreen(0.035in.square)RDF-5(d-RDF)DensifiedCombustiblewastefractiondensified(compressed)intopellets,slugs,cubettes,briquettes,orsimilarformsRDF-6LiquidCombustiblewastefractionprocessedintoaliquidfuelRDF-7GasCombustiblewastefractionprocessedintoagaseousfuelSource:R.E.Sommerlandetal.,1988,Environmentalcharacterizationofrefuse-derived-fuelincineratortechnology,NationalWasteProcessingConference,Philadelphia,1988(NewYork:ASME).theoversizedmaterialforfurthershreddingandsendtheModelingRDFPerformanceunder-6-infractiontoRDFstorage.TheRDFproducedhasaheatingvalueofover6000Btu;theashcontentisAscommunityrecyclingincreases,thefeedtoanRDFlessthan15%,anditsparticlesizeis97%under4inplantchanges.Studieshavedeterminedtheheatingvalue(101.2mm).andcompositionofRDFfromdifferentdegreesofrecy-cling.Table10.8.2showstheMSWcompositionassumedforsuchastudy.Inthismodel,thepretreatmentstepsin-cludesizereduction(toabout5cm),screening,magneticGradesofRDFseparation,andairclassification.Table10.8.3givestheDifferentgradesofRDFcanbeproducedfromMSW.Generallythehigherthefuelquality,thelowerthefuelTABLE10.8.2COMPOSITIONOFWASTEFORBASEyield.Forexample,anRDFplantinAlbany,NewYork,CASEsimplyshredstheincomingwasteandpassestheshreddedmaterialacrossamagneticseparatortoremovetheferrousPercentcomponent.Thefuelyieldisroughly95%,whiletheav-ComponentAs-ReceivederageBtuvalueofthisfuelissimilartorawMSW.Ferrous5.5Conversely,producingapelletfuelrequiresmuchprepro-Aluminum0.9cessing.Afieldyieldofabout50%,basedonthetotalin-Glass9.5comingwaste,canbeachievedandhasaheatingvalueMixedpaper22.6whichapproximates6500to7000Btu/lb.Newsprint11.8Industry-widespecificationsforRDFdonotexist,butCorrugated12.2RDFhasbeenclassifiedaccordingtothetypeanddegreeNonPVCplastic2.9ofprocessingandtheformoffuelproduced(seeTablePVCplastic0.310.8.1).ThepropertiesofRDFtoconsiderandincorpo-Yardwaste12.5Foodwaste2.5rateintosupplycontractsincludetheproximateanalysisOthernoncombustible9.5(moisturecontent,ashcontent,volatiles,andfixedcar-Othercombustible9.8bon);ultimateanalysis(C,H,N,O,S,andashpercent-age);higherheatingvalue(HHV);andcontentofchlorine,Source:G.M.SavageandL.F.Diaz,1986,Keyissuesconcerningwastepro-fluorine,lead,cadmium,andmercury.cessingdesign,NationalWasteProcessingConference,Denver,1986(ASME).©1999CRCPressLLC TABLE10.8.3CALCULATEDMSWANDRDFPROPERTIESANDCOMPOSITIONSRESULTINGFROMDIFFERENTDEGREESOFRECYCLINGHeatingPercentUltimateAnalysis(Percent)HeavyMetalAnalysis(mg/kg)ValueAshScenario(Btu/lbWet)(Dry)CHONSClSbAsBaCdCrCuPbHgNiZnBaselineCaseMSW397036.632.14.325.80.580.170.33534.9216014.421072063018220290RDF567011.044.35.937.70.440.160.49685.4262014.02001705002304016030%Fe,Al,andGlassMSW420032.034.04.627.70.620.180.36555.1222015.020057060018160270RDF574009.744.96.038.30.450.160.51655.2251013.41901404702203013030%Fe,Al,Glass,Newsprint,andCorrugatedMSW407035.033.34.426.10.700.190.37624.8250016.521060055021170300RDF571011.044.56.037.30.520.170.56825.3320016.22101604402803016030%NewsprintMSW390537.931.64.225.20.610.170.34555.1225015.021075059018230300RDF563511.644.05.937.40.470.160.52745.9286015.12001804502504017050%PVCMSW395036.832.14.325.80.590.170.24524.8219014.421073064018220290RDF565511.144.35.937.80.450.160.34675.3268014.02001705002304016050%YardWasteMSW405537.631.74.225.50.500.160.33555.1223015.022075066018230300RDF572011.044.25.937.80.410.160.49695.5267014.12101705002304016050%FoodWasteMSW399036.732.24.325.80.570.170.32535.0217014.221070063018220270RDF568011.044.35.937.80.440.160.48685.4262013.920016049022040150Source:SavageandDiaz,1986.propertiesoftheMSWandtherecoveredRDFaftervar-reduction,theinfluenceoftheopeningsizesinscreeningiousdegreesofrecycling.equipment,andtheeffectofplacingshreddersupordown-Themodelshowsthattheashcontentdropsandthestreamofthescreeningorair-separationequipment.SomeheatingvaluerisesastheMSWisprocessedintoRDF,andmodelingcalculationscanalsoestimatethebase/acidra-thetypeanddegreeofrecyclinghasonlyalimitedeffecttio,slaggingindex,andfoulingindexvalues,whichcanontheashcontentorheatingvalue(SavageandDiazindicatelikelymaintenanceandoperatingproblemsasso-1986).ThenitrogencontentoftheRDFisconsistentlyciatedwithaparticularprocess.lowerthanthatoftheMSW,andthesulfurcontentisrel-ativelyunaffectedbyprocessing;whilePVCrecyclinghasAdaptedfromMunicipalWasteDisposalinthe1990sasubstantialeffectonthechlorinecontentoftheRDF.byBélaG.Lipták(Chilton,1991).Thecalculatedheavymetalanalysisshowsthatbecauseofthemagneticseparationofferrousmetals,theconcentra-tionoflead(Pb)andzinc(Zn)islowerintheRDFthanReferenceintheMSW.Savage,G.M.andL.F.Diaz.1986.Keyissuesconcerningwastepro-ModelingisausefultoolintheevaluationofRDFcessingdesign.NationalWasteProcessingConference,Denver,1986.processes.OnecanestimatetheeffectofthedegreeofsizeASME.©1999CRCPressLLC TreatmentandDisposal10.9WASTE-TO-ENERGYINCINERATORSIncinerationisthesecondoldestmethodforthedisposalimizepollution.Twoothergoalsarehighplantavailabil-ofwaste—theoldestbeinglandfill.Bydefinition,inciner-ityandlowfacilitymaintenancecost.ationistheconversionofwastematerialtogasproductsandsolidresiduesbytheprocessofcombustion.CombustionunderoptimalconditionscancutMSW90%Mass-BurnandRDFIncineratorsbyvolumeand75%byweight.HotgasesgeneratedasaresultofcombustionexitthefurnaceandpassthroughTwomaintypesofwaste-to-energyincineratorsaremass-boilerswhichrecoverenergyintheformofsteam.ThisburnincineratorsandRDFincinerators.Figure10.9.1steamcanbesolddirectlyorconvertedtoelectricityinashowsthetypicalstructureofawaste-to-energyfacility.turbine.Withdwindlinglandfillspace,incinerationre-Themorecommonmass-burnincineratorsburnMSWducesvolume,butsomescientistscautionthatincineratorasreceivedwithminimalonsiteefforttoseparateobjectsresidueismoredangerousandshouldnotbedisposedofthatdonotburnwellordonotburnatall.(Forexam-inregularlandfills.ple,bulky,oversizeditemssuchastires,bedframes,fences,Thecombustionprocesscarriestheriskofreleasingairandlogsareoftenseparatedbyhandtoavoidproblems,pollutants.Emissionsfromincineratorscanincludetoxicbutglassbottlesandmetalsusuallyarenot.)metalsandtoxicorganics.Theprimarygoalsofwaste-to-RDFincineratorsburnMSWthathasbeenpre-energyincinerationaretomaximizecombustionandmin-processedandsorted(eitheronthesiteoftheincinerator1TippingHall16Stack2RefuseBunker17ControlRoom3GrappleandRefuseCrane18DeaeratorStorageTank4CraneOperatorControlandHeater5ChargingHopper19MotorControlCenter6OverfireAirFan20MaintenanceShop7RamFeed21Heaters8IgnitionBurnerFan22Condenser9UnderfireFan23Switchgear1310RollerGrate24IdFan11AshConveyorsto25TurbineCrane12MaterialsRecovery12Boiler13OverfireAirIntake1514TurbineGenerator3415Precipitator527625241818101917141692120221123FIG.10.9.1Schematicofatypicalwaste-to-energyresourcerecoveryfacility.©1999CRCPressLLC oratseparateprocessingfacilities).Noncombustibleandmationabouttheamountandtypeofwastetheplantisrecyclablematerialsuchasferrousmetals,aluminum,andtoburn(seeSections10.1to10.5)aswellasprojectionsglassareseparatedmechanicallyandcollectedforpro-forfuturesolidwastemanagementpracticesinthecom-cessingandfuturesaleordisposal.Thecombustiblepor-munity.tionisconvertedtoamoreuniform,pelletfuelthroughNext,plannersmustdeterminewhattoburn.Inkeep-particlereduction(usually4-to6-inpellets).ingwiththehierarchyofthePollutionPreventionActRDFtechnologyispreferredbyrecycling-orientedusers(PPA),astate-of-the-artstrategyprovidesforthemaxi-partlyforeconomicreasons(e.g.,incomefromthesaleofmumamountofsourcereductionandrecycling,includingaluminum),andpartlybecauseitcutstheincineratorcomposting,beforeincineration.Furthermore,materialsresiduestolessthanhalfandtherebyreducestheamountthatarenotrecyclableandareunsuitableforburningbe-ofleftovermaterialthatmustbelandfilled.RDF-firedboil-causetheyarenoncombustible,explosive,orcontaintoxicerscanrespondfastertoloadvariations,requirelessex-substancesorpollutantprecursors,shouldbeseparatedcessair,andcanoperateathigherefficiencies.fromthewastetobeburned.Theseactivitiespreservenat-Comparisonsofmass-burnerperformanceonbothrawuralresources,improveincineratorefficiency,andmini-MSWtosimplepreparedfuelsshowthatpreparedfuelmizepollutantemissionsandashquantityandtoxicity.plantshavemanyadvantagesoverthemass-burningtech-Ageneral,overridingprincipleinthedesignofasolidnology(SommerandKenny1984).However,RDFtech-wasteincineratoristousethecorrectsizeincineratorfornologyisstillinthedevelopmentstage.Themajorityoftheamountofanticipatedwaste.Combustionismostef-incineratorsunderconstructionaremass-burn.PartoftheficientwhenanincineratorconsistentlyburnsthequantityreasonforthislackofdevelopmentisthecomplexityofandqualityofMSWitwasconstructedtoburn,asfol-theRDFprocess,whichremainsanexpensiveandmain-lows:tenance-intensivealternativetomass-burning.Iftheplantisoversized(i.e.,iftheamountofMSWavail-ableforburningislessthantheplantwasdesignedtotake),itmayoperatelessthanfulltime.EachstartupPlantDesignandshutdowncausesunsteadyburningconditions,re-Theplantdesignforawaste-to-energyplantshouldcon-sultinginreducedoverallefficiency.Suchunsteadystatesiderstate-of-the-artconceptsaswellasotherdesigncri-conditionsincreasethegenerationofincompletecom-teria.bustionandparticulates.Moreimportantly,aplantthatisoversizedfortheamountofwasteavailabletoburnhashigherpertondisposalcosts.Ifanincineratorisundersized(thatis,moreMSWisavail-CONCEPTOFSTATE-OF-THE-ARTabletobeburnedthanoriginallyplanned),toomuchThetermstate-of-the-artforwaste-to-energyplantsrefersMSWmaybeloadedintothefurnace.Overloadinganto(1)thebesttechnologiesandoperatingpracticesforre-incineratorcanresultinincreasedgenerationofin-ducingtheenvironmentalimpactsoftheseplantsand(2)completecombustionaswellasanincreasedvolumeofthebestregularlyattainableemissionlevelsfromthemforunburnedmatterandash.Also,anundersizedinciner-certainairpollutants.Thestate-of-the-artinwaste-to-en-atorthatisnotoverloadedrequiresadditionalexpen-ergyplantdesignhasbeenimprovingovertime.Overthedituresofalternativemethodsofwastedisposalandre-lastdecade,aslandfillspacehasbecomescarce,interestincycling.incinerationhasbeenrenewed,environmentalconcernsIndeterminingtheamountofMSWbeinggenerated,haveincreased,andregulationshavebecomemorestrin-plannersshouldcollectactualwastedatajustpriortode-gent.signandsizing.WastecompositionstudiesshouldideallyTheEPA’sNewSourcePerformanceStandards(NSPS),samplewastefromdifferentneighborhoodsatdifferentproposedin1989andpromulgatedinFebruary1991,timesoftheweekandyear,asshowninFigure10.3.1.werethefirstregulationstobroadlyandspecificallyad-SomecommunitiesuseaveragewastecompositionfromdresstheperformanceofMSWincinerators.Thenewreg-othertownsorcitiestoestimatetheirownwastecompo-ulationssetstandardsinfourbasicareas:goodcombus-sition.However,thismethodcanbemisleadingsincethetionpractice,emissionlevelsforsixpollutants,monitoringcompositionofMSWchangesnotonlyfromplacetoplacerequirements,andoperatortrainingandcertification.butalsoovertime.Table10.9.1summarizestheseregulations.Informationaboutprojectedpopulationgrowthandfu-turetrendsinthevolumeandcompositionofwasteisjustascriticalascurrentwastedata,especiallysincewasteman-DESIGNBASISagementmethodsarechanging.IncineratorsaretypicallyInthedesignofwaste-to-energyincinerators,thesizeofdesignedforatleastatwenty-yearlifetime,andincinera-theplantisacriticalfactor.Plannersneedaccurateinfor-torarrangementsoftenincludelong-term(fifteen-tothirty-©1999CRCPressLLC TABLE10.9.1KEYFEATURESOFNEWFEDERALMSWINCINERATORREGULATIONS(NSPS),COMPAREDTOINFORMSTATE-OF-THE-ARTSTANDARDSNewSourcePerformanceStandardsINFORMState-of-the-ArtStandardMaterialsSeparationNoneRecyclables,noncombustibles,andwastescontainingtoxicmaterialsorpollutantprecursorsremovedGoodCombustionPracticesCarbonmonoxideemissions:50–150ppm(dependingonfurnacetype)50partspermillionPlant-specificmaximumloadlevelPlant-specificmaximumfluegastemperatureatinlettofinalparticulatecontroldevicePollutantEmissionsLevels(7%O2,drybasis)PARTICULATES0.015gperdrystandardcuft0.010grainsperdrystandardcubicfootDIOXINS/FURANS30nanogramsperdrystandardcum—0.10nanogramsperdrynormalcubicmeter—totaldioxinsandfuransEadontoxicequivalentsSULFURDIOXIDE80%reduction,or30ppm30partspermillion(whicheverislessstringent)HYDROGENCHLORIDE95%reduction,or25ppm25partspermillion(whicheverislessstringent)NITROGENOXIDES180ppm100partspermillionHEAVYMETALSNoindividualstandards;particulateNotdefined;furtherresearchneededtoidentifyemissionsassurrogatelowestregularlyattainableemissionslevelsMonitoringRequirementsCONTINUOUSMONITORINGCarbonmonoxide,opacity,sulfurFurnaceandfluegastemperature,steampressuredioxide,nitrogenoxidesandflow,oxygen,carbonmonoxide,opacity,sulfurdioxide,oxidesofnitrogenANNUALSTACKTESTSParticulates,dioxins,furans,hydrogenchlorideParticulates,dioxins/furans,hydrogenchloride,metalsOperatorTrainingandCertificationAmericanSocietyofMechanicalFormalacademicandpracticaleducation;Engineerscertificationstandardsforsupervisedon-the-jobtraining;chieffacilityoperatorsandshiftsupervisorsformaltesting;periodicreevaluationSource:U.S.EnvironmentalProtectionAgency,1991,Burningofhazardouswasteinboilersandindustrialfurnaces,finalruling,FederalRegister56,no.35(21February),7134–7240.year)contractsforthequantityofMSWtobedeliveredphysicaldesignoftheplant.Forinstance,differentmate-totheplantandforthequantityofenergytobesold.rialsgeneratedifferentamountsofheatenergywhenKnowingwhatpotentiallyrecyclablematerialisintheburned,andknowingtheanticipatedoverallBtuvalueiswastestreamandinwhatquantitiesisessential(seeSectioncriticaltoplanningboilercapacityandfurnacestructure.10.3).ThevariabilityofMSW(specificallydensityduetochangesFinally,plantdesignersneedinformationabouttheincomposition)isanotherdesignconsiderationforvolu-compositionofthewastestreamtodeterminetheoptimalmetricmaterialhandlingequipmentforRDFincinerators.©1999CRCPressLLC ProcessDesignTABLE10.9.2MATERIALSROUTINELYPROHIBITEDBYMASS-BURNINGAtypicalincineratorsystemcontainsbasicelements:afeedPLANTSsystem,acombustionchamber,anexhaustsystem,andaresiduedisposalsystem.AncillaryequipmentincludesBulkywastes(e.g.,furniture)(maybeacceptableifreducedinsize)shreddersandamaterialsorterinthefrontendandairNoncombustiblewastes(notincludingglassbottles,cans,etc.)pollutioncontroldevicesandaheatrecoverydeviceattheExplosivesbackendoftheincinerator.ModernincineratorsintheTreestumpsandlargebranches(maybeacceptableifreducedUnitedStatesusecontinuous-feedsystemsandmovinginsize)gratesinprimarycombustionchamberswhicharelinedLargehouseholdappliances(e.g.,stoves,refrigerators,washingwithrefractorymaterial(heat-resistantsilica-basedmate-machines)rial).SecondarycombustionchambersburnthegasorVehiclesandmajorparts(e.g.,transmissions,rearends,springs,fenders)solidsnotburnedintheprimarycombustionchambersbe-Marinevesselsandmajorpartsforedischargingtotheairpollutioncontroldevices.LargemachineryorequipmentConstruction/demolitiondebrisTiresWASTERECEIVINGANDSTORAGELeadacidandotherbatteriesAshesAstate-of-the-artsolidwastemanagementsystemspeci-Foundrysandfiesexactlywhatwastecanbeburned(basedoncom-CesspoolandsewagesludgebustibilityandcontentofthetoxicmaterialsandpollutantTannerywasteprecursors).Itensuresthatprohibitedmaterialsarede-Watertreatmentresiduestectedandremovedfromthewaste.Table10.9.2compilesCleaningfluidsthematerialsthatareprohibitedatseveralMSWinciner-Crankcaseandothermechanicaloilsators.Inaddition,stringywireitems,suchasfencingandAutomotivewasteoilPaintstrollingwire,canbecomeentangledinconveyorsandAcidsshouldberemovedfromtheMSWfeed.Suchspecifica-Causticstionsarestatedincontractsbetweenoperatorsandmu-Poisonsnicipalities.Plantoperatorsshouldpreventprohibitedma-Drugsterialsfromenteringtheplantorthefurnace.RegulatedhospitalandmedicalwastesApreliminaryviewofthewasteisrecommendedwhenInfectiouswasteincomingMSWtrucksareweighed.Scales,preferablyin-DeadanimalsRadioactivewastetegratedintoanautomatedrecordingsystem,shouldbeStringywire(e.g.,fencingandtrollingwire)providedtorecordtheweightoftheMSWenteringtheplant.Tippingfloors,whichresemblelargewarehouseSource:M.J.Clark,M.Kadt,andD.Saphire,1991,Burninggarbageinthefloors,arebettersuitedforvisualinspectionandthere-US,editedbySibylR.Golden(NewYork:INFORM,Inc.).movalofunwanteditems.State-of-the-artscreeningin-cludesopeninggarbagebagsonthetippingfloortoiden-tifyunwanteditemsinsidethebags.RadioactivitysensorscalculatedbasedonanMSWdensityof350lb/cuydofareusedasscreeningdevicesforhospitalwaste.TheMSWpitvolume.isdischargedfromthetippingfloorintothestoragepitorRefusetendstoflowpoorlyandcanmaintainanangledirectlyintothefurnace.ofreposegreaterthan90°.Thus,plantscommonlystackThestorageprovideddependsonvariationsintheraterefuseinstoragefacilitiestomaximizestoragecapacity.oftruckdeliveryofMSWtotheplantandtheplannedStoragepitsareusuallylong,deep,andnarrow.Apitburningschedule.StoragepermitsMSWtoberetainedcanbelocatedinfrontofthefurnaceorapitcanbesit-duringpeakloadsandthusallowsthecombustioncham-uatedoneachsideofthefurnace.Ifthestoragepitisoverberstobesizedforaloweraveragecapacity.Largestor-25ftinwidth,therefusedumpedfromthetrucksmustageareasaregenerallyrequiredforMSWsinceitisquitegenerallyberehandled.Thefloorofstoragepitsispitchedbulky,withabulkdensitybetween250and350lb/cuydtothefacilities’drainage.Storagepitsareconstructedof(180and240kg/cum).Provisionsareoftenmadeforasreinforcedconcretewithsteelplatesorrailsalongthesides,muchasoneweek’sMSWatsmallincineratorstoallowwhichprotectthemagainstdamagefromthecranebucket.fordowntimeandotheroperatingproblems;twotothreeThepitisusuallyenclosedintheMSWstoragebuilding,daysofMSWstorageismorecommonatlargerplantsinwhichcombustionairforthefurnaceisdrawn.This(lessthan500tn/d).Plannersshouldconsiderseasonablearrangementcreatesaslightvacuuminsidethebuildingandcyclicvariationsandunplannedshutdownsinestab-whichdrawsinatmosphericairandpreventstheescapelishingplantstoragerequirements.Thepitsizeisusuallyofodorsanddust.©1999CRCPressLLC FEEDINGSYSTEMSThewastefeedsystemintroducesrefuseintotheinciner-atorfromthetippingfloororpit(or,incaseofanRDFfuelplant,fromthepreprocessingfacilities).Ofthetwomaintypesofrefusefeedsystems,acontinuousloadingsystemcontributestomoreefficientcombustionthanbatchloadingbecauseitallowsamoreevenflowoffuel.Inbatchloading,thewasteisintroducedbyafront-endloaderthatshovesthegarbage,indiscretebatches,intothefurnace.Thebatchmethodadverselyaffectscombus-tionsinceeachloadpushedintotheincineratorcausesatemporaryoverload,depletingavailableoxygenandcre-atingpoorcombustionconditions.Variationsintempera-tureduetoairleaksintothefurnacehaveanadverseim-pactonrefractorymaterialandincreaseairemissions.InsmallplantswithfloordumpsandstoredMSW,feedingisaccomplishedonasemibatchbasisbyramswhichpushMSWdirectlytothefurnaceat6-to10-mincycles.Withcontinuousloading,atravelingbridgecraneequippedwithagrappledepositswaste,afewtonsatatime,intothetopofaninclinedchute.Thegarbagemovesdownthechuteontothedryingzoneofamovinggrateallowingforcontinuousintroductionofwasteintothefur-FIG.10.9.2Bridgecraneinstallation.nace.RDFistypicallycontinuouslyfedintothefurnace.AbasicrequirementofthecontinuousloadingsystemBothcranetypeshaveeitheraclam-shellgrappleoranistokeepthecharginghoppertothefurnacefiredatallabrasion-resistantsteelbucketwithacapacitybetween30timesandtoprotectagainstburnbacksoffirefromtheand150cuft(1–4cum).Anautomaticlubricationsys-combustionareathroughthechutetothestoragepitarea.temforthecraneisrecommended,andagoodpreventivemaintenanceprogramisessential.Sparebucketsarealsorecommended.Bridges,trolleys,andhoiststravelatspeedsChargingCranesof6ftpersec(100mpermin).ThetravelingbridgeisalsousedtomixtheMSW.TwotypesofcranesarewidelyusedforhandlingrefuseMixingMSWfacilitatescombustionparticularlyifalargeformunicipalincinerators.Themostversatileisthebridgeamountofonetypeofwasteisdischargedintoonepartcranewithaclam-shellbucket.Thebridgeitselftravelsofthestoragepit.Inthepast,thecranewasoperatedfromacrossthelengthofthestoragepitwhileatrolleymovesanair-conditionedcabmountedonthebridge.Within-thebucketoverthelengthofthebridge.Withthebridgecreasingfrequency,craneoperationisbeingcentralizedincrane,thestoragepitcanbeaswideas30ft.Ifthestor-acontrolroom,usuallylocatedatthechargingfloorele-agepitiswide,thecranehastotraveltothefarsideofvationandeitheroverthetippingpositionsoppositethethepittokeeprefusefromaccumulatingthere.Thetimecharginghoppersorclosetothecharginghoppers.requiredtotraversethepitaffectsthecarryingcapacityofthesystemandwidepitswithlongbridgesarenoteco-nomical.Figure10.9.2showsalayoutusingabridgecrane.ChargingHoppersandGatesInlargefurnacesofmorethan300tpdcapacity,bridgeCharginghoppersholdupsomevolumeofrefusetoguar-cranesareused.anteeareasonablyuniformwasteflowintotheincinera-Thesecondtypeofcrane,themonorail,canmoveintor.MSWenterscharginghoppersinthefollowingways:onedirectiononly,alongtherailatthecenterlineofthepit.TherangeofthemonorailislimitedinregardtotheInlargerplantswherethehoppersarelocatedabovethepit.Thepitwidthislimitedtoabout1mwiderthanthestoragepits,MSWisliftedbycranes.widthoftheopenbucket.Ifthestoragepitistoowide,Inlargerplantswherethehoppersandstorageareaareatthebucketcannotmovetothesidesofthepit,andthethesameelevation,MSWistransferredintostoragematerialaccumulatesbecauseofitstendencytoclingto-hoppersbyramfeedersorbyfront-endloaders.gether.Themonorailsystemisnormallydesignedtofol-Inplantsunder100tpdcapacity,MSWisloadeddirectlylowastraightpathwiththepitatoneendandtoliftMSWfromthetrucksintothecharginghoppers.intocharginghoppersattheother.Inamedium100-toInmulticellfurnaces,eachfurnacecellusuallyhasone300-tpdplant,themonorailisoftenused.chargehopper.©1999CRCPressLLC Inacontinuous-charginghopper,theoutletgateiskeptreductiondependslargelyonthedesignofthefurnaceandopen,andtheairsealismaintainedbytheMSWandthetheoperatingpractices.movementofthemechanicalgratechargingthefurnace.Thefollowinggeneralguidelinesfostergoodcombus-Mosthoppershaveanangle-of-slidesurfaceof30to60°tion(Licata1986):fromtheverticaltopreventbridging.ThefeedchuteisThegrateshouldbecoveredwithfuel(auniformdepthnormally4ft(1.2m)wide,topasslargeobjectswithmin-ofgarbageandtrash)acrossitswidth.Thedepthatanyimumbridging,and12to14ft(3.6to4.2m)longfromlocationonthegrateshouldbeconsistentwiththeairthehoppertothefrontendofthefurnace.Becauseofitsthatcanbedeliveredforcombustionatthatpoint.proximitytothecombustionzone,thecontinuous-charg-Theincineratormustincludeanairdistributionsysteminghopperisusuallywatercooled.thatapportionsairaccordingtotheburningrateofThecontinuous-charginghopperallowsbetterfurnacewastealongtheentirelengthandwidthofthegrate.temperaturecontrolandtherebyreducestheneedforre-Underfireairshouldbeintroducedcarefully.Dependingfractorymaintenance.ItalsospreadstheMSWmoreonthetechnology,itcanbeconcentratedinasmallevenlyacrossthegrate,inarelativelyuniformandthinareaorspreadoveralargearea.Zonesofhigh-pres-layer,whilesealingthefurnacefromcoldair.sureairandblowtorcheffectsshouldbeeliminated.LessonslearnedonRFDfacilitiessuggest(1)usingsim-BurstsofairinonesectionofthefuelbedpreventevenpleRDFfloorstorage,notbinsthatcanbecomeplugged;mixingofairintheburningrefuseinotherareas.(2)usingsimpleRDFtransferviaaconveyorratherthanAirmustbeintroducedintoburningrefusebothabovepneumaticsystems;(3)maintainingauniformflowofRDFandbelowtheburningbed.Oxygenprovidedthroughtoboilerfeedersandavoidingslugfeeding,whichresultstheoverfiresystemhelpscompletethecombustionofinunstableboilercontrol;and(4)usingaprovenRDFanyhydrocarbons(andparticulates)notoxidizednearfeeder,whichmaintainsevengratedistributionandisre-thefuelbed.sponsivetoloadchange(GibbsandKreidler1989).Stepsmustbetakentopreventthebuildupofslagwithinthefurnace.SlagcandamagetheboilersystemandalsoresultsinpoorcombustionbypreventingproperairTHEFURNACEmixinginthefuelbed.Thecombustionzonesinarefuseincineratorarecom-Gasesgeneratedintheincinerationprocessshouldexpe-monlyreferredtoasfurnaces.Severalcommondesignsareriencemaximummixingtofacilitateoxygenreachingcurrentlyinuse:single-chamberfurnaces,dual-chamberanyunburnedparticlesandtoprovideamaximumfurnaces,multiple-chamberedfurnaces,rotarycombus-dwellingtimeforthegasesbeforebeingreleasedintotors,andfluidizedcombustors.Themostcommoncon-theatmosphere.figurationincludestherectangularfurnace,themulticellThefluegastemperatureshouldbeatorabove1600°Ffurnace,theverticalcircularfurnace,thecombinedrec-forapproximately1secafterleavingthefirebed.Figuretangularfurnace,andtherotarykiln.Furnacescanalso10.9.3showsthatthesecombustionconditionsdestroybedistinguishedaccordingtothetypeofgratesused.Becausealllargemodernincineratorsarecontinuous,thissectiondiscussesonlycontinuoussystems.Twoclassesofcontinuouslyfeedfurnacesareusedtoday:refractory-linedandwaterwallfurnaces.Waterwallfurnacesrecover100wasteheataswellasreducewastevolume,whilerefrac-Decachlorobiphenyltoryfurnacesareusuallydesignedforvolumereduction.Biphenyl10Waterwallfurnaceshavewater-filledtubesinsteadofre-fractorymaterialliningthecombustionchambers.AsDibenzofuranHexachlorobenzeneburningrefusetransfersheatthroughthewallstothewa-1.0terinthetubes,thesetubesformacoolwallwhichisinafter1secDibenzo-p-dioxincontactwiththeflameandhotgas.Thesecoolerwallspre-0.1venttheaccumulationofslagonthesideofthecombus-WeightPercentRemainingtionchamberandproducesteam.0.00505006007008009001000˚C3210010001200140016001800˚FCombustionProcessExposureEfficientandevencombustionisakeyfactorinminimiz-FIG.10.9.3Destructionefficienciesofvariouscompoundsasingtheenvironmentalimpactofwaste-to-energyinciner-afunctionoftemperature.(Reprinted,withpermission,fromAirators,reducingboththeamountofunburnedmaterialinpollutioncontrolatresourcerecoveryfacilities,1984,Californiatheashproducedandtheamountofairemissions.ThisAirResourcesBoard[24May].)©1999CRCPressLLC morethan99.9%ofmanyeffluentcompounds,includingTechnicaldesignincluding:dioxinsandfurans.Excessivelyhightemperaturesandex-—Preventionofreignitiontremevariationscausecrackingandspalling,withrapid—Positiveconveyanceoftherefusemassdeteriorationofrefractories.Theminimumburningtem-—Serviceabilityandreplaceabilityofworn-outpartsperatureforcarbonaceouswastetoavoidthereleaseof—Propermeasuringandcontrolsystemssmokeis1500°F(816°C).Atemperaturelessthan1500°Fpermitsthereleaseofdioxinsandfurans.GrateSystemsAuxiliaryburnerscanbeaddedtomaintaincombus-tionefficiency.ReductionsincombustionefficiencyareThekeyfactorsforhot,uniformcombustionarethecon-usuallyduetooneormorefactors:startupandshutdown;stantmixingofairintothematerialbeingburnedandthelargechangesinmoisturecontent,heatcontent,ortheuseofpartiallycombustedmaterialtoheatandignitenewquantityofincomingrefuse;andmaladjustmentoftheairmaterialintroducedintothecombustionchamber.Threeadjustmentsystem.Auxiliaryburnersburnanother,moremajorEuropeangratedesignshaveworld-wideapplica-uniformfuel(suchasnaturalgasoroil).Theseburnerstion:areusedwhenfurnacetemperaturevaluesfallbelowMartinprocess(seeFigure10.9.4).Inthisdesign,thegrate1600°F,therebystabilizingcombustionbymaintainingahasareversereciprocalaction;itmovesalternatelyminimumfurnacetemperature.Operatorscanincreaseres-downandbacktoprovidecontinuousmotionoftheidencetimebyreducingtheamountofcombustionair.refuse.Thenetmotionoftherefuseisdownwardto-Thedesignofthefurnaceinterioraffectscombustionwardthebottomofthefurnace,buttheagitationcausedefficiency.Carefullyplacedprotrusionsfromthefurnacebyoscillationofthegratecausesconsiderablemixingwall,calledarchesorbullnoses,canredirecttheflowofoftheburningrefusewiththenewlyintroducedmate-airfromthegrate,guidingitintoturbulenteddieswithinrialleadingtorapidignitionanduniformburning.thefurnace.EddycurrentsmaximizeturbulenceduringtheVanRollprocess(seeFigure10.9.5).Thisdesignhasthreecombustionofgases.sections:thefirstdriesthenewlyintroducedrefuseandignitesit,thesecondservesasaprimarycombustionGrateDesignsgrate,andthelastreducestherefusetoash.Grateele-mentsmovesothatatagiventimeforanypairofel-Thegrate(stoker)servesdualfunctions:ements,oneismovingandoneisstationary.This1.Transportsthesolidwasteandresiduethroughthefur-processresultsintherefusemovingtowardthebottomnacetothepointofresiduedischarge.Thegrateshouldofthefurnace,buttheshufflingactionofthegratesag-becoveredwithauniformdepthofMSWacrossitsitatesthefuelbedenhancingthecombustionprocess.width.VKWorDusseldorfprocess(seeFigure10.9.6).Thisgrate2.Promotescombustionbyprovidingproperwasteagi-iscomprisedofseveralhorizontaldrumswithadiam-tationandbypermittingthepassageofunderfireaireterof1.5m(5ft).Theshaftsofthedrumsareparal-throughthefuelbed.However,theagitationshouldnotleloneaftertheotherata30°slope.Thedrumsarebesoviolentthatitcontributestoexcessiveparticulateplacedon1.75-m(about7-ft)centers.Eachdrumisemissions.builtofbars(castiron)intheformofarchedsegmentsThedesignofthegratesysteminthefurnaceisacrit-icalelementintheoperationofaRDFfacility.EberhardtWasteFeed(1966)proposestenelementstoconsiderinthechoiceofHopper,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,agratesystem:Gas,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Theadaptabilityofthecombustionprocesstohandlewide,,,,,,,,,,,,,,,,,,,,,Waste,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,variationsinradiationeffectsFeeder,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Theadaptabilityoftherefractorytohandlewidevaria-Moving,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Bars,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,tionsinradiationeffects,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,CombustionGrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,ProvisionsforcontrollingairquantityandtemperatureFixed,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Extractor,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Bars,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Provisionsforanadjustableretentiontimebasedonthe,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,materialbeingburned,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Anadjustableheightofthewastelayertobeburned,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Acontrollable,stabilizingheatsupply(auxiliaryfuel),,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Air,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Acontrolledcoolingofresidue(byquenching),,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Acontrolledfluegastemperaturepriortoimpingingon,,,,,,,,,,,,,,AshtheradiationheatingsurfaceFIG.10.9.4GratesystemforMartinresourcerecoveryincin-Thecapabilityofobservingthefirelayerandthefiregaseserator.©1999CRCPressLLC WasteFeedwhicharekeyedtoacentralelementbelow.EachdrumHopperrestsoveraseparatechambertocontrolunderfireair.Theunitrotatesinthedischargedirectionatanad-,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,justableperipheralspeedwhichvariesaccordingtothe,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,constituentsofthewastebeingburned.Thedrumshafts,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Dryingand,,,,,,,lieinthebearingsplacedintheoutsidewallsoftheunit,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Gas,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,IgnitionGrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,andeachrollerisfittedwithadrivinggearandcanbe,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,regulatedindependentlyoftheothers.Ignitiongratesat,,,,,,,Main,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Combustion,,,,,,,,,,,,,,,,,thefrontendoftheincineratorgenerallyrotateatup,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Grate,,,,,,,,to15m/hr(50ft/hr).Theburnoutgratesnormallyro-,,,,,,,tateat5m/hr(about16ft/hr)sincetheyhavelittlewaste,,,,,,,,,,,,Air,,,,materialtomove.Theroomunderthegrateisdivided,,,,,,,,,,,,,,,,,,,intoazoneforeachroller,towhichpreheatedorcooled,,,,Air,,,,,,,,,,,fluegas(about200to256°C)canbebrought.Aspe-AlternatingFixed,,,,,,,andMovingElements,,,cialfeedingarrangementcarriestherefusefromtheBurnoutGrateAirfeedingchutetothegrate.FIG.10.9.5VanRollgratesystemforresourcerecoveryin-cinerator.Anotheraspectofgratedesignisthepercentageofairopeningsprovidedinthegrate.TheseairopeningsvaryFIG.10.9.6VKMorDusseldorfprocess(withinstallationoftransversemanifoldfor260secondaryairnozzlesoverrollergrateatWuppertal,Germany).©1999CRCPressLLC from2toover30%ofthegratearea(Velzy1968).tothemaximumchargingrateF(lb/hr)andinverselypro-Proponentsofthelargeropeningsfeelthatthesiftings(theportionaltoFa,thegrateareaA,asfollows:ashfromthefuelbed)shouldbeallowedtofallbelowtheA5F/Fa10.9(1)grateassoonaspossibleandlargeamountsofairshouldbepermittedtopassthroughthebedtomeetthecom-Thegratedesignmustalsobebasedonthemanufac-bustionrequirementsofvaryingfuelcharacteristics.turer’sdesigncriteria.Basically,theonlyconsistentdesignProponentsofthesmalleropeningsciteadvantagessuchcriteriausedbymanufacturersisthespecifiedkilogramasthesmallvolumeofsiftings,thesmallamountofun-(pounds)ofwastethatcanbeloadedpersquaremeterderfireairthatisrequired,andtheresultingshortercom-(squarefoot)ofthegratearea.Plannersneedmoreem-bustionflames,allofwhichreduceparticleentrainmentinpiricaldataforproperdesignandmustdevelopamoretheescapinggas(Velzy1968).rationalapproachtoselectthepropergrate.InatechniqueemployedatsomeU.S.facilities,wasteispneumaticallyinjectedintothefurnacesystemandFurnaceSizingburnedwhilesuspendedinthefurnacechamber,ratherthanbeingburnedonagrate(seeFigure10.9.7).WiththeThefiringfurnacecapacityisafunctionofitsgratearearemovalofferrousmetalsandothernoncombustiblesinandvolume.ThefurnacevolumeisusuallydeterminedontypicalRDFsystems,aboilersystemhasevolvedandhasthebasisofanhourlyheatreleaseof20,000Btu/cuft.IfbeenincommercialoperationatBiddeford,Maine,sincethehourlyreleaserateis20,000Btu/cuftandtheheating1987.Thecontrolledcombustionzone(CCZ)boilerde-valueoftheMSWis5000Btu/lb,thehourlyfiringrateissignisastate-of-the-artboilerdesignforbothwoodand4lb/cuftoffurnacevolume.AtypicaldesignbasisistoRDFboilers(GibbsandKreidler1989).provide30to35cuftoffurnacevolumeforeachtpdofincineratorcapacity(VelzyandHechlinger1987).GrateSizingAirRequirementsThehourlyburningrate(Fa)variesfrom60to90lbofMSWpersqftofgratearea(VelzyandHechlinger1987).Thebasicrequirementofanycombustionsystemisasuf-Anhourlyrateof60lb/sqftreducesrefractorymainte-ficientsupplyofairtocompletelyoxidizethefeedmater-nanceandprovidesasafetymargin.Incoalburningfur-ial.Thefollowingchemicalandthermodynamicproper-naces,thegratesareusuallycoveredtoadepthof6in,tiesmustbeconsideredinincineratordesign:theelementalwhichcorrespondstoanhourlycoalloadof30to40lb/sqcomposition,thenetheatingvalue,andanyspecialprop-ft.TheheatingvaluesanddensitiesofuncompactedMSWertiesofthewastethatcaninterferewithincineratorop-arelessthanhalfofthat.Thus,thesamefiringdensitieseration.Thestoichiometric,ortheoretical,airrequirement(onaBtubasis)producedbycoalcanbeproducedbyiscalculatedfromthechemicalcompositionofthefeedMSWwhentheMSWissuppliedatanhourlyrateof60material.Plannersmustknowthepercentagesofcarbon,lb/sqftandcoversthegratetoadepthof3to4ft.Thehydrogen,nitrogen,sulfur,andhalogensinthewasteasrequiredgrateareainsquarefeetisdirectlyproportionalwellasitsmoisturecontenttocalculatethestoichiometricRDFTravelingGrateStokerCCZLowerFurnaceWithOverbedFeed,,RDFFeedSystemOverfireAirRDFInlets,,MainFeedHopper,,,,,,,,,,LowerRDFHopper,,,,,,,,RefuseDistributors,,,,,UndergrateAirabcFIG.10.9.7RDFfurnace.(Reprinted,withpermission,fromD.R.GibbsandL.A.Kreidler,1989,WhatRDFhasevolvedinto,WasteAge[April].)©1999CRCPressLLC combustionairrequirementsandpredictcombustionaira5theinertandashfractionoftheMSWflowandfluegascomposition.M5themoisturefractionoftheMSWTable10.9.3showsthestoichiometricoxygenrequire-S5thecubicfeetofstoichiometriccoldairrequiredmentsandcombustionproductyieldforeachwastecom-perBtuofheatreleaseponent.Thestoichiometricairrequirementisdeterminede5theexcessairfractiondirectlyfromthestoichiometricoxygenrequirementwithIncaseswheremetalsarenotburnedandcombustiblesuseoftheweightfractionofoxygeninair.Giventem-arepredominantlyorganic,thevalueofSisapproximatelyperatureandpressure,therequiredvolumeofaircanbe0.01(i.e.,1cuftofcoldairper100Btu).Thisapproxi-calculatedbasedongaslaws.mationisvalid,generallytowithin10to20%,forawideIfperfectmixingcouldbeobtainedandwasteburnoutrangeoforganicfuel.Consequently,variationsbetweenoccurredinstantaneously,onlythestoichiometricrequire-wastesdependlargelyontheirnoncombustiblecontent(amentofairwouldbeneeded.However,neitherofthese1M),particularlyastheDIFcalorificvaluesliewithinphenomenaoccursinreal-worldapplications.Therefore,thenarrowrangeof8000to10,000Btu/lb.Thestoichio-someexcessairisrequiredtoensureadequatewaste–airmetricairrequirementsofmostDIFwastearethereforecontact.Excessairisusuallyexpressedasapercentageof80to100cuft/lbor6.4to8lbofairperpoundofwaste.thestoichiometricairrequirement.Forexample,50%ex-Ifthewastecontains50%ashandmoisture,thecalorificcessairimpliesthatthetotalairsupplytotheincineratorvaluesdropto4000to5000Btu/lb.Ifthiswasteisfiredis50%higherthanthestoichiometricrequirement.at150%excess,theairrequirementsare8to10lbofairIngeneral,theminimumexcessairrequirementforanperpoundofwasteasfired.incineratordependsonthedegreeofmixingachievedandInmodern,mechanical,gratefurnacechambers,theun-waste-specificfactors.Mostincineratorsrequire80toderfireandoverfireairareusuallyprovidedbyseparate100%excessairtoburnallorganicsintheMSW(Whelessblowersystems.UnderfireairisadmittedtothefurnaceandSelna1986).Incineratoroperationisoptimizedwhenunderthegratesandthroughthefuelbed.Itsuppliespri-sufficientoxygenisprovidedtoachievecompletecom-maryairforthecombustionprocessandalsocoolsthebustion,butnomore.Additionaloxygenreducesthermalgrates.Underfireairisusuallymorethanhalfofthetotalefficiencyandincreasesnitrogenoxidegeneration.air(50to70%).ParticulateemissionsfromincineratorsThecoldairvolumerequiredforpropercombustionintendtoincreasewithheatreleaseandunderfireairflow,theincineratorperunitweightofMSWcanbecalculatedwhiletheytendtodecreasewithincreasingfuelparticleasfollows(Essenhigh1974):size(seeFigure10.9.8).TotalColdAirVolume(cuft/lb)5B(12a2M)(S)(11e)Overfireaircanbeintroducedattwolevels:10.9(2)Immediatelyabovethefuelbedtopromoteturbulenceandwhere:mixingandtocompletethecombustionofvolatilegasesB5thedryandinert-free(DIF)heatingvalue,inBtu/lbdrivenoffthebedofburningsolidwaste.ofMSWFromrowsofnozzlesplacedhighonthefurnacewall.Thesenozzlesallowsecondaryoverfireairtobeintro-TABLE10.9.3STOICHIOMETRICOXYGENducedintothefurnacetopromoteadditionalturbu-REQUIREMENTSANDCOMBUSTIONlenceofgasesandcontroltemperature.Thenumber,PRODUCTYIELDSsize,andlocationoftheoverfireinletportsdeterminetheamountofturbulenceandbackmixinginthestirredElementalStoichiometricreactionregionabovetheburningwaste.SeeFigureWasteOxygenCombustion10.9.6.Forgoodcombustion,theoverfireairsystemComponentRequirementProductYieldmusthavebroadflexibilitytoaccommodatechangesinC2.67lb/lbC3.67lbCO2/lbCfuelmoisture,ashcontent,andBtuvalue.H28.0lb/lbH29.0lbH2O/lbH2O221.0lb/lbO2—OperatorscontrolfluetemperatureandsmokingbyCl220.23lb/lbCl21.03lbHCl/lbCl2modulatingthetotalairflowandtheunderfire-to-overfire20.25lbH2O/lbCl2airratio.FormostU.S.gratedesigns,therequiredunder-F220.42lb/lbF21.05lb/HF/lbF2fireairpressureisabout3inofwater.Theoverfireair20.47lbH2O/lbF2pressureisadjustedsothatentrancevelocitiesatthenoz-Br2—1.0lbBr2/lbBr2zlearehighenoughtoguaranteehighturbulencewithoutI2—1.0lbI2/lbI2impingingontheoppositewallandresidencetimesareS1.0lb/lbS2.0lbSO2/lbSlongenoughtoassurecompletecombustion.P1.29lb/lbP2.29lbP2O2/lbPInfluentairisusuallyatanambienttemperature,nor-AirN2—3.31lbN2/lb(O2)stoichmally27°C(80°F).Itcangetashighas1650°C(2100toStoichiometricair4.31lbAir/lbO2(stoich)2500°F)intheimmediateproximityoftheflame.Whenrequirementthegasleavesthecombustionchamber,thetemperature©1999CRCPressLLC FIG.10.9.8Effectsofcombustionrate,underfireair,andfuelparticlesizeonparticulateemissionsgeneratedbycombustionofwoodwaste.(Reprinted,withpermission,fromK.L.Tuttle,1986,Combustiongeneratedpar-ticulateemissions,NationalWasteProcessingConference,Denver,1986[ASME].)shouldbereducedtobetween760and1000°C(1400to1800°F).Ifairpollutioncontroldevicesareinstalled,in-duceddraftfansmustbeinstalled,andthetemperatureshouldprobablynotexceed260to370°C(500to700°F).ThemathematicalmodelingoftheincineratorpresentedbyEssenhigh(1974)providesabetterunderstandingofthecombustionprocessestakingplaceinincinerators.Figure10.9.9describesthegas-phase(II)andsolid-phase(I)zonesinatop-chargedincinerator(overbedfeed).CalculatingHeatGenerationCalculatingtheamountofheatgeneratedthroughthein-cinerationofMSWisnecessarytodeterminehowmuchauxiliaryfuelisneededforcombustion.Themoisturecon-tentofMSWrangesfrom20to50%byweight,andthecombustiblecontentis25to70%byweight.TheheatingvalueofMSWdependsonitscomposition.Assumingthattheaverageheatingvalueofthecom-bustibleis8500Btu/lbandthemoistureandinertcon-centrationoftheMSWisknown,environmentalengineerscanestimatetheheatcontentofMSWusingFigureFIG.10.9.9Incineratorforcontinuousoverbedfeedofwaste.10.9.10.IftheheatingvalueofthecombustiblesislessSchematicrepresentssolidbed,zoneI,withoverbed,zoneII.Forthan8500Btu/lb,thenumberinFigure10.9.10mustbeoverbedfeed,zoneIhassubzones,includingI(A),thecombus-multipliedbytheratiooftheactualheatingvaluedividedtionandgasificationsectiononthegrate,andI(B),thedryingby8500.andpyrolysisaboveI(A).ZoneII(overbedcombustion)hasaTable10.9.4givesamaterialbalanceofburning100backmix(stirred)regioncalledsubzoneII(A),followedbyapluglbofMSW.ThetableassumestheMSWtohaveaheatflowburnoutregion,subzoneII(B).Withunderfeed,zoneIisin-contentof5000Btu/lb,amoisturecontentof22.4%,andverted,withdryingandpyrolysisbelowthecombustionsubzoneanoncombustiblecontentof19%andthatitcontains28andthereactionfrontmovingdowninsteadofupasshown.©1999CRCPressLLC Anenthalpy-balancecalculationforthisexampleshowsthattheenthalpyofeachpoundofexistinggasis455Btuhigherthantheenthalpyofthe80°Fairthatenters(VelzyandHechlinger1987).Basedonthisenthalpyrise,theex-pectedfluegastemperatureof1680°FcanbereadfromFigure10.9.11.Thisfluegastemperatureislowenoughtoprotecttherefractory.HEATRECOVERYINCINERATORS(HRIs)ThreetypesofHRIdesignsareusedtoburnMSW:mass-burninginrefractory-walledfurnaces,mass-burninginwa-terwallfurnaces,andcombustionofRDFinutilityboil-ers.FIG.10.9.10Moisture–heatcontentrelationwith8500Btu/lbcombustiblematerial.(Reprinted,withpermission,fromVelzyMass-BurninginRefractory-WalledandHechlinger1987.)FurnacesInmass-burninginrefractory-walledfurnaces,thewaste-lbofcarbonand0.6lbofhydrogen.Italsoassumesthatheatboiler,locateddownstreamofthefurnace,receives1–3lbofcombustiblesescapeunburned,and140%ex-heatfromthefluegases.OlderHRIstendtoberefrac-cessairisneededtocooltherefractories.Therefore,thetory-walleddesigns,andtheirsteamproductionisusuallytotalairrequiredis2.4timesthestoichiometricrequire-limitedto1.5to1.8lbofsteamperpoundofMSWment,or8.24lbofairperpoundofMSW.burned,assumingthattheheatingvalueofMSWis4400Btu/lb.Inolderfurnaces,thelargerthefurnace,thelowerthesurface-to-volumeratio,becauselesssurfaceexiststoTABLE10.9.4MATERIALBALANCEFORFURNACEcooltheflame.Theseunitsneedhigherquantitiesofcom-(INLB/100LBOFREFUSE)bustionairtopreventoverheatingthewall,whichresultsinslagginganddeterioration.Approximately50to60%Input:Refuseoftheheatgeneratedinthecombustionprocesscanbere-Combustiblematerialcoveredfromsuchsystems.Cellulose52.74Oils,fats,etc.5.8658.6Moisture22.4Noncombustible19.0100.0Totalair,at140%excessairOxygen191.0Nitrogen633.0824.0Moistureinair11.0Residuequenchwater5.0Total940.0Output:CO2(2833.667)102.7Air—Oxygen(191–80)111.0Nitrogen633.0744.0MoistureInrefuse22.4Fromburningcellulose29.3Fromburninghydrogen5.4Inair11.0Inresiduequenchwater5.073.1Noncombustiblematerial19.0Unaccountedfor1.2Total940.0Source:C.O.VelzyandR.S.Hechlinger,1987,Incineration,Section7.4inMark’sstandardhandbookformechanicalengineers,9thed.,editedbyT.FIG.10.9.11Enthalpyoffluegasabove80°F.(Reprinted,BaumeisterandE.A.Avallone(NewYork:McGraw-Hill).withpermission,fromVelzyandHechlinger1987.)©1999CRCPressLLC Mass-BurninginWaterwallFurnacesCombustionofRDFinUtilityBoilersInmass-burninginwaterwallfurnaces,mostorpartoftheIncombustionofRDFinutilityboilers,theRDFisoftenrefractoryinthefurnacechamberisreplacedbywater-burnedinapartiallysuspendedstate,wheresomeofthewallsmadeofcloselyspacedsteeltubesweldedtogetherRFDstaysonthegrate.Steamproductionisabout3lboftoformacontinuouswall.Wateriscontinuouslycircu-steamperpoundofRDF.TheefficiencyofRDFboilerlatedthroughthesetubes.Innewerwaterwalldesigns,theunitsrangesfrom65to75%.steamproductionisaround3lbofsteamperpoundofMSW.TheincreaseinthermalefficiencyismostlyduetoMinimizingSuperheaterCorrosionareductionintheexcessair(fromabout150%forre-fractory-walledfurnacestoabout80%forwaterwallfur-Togenerateelectricityfromsteamefficiently,HRIsmustnaces).heatthesteamtoatleast700°F(371°C).Thistempera-Coatingasubstantialheightoftheprimarycombus-tureresultsinmorefiresidecorrosioninMSW-firedboil-tionchamber,whichissubjecttohighertemperaturesersthaninregularboilers.Corrosioninrefuseboilersisandflameimpingment,withathincoatofsiliconcar-relatedtothehighchloridesinMSW.WhileanRDFpro-biderefractorymaterialandlimitingtheaveragegasve-cessingsystemcanremovesomeofthematerialcontain-locitiestounder15ft/sec(4.5m/sec)isrecommended.ingchlorides,removingchloride-containingmaterialintheGasvelocitiesenteringtheboilerconvectionbankshouldRDFprocessingsystemisnotarealisticmeanstopreventbelessthan30ft/sec(9.0m/sec)(Velzy1986).Theeffi-boilercorrosion.High-nickel-alloysuperheatertubes(e.g.,ciencyofheatrecoveryinsuchunitsrangesfrom65toInconel825)minimizesuperheatercorrosioninaddition70%.toprotectingthefurnacefromoverloadingandprovidingFIG.10.9.12Mountingtubesverticallyinahorizontalsuperheatersectiontopreventparticlevelocityincreases.(Reprinted,withpermission,fromA.J.Licata,R.W.Herbert,andU.Kaiser,1988,Designconceptstominimizesuperheatercorrosioninmunicipalwastecombustors,NationalWasteProcessingConference,Philadelphia,1988[NewYork:ASME].)©1999CRCPressLLC FIG.10.9.13Boilerdesigncriteriaforcorrosionanderosioncontrol.(Reprinted,withpermission,fromLicata,Herbert,andKaiser1988.)FIG.10.9.14Rapperboilersuperheaterheaders.(Reprinted,withpermission,fromLicata,Herbert,andKaiser1988.)ruggedfurnacewalls.Hydrogenchloridecorrosionbeginsbuildupoccurs.Figures10.9.12and10.9.13showtherec-bypenetratingaslaglayeronthesuperheatertubes.Theommendedsuperheaterdesigncriteriaforvelocitiesandtubesmustbekeptcleanbysootblowersormechanicaltemperatures.rapping.ChloridesinhotgasesbecomecorrosiveandcanAnotherdesignimprovementistheeliminationofthedestroyasuperheater.harmfuleffectsofsoot-blowingbysteamorairwhichdam-Withimprovedsuperheaterdesigns,theoperatingsu-agestheprotectiveoxidefilm,createshotspotsfromperheatertemperaturecanbeincreasedfrom750to825nonuniformcleaning,andreentrainsashintothefluegas.or900°F(Licata,Herbert,andKaiser1988).Thistem-Rappingratherthanblowingcaneliminatetheseeffectsperaturecanbeachievedwhengasvelocitiesarekeptbe-(Licata,Herbert,andKaiser1988).Figure10.9.14showstween15and18ft/sectominimizetheerosioncausedbypneumaticallyactuatedmechanicalrappersthatallowde-theimpactoftheparticles.Inaddition,tubesshouldbepositstoslidedownthetubesurfacesintothehoppersbe-liberallyspacedtomitigatetheincreaseinvelocityasashlow.©1999CRCPressLLC Theboilerdesignshouldalsoprotectagainststratifica-rangeof6to9pH.Thewatercanalsocontainhighcon-tion(whichcanresultinreducedatmospherequality)bycentrationsofBOD,dioxins,heavymetals,andothersus-forcingtheflue-gasstreamtomakea180°turnbeforeen-pendedordissolvedtoxicorpollutingconstituents.Forteringthesuperheater(seeFigure10.9.12).Whentheex-thisreason,theash-handlingsystemmustoperateinthecessairlevelismaintainedat80to85%,highlevelsofzerodischargemode(StelianandGreene1986).AwaterCOconcentrationcausedbyincompletecombustioncancirculationandclarificationsystem,includingproperlyde-beprevented.Anotherrecommendedfeatureisaceramicsignedbasins,sumps,andaneasilymaintainedpumpingliningforthepostcombustionzone.Thisliningprovidesastation,isrequired.Tocapturethewaterthatmightdrain1-sec(minimum)residencetimeforfluegasesattemper-offintheash-transferprocess,thesystemshouldhaveaturesinexcessof1800°F(980°C)beforetheyenterthecatchtroughswheretheconveyortransferstheashintosuperheatersection.thereceiver.AnincreasedsootremovalfrequencyandinnovativeIncoldregionswithfreezingwintertemperatures,thecleaningtechniquescanminimizethesecondaryformationash-handlingsystemmustbeprotectedagainstfreezing.Inofdioxinsandfurans.Cleanertubeshavefewerflyashcoldareas,heatedtruckstransporttheash,andthefly-ashparticlesonwhichdioxinsandfuranscanformandallowconveyorsareinsulatedforprotectionagainstcorrosionmoreheattobetransferredawayfromfluegases.Thisandcaking.Theashconveyorcanunloadwetresidueintoheattransferfurthercoolsthegasesbelowthe450°Fatemporarycontainerordirectlyintoatransportvehicle(250°C),whichisconducivetodioxinandfuranforma-forremovalfromthesite.Inmass-burnsystems,directlytion.Additionally,minimizingtheproductionofprecur-dischargingintodumptrucksisbestandsimplest.sorsinthefurnacebymaximizingcombustionefficiencyhelpsdecreasesecondarydioxinandfuranformation.AIRPOLLUTIONCONTROL(APC)RESIDUEHANDLINGAlthoughincineratordesign,operatingpractices,andfuelcleaning(wastereductionandseparationsystems)cansig-Inacontinuouslyfedincinerator,theashorresidueisdis-nificantlyreducetheamountofpollutantsproducedinchargedcontinuouslythroughachuteintoaconveyorwaste-to-energyplants,somepollutantsareinevitablygen-trough,whichisfilledwithwatertocooltheresiduebe-erated.Add-onemissioncontroldevicesneutralize,con-foreitishauledawayforfinaldisposal.Thechuteissub-dense,orcollectthesepollutantsandpreventthemfrommergedunderquenchwatertosealthefurnaceoutletandbeingemittedintotheair.Mostofthesedevicesareplacedprevententryofatmosphericair.Innewer,mass-burningatthebackendoftheincinerator,treatingfluegasesaf-facilities,full-sizedischargechutesminimizehangupswithtertheypassoutoftheboiler.largepiecesofresidue.DifferenttypesofpollutantsrequiredifferentcontrolTheresidueconveyorpullsthesettledresiduefromthedevices:scrubbersandcondensersforacidgases,scrub-bottomofthetroughandtransportsittoanashhopper,bersandcondenserswithelectrostaticprecipitators(ESPs)storagebin,roll-offcarrier,ordumptruck.Thetroughisorfabricfilters(baghouses)forparticulatesandotherconstructedofsteelorconcrete,andtheresidue–dischargeheavymetalsandchemicalneutralizationsystemsforox-systemusuallyhastwoconveyortroughssothatafullidesofnitrogen(seeSections5.18–22).Variationsexiststandbyisavailable.Havingafullstandbypermitsswitch-withinthesebasiccategories;whilesomedevicesaremoreingbetweensystemsforevenwearandscheduledmainte-likelythanotherstoachievehighremovalefficiencies,op-nance.erationalfactors,suchastemperature,playakeyrole.Astheconveyorcarriestheresidue,mostofthequenchwaterrunsoffandreturnstothetrough.Theconveyorshouldrunatvelocitiesnotexceeding5to10ft/min(1.5Acids,Mercury,Dioxin,andFuranto3m/min)forgooddewateringandminimalwearEmissions(StelianandGreene1986).Themoisturecontentoftheashisusually25to40%ormorebyweight.ReducingtheScrubbers,followedbyanefficientparticulatecontrolde-watercontentoftheashminimizestransportationcostsvice,arethestate-of-the-artequipmentforcontrollingandwaterpollution.Byreducingthespeedofvariableemissionsofacidssuchashydrogenchloride,sulfurdiox-speedconveyors,operatorscanachievethisreductionbyide,andsulfuricacid.Scrubbersgenerallyuseimpaction,maximizingtheresidencetimeofresidueonthewet-dragcondensation,andacid–basereactionstocaptureacidconveyor.Wet-dragconveyorscanoperateatslopesuptogasesinfluegas.Sincegreaterremovalefficienciesusually45°,butsomeoperatorspreferlowerslopestoprotectaccompanygreatercondensation,devicesthatlowergasbulkyitemsfromrollingback.temperaturesandthusincreasecondensationcanenhanceThedesignofaresidue-handlingsystemshouldmini-scrubbereffectiveness.Thelowertemperaturesalsoallowmizethedischargeofwaterpollutants.Ashcanbeacidormercury,dioxins,andfuranstocondensesothattheycanalkaline;therefore,thewaterpHmustbecontrolledinthesubsequentlybecapturedbyaparticulatedevice.©1999CRCPressLLC Threetypesofscrubbersareinuse:wetscrubbers,lemswithwetscrubbers;however,watertreatmentandspray-dryscrubbers,anddryinjectionscrubbers.Thefirstheavymetalprecipitationandevaporationarepromisingtwoscrubbersarecondensers,whiledryinjectionscrub-solutions.Typically,aGermanAPCsystemusesapackedbersrequireaseparatecondenser(eitherahumidifieroratowertoremovehydrogenchloride,sulfurdioxide,andheatexchanger).Inallcases,temperatureand,fordryandcondensedheavymetalsandahigh-efficiencyESPtore-spray-dryscrubbers,theamountoflime(analkalinesub-movedust.stancethatneutralizesacids)arethekeyfactorsaffectingscrubbereffectiveness.Ingeneral,tomaximizeemissionParticulateandHeavyMetalEmissionscontrol,thescrubbershouldbeadequatelysized,operateattemperaturesbelow270°F,andallowfluegascircula-Theemissionsofparticulatesandheavymetalsarebestre-tionthroughthescrubberforatleast10–15sec.ducedbycollectingtheminoneoftwobasictypesofadd-onparticulatecontroldevices:fabricfiltersandESPs(seeWETSCRUBBERSSection5.20).HeavymetalsarecapturedbecausetheyareWetscrubberscaptureacidgasmoleculesontowatercondensedoutoffluegasontotheparticles.Thesedevicesdroplets;sometimesalkalineagentsareaddedinsmallaredesignedtooperateattemperatureslowerthan450°Famountstoaidinthereaction(seeSection5.21).Newde-forfluegasleavingtheboiler;someoperateattempera-signsreportonremovingover99%ofthehydrogenchlo-turesaslowas250°F,whichisbeneficialforcondensingrideand,insomecases,sulfurdioxideandover80%ofandcollectingacids,volatilemetals,andorganics.Thethedioxin,thelead,andmercury(Hershkowitz1986).Thestate-of-the-artlevelforparticulateemissionis0.010gperdisadvantagesincludetheaddedcosttotreatthewaste-drycuft.waterproduced,corrosionofthemetalparts,andincom-patibilitywiththefabrictypeoftheparticulatecontrolde-FABRICFILTERSvice.However,wetscrubberscollectgasesaswellasFabricfilters(alsocalledbaghouses)areastate-of-the-artparticulates,especiallystickyones.particulatecontroltechnologywithaconsistent99%re-movalefficiencyovertherangeofparticulatesizes.FigureSPRAY-DRYORSEMI-DRYSCRUBBERS10.9.15showsaschematicdiagramofascrubberfollowedWiththesescrubbers,acidgasesarecapturedbyimpactionbyabaghouseforparticulatecontrol.Particulatesassmalloftheacidgasmoleculesontoanalkalineslurry,suchasas0.1micronscanbecaptured.Theaccumulatedpartic-lime.Here,theevaporationwaterfromthescrubbingliq-ulatesorflyashfallintoahopperwhenthefabricfiltersuidiscarefullycontrolledsothatwhenthematerialreachesarecleaned,andthisashmustbedisposedofappropri-thebottomofthetower,itisadrypowder(adryflyashately.Table10.9.5liststheadvantagesanddisadvantagesandlimemixture).Thismethodeliminatesthescrubberoffabricfiltersystems.waterthatmustbetreatedordisposed;additionally,thepowerrequirementsandcorrosionpotentialarereduced.ESPsEmissiontestshavedemonstratedcontrolefficienciesofESPsconsistofoneormorepairsofelectricchargeplates99%orbetterforhydrogenchlorideandsulfurdioxideorfields.Theparticulatesinfluegasesaregivenanelec-removalunderoptimalconditions(temperaturesbelowtriccharge,forcingthemtosticktotheoppositelycharged300°F,sufficientlyhighlime/acidratios,andsufficientlyplate.ESPswithfourormorefieldsarestate-of-the-art.longgasresidencetimeinthescrubber).DioxinswerealsoTable10.9.6liststheadvantagesanddisadvantagesofconsiderablyreduced(Hershkowitz1986).ESPs.DRYINJECTIONSCRUBBERSCYCLONESDryinjectionscrubbersinjectdrypowderedlimeoran-Athirdtypeofparticulatecontroldeviceisthecyclone,aotheragentthatreactswiththeacidgasesinfluegas.Inmechanicaldevicethatfunnelsfluegasesintoaspiral,cre-oneresearchtest,removalefficienciesof99%forhydro-atingacentrifugalforcethatremoveslargeparticles.Whengenchlorideand96%forsulfurdioxideweremeasuredcombinedwithbaghousesandESPscyclonesimprovetheirunderoptimaltemperatureconditions(230°F);dioxinsefficiencybyremovinglargerparticlesbeforetheyreachwerealsoconsiderablyreduced(Plattetal.1988).theseothermoreefficientdevices.TRENDSTRENDSAreportbytheGermanequivalenttotheU.S.EPApre-Whentheyareplacedafterascrubber,particulatecontroldictsatrendtowardwetscrubbingbecauseofbetterelim-devicesalsocollectheavymetalsandotherpollutantsthatinationofsulfurdioxide,heavymetals,andothertoxichavecondensedoutoffluegasontoparticlesurfaces.substances(McIlvaine1989).Inaddition,spraydryingandPlacingascrubberfirsthelpslowerthetemperatureofotherdryprocesseshavethedisadvantageofincreasedgasesenteringafabricfilter.However,wetscrubberscan-residueproduction.Thereportdoescitepotentialprob-notprecedefabricfiltersbecausethewetparticlesinflue©1999CRCPressLLC FIG.10.9.15SchematicofCommercewaste-to-energyplantinsouthernCalifornia.(Reprinted,withpermis-sion,fromCommerceRefuse-to-EnergyAuthority.)gasesclogthefilters.Thus,facilitieswithwetscrubberstitiesonthesesmallerparticles.Thus,astate-of-the-artpar-placetheirscrubbersaftertheparticulatecontroldevice.ticulatecontroldeviceshouldachieveevenloweremissionThesmallestparticlesarethemostpotentiallydamag-levelsforparticulatesbelow2micronsindiameter.ingwheninhaledintothelungs,anddioxins,furans,acidSincemanyheavymetalscondenseattemperaturesofgases,andheavymetalsareadsorbedinthelargestquan-450°F(230°C),bothESPsandfabricfilterscollectheavyTABLE10.9.5ADVANTAGESANDDISADVANTAGESOFFABRICFILTERSYSTEMSAdvantages:Highparticulate(coarsetosubmicron)collectionefficienciesDrycollectionandsolidsdisposalRelativelyinsensitivetogasstreamfluctuations.EfficiencyandpressuredropareunaffectedbylargechangesininletdustloadingforcontinuallycleanedfiltersCorrosionandrustingofcomponentsusuallynotaproblemNohazardofhighvoltage,simplifyingmaintenanceandrepairandpermittingthecollectionofflammabledustUseofselectedfibrousorgranularfilteraids(precoating)whichpermitsthehigh-efficiencycollectionofsubmicronsmokesandgaseouscontaminantsFiltercollectorsavailableinanumberofconfigurations,resultinginarangeofdimensionsandinletandoutletflangelocationstosuitarangeofinstallationrequirementsSimpleoperationDisadvantages:Specialrefractorymineralormetallicfabrics(thatarestillinthedevelopmentalstagesandcanbeexpensive)requiredfortemperaturesinexcessof550°FFabrictreatmentstoreducedustseepingortoassistintheremovalofthecollecteddustrequiredforcertainparticulatesAfireorexplosionhazardduetoconcentrationsofsomedustsinthecollector(<50g/cum)whenasparkorflameisaccidentlyadmitted.Fabricscanburnifreadilyoxidizabledustisbeingcollected.Highmaintenancerequirements(bagreplacements,etc.)FabriclifeshortenedatelevatedtemperaturesandinthepresenceofacidoralkalineparticulateorgascomponentsCrustycakingorpluggingofthefabriccausedbyhydroscopicmaterials,condensationofmoisture(ortarry),andadhesivecomponentswhichmayrequirespecialadditivesRespiratoryprotectionformaintenancepersonnelrequiredinreplacingthefabricMediumpressure-droprequirements,typicallyintherangeof4to10inofwater©1999CRCPressLLC TABLE10.9.6ADVANTAGESANDDISADVANTAGESOFESPsAdvantages:Highparticulate(coarseandfine)collectionefficiencieswitharelativelylowexpenditureofenergyDrycollectionandsolidsdisposalLowpressuredrop(typicallylessthan0.5inofwater)DesignedforcontinuousoperationwithminimummaintenancerequirementsLowoperatingcostsCapableofoperationunderhighpressure(to150psi)orvacuumconditionsCapableofoperationathightemperatures(to1300°F)CapableofhandlinglargegasflowrateseffectivelyDisadvantages:HighcapitalcostsSensitivetofluctuationsingasstreamconditions(flow,temperature,particulateandgascomposition,andparticulateloading)DifficultyincollectingcertainparticulatesduetoextremelyhighorlowresistivitycharacteristicsRelativelylargespacerequirementsforinstallationExplosionhazardwhentreatingcombustiblegasesandcollectingcombustibleparticulatesSpecialprecautionsrequiredtosafeguardpersonnelfromhighvoltageequipmentOzoneproducedbythenegativelychargeddischargeelectrodesduringgasionizationSophisticatedmaintenancepersonnelrequiredmetalsthatcondenseontoparticulatematter.Effectivemovingnitrogenoxidesfromfluegasesarecalledselectivemercuryemissioncontroltechnology,whileevolving,hasnoncatalyticreduction(SNCR)andselectivecatalyticre-notbeenimplementedinMSWincinerators.Avolatileduction(SCR).(SeeSection5.23.)Bothtechnologieshavemetal,mercuryvaporizesunderthehightemperaturesofbeensuccessfullydemonstratedonMSWincinerators.Wetcombustionalthoughrecentresearchsuggeststhatmer-scrubbingandcondensationalsohavethecapacitytocon-curycanalsobepresentasmercuricchloride,mercuricox-trolnitrogenoxides.ides,andmercurysolids.Whereasmostvaporizedmetalsreturntoasolidstatewhencombustiongasescool,mer-curyremainsinthevaporstate.Wetscrubbing,activatedEmissionControlDevicescarbonandsodiumsulfidetechnologiesshowpromisingThearrangementofemissioncontroldevicesotherthanresults.thedevicesfornitrogenoxidesisusuallystandard:ascrub-Mercurycontrolrequiresthatthevaporbeadsorbedberandcondenser,followedbyaparticulatecollector,fol-ontoparticulatesorabsorbedintoaliquidwhichisevap-lowedbyaninductionfanthatsucksfluegasesuptotheoratedtoleavethesolids.Themercury-ladensolidsarestack.Tworeasonsforthisarrangementare:collectedintraditionalcollectiondevices.Sometechnolo-gies,usedinconjunctionwithotherpollutioncontrolsys-Fabricfilterscannotoperateatthehightemperaturesattems,cansimultaneouslyremovedioxins,furans,mercury,whichgasesexittheboilerwithoutriskoffire.Thus,andothermetalsaswellasacidgasesandparticulatesplacingthescrubberbetweentheboilerandthefabric(SeigiesandTrichon1993).filterorESPpermitscoolingandoftenhumidificationthatpreventfire.Coolingthegasesalsoplaysaroleinreducingacidgas,mercury,anddioxinemissions.NitrogenOxideEmissionsDioxinsandheavymetalsaretrappedmoreeffectivelybyparticulatecontroldeviceswhentheyarefirstcon-State-of-the-artcontrolofnitrogenoxidesrequiresbothdensedoutofthefluegasandadsorbedontothesur-minimizingtheformationofnitrogenoxidesinthefur-faceofparticulatematter,ashappensinascrubber–con-naceandtransformingthemintonitrogenandwater.densersystem.Strategiesforminimizingformationincludeusingappro-priatefurnacedesigns(suchasfluegasrecirculationandAnalternatearrangement,commoninEuropeanplants,dual-chamberedfurnaces)andoperatingpractices(suchasinvolvesanESPfollowedbyawetscrubber.TheESPisoptimaltemperaturesandamountofexcessair).Seenotdamagedbyhightemperatures,andthewetscrubberSection5.22.Techniquesfordestroyingnitrogenoxidescoolsandcondensesgasesandcapturesparticulates.involveinjectingchemicalsthatneutralizethem.Thelocationofcontroldevicesfornitrogenoxidesde-Chemicalinjectiondevicesuseammonia,urea,orotherpendsonthetypeoftechnologyused.Thesedevicescancompoundstoreactwithnitrogenoxidestoformnitro-beinthefurnacesortheboileraswellasatthebackendgenandwater.Thetechnologiesforneutralizingandre-oftheplant.©1999CRCPressLLC AshManagementTABLE10.9.7INSTRUMENTLISTFORCONTINUOUS-FEEDINCINERATORThefirstpriorityinstate-of-the-artashmanagementistoreduceboththevolumeandtoxicityoftheresidueleftaf-TemperatureRecordersterburningMSW.Removingnoncombustiblesandmate-Furnacetemperatureatfurnacesidewallnearoutlet,rangerialcontainingtoxicsubstancesfromtheMSWbeforein-38to1250°CcinerationfollowedbyefficientcombustionaccomplishesStokercompartmenttemperature,range38to1250°CDustcollectorinlettemperature,range38to500°Cthisreduction.Theamountoftoxicmaterialinashhasbeenincreasingasmoreeffectiveairpollutioncontrolde-TemperatureControllersvicescapturemorepollutantsintheflyash.FurnaceoutlettemperaturecontrolledbyregulatingtotalairState-of-the-artashmanagementpracticesaredesignedfromforceddraftfan;setpointin800to1000°CrangeDustcollectorinlettemperaturecontrolledbyregulatingtominimizeworkerandcitizenexposuretopotentiallywatersprayintofluegas;setpointin300to400°Crangetoxicsubstancesinashduringhandling,treatment,andstorage,long-termstorage,orreuse.SafeashmanagementDraftGaugeshasseveralcomponents:Forced-draft-fanoutletductInduced-draft-faninletductThebottomashorresidue(noncombustibleandpartiallyFurnaceoutletburnedsolidsleftintheincinerator)andflyash(mate-StokercompartmentsDifferentialgaugeacrossdustcollectorrialcapturedbyemissioncontroldevices)iskeptsepa-rateforrigoroushandlingofthepotentiallymoretoxicDraftControllerflyash.FurnacedraftcontrolbyregulatingdamperopeningTheashiscontainedwhilestillintheplant.Aclosedsys-OxygenAnalyzertemofconveyorsispreferabletohandlingashintheFurnaceoutletopen.Theashistransportedwetinleakproof,coveredtruckstodisposalsites.treatingthewatertoremovesolubletoxicmaterials.TheTheashistreatedtominimizeitspotentialtoxicimpact.systemhasbeenusedinEurope,particularlyinincinera-Theashisdisposedinash-onlymonofillsbecausecodis-torswithwetscrubbers(Clark,Kadt,andSaphire1991).posalofashwithMSWincreasestheleachabilityoftheashwhenitisexposedtoacid.InstrumentationFlyashfromAPCisfine-grained,notunlikesootfromfireplaces.ForeverytonofMSWburned,approximatelyContinuousprocessmonitors(CPMs)andcontinuous1/4tnbecomessomeformofash.Flyashaccountsforaboutemissionmonitors(CEMs)tracktheperformanceofin-10to15%ofthetotalashresidue;theremaining85tocineratorssothatwhencombustionupsetsorhighemis-90%isbottomash.sionsofoneormorepollutantsoccur,timelycorrectiveOperationaldatafromresourcerecoveryincinerationmeasurescanbeimplemented(seeSection5.15).Thesefacilitiesthroughouttheworldindicatecertainheavymet-monitorsareusuallyconnectedtoalarmsthatwarnplantals,suchasleadandcadmium,tendtoconcentrateintheoperatorsofanycombustion,emission,orotheroperat-flyash,scrubberresidue,andsmallparticles(lessthan3/8ingconditionthatrequiresattention.Table10.9.7liststhein)inthebottomash.Heavymetals,includinglead,cad-typicalinstrumentationoncontinuous-feedincineratorsmium,andtotalsolublesalts(includingchloridesandsul-forclosed-loopcontrolofthetemperatureanddraftcon-fates),arepotentiallyleachablecomponentswhichcanim-trollers(Shah1974).pacttheenvironment.LeachablecomponentsarethoseState-of-the-artCPMsandCEMsmeasurenineoper-chemicalspecieswhichdissolveinwaterandaretrans-atingandemissionfactors:furnaceandfluegastempera-portedwithwater.Thetoxicitycharacteristicleachingpro-tures,steampressureandflow,oxygen,carbonmonox-cedure(TCLP)andnumerousothertechniquesexisttoes-ide,sulfurdioxide,nitrogenoxides,andopacity(acrudetimatethepotentialenvironmentalimpactresultingfrommeasureofparticulates).Continuousmonitoringofhy-ashgeneration,handling,anddisposal.drogenchlorideispossibleandmaysoonbeastate-of-Twomaincategoriesofashtreatment,bothrecentlyde-the-artrequirement.Bymonitoringparametersthatindi-velopedandbeingimproved,arefixationorcementationcatecombustionefficiency(carbonmonoxide,oxygen,andandvitrification.Bothtechniquesminimizetheenviron-furnacetemperature),plantoperatorsalsoobtainindica-mentalimpactofashandenableitsreuseinsituationssuchtionsoflevelsofincompletecombustion.Operatorsmustascinderblocks,reefs,androads.Afewincineratorshaveperformfrequentmaintenance,includingperiodiccalibra-onsitevitrificationfacilities.tion,oncontinuousmonitorstoensuretheiraccuracy.AnothernewtreatmenttechnologyinvolveswashingAdaptedfromMunicipalWasteDisposalinthe1990sthetoxicmaterialsoutoftheashwithhotwaterandthenbyBélaG.Lipták(Chilton,1991).©1999CRCPressLLC ReferencesSeigies,J.andM.Trichon.1993.Wastetoburn.PollutionEngineering(15February).Clark,M.J.,M.Kadt,andD.Saphire.1991.BurninggarbageintheUSShah,I.S.1974.Scrubbers.Sec.5.12–5.21inEnvironmentalengineersEditedbySibylR.Golden.NewYork:INFORM,Inc.handbook,editedbyB.G.Lipták.Radnor,Pa.:ChiltonBookEberhardt,H.1966.Europeanpracticesinrefuseandsewagesludgedis-Company.posalbyincineration.ASMENationalIncineratorConference,NewSommer,Jr.,E.J.andG.Kenny.1984.EffectsofmaterialsrecoveryonYork,1966.waste-to-energyconversionatGallatin,Tennesseemassfiredfacility.Essenhigh,R.H.1974.Incinerators—theincinerationprocess.Vol.2inProc.WasteProcessingConf.NewYork:ASME.Environmentalengineers’handbook,editedbyB.G.Lipták.Radnor,Stelian,J.andH.L.Greene.1986.OperatingexperienceandperformancePa.:ChiltonBookCompany.oftwoashhandlingsystems.NationalWasteProcessingConference,Gibbs,D.R.andL.A.Kreidler.1989.WhatRDFhasevolvedinto.WasteDenver,1986.ASME.Age(April).U.S.EnvironmentalProtectionAgency.1991.BurningofhazardousHershkowitz.1986.Garbageburning:LessonsfromEurope:Consensuswasteinboilersandindustrialfurnaces,finalruling.FederalRegisterandcontroversyinfourEuropeanstates.NewYork:INFORM,Inc.56,no.35(21February):7134–7240.Licata,A.J.1986.Designforgoodcombustion.24January,1986,Velzy,C.O.1968.Theenigmaofincineratordesign.ASMEWinterMunicipalSolidWasteForum,MarineSciencesResearchCenter,AnnualMeeting,NewYork,1968.StateUniversityofNewYork,1986.Velzy,C.O.andR.S.Hechlinger.1987.Incineration.Sec.7.4inMark’sLicata,A.J.,R.W.Herbert,andU.Kaiser.1988.Designconceptstomin-standardhandbookformechanicalengineers,9thed.EditedbyT.imizesuperheatercorrosioninmunicipalwastecombustors.NationalBaumeisterandE.A.Avallone.NewYork:McGraw-Hill.WasteProcessingConference,Philadelphia,1988.NewYork:ASME.Wheless,E.andM.Selna.1986.Commercerefuse-to-energyfacility:AnMcIlvaine,R.W.1989.IncinerationandAPCtrendsinEurope.Wastealternativetolandfilling.NationalWasteProcessingConference,Age(January).Denver,1986.ASME.Platt,Brendaetal.1988.GarbageinEuropetechnologies,economics,andtrends.InstituteforLocalSelfReliance(May).10.10SEWAGESLUDGEINCINERATIONSewagesludge,thestabilizedanddigestedsolidwastecostofpayfuelandtheassociatedodorandpollutionproductofthewastewatertreatmentprocess,canbedis-problems.Themultiple-hearthdesign,themostwidelyposedofbylandfilling,incineration,composting,oroceanusedforsludgeincineration,reducesodorandpollutiondumping.Naturereturnsorganicmaterialtothesoilasbutprovideslessoperatingflexibilitybecauseitcannotdryfertilizer.Organicmaterialbecomeswastewhenitisnotthesludgewithoutincineratingit.Themostrecentandad-returnedtothesoilbutinsteadisburned,buried,orvanceddesignisthefluidized-bedsludgeincinerator,whichdumpedintheocean.Theseunhealthypracticesbegancanoperateineitherthecombustionorpyrolysismode.whenchemicalfertilizerstookthemarketawayfromTheexhausttemperaturefromafluidized-bedincineratorsludge-basedcompostandwhenindustrialwastebegantoishigherthanfromamultiple-hearthfurnacesoafter-contaminatesewagesludgewithtoxicmetals(leadandburnersarelesslikelytobeneededtocontrolodor.cadmium),makingitunusableforagriculturalpurposes.TheauxiliaryfuelcostofsludgeincinerationishigherUntilrecently,thebulkofthesewagesludgegeneratedbywithfluidized-bedincineratorsthanwithmultiplehearths.metropolitanareashasbeeneitherlandfilledordumpedThecostvariesaccordingtothemoisturecontentoftheintheocean.Theseoptionsaregraduallydisappearingandsludgeandthedegreeofheatrecovery(Sebastian1974a).asaresultmunicipalitieswillhavetomakesomehardde-Eliminatingtheneedforauxiliaryfuelrequiresthatthecisions.(SeeSections7.31to7.56).dry–solidcontentexceed25%formultiple-hearthand32%forfluidized-bedincinerators(Sebastian1974a).Insomefluidized-bedinstallationsinJapan,operatingcostsSludgeIncinerationEconomicshavebeencutinhalfthroughheatrecovery(Henmi,IncineratingsewagesludgehasbeenpracticedforthelastOkazawa,andSota1986).sixtyyears.Earlydesignswereeitherflash-dryingormul-Inamultiple-hearthincineratorwithafeedcontainingtiple-hearthtypes,whileinrecentyearsfluidized-bedin-10%solids,theashisabout10%ofthefeed.Tablecineratorshavealsobeenused.Theflash-dryingprocess10.10.1givesthecompositionofincineratorashes.Thehasalowcapitalcostandisflexibleinthatitcanproduceashiseitherlandfilledormarketedasasoilconditioner.theamountofdriedsludgethatmarketsneed;there-Table10.10.2givesthecompositionofVitalin,theashmaindercanbeincinerated.ItslimitationsaretheaddedfromTokyo’sOdaiplant.(TheJapanesewordlinmeans©1999CRCPressLLC TABLE10.10.1TYPICALANALYSISOFASHFROMTERTIARYQUALITY-ADVANCEDWASTETREATMENTSYSTEMSPercentofTotalSampleLakeTahoeLakeTahoeMinn.–St.PaulClevelandContent11/19/6911/25/699/30/693/2/70Silica(SiO2)23.8523.7224.8728.85Alumina(Al2O3)16.3422.1013.4810.20Ironoxide(Fe2O3)3.442.6510.8114.37Magnesiumoxide(MgO)2.122.172.612.13Totalcalciumoxide(CaO)29.7624.4733.3527.37Available(free)calciumoxide(CaO)1.161.371.060.29Sodium(Na)0.730.350.260.18Potassium(K)0.140.110.120.25Boron(B)0.020.020.0060.01Phosphoruspentoxide(P2O5)6.8715.359.889.22Sulfateion(SO4)2.792.842.715.04Lossonignition2.592.241.621.94phosphorus).ThetermsoilconditionerisusedinsteadofIntheflash-dryingprocess(seeFigure10.10.1),thewet,fertilizerbecausethephosphatecontentislessthan12%,dewateredsludgeismixedwithdrysludgefromthedryerthenitrogencontentisunder6%,andthetotalNPKcon-cyclone.Thispreconditionedmixturecontactsagasstreamtentislessthan20%.of1000to1200°F,whichmovesitatavelocityofseveralthousandfeetperminute.Inthisturbulent,high-temper-aturezone,themoisturecontentofthesludgeisreducedIncinerationProcessesto10%orlessinonlyafewseconds.Asthemixtureen-Adescriptionoftheflash-dryer,multiple-hearth,fluidized-tersthedryercyclone,thehotgasesareseparatedfromthebedandfluidized-bedwithheatrecoveryincinerationfine,fluffyheat-driedsludge.Dependingonthemodeofprocessesfollows.operation,theflash-driedsludgeiseithersenttothesludgeburnerandincineratedat1400°F,oritissenttothefer-tilizercycloneandrecoveredasasaleablefertilizerprod-FLASH-DRYERINCINERATIONuct.Whentheincomingwetsludgecontainsabout18%Theflash-dryerincineratorprocesswasfirstintroducedinsolids,about6500Btu(Aslbofcoalplus1cuftofnat-the1930sasalow-capital-cost,space-savingalternativetouralgas)arerequiredtoproduce1lbofdrysludge(15,000airdryingsludgeonsandbeds.ThismethodofdryingiskJ/kg)(Shell1979).advantageousbecausetheresultingheat-driedsludgeisvir-tuallyfreeofpathogensandweedseedsandtheprocessisMULTIPLE-HEARTHINCINERATIONflexibleenoughtoproduceonlytheamountofdriedsludgethatcouldbemarketed.ThedisadvantagesofthisprocessMultiple-hearthincinerationwasdevelopedin1889andaredustandodor.Theseproblems,whilemanageablewasfirstappliedtosludgeincinerationinthe1930s.Itisthroughtheuseofdustcollectorsandafterburners,makethemostwidelyusedmethodofsludgeincinerationtheflash-dryerlesspopularthanmultiple-hearthandflu-(Sebastian1974b).Themultiple-hearthfurnaceconsistsofidized-bedincinerators.asteelshelllinedwitharefractory(seeFigure10.10.2).Horizontalbrickarchesseparatetheinteriorintocom-partments.Thesludgeisfedthroughtheroofbyascrewfeederorabeltfeederandflapgateatarateofabout7toTABLE10.10.2COMPOSITIONOFMULTIPLE-12lbpersqft.RotatingrabblearmspushthesludgeacrossHEARTHINCINERATIONASHthehearthtodropholes,whereitfallstothenexthearth.FROMTHEODAIPLANTINTOKYOAsthesludgetravelsdownwardthroughthefurnace,itSilicaoxide30.00Potassium1.00turnsintoaphosphate-ladenash(seeTables10.10.1andMagnesiumoxide3.30Nitrogen0.2010.10.2).Calciumoxide30.00Manganese0.06Thesludgeisdriedintheupper,orfirst,operatingzonePhosphoricoxide6.20Copper0.61oftheincinerator.Inthesecondzone,itisincineratedatFerricoxide18.20Boron200.00ppmatemperatureof1400to1800°F(760to982°C)andde-Note:AshismarketedunderthetradenameVitalin.odorized.Inthethirdzone,theashiscooledbythein-©1999CRCPressLLC FIG.10.10.1Sludgedryingandincinerationusingadeodorizedflash-dryingprocess.comingcombustionair.Theair,whichtravelsincoun-stroymalodoroussubstancessuchasbutyricandcaproicterflowwiththesludge,isfirstpreheatedbytheash,thenacids.Theneedforafterburnersisafunctionoftheex-participatesinthecombustion,andfinallysweepsoverthehaustgastemperature.Usuallyattemperaturesabove700coldincomingsludgedryingituntilthemoisturecontentto800°F(371to427°C)inawell-controlledincineratorisabout48%.Atthispercentageofmoisturecontent,awherethecombustionprocessiscomplete,afterburnersphenomenoncalledthermaljumpoccursasthesludgeen-arenotnecessaryforodor-freeoperation.Ifcombustiontersthecombustionzone.Thethermaljumpallowstheisnotcomplete,however,theexhaustgastemperaturesludgetobypassthetemperaturezonewheretheodorismighthavetoriseto1350°F(732°C)beforetheodorisdistilled.Theexhaustgasesare500to1100°F(260todistilled.Insuchcases,installinganafterburnerislessex-593°C)andareusuallyodor-free.Thesludgetemperaturepensivethanusingauxiliaryfueltoachievesuchhighex-profileacrossthefurnaceisshowninTable10.10.3.hausttemperatures.Thepollutioncontrolequipmentusuallyincludesthree-Iftheincomingsludgecontains75%moistureandifstageimpingement-typescrubbersforparticulateandsul-70%ofthesludgesolidsarevolatile,theincinerationfurdioxideremovalandstandbyafter-burners,whichde-processproducesabout10%ash.Theashcanbeusedasasoilconditionerandastherawmaterialforbricks,con-creteblocks,androadfills,oritcanbelandfilled.IntheUnitedStatesthesupplyofphosphatesissufficientforlessthanacentury(Sebastian1974b),sothephosphatecon-tentofsludgeashisimportant.IftheashalsocontainsTABLE10.10.3SLUDGEFURNACETEMPERATUREPROFILEApproximatelyNominalatHalfDesignHearthCapacityCapacityNo.(°F)(°F)106700800213801200315601650414501450512001200603250300FIG.10.10.2Multiple-hearthincinerationofsludge.©1999CRCPressLLC zincorchromium,itcandamagecertaincropsalthoughitdoesnotdamagecerealsorgrass(Sebastian1974b).Theharmfuleffectsaremorelikelytooccurinacidicsoilsandcanbeoffsetbytheadditionoflimetothesludge.Themainadvantagesofmultiple-hearthincineratorsin-cludetheirlonglifeandlowoperatingandmaintenancecosts(Sebastian1974b);theirabilitytohandlesludgeswithamoisturecontentofupto75%withoutrequiringaux-iliaryfuel;theirabilitytoincinerateorpyrolizehard-to-handlesubstances,suchasscumorgrease;theirabilitytoreclaimchemicaladditives,suchaslimeincombinationwithorseparatelyfromincineratingthesludge;andtheirflexibility,inthattheycanbeoperatedintermittentlyorcontinuouslyatvaryingfeedratesandexit-gastempera-FIG.10.10.3Multiple-hearthincineratorfuelconsumptionastures(Sebastian1974b).Theauxiliaryfuelrequirementafunctionofmoisturecontentinthefeedandpercentageofvarieswiththedry–solidscontentofthesludgeandwithvolatilesolids.Notes.1.Curvesarenotapplicableforfeedratesthepercentageofvolatilesinthesolids(seeFigure10.10.3).below4tnperhr.2.Curvesdonotincludeallowanceforlimeasafilteraid.3.Tocorrectforlime,downgradevolatilesolidsaccordingtolimedosage.Assuminglimeformscalciumhy-droxide,eachpoundofCaOforms1.32lbcalciumhydroxide.FLUIDIZED-BEDINCINERATION4.Naturalgascalorificvalueisassumedtobe100Btupercuft.5.Heatcontentofsludgeisbasedon10,000BtuperlbofFluidized-bedincinerationcanhandlesewagesludgecon-volatilesolids.6.%V.S.representspercentageofvolatilesolidstainingasmuchas35%solids.Thesludgeisinjectedintointhefeed.afluidizedbedofheatedsand.Theincineratorisaverti-calcylinderwithanairdistributionplatenearthebottom,whichallowstheairtoenterthesandbedwhilealsosup-FIG.10.10.4Flowdiagramofsewagesludgeincinerationplantwithindirectheatdryer.(Reprinted,withpermission,fromM.Henmi,K.Okazawa,andK.Sota,1986,Energysavinginsewagesludgeincinerationwithindirectheatdrier,NationalWasteProcessingConference,Denver,1986[ASMER].)©1999CRCPressLLC TABLE10.10.4OPERATIONALDATAOFFLUIDIZED-BEDSLUDGEINCINERATORWITHANDWITHOUTINDIRECTHEATINGDirectIncineration(WithoutDrying)IncinerationwithDriedCakeDesignRun1Run2DesignRun3Run4Run5Run6InputCake(tpd)00800060008000960060008000960070CakePropertyMoisture(%)007883–86¬75–8083–86¬¬78–80(84.7)¬(78)(84.8)(79)Combustibles(%ds)56–6480.2–80.7¬56–6480.1–80.279.1–79.479.3–80.4(60)(80.5)¬(60)(80.2)(79.3)(84.7)(80)Lowerheatingvalue12.618.5–18.912.618.718.818.518.8(MJ/kgds)(18.7)¬DriedCakeMoisture(%)samesamesame66–7380.1–80.979.8–80.679.2–80.270–72(70)(80.6)(80.2)(79.7)(71)Weight(tpd)0080006000807046.761.872.443SupportingFuel(l/h)03120238026500470092009400960(l/tncake)00940095008000120037002800240FurnaceTemperatureSandbed(°C)08000790780–8200800770–810770–810760–810(800)(780)(780)(780)(780)Outlet(°C)08500860850–9500800760–800760–800760–810(900)(780)(780)(780)(780)Fluidizingair(cumNormal/h)75006400750055005500550055005500Excessairratio1.401.621.521.562.021.611.41(1.8)Source:M.Henmi,K.Okazawa,andK.Sota,1986,Energysavinginsewagesludgeincinerationwithindirectheatdrier,NationalWasteProcessingConference,Denver,1986(ASMER).Note:Valuesinparenthesesareaveragevalues.Allunitsareinmetric(SI).portingit.Astheairflowincreases,thebedexpandsandature.Sincereactionratesarerelatedtobedmixingandbecomesfluidized.Thesolidwasteinthesludgecanbethesourceofagitationisthefluidizingair,operatorscandestructedbyeithercombustionorpyrolysis.adjustreactionratesbychangingtheairflowsupply.TheDuringcombustiontheorganicmaterialisturnedintobedtemperatureisusuallymaintainedbetween1300andcarbondioxide:1500°F(704to815°C).Forcompletecombustion(odor-freeoperation),about25%excessairisneeded(RaboskySewageSludge1Oxygen®CO21H2O1Ash1Heat1974).10.10(1)Organicmaterialcanbedepositedonthesandparti-Theheatofcombustionhelpsmaintainthefluidizedbedcles(agglomerativemode)andremovedbycontinuousoratatemperatureofabout1400°F(760°C).intermittentwithdrawalofexcessbedmaterial.Analter-Inthepyrolysisprocess,thesludgeisdecomposedinnativemodeofoperation(nonagglomerative)combinesthethepresenceofinertgasesat1400°F(760°C),whichyieldsorganicasheswithexhaustgasesandcollectsthemdown-hydrogen,methane,carbonmonoxide,andcarbondiox-streamwithdustcollectors.ide.Forpyrolysis,auxiliaryheatisrequiredtomaintainThemainadvantagesoffluidized-bedincineratorsin-thefluidizedbedatthehighreactiontemperature:cludetheuniformityofthebed,theeliminationofstrati-ficationandhotorcoldspots,thehighrateofheattrans-SewageSludge1InertGas--->ferforrapidcombustion,theeliminationofodorandtheH21CO1CO21CH41AuxiliaryHeat10.10(2)needforafterburners,andthelowmaintenancerequire-Theoperationofthefluidized-bedincineratorisopti-mentsoftheprocess.Thedisadvantagesincludethehighmizedbycontroloftheairflowrateandthebedtemper-operating-powerrequirement,theneedforauxiliaryfuel©1999CRCPressLLC TABLE10.10.5OPERATINGCOSTSOFFLUIDIZED-BEDSLUDGEINCINERATIONWITHANDWITHOUTHEATRECOVERYNormalUndriedCakeNewlyDevelopedIndirectlyIncinerationDriedCakeIncinerationUtilityItemsUnitCostAmountCostAmountCostPlantCapacity80tn/d96tn/dOperationCostUS$/dUS$/d1.Supportingfuel0.35US$/l6360l/d22262304l/d8062.Electricity0.1US$/kWh10800kWh/d108010300kWh/d10303.Chemical0.35US$/kg220kg/d77151kg/d53(NaOH)4.Lubrications2.6US$/l0.8l/d20.8l/d2TotalperDay——3385US$/d—1891US$/dUnitTreatmentCost——42.3US$/tn—19.7US$/tnperInputCakeVol.Source:Henmi,Okazawa,andSota1986.Note:Allunitsareinmetric(SI).ifthedrysolidconcentrationislessthan32%andthe(Henmi,Okazawa,andSota1986).Theplantshowninneedfordust-collectiondevices.Figure10.10.4hasbeeninoperationinTokyosince1984(Henmi,Okazawa,andSota1986).Heatrecoveryinvolvesinsertingaheatexchangerintothestreamofthehotgases,FLUIDIZED-BEDINCINERATIONWITHwhichgeneratesasupplyofhotthermaloil.TheoilisthenHEATRECOVERYusedastheenergysourcetoheatthesludgecakedryers.Theadditionofheat-recoveryequipmentcanincreasetheThehotoilpassesthroughthehollowinsideofthemo-capacityoffluidized-bedincineratorsbyabout20%tor-drivenscrews,whilethesludgecakeisbothmovedandTABLE10.10.6CONCENTRATIONOFPOLLUTANTSINATMOSPHERICEMISSIONSANDINASHPRODUCEDBYAFLUIDIZED-BEDTYPESLUDGEINCINERATORItemsRegulationsRun1Run4ExhaustGasSulfuroxides(SOx)292ppm4ppm25ppmNitrogenoxides(NOx)250ppm—41ppmHydrogenchloride(HCl)93ppm3ppm—333Dustdensity0.05g/mN0.006g/mN0.002g/mNResidualAshAmount7.0tn/d2.4tn/d2.9tn/dIgnitionloss,15%0.6%0.6%DissolutiontowaterAlkylmercury(Hg)—,0.0005—Totalmercury(Hg)0.050,0.0005—Cadmium(Cd)0.100,0.0500—Lead(Pb)1.100,0.2000—Phosphorus(P)0.200,0.0100—Chromium61(Cr[VI])0.500,0.0500—Arsenic(As)0.500,0.1900—Cyanide(—CN)1.100,0.0500—Polychlorinatedbiphenyls(PCB)0.003,0.0005—Source:Henmi,Okazawa,andSota1986.Notes:Valuesmarked(—)werenotmeasured.Suffix“N”meansthevalueconvertedatnormalconditionof273K,1atm.©1999CRCPressLLC TABLE10.10.7CONCENTRATIONOFWASTEWATERGENERATEDBYFLUIDIZED-BEDINCINERATORWetElectrostaticDryerPrecipitationDehumidifierContent(mg/l)FeedWaterCondensateEffluentEffluentTkj—N24.7129.6724.9724.521NH4—N21.1424.4021.2420.75Org—N3.575.273.733.772NO2—N0.180.16N.D.0.112NO3—N0.630.600.980.62T—N25.5230.4325.9525.25BOD6.8641.52.243.44CODmn12.221.438.812.5SS3.315.784.02.32Cl74.374.558.376.1Source:Henmi,Okazawa,andSota1986.heatedbythesescrews.AsshowninTable10.10.4,theTable10.10.6givesthecompositionoftheashresiduecakeisdriedtoasubstantialdegree(some20%ofthein-andthestackgases(aftertheyhavebeencleanedbywetletflowisevaporated)asthesludgecakepassesthroughelectrostaticprecipitation);bothmeetJapaneseregula-thecakedryer.Theheatingoilcirculatesinaclosedcycletions.Table10.10.7givesthecompositionofthewaste-andismaintainedatabout480°F(250°C)insidethescrew-waterproducedbythisprocess.Accordingtotheopera-conveyordryersbythethrottlingoftwothree-wayvalves.tors,theprocessproducesalmostnoodor.Onevalvecanincreasetheoutletoiltemperaturefromthecakedryersbyblendinginwarmerinletoil;theothercanAdaptedfromMunicipalWasteDisposalinthe1990slowertheoutlettemperaturebysendingsomeoftheoilbyBélaG.Lipták(Chilton,1991).throughanoilcooler.TheoperatorsoftheTokyoincineratorfeelthatthetotalcapitalcostoftheplantisunaffectedbytheaddi-Referencestionoftheheat-recoveryfeaturebecausethecostoftheHenmi,M.,K.Okazawa,andK.Sota.1986.Energysavinginsewageheat-transferequipmentisbalancedbythereducedca-sludgeincinerationwithindirectheatdrier.NationalWastepacityrequirement.Theoperatingcosts,ontheotherProcessingConference,Denver,1986.ASMER.hand,arecutinhalfwiththeheat-recoverysystem(TableRabosky,J.G.1974.Incineration—fluidizedbedincineration.Vol.3,Sec.2.23inEnvironmentalengineers’handbook,editedbyB.G.Lipták.10.10.5).Radnor,Pa.:ChiltonBookCompany.AnotherinterestingfeatureofthissystemisthemethodSebastian,F.1974a.Incineratoreconomics.Vol.3,Sec.2.17inofcleaningtheaccumulationofashandsootfromtheEnvironmentalengineers’handbook,editedbyB.G.Lipták,Radnor,heat-transfersurfaces.Thisautomatedsystemuses3-toPa.:ChiltonBookCompany.5-mm-diametersteel-shotballsthataredroppedevery———.1974b.Multiplehearthincineration.Vol.3,Sec.2.22inEnvironmentalengineers’handbook,editedbyB.G.Lipták.Radnor,threetosixhoursfromthetopofthehot-airheaters.ThePa.:ChiltonBookCompany.randommovementoftheballsremovesthedustfromtheSnell,J.R.1974.Flashdryingorincineration.Vol.1,Sec.8.6inheatertubes.Thedustisremovedatthebottom,whiletheEnvironmentalengineers’handbook,editedbyB.G.Lipták.Radnor,ballsarecollectedandreturnedtothetop.Pa.:ChiltonBookCompany.©1999CRCPressLLC 10.11ONSITEINCINERATORSPARTIALLISTOFINCINERATORSUPPLIERSThissectiondescribessomeofthesmallerincineratorunitsAirPreheaterCo.,Inc.;AmericanSchackCo.,Inc.;Aqua-Chem,usedonsiteindomestic,commercial,andindustrialappli-Inc.;BSPCorp.,Div.ofEnvirotechSystems,Inc.;Bartlett-Snow;cations.OnsiteincinerationisasimpleandconvenientBeloit-PassavantCorp.;BestCombustionEngrg.Co.;BethlehemmeansofhandlingthewastetransportationproblemsinceCorp.;BrulePollutionControlSystems;C-ERaymond;CarborundumCo.;PollutionControlDiv.,Carver-Greenfielditreducesthevolumeofdisposablewaste.Onsiteinciner-Corp.;CoenCo.;CombustionEquipmentAssoc.Inc.;Copelandatorsaresmallerandtheirfuelmorepredictableincom-Systems,Inc.;DallyEngineering-ValveCo.;Dorr-OliverInc.;DravopositionthantheMSWburnedinmunicipalincinerators.Corp.;EnvironmentalServicesInc.;Envirotech;FirstMachineryTherefore,thissectiondiscussesseparatelyconsiderationsCorp.;FosterWheelerCorp.;FullerCo.;Garver-Davis,Inc.;Havegthataffectthelocation,selection,andoperatingpracticesIndustriesInc.;Holden,A.F.,Co.;Hubbell,Roth&Clark,Inc.;Intercontek,Inc.;InternationalPollutionControl,Inc.;oftheseonsiteunits.Ishikawajima-HarimaHeavyIndustriesCo.,Ltd.;KennedyVanSaunCorp.;Klenz-Aire,Inc.;Koch&Sons,Inc.;KochEngrg.Co.,Inc.;Kubota,Ltd.,Chuo-Ku,Tokyo,Japan;LawlerCo.,LeavesleyLocationIndustries;LurgiGesellschaftfuerWaerm&ChemotecHnikmbH,6Frankfurt(Main)Germany;MaxonPremixBurnerCo.,Inc.;TheonsiteincineratorshouldbelocatedclosetolargerMelsheimer,T.,Co.,Inc.;Midland-RossCorp.,RPCDiv.;Mid-sourcesofwasteandexpectedwastecollectionroutes.SouthMfg.Corp.;Mine&SmelterSupplyCo.;MSIIndustries;Onsiteincineratorsareconstructedof12-gaugesteelcas-MitsubishiHeavyIndustries,Ltd.,Tokyo,Japan;MonsantoBiodizeSystems,Inc.;MonsantoEnviro-ChemSystemsInc.;ingwithhigh-temperature(over1000°F)insulationandNicholsEngrg.&ResearchCorp.;NorthAmericanMfg.Co.;high-qualityrefractorylining.Indoorinstallationsarepre-Oxy-Catalyst,Inc.;P.D.ProcesEngrg.Ltd.,Hayes,Middlesex,ferred,butevenwhentheincineratorissituatedoutdoors,England;PeabodyEngrg.Corp.;PicklandsMather&Co.,PrencothechargingandcleanoutoperationsshouldbeshieldedDiv.;PlibricoCo.;PrencoMfg.Co.;PyroIndustries,Inc.;Reconfromtheweather.IncineratorroomsshouldbedesignedSystemsInc.;Renneburg&SonsCo.;Rollins-Purle,Inc.;RossEngrg.Div.,Midland-RossCorp.;RotodyneMfg.Corp.;Rustfortwo-hourfireresistanceandshouldcomplywiththeEngrg.Co.,Div.ofLittonIndustries;Sargent,Inc.;SurfaceNationalFireProtectionAssociation(NFPA)recommen-CombustionDiv.,Midland-RossCorp.;Swenson,Div.ofWhitingdationscontainedinbulletinNFPANo.82.Corp.;Tailor&Co.,Inc.;TakumaBoilerMfg.Co.,Ltd.,Osaka,TheIncineratorInstituteofAmerica(IIA)separatesin-Japan;ThermalResearch&Engrg.Co.;TorraxSystems,Inc.;cineratorsintonineclassesaccordingtotheiruseandsizeVulcanIronWorks,Inc.;WalkerProcessEquip.,Div.ofChicagoBridge&IronCo.;WestinghouseWaterQualityControlDiv.,(seeTable10.11.1)andprovidesminimumconstructionInfilco;Zink,John,Co.;ZurnIndustries,Inc.andperformancestandardsforeachclass.TheNFPAhasTABLE10.11.1CLASSIFICATIONOFINCINERATORSClassI—Portable,packaged,completelyassembled,direct-feedincineratorshavingnotover5cuftstoragecapacityor25lb/hrburningrate,suitablefortype2waste.ClassIA—Portable,packagedorjobassembled,direct-feedincineratorshavingaprimarychambervolumeof5to15cuftoraburn-ingrateof25lb/hrupto,butnotincluding,100lb/hroftype0,1,or2waste;oraburningrateof25lb/hrupto,butnotin-cluding,75lb/hroftype3waste.ClassII—Flue-fed,singlechamberincineratorswithmorethan2cuftburningareafortype2waste.Thisincineratortypeisservedbyoneverticalfluefunctioningasachuteforbothchargingwasteandcarryingtheproductsofcombustiontotheatmosphere.Thisincineratortypeisinstalledinapartmentormultipledwellings.ClassIIA—Chute-fed,multiplechamberincineratorsforapartmentbuildingswithmorethan2cuftburningarea,suitablefortype1or2waste.(Notrecommendedforindustrialinstallations).Thisincineratortypeisservedbyaverticalchuteforchargingwastefromtwoormorefloorsabovetheincineratorandaseparateflueforcarryingtheproductsofcombustiontoatmosphere.ClassIII—Direct-feedincineratorswithaburningrateof100lb/hrandmoresuitableforburningtype0,1,or2waste.ClassIV—Direct-feedincineratorswithaburningrateof75lb/hrormoresuitableforburningatype3waste.ClassV—Municipalincineratorssuitablefortype0,1,2,or3wasteoracombinationofallfourwastesandareratedintonsperhourortonspertwenty-fourhours.ClassVI—Crematoryandpathologicalincineratorssuitableforburningtype4waste.ClassVII—Incineratorsdesignedforspecificby-productwaste,type5or6.Note:Forwastetypenumbers,seeTables10.11.2and10.11.3.©1999CRCPressLLC ©1999CRCPressLLCTABLE10.11.2CLASSIFICATIONOFWASTESTOBEINCINERATEDRequirementRecommendedClassificationBtuforAuxiliaryMinimumBtuofWasteApproximateMoistureValue/lbFuelBtuBurnerInputTypeandComposition,Content,IncombustibleofRefuseperlbperlbDensityDescriptionPrincipalComponents%byWeight%Solids,%asFiredofWasteWastelb/cuft0TrashHighlycombustibleTrash1001058500008–10waste,paper,wood,cardboardcartons,andupto10%treatedpapers,plasticorrubberscraps;commercialandindustrialsources1RubbishCombustiblewaste,Rubbish8025106500008–10paper,cartons,Garbage20rags,woodscraps,combustiblefloorsweepings;domestic,commercial,andindustrialsources2RefuseRubbishandgarbage;Rubbish5050743000150015–20residentialsourcesGarbage503GarbageAnimalandvegetableGarbage6570525001500300030–35wastes,restaurants,Rubbish3hotels,markets;institutionalcommercial,andclubsources4AnimalCarcasses,organs,Animaland85510003000800045–55solidssolidorganichuman(5000primary)andwastes;hospital,tissue(3000secondary)organicslaboratory,100abattoirs,animalpounds,andsimilarsources5Gaseous,IndustrialprocessVariableDependentonVariableVariableVariableVariableVariableliquid,wastesmajororcomponentssemi-liquid6SemisolidCombustiblesrequiringVariableDependentonVariableVariableVariableVariableVariableandhearth,retort,ormajorsolidgrateequipmentcomponents TABLE10.11.3INDUSTRIALWASTETYPESTypeofWastesDescription1Mixedsolidcombustiblematerials,suchaspaperandwood2Pumpable,highheatingvalue,moderatelylowash,suchasheavyends,tankbottoms3Wet,semisolids,suchasrefuseandwatertreatmentsludge4Uniform,solidburnables,suchasoff-specorwastepolymers5Pumpable,highash,lowheatingvaluematerials,suchasacidorcausticsludges,orsulfonates6Difficultorhazardousmaterials,suchasexplosive,pyrophoric,toxic,radioactive,orpesticideFIG.10.11.1Featuresofadomesticincinerator.residues7Othermaterialstobedescribedindetailoneforchargestorageandtheotheranevacuatedcham-berforcombustion.Thechargechambercanbeloadedatalsoinstitutedsimilarclassificationsandconstructionstan-anytime.Sizingisbasedonthepounds-per-hourburningdardsinitsstandardIncineratorsandrubbishhandling.raterequired.TheIIAalsoclassifieswasteintoseventypes(seeTablesThenatureandcharacteristicsofthewasteareusually10.11.2and10.11.3).Plannersmustalsocomplywithlo-summarizedinaformsuchasthatinTable10.11.4.Mostcalandstatecodeswhenselectinganincinerator.incineratormanufacturersofferstandard,pre-engineeredpackagesforwastetypes0,1,2,3,and4(seeTablesSelection10.11.2and10.11.3).Wastetypes5and6usuallyrequireuniquedesignsbecausethephysical,chemical,andther-Thefirststepinincineratorselectionistorecordthevol-malcharacteristicsofthesewastesarevariable.Type6ume,weight,andclassesofwastecollectedforaperiodofwastetendstohavelowheatingvaluesbutcontainsma-atleasttwoweeks.Thesurveyshouldbecheckedagainstterialthatcancauseintensecombustion.Plasticsandsyn-typicalwaste-productionrates.Themaximumdailyoper-theticrubberdecomposeathightemperaturesandformationcanbeestimatedasthreehoursforapartmentbuild-complexorganicmoleculesthatrequireauxiliaryheatandings;fourhoursforschools;sixhoursforcommericalhighturbulencebeforetheyarefullyoxidized.Inextremebuildings,hotels,andotherinstitutions;andsevenhourscases,threecombustionchambersarenecessary;operatorspershiftforindustrialinstallations.mustrecyclefluegasesfromthesecondarycombustionTheresultsofthewastesurveyhelptodeterminechamberbackintotheprimarychambertocompletethewhetheracontinuousorbatch-typeincineratorshouldbecombustionprocess.installed.Batch-typeunitsconsistofasinglecombustionchamber(seeFigure10.11.1).Ifthebatchfurnacehasnograte,theashaccumulationreducestherateofburning.ChargingThebatchincineratorissizedaccordingtotheweightofeachtypeofwasteperbatchatthenumberofbatchesperIncineratorscanbechargedmanuallyorautomatically;day.Thecontinuousincineratorconsistsoftwochambers:theycanalsobechargeddirectly(seeFigure10.11.2)orTABLE10.11.4WASTEANALYSISSHEET%Ash___________________%Sediment___________________%Water____________________Wastematerialsolubleinwater?_________Watercontentwellmixed,emulsified?____________Iftherearesolidsintheliquid,whatistheirsizerange?_____________________________________Conradsoncarbon______________________Corrosion(copperstrip)_________________________Isthematerialcorrosivetocarbonsteel?______________Corrosivetobrass?__________________Whatalloyisrecommendedforcarryingthefluid?_________________________________________Distillationdata(ifapplicable)10%at________°F;90%at________°F;endpoint________°F.Flashpoint_______________°F;firepoint_______________°F;pourpoint_______________°F.Viscosity_________________________SSFat122°For_________________________SSUat100°F.pH__________________;acidnumber___________________;basenumber___________________Heatingvalue_________________Btu/galSpecificgravity(H2O51.0)_______________________Willthematerialburnreadily?___________________________________________________________Toxic?(explain)_______________________________________________________________________©1999CRCPressLLC FIG.10.11.2Incineratorwitharam-feedsystem.Hydraulicplungersorramsofferamorecontrolledmethodofautomaticcharging.Themovementofthere-ciprocatingplungerforcestherefusefromthebottomofthechargehopperintothefurnace(seeFigure10.11.2).Thismethodisthemostcommonforautomaticchargingforcapacitiesexceeding500lbperhour.Incineratorsthatburnsawdustorshreddedwastearefrequentlychargedbyscrewfeedersorpneumaticcon-veyors.Screwfeedersareatleast6in(15cm)indiameterandaredesignedwithvariablepitchtominimizethecom-pression(andthereforeblocking)oftheshreddedwaste.Containercharging,whichisbeingusedinafewisolatedcases,hastheadvantageofprotectingagainstexposuretoflashbackcausedbyaerosolcansorthesuddencombus-tionofhighlyflammablesubstances.AccessoriesFIG.10.11.3Top-chargingincinerator.Forsmallerincinerators,chimneysprovidesufficientdrafttodischargefluegasesatahighenoughpointwherenofromchargingrooms(seeFigure10.11.3).Directinciner-nuisanceiscausedbytheemissions.Afullyloadedchem-atorsaretheleastexpensivebutarelimitedintheirhourlyistryshouldprovideatleast0.25inofwaterdraft(262capacitiesto500lb,whileindirectincineratorsoperateatPa).Table10.11.5liststhediametersandheightsofchim-capacitiesupto1000lb/hr.Amanuallychargedinciner-neysaccordingtotheweightrateofwasteburnedinaator(seeFigure10.11.3)isfedthroughabell-coveredchutecontinuouslychargedmultiple-chamberincinerator.Thefromthefloorabovethefurnace.Thislabor-savingdesigntableassumesthattheincineratorusesnodilutionairandalsoguaranteesgoodcombustionefficiencyandprotectionagainstflashbacks.Theseparatechargingroomisalsocon-venientforsortingwasteforrecycling.Incineratorscanalsobefedfromthesamefloorwherethefurnaceislo-cated.Thisarrangementalsopermitssortingandislabor-efficientalthoughtheradiantheatcanbeuncomfortablefortheoperator.Inhigh-risebuildings,theinstallationofawastechuteeliminatesthelaborinvolvedinchargingtheincinerator(seeFigure10.11.4).Thechuteautomaticallydirectsthesolidwasteintoatop-charged,mechanicalincinerator.Thechargingratecanberegulatedbyrotarystarfeedersorbycharginggatesthatopenat15-to30-minintervals.Bothofferprotectionagainstmomentaryoverloading.FIG.10.11.4Incineratorwithautomaticchargingsystem.©1999CRCPressLLC thatthebreechingsbetweenthefurnaceandchimneyareofminimumlength.Theliningthicknessesshownareforoutdoorchimneys;chimneysinsidebuildingsneedaddi-tionalinsulation.Forproperincineratoroperation,thecoldairsupplytothefurnaceshouldnotberestricted.Inmostdesigns,thefurnacereceivesitsairsupplyfromtheincineratorroom.Theairsupplyshouldbesizedforabout15lbofairperlbofMSWburned.Iftheairsupplyisinsufficient,theme-chanicalventilationsystemofthebuildingcancausesmok-ingduetodowndrafts.Whenachimney’snaturaldraftisinsufficient,fansareinstalledtogeneratetherequireddraft.Inonsiteincinerators,theforced-draftairisusuallyintroducedunderfire.Introducingoverfireairtoimprovecombustionefficiencyisnotwidelyusedinonsiteunits.Whenthewasteiswetoritsheatingvalueislow,aux-iliaryfuelsareneededtosupportcombustion.Incontin-uouslychargedincinerators,theprimaryburnerissizedfor1500Btuperlboftype3wasteorfor3000Btuperlboftype4waste(seeTable10.11.2).Theheatcapacityofthesecondaryburnerisalso3000Btuperlbofwaste.Whentheincineratorisfullyloaded,thesecondaryburnerrunsforonlyshortperiodsatatime.FIG.10.11.5Incineratorcontrolsystem.Controlsburning.Insomeinstallations,thechargingsequenceisOnsiteincineratorsarefrequentlyoperatedautomaticallyalsoautomated.fromignitiontoburndown(seeFigure10.11.5).Thecy-cleisstartedbythemicroswitchonthechargingdoor,DomesticandMultiple-Dwellingwhichautomaticallystartsthesecondaryburner,thewa-terflowtothescrubber,andtheinduced-draftfan.WhenIncineratorsthedoorisclosed,theprimaryburnerisstartedandstaysDomesticincineratorsaresizedtohandleafewpoundsofonforanadjustabletimeofuptoanhouroruntilthesolidwasteperpersonperday.Insingledwellings,atyp-doorisreopened.Unlessinterruptedbyahigh-tempera-icalincineratorhasabout40,000Btu/hrofauxiliaryheattureswitch,thesecondaryburnerstaysonforuptofivecapacity.Becausedomesticincineratorsarelessefficienthours.Toprovideeachchargewiththesamepresetburn-thantheirmunicipalcounterparts,theamountofauxiliarydownprotection,thesecondaryburnertimerisreseteveryfuelusedishigh.ThedomesticincineratorinFiguretimethechargingdooropens.Bothburnershaveovertem-10.11.1hastwocombustionchambers.Themainpurposeperatureandflame-failuresafetycontrols.Also,aseparateofthesecondarychamberistoeliminatesmokeandodor.cycletimercontrolstheinduced-draftfanandscrubberwa-Asaresult,thepollutantemissionsfromdomesticincin-terflowtoguaranteeairflowandscrubbingactionduringeratorsarenotexcessive(seeTable10.11.6).Inmultipledwellings,themainpurposeofincinerationistoreducethevolumeoftheMSWpriortodisposal.Therefusefromadwellingof500residentsproducing2000TABLE10.11.5CHIMNEYSELECTIONANDSPECIFICATIONCHARTlb/dayofMSWatadensityof4lb/cuftfills100trashcans.Ifincineratedonsite,theresiduefitsinto10trashIncineratorcans.ChimneySizeCapacityIncineratorsinmultipledwellingscaneitherbechuteAllTypesInsideHeightaboveLiningSteelCasingfedorfluefed.Inthechute-feddesign,wasteisdischargedWaste,lb/hrDiameterGrateThicknessThicknessintothechuteandthenintotheincineratorfeedhopper0100–1501202692010ga.inthebasement(seeFigure10.11.4).Intheflue-feddesign0175–2501502692010ga.(seeFigure10.11.6),thechimneyalsoservesasthecharg-0275–3501803292010ga.ingchuteforthewaste,whichfallsontogratesabovean0400–5502103792As010ga.ashpitinsideaboxlikefurnace.Themainpurposeofthe0600–75024039930Af0chargingdooristoignitethewaste,whilethepurposeof0800–140030044930Af0theunderfireandoverfireairportsistomanuallysetthe1500–20003604993As0Af0airflowforsmokelessburning.Thewallsoftheincinera-©1999CRCPressLLC TABLE10.11.6INCINERATOREMISSIONS—TYPICALVALUESNewDomesticMunicipalIncineratorPollutantWastesIncineratorwithScrubberParticulates,grain/SCF0.01–0.200.03–0.40Carbonmonoxide,ppm200–1000,1000Ammonia,ppm,5—Nitrogenoxides,ppm2–524–58Aldehydes,ppm25–401–9FIG.10.11.7Retort-type,multiple-chamberincinerator.FIG.10.11.8Inlinemultiple-chamberincinerator.tureoftheretortincinerator(seeFigure10.11.7)isthemultiplechambersconnectedbylateralandverticalbreechings;thecombustiongasesmustpassthroughsev-eralU-turnsformaximummixing.Theinlinedesign(seeFigure10.11.8)alsoemphasizesgoodflue-gasmixing.Here,thecombustiongasesaremixedbypassingthroughFIG.10.11.6Flue-fedincinerator.90°turnsintheverticalplaneonly.Bothdesignsareavail-ableinmobilestylesforuseintemporaryapplicationstorconsistoftwobricklayerswithanairspacebetweensuchaslandclearanceorhousingconstruction.There-them.Theinnerlayerismadeof4.5inoffirebrickandtortdesignisforsmallerwaste-burningcapacities(underthe9-inouterlayerismadeofregularbrick.800lb/hr),whiletheinlinedesignisforhigherburningFlue-fedapartmentincineratorshaveadraft-controlrates.damperinthestack,rightabovethefurnace.ThisdamperRotaryincineratorsforburningsolidorliquidwastesispivotedandcounterweightedtoclosewhenachutedoorcanbecontinuousorbatchandcanbechargedmanuallyopenstochargerefuseintothefurnace.Asaresult,draftorbyautomaticrams.Theircapacitiesrangefrom100toatthefurnaceremainsrelativelyconstant.Towithstand4000lb/hr.Forburningwastethatcontainschlorinatedflameimpingement,thedraft-controldampershouldbeorganics,theincineratorchambermustbelinedwithacid-madeof20-gauge302stainlesssteel.resistantbrick,andthecombustiongasesmustbesentthroughabsorptiontowerstoremovetheacidicgasesfromthefluegas.MiscellaneousOnsiteIncineratorsSomeincineratordesignsarespeciallydevelopedforon-AdaptedfromMunicipalWasteDisposalinthe1990ssiteindustrialapplications.Theoutstandingdesignfea-byBélaG.Lipták(Chilton,1991).©1999CRCPressLLC 10.12PYROLYSISOFSOLIDWASTEPyrolysisisanalternatetoincinerationforvolumereduc-PyrolysisPrinciplestionandpartialdisposalofsolidwaste.AlargeportionofMSWiscomposedoflong-chainhydrocarbonaceousma-Anunderstandingoftheenergyrelationships,theeffectofterialsuchascellulose,rubber,andplastic.Thisorganicthermalflux,solidsize,andthetypesofequipmentisreq-materialrepresentsastorehouseoforganicbuildingblocksuisitetoanunderstandingofpyrolysisprinciples.thatcouldberetainedasorganiccarbon.Pyrolysisisaprocessthatislessregressivethanincinerationandrecov-ersmuchofthechemicalenergy.EnergyRelationshipsLong-chainorganicmaterialdisintegrateswhenex-Nosinglevalueexistsforthetotalenergyrequiredtopy-posedtoahigh-temperaturethermalfluxaccordingtotherolyzeanymaterial.Itdependsupontheproductsformedfollowingequation:whichdependonthetemperature,rateofheating,andsamplesize.Therefore,thereportedvaluesfortheheatofPolymericmaterial1Heatflux®aA(gas)pyrolysisconflictamongvariousexperimenters.1bB(liqui®)1cC(solid)10.12(1)Figure10.12.1expressesthegeneralenergyrequire-TheresultinggasincludesCO2,CO,H2,CH4,andvari-mentstopyrolyzeamaterialastheamountofoxygenousC2andC3saturatedandunsaturatedhydrocarbons.varies.ThelowersolidlinerepresentstheamountofheatTheliquidcontainsavarietyofchemicalcompounds,andaddedorremovedfromthesystem.Theuppersolidlinetheliquidrangesfromatarsubstancetoalightwater-representsthechemicalenergyofthepyrolysisproducts.solubledistillate.Thesolidisprimarilyasolidchar.Forpurepyrolysis,nooxygenisavailable,andallenergyTherelativeyieldofeachofthesegroupsofpyroly-forthepyrolysisreactionissuppliedfromindirectheat-sisproductsdependsonthechemicalstructureoftheing.Theheatrequiredisgivenbyq,whichrepresentsthesolidtobepyrolyzed,thetemperaturefordecomposi-heatnecessarytopyrolyzethesolidfeedandheattheprod-tion,theheatingrate,andthesizeandshapeofthema-uctstothepyrolysistemperature.ThevalueDH1repre-terial.sentsthechemicalenergyofthegas.AsoxygenismadeIftheproductsofpyrolysisreactwithoxygen,theyre-available,energyisreleasedwithinthesystem,andlessin-actaccordingtothefollowingequations:directenergyissupplied.A(gas)1O2®CO21H2O1heat10.12(2)B(liqui®)1O2®CO21H2O1heat10.12(3)C(soli®)1O2®CO21H2O1heat10.12(4)PurepyrolysisinvolvesonlythereactioninEquation10.12(1),thedestructivedistillationinanoxygen-freeat-mosphere.Thisdefinitioncanbeexpandedtoincludesys-temsinwhichalimitedamountofoxygenismadeavail-abletotheprocesstoreleaseenoughchemicalenergyforthepyrolysisreaction.Comparingtheresultsofvariousexperimentalinves-tigationsonpyrolysisisdifficultbecauseofthemanyvariablesinfluencingtheresults.Noreliabledesignmeth-odshavebeendevelopedthatallowforthescale-upoftheexperimentalresults.However,certainguidingprin-ciplesunderlyingallpyrolysissystemscanhelpinthese-lectionofaprocessthatmostlikelysatisfyaparticularneed.Theprocessandoperatingconditionsvarydependingupontherelativedemandforthechar,liquid,andgasfromFIG.10.12.1Generalenergyrequirementsforsolid–gasreac-theprocess.tionsasafunctionofoxygenavailability.©1999CRCPressLLC Atpoint2,anadiabaticconditionisreachedwheretheheatingarefardifferentthantheproductsobtaineddur-heatreleasedfromtheoxidationofaportionofthepy-ingrapidheating.Atveryslowheatingratestolowtem-rolysisproductscanfurnishtheenergyrequiredforthepy-peratures,themoleculehassufficienttimetobreakattherolysisreactionaswellastheenergynecessarytoheattheweakestlevelandreorganizeitselfintoamorethermallypyrolysisproducts,oxidationproducts,andnitrogentothestablesolidthatbecomesincreasinglyhardtodestroy.Onpyrolysistemperature.ThevalueDH2representsthetotalrapidheatingtoahightemperature,themoleculeexplodeschemicalenergyofthegasundertheseconditions.Theandformsarangeofsmallerorganicmolecules.largerfractionoftheenergygoestosensibleheatifnitro-Forthecellulosemolecule,slowheatingformshighchargenispresentandDH2issmaller.yieldsandlowgasandliquidyields.ThegasiscomposedAstheavailableoxygenincreases,heatmustberemovedprimarilyofCO,H2O,andCO2andhasalowheatingtomaintainaconstantreactiontemperature.Atpoint3,value.Forrapidheatingratesandhightemperature,thethestoichiometricoxygenforcompletecombustionisgasyieldincreasesandtheliquidissmaller.Thegasiscom-reached,andthereactionproductscontainnochemicalposedprimarilyofCO2,CO,H2,CH4,C2H2,andC2H4energy.Additionaloxygenactsonlyasacoolant;there-andhasareasonableheatingvalue.Forintermediateheat-fore,lessenergymustberemoveduntilpoint4isreached.ingratesandtemperatures,highliquidyieldsareobtained.Thispointiswherethefeedisbeingincineratedadiabati-ThegasproducediscomposedofmanyC1,C2,C3,andcally,andnoheatrecoveryispossible.ThisfigureshowsC4compoundsandhasahighheatingvalue.thatthecombinedenergyofthepyrolysisproductsisTable10.12.1showssomevaluesobtainedforpyroly-higherwhentheavailableoxygenisreduced.Anadvan-sisgasobtainedat1300and1600°Fataslowheatingratetageoftheoxygendependencyisthatiteliminatesthelim-inaretort.Forcomparisonthetablealsoshows1450°Fitationofpyrolysissystemsontherateofexternalheatde-pyrolysisatahighheatingrateinafluidizedbed.Bothmand.Whenenrichedoxygenisusedratherthanair,thesystemspyrolyzedMSW.fractionofenergytiedupinsensibleheatisless,leavingmorechemicalenergyinthepyrolysisproducts(thegreaterSolidSizethefractionofchemicalenergy).Foralargeretortrequiringindirectheating,thetimere-quiredtopyrolyzeabatchoftenexceedstwenty-fourEffectofThermalFluxhours.Theproductschangedrasticallyasthereactionpro-Theproductsresultingfromthethermaldestructionofhy-ceedsbecausealongtimeisneededforthecenterofthedrocarbonaceoussolidsdependuponthemaximumtem-batchtoreachthepyrolysistemperature.Themassnearperatureofpyrolysisandthetimeneededtobringthefeedthecentergoesthroughamuchslowerheatingcyclethantothistemperature.Theproductsformedduringslowthematerialnearthewalls.Fortheproducedgasandliq-TABLE10.12.1PYROLYSISPRODUCTSOFMSWCompositionofPyrolysisProductDataProductsSpeedofPyrolysisSlowSlowFastPyrolysisTemperature,138216521450°FWeight%Residue11.597.73.0Gas23.739.561.0Tar1.20.226.0LightOil0.9Liquor55.047.84.0Gas(Volume%)H230.951.937.16CO15.618.235.50CH422.612.711.10C2H62.050.14notC2H47.564.68measuredCO218.411.416.33Btu/ft563447366610Btu/ton5.427.936.36GasVolume,cuft/tn962017,30017,400©1999CRCPressLLC uidstobecollected,theymustpassthroughthicklayersthepyrolysischarfirstandtendstoburnthischartofur-ofpyrolysischar,andnumeroussecondaryreactionsre-nishtheheatforpyrolysis,whichreducesthecharyield.sult.Forthesereasons,thepyrolysisproductsofwoodIfairisintroducedparalleltothefeed,theoxygenreactsfromalargeretortcancontainmorethan120products.withtherawfeedandthepyrolysisgasandgivesalowerThesameconditionsaretrueforindividualparticles.gasyield.Foramaterialhavingthethermalpropertiesofwood,theRotaryequipment,however,ismoreexpensivetobuild,timerequiredforthecentertemperatureofaspheretoismoredifficulttodesignwithpositiveseals,andrequiresreachthesurfacetemperaturecanbegivenbythefollow-moremaintenance.ingequation:2t50.5r10.12(5)ShaftKilnwhereristheradiusininchesandtisinhours.Thisequa-Intheshaftkiln,thesolidsdescendthroughagasstream.tionindicatesthataboutonehourisneededforthecen-Theoxygenentersthebottomcountercurrentlytothefeedterofa3-inparticletoapproachthesurfacetemperature.andburnsthecharproductreachingthebottomoftheshaft.ThecombustiongasesproducedflowpastthesolidTypesofEquipmentfeedcausingpyrolysis.Thecharisusedtofurnishtheen-ergyforpyrolysis.ThisuseisundesirableifthecharisaSeveraltypesofequipmentareavailableforthepyrolysisvaluableproductand,inthatcase,thepyrolysisgascanofwaste.Thegeneraltypesincluderetorts,rotarykilns,beusedtopreheattheair.shaftkilns,andfluidizedbeds.Thetypeofequipmentandthemannerofcontactinghaveasignificanteffectonthepyrolysisproductyield.Fluidized-BedReactorTheretorthasthelongestapplicationhistoryandhasbeenusedextensivelytomakewoodcharcoalandnavalThefluidized-bedreactorisasystemwheretheheattrans-stores.Itisabatchsystemwheretheretortischarged,ferrateisrapid.Thisdesigngiveslowliquidyieldsandsealed,andheatedexternally.Theheatingcycleislong(of-highgasyields.Inthefluidizedbed,thefeedisinjectedtenovertwenty-fourhours).Theproductsarecomplex.intoahotbedofagitatedsolids.TokeepthebedintheTheyarenormallysolidcharandapyroligneousacidplusfluidstate,thesystempassesgasupwardthroughthebed.thegasproducedwhichisusedastheenergysourceforIfairisintroducedintothebed,theoxygencontactsandindirectheating.Theprocessislimitedbytherateofheatreactswiththepyrolysisgasmorereadilythanthecharaddition;atypicalanalysisfordemolitionlumbershowsdoes,reducingthegasyield.Toassurethattheproducedayieldof35%char,30%water,12%woodtar,5%aceticpyrolysisgasdoesnotreactwithoxygen,operatorscanacid,3%methanol,and15%gaswithaheatingvalueofremovethecharproducedandburnitinaseparateunit300Btu/cuft.andreturnthehotgasusedtopyrolyzethefeedintothefluidizedbed.Thecapacityislimitedbythesensibleheatavailablefromthisgas.Inafluidizedbed,circulatingtheRotaryKilnsolidsinthebedaddsheat.Theheatsourcenecessarytopyrolyzethefeedcanbeheatedsolidswhichcanbeeas-Therotarykilnismoreflexibleandprovidesincreasedilyaddedandremovedinthefluidizedbed.heattransfer.Thekilncanbeheatedindirectly,ortheheatcanbefurnishedbypartiallyburningthepyrolysisprod-ucts.ThegasflowcanbeeitherparallelorcountercurrentExperimentalDatatothewasteflow.Thegasandliquidproductsdonothavetoescapethroughthicklayersofcharasinthebatchre-LittledataispublishedonthepyrolysisofMSW,andnotort;therefore,fewercomplexsolid–gasreactionsoccur.dataispublishedforfull-scaleoperatingunits.ThedataTheheatcycleismuchfasterthanintheretort,andtheinTables10.12.1and10.12.2arebasedonsolidwastegasyieldishigherandtheliquidyieldlower.Thesizeoffromasmallpilotplantscaleorbenchscalelabexperi-theindirectlyfiredkiln,becauseofthehightemperaturesments.involvedandtheneedtotransferenergythroughthewalls,Table10.12.2presentstheyieldofvariousmaterialsisseverelylimited.Themaximumcapacityisintherangeexposedtoa1500°Ftemperature.Theyieldsofgas,liq-of2tnperhourforwoodwasteandissimilarforsoliduid,andcharvarywidelybetweenmaterials.Thefeedinwaste.allcasesisnewspaper,andthefinalpyrolysistemperatureIfalimitedamountofoxygenisusedastheenergyis1500°F.Anincreaseinthegasyieldandadecreaseinneededforpyrolysis,refractorylinedkilnscanbeused,liquidorganicsduetoanincreaseoftheheatingrateisev-andlargesystemsbecomefeasible.Iftheoxygenandtheidentfromthesedata.Thetotalamountofenergyavail-feedareintroducedcountercurrently,theoxygencontactsablefromthegasalsoincreaseswiththeheatingrate.©1999CRCPressLLC TABLE10.12.2PYROLYSISYIELDS,INWEIGHTPERCENTOFREFUSEFEEDPyrolysisProductsGasWaterCnHmOxCharC1SAshTypeofWasteFeedFordHardwood17.3031.9320.8029.540.43Rubber17.293.9142.4527.508.85WhitePineSawdust20.4132.7824.5022.170.14BalsamSpruce29.9821.0328.6117.313.07HardwoodLeafMixture22.2931.8712.2729.753.82NewspaperI25.8233.9210.1528.681.43II29.3031.3610.8027.111.43CorrugatedBoxPaper26.3235.935.7926.905.06BrownPaper20.8943.102.8832.121.01MagazinePaperI19.5325.9410.8421.2222.47II21.9625.9110.1719.4922.47LawnGrass26.1524.7311.4631.476.19CitrusFruitWaste31.2129.9917.5018.123.18VegetableFoodWaste27.5527.1520.2420.174.89Table10.12.1givestheproductsforaslowpyrolysisTABLE10.12.3FUELOILPRODUCTIONFROMprocessat1382and1652°Falongwithdataforfastpy-MSWrolysisat1450°F.TheincreaseingasyieldanddecreaseCharfraction,35wt%,heatingvalue9000Btu/lbinorganicliquidwithanincreaseinreactortemperatureCO48.8wt%areevident.ThehydrocarbonfractionofthegasdecreasesH3.9from32.2to17.5%withanincreaseintemperaturefromN1.11382to1652°F,whiletheH2andCOportionincreasesS0.03from46.5to70.1%.Thisdatashowsthathighertem-Ash31.8peraturepyrolysisgivessignificantlyhigheryieldstolowerCl0.2Btugas.ThehighertemperatureapparentlyresultsintheO(bydifference)12.7destructionofhydrocarbonsinthegas.ComparingvaluesOilfraction,40wt%,heatingvalue12,000Btu/lbforsolidwasteisdifficultbecauseofthevariabilitybe-C60%H8tweenfeedstocksofMSW.Table10.12.1showsthedataN1forarunat1450°FwherepyrolysisisrapidalongwithS0.2dataforslowpyrolysis.ThesedataindicatethatthefastAsh0.4pyrolysisat1450°FgivesresultswhichareclosertothoseCl0.3oftheslow,high-temperaturepyrolysisprocess.ThetotalO2(bydifference)20.0COandH2is72.6%,thetotalhydrocarbon10.1%1(un-Gasfraction,10wt%,heatingvalue600Btu/cuftdoubtedlyhigherbutonlyCH4isevaluated),andthegasH2O0.1mol%volume17,400cuft/tn.Unfortunately,thedataforfastCO42.0pyrolysisisnotcomplete,andafullcomparisonontheCO227.0yieldisnotpossible.H210.5Table10.12.3presentsdataforaprocesstoconvertCH3Cl,0.1MSWtofueloil.ThetemperatureforpyrolysisislowCH45.9C2H64.5(932°F),andthereactionraterapid.Thislow-temperatureC3–C78.9pyrolysisgiveshigheryieldsoforganicliquids,andthegasWaterfractioncontains:hassignificantquantitiesofC2–C7hydrocarbonsnotpre-Acetaldehydesentathighertemperatures.ReducingthetemperatureforAcetonethissameprocessbyseveralhundreddegreesresultsinanFormicacidincreaseinthegasyieldof80%.FurfuralThedataavailablesubstantiatetheguidingprinciplesMethanalpreviouslyoutlinedandexplainthecompositionandquan-MethylfurfuraltitiesoftheproductsandhowtheyareaffectedbychangesPhenolincomposition,temperature,andheatingrate.Theydo©1999CRCPressLLC GastoDryerPurificationandRecycleAsReceivedScreenRefuseAirWatertoClassifierPurificationandDisposalPyrolysisFineReactorGrindPrimaryShredderInorganicMagneticProcessingMetalsSubsystemUnrecoveredSolidstoDisposal—8wt%CharOilCleanAluminum~9000Btu/lb~4.8mmBtu/lbGlassFIG.10.12.2SchematicdiagramofOccidentalFlashPyrolysisSystemfortheorganicportionofMSW.(Reprinted,withpermission,fromG.T.Preston,1976,Resourcerecoveryandflashpyrolysisofmunicipalrefuse,presentedatInst.GasTechnol.Symp.,Orlando,FL,January.)notaccuratelypredicttheproductsfromaparticularwasmoredifficulttopumpandsmelledpoorly.Theseprocessorwaste.However,thedatadofurnishsufficientqualitiesresultedlargelyfromhighlyoxygenatedorganicsevidenceforenvironmentalengineerstosuggestthetype(includingacids).Furthermore,theoilproducedhadaofprocessforagivenapplication.moisturecontentof52%,notthe14%predictedfromthepilotplantresults.Theincreaseinmoistureintheoilde-creasedtheenergycontentto3600Btu/lb,comparedtoStatusofPyrolysisthe9100Btu/lbpredictedbythepilotplanttests.The100Pyrolysisiswidelyusedasanindustrialprocesstopro-tpdplantwasbuiltinElCajun,Californiabutneverranducecharcoalfromwood,cokeandcokegasfromwood,successfullyandwasshutdownafteronlytwoyearsofcokeandcokegasfromcoal,andfuelgasandpitchfromoperation.heavypetroleumfractions.Inspiteoftheseindustrialuses,Theprincipalcausesforthefailureofpyrolysistech-thepyrolysisofMSWhasnotbeenassuccessful.Nolarge-nologyappeartobetheinherentcomplexityofthesystemscalepyrolysisunitsareusedforMSWoperationintheandalackofappreciationbysystemdesignersofthedif-UnitedStatesasofApril30,1995.ficultiesofproducingaconsistentfeedstockfromMSWOnlyonefull-scaleMSWpyrolysissystemwasbuiltin(Tchobanoglous,Theisen,andVigil1993).theUnitedStates.AsimplifiedflowsheetoftheOccidentalAlthoughsystemssuchastheOccidentalFlashPyrolysisFlashPyrolysisSystemisshowninFigure10.12.2.TheSystemwerenotcommercialsuccesses,theyproducedfront-endsystemconsistsoftwostagesofshredding,airvaluabledesignandoperationaldatathatcanbeusedbyclassification,trommeling,anddryingtoproducefinelydi-futuredesigners.Iftheeconomicsassociatedwiththepro-videdRDF.BecauseoftheshortresidencetimeofRDFinductionofsyntheticfuelschange,pyrolysismayagainbethereactor,thisprocessisdescribedasflashpyrolysis.Theaneconomical,viableprocessforthethermalprocessingheatrequiredforthepyrolysisreactioninthereactorisofsolidwaste.However,ifgaseousfuelsarerequired,gasi-suppliedfromrecirculationofthehotchar.Thehotcharficationisasimpler,morecost-effectivetechnology.isremovedfromthereactor,passedthroughanexternalfluidizedbedinwhichsomeairisaddedtopartiallyoxi-dizethechar,andrecirculatedtofurnishenergyforthe—R.C.Bailie(1974)endothermicpyrolysisreactionwhichyieldstheliquidby-andDavidH.F.Liu(1996)products.Theendproductsweregases,pyrolyticoil,char,andresidues.TheliquidproducthadseveralnoxiousqualitiesReferencemakingitapoorsubstituteforBunkerCfueloil.ItwasTchobanoglous,G.,H.Theisen,andS.Vigil.1993.Integratedsolidwastecorrosive,requiringspecialstorageandfuelnozzles,andmanagement.McGraw-Hill,Inc.©1999CRCPressLLC 10.13SANITARYLANDFILLSThelandfillisthemostpopulardisposaloptionforMSWEMISSIONS,LEACHATE,ANDintheUnitedStates.NotonlyhasittraditionallybeentheMONITORINGleast-costdisposaloption,itisalsoasolidwastemanage-mentnecessitybecausenocombinationofreduction,re-GaseousEmissionscycling,composting,orincinerationcancurrentlymanageLandfillsproducegasescomprisedprimarilyofmethanetheentiresolidwastestream.Barringunforeseentechno-andcarbondioxide.Emissionsarecontrolledtoavoidex-logicaladvances,landfillswillalwaysbeneededtohandleplosiveconcentrationsofmethaneorabuild-upofland-residualwastematerial.fillgasesthatcanrupturethecoverlinerorkillcoverveg-etation.LandfilldesignandmonitoringmustensurethattheconcentrationofCH4islessthan25%ofthelowerLandfillRegulationsexplosionlimitinstructuresatornearthelandfillandlessthanthelowerexplosionlimitatthelandfillpropertySolidwastelandfillsarefederallyregulatedunderSubtitleboundary.DoftheResourceConservationandRecoveryActofAfinalruleannouncedbyEPAinMarch,1996requires1976(RCRA).Inthepast,landfillregulationwaslefttolargelandfillsthatemitvolatileorganiccompoundsinex-thediscretionoftheindividualstates.TheSolidWastecessof50megagrams(Mg)peryeartocontrolemissionsDisposalandFacilityCriteria,promulgatedbytheU.S.bydrillingcollectionwellsintothelandfillandroutingtheEPA,specifyhowMSWlandfillsaretobedesigned,con-gastoasuitableenergyrecoveryorcombustiondevice.Itstructed,operated,andclosedandwereimplementedinalsorequiresalandfill’ssurfacemethaneconcentrationto1993and1994.Thecriteriaweredevelopedtoensurebemonitoredonaquarterlybasis.Iftheconcentrationisthatmunicipallandfillsdonotendangerhumanhealthgreaterthan500partspermillion,thecontrolsystemmustandarebasedontheassumptionthatmunicipallandfillsbemodifiedorexpandedtoinsurethatthelandfillgasisreceivehouseholdhazardouswasteandhazardouswastecollected.Theruleisexpectedtoeffectonlythelargest4%fromsmallgenerators.Statesarerequiredtoadoptregu-oflandfillsintheUnitedStates.lationsatleastasstrictastheEPAcriteria.Althoughsomestateshadsomeacceptableregulationsinplace,manydidnot.TheEPAiscurrentlyconsideringcriteriafornon-haz-Leachateardousindustrialwastelandfills.Inmoststates,landfillsconstructedunderthenewreg-Leachateiswaterthatcontactsthewastematerial.ItcanulationsaremoreexpensivetoconstructandoperatethancontainhighconcentrationsofCOD,BOD,nutrients,pastlandfillsbecauseofrequirementsconcerningdailyheavymetals,andtraceorganics.Regulationsrequirecover,liners,leachatecollection,gascollection,monitor-leachatetobecollectedandtreatedtoavoidgroundoring,hazardouswasteexclusion,closureandpostclosuresurfacewatercontamination.Compositebottomlinersarerequirements,andfinancialassurances(tocoverantici-required,consistingofanHDPEgeomembraneatleast60patedclosureandpostclosurecosts).Someofthemajormilover2ftofcompactedsoilwithahydraulicconduc-27aspectsofthelandfillcriteriaarebrieflydescribedbelowtivityoflessthan1310cm/sec.However,equivalentnext(40CFRParts257–258).linersystemscanbeused,subjecttoapproval.Thecom-positelineriscoveredwithadrainagelayerandleachatecollectionpipestoremoveleachatefortreatmentandmain-LOCATIONRESTRICTIONStainahydraulicheadoflessthan1ft.Leachateisgener-allysentdirectlytoamunicipalwastewatertreatmentplantLocationrestrictionsexcludelandfillsfrombeingnearorbutcanbepretreated,recirculated,ortreatedon-site.withincertainareastominimizeenvironmentalandhealthimpacts.Table10.13.1summarizeslocationrestrictions.OtherlocationrestrictionsnotmentionedinthefederalSurfaceWaterdisposalcriteriabutfoundinotherfederalstateregula-tionsincludepublicwatersupplies,endangeredorthreat-Leachategenerationcanbereducedwhenwateriskeptenedspecies,scenicrivers,recreationorpreservationar-fromenteringthelandfill,especiallytheworkingface.eas,andutilityortransmissionlines.Surfacewatercontrolalsoreduceserosionofthefinal©1999CRCPressLLC TABLE10.13.1SITINGLIMITATIONSCONTAINEDINSUBTITLEDOFTHERCRAASADOPTEDBYTHEEPALocationSitingLimitationAirportsLandfillsmustbelocated10,000ftfromanairportusedbyturbojetaircraft,5000ftfromanairportusedbypiston-typeaircraft.Anylandfillsclosermustdemonstratethattheydonotposeabirdhazardtoaircraft.FloodplainsLandfillslocatedwithinthe100-yearfloodplainmustbedesignedtonotrestrictfloodflow,reducethetemporarywaterstoragecapacityofthefloodplain,orresultinwashoutofsolidwaste,whichwouldposeahazardtohumanhealthandtheenvironment.WetlandsNewlandfillscannotlocateinwetlandsunlessthefollowingconditionshavebeendemonstrated:(1)nopracticalalternativewithlessenvironmentalriskexists,(2)violationsofotherstateandlocallawsdonotexist,(3)theunitdoesnotcauseorcontributetosignificantdegradationofthewetland,(4)appropriateandpracticablestepshavebeentakentominimizepotentialadverseimpacts,and(5)sufficientinformationtomakeadeterminationisavailable.FaultareasNewlandfillunitscannotbesitedwithin200ftofafaultlinethathashadadisplacementinHolocenetime(past10,000years).SeismicNewlandfillunitslocatedwithinaseismicimpactzonemustdemonstratethatallcontaminantimpactzonestructures(liners,leachatecollectionsystems,andsurfacewatercontrolstructures)aredesignedtoresistthemaximumhorizontalaccelerationinlithifiedmaterial(liquidorloosematerialconsolidatedintosolidrock)forthesite.UnstableareasLandfillunitslocatedinunstableareasmustdemonstratethatthedesignensuresstabilityofstructuralcomponents.Theunstableareasincludeareasthatarelandslideprone,areinkarstgeologysusceptibletosinkholeformation,andareunderminedbysubsurfacemines.Existingfacilitiesthatcannotdemonstratethestabilityofthestructuralcomponentsmustclosewithinfiveyearsoftheregulation’seffectivedate.Source:DatafromG.Tchobanoglous,H.Theissen,andS.Vigil,1993,Integratedsolidwastemanagement:Engineeringprinciplesandmanagementissues(NewYork:McGraw-Hill).cover.Regulationsrequirepreventingflowontotheactiveentandtwodowngradient,shouldbemaintained,andtheportionofthelandfill(i.e.,theworkingface)duringpeakwellwatershouldbetestedatspecifiedintervals.Mostdischargefromthetwenty-five-yearstormoftwenty-four-siteshavemorethanthreewells;theapplicableregulationshourduration.Collectionandcontrolofwaterrunningvarybystate.Monitoringisconductedbefore,during,andofftheactiveareaduringthetwenty-five-yearstormofafterthelandfilloperatingperiod.Remedialactionisre-twenty-four-hourdurationisalsorequired.LandfillsquiredwhendowngradientwaterqualityissignificantlyshouldhavenodischargesthatviolatetheCleanWaterworsethanupgradientwaterquality.Act.ClosureandPostclosureDailyCoverToreduce,control,orretainleachate,gaseousemissions,Exposedwastemustbecoveredwithatleast6inofsoilandsurfacewater,landfilloperatorsmustclosetheland-attheendofeachoperatingday.Alternativecovers,suchfillproperlyandmaintainituntilwastematerialstabilizes.asfoamortemporaryblankets,canbeapprovedforuse.Theymustinstallandmaintainafinalcovertokeeprain-wateroutofthelandfillandestablishvegetationtoreduceHazardousWasteerosion.Thepostclosureperiodisthirtyyears,duringwhichallpreviouslymentionedregulationsmustbefol-Hazardouswasteshouldbekeptoutofthelandfillsothatlowed,erosionmustbecontrolled,andsitesecuritymustthequalityofleachateandgaseousemissionsisimproved.bemaintained.Landfilloperationsmusthaveaprogramfordetectingandpreventingthedisposalofregulatedhazardouswastes.FinancialAssuranceIncaseofbankruptcyorothercircumstances,facilitiesMonitoringmustbeclosedinapropermanner.Thefinancialcapa-Monitoringisdonetoidentify,quantify,andtrackcon-bilitytosafelyclosethefacilityatanytimeduringitsop-taminantsandtodeterminewhereandwhencorrectiveac-erationallifemustbemaintainedbytheoperatorinaman-tionshouldtakeplace.Atleastthreewells,oneupgradi-neracceptabletothegoverningagency.©1999CRCPressLLC SitingNewLandfillswetlands,andendangeredorthreatenedspeciesshouldbeminimized.SitinglandfillsonimpermeablesoilswithPropersitingofsanitarylandfillsiscrucialtoprovidingadeepwatertableavoidsgroundwaterimpacts.economicdisposalwhileprotectinghumanhealthandtheLANDUSE—Thelandaroundthepotentialsiteshouldbeenvironment.Thesitingprocessconsistsofthefollowingcompatiblewithalandfill.tasks(WalshandO’Leary1991a):LANDPRICEANDEASEOFPURCHASE—Apotentialsiteiseasiertopurchaseifitisownedbyoneorafewpar-•Establishinggoalsandgatheringpoliticalsupportties.•Identifyingfacilitydesignbasisandneed•Identifyingpotentialsiteswithintheregion•SelectingandevaluatingindetailsuperiorsitesESTIMATINGREQUIREDSITEAREA•Selectingthebestsite•ObtainingregulatoryapprovalBeforeattemptingtoidentifypotentiallandfillsites,plan-nersmustestimatethearearequirementofthelandfill.Goalsincludedelineatingtheregiontobeserved,facil-Landfillsizingisafunctionof:itylifetime,targettippingfees,maximumhaulingdistance,potentialusers,andlandfillservices.Politicalsupportis•Landfilllife(typicallyfivetotwenty-fiveyears)crucialtosuccessfulsiting.Becauseoppositiontoanew•Populationservedlandfillisalmostalwayspresent,strongpoliticalsupport•Wasteproductionperpersonperdayforanewlandfillmustexistfromthestartofthesiting•Extentofwastediversityprocess.Asolidwasteadvisorycouncil—madeupofin-•Shapeandheightofthelandfillterestedindependentcitizensandrepresentativesofinter-•Landfillareausedforbufferzone,offices,roads,estedgroups—shouldbeformedearlyintheprocess,ifscalehouse,andoptionalfacilitiessuchasMRF,onedoesnotalreadyexist.tiredisposalandstorage,composting,andconve-Thedesignbasisandneedsofalandfilldependontheniencecenterapplicableregulationsandtherequiredlandfillarea(whichAnumberofformulascanhelpdeterminetheacreageinturndependontheamountofwastetobehandledandrequiredforwastedisposal(Tchobanoglous,Theissen,andtherequiredlifetime).TheamountofwastetobehandledVigil1993;Noble1992).Thetotalannualwasteproduceddependsonthepresentandfuturepopulationservedbybythepopulationtobeservedbythelandfillforeachyearthelandfill,theprojectedpercapitawastegenerationrate,oftheexpectedlandfill’slifeisestimatedas:andtheprojectedrecycling,composting,andreductionrates.(365d/yr)PWg(12f)Vip5}}}10.13(1)Developinganewlandfillinvolvesfindingthemostsuit-ableavailablelocation.Themaincriteriainvolvedinsit-where:inganewlandfillare:Vip5annualin-placewastevolume(cuy®/yr)P5populationservedbylandfillinagivenyearSITESIZE—Thesiteshouldhavethecapacitytohandletheservicearea’sMSWforareasonableperiodoftime.Wg5wastegenerationinagivenyear(lb/person/d)f5fractionofwastestreamdivertedinagivenyearSITEACCESS—All-weatheraccessroadswithsufficientca-Cd5specificdensityofthewaste(lb/cuyd)pacitytohandlethenumberandweightofwastetrans-portvehiclesmustbeavailable.Populationpredictionsfortheyearsofexpectedland-HAULDISTANCE—Thisdistanceshouldbetheminimumfilloperationcanusuallybeobtainedfromlocalgovern-distancethatdoesnotconflictwithsocialimpactcrite-mentagencies.Thetotalamountofwastegeneratedinaria.communityperpersoncanbedevelopedfromwastechar-LOCATIONRESTRICTIONS—Theserestrictionsaresumma-acterizationstudies.StateornationaldatacanbeusedifrizedinTable10.13.1.Additionalorstricterconstraintsnootherdataareavailable.Dataonrecyclingtrendscanalsobeimposed.shouldbegatheredlocally.PHYSICALPRACTICALITY—Siteswith,forexample,surfaceAslandfillingcostsincrease,largerandheaviercom-waterorsteepslopesshouldbeavoided.pactorsarebecomingmorecommon,resultinginhigherLINERANDCOVERSOILAVAILABILITY—Thissoilshouldbecompaction.Compactiondensitiesachievedinlandfillsavailableonsite;Offsitesourcesincreaseconstructionvaryfromaround800toashighas1400lb/cuydde-andoperatingcosts.pendingonthetypeofcompactionequipmentused.ValuesSOCIALIMPACT—Sitinglandfillsfarfromresidencesandof1000to1200lb/cuydareoftenusedasestimates.avoidingsignificanttrafficimpactsminimizesthisim-Covermaterialaddstotheamountofmaterialplacedpact.inthelandfill,reducingthelandfill’seffectivevolume.ENVIRONMENTALIMPACT—TheeffectonenvironmentallyTypicalwaste-to-cover-soil-volumeratiosareintherangesensitiveresources,suchasgroundwater,surfacewater,of4:1to10:1.Avalueof5:1or4:1isoftenassumed,in-©1999CRCPressLLC dicatingthatforevery4or5cuydofwaste,1cuydofIfplannersdonotassumethatalloftheexcavatedsoilcoversoilisdeposited.Ina5:1ratio,thecover-soil-to-comesfromthelandfillexcavation,thentheirsolutionwasteratiois1dividedby5,or0.2.Incorporatingwastemustincorporatetheannualin-placewasteandsoilvol-andcoversoil,theannualin-placewasteandsoilvolumeume,theexcavatedlandfillvolume,theabovegroundland-is:fillvolume,andthecover-soil-to-wasteratio.Excavationsideslopesareoftenassumedtobe1:1butmaybemoreVap5Vip(11CR)10.13(2)gradual.Excavationbottomslopesareslightandcanbewhere:assumedlevelforthepurposeofinitialsizeestimates.Vap5annualin-placewasteandsoilvolume,includingwasteandcoversoil(cuyd/yr)EXCLUSIVEANDNONEXCLUSIVECR5cover-soil-to-wasteratioSITINGCRITERIASometimesplannersassumethatallofthecoversoilLandfillsitingcriteriacanbedividedintotwomaingroups:willcomefromthelandfillexcavation.Inthiscase,allofexclusiveandnonexclusivecriteria.Ifasitefailsanex-thesoilmaterialexcavatedfromthelandfillendsupintheclusivecriterion,itisexcludedfromconsideration.landfill.Withthisassumption,plannerscanestimatetheExclusivecriteriaincludefederal,state,orlocallocationareausingtheassumedshapeandheightofthelandfillrestrictionsorphysicalrestrictions.Exclusivecriteriacanabovegroundlevelandthesumoftheannualin-placebeappliedwithmapsandtransparentoverlays.Forex-wastevolumethelandfillexpectstoreceive.Heightregu-ample,aU.S.GeologicalSurvey(USGS)quadranglemaplationsaregenerallyincludedinstateorlocallandfillreg-canbeusedasthebasemap.Transparentoverlayswithulationsandvaryfromplacetoplace.darkenedrestrictedareascanbeplacedoverthebasemap,Thesimplestshapethatcanbeassumedisthecube.AasshowninFigure10.13.2.Areasthatremaincleararemorerealisticshapeistheflat-toppedpyramid.BothshapesareshowninFigure10.13.1.Thevolumeofthe2cubiclandfillisV5(H)(B),whereH5theheightand2B5thelengthofthebase.Thus,area5B5V/H.Thevolumeoftheflat-toppedpyramidlandfill,withasquarebaseand3:1sideslopes,is:223V5HB3:126HB3:1112H10.13(3)wherea3:1sideslopemeansthatforevery3fthorizon-talrun,thesloperises1ft.SolvingforBwiththequa-draticequationgives:ExclusionsMap246H64wHwVwwipw2w12wHwwB3:15}}}10.13(4)2HAirportsPlannerscandeterminetheareabysquaringB3:1.Theycantakethebufferzoneandareaneededforroads,facilities,FloodPlain2andlagoonsintoaccountbyincreasingBorB.If4:1sideslopesareused:Wetlands248H14wHwVwwipw2w21w.w33wHwwB4:15}}}10.13(5)UrbanAreas2HSurfaceWaterWaterSupplySourcesbaHABB(a)(b)USGSTopographicMapFIG.10.13.1Cubic(a)andpyramid(b)landfillshapes.FIG.10.13.2Exclusivecriteriamappingwithoverlays.©1999CRCPressLLC consideredpotentiallandfillsites.Ifinformationisavail-wellsshouldasitebeselected.Leachateattenuationisaableindigitizedformat,geographicalinformationsystemsfunctionofmechanicalfiltration;precipitationandcopre-(GIS)canbeusedtocompleteoverlayanalyses(Siddiquicipitation;adsorption,dilution,anddispersion;microbial1994).activity;andvolatilization,mostofwhichcanbeassessedAsmallnumberofpotentiallandfillsitesareselectedviaasubsurfaceinvestigation(O’LearyandWalsh1991c).fromtheareasthatremainaftertheexclusivecriteriaareTheapprovalprocesscanbedemanding.Applicationapplied.Thefinalselectionprocessusesnonexclusivecri-writersshouldworkcloselywithstatepermittingperson-teria,suchashydrogeologicalconditions,haulingdistance,nel,whocanofferguidanceonwhatisacceptable.Tokeepsiteaccessibility,andlanduse.Thisprocesscanbedonecostslow,plannersshouldstartthesitingprocesswiththeinoneortwosteps.considerationoflargeareasbasedonlimitedandreadilyIfdigitizeddataexistfortheentireregionunderinves-availableinformationandenditwiththeselectionofonetigation,plannerscanranktheremainingareasusingGISsitebasedondetailedinformationonasmallnumberofandanappropriatedecisionmakingmodel,suchasthesites.analyticalhierarchyprocess(Siddiqui1994;ErkutandAtsomepointduringtheselectionandpermittingofaMoran1991).Forexample,USGSsoilmapsareavailablenewlandfill,plannersholdatleastone,andperhapssev-indigitizedformatandincludedepthtowatertable,deptheral,publicmeetingstoensurethatpublicinputisobtainedtobedrock,soiltype,andslopealthoughinformationisconcerningtheselectionofthelandfillsite.Generallyallavailableonlydownto5ft.PlannerscanalsouseUSGSlandfillsitesinconveniencesomeportionofthelocalpop-digitizedmapstoidentifyurbanareas,riversandstreams,ulation,andthusmostsitesgeneratesomepublicopposi-andlanduse.tion.Thesitingprocessmustbeclear,logical,andequi-Ifareasareranked,plannersusethisinformation,alongtable.Thesiteselectedmustbethebestavailablesite.withnondigitizedinformationandfieldinspection,tose-However,evenifthebestsiteisselected,equityconsider-lectanumberofsitesfromthebestareas.Otherwise,plan-ationsmaynecessitateofferingcompensationtoresidentsnersselectanumberofsitesbasedonlyonnondigitizednearthesite.informationandsimplefieldassessmentswithouttheaidofarearankings.Onceanumberofsiteshavebeenidentified,plannersDesignshouldrankthesitesinascientificallyjustifiablemannerLandfilldesignisacomplexprocessinvolvingdisciplinesusingestablisheddecisionmakingmodelssuchasthean-suchasgeomechanics,hydrology,hydraulics,wastewateralyticalhierarchyprocedure,interactionmatrices,ormul-treatment,andmicrobiology.Designgoalscanincludethetiattributeutilitymodels(CampDresser&McKee1984;following(WalshandO’Leary1991c):Morrison1974;AnandalinghamandWestfall1988–89).Thisprocessidentifiesasmallnumberofsites,usuallyless•Protectionofgroundwaterqualitythanfour,toundergodetailedinvestigationsregardinghy-•Protectionofairqualitydrogeologiccharacteristicssuchasdrainagepatterns,geo-•Productionofenergylogicformations,groundwaterdepth,flowdirections,and•Minimizationofenvironmentalimpactnaturalqualityandconstructioncharacteristicsofsitesoils.•MinimizationofdisposalcostsInaddition,detailedinformationaboutexistinglanduse,•Minimizationofdumpingtimeforsiteusersavailableutilities,access,politicaljurisdictions,andland•Extensionofsitelifetimecostisgathered(WalshandO’Leary1991a).Plannersuse•Maximumuseoflanduponsiteclosurethisinformationtoselectthesiteforwhichregulatoryap-provalwillbesought.Plannersmustconsiderthefinaluseofthelandfillsitedur-Hydrogeologicinformationiscrucialtothefinalsitese-ingthedesignprocesstoensurethatlandfilldesignandlectionandhasmanyuses.Themainconsiderationistheoperationarecompatiblewiththeenduse.proximityofgroundwater,groundwatermovement,andTable10.13.2summarizesthesanitarylandfilldesignthepotentialforattenuationofleachateshoulditescapesteps.Table10.13.3summarizesthelandfilldesignfac-fromthelandfill.Theproximityofgroundwaterissimplytors.Procurementoftherequisitepermitscantakeseveralthedepthtothegroundwatertable.Measuringthepiezo-years,thusthedesignprocess,anintegralpartofanyap-metricelevationofthewatertableinanumberofwellsplication,shouldbestartedlongbeforethecurrentdis-onandaroundthepotentialsitedeterminesgroundwaterposaloptionisscheduledtoclose.movement.ThedirectionofflowisperpendiculartotheThedesignpackageincludesplans,specifications,ade-linesofconstantpiezometricelevation.Groundwatersignreport,anoperator’smanual,andcostestimatesmovementisimportant(1)toassessthepotentialforland-(WalshandO’Leary1991b).Animportantpartofland-fillcontaminationtoimpacthumanhealth,forexampleiffilldesignisthedevelopmentofmapsandplanswhichde-nearbydrinkingwaterwellsaredowngradientoftheland-scribethelandfill’sconstructionandoperation,includingfillsite,and(2)todeterminetheplacementofmonitoringthelocationmap,basemap,sitepreparationmap,devel-©1999CRCPressLLC TABLE10.13.2SANITARYLANDFILLDESIGNSTEPSopmentplans,crosssections,phaseplans,andthecom-pletedsitemap(WalshandO’Leary1991c).1.DeterminationofsolidwastequantitiesandcharacteristicsThelocationmapisatopographicmapwhichshowsa.Existingtherelationshipofthelandfilltosurroundingcommuni-b.Projectedties,roads,etc.Thebasemapusuallyhasascaleof1in2.Designoffillingareaa.Selectionoflandfillingmethodbasedonsiteto200ftandcontourlinesat2to5ftintervals.Itincludestopography,bedrock,andgroundwaterthepropertyline,easements,right-of-ways,utilitycorri-b.Specificationofdesigndimensions:cellwidth,length,dors,buildings,wells,controlstructures,roads,drainageanddepth;filldepth;linerthickness;interimcoverways,neighboringproperties,andlanduse.Thesiteprepa-thickness;andfinalcoverthicknessrationmapshowsfillandstockpileareasandsitefacili-c.Specificationofoperationalfeatures:methodofcoverties.Thelandfillshouldbedesignedsothattheexcavatedapplication,needforimportedsoilforcoverorliner,materialisusedquicklyascover.Developmentplansshowequipmentrequirements,andpersonnelrequirementsthelandfillbaseandtopelevationsandslopes.Crosssec-3.Designfeaturestionsatvariousplacesandtimesduringthelandfilllife-a.Leachatecontrolstimeshouldalsobedeveloped.Phaseplansshowtheor-b.Gascontrolsderinwhichthelandfillisconstructed,filled,andclosed.c.Surfacewatercontrolsd.AccessroadsThecompletedsitemapshowstheelementsofthepro-e.Specialworkingareasposedenduseandincludesthefinallandscaping.f.SpecialwastehandlingConstructiondetailsshouldbeavailabledetailingleachateg.Structurescontrols,gascontrols,surfacewatercontrols,accessroads,h.Utilitiesstructures,andmonitoringfacilities.i.ConveniencecenterEquallyimportantasthedesignmapsisthesitedesignj.Fencingreport,whichdescribesthedevelopmentofthelandfillink.Lightingsequence(WalshandO’Leary1991b).Thefourmajorel-l.Washracksementsofthedesignreportare:m.Monitoringfacilitiesn.Landscaping•Sitedescription4.Preparationofdesignpackage•Designcriteriaa.Developmentofpreliminarysiteplanoffillareasb.Developmentoflandfillcontourplans:excavationplans;•Operationalproceduressequentialfillplans;completedfillplans;fire,•Environmentalsafeguardslitter,vector,odor,surfacewater,andnoisecontrolsc.Computationofsolidwastestoragevolumes,coversoilrequirementvolumes,andsitelifed.DevelopmentoffinalsiteplanshowingnormalfillLandfillTypesareas;specialworkingareas(i.e.,wetweatherareas),Twotypesoflinedlandfillsareexcavatedandarea.Atleachatecontrols,gascontrols,surfacewatercontrols,excavatedlandfills,soilisexcavatedfromtheareawhereaccessroads,structures,utilities,fencing,lighting,wasteistobedepositedandsavedforuseasdaily,in-washracks,monitoringfacilities,andlandscapingtermediate,orfinalcover.Excavatedlandfillsarecon-e.Preparationofelevationplanswithcrosssectionsofexcavatedfill,completedfill,andphasedevelopmentstructedonsiteswhereexcavationiseconomicalandtheoffillatinterimpointswatertableissufficientlybelowthegroundsurface.Areaf.Preparationofconstructiondetails:leachatecontrols,landfillsdonotinvolvesoilexcavationandarebuiltgascontrols,surfacewatercontrols,accessroads,whereexcavationisdifficultorthewatertableisnearstructures,andmonitoringfacilitiesthesurface.Allcoversoilisimportedtoarealandfills.g.PreparationofultimatelanduseplanBothtypesoflandfillsarelined;theexcavatedlandfillonh.Preparationofcostestimatethebottomoftheexcavation,thearealandfillonthei.Preparationofdesignreportgroundsurface.j.PreparationofenvironmentalimpactassessmentIftheentireavailableareaislinedatthebeginningofk.Submissionofapplicationandobtainingrequiredpermitsalandfill’slife,thelargelinedareacollectsrainwaterforl.Preparationofoperator’smanualthelifeofthelandfill,generatingalargequantityofun-Source:DatafromP.WalshandP.O’Leary,1991,Landfillsiteplanprepa-necessaryleachate.Forthisreason,landfilllinersandration,WasteAge22,no.9:97–105andE.Conradetal.,1981,Solidwasteleachatecollectionsystemsareconstructedinphases.Eachlandfilldesignandoperationpractices,EPAdraftreport,Contractno.68-01-3915.phaseconsistsofconstrucingalinerandleachatecollec-tionsystemonaportionoftheavailablearea,depositingwasteinthelinedarea,andinstallingintermediatecover.Constructionofthenextphasebeginsbeforethecurrent©1999CRCPressLLC TABLE10.13.3LANDFILLDESIGNFACTORSFactorsRemarksAccessPavedall-weatheraccessroadstolandfillsite;temporaryroadstounloadingareasLandareaArealargeenoughtoholdallcommunitywasteforaminimumoffiveyears,butpreferablytentotwenty-fiveyears;areaforbufferstripsorzonesalsoLandfillingmethodBasedonterrainandavailablecover;mostcommonmethodsareexcavatedandarealandfillsCompletedlandfillFinishedslopesoflandfill,3or4to1;heighttobench,ifused,50to75ft;slopeofcharacteristicsfinallandfillcover,3to6%SurfacedrainageDrainageditchesinstalledtodivertsurfacewaterrunoff;3to6%grademaintainedonfinishedlandfillcovertopreventponding;plantodivertstormwaterfromlinedbutunusedportionsoflandfillIntermediatecoverUseofonsitesoilmaterialmaximized;othermaterialssuchascompostproducedmaterialfromyardwasteandMSWalsousedtomaximizethelandfillcapacity;typicalwaste-to-coverratiosfrom5to1to10to1FinalcoverMultilayerdesign;slopeoffinallandfillcover,3to6%Landfillliner,leachateMultilayerdesignincorporatingtheuseofageomembraneandsoilliners.Crossslopecollectionforleachatecollectionsystems,1to5%;slopeofdrainagechannels,0.5to1.0%.Sizeofperforatedpipe,4in;pipespacing,20ftCelldesignandEachday’swasteformsonecell;coveratendofdaywith6inofearthorotherconstructionsuitablematerial;typicalcellwidth,10to30ft;typicalliftheightincludingintermediatecover,10to14ft;slopeofworkingfaces,2:1to3:1GroundwaterAnyundergroundspringsdiverted;ifrequired,perimeterdrains,wellpointprotectionsystem,orothercontrolmeasuresinstalled.Ifleachateleakageoccurs,controlwithimpermeablebarriers,pumpandtreat,oractiveorpassivebioremediationLandfillgasLandfillgasmanagementplandevelopedincludingextractionorventingwells,managementmanifoldcollectionsystem,condensatecollectionfacilities,vacuumblowerfacilities,flaringfacilities,andenergyproductionfacilities;operatingvacuumlocatedatwellhead,10inofwaterLeachatecollectionMaximumleachateflowratesdeterminedandleachatecollectionpipeandtrenchessized;leachatepumpingfacilitiessized;collectionpipematerialsselectedtowithstandstaticpressurescorrespondingtothemaximumheightofthelandfillLeachatetreatmentPretreatmentdeterminedbasedonexpectedquantitiesofleachateandlocalenvironmentalandpoliticalconditionsEnvironmentalVadosezonegasandliquidmonitoringfacilitiesinstalled;up-anddowngradientrequirementsgroundwatermonitoringfacilitiesinstalled;ambientairmonitoringstationslocatedEquipmentNumberandtypeofequipmentbasedonthetypeoflandfillandthecapacityofrequirementsthelandfillFirepreventionOnsitewateravailable;ifnonpotable,outletsmustbemarkedclearly;propercellseparationpreventscontinuousburn-throughifcombustionoccursSource:DatafromG.Tchobanoglous,H.Theissen,andS.Vigil,1993,Integratedsolidwastemanagement:Engineeringprinciplesandmanagementissues(NewYork:McGraw-Hill).phaseisfilledsothatitisreadytoreceivewasteassoononlyonephase.Part(a)showsthelandfilljustbeforewasteasthecurrentphaseisfilled.Thelinersandleachatecol-isdeposited.Thelinerisinstalledatgradesthatcauselectionsystemsofadjacentphasesareusuallytiedtogether.leachatetoflowtowardleachatecollectionpipes.ThesizeoflandfillphasesdependsontherateatwhichGroundwatermonitoringwellsarealsoinstalled.Part(b)wasteisdepositedinthelandfill,localprecipitationrates,showsthesecondwasteliftofanoperatinglandfillcellbe-statepermittingpractice,andsitetopography.Atlandfillsingcreated.Eachliftconsistsofalayerofdailywastecells.receivinglargeamountsofwasteperday,phasesizecanEachdailycellconsistsofthewastedepositedduringasin-bechosensothatphaseconstructionequipmentisalwaysgleoperatingday.Dailycellsareseparatedbythecoverinuse.Assoonastheconstructionofonephaseends,con-soilappliedattheendofeachday.Tokeepthedailycoverstructionofthenextphasebegins.Smallerlandfillscan-andlittertoaminimum,operatorsshouldkeepthework-notoperatethisway.ingfaceassmallaspossible.Figure10.13.3showsseveralpointsinanormal,exca-Temporaryroadsonthelandfillallowtrucktrafficeasyvated,landfilllifetime,simplifiedbecausethelandfillhasaccesstotheworkingfaceofthelandfill.Duringwet©1999CRCPressLLC weather,useofaspecialeasyaccessareaforwastedis-tionofthetopofthelandfillisrelativelyflatbecauseheightposalmaybenecessary.limitationskeeplandfillsfrombeingpointedcones.Part(c)ofFigure10.13.3showsthecompletedlandfill.However,aslightslope(3to6%)ismaintainedtoen-Fiveliftsarecreated,thefinalcoverisinstalled,vegetationcouragerun-off.isestablished,andgascollectionwellsareinstalled.Landfillexcavationshaveslopingbottomsandsides.LeachateControlExcavatedsideslopesaregenerallynotmorethanaratioof1:1.Theirstabilitymustbechecked,typicallywithro-Waterbroughtinwiththewaste,precipitation,andsur-tationalorsliding-blockmethods.Bottomslopesaregen-facerun-oncanincreasetheamountofwaterintheland-erally1to5%.However,whenlandfillsarebuiltonslop-fill,calledleachate.Leachate,especiallyfromnewland-ingterrain,bottomslopescanbesteeper,requiringstabilityfills,canhavehighconcentrationsofCOD,BOD,analysisaswell.Operatorsmustalsocheckthestabilityofnutrients,heavymetals,andtraceorganics(Tchobano-thesyntheticlineronsteeperslopestoensurethatitdoesglous,Theissen,andVigil1993).Leachatethatcontactsnotsliportear.Thisanalysisisbasedonthefrictionforcedrinkingwatersuppliescanresultincontamination.Forbetweenthelinerandthematerialjustbelowtheliner.thisreason,linersandcollectionsystemsareusedtomin-Plannersshouldestimatethebearingcapacityofthesoilimizetheleachatethatescapesfromlandfills.Unlesstest-belowthelandfillandfuturesettlementtoensurethatingindicatesthatitisnotapollutant,collectedleachateisproblemsassociatedwithdifferentialsettlingdonotensuetreatedbeforebeingreleasedinacontrolledmannerintoafterwasteisdepositedinthelandfill.Finally,thepipestheenvironment.usedintheleachatecollectionsystemmustbeabletobearThefactorsaffectingleachategenerationareclimate,theweightofthewasteplacedontop.sitetopography,thefinallandfillcovermaterial,theveg-Thesideslopesofthetopofthelandfillaregenerallyetativecover,sitephasingandoperatingprocedures,andaratioof3:1or4:1.Largelandfillshavebenches,orter-thetypeofwastematerialinthefill(O’LearyandWalshraces,onthesideslopetohelpreduceerosionbyslowing1991c).Obviously,withallelseequal,themorerainfall,downwaterasitflowsdownthesides.Thecentralpor-themoreinfiltrationintothelandfillandthemoreleachate.Topographycanaffecttheamountofwaterenteringorleavingthelandfillsite.OnepurposeofthefinalcoverisLeachateCollectiontokeepwaterfromenteringthefill.Currentfederalregu-PipeMonitoringlationsrequirethefinalcovertohaveahydrauliccon-Wellductivityatleastaslowasthebottomcompositeliner.,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,Unlessexemptionsaremade,thisrequirementmeansthat,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,thefinalcovermustincludeageosyntheticlayer.Ifa,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,Liner,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,drainagelayerisincludedinthefinalcover,thislayerfur-,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,(a)therreducestheamountofwaterinfiltratingthefill.WorkingFaceVegetativecoveronthefinalcoverreducesinfiltrationbyinterceptingprecipitationandencouragingtranspiration.Asalreadymentioned,propersitephasingkeepsthe,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,amountofexposedlinerareasmall,thusreducingthecol-,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,lectionofrainwater.Finally,thewastedepositedinthe,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,landfillcontainssomewater,andtheresultingmoisture,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ@@@@@@@@@@@@@@@@@@@@@@@@@@@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,(b)Dailycontentvarieswithlocationandwastetype.Forexample,CellGasCollectionWellFinalCoverwastewatertreatmentplantsludgescontainsignificantLandscapingamountsofmoisture.PlannerscanestimatetheamountofDailyleachategeneratedbyalandfillusingwaterbalanceequa-CelltionsortheEPA’sHELPmodel(Tchobanoglous,Theissen,andVigil1993;O’LearyandWalsh1991c).,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,Leachatecontrolsarethefinalcover,thesurfacewater,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,controlsthatkeepwaterfromrunningontothelandfill,,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,Linertheliner,theleachatecollectionsystem,theleakdetection,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ,,,,,,,,,,,,,,,,,,,,,,,,,,,,Leachate(c)system,andtheleachatedisposalsystem.CollectionFIG.10.13.3Developmentofalandfill:(a)excavationandin-stallationoflandfillliner,(b)placementofsolidwasteinland-FINALCOVERANDSURFACEWATERfill,(c)cutawaythroughcompletedlandfill.(AdaptedfromG.CONTROLSTchobanoglous,H.Theissen,andS.Vigil,1993,Integratedsolidwastemanagement:Engineeringprinciplesandmanagementis-Thefinalcovercreatesarelativelyimpermeablebarriersues[NewYork:McGraw-Hill].)overthefillareawhichkeepsrainwaterfromentering.The©1999CRCPressLLC slope,soiltype,andvegetationdeterminethesurfacewa-speedthelateralflowofleachateonceitreachesthebot-terrun-offcharacteristicsofthesite.Plannerscandeter-tomofthelandfill,adrainagelayerisplacedoverthecom-minerun-offquantitiesandpeakflowsusingstandardhy-positeliner(seeFigure10.13.4).Thedrainagelayercandrologicrun-offtechniques,suchastherationalmethodbemadeofcoarsemediasuchassandorshreddedtires,orTR55.Thecontrolofsurfacerun-offgenerallyrequiresthoughgeonets(high-strengthgeosyntheticgridslessthanbermstobeconstructedaroundthefillarea,butdrainageAsinthickcapableoftransmittinghighquantitiesofwa-ditchescanalsobeused.Adetentionpondisgenerallyre-ter)arealsocommon.Geotextilesminimizecloggingofthequiredaswell.drainagelayersbyexcludingparticles.Drainagelayersslopetowardcollectionpipes,whichdirectleachateto-wardasumpordirectlyoutofthelandfill.Figure10.13.5showsatypicalleachatecollectionpipeLINERScrosssection.TheleachatecollectionpipeislaidinagravelAlandfillcanbethoughtofasabathtub.Linersmakethetrenchwrappedwithageotextilewhichallowswatertobottomandsidesofthelandfilllesspermeabletothemove-entertheleachatetrenchbutkeepsoutsmallparticlesthatmentofwater.Figure10.13.4showsatypicallinersys-couldclogthegravelorpipe.Leachatecollectiontrenchestem.Federalregulationscallforacompositeliner,con-layontopofthelinerandtravelalonglocalhydrauliclowsistingofanHDPEgeomembraneatleast60milthickpoints.Theleachatecollectionsystemcarriesleachateout(1000milequalsoneinch)over2ftofcompactedsoilofthelandfillcellthroughthelinerordumpsleachateinto27(clay)withahydraulicconductivityoflessthan1310asumpwhichispumpedoverthesideoftheliner.cm/sec.Equivalentorbetteralternativelinersystemsareapprovedinsomecases.LEACHATEDISPOSALSYSTEMSConstructingthesoillinerrequiresspreadingandcom-pactingimpermeablesoilinseverallifts,ensuringthattheLeachatecanbetreatedbyrecycling,onsitetreatment,orsoilcontainsnearoptimummoisturecontentandcom-dischargetoamunicipalwastewatertreatmentplant.pactionforminimumpermeability.CompactionisusuallyRecyclingleachateinvolvesreapplyingcollectedleachatedonewithlargevehicleswithsheepsfootwheels.Syntheticatornearthetopofthelandfillsurface,thusprovidingmembranesusedincompositelandfilllinersmustbeatadditionalcontactbetweenleachateandlandfillmicrobes.least60milthick.ThesemembranescanbedamagedbyRecyclingcanreduceBODandCODandincreasepH—heavyequipmentandaregenerallyprotectedwithacare-withsubsequentreductioninheavymetalsconcentrations.fullyappliedlayerofsand,soil,orMSW.GeotextilescanFurthermore,leachaterecyclingevenstheflowofleachatealsobeusedtoprotectgeosyntheticliners.thatisremovedfromthelandfillandcanenhancethesta-bilizationofthelandfill(O’LearyandWalsh,1991c).Onsitetreatmentcaninvolvephysical,chemical,orbio-COLLECTIONANDLEAKDETECTIONlogicaltreatmentprocesses.However,leachatefromre-SYSTEMScentlydepositedwasteisahigh-strengthwastewater.Justasabathtubhasadraintoremovebathwater,theFurthermore,leachatecharacteristicschangedramaticallylandfillhasamechanismtoremoveleachate.ThelinerinFigure10.13.3(a)isgradedtodirectanyleachatereach-ingthelinersurfaceintoaleachatecollectionsystem.LinerPerforatedsystemsarenotleakproof.Collectingleachateandre-LeachateCollectionProtectivemovingitfromthelandfillreducesthehydraulicheadonPipeSoilLayerGeotextiletheliner,thusreducingfluidflowthroughtheliner.ToFilterFabric,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Waste,,,,,,,,,,,,,,,,,,,,,,,,,,,,,ProtectiveLayer,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,(Soil),,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Geotextile,,,,,,,,,,,,,GeotextileFilterFabricSandDrainageDrainageLayerSyntheticLayer(Sand,tires,orgeonet)MembraneWashedGravelGeosyntheticCompacted(1.5–2in)ClayLayerBarrierLayer—ClayandGeomembrane(Keepswaterout,directsgasestowardFIG.10.13.5Leachatecollectionpipeandtrench.(Adaptedventingandcollectionsystem)fromG.Tchobanoglous,H.Theissen,andS.Vigil,1993,Integratedsolidwastemanagement:EngineeringprinciplesandFIG.10.13.4Linersystem.managementissues[NewYork:McGraw-Hill].)©1999CRCPressLLC overthecourseofthelandfill’slife.Consequently,treat-oreticalmaximumbasedonstoichiometryandaregener-mentprocessesshouldbecarefullydesignedandcon-allyintherangeof4000cuftpertnofwaste(O’Learystructed.Themostcommonoptionistouseanearbymu-andWalsh1991b).nicipalwastewatertreatmentplant.LeachateisusuallyLandfillgasmustberemovedfromlandfills.Thefinaltransportedtothefacilitybytankertruck,butapipelinecover,usedtokeepoutwaterandsupportvegetationforiseconomicinsomecases.Usingamunicipalwastewatererosioncontrol,cantraplandfillgases.Abuild-upofgastreatmentplanttotreatahigh-strengthwastewatermayinalandfillcanrupturethefinalcover.Inaddition,theinvolveextrachargesorpretreatmentrequirements.vegetativecovercanbekillediftheporespaceinthefinalcovertopsoilbecomessaturatedwithlandfillgases.Finally,methaneisexplosiveifpresentinsufficientconcentration,LEACHATEMONITORINGabove5%.Methanetravelingthroughthelandfillorsur-Thelastleachatecontrolelementismonitoring.Someland-roundingsoilscancollectatexplosiveconcentrationsinfillsuselysimeters,geosyntheticmembranesplacedinthenearbybuildings.Migrationdistancesgreaterthan1500ground,todetectandcollectmaterialdirectlyunderthefthavebeenobserved(O’LearyandWalsh1991a).Forlandfill.However,monitoringismostcommonlyaccom-thesereasons,landfillgasesmustbeventedorcollected.plishedbycollectinggroundwaterfromwellslocatedGascontrolcanbeaccomplishedinapassiveoractivearoundthelandfill,bothupgradientanddowngradientofmanner.Passivelandfillgascontrolreliesonnaturalpres-thelandfill.Upgradientwellsareimportantindetermin-sureandconvectiontoventgastotheatmosphereorflares.ingwhetherdowngradientcontaminationiscausedbythePassivesystemsconsistofgasventingtrenchesorwells,ei-landfillorsomeupgradientevent.Groundwaterismoni-therinthelandfilloraroundit.However,passivesystemstoredregularlyforanumberofinorganicandorganiccon-arenotalwayssuccessfulbecausethepressuregeneratedstituents(CFR40Parts257–258).Detectionofacontam-bygasproductioninthelandfillmaynotbeenoughtoinantatastatisticallysignificanthigherconcentrationthanpushlandfillgasout.backgroundlevelsresultsinincreasedmonitoringrequire-Activegascontrolremoveslandfillgasesbyapplyingaments.Detectionofcontaminantsatconcentrationsabovevacuumtothelandfill.Inotherwords,thelandfillgasesgroundwaterprotectionlevelsrequirestheoperatortoas-arepumpedout.However,overpumpingdrawsairintosesscorrectivemeasures.Basedonthisassessment,acor-thelandfill,slowingtheproductionofmoremethane.Afterrectivemeasureisselectedthatprotectshumanhealthandexpensivelandfillgasextractionequipmentisinstalled,theenvironment,attainstheapplicablegroundwaterpro-slowingmethaneproductionisnotdesirable.Ifmigrationtectionstandards,controlsthesource(s)ofreleasetothecontrolistheprimarypurposeofactivegascontrol,re-maximumextentpossible,andcomplieswiththeapplica-coverywellscanbeplacedneartheperimeteroftheland-blestandardsformanaginganywasteproducedbythefill.However,landfillgascanbeanenergysource,inwhichcorrectivemeasures.Correctivemeasuresmayinvolvecaseverticalorhorizontalrecoverywellsaretypicallypumpandtreat,impermeablebarriers,orbioremediation.placedinthelandfill.Landfillgaswith50%methanehasaheatingvalueof505Btu/standardcuft,abouthalfthatofnaturalgas(O’LearyandWalsh1991a).GasControlCollectedlandfillgascanbevented,burnedwithouten-Wastematerialdepositedinlandfillscontainsorganicma-ergyrecovery,ordirectedtoanenergyrecoverysystem.terial.Ifsufficientmoistureisavailable(morethan20%),indigenousmicrobesdegradethismaterial.Whilesufficientexternalelectronacceptorsareavailable,degradationisTABLE11.13.4TYPICALLANDFILLGASachievedthroughrespiratoryprocessesthatproducepri-COMPONENTSmarilycarbondioxideandwater.Invariably,oxygenisComponentPercentavailableatfirst,entrainedinthewasteduringcollection,transport,andunloading.Usually,microbialactivitycon-Methane47.4sumestheavailableoxygenwithinashortperiodoftime,Carbondioxide47.0i.e.,daysorweeks.IfalternativeelectronacceptorsareNitrogen3.7availabletosubstituteforoxygen,respiratoryprocessesOxygen0.8continue(Suflitaetal.1992).Themostcommonalterna-Paraffinhydrocarbons0.1tiveelectronacceptorinlandfillsissulfate,foundingyp-Aromatic-cyclichydrocarbons0.2Hydrogen0.1sumdrywalldebris.Hydrogensulfide0.01AlternativeelectronacceptorsarenotavailableinmostCarbonmonoxide0.1ofthevolumeofatypicallandfill;subsequently,fermen-Tracecompounds0.5tativeprocessespredominate,ultimatelyproducingland-fillgasthatisprimarilycarbondioxideandmethane(seeSource:DatafromR.Ham,1979,Recovery,processingandutilizationofgasfromsanitarylandfills,EPA600/2-79-001.Table11.13.4).Observedgasyieldsarelessthanthethe-©1999CRCPressLLC Whenenergyistoberecovered,thegascanbepipeddi-•Constructingfencingaroundtheperimeteroftherectlyintoaboiler,upgradedtopipelinequality,orcleanedlandfillanddirectedtoanonsiteelectricityengine-generator.The•Constructingagateandentrancesignaswellasfirsttwooptionsarefeasibleonlyifaboilerorgaspipelinelandscapingislocatednearthelandfill,whichisnotcommon.•Constructingaconveniencecenter,eitherforsmallBecauseoftheexplosiveandsuffocativepropertiesofvehiclestounloadwaste(tominimizetrafficatthelandfillgases,specialsafetyprecautionsarerecommendedworkingface)orforthecollectionofrecyclables(O’LearyandWalsh1991a):•Installinglittercontrolfences•Preparingconstructiondocumentation•Nopersonshouldenteravaultortrenchonalandfillwithoutcheckingformethanegasorwear-Anefficientlandfillisoperatedsothatvectors,litter,ingasafetyharnesswithasecondpersonstand-andenvironmentalimpactsareminimized,compactionisingbytopullhimtosafety.maximized,workersafetyisensured,andregulationsare•Anyoneinstallingwellsshouldwearasafetyropemetorexceeded.Regulationscontrolorinfluencemuchtopreventfallingintotheborehole.ofthedailylandfilloperation.Forexample,regulationsre-•Nosmokingisallowedwhilegaswellsorcollec-quiresomeorallofthefollowing:tionsystemsarebeingdrilledorinstalledorwhengasisventingfromthelandfill.•Trafficcontrol•Collectedgasfromanactivesystemshouldbe•Anoperatingplanclearedtominimizeairpollutionandapotential•Controlofpublicaccess,unauthorizedtraffic,lit-explosionandfirehazard.ter,dust,diseasevectors,anduncontrolledwastePersonnelenteringthelandfillthroughgascollectionman-dumpingholesmustcarryanairsupply.•MeasurementofallrefuseGasmonitoringwellsshouldbeplacedaroundtheland-•Controloffiresfillifmethanemigrationcouldthreatennearbybuildings.•MinimizationoftheworkingfaceareaGaswellsareusedtomeasuregaspressureandtorecover•Minimizationoflitterscatterfromtheworkinggasfromsoilporespace.Theexplosivepotentialofgasesareacanbemeasuredwithportableequipment.•Frequentcleaningofthesiteandsiteapproaches•6inofsoilcoveronexposedwasteattheendoftheoperatingday•SpecialprovisionstohandlebulkywastesSitePreparationandLandfill•SeparationofsalvageorrecyclingoperationsfromOperationtheworkingface•ExclusionofdomesticanimalsSitepreparationinvolvesmakingasitereadytoreceive•SafetytrainingforemployeesMSWandcaninclude(O’LearyandWalsh1991d):•Annualreportsanddailyrecordkeeping•Clearingthesite•RemovingandstockpilingthesoilLandfillequipmentfallsintofourgroups:sitecon-•Constructingbermsaroundthelandfillforaes-struction;wastemovementandcompaction;covermove-theticpurposesandsurfacewatercontrol.Bermsment,placement,andcompaction;andsupportfunctionsareusuallyconstructedaroundeachlandfillphase.(O’LearyandWalsh1991d).Conventionalearthmoving•Installingdrainageimprovement,ifnecessary.equipmentisusuallyusedinlandfillconstruction.Theseimprovementscanincludedrainagechan-However,specializedequipmentisrequiredforlinerin-nelsandalagoon.stallation.Thevehiclesthatbringwastetothelandfill•Excavatingfillareasasphasesarebuilt(onlyfordumpontheworkingface.Therefore,operatorsaccom-excavatedlandfills)plishwastemovementandcompactionatthelandfillby•Installingenvironmentalprotectionfacilities,in-movingandspreadingthewastearoundtheworkingfacecludingaliner,leachatecollectionsystem,gascon-andtravelingoveritseveraltimeswithheavyequipment,trolequipment,groundwatermonitoringequip-usuallycompactorsordozers.Ifsoilisusedascoverma-ment,andgasmonitoringequipmentterial,itistransportedusingscrapersortrucks.Iftrucks•Preparingaccessroadsareused,additionalequipmentisneededforloading.•Constructingsupportfacilities,includingaserviceCoversoilcompactionisdonebythesameequipmentthatbuilding,employeefacilities,weighscale,andfu-compactsthewaste.Theuseofanalternativecoverma-elingfacilitiesterial,suchasfoamorblankets,mayrequirespecialequip-•Installingutilities,includingelectricity,water,ment.Acommonsupportvehicleisthewatertruck,whichsewage,andtelephonereducesroaddustandcontrolsfires.Theselectionofland-©1999CRCPressLLC fillequipmentdependsonbudgetandthedailycapacitystabilizedwithvegetationassoonaspossibletoavoidero-ofthesite.sion.Operatorsshoulddeterminethesoilcharacteristicsbeforeplantingandaddlime,fertilizer,ororganicmatterasrequired.Thebulkdensityshouldbemeasured,and,iftoohigh,amended.Speciesshouldbechosenthatareland-Closure,Postclosure,andEndUsefilltolerant(Gilman,Leone,andFlower1981;Gilman,BoththedesignandoperationmustconsidertheclosureFlower,andLeone1983).Grassesandgroundcoversandpostclosureperiods,aswellastheenduse.Typicalshouldbeplantedfirst.Ifpossible,seedsshouldbeem-endusesincludegreenareas,parks,andgolfcourses.Asbeddedinthesoil.Treesorshrubs,ifused,shouldbephasesareclosed,thefinalorintermediatecovermaybeplantedonlyoneortwoyearsaftergrassesareplanted.Ifapplieddependingonwhetherthetopelevationofthegrassescannotsurviveonthelandfill,thesamewillbetruelandfillhasbeenreached.Verticalgasventsorrecoveryoftreesandshrubs.Themostcommonproblemsen-wellscanbeinstalledasthefinalelevationsarereached.counteredwithrevegetationoflandfillsurfacesarepoorHorizontalgasrecoverywellsareinstalledatspecifiedsoil,roottoxicity,lowoxygenconcentrationinthesoilheightintervalsasthephasesarefilled.Asthesideslopesporespace,lownutrientvalue,lowmoisturecontent,andofthelandfillarecompleted,manyaspectsoffinalclosurehighsoiltemperature.Operatorsshoulddevelopalandfillcanalsobecompleted,includingfinalcoverinstallationclosureplanwhichaddressescontrolofleachateandgases,andrevegetation.drainageandcoverdesign,andenvironmentalmonitoringFigure10.13.6showsatypicalfinalcovercrosssection.systems.ThepostclosureperiodiscurrentlyspecifiedbyThesurfacelayerconsistsoftopsoilandisusedtosup-regulationtobeatleastthirtyyearsafterclosure.Duringportvegetation.Thevegetationreduceserosionandaes-thistime,surfacewaterdrainagecontrol,gascontrol,theticallyimprovesthelandfill.Grassesarethemostcom-leachatecontrol,andmonitoringcontinue.Thegeneralmonvegetationused,butotherplantsareused,includingproblemsthatmustbeaddressedduringthisperiodaretrees.Justbelowthesurfacelayeristheoptionaldrainagethemaintenanceofrequiredequipmentandfacilities,thelayer,usedtominimizethehydraulicheadonthebarriercontrolandrepairoferosion,andtherepairofproblemslayer.Thedrainagelayercanbesandorageonetandisassociatedwithdifferentialsettlementofthelandfillsur-protectedfromcloggingbyageotextile.Thenextlayerisface.thehydraulicbarrier.Currentregulationsrequireittohaveahydraulicconductivityatleastaslowasthebottomliner.Therefore,thebarrierlayerusuallyincludesageomem-SpecialLandfillsbrane.Asubbaselayermaybenecessarytoprotectthebarrierlayer.ThedistinctionbetweenthemodernsanitarylandfillandFinalclosureinvolvesinstallingtheremainingfinalhazardouswastelandfillisblurred,exceptthelatterusu-cover,plantingtheremainingvegetation,andaddinganyallyhastwoorthreelinersystemsandmultipleleachatefencingrequiredtomaintainsitesecurity.Revegetationde-collectionsystems(O’LearyandWalsh1992a).Landfillspendsonanumberoffactors(O’LearyandWalsh1992b).similartothesanitarylandfillaresometimesbuilttohan-First,thecoversoilmustbedeepenoughtosustainthedlespecialwaste.Specialwasteishigh-volumewastethatplantedspecies.Grassesrequireatleast60cm,whiletreesisnothazardousandcanbeeasilyhandledseparatefromrequireatleast90cm.Thefinalcovertopsoilshouldbethemunicipalwastestream.Separatedisposalisadvantageousifadedicateddis-posalfacilityisrequired,thewasteisperceivedtohavespecialassociatedrisks,orthewastecarriesalowerriskthanMSW.AnexampleofawastewithspecialrisksisVegetation(Helpscontrolerosion)infectiouswastewhich,thoughrelativelyinnocuousintheGroundSurfaceground,mustbehandledwithspecialcaresothatdisposalSurfaceLayer(Supportsvegetation)facilityworkersarenotinfected.Inthiscase,adedicatedGeotextilefacilitymayberequiredforworkersafety.AnexampleofDrainageLayeralow-riskwasteisconstructionanddemolitionwaste.In(Drainswateroffbarrierlayer)thiscase,usingadisposalfacilitywithlowerperformanceBarrierLayer—ClayandGeomembranestandardscanreducedisposalcost.Thus,aspecialland-(Keepswaterout,directsgasestowardventingandcollectionsystem)fillisdedicatedtooneorafewclassesofspecialwastematerial.Examplesofspecialmaterialincludecoal-firedSubbase(Insomecasesasubbaseisrequiredtoprotectthegeomembrane)electricpowerplantash,MSWincineratorash,construc-tionanddemolitiondebris,infectiouswaste,asbestos,orWasteanynonhazardousindustrialwastesubjecttosubtitleDFIG.10.13.6Typicalfinalcover.regulations.©1999CRCPressLLC ConclusionGilman,E.,I.Leone,andF.Flower.1981.Theadaptabilityof19woodyspeciesinvegetatingaformersanitarylandfill.ForestScience27,no.IntheUnitedStates,thelandfillisthemostpopulardis-1:13–18.posaloptionforMSW.Traditionally,ithasbeentheleast-Morrison,T.H.1974.Sanitarylandfillsiteselectionbytheweightedrank-ingsmethod.Mastersthesis,UniversityofOklahoma,Norman,Okla.costdisposaloption,anditisalsoasolidwastemanage-Noble,G.1992.SitinglandfillsandotherLULUs.Lancaster,Pa.:mentnecessitybecausenocombinationofreduction,TechnomicPublishingCompany,Inc.recycling,composting,orincinerationcancurrentlyman-O’Leary,P.andP.Walsh.1991a.Landfillgas:Movement,control,andagetheentiresolidwastestream.Developinganewland-uses.WasteAge22,no.6:114–122.fillinvolvessitelocation,landfilldesign,sitepreparation,———.1991b.Landfillingprinciples.WasteAge22,no.4:109–114.———.1991c.Leachatecontrolandtreatment.WasteAge22,no.7:andlandfillconstruction.Locatinganewlandfillcanin-103–118.volvesignificantpublicparticipation.Federalregulations———.1991d.Sanitarylandfilloperation.WasteAge22,no.11:specifymanylocation,design,operation,monitoring,and99–106.closurecriteria.Theseregulationsreducetheincidenceof———.1992a.Disposalofhazardousandspecialwaste.WasteAge23,unacceptablepollutioncausedbylandfills.no.3:87–94.———.1992b.Landfillclosureandlong-termcare.WasteAge23,no.2:81–88.—J.W.EverettSiddiqui,M.1994.Municipalsolidwastelandfillsiteselectionusingge-ographicalinformationsystems.Mastersthesis,UniversityofOklahoma,Norman,Okla.Suflita,J.,C.Gerba,R.Ham,A.Palmisano,W.Rathje,andJ.Robinson.References1992.Theworld’slargestlandfill:Amultidisciplinaryinvestigation.Anandalingham,G.andM.Westfall.1988–1989.SelectionofhazardousEnvironmentalScienceandTechnology26,no.8:1486–1495.wastedisposalalternativeusingmulti-attributetheoryandfuzzysetTchobanoglous,G.,H.Theissen,andS.Vigil.1993.Integratedsolidanalysis.JournalofEnvironmentalSystems18,no.1:69–85.wastemanagement:Engineeringprinciplesandmanagementissues.CampDresser&McKeeInc.1984.CumberlandCountylandfillsitingNewYork:McGraw-Hill.report.Edison,N.J.Walsh,P.andP.O’Leary.1991a.Evaluatingapotentialsanitaryland-CFR40Parts257and258.FederalRegister56,no.196:50978–51119.fillsite.WasteAge22,no.8:121–134.Erkut,E.andS.Moran.1991.Locatingobnoxiousfacilitiesinthepub-———.1991b.Landfillsiteplanpreparation.WasteAge22,no.10:licsector:Anapplicationoftheanalytichierarchyprocesstothemu-87–92.nicipallandfillsitingdecision.Socio-EconomicPlanningSciences25,———.1991c.Sanitarylandfilldesignprocedures.WasteAge22,no.no.2:89–102.9:97–105.Gilman,E.,F.Flower,andI.Leone.1983.Standardizedproceduresforplantingvegetationofcompletedsanitarylandfill.EPA600/2-83-055.10.14COMPOSTINGOFMSWIntheUnitedStates,180milliontn,or4.0lbperpersonTheincreasingrateofgeneration,decreasinglandfillca-perdayofMSWweregeneratedin1988(U.S.EPA1990).pacity,increasingcostofsolidwastemanagement,publicTherateofgenerationhasincreasedsteadilybetween1960oppositiontoalltypesofmanagementfacilities,andcon-and1988,from88millionto180milliontnperday(U.S.cernsfortherisksassociatedwithwastemanagementhasEPA1990).Furthermore,theratecontinuestoincreaseledtotheconceptofintegratedsolidwastemanagement(SteutevilleandGoldstein1993).In1988,72%ofthe(U.S.EPA1988).IntegratedsolidwastemanagementrefersMSWwaslandfilled.Atthesametime,duetostrictfed-tothecomplementaryuseofavarietyofwastemanage-eralregulations,mainlytheRCRA,thenumberofland-mentpracticestosafelyandeffectivelyhandleMSWwithfillshasdecreased(U.S.Congress1989).Fortheprotec-minimalimpactonhumanhealthandtheenvironment.tionofhumanhealthandtheenvironment,oldlandfillsAnintegratedsystemcontainssomeorallofthefollow-arebeingclosedandnewonesmustbecarefullycon-ingcomponents:structed,operated,andmonitoredevenwhenthelandfillisclosed.ThusthecostofdisposingMSWbylandfilling•Sourcereductionhasgreatlyincreased.•Recyclingofmaterials©1999CRCPressLLC •Incinerationseparatelyinspecialcontainers.Yardwastecompostingis•Landfillingincreasingespeciallysincesomestates,asapartoftheirwastediversiongoals,arebanningyardwastefromland-TheU.S.EPArecommendsahierarchicalapproachtofills(Glenn1992).TheU.S.EPA(1989);StromandsolvetheMSWgenerationandmanagementproblems.Finstein(1985);andRichard,Dickson,andRowlandUsingthefourcomponentsofintegratedsolidwasteman-(1990)providedetaileddescriptionsofyardwastecom-agement,thehierarchyfavorssourcereduction,whichisposting.aimedatreducingthevolumeandtoxicityofwaste.SeparatedMSWreferstotheuseofmechanicalandRecyclingisthesecondfavoredcomponent.Recyclingdi-manualmeanstoseparatenoncompostablematerialfromvertswastefromlandfillsandincineratorsandrecoverscompostablematerialintheMSWstreambeforecom-valuableresources.Landfillsandincineratorsarelowerinposting.Themechanicalseparationprocessesinvolvease-thehierarchybutarerecognizedasnecessaryinthefore-riesofoperationsincludingshredders,magneticsepara-seeablefuturetohandlesomewaste.tors,andairclassificationsystems.ThesequenceisoftenEssentially,thegoalofintegratedsolidwastemanage-referredtoasfront-endprocessing.Front-endprocessingmentistopromotesourcereduction,reuse,andrecyclingpreparesthefeedstockforefficientcompostingintermsofwhileminimizingtheamountofwastegoingtoincinera-homogeneityandparticlesize.Front-endprocessingalsotorsandlandfills.Compostingisincludedintherecyclingremovestherecyclablecomponentsandthusinsuresacomponentofthehierarchy.Thissectiondiscussesthehigher-qualitycompostproductsincethematerialwhichcompostingofMSW.causesproductcontaminationisremoved.Still,significantamountsofmetalsandtraceamountsofhouseholdhaz-AerobicCompostinginMSWardouswasteareoftenfoundaftermechanicalseparation.ManagementForthisreason,source-separatedmaterialisthepreferredfeedstocktoproducethehighestqualitycompostproduct.TheorganicfractionofMSWincludesfoodwaste,paper,Ontheotherhand,compostingpartiallyprocessed,cardboard,plastics,textiles,rubber,leather,andyardcommingledMSWcandivertwastefromlandfillswhenwaste.Organicmaterialmakesupabouthalfofthesolidtheproductqualityisnottoodemanding.Thecompostwastestream(Henry1991)(seeSection10.5).Almostallcanalsobeusedasintermediatelandfillcover(Tchobano-organiccomponentscanbebiologicallyconvertedal-glous,Theissen,andVigil1993).Recently,aplanningthoughtherateatwhichthesecomponentsdegradevaries.guidewaspublishedformixedorganiccomposting(SolidCompostingisthebiologicaltransformationoftheorganicWasteCompostingCouncil1991).fractionofMSWtoreducethevolumeandweightoftheTheorganicfractionofMSWcanbemixedwithwaste-materialandproducecompost,ahumus-likematerialthatwatertreatmentplantsludgeforcomposting.Thisprocesscanbeusedasasoilconditioner(Tchobanoglous,iscommonlyknownascocomposting.Ingeneral,a2:1Theissen,andVigil1993).mixtureofcompostableMSWtosludgeisusedasthestart-CompostingisgainingfavorforMSWmanagementingpoint.Sludgedewateringmaynotbenecessary.(GoldsteinandSteuteville1992).ItdivertsorganicmatterWhileMSWcontainsahighpercentageofbiodegrad-fromlandfills,reducessomeoftherisksassociatedwithablematerial(yardwaste,foodwaste,andpaper),onelandfillingandincineration,andproducesavaluablemustdecidepriortocompostingwhethertokeeptheor-byproduct(compost).Atthepresenttime,twenty-oneganicmaterialseparatefromtheothercomponentsofMSWcompostingplantsareoperatingintheUnitedStatesMSWortobeginwithmixedMSWandextracttheor-(GoldsteinandSteuteville1992).Mostoftheseplantscom-ganicmateriallaterforcomposting.Forexample,yardpostamixedMSWwastestream.Thisnumberdoesnotwaste(particularlyleaves)isoftenkeptseparatefromtheincludealargernumberofoperationswhichdealsolelyrestofMSWandcomposted.Thisseparationallowseas-withorganicmaterial,primarilyfromcommercialestab-iercomposting(thanwithmixedMSW)andyieldsaprod-lishments(grocerystores,restaurants,andinstitutions)anductwithlowlevelsofcontamination.Thedisadvantageisthosefacilitiescompostingyardwaste.Finstein(1992)thatseparatecollectionofyardwasteisnecessary.statesthatover200suchyardwastefacilitiesareinNewJerseyalone.COCOMPOSTINGRETRIEVEDApplicationsofaerobiccompostingforMSWmanage-ORGANICSWITHSLUDGEmentincludeyardwaste,separatedMSW,commingledMSW,andcocompostingwithsludge.TheprinciplesofcompostingandadescriptionoftheprocesstechnologyarepresentedinSection7.43forsludgecomposting.Whilethefundamentalsofsludgecompost-SEPARATEDANDCOMMINGLEDWASTEingareapplicabletoMSWcomposting,severalsignificantYardwastecompostingincludesleaves,grassclippings,differencesexist.Themajordifferenceinvolvesprepro-bushclippings,andbrush.ThiswasteisusuallycollectedcessingwhenMSWiscomposted.AsshowninFigure©1999CRCPressLLC 10.14.1,receiving,theremovalofrecoverablematerial,notethatoverthepastfiftyyears,morethanfiftytypesofsizereduction,andtheadjustmentofwasteproperties(e.g.,proprietarycommercialsystemshavebeendevelopedandtheC:Nratioandtheadditionofmoistureandnutrients)appliedworldwide.Ingeneral,theyarevariationsoftheseareessentialstepsinpreparingMSWforcomposting.threebasictechniques.Obviously,differentpreprocessingstrategiesareneededforsource-separatedorganicMSWandyardwaste.Also,theMunicipalCompostingStrategiesdegreeofpreprocessingdependsonthetypeofcompost-ingprocessusedandthespecificationsforthefinalcom-Today,alargedegreeofpublicoppositiontoalltypesofpostproduct(Tchobanoglous,Theissen,andVigil1993).wastemanagementfacilitiesandconcernsfortherisksas-MSWcompostingemploysthesametechniquesassociatedwithwastemanagementexists.Composting,how-sludgecomposting:windrow,aeratedstaticpile,andin-ever,isoftenperceivedasasaferalternativetoeitherland-vesselsystems.Tchobanoglous,Theissen,andVigil(1993)fillingorincineration(Hyatt1991)andisrankedhigherCommingledMSWACollectionVehicleReceivingWindrow,AreaStaticPile,AirorIn-VesselFront-EndLoaderCompostingBulkyItemsManualRemovalofWhiteGoodsMaterialCardboardFront-EndLoader,MaturationConveyorSystemBagBreakerPostprocessingConveyorPaper,Plastics,ManualRemovalofGlass,AluminumRecyclableMaterialandTinCansCompostProductConveyorBrokenGlassScreeningOtherSmall(TrommelorDisk)ResidualMaterialConveyorShreddingConveyorDiskConveyorShreddingScreeningOversizeMaterialConveyorConveyorMagneticFerrousSeparationMaterialConveyorWaterNutrientsMixingOtherAdditivesAFIG.10.14.1Generalizedflowdiagramforthecompostingprocess.(Reprinted,withpermission,fromG.Tchobanoglous,H.Theissen,andS.Vigil,1993,Integratedsolidwastemanagement[NewYork:McGraw-Hill].)©1999CRCPressLLC intheintegratedsolidwastemanagementhierarchy.promotingsourcereductionandrecycling.Atleast50%Nonetheless,compostingfacilitiesmustbecarefullyoftheMSWstreamiscompostable.Compostingdivertsplannedandmanagedforsuccessfuloperation.ThekeythesematerialsfromlessbeneficialdisposalmethodsandelementsareelucidatedbytheSolidWasteCompostingprovidesamoreenvironmentallysoundMSWprogram.Council(1991)andinclude:Acentralissueisthetradeoffbetweencollectioneaseandmanagementconcerns.Sourceseparatedorganicsare1.Recoveryandpreparationofcompostableseasiertocompostandyieldacompostproductofhigher2.Compostingqualitybutrequireseparatecollection.Theuseofcom-3.Refiningpostingprocessesandthetypeofwastetobecomposted4.Goodneighborplanting(mixedMSWversussourceseparation)mustbeintegrated5.Positivecontroloflitter,dust,odors,noise,andrunoffintotheoverallwastemanagementplanforagivenregion.Thefirststepinvolvespreprocessing(aspreviouslyde-IntermsofmixedMSW,preprocessingisimportanttoob-scribed).Thisprocessingresultsinthepreparationofatainahigh-qualityproduct.Regardlessofthefinalcom-goodfeedstockforcompostingandtherecoveryofrecy-postuseorsourceoffeedstock,somedegreeofprepro-clables.Thesecondstepisthecomposting,whichmustbecessingisnecessarytopreparethefeedstockforproperlycontrolled(asdescribedinSection7.43).Refiningcomposting.Thispreprocessinginsuresproperparticleinvolvespostcompostingmanagement(e.g.,screening)tosize,moisturecontent,andnutritionalbalance.improveproductquality.Goodneighborplantingincludesacarefullyselectedsite,pleasingappearance,pavedaccess,—MichaelS.Switzenbaumparking,asecuresite,andacleansite.Thepositivecon-trolelementincludesthetreatmentofodorsandotheremissions,pathogenandtoxincontrol,air-bornedustReferencesmanagement,noisecontrol,andrun-offcontrol.Finstein,M.S.1992.CompostinginthecontestofmunicipalsolidwasteCompostquality,animportantissue,isafunctionofmanagement.EnvironmentalMicrobiology58:355–374.thephysical,chemical,andbiologicalcharacteristicsoftheGlenn,J.1992.Thechallengeofyardwastecomposting.BioCycle33,product.Intermsofphysicalaspects,goodcompostshouldno.9:30–32.bedarkincolor;haveuniformparticlesize;haveapleas-Goldstein,N.andR.Steuteville.1992.SolidwastecompostingintheUnitedStates.BioCycle33,no.11:44–47.ant,earthyodor;andbefreeofclumpsandidentifiableHenry,C.L.,ed.1991.Technicalinformationoftheuseoforganicma-contaminants,suchasglassfragmentsandpiecesofmetalterialsassoilamendments:Aliteraturereview.2ded.SolidWasteandplastic.ChemicalcharacteristicsincludenotonlytheCompostingCouncil.Washington,D.C.positivecontributionfromorganicandinorganicnutrients,Hyatt,G.W.1991.Theroleofconsumerproductscompaniesinsolidwhicharehelpfulforplantproduction,butalsothedetri-wastemanagement.ProceedingsoftheNortheastSolidWasteCompostingConference.Washington,D.C.:SolidWasteCompostingmentsassociatedwithheavymetalsandtoxicorganics.Council.Otherchemicalcharacteristicsincludeweedseeds,salts,Richard,T.L.,N.M.Dickson,andS.J.Rowland.1990.Yardwasteman-plantpathogens,andpossiblyhumanpathogens.Stabilityagement:AplanningguideforNewYork.Albany,N.Y.:N.Y.StateandmaturityaresignificantconcernsforcompostqualityDeptofEnvironmentalConservation.andprocesscontrol.SolidWasteCompostingCouncil.1991.Compostfacilityplanningguideformunicipalsolidwaste.1sted.Washington,D.C.Qualityisamajorcomponentofmarketingcompost,Steuteville,R.andN.Goldstein.1993.ThestateofgarbageinAmerica.andmarketingplaysakeyroleintheeffectivenessofanyBioCycle34,no.5:42–50.programtocompostwaste.Theprimaryobjectiveinfind-Strom,P.F.andM.S.Finstein.1985.LeafcompostingmanualforNewingamarketforcompostisfindinganenduseoftheprod-Jerseymunicipalities.Trenton,N.J.:RutgersUniversityandtheN.J.uct.SincecompostingsignificantlyreducesthevolumeofDeptofEnvironmentalProtection.Tchobanoglous,G.,H.Theissen,andS.Vigil.1993.IntegratedsolidMSW,evenifthecompostislandfilled(asintermediatewastemanagement.NewYork:McGraw-Hill.cover)thatusemayjustifyacompostingprogram.U.S.Congress,OfficeofTechnologyAssessment.1989.FacingAmerica’sHowever,thevalueofanyprogramincreaseswhenabet-trashproblem.Whatnextformunicipalsolidwaste?OTA-0-424.terenduseissecuredwhichfurtherreducestherequiredWashington,D.C.landfillspaceandrecoversaresource—asoilconditioner.U.S.EnvironmentalProtectionAgency(EPA).1988.Thesolidwastedilemma:anagendaforaction.Draftreport.EPA/530/SW-88-052.Whilecompostcanbesold,revenuefromcompostingis———.1989.Decisionmakersguidetosolidwastemanagement.asecondaryobjective.WhileoperatingacompostfacilityEPA/530-SW-89-072.forprofitfromcompostsalesispossible,thissituation———.1990.CharacterizationofmunicipalsolidwasteintheUnitedrarelyoccurs.Ofcourse,anyrevenuegeneratedfromcom-States:1990update.Executivesummary.EPA/530-SW-90-042A.postsalescanoffsettheprocessingcost.CompostingMSWorvariousportionsofthewastestreamisanimportantcomponentofintegratedsolidBibliographywastemanagement.TheuseofcompostingispartoftheAmericanSocietyforTestingandMaterials(ASTM).1989.Standardstrategyofminimizingincinerationandlandfillingwhilespecificationsforwasteglassasarawmaterialfor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