Presentation on theme: "Municipal Solid Waste: Disposal and Recovery"— Presentation transcript:
1 Municipal Solid Waste: Disposal and Recovery CHAPTER 21Municipal Solid Waste: Disposal and Recovery
2 An introduction to municipal solid waste Danehy Park is in North Cambridge, MassachusettsIts 50 acres hosts thousands of peopleA red light in the bathroom warns if methane has built upThe park is built on an old landfill that was once a blight on the neighborhoodIn the 1970s and 1980s, closing old landfills created a “solid waste crisis” that turned out to be temporaryMany have been converted to parks, golf courses, and nature preservesWe are running out of space to put all of our garbage
4 Solid wastes: landfills and combustions Municipal solid waste (MSW): total of all materials (trash, refuse, garbage) thrown away from homes and small businessesIt is collected by local governmentsIt is different from hazardous waste and nonhazardous industrial wasteNonhazardous industrial waste: generated by industriesDemolition and construction wastes, agricultural and mining wastes, sewage sludge, industrial wastesStates, not the EPA, oversee these wastes
5 Disposal of municipal solid waste The amount of MSW generated in the U.S. is increasingMore people, changing lifestyles, excessive packagingIn 1960, the average MSW was 2.7 lbs/person/dayIn 2007: 4.6 lbs/person/dayIn 2007, the U.S. generated enough garbage to fill 96,000 garbage trucks/dayWe generate huge amounts of MSW and it is harder to dispose of in an environmentally sound and healthy wayMSW varies depending on the generator, neighborhood, and time of year
7 Electronic Waste: A Growing Problem E-waste consists of toxic and hazardous waste such as PVC, lead, mercury, and cadmium.The U.S. produces almost half of the world's e-waste but only recycles about 10% of it.Figure 22-4
8 Whose job?Many local governments are responsible for collecting and disposing of MSWThey own trucks and hire workersOr contract with a private firmWho pays for the cost of waste pickup?TaxesPay-as-you-throw: charges by the amount of trashCollectors bill householdsState and federal regulations begin to apply at disposal
9 Past sins Until the 1960s MSW was burned and buried in dumps Smoldering dumps smelled and attracted flies and ratsIncineration (combustion facilities): burn waste completelyMay cause air pollutionOpen dumps and incinerators were phased outPublic pressure and air pollution lawsReplaced by landfillsIn the last 10 years, landfills and combustion have declinedRecycling has increasedPatterns of disposal differ in countries
11 Approaches to Pollution Management Human activity producing pollutantAltering human activity through education incentives and penalties to promote:Development of alternative technologiesAdoption of alternative lifestylesReducing, reusing, recyclingRelease of pollutant into environmentRegulating and reducing the pollutant at the point of emissions by:Setting and imposing standardsIntroducing measures for extracting the pollutant from waste emissionsLong-term impact of pollutant on ecosystemCleaning up the pollutant and restoring ecosystems by:Extracting and removing the pollutant from the ecosystemReplanting and restocking with animal populations
12 INTEGRATED WASTE MANAGEMENT We can manage the solid wastes we produce and reduce or prevent their production.Figure 22-5
13 LandfillsLandfill: waste is put on or in the ground and covered with earthMinimizing air pollution and verminBut managers did not understand ecology, the water cycle, or products of decompositionThey did not have regulations to guide themSo landfills were put on any cheap land outside of townNatural gullies, abandoned quarries, wetlands, old dumps
14 Secure landfillsSecure landfill: a reasonably safe landfill that is linedIt also has a leachate-removal systemIt is monitored and properly cappedBut the barriers are subject to damage and deteriorationSurveillance and monitoring systems are needed to prevent leakage
15 Pipes collect explosive methane as used as fuel When landfill is full,layers of soil and clayseal in trashTopsoilElectricitygeneratorbuildingSandClayMethane storageand compressorbuildingLeachatetreatment systemGarbageProbes todetectmethaneleaksPipes collect explosive methane as used as fuelto generate electricityMethane gasrecovery wellLeachatestoragetankCompactedsolid wasteGarbageGroundwatermonitoringwellLeachatepipesLeachate pumpedup to storage tankfor safe disposalSandSyntheticlinerLeachatemonitoringwellSandClay and plastic liningto prevent leaks; pipescollect leachate frombottom of landfillGroundwaterClaySubsoilFig , p. 532
18 Problems of landfills: leachate and groundwater pollution Leaching: chemicals dissolve in and are transported by waterLeachate: water with various pollutantsA “witches brew” of pollutantsOrganic matter, heavy metals, chemicalsCan enter groundwater aquifersAll states have, or will have, landfills contaminating groundwaterFlorida has 145 sites on the Superfund list (sites where groundwater contamination threatens human health)
19 Problems of landfills: methane Buried wastes undergo anaerobic decompositionProducing biogas (methane, CO2 and hydrogen)Biogas is highly flammableSeeping horizontally through soil, it can enter homes and cause explosionsSeeping to the surface, it kills vegetationBiogas can be captured, purified, and used as fuelIn 2008, commercial landfill gas produced electricity and gas for 1.4 million homesReducing greenhouse gas emissions and fossil fuel use
21 Problems of landfills: incomplete decomposition Plastics in MSW resist decompositionPetroleum-based polymers resist microbial digestionBiodegradable plastic polymers have been developedUsing cornstarch, cellulose, lactic acid, soybeansThey are more expensiveThey are used by organic manufacturing companiesEven biodegradable materials degrade very slowlyNewspapers buried 30 years ago are still readableDecomposition requires waterBut water produces toxic leachates
22 Problems of landfills: settling Waste settles as it compacts and decomposesBuildings have never been put on landfillsWhere landfills have been converted to playgrounds and golf courses, shallow depressions or deep holes are createdMonitoring the facility and using fill to restore a level surface solve the problem
23 Improving landfillsThe EPA upgraded siting and construction requirementsNew landfills are sited on high, stable ground above the water table, away from airportsWater drains into a leachate-collection systemTile, plastic liners, and compacted soil collect leachateThe fill is built up in the shape of a pyramid and capped with earthen material and soil and reseededThe site is surrounded by groundwater monitorsAbandoned landfills can become recreational facilitiesAttractive golf courses and wildlife preserves
25 Siting new landfillsBetween 1988 and 2007, landfills decreased from 8,000 to 1,754The EPA does not think capacity is a problemBut people don’t want landfills near themIt is hard to find areas to build new landfillsAny potential site is met with protests and lawsuitsLULU (locally unwanted land use); NIMBY (not in my backyard); NIMTOO (not in my term of office)BANANA (build absolutely nothing anywhere near anything)
26 Outsourcing Undesirable consequences of the siting problem Drives up costs of waste disposalInefficient and objectionable transfer to private landfillsTransfer of waste may occur across state or national linesResentment and opposition from citizens11 U.S. states export > 1 million tons/year (#1: New York)13 states import > 1 million tons/year (#1: Pennsylvania)Desirable consequences of siting problems: it encourages recycling and stimulates combustion of MSW
27 Advantages of combustion 89 U.S. facilities burn 32 million tons/year of MSWA waste reduction process, not disposalAsh must still be disposed ofCombustion reduces weight of trash by 70% and volume by 90%Fly ash contains most of the toxic substancesIt is landfilledBottom ash: is used as fill in construction or roadbedsConverted to concrete
28 More advantages of combustion No changes are needed in collection or people’s behaviorTwo-thirds of combustion facilities are waste-to-energy (WTE)Untreated MSW releases 35% as much energy as coal when burnedProducing electricity for 2.3 million homesWasted energy going to landfills equals 9.4 billion gallons of diesel oil/yearMany facilities add resource recoverySeparating and recycling materials before and after burning
29 Drawbacks of combustion Air pollution: has decreased through strict regulationsOdor pollution: plants are isolated from residential areasFacilities are expensive to buildSiting: facilities are located in industrial areasToxic ash must be disposed of in secure landfillsThe facility must have a continuous supply of MSWAgreements with municipalities decreases flexibility in waste management optionsThe process wastes energy and materialsCombine burning with recycling and recovery
30 An operating facilityA facility serving 1 million gets 3,000 tons of MSW/dayWaste comes in by rail and truckCommunities pay $65/ton tipping feesWaste processing is efficient: 80% is burned for energy12% is recovered; 8% is landfilledIf 1 million tons of MSW are processed40,000 tons of metals are recycledElectricity for 65,000 homes is generatedOpponents cite air pollution, traffic, and property values as concerns against WTE facilities
31 The Waste To Energy process Incoming waste is inspected and recyclables are removedShredders reduce waste particles to 6 inches or lessMagnets remove metals for recyclingWaste is blown into boilers for burningWater circulating through the boilers produces steam for electricityMetals are separated from bottom ashCombustion gases are treated to reduce emissionsFly ash and bottom ash are taken to landfills
33 Costs of municipal solid-waste disposal Costs of disposing of MSW are increasingDesign features of landfillsExpenses in acquiring sites and transportationTipping fees average $42/ton (but New York City’s is $263/ton—$1 billion/year!)One consequence: illegal dumpingSome towns charge $5/bag for MSW, $1/tire, etc.Wastes are appearing in many areasBuildings put padlocks on dumpstersMany states track down midnight dumpers
34 Better solutions: source reduction Source reduction: reducing waste at its sourceThe best solution for domestic wastesDesigning, manufacturing, purchasing, or using materials to reduce the amount/toxicity of trashU.S. waste has leveled off at 4.5 lbs/personDue to lifestyle changesMeasured by measuring consumer spending, which reflects goods and products that become trashIn 2000, 55 million tons did not go into the waste stream
35 Examples Reducing the weight of items Steel cans are 60% lighter than they used to beReducing paper waste via electronic communication, data transfer, the InternetReusing durable goods: reselling itemseBay, Craigslist, Freecycle NetworkDesigning products to last longer and be easier to repairStaying off of bulk mailing listsComposting yard wastes
37 The recycling solution More than 75% of MSW is recyclablePrimary recycling: the waste is recycled into the same materialRecycling newspapers into newspapersSecondary recycling: waste is made into different products that may or may not be recyclableRecycling newspapers into cardboard
38 Benefits of recycling Recycling saves energy and resources One ton of recycled steel saves 2,500 pounds of iron ore, 1,000 lbs of coal, 5,400 BTUs of energyRecycling decreases pollutionMaking recycled paper uses 64% less energy, creates 74% less air, and 35% less pollutionA recycling program that processes 1 ton of waste eliminates 620 lbs of CO2, 30 lbs of methane, 5 lbs of CO, 2.5 lbs of particulates
39 What gets recycled?Paper (47%): paper, cardboard, insulation, or is compostedGlass (28%): new containers, fiberglass or used in highway construction (glassphalt)Plastic (12%): carpet, clothes, irrigation drainage tiles, building materials, sheet plasticMetals: recycling aluminum (39%) saves 90% of the energy to make cans from oreSaves energy, creates jobs, reduces the trade deficitYard wastes (64%) are composted
41 Other items that are recycled Textiles (17%): strengthen recycled paper productsOld tires (35%): incorporated into highway asphaltOver 1 million tires/year are burned in combustion plantsPeople recycle out of environmental and economic motivationsThe Global Recycling Network is an information exchange promoting recycling and ecofriendly products
42 Municipal recyclingRecycling is the most direct and obvious way to become involved in environmental issuesAlmost every state has recycling goals, with varying degrees of success33.4% of MSW was recycled in 2007There is great diversity in recycling programsRecycling centers, curbside recycling, incentives, etc.
45 Successful recycling programs Have a strong incentive to recyclePAYT charges, but no charges for recyclingHave mandatory regulations, with warnings or sanctions for violatorsOffer curbside residential recycling60% of people in the U.S. have curbside programsHave drop-off sites for large items (e.g., sofas)Have ambitious, yet clear and feasible, recycling goalsInvolve local industriesHave an experienced, committed recycling coordinator
47 Economics of recycling Cities have different recycling ratesNew York City, 16%; San Francisco, 70%Recycling costs are often higher than alternativesMarkets fluctuate wildly; low tipping feesRecycling critics say that recycling must pay for itselfEnvironmental assessments should compare energy costs of recycling with costs of landfill or combustionLife cycle analysis: comparing energy costs of making products from recycled goods vs. from scratch
48 Recycling has taken a hit The 2008–2009 recession caused demand for recyclable products to plummetBerkeley, California received $200/ton for recyclables in 2008, but it got $35/ton in 2009But support for recycling is strongTwo-thirds of households will participate in curbside recyclingEven more recycle if a PAYT program exists or participants are rewardedDover, New Hampshire’s MSW went from 6 lbs/person (1991) to 2.3 lbs/person (1997)
49 Paper recycling Newspapers: the most important item that is recycled 78% of newspaper is recycledWhat is meant by “recycled paper”?Recycled paper: routinely recovered and rerouted back into processingPostconsumer recycled paper is what’s importantIt is almost impossible to tell recycled from virgin paperThe market is a critical factor in recycled paperIs there a demand?
50 The market for recycled paper The market for recycled paper fluctuates widelyDuring the late 1980s, municipalities had to pay to get rid of paperIn 1995, at $160/ton, paper was being stolen!In 1996, the market collapsedCities had to pay to have paper hauled awayBut it is still less expensive than paying tipping feesThere is a lively international trade in used paperForest-poor countries buy wastepaper
52 Glass recycling and bottle laws Most MSW glass: containers for beveragesThe U.S. drinks 28 billion gallons/yearMost drinks come in single-serve containers that are thrown awayGlass = 5.3% of MSW, but 50% of nonburnable MSWMining and manufacturing create pollutionHidden problems: litter, injuries, flat tires, etc.Bottle laws: require a deposit on all beverage containersRetailers must accept used containers and pass them on for reuse or recycling
53 Bottle laws Are fiercely opposed by beverage and container industries Cite lost jobs and higher costs of beveragesWell-financed lobbying has defeated bottle laws11 states have adopted bottle lawsJobs are gained and costs have not risenA high percentage of bottles is returnedThere is a marked reduction in litterA national bottling law has been unsuccessfulIt would increase recyclingIt would employ tens of thousands
54 Plastics recovery Plastics have a bad reputation They have a rapid throughput (packaging, diapers, etc.)The are conspicuous in MSW and litterThey do not decompose in landfillsBottled water: the number one “new” drink8.9 billion gallons were sold in the U.S. in 2007Only two states with bottle laws include bottled waterPeople pay 10,000 times more than for tap waterOnly 1 in 6 bottles is recycledBut there is a real market demand for plastic
55 PETE and HDPENumbers and letters on the bottom of plastic bottles tell the type of plastic polymer in the bottlePETE (polyethylene terephthalate): code 1Recycled into carpets, jackets, film, strapping, new PETE bottlesHDPE (high-density polyethylene): code 2Recycled into irrigation drainage tiles, sheet plastic, recycling binsRecycling plastic makes economic and environmental sense
56 Plastic bagsPlastic bags are everywhere: hanging from trees, blowing along highways, clogging sewers, in oceansKilling thousands of marine animals and turtles yearlyEach year, the U.S. uses 100 billion (world: 1 trillion!)Hard to recycle and almost indestructibleChina has banned ultrathin bagsSan Francisco banned plastic bags in 2007The plastic industry is fighting back with lawsuitsUse cloth, paper bags, or thicker plastic bags
57 Regional recycling options As landfills close and MSW is transferred to other places, transfer stations that transfer wastes to larger vehicles are set upMaterials recovery facilities (MRFs, “murfs”)Converted transfer stations567 MRFs in the U.S. handle 91,000 tons/dayAfter recyclables are collected by curbside collection or collecting stations, MSW is trucked to the MRFWorkers inspect and sort the MSW to prepare it for the recyclable-goods marketGlass, cans, paper, plastic
59 MRFs MRF’s advantages: economies of scale It produces a high-quality end product for recyclable materials marketPeople know where to bring their wastesSome MRFs use high technology to sort wasteMagnets, optical sensors, air sortersMixed waste processing facilities: less commonWaste is sorted for recovery of recyclables before being landfilled or combustedThe U.S. has 34 facilities handling 43,000 tons/day
60 Composting mixed waste and yard trimmings Some facilities compost MSW after removing large items and metalsCo-composting: mixing treated sludge with MSW provides bacteria and nutrientsFacilities are plagued with flies and fireThey may also be combined with a MRFYard-trimmings composting programs are more common3,500 U.S. programs handle 57,000 tons/day
61 Integrated waste management It is not necessary to use one method of handling MSWSource reduction, waste-to-energy, combustion, recycling, MRFs, landfills, composting all have rolesIntegrated waste management uses several processesWaste reduction: the U.S. produces the most wasteWe are a “throwaway society”True management of MSW begins at homeWasteWise: an EPA-sponsored program that partners with local governments, schools, corporationsPartners design their own waste-reduction programs
64 Waste disposal issues There will always be MSW Landfilling will decrease and more MSW will go to WTE combustion facilities and recyclingPolicy makers have opted for short-term solutions with low political costsResulting in long-distance hauling of MSWAreas required to handle their own trash will find suitable landfill sites and use the best technologiesPeople don’t want trash from other areasIt will take an act of Congress to address this problem
65 Recycling and reuse Recycling is the wave of the future Making more durable goods is overlooked and underutilizedBanning the disposal of recyclables in landfills and at combustion facilities makes senseMassachusetts bans yard wastes, metals, glass, paper, and plasticsA national bottle law would be a giant step forwardClosing the “recycling loop” would encourage recycling
66 Closing the recycling loop Set minimum postconsumer levels of recycled content for newsprint and glass containersRequire purchases of certain goods that include recycled productsEven if they are more expensiveRequire that all packaging be reusable or made of recycled materialsTax credits or incentives encourage the use of recycled or recyclable materials in manufacturingHelp develop recycling markets
67 Municipal Solid Waste: Disposal and Recovery CHAPTER 21Municipal Solid Waste: Disposal and RecoveryActive Lecture Questions
68 Review Question-1True or False: Municipal solid waste (MSW) is the same as hazardous waste.a. Trueb. False
69 Review Question-1 Answer True or False: Municipal solid waste (MSW) is the same as hazardous waste.a. Trueb. False
70 Review Question-2“Gas wells” in landfills tap into the ______ naturally produced within the landfill by the decomposition process.a. carbon dioxideb. oxygenc. methaned. water vapor
71 Review Question-2 Answer “Gas wells” in landfills tap into the ______ naturally produced within the landfill by the decomposition process.a. carbon dioxideb. oxygenc. methaned. water vapor
72 All of the following are drawbacks of combustion except Review Question-3All of the following are drawbacks of combustion excepta. air pollution.b. reduction of garbage volume.c. combustion facilities are expensive.d. combustion ash must be disposed of as hazardous waste.
73 Review Question-3 Answer All of the following are drawbacks of combustion excepta. air pollution.b. reduction of garbage volume.c. combustion facilities are expensive.d. combustion ash must be disposed of as hazardous waste.
74 Review Question-4The two recyclable plastics in most common use are ______ (code 2) and ______ (code 1).a. HDPE; PETEb. HDL; LDLc. MSW; MRFd. LDL; MSW
75 Review Question-4 Answer The two recyclable plastics in most common use are ______ (code 2) and ______ (code 1).a. HDPE; PETEb. HDL; LDLc. MSW; MRFd. LDL; MSW
76 a. recycling and composting. b. materials recovery facilities. Review Question-5Integrated waste management calls for having the following processes in operation:a. recycling and composting.b. materials recovery facilities.c. landfills.d. all of the above.
77 Review Question-5 Answer Integrated waste management calls for having the following processes in operation:a. recycling and composting.b. materials recovery facilities.c. landfills.d. all of the above.
78 Interpreting Graphs and Data-1 According to Fig. 21-3, most of the municipal solid waste in the United States is disposed bya. recycling.b. composting.c. burying in landfills.d. burning.
79 Interpreting Graphs and Data-1 Answer According to Fig. 21-3, most of the municipal solid waste in the United States is disposed bya. recycling.b. composting.c. burying in landfills.d. burning.
80 Interpreting Graphs and Data-2 According to Fig , in what year did MSW recycling begin to increase dramatically?a. 1965b. 1990c. 2000d. 2007
81 Interpreting Graphs and Data-2 Answer According to Fig , in what year did MSW recycling begin to increase dramatically?a. 1965b. 1990c. 2000d. 2007
82 Thinking Environmentally-1 The accumulation of televisions, computers, DVD players, cell phones, and the like has contributed to a new kind of waste calleda. techno-waste.b. EZ-waste.c. MSW.d. e-waste.
83 Thinking Environmentally-1 Answer The accumulation of televisions, computers, DVD players, cell phones, and the like has contributed to a new kind of waste calleda. techno-waste.b. EZ-waste.c. MSW.d. e-waste.
84 Thinking Environmentally-2 The type of material that contributes most to the municipal solid waste in the United States isa. wood.b. food waste.c. plastics.d. paper.
85 Thinking Environmentally-2 Answer The type of material that contributes most to the municipal solid waste in the United States isa. wood.b. food waste.c. plastics.d. paper.