© 2011 Pearson Education, Inc. CHAPTER 21 Municipal Solid Waste: Disposal and Recovery.

© 2011 Pearson Education, Inc.

CHAPTER 21

Municipal SolidWaste: Disposaland Recovery


An introduction to municipal solid waste• Danehy Park is in North Cambridge, Massachusetts• Its 50 acres hosts thousands of people

• A red light in the bathroom warns if methane has built up• The park is built on an old landfill that was once a blight

on the neighborhood

• In the 1970s and 1980s, closing old landfills created a “solid waste crisis” that turned out to be temporary• Many have been converted to parks, golf courses, and

nature preserves

• We are running out of space to put all of our garbage


From landfills to playing fields


Solid wastes: landfills and combustions

• Municipal solid waste (MSW): total of all materials (trash, refuse, garbage) thrown away from homes and small businesses• It is collected by local governments• It is different from hazardous waste and

nonhazardous industrial waste

• Nonhazardous industrial waste: generated by industries• Demolition and construction wastes, agricultural and

mining wastes, sewage sludge, industrial wastes• States, not the EPA, oversee these wastes


Disposal of municipal solid waste• The amount of MSW generated in the U.S. is

increasing• More people, changing lifestyles, excessive packaging

• In 1960, the average MSW was 2.7 lbs/person/day• In 2007: 4.6 lbs/person/day

• In 2007, the U.S. generated enough garbage to fill 96,000 garbage trucks/day

• We generate huge amounts of MSW and it is harder to dispose of in an environmentally sound and healthy way

• MSW varies depending on the generator, neighborhood, and time of year


U.S. MSW composition


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 22-4Figure 22-4


Whose job?

• Many local governments are responsible for collecting and disposing of MSW• They own trucks and hire workers• Or contract with a private firm

• Who pays for the cost of waste pickup?• Taxes • Pay-as-you-throw: charges by the amount of trash• Collectors bill households

• State and federal regulations begin to apply at disposal


Past sins• Until the 1960s MSW was burned and buried in

dumps• Smoldering dumps smelled and attracted flies and rats

• Incineration (combustion facilities): burn waste completely• May cause air pollution

• Open dumps and incinerators were phased out • Public pressure and air pollution laws • Replaced by landfills

• In the last 10 years, landfills and combustion have declined• Recycling has increased

• Patterns of disposal differ in countries


U.S. MSW disposal


INTEGRATED WASTE MANAGEMENT

• We can manage the solid wastes we produce and reduce or prevent their production.

Figure 22-5Figure 22-5


Landfills

• Landfill: waste is put on or in the ground and covered with earth• Minimizing air pollution and vermin

• But managers did not understand ecology, the water cycle, or products of decomposition• They did not have regulations to guide them

• So landfills were put on any cheap land outside of town• Natural gullies, abandoned quarries, wetlands, old

dumps


Secure landfills

• Secure landfill: a reasonably safe landfill that is lined• It also has a leachate-removal system• It is monitored and properly capped• But the barriers are subject to damage and

deterioration

• Surveillance and monitoring systems are needed to prevent leakage

© 2011 Pearson Education, Inc.Fig. 22-12, p. 532

Sand

When landfill is full,layers of soil and clayseal in trash

Methane storageand compressorbuilding

Leachatestoragetank

Leachatemonitoringwell

Groundwatermonitoringwell

Electricitygeneratorbuilding Leachate

treatment system

Methane gasrecovery well

Compactedsolid waste

Leachatepipes

Leachate pumpedup to storage tankfor safe disposal

GroundwaterClay and plastic liningto prevent leaks; pipescollect leachate frombottom of landfill

Topsoil

SandClaySubsoil

Probes todetectmethaneleaks

Garbage

Garbage

Syntheticliner

Sand

Clay

Pipes collect explosive methane as used as fuel to generate electricity


Secure landfill


New Orleans dump


Problems of landfills: leachate and groundwater pollution• Leaching: chemicals dissolve in and are transported

by water• Leachate: water with various pollutants• A “witches brew” of pollutants• Organic matter, heavy metals, chemicals• Can enter groundwater aquifers

• All states have, or will have, landfills contaminating groundwater• Florida has 145 sites on the Superfund list (sites

where groundwater contamination threatens human health)


Problems of landfills: methane

• Buried wastes undergo anaerobic decomposition• Producing biogas (methane, CO2 and hydrogen)

• Biogas is highly flammable• Seeping horizontally through soil, it can enter homes

and cause explosions• Seeping to the surface, it kills vegetation

• Biogas can be captured, purified, and used as fuel• In 2008, commercial landfill gas produced electricity

and gas for 1.4 million homes• Reducing greenhouse gas emissions and fossil fuel

use


Westminster landfill


Problems of landfills: incomplete decomposition • Plastics in MSW resist decomposition • Petroleum-based polymers resist microbial digestion

• Biodegradable plastic polymers have been developed• Using cornstarch, cellulose, lactic acid, soybeans• They are more expensive• They are used by organic manufacturing companies

• Even biodegradable materials degrade very slowly• Newspapers buried 30 years ago are still readable

• Decomposition requires water• But water produces toxic leachates


Problems of landfills: settling

• Waste settles as it compacts and decomposes• Buildings have never been put on landfills

• Where landfills have been converted to playgrounds and golf courses, shallow depressions or deep holes are created

• Monitoring the facility and using fill to restore a level surface solve the problem


Improving landfills• The EPA upgraded siting and construction

requirements• New landfills are sited on high, stable ground above

the water table, away from airports• Water drains into a leachate-collection system• Tile, plastic liners, and compacted soil collect leachate

• The fill is built up in the shape of a pyramid and capped with earthen material and soil and reseeded

• The site is surrounded by groundwater monitors• Abandoned landfills can become recreational facilities• Attractive golf courses and wildlife preserves


Features of a modern landfill


Siting new landfills

• Between 1988 and 2007, landfills decreased from 8,000 to 1,754

• The EPA does not think capacity is a problem• But people don’t want landfills near them• It is hard to find areas to build new landfills• Any potential site is met with protests and lawsuits

• LULU (locally unwanted land use); NIMBY (not in my backyard); NIMTOO (not in my term of office)• BANANA (build absolutely nothing anywhere near

anything)


Outsourcing• Undesirable consequences of the siting problem• Drives up costs of waste disposal• Inefficient and objectionable transfer to private landfills

• Transfer of waste may occur across state or national lines• Resentment and opposition from citizens• 11 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


Advantages of combustion

• 89 U.S. facilities burn 32 million tons/year of MSW• A waste reduction process, not disposal• Ash must still be disposed of

• Combustion reduces weight of trash by 70% and volume by 90%

• Fly ash contains most of the toxic substances• It is landfilled

• Bottom ash: is used as fill in construction or roadbeds• Converted to concrete


More advantages of combustion

• No changes are needed in collection or people’s behavior

• Two-thirds of combustion facilities are waste-to-energy (WTE)

• Untreated MSW releases 35% as much energy as coal when burned• Producing electricity for 2.3 million homes• Wasted energy going to landfills equals 9.4 billion

gallons of diesel oil/year

• Many facilities add resource recovery• Separating and recycling materials before and after

burning


Drawbacks of combustion• Air pollution: has decreased through strict

regulations• Odor pollution: plants are isolated from residential

areas• Facilities are expensive to build• Siting: facilities are located in industrial areas• Toxic ash must be disposed of in secure landfills• The facility must have a continuous supply of MSW• Agreements with municipalities decreases flexibility in

waste management options

• The process wastes energy and materials• Combine burning with recycling and recovery


An operating facility

• A facility serving 1 million gets 3,000 tons of MSW/day• Waste comes in by rail and truck• Communities pay $65/ton tipping fees

• Waste processing is efficient: 80% is burned for energy• 12% is recovered; 8% is landfilled

• If 1 million tons of MSW are processed• 40,000 tons of metals are recycled• Electricity for 65,000 homes is generated

• Opponents cite air pollution, traffic, and property values as concerns against WTE facilities


The Waste To Energy process

• Incoming waste is inspected and recyclables are removed

• Shredders reduce waste particles to 6 inches or less• Magnets remove metals for recycling• Waste is blown into boilers for burning• Water circulating through the boilers produces steam

for electricity• Metals are separated from bottom ash• Combustion gases are treated to reduce emissions• Fly ash and bottom ash are taken to landfills


Waste-to-energy combustion facility


Costs of municipal solid-waste disposal

• Costs of disposing of MSW are increasing• Design features of landfills• Expenses in acquiring sites and transportation• Tipping fees average $42/ton (but New York City’s is

$263/ton—$1 billion/year!)

• One consequence: illegal dumping• Some towns charge $5/bag for MSW, $1/tire, etc.• Wastes are appearing in many areas • Buildings put padlocks on dumpsters• Many states track down midnight dumpers


Better solutions: source reduction

• Source reduction: reducing waste at its source• The best solution for domestic wastes• Designing, manufacturing, purchasing, or using

materials to reduce the amount/toxicity of trash

• U.S. waste has leveled off at 4.5 lbs/person• Due to lifestyle changes

• Measured by measuring consumer spending, which reflects goods and products that become trash• In 2000, 55 million tons did not go into the waste

stream


Examples

• Reducing the weight of items• Steel cans are 60% lighter than they used to be

• Reducing paper waste via electronic communication, data transfer, the Internet

• Reusing durable goods: reselling items • eBay, Craigslist, Freecycle Network

• Designing products to last longer and be easier to repair

• Staying off of bulk mailing lists• Composting yard wastes


Waste reduction by reuse


The recycling solution

• More than 75% of MSW is recyclable• Primary recycling: the waste is recycled into the

same material• Recycling newspapers into newspapers

• Secondary recycling: waste is made into different products that may or may not be recyclable• Recycling newspapers into cardboard


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 energy

• Recycling decreases pollution• Making recycled paper uses 64% less energy, creates

74% less air, and 35% less pollution

• A 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


What gets recycled?

• Paper (47%): paper, cardboard, insulation, or is composted

• Glass (28%): new containers, fiberglass or used in highway construction (glassphalt)

• Plastic (12%): carpet, clothes, irrigation drainage tiles, building materials, sheet plastic

• Metals: recycling aluminum (39%) saves 90% of the energy to make cans from ore• Saves energy, creates jobs, reduces the trade deficit

• Yard wastes (64%) are composted


Deck made from Trex


Other items that are recycled

• Textiles (17%): strengthen recycled paper products• Old tires (35%): incorporated into highway asphalt• Over 1 million tires/year are burned in combustion

plants

• People recycle out of environmental and economic motivations• The Global Recycling Network is an information

exchange promoting recycling and ecofriendly products


Municipal recycling

• Recycling is the most direct and obvious way to become involved in environmental issues

• Almost every state has recycling goals, with varying degrees of success• 33.4% of MSW was recycled in 2007

• There is great diversity in recycling programs• Recycling centers, curbside recycling, incentives, etc.


State recycling rates


MSW recycling in the U.S.


Successful recycling programs

• Have a strong incentive to recycle• PAYT charges, but no charges for recycling

• Have mandatory regulations, with warnings or sanctions for violators

• Offer curbside residential recycling• 60% of people in the U.S. have curbside programs

• Have drop-off sites for large items (e.g., sofas)• Have ambitious, yet clear and feasible, recycling goals• Involve local industries• Have an experienced, committed recycling coordinator


Curbside recycling


Economics of recycling

• Cities have different recycling rates• New York City, 16%; San Francisco, 70%

• Recycling costs are often higher than alternatives• Markets fluctuate wildly; low tipping fees

• Recycling critics say that recycling must pay for itself• Environmental assessments should compare energy

costs of recycling with costs of landfill or combustion• Life cycle analysis: comparing energy costs of making

products from recycled goods vs. from scratch


Recycling has taken a hit

• The 2008–2009 recession caused demand for recyclable products to plummet

• Berkeley, California received $200/ton for recyclables in 2008, but it got $35/ton in 2009

• But support for recycling is strong• Two-thirds of households will participate in curbside

recycling• Even more recycle if a PAYT program exists or

participants are rewarded• Dover, New Hampshire’s MSW went from 6

lbs/person (1991) to 2.3 lbs/person (1997)


Paper recycling

• Newspapers: the most important item that is recycled• 78% of newspaper is recycled

• What is meant by “recycled paper”?• Recycled paper: routinely recovered and rerouted

back into processing• Postconsumer recycled paper is what’s important

• It is almost impossible to tell recycled from virgin paper

• The market is a critical factor in recycled paper• Is there a demand?


The market for recycled paper

• The market for recycled paper fluctuates widely• During the late 1980s, municipalities had to pay to

get rid of paper • In 1995, at $160/ton, paper was being stolen!• In 1996, the market collapsed• Cities had to pay to have paper hauled away• But it is still less expensive than paying tipping fees

• There is a lively international trade in used paper• Forest-poor countries buy wastepaper


Wastepaper exports


Glass recycling and bottle laws• Most MSW glass: containers for beverages• The U.S. drinks 28 billion gallons/year• Most drinks come in single-serve containers that are

thrown away

• Glass = 5.3% of MSW, but 50% of nonburnable MSW

• Mining and manufacturing create pollution• Hidden problems: litter, injuries, flat tires, etc.

• Bottle laws: require a deposit on all beverage containers• Retailers must accept used containers and pass them

on for reuse or recycling


Bottle laws

• Are fiercely opposed by beverage and container industries• Cite lost jobs and higher costs of beverages• Well-financed lobbying has defeated bottle laws

• 11 states have adopted bottle laws• Jobs are gained and costs have not risen• A high percentage of bottles is returned• There is a marked reduction in litter

• A national bottling law has been unsuccessful• It would increase recycling• It would employ tens of thousands


Plastics recovery

• Plastics have a bad reputation• They have a rapid throughput (packaging, diapers,

etc.)• The are conspicuous in MSW and litter• They do not decompose in landfills

• Bottled water: the number one “new” drink• 8.9 billion gallons were sold in the U.S. in 2007

• Only two states with bottle laws include bottled water• People pay 10,000 times more than for tap water• Only 1 in 6 bottles is recycled• But there is a real market demand for plastic


PETE and HDPE

• Numbers and letters on the bottom of plastic bottles tell the type of plastic polymer in the bottle

• PETE (polyethylene terephthalate): code 1• Recycled into carpets, jackets, film, strapping, new

PETE bottles

• HDPE (high-density polyethylene): code 2• Recycled into irrigation drainage tiles, sheet plastic,

recycling bins

• Recycling plastic makes economic and environmental sense


Plastic bags

• Plastic bags are everywhere: hanging from trees, blowing along highways, clogging sewers, in oceans• Killing thousands of marine animals and turtles yearly

• Each year, the U.S. uses 100 billion (world: 1 trillion!)

• Hard to recycle and almost indestructible• China has banned ultrathin bags• San Francisco banned plastic bags in 2007• The plastic industry is fighting back with lawsuits

• Use cloth, paper bags, or thicker plastic bags


Regional recycling options

• As landfills close and MSW is transferred to other places, transfer stations that transfer wastes to larger vehicles are set up

• Materials recovery facilities (MRFs, “murfs”)• Converted transfer stations • 567 MRFs in the U.S. handle 91,000 tons/day

• After recyclables are collected by curbside collection or collecting stations, MSW is trucked to the MRF• Workers inspect and sort the MSW to prepare it for

the recyclable-goods market• Glass, cans, paper, plastic


Materials recovery facility


MRFs

• MRF’s advantages: economies of scale• It produces a high-quality end product for recyclable

materials market• People know where to bring their wastes

• Some MRFs use high technology to sort waste• Magnets, optical sensors, air sorters

• Mixed waste processing facilities: less common• Waste is sorted for recovery of recyclables before

being landfilled or combusted• The U.S. has 34 facilities handling 43,000 tons/day


Composting mixed waste and yard trimmings• Some facilities compost MSW after removing large

items and metals• Co-composting: mixing treated sludge with MSW

provides bacteria and nutrients• Facilities are plagued with flies and fire• They may also be combined with a MRF

• Yard-trimmings composting programs are more common• 3,500 U.S. programs handle 57,000 tons/day


Integrated waste management

• It is not necessary to use one method of handling MSW• Source reduction, waste-to-energy, combustion,

recycling, MRFs, landfills, composting all have roles• Integrated waste management uses several processes

• Waste reduction: the U.S. produces the most waste• We are a “throwaway society”• True management of MSW begins at home

• WasteWise: an EPA-sponsored program that partners with local governments, schools, corporations• Partners design their own waste-reduction programs


The throwaway society


Pay-as-you-throw trash pickup


Waste disposal issues

• There will always be MSW• Landfilling will decrease and more MSW will go to

WTE combustion facilities and recycling

• Policy makers have opted for short-term solutions with low political costs• Resulting in long-distance hauling of MSW

• Areas required to handle their own trash will find suitable landfill sites and use the best technologies• People don’t want trash from other areas• It will take an act of Congress to address this problem


Recycling and reuse

• Recycling is the wave of the future• Making more durable goods is overlooked and

underutilized• Banning the disposal of recyclables in landfills and at

combustion facilities makes sense• Massachusetts bans yard wastes, metals, glass,

paper, and plastics

• A national bottle law would be a giant step forward• Closing the “recycling loop” would encourage

recycling


Closing the recycling loop

• Set minimum postconsumer levels of recycled content for newsprint and glass containers

• Require purchases of certain goods that include recycled products• Even if they are more expensive

• Require that all packaging be reusable or made of recycled materials

• Tax credits or incentives encourage the use of recycled or recyclable materials in manufacturing

• Help develop recycling markets


CHAPTER 21

Municipal SolidWaste: Disposaland Recovery

Active Lecture Questions


True or False: Municipal solid waste (MSW) is the same as hazardous waste.

a. True

b. False

Review Question-1


True or False: Municipal solid waste (MSW) is the same as hazardous waste.

a. True

b. False

Review Question-1 Answer


“Gas wells” in landfills tap into the ______ naturally produced within the landfill by the decomposition process.

a. carbon dioxide

b. oxygen

c. methane

d. water vapor

Review Question-2


“Gas wells” in landfills tap into the ______ naturally produced within the landfill by the decomposition process.

a. carbon dioxide

b. oxygen

c. methane

d. water vapor



All of the following are drawbacks of combustion except

a. air pollution.

b. reduction of garbage volume.

c. combustion facilities are expensive.

d. combustion ash must be disposed of as hazardous waste.

Review Question-3


All of the following are drawbacks of combustion except

a. air pollution.

b. reduction of garbage volume.

c. combustion facilities are expensive.

d. combustion ash must be disposed of as

hazardous waste.



The two recyclable plastics in most common use are ______ (code 2) and ______ (code 1).

a. HDPE; PETE

b. HDL; LDL

c. MSW; MRF

d. LDL; MSW

Review Question-4


The two recyclable plastics in most common use are ______ (code 2) and ______ (code 1).

a. HDPE; PETE

b. HDL; LDL

c. MSW; MRF

d. LDL; MSW



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.

Review Question-5


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.



According to Fig. 21-3, most of the municipal solid waste in the United States is disposed by

a. recycling.

b. composting.

c. burying in landfills.

d. burning.

Interpreting Graphs and Data-1


According to Fig. 21-3, most of the municipal solid waste in the United States is disposed by

a. recycling.

b. composting.

c. burying in landfills.

d. burning.

Interpreting Graphs and Data-1 Answer


According to Fig. 21-11, in what year did MSW recycling begin to increase dramatically?

a. 1965

b. 1990

c. 2000

d. 2007

Interpreting Graphs and Data-2


According to Fig. 21-11, in what year did MSW recycling begin to increase dramatically?

a. 1965

b. 1990

c. 2000

d. 2007

Interpreting Graphs and Data-2 Answer


The accumulation of televisions, computers, DVD players, cell phones, and the like has contributed to a new kind of waste called

a. techno-waste.

b. EZ-waste.

c. MSW.

d. e-waste.

Thinking Environmentally-1


The accumulation of televisions, computers, DVD players, cell phones, and the like has contributed to a new kind of waste called

a. techno-waste.

b. EZ-waste.

c. MSW.

d. e-waste.

Thinking Environmentally-1 Answer


The type of material that contributes most to the municipal solid waste in the United States is

a. wood.

b. food waste.

c. plastics.

d. paper.

Thinking Environmentally-2


The type of material that contributes most to the municipal solid waste in the United States is

a. wood.

b. food waste.

c. plastics.

d. paper.

Thinking Environmentally-2 Answer

© 2011 Pearson Education, Inc. CHAPTER 21 Municipal Solid Waste: Disposal and Recovery.

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