Environmental Sciences: Towards a
Sustainable Future Chapter 18
Municipal Solid Waste: Disposal
and Recovery
Chapter Introduction
Danehy Park- Cambridge, MA
Danehy Park
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50-acre park opened in 1990.
Built on a former city dump.
Light system in the restrooms to warn of
evacuation in the case of methane buildup.
Many dumps since the “solid-waste crisis”
of 1970s and 80s have been converted to
parks, golf courses, and nature preserves.
The Solid-Waste Problem
Lesson 18.1
MSW
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MSW=Municipal Solid Wastes
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The total of all materials from homes
or commercial establishments thrown
away and collected by local
governments.
Commonly called trash, refuse, or
garbage.
Factors Contributing to Increasing Amounts
of MSW
Factors Contributing to Increasing
Amounts of MSW
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In part by: Increasing populations
More so by: Changing lifestyles,
increased use of disposable
materials*, excessive packaging*
* = two largest contributors to waste volume
Compare the numbers:
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1960 the nation generated 2.7 pounds
of MSW per person per day.
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2003 the nation generated 4.5 pounds
per person per day.
MSW Patterns of Disposal
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US 1998: 55% disposed in landfills, 28%
recovered for recycling and composting,
17% combusted.
US 2003: 55.4% landfills, 30.6% recycling,
14% combustion.
Over the past 10 years, the overall trend is
landfill and combustion declining, recycling
increasing.
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Pattern not the same for highly populated areas like
Japan (combusts 75%) and Western Europe (0ver
50%).
US: MSW Components
The US Fate of MSW
Landfills: waste put on or in the ground
and covered with earth.
 Problems with old
landfill structures.
 Leachate generation
 Methane production
 Incomplete
decomposition
 Settling
Leachate Generation
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As water percolates through the refuse
and ground, it carries contaminates
with it to ground water.
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Florida: Superfund helped to get
landfills state-of-the-art liners to
prevent ground water contamination
Much of the land is flat, only a few feet
above sea level and rests on watersaturated limestone…big problem.
Methane Production
Natural Decomposition.
 Buried wastes are anaerobicaly
broken down by detritus feeders
creating biogas.
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Gases seeping to the surface kill
vegetation, leading to erosion that
exposes the unsightly wastes.
Biogas Exploitation
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390 commercial landfill gas
facilities in the US
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California has the largest facility
1998: produced 108 trillion BTU’s
of energy=20 million barrels of oil.
2005: produced 9 billion kWh of
electricity.
Riverview, Michigan
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The city collaborates with DTE to
“mine” the landfill gas under the 212acre landfill (Mt. Trashmore).
Provides 3700 homes with energy.
Doubles as a ski and recreation area
during winter months.
Incomplete decomposition
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Materials don’t completely
break down.
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Paper makes up 35% of the
MSW. If paper is recycled, it
won’t become MSW.
 30
year old papers have been
recovered (readable).
Settling
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Building not built on landfills
because of settling.
Causes a problem for playgrounds,
golf courses that are converted
landfills because it creates shallow
depressions (or even deep holes)
that hold water and seeps into
ground water.
EPA: Improving Landfills
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Upgraded siting and construction
regulations.
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Sited on high ground.
Floor contoured.
Layering of materials, leachate
draining system, and liners.
Ground water monitoring.
Siting: Public Reactions
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LULU (locally
unwanted
landuse)
NIMBY (not in
my backyard)
NIMTOO (not in
my term of
office)
Siting Problems
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Drives up the cost of waste disposal.
Leads to inefficient and equally
objectionable practice of long-distance
transfer. Table 18-1 p 470.
Advantages of Combustion: waste to energy
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Can reduce weight by 70% and volume by
90%.
Toxic/hazardous materials concentrated into
two streams for easier handling and control.
Generate electricity.
No changes needed for collection procedures.
2/3 of combustion facilities are WTE facilities
(compliant with clean air act regulations).
Resource recovery.
Combustion: Drawbacks
 Health affects: older, poorer managed
facilities.
 Expensive to build.
 Ash loaded with heavy metals.
 Must have continuing supply of MSW.
 Impedes recycling (direct competition
for same materials).
Waste to Energy facility (Figure 18-7 page 471)
Steps to process p.471, #ed.
Cost of MSW disposal
Tipping fees: $30-$100 per ton.
 Transportation costs.
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Increasing expense has lead to
illegal dumping.
Solutions
Lesson 18.2
The Solutions
Reduction
 Recycling
 Composting
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Source Reduction
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Definition: practice of designing,
manufacturing, purchasing, or using
materials in ways that reduce the amount
or toxicity of the trash collected.
Waste prevention
Accomplishes two goals:
 Reduces amount of waste to be
managed.
 Conserves resources.
Source Reduction in Action
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Lightening the weight of many items
has reduced the amount of materials
used.
Electronic communication lessens
paper load.
Durable goods made reusable.
Lengthening product life.
Get off the bulk mail list
Recycling as a Solution
More than 75% MSW is recyclable.
 Primary recycling: original waste
material made back into same
product. News papers to newsprint
 Secondary recycling: waste made
into a new product. Newspaper to
cardboard
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Recyclable Materials
Paper and
paperboard
 Most glass
 Some forms
of plastics
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Metals
 Yard wastes
 Textiles
 Old tires
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The Most Successful Recycling Programs
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No cost to recycle but PAYT for MSW
Mandates
Make it curbside
Goals are ambitious but clear and
feasible
Efforts made to involve industry
Municipality has hired a recycling
coordinator
“Experience has shown that at
least two-thirds of
households will recycle if
presented with a curbside
pickup program”
Fact:
 A one
meter stack
of newspapers is
equal to the
amount of pulp
from one tree.
Plastic Recycling
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Code 2: HDPE-high density polyethylene.
Code 1: PETE-polyethylene terephthalate.
Use for recycled plastics is limited
somewhat because of contamination in the
cross over process. Ex: some may not be
reused for food containers.
Composting
 Currently 13% of MSW, becoming
more popular as it is banned from
MSW collections.
 End product is a residue of humuslike
material.
 3800 municipal yard waste
composting programs reported in
1998
MRF’s- “murfs”
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2001 there were 480 operating in the
US.
Wastes are sorted and shipped to
proper locations for reuse.
Public Policy and Waste Management
Lesson 18.3
MSW Regulations
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Solid waste disposal act 1965
Resource recovery act 1970 and1976
Superfund act 1980
Hazardous and solid waste
amendments 1984
Integrated Waste Management
Different combinations of source
reduction, WTE combustion,
recycling, recovery facilities,
landfills, and composting
depending on the options that work
best for the region.
 A system of several alternatives in
operation at the same time.
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Reduce, Reuse, Recycle
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Recycling is the wave of the future.
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Should not be the main pursuant in
lieu of reduction or reuse
Reduction is the most
environmental sound.
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Wastes that are not generated do not
need to be managed.
Sustainable MSW Management
Waste reduction
 Safe waste disposal
 Recycling and reuse
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