&EPA
United States Solid Waste EPA/530-S-92-019
Environmental Protection and Emergency Response July 1992
Agency (OS-305)
Characterization of
Municipal Solid Waste
in the United States:
1992 Update
Executive Summary
Recycled/Recyclable
Printed with Soy/Canola Ink on paper that
contains at least 50% post-consumer recycled fiber
-------
Ordering Information
The complete report, Characterization of Municipal Solid Waste in the United
States: 1992 Update, is available through the National Technical Information Service
(NTIS). To order, call NTIS at (703) 487-4650. A Fact Sheet highlighting the major
findings of the report is also available. To obtain additional copies of this Executive
Summary (EPA/530-S-92-019), or the Fact Sheet (EPA/530-F-92-019) at no charge,
call the RCRA/Superfund Hotline at (800) 424-9346; TDD (800) 553-7672 for the
hearing impaired. In the Washington, D.C. metro area, the number is (703) 920-9810;
TDD (703) 486-3323. !
-------
CHARACTERIZATION OF
MUNICIPAL SOLID WASTE
IN THE UNITED STATES
1992 UPDATE
Executive Summary
July 1992
Prepared for
U.S. Environmental Protection Agency
Municipal and Industrial Solid Waste Division
Office of Solid Waste
-------
-------
CHARACTERIZATION OF MUNICIPAL SOLID WASTE
IN THE UNITED STATES: 1992 UPDATE
Executive Summary
Many areas of the United States currently face serious problems in
safely and effectively managing the garbage they generate. As a nation, we are
generating more trash than ever before. At the same time, we are finding that
there are limits to traditional trash management practices. As the generation
of municipal solid waste (MSW) continues to increase, the capacity to handle
it is decreasing. Many landfills and combustors have closed, and new disposal
facilities are often difficult to site.
As a result of these problems, many communities face hard choices
when weighing trash management options. Some communities end up
paying premium prices to transport their garbage long distances to available
facilities. Others try to site facilities nearby and encounter intense public
conflict. Of course, not all communities face such problems; numerous
communities have found creative solutions through source reduction and
recycling programs, and have been able to work with the public to site new,
environmentally acceptable disposal capacity. Still, for much of the nation,
the generation and management of garbage present problems that require our
focused attention.
Identifying the components of the waste stream is an important step
toward addressing the problems associated with the generation and
management of garbage. MSW characterizations, which analyze the quantity
and composition of the municipal solid waste stream, involve estimating
how much MSW is generated, recycled, combusted, and disposed of in
landfills. By determining the makeup of the waste stream, waste
characterizations also provide valuable data for setting waste management
goals, tracking progress toward those goals, and supporting planning at the
national, state, and local levels. For example, waste characterizations can be
used to highlight opportunities for source reduction and recycling and
provide information on any special management issues that should be
considered.
Features of This Report
This report is the most recent in a series of reports released by the U.S.
Environmental Protection Agency (EPA) to characterize MSW in the United
States. It characterizes the national waste stream based on data through 1990
and includes:
ES-l
-------
• Information on MSW generation from 1960 to 1990.
• Information on MSW management—recovery for recycling and
composting, combustion,! and landfilling—from 1960 to 1990.
• Information characterizing MSW by volume as well as by weight.
• Projections for MSW generation to the year 2000.
• Projections for MSW combustion through 2000.
• Projections (presented in three recovery scenarios) for materials
recovery for recycling and composting through 2000.
Recent rapid changes in materials recycling and composting make it
difficult to predict the future of municipal solid waste management. By
presenting three possible scenario^ for recovery in 1995 and 2000, this report
illustrates how various recovery rktes (e.g., 25 percent recovery in 1995) could
be achieved. States and local communities can set their own goals and
recovery scenarios depending upon their local situations.
Readers should note that this report characterizes the municipal solid
waste stream of the nation as a w^ole. The information presented here may
not, therefore, correlate with individual state or local estimates of waste
generation and management because of local variations in MSW generation
or because state or local estimates may include wastes other than MSW.
DEFINITIONS
i
Municipal solid waste includes wastes such as durable goods, nondurable goods,
containers and packaging, food scraps, yard trimmings, and miscellaneous inorganic
wastes from residential, commercial, institutional, and industrial sources. Examples of
waste from these categories include appliances, newspapers, clothing, boxes, disposable
tableware, office and classroom paper, wood pallets, and cafeteria wastes. MSW does
not include wastes from other sources, such as construction and demolition wastes,
municipal sludges, combustion ash, and industrial process wastes that might also be
disposed of in municipal waste landfills or incinerators. \
Generation refers to the amount (weight, volume, or percentage of the overall waste
stream) of materials and products as they enter the waste stream and before materials
recovery, composting, or combustion takes place. i
Recovery refers to materials removed from the waste stream for the purpose of recycling
and/or composting. Recovery does not automatically equal recycling and composting,
however. For example, if markets for recovered materials are not available, the
materials that were separated from the waste stream for recycling may simply be
stored or, in-some cases, sent to a landfill or combustor. ,
Discards include the municipal solid waste remaining after recovery for recycling and
composting. These discards are usually combusted or disposed of in landfills, although
some MSW is littered, stored, oridisposed of on site, particularly in rural areas.
ES-2
-------
Methodology
There are two primary methods for conducting a waste characterization
study. The first is a source-specific approach in which the individual
components of the waste stream are sampled sorted, and weighed. Although
this method is useful for defining a local waste stream, extrapolating from a
limited number of studies can produce a skewed or misleading picture if used
for a nationwide characterization of waste. Any errors in the sample or
atypical circumstances encountered during sampling would be greatly
magnified when expanded to represent the nation's entire waste stream.
The second method, used in this report to estimate the waste stream on
a nationwide basis, is called the "material flows methodology." EPA's Office of
Solid Waste and its predecessors in the Public Health Service sponsored work
in the 1960s and early 1970s to develop the material flows methodology. This
methodology is based on production data (by weight) for the materials and
products in the waste stream, with adjustments for imports, exports, and
product lifetimes.
Report Highlights
This report underscores the problems we face in municipal solid waste
management: the generation of MSW continues to increase steadily, both in
overall tonnage and in pounds per capita. Nevertheless, the report indicates
that the combustion of MSW and materials recovery for recycling have
increased in recent years, while discards to landfills have decreased. Major
findings include the following:
• In 1990,195.7 million tons, or 4.3 pounds per person per day of MSW
were generated. After materials recovery for recycling and
composting, discards were 3.6 pounds per person per day. Virtually
all of these discards were combusted or sent to a landfill.
• Without additional source reduction, the amount of waste generated
in 1995 is expected to reach 208 million tons. By 2000, generation is
projected to reach 222 million tons, or 4.5 pounds per person per day.
The per capita figure for the year 2000 is a 5 percent increase over
1990 levels.
• Scenarios of 20 percent, 25 percent, and 30 percent recovery were
used for 1995. Based on current trends, projected recovery will fall
within this range.
• Recovery of MSW materials for recycling and composting was 17
percent in 1990. Combustion was 16 percent of total generation, and
ES-3
-------
the remaining 67 percent of the municipal solid waste stream was
sent to landfills or otherwise disposed.
!
• MSW was also characterized by volume. The results indicate which
materials in MSW occupy the greatest proportion of volume in
landfills, and compare these percentages to those by weight. For
example, paper and paperboard products make up 32 percent of the
discards (after recovery) by weight and 32 percent by volume; plastics
account for 10 percent by weight and 21 percent by volume; and yard
trimmings make up 19 percent by weight and 10 percent by volume.
• For the first time in this series of reports, estimates^ of the fraction of
MSW generated by residential and commercial sources were made, ft
was estimated that 55 to 65 percent of MSW comes from residential
sources, and that 35 to 45 percent comes from commercial sources.
i
Municipal Solid Waste in 1990 i
In 1990, generation of municipal solid waste totaled 195.7 million tons.
Figure ES-1 provides a breakdown by weight of the materials generated in
MSW in 1990. It shows that paper and paperboard products are the largest
component of municipal solid waste by weight (37 percent of generation) and
yard trimmings are the second largest component (roughly 18 percent of
generation). Five of the remaining materials in MSW—glass, metals, plastics,
wood and food wastes—range between 6 and 9 percent each by weight of total
MSW generated. Other materials in MSW include rubber, leather, textiles,
and small amounts of miscellaneous wastes, which each made up less than 4
percent of MSW in 1990. j
16.2 million tona
Figure ES-1. Material* generated in MSW by weight, 1990
(Total weight = 195.7 million tons)
; Glass 6.7%
13.2 million tons
Metals : 8.3%
Paper * Paperboard 37.5%y
73.3 million tons
Plastics 8.3%
116.2 million tons
Wood 6.3%
12.3 million tons
I
Food 6.7%
13.2 million tons
Yard Trimmings 17.9%^*ajsafia^-~bther 8.3% .
35.0 million tons 16.3 million tons !
ES-4
-------
Figure ES-2. Management of MSW in U.S., 1990
(Total weight = 195.7 million tons)
Landfill, other, 66.6%
130.4 million tons
Recovery, 17.1%
33.4 million tons
Combustion, 16.3%
31.9 million tons
The breakdown of how much waste went to recycling, combustion, and
landfills is shown in Figure ES-2. Recovery of materials for recycling and
composting was an estimated 17 percent in 1990. That amount varied
significantly according to the type of waste (Table ES-1). For example, over 28
percent of paper generation was recovered in 1990, while about 2 percent of
plastics in MSW were recovered.
The broad categories of materials in MSW are made up of many
individual products. The products are grouped into major product categories
as shown in Figure ES-3. In 1990, containers and packaging were the largest
Figure ES-3. Products generated in MSW by weight, 1990
(Total weight * 195.7 million tons)
Nondurables 26.7%
52.3 million tons
Durables 14.3%
27.9 million tons
Containers & Packaging 32.9%
64.4 million tons
Food, Other 8.2%
16.1 million tons
Yard Trimmings 17.9%
35.0 million tons
ES-5
-------
Table ES-1
GENERATION OF MSW, RECOVERY OF MATERIALS
AND COMPOSTING OF YARD TRIMMINGS, 1990
'
Paper and Paperboard
Glass
Metals
Ferrous
Aluminum '.
Other Nonferrous '
Total Metals ',
Plastics ;
Rubber and Leather ;
Textiles
Wood :
Other
Total Materials in Products ]
Other Wastes
Food Wastes
Yard Trimmings
Miscellaneous Inorganic Wastes
Total Other Wastes
TOTAL MSW [
Weight
Generated
(in Millions
of Tons)
73.3
13.2
12.3
2.7
1.2
16.2
16.2
4.6
5.6
12.3
3.2
144.6
13.2
35.0
2.9
51.1
195.7
Weight
Recovered
(in Millions
of Tons)
20.9
2.6
1.9
1.0
0.8
3.7
0.4
0.2
0.2
0.4
0.8
29.2
Neg.
4.2
Neg.
4.2
33.4
Percent of
Generation
of Each
Material
28.6%
19.9%
15.4%
38.1%
67.7%
23.0%
2.2%
4.4%
4.3%
3.2%
23.8%
20.2%
Neg.
12.0%
Neg.
8.2%
17.1%
Neg. = Negligible (less than 0.05 percent or 50,000 tons).
i
single product category generated in MSW by weight, at roughly 33 percent of
the total. Nondurable goods (such as newspapers and disposable food service
items) were the second largest category, at 27 percent of the total. Yard
trirnmings were approximately 18'percent and durable goods (such as
furniture and tires) were 14 percent of total generation in 1990.
ES-6
-------
MSW Volume Estimates
Although solid waste is usually characterized by weight, information
about volume is important for such issues as determining how quickly
landfill capacity is being filled and identifying the rate at which the volumes
of various materials in the waste stream are changing.
Volume estimates of solid waste, however, are far more difficult to
make than weight estimates. A pound of paper is a pound of paper whether it
is in flat sheets, crumpled into a wad, or compacted into a bale, but the
volume occupied in each case will be very different. The estimates presented
here represent the relative volume of materials as they would typically be
found if compacted individually in a landfill (a significant amount of
compaction occurs in a landfill). These estimates are based largely on
empirical data that are then used to estimate density factors (pounds per cubic
yard) for components of solid waste under simulated landfill conditions, with
corroboration from actual landfill studies. It should be noted, however, that
individual component density measurements serve only to compare
component volume requirements, one to another. The component
measurements should not be used to estimate landfill densities of mixed
municipal solid waste.
Figure ES-4 shows the materials in MSW by volume as a percent of
total MSW discards (after recovery) in 1990. The paper and paperboard
category ranks first in volume of MSW discarded (32 percent). Plastics rank
second in volume, at 21 percent of the total, and yard trimmings are third, at
10 percent. Paper and plastics combined account for over one-half of the
volume of MSW discarded in 1990.
Figure ES-4. Landfill volume of materials in MSW, 1990
(In percent of total)
Yard Trimmings 10%
Metals 11%
Plastics 21%
Rubber & Leather 6%
Textiles 6%
Wood 7%
Glass 2%
Others 5%
ES-7
-------
Table ES-2
VOLUME OF MATERIALS DISCARDED IN MSW, 1990
Paper and Paperboard
Plastics
Yard Trimmings
Ferrous Metals
Rubber and Leather
Textiles
Wood
Food Wastes
Other
Aluminum
Glass
TOTALS
1990 ,
Discards
(mil tons)
52.4
15.9:
30.8'
10.4;
4.4:
i
5.3;
11.9
13.2;
5.7'
1.6,
10.6
162.3
1
Weight
(%ofMSW
total)
32.3%
9.8%
19.0%
6.4%
2.7%
3.3%
7.3%
8.1%
3.5%
1.0%
6.5%
100%
Volume
(%o£MSW
total)
31.9%
21.1%
9.8%
8.9%
6.1%
6.4%
6.8%
3.2%
1.4%
2.2%
2.2%
100%
Ratio
(volume %/
weight %)
1.0
2.2
0.5
1.4
2.2
1.9
0.9
0.4
0.4
2.1
0.3
1.0
Table ES-2 compares 1990 volume and weight estimates for materials
in MSW contained in the report. The right-hand column shows the ratio of
volume to weight for each material. A ratio of 1.0 means that the material
occupies the same proportion by volume as by weight. Values greater than 1.0
mean that the material occupies a larger proportion of volume than weight.
Four materials stand out as having ratios of approximately 2.0 or
greater: plastics, rubber and leather, textiles, and aluminum. By contrast, yard
trimmings, food, and glass each have ratios of 0.5 or less, indicating that these
materials are quite dense and occupy proportionately less volume in landfills.
Figure ES-5 shows the product categories that make up MSW by
volume of total discards in 1990. Containers and packaging (at about 33
percent) and nondurables (at about 30 percent) occupy similar shares of MSW
by volume. Durables goods are an estimated 23 percent of MSW discards
volume.
ES-8
-------
Figure ES-S. Landfill volume of MSW product categories, 1990
(In percent of total)
Trends in MSW Generation, Recovery, and Discards
Generation of municipal solid waste grew steadily between 1960 and
1990, from 88 million to over 195 million tons per year. Per capita generation
of MSW increased from 2.7 pounds per person per day in 1960 to 4.3 pounds
per person per day in 1990. By 2000, projected per capita MSW generation is
4.5 pounds per person per day (222 million tons). This projection suggests a
substantial slowing in the rate of increase of MSW generation. Actually
achieving the projected decline hinges on diverse variables that are difficult
to predict. They range from demographic changes, economic factors, and
consumer preferences such as those for lighter packaging materials, to social
trends such as the decline in newspaper readership, as well as efforts in source
reduction such as backyard composting, packaging reduction, and production
of more durable products.
Recovery has increased gradually from about 7 percent of MSW
generated in 1960 to 17 percent in 1990. Projected scenarios for recovery are
between 20 and 30 percent in 1995 and 25 and 35 percent in 2000. To achieve
these recovery rates, some products will have to be recovered at rates of 50
percent or more, and there will have to be substantial composting of yard
trimmings.
Combustors handled an estimated 30 percent of MSW generated in
I960, most of them with no energy recovery and no air pollution controls. In
the 1960s and 1970s, combustion dropped steadily as the old incinerators were
closed, reaching a low of less than 10 percent of MSW generated by 1980. More
recently, combustion of MSW has been increasing again (to 32 million tons,
or roughly 16 percent of generatidn, in 1990). All major new facilities have
energy recovery and are designed to meet air pollution standards.
ES-9
-------
The report projects that about 35 million tons of MSW will be
combusted in 1995, and 46 million tons will be combusted in 2000. Estimates
of combustion projections are based on an assumption that the facilities will
operate at 80 percent of capacity:.
Landfill use fluctuates with changes in the use of alternative solid
waste management methods. For example, when the use of combustion for
MSW management declined and recovery rates were low, the MSW
percentage sent to landfills increased (Figure ES-6). Alternatively, when
recovery and combustion of MSW increased, the percentage of MSW
discarded to landfills declined. In 1960, approximately 62 percent of MSW was
sent to landfills. This increased to 81 percent in 1980, then decreased to 67
percent in 1990 due to changing trends in municipal solid waste
management.
Recovery for recycling at! the 25 percent scenario for 1995 and the 30
percent scenario for 2000 will keep total national discards of MSW after
recovery at about the current leivel of 162 million tons or less, considering
projected rates of generation. Cpmposting and combustion are required to
substantially decrease the amoxints landfilled (Figure ES-6).
As we approach the twenty-first century, integrated waste management
with a focus on source reduction and recycling is clearly the solution to our
growing waste management needs. Through source reduction, recycling, and
composting, we can reduce generation and increase recovery, and, in turn,
reduce the quantities of waste that must be managed by combustors and
landfills.
Million tons
240
Figure ES-6. Municipal solid waste management, 1960 to 2000
I
Yard Trimmings
1995
2000
ES-10
U.S. GOVERNMENT PRINTING OFFICE : 1992 O - 327-943 QL 3
-------
-------
vvEPA
United States
Environmental Protection Agency
(OS-305)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
EPA/530-S-92-019
July 1992
------- |