Towards Sustainable Waste Management Using a
Life-cycle Management Decision Support Tool
Keith A. Weitz
Subba R. Nishtala
Research Triangle Institute
3040 Cornwallis Road
Research Triangle Park, NC 27709
Susan A. Thorticloe
*U.S. Environmental Protection Agency/Office of Research and Development
Air Pollution Prevention and Control Division (MD-63)
Research Triangle Park, NC 2771 1
Abstract
I^ocal governments have the primary responsibility for the collection, treatment, and disposal of
municipal solid waste. In developing sustainable strategics for solid waste management,
communities seek approaches that are economically viable and beneficial to the environment and
quality of life. Although communities have had access to reliable cost information related to their
MSW management systems, they have lacked comparable environmental information with which
to assess the environmental benefits and burdens of alternative MSW management options. Many
communities, planners, and policy-makers are often faced with limited and unorganized
information on which to base decisions regarding integrated MSW management strategies. A
computer-based decision support tool has been developed through a partnership of the U.S.
Environmental Protection Agency and the Research Triangle Institute and its research partners.
The tool has been designed to assist local governments in evaluating the cost and environmental
performance of integrated MSW management systems. Ongoing case studies of the tool at the
local level are summarized. The tool is also being evaluated for application at state and national
levels through case studies. One state-level case study is summarized to illustrate how the
decision support tool was used to estimate the environmental benefits of the state's recycling
program over time.
Introduction
Local governments have the primary responsibility for the collection, treatment, and disposal of
municipal solid waste (MSW). Efficient use of manpower, equipment, materials, and energy is one
of the keys to building a sustainable MSW management system. Another key is making the system
economically feasible over the long term.
In developing sustainable strategics for MSW management, communities seek approaches that are
economically viable and beneficial to the environment and quality of life. Although communities
have had access to reliable cost information related to their MSW management systems, they have
lacked comparable environmental information with which to assess the environmental benefits and
/•' burdens of alternative MSW management options. Many communities and solid waste planners
are often faced with limited and unorganized information on which to base decisions regarding
integrated MSW management strategics.
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The U.S. Environmental Protection Agency's (U.S. EPA's) Office of Research and Development
is working with the Research Triangle Institute (RTI) and its partners to develop a computer-
based decision support tool designed to evaluate the cost and environmental performance of
integrated MSW management systems. By adopting MSW management strategies that improve
the integration and efficiency of MSW management operations, local governments can help
reduce the release of greenhouse gases, conserve energy and other natural resources, reduce
impacts to local air and water quality or ecosystems, and improve the quality of life in their
communities.
In addition to the decision support tool, this research is producing a stand-alone database that
enables users to search for data specific to a waste management system unit operation, structure,
piece of equipment, or life-cycle inventory (LCI) parameter (air emission, waterborne effluent,
solid waste). The information and tools developed through this effort will enable the evaluation of
the tradeoffs among environmental burdens, energy, and costs for different integrated waste
strategies for MSW management including collection, separation, transportation, material
recovery facilities, remanufacturing, composting, combustion, and landfilling.
Decision Support Tool
The decision support tool is a screening-level tool designed to aid in evaluating the cost and
environmental burdens of integrated MSW management strategies. It enables users to simulate
existing MSW management strategies and conduct scenario analyses of new strategies to optimize
the cost or environmental performance of the system. The tool is designed to be used in
conjunction with community-specific data such as waste generation and composition, recycling or
diversion programs, and facility (e.g., landfill) design and operation.
The processes that can be modeled using the tool include multiple alternatives for waste
collection, transfer stations, materials recovery facilities, mixed municipal and yard waste
composting, combustion, refuse-derived fuel combustion, and disposal in a traditional, bioreactor,
or ash landfill. Existing facilities and equipment can be incorporated as constraints to ensure that
previous capital expenditures are not negated. A screen capture of summary-level results from the
tool is shown in Figure I.
In addition to viewing summary-level results, users can click down to obtain more detail about
each waste management operation selected. Data on all environmental burdens that include multi-
pollutants and media are available on a total or process level basis. This information can be used
to help evaluate the tradeoffs of different strategies and evaluate environmental performance. In
addition, the full costs associated with the management of integrated waste management systems
are also provided for the total strategy or on a process level basis.
Communities and solid waste planners can use the tool, for example, to evaluate the effects of
changes in the existing MSW management on cost; identify least-cost ways to manage recycling
and waste diversion; and evaluate options for reducing greenhouse gases, criteria pollutants, and
environmental burdens to water quality or ecosystems. The tool will also be valuable to other
user groups, including military bases, environmental and solid waste consultants, industry, life-
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cycle practitioners, and environmental advocacy organizations in responding to the following
example issues:
• changes in waste diversion, or recycling goals,
• changes in market value for recovered materials,
• quantifying potential environmental benefits associated with recycling, and
• identifying strategies for optimizing energy recovery from MSW.
Through ongoing case studies, the potential applications of the tool will he evaluated to help
clearly understand the potential uses and limitations of the tool and information. The decision
support tool contains general engineering cost parameters, and therefore is not intended for
setting prices for any specific waste management service. The cost results provided by the tool
represent screening-level engineering costs that accrue to the public entity (i.e., local
government). A more detailed cash flow analysis substituting local parameters would be needed to
determine the appropriate prices for services and materials. The tool is also not designed to
conduct iife-cycic comparisons of any specific products or materials. It is considered to be a
comprehensive tool of significant value in finding improved solutions for sustainable waste
management.
Testing of the Tool in Community-Based Case Studies
A prototype of the decision support tool is being tested in a number of case study applications.
Case studies are ongoing with Lucas County, Ohio; the Great River Regional Waste Authority,
Iowa; Anderson County, South Carolina; the State of Wisconsin; the Integrated Waste Services
Association; and the U.S. Navy. Although the tool was originally designed with local
communities in mind, we are testing it in applications at the state and national levels as well.
Examples of the types of issues being analyzed with the decision support tool for different groups
and studies are:
¦ Lucas County, Ohio, is currently developing a 15-year plan for their solid waste
management system. They feel their current waste operations are not cost effective and
ignore pollution and life-cycle implications. The analyses and results of this case study are
helping in the development of integrated, cost-effective, and environmentally preferable
plans and targeting opportunities for increasing recycling rates, reducing costs, and
improving environmental performance.
¦ The Great River Regional Waste Authority in Iowa is exploring the efficiency of
integrated collection system versus multiple collection options. Their goal is to evaluate
effects of reconfiguring service areas and applying existing systems to them, and to
develop a waste management plan for a 50% recycling scenario that is to be presented to
the state authority.
¦ Anderson County, South Carolina, is evaluating the cost and environmental implications
of implementing a residential curbside recycling program for the more densely populated
areas of the County as well as setting up a yard waste composting program. The results of
this study will assist the County in determining the most cost-effective strategies for
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implementing the programs while simultaneously considering environmental performance.
The State of Georgia used the tool to analyze the effects of a yard waste ban on air
emissions for Gwinnett County, Current nitrogen oxide (NO*) emissions attributable to
yard waste collection were estimated to be 105 tons per year, and the elimination of a yard
waste ban would result in an 11% decrease in NO*. The number of trucks needed for
collecting commingled yard waste with MSW increases from 171 (with no yard waste
collected with MSW) to 201. Discussions are underway to conduct additional case
studies in Georgia in evaluating regional solutions to integrated waste management.
¦ The State of Wisconsin is investigating the environmental benefits of statewide recycling
programs. Wc are using the tool to analyze how changes in levels of state-mandated
recycling goals can potentially affect environmental burdens. The results of this study will
assist the State in deciding what solid waste strategics should be used in the future to meet
environmental improvement goals.
¦ The Integrated Waste Services Association is interested in analyzing the effect that
advancements in MSW management technologies have on greenhouse gas emissions. We
are using the tool to investigate the greenhouse gas emissions from various technologies
including landfill gas recovery, waste-to-energy combustion, and recycling.
¦ The U.S Navy has requested a case study for the Navy Region Northwest. There is major
interest to reduce cost, increase recycling rates, and ensure that environmental goals are
being met. In addition, with the closing of smaller local landfills and transporting waste by
rail to a larger regional site, the Navy is interested in evaluating the change in
environmental burdens, energy, and economics. The Navy is also evaluating options that
would combine waste from nearby communities to identify more cost effective and
environmentally preferable solutions to a more regional approach for integrated waste
management. The case study is to be conducted by the fall of 2000 and will result in
implementation of a solid waste management plan. The Navy is also considering additional
case studies in San Diego and the Pacific Rim.
These case studies are providing cost and environmental information about alternative waste
management strategies to these groups to assist in the development of management plans and
policies. The case studies also are enabling the research team refine the methods and data used in
the decision support tool as well as the user interface to the tool. For illustrative purposes, the
details for one of these studies (State of Wisconsin) appear in the following section. However,
the findings are considered preliminary, not final. Once comments arc received from the State of
Wisconsin, and the tool and associated data have received final clearance, we will then be able to
release findings from U.S. case studies.
Additional case studies are planned and will reflect the issues of urban and rural settings
throughout the United States to ensure that the decision support system is flexible enough to
handle the wide range of variation among local communities.
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Wisconsin Case Study Methodology and Results
The purpose of the State of Wisconsin case study was to use the decision support tool to estimate
the environmental effects of recycling and waste management in Wisconsin. In this study, the full
life-cycle benefits (or burdens) of additional recycling being done in Wisconsin in 2000 as
compared to 1995 were quantified. A Life-cycle approach was taken to estimate the air, water,
and solid waste releases, and the energy consumed for managing Wisconsin's waste in 1995 and
2000. This approach includes the stages of waste collection, processing, treatment, and disposal
and materials recycling and reprocessing. This section presents a summary of the methods,
results, and findings of the case study for purposes of illustration.
Waste Composition, Generation, and Recycling Data
A case study methodology document was prepared that describes the data sources and
assumptions made in entering the waste composition, generation, and recycling data for the State
of Wisconsin for the mode! years 1995 and 2000. Waste generation and recycling rates, as shown
in Tabic 1, were estimated for the years 2000 and 1995 based on information collected in the
state.
Collection, Recycling, and Disposal Options for Residential, Multifamily, and
Commercial Waste
In establishing a model scenario for year 2000 and year 1995 for the entire State of Wisconsin, a
general strategy of waste management was defined. This strategy was used as the basis for
calculating results and includes:
• Collection of presorted recyclables and remaining (residual) mixed waste.
• Processing of recyclables in a presorted materials recovery facility.
• Disposal of residual waste in a Subtitle D landfill.
• Composting of yardwaste in a yardwaste composting facility (note that, in addition
to yardwaste sent to the compost facility, yardwaste is also composted in
residential backyards).
Key Assumptions Employed
When applying the decision support tool to the real-world waste management practices of
Wisconsin, some assumptions are required to "fit" the real-world practices into the modeling
environment of the tool. For example, a community may track a waste material that is not
included in the tool (e.g., pallets, household hazardous waste) and thus an assumption must be
made as how best to handle such material.
Some of the key assumptions employed in the Wisconsin case study include:
• Some materials that were recycled in Wisconsin could not be treated as such in the
tool because it does not contain remanufacturing data for those items (e.g., food
waste, batteries, tires). These items were excluded from the waste generation
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numbers for purposes of the case study and represent approximately 5% of waste
generated. This assumption decreases the total amount of material recycled, and
ignores the downstream LCI benefits (or costs) of recycling the materials. The
materials that were excluded from the analysis arc listed in Table 2.
• The LCI for composting of 290,000 tons of yardwaste composted in residential
backyards was added to the LCI of yardwaste that was collected and treated at a
composting facility for each model year.
Discussion of Results
The results from the analysis of recycling in Wisconsin in 1995 versus 2000 are presented in Table
3. From these results, the following points were made:
• The recycling levels for model year 2000 were higher than those for model year
1995, for all waste components. The net emissions include emissions from the
collection, processing, treatment, disposal, and remanufacturing of waste and
recyclables in Wisconsin.
• For several air emission parameters and for energy consumption, the net numbers
are negative. The negative number indicates that there was a net savings or offset
in emissions for those LCI parameters due to the environmental benefits of
recycling.
• The results show that recycling at year 2000 levels results in lower LCI parameter
values for some parameters, and higher values for others.
• The higher net values of LCI parameters in 2000 can be explained by the
increased quantities of waste generated, collected, recycled, and disposed of in
2000 over 1995 levels. For example, in year 2000, there was a 4% increase in the
quantity of waste land filled over 1995 levels. There was a corresponding 11%
increase in net methane releases for year 2000. This increase in methane
emissions can be partly explained by the higher quantity of waste landfilled (that
generates methane during decomposition) in year 2000.
• For some air emissions, recycling at year 2000 levels resulted in lower emissions
compared to year 1995 (which had lower recycling levels). The lower numbers
for model year 2000 arc due to the environmental benefits of recycling.
• Emissions and energy use in the remanufacturing of recyclables recovered from
waste dominate emissions and energy use in the waste collection, processing,
treatment, and disposal stages of waste management.
Project Information
When completed, the decision support tool and LCI database will be publicly available. RTI is
working to develop an agreement to determine how the outputs will be formally released. The
EPA is planning to develop a Cooperative Research and Development Agreement (CRADA) with
the commercial partner or partners that will address future updates, maintenance, technical
support, and other issues associated with the release and application of the decision support tool
and LCI database.
Major emphasis will be towards ensuring that the cost of the tool is kept to a minimum to provide
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wide access. The fee for the release of the tools will help to cover the costs associated with future
updates, maintenance, and technical support that stakeholders have stated are essential in ensuring
the success of this tool.
Those who arc interested in application of the tool, such as local and state governments, may
want to obtain a copy for use in-house or to contract the services of consultants. The tool and
supporting documentation have been developed so that solid waste management professionals can
use the tool for a wide range of applications. A user's manual and other extensive documentation
will be available as well as documentation of the case studies conducted to dale. The details of
how the final outputs will be released will be determined over the next several months with
emphasis on the needs and interests of the stakeholders.
General project information and interim draft documentation are completed and being finalized.
Final reports include user's manuals for both the database and decision support tool, and a project
overview report with detailed documentation of process models, data, and methodology. Final
reports and documentation are scheduled to be released this summer. Available information can
be found on the project Internet site (www.rti.org/units/ese/p2/lca.cfm#life), including a
PowerPoint presentation of the decision support tool. The research team is also preparing a series
of peer-reviewed journal articles to highlight the different aspects and uses of this too! and to
summarize findings from case studies in different communities where this life-cycle tool has been
applied.
Acknowledgments
This research is being conducted by R IT, North Carolina State University, University of
Wisconsin, Franklin Associates, Ltd., and Roy F. Weston, Inc., through a cooperative agreement
with U.S. EPA's Office of Research and Development. Support was also provided from other
groups, including the Environmental Research and Education Foundation that was responsible for
funding the research for developing the life-cycle data needed for modeling modern sanitary
landfills. EPA and the research team appreciate the efforts of more than 70 stakeholders who
have provided enthusiasm, expertise, and insight in ensuring that the outputs from this research
will address their needs and lead to sustainable waste management.
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Table 1. Summary of Waste Flows Modeled for tiie State of Wisconsin.
Change in 2000
Waste Generation by Category
2000
1995
from 1995
(projected)
levels (%)
(data used to generate results)
(tons)
(tons)
Waste Generated
Residential
1,880,000
1,860,000
1
Multifamily
220,000
213,000
3
Commercial
1,600,000
1,440,000
11
Materials recycled in Wisconsin that are
220,000
201,000
10
not captured in model
total
3,920,000
3,720,000
6
Materials Recycled
Residential
353,000
349,000
1
Multifamily
36,900
35,800
3
Commercial
617,000
557,000
11
Materials recycled in Wisconsin that are
220,000
201,000
10
not captured in model
total
1,230,000
1,140,000
7
Yardwaste Diverted from Landfill
Backyard Composting
290,000
290,000
0
Yardwaste Composting at Facility
200,000
199,000
1
total
490,000
489,000
0
Waste Landfilled
Residential
1,330,000
1,310,000
1
Multifamily
183,000
177,000
3
Commercial
982,000
886,000
11
total
2,490,000
2,370,000
5
Notes:
• These data are outputs from the decision support tool to generate the life-cycle profile for waste
management in Wisconsin.
• The recycled quantities are slightly different from actual numbers expected using Wisconsin data due
to rounding and the assumptions made.
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Table 2. Materials Recycled in the State of Wisconsin But Not Captured By This Model.
Materials
2000 (projected)
1995
(tons)
(tons)
foam polystyrene packaging
0
40
foam polystyrene nondurable goods
0
310
other plastic containers
9,920
8,610
other plastic packaging
300
240
food waste
14,800
13,400
vehicle batteries
41,100
36,700
tires
1,730
1,550
textiles, rubber & leather products
22,000
18,500
carpets and rugs
750
560
major appliances
69,500
69,800
miscellaneous durables
20,000
17,300
wood pallets
40,000
33,700
miscellaneous packaging
440
400
totals
221,000
201,000
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Tabic 3. Summaries of Life-Cycle Parameters for the State of Wisconsin in 2000 and 1995
Net Decreases in LCI for year 2000 over year 1995 levels
Decrease in 2000
Parameter
Units
2000 LCI
1995 LCI
(%)
Energy Consumption
Million BTU/year
-18,400,000
-16,300,000
13
Air Emissions
Total Particulate Matter
lbs/year
-7,100,000
-6,660,000
7
Nitrogen Oxides
lbs/year
-5,700,000
-4,110,000
39
Sulfur Oxides
lbs/year
-28,300,000
-26,200,000
8
Carbon Monoxide
lbs/year
-58,900,000
-53,400,000
10
Carbon Dioxide (Biomass sources)
lbs/year
4,810,000,000
-4,250,000,000
13
Hydrocarbons (non-CH4)
lbs/year
-2,180,000
-2,070,000
5
Lead
lbs/year
-172,000
-156,000
10
Ammonia
lbs/year
-3,160
-2,800
11
Total Solid Waste
lbs/year
-260,000,000
-258,000,000
1
Water Releases
COD
lbs/year
-14,000,000
-12,500,000
12
Sulfuric Acid
lbs/year
-317,000
-272,000
17
Ammonia
lbs/year
-59,000
-52,000
13
Net Increases in LCI for year 2000 over year 1995 levels
Increase in 2000
Parameter
Units
2000 LCI
1995 LCI
(%)
Air Emissions
Carbon Dioxide (Fossil sources)
lbs/year
730,000,000
633,000,000
15
Carbon Equivalents
tons /year
153,000
138,000
12
Methane (CH4)
lbs/year
18,800,000
17,900,000
5
Hydrochloric Acid
lbs/year
-31,500
-38,000
17
Water Releases
Dissolved Solids
lbs/year
4,630,000
4,450,000
4
Suspended Solids
lbs/year
-113,000
-339,000
67
BOD
lbs/year
5,740,000
5,290,000
9
Oil
lbs/year
730,000
661,000
10
Iron
lbs/year
765,000
695,000
10
Phosphate
lbs/year
17,500
16,200
8
Zinc
lbs/year
10,700
9,650
11
Note:
• These data are totals for the entire waste management system including collection, recycling,
composting, disposal, and remanufacturing.
• Negative numbers indicate that there were net savings in emissions.
1 1
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_ ,-nn TECHNICAL REPORT DATA
JN ruvi iv -• Kl P DUU a^piease rca(j instructions on the reverse before comf
1 REPORT NO 2.
EPA/600/A-01/071
3 R
4 TITLE AND SUBTITLE
Towards Sustainable Waste Management Using a
Life-cycle Management Decision Support Tool
5. REPORT DATE
6. PERFORMING ORGANIZATION CODE
7, AUTHORS
K.A. Weitz and S. R Nishtala (RTI), and
S. A. Thorneloe (EPA)
8. PERFORMING ORGANIZATION REPORT NO
9 PERFORMING ORGANIZATION NAME AND ADDRESS
Research Triangle Institute
3040 Cornwallis Road
Research Triangle Park, North Carolina 27709
10 PROGRAM ELEMENT NO.
11 CONTRACT/GRANT NO.
CR823952
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Published paper; 2/00
14. SPONSORING AGENCY CODE
EPA/600/13
15 supplementary notes ^ppcjj project officer is Susan A. Thorneloe, Mail Drop 63, 919/
541-2709. Presented at WASTECON 2000, Cincinnati, GH, 10/23-26/00.
i6 abstract paper discusses a computer-based decision support tool that has been
developed to assist local governments in evaluating the cost and environmental per-
formance of integrated municipal solid waste (MSW) management systems. Ongoing
case studies of the tool at the local level are summarized. The tool is also being
evaluated for application at state and national levels through case studies. One state-
level case study is summarized to illustrate how the decision support tool was used
to estimate the environmental benefits of the state's recycling program over time.
(NCTE: Local governments have the primary responsibility for the collection,
treatment, and disposal of MSW. In developing sustainable strategies for solid waste
management, communities seek approaches that are economically viable and bene-
ficial to the environment and quality of life. Although communities have had access
to reliable cost information related to their MSW management systems, they have
lacked comparable environmental information with which to assess the environmen-
tal benefits and burdens of alternative MSW management options. Many communities,
planners, and policy-makers are often faced with limited and unorganized informa-
tion on which to base decisions regarding integrated MSW management strategies.)
17 KEY WORDS AND DOCUMENT ANALYSIS
a DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
C. COSAT1 Field/Group
Pollution
Municipal Engineering
Wastes Performance Eval-
Management uation
Evaluation Decision Making
Cost Effectiveness
Pollution Control
Stationary Sources
13B
14G
05A 051
05 J
14A
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
21. NO. OF PAGES
11
20. SECURITY CLASS (This Page)
22. PRICE
EPA Form 2220-1 (Rev. 4-77 ) PREVIOUS EDITION IS OBSOLETE forms/admin/tedirpt.frm 7/8/99 pad
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