The U.S. EPA’s Decision Support Tool for Sustainable Solid Waste Management

Susan ThorneloeNational Risk Management Research Laboratory

Air Pollution Prevention & Control DivisionResearch Triangle Park, North Carolina

LCA and Integrated Waste ManagementPrague, Czech Republic

April 13, 2004

The U.S. EPA’s Decision Support Tool for Sustainable

Solid Waste Management

What We’ll Cover Today . . .

• Background Waste Management in

the U.S. Decision Support Tool

• Case Studies• Next steps• Summary

Solid Waste Management in the United States

• Prior to the 1970s Sanitary landfills were rare Wastes were dumped and burned to reduce volume Incinerators had no pollution control or energy recovery

• Today More integrated and complex approaches “Waste-to-energy” facilities with minimal environmental

burden “Sanitary” landfills

• Requirements for design, operation, and monitoring• Large landfills are required to collect and control landfill gas• Different approaches being evaluated including allowing leachate

recirculation and other liquid additions

050

100150200250

Million Metric Tons

1974 1980 1990 Today

U.S. Municipal Waste Management

Recycling

Combustion

Landfilling

Decision Support Tool

Purpose: To assist solid waste managers in determining optimal waste

management strategies that minimize total cost and environmental burdens

Decision Support Tool for Sustainable Solid Waste

Management • Communities requested

planning tool that Considers site-specific factors,

data, and concerns Is flexible and can consider

different needs for• Rural and urban areas• Residential and commercial waste

Considers costs and environmental tradeoffs

What is the Municipal Solid Waste Decision Support Tool?

• A computer-based tool to assist solid waste managers in determining optimal waste management strategies that minimize cost and environmental burdens.

• Components of the MSW-DST include:– Process models (MS Excel)– Mass flow model– Optimization routine (Cplex)– User interface (MS Visual Basic)

System Boundaries

MSW MANAGEMENT ACTIVITIES

kWh Gas Steam Compost Recyclables

MunicipalSolid Waste

Energy Materials

Collection

Combustion

Compost

MaterialsRecovery

Landfill

WaterReleases

Materials andEnergy Offsets

AirEmissions

SolidWaste

Waste is generated by residential, multifamily, and commercial sectors and collected and transported

for separation and recycling, combustion, composting, and/or landfilling. These activities consume

energy and materials and result in environmental burdens. Any materials or energy that are recovered

may create offsets of virgin materials in the manufacturing and energy sectors.

Life-Cycle Analysis of GHG Emissions

MSW Flow

Collection

Material Recovery Facility

Waste-to-Energy Combustor

Landfill

Refuse DerivedFuel

Compost

Remanufacturing

Transfer Station

Transfer Station

Transfer Station

Transfer Station

Transfer Station

Residue

Input site-specific data in Process models

Optimization Module

 Alternative Strategies

Requirements: - Mass - Regulations - Targets

USER

Cost & Life-Cycle Inventory Coefficients

MSW-DST Framework

Emphasis• Sound science producing results which

are credible and objective• Close interaction with all stakeholders

and rigorous review process• Providing more holistic approach

consistent with EPA’s emphasis on cleaner, cheaper, and smarter environmental management

Complex Solid Waste Decisions Being Evaluated

How do we ensure

• Cost efficient waste management?

• Meeting state mandated recycling goals?

• Continued improvement of the environment?

• Fast, objective analysis of options?

Environmental Aspects• Impact to water sheds and air

quality • Energy consumption and offsets• Benefits from materials

recycling

Economic/Social Aspects• Municipal budgets• Need for new facilities• Household convenience

Results =•Good Science•Cost Savings•Environmental Improvement•Sustainable Solutions

Identified as one of the most

important new developments in

U.S. waste management for the

21st Century

MSW DST Case Studies

• Anderson County, South Carolina

• Atlanta, Georgia• Great River Regional

Waste Authority, Iowa• Lucas County, Ohio• Madison, Wisconsin• Minneapolis, Minnesota• Portland, Oregon• Wake County, North

Carolina• Seattle, Washington

• Spokane, Washington• State of California • State of Georgia• State of Washington• State of Wisconsin (update)• Subbor – ETV GHG Center• U.S. Conference of Mayors –

U.S. GHG Study• U.S. Navy Region Northwest• Vancouver, British Columbia

Four Case Studies• St. Paul, Minnesota• State of Washington (Comparing

two urban and two rural regions)• EPA’s New Research Facility• U.S. Study on Trends in

Greenhouse Gases & Solid Waste Management

• Other Studies

St. Paul, Minnesota

• Comparison of composting of biodegradable waste versus waste-to-energy and landfilling

Comparison of Annual Cost

0

1

2

3

4

5

6

Million U.S.

Dollars

Landfilling Waste-to-Energy

Composting

Comparison of Annual Energy Usage (MBTU)

-80,000

-60,000

-40,000

-20,000

0

20,000

40,000

Landfill WTE Compost

Comparison of Annual Tons of Greenhouse Gases

-3,000

-2,500

-2,000

-1,500

-1,000

-500

0

500

1,000

1,500

2,000

Landfill WTE Compost

Carbon

Equivalents

State of Washington• Goal was to

compare residential curbside collection and recycling to landfilling and Waste-to-Energy for two urban and two rural regions

Comparison of Annual Cost for Urban-West

40

42

44

46

48

50

52

Million U.S.

Dollars

Urban-WestRecycling

Urban-WestLandfilling

Comparison of Energy Conserved versus Energy Used for Recycling

0

5

10

15

20

25

30

35

40

45

Urban West Urban East Rural West Rural East

Mon

thly

kW

h pe

r Hou

seho

ld

RecyclingEnergy Used

UpstreamEnergyConserved

Urban West Region – Annual Energy Use (MBTU)

-3,000,000

-2,500,000

-2,000,000

-1,500,000

-1,000,000

-500,000

0

500,000

UW - Recycling UW - Landfill

Urban West Region – SOx Emissions (kg/yr)

-2,000,000-1,800,000-1,600,000-1,400,000-1,200,000-1,000,000

-800,000-600,000-400,000-200,000

0200,000

UW - Recycling UW - Landfill

Urban East Region - Annual Cost

10,000,000

10,500,000

11,000,000

11,500,000

12,000,000

12,500,000

UE - Recycling UE - WTE

Urban East Region – Annual Energy Use (MBTU)

-300,000

-250,000

-200,000

-150,000

-100,000

-50,000

0

UE - Recycling UE - WTE

Urban East Region – SOx Emissions (kg/yr)

-300,000

-250,000

-200,000

-150,000

-100,000

-50,000

0

UE - Recycling UE - WTE

Application to EPA’s New Facility in the Research

Triangle Park, North Carolina• Comparison of composting

versus landfilling of non-recycled biodegradable waste

• Facility houses 2,200 people, 400 labs, conference center, cafeteria, national computer center, and childcare center

Scenarios Evaluated Scenarios: 1. Collection, transfer station, and

long haul to regional landfill ~145 km from EPA

2. Collection/transport to compost facility ~ 96 km from EPA

3. Collection/transport to site ~2 km from EPA

Organic Waste Generated: ~160 tonnes of organic

waste including food and yard waste, mixed paper, and animal bedding

Annual Dollar Cost

0

5,000

10,000

15,000

20,000

25,000

30,000

Landfill Compost - Onsite Compost - Offsite

Carbon Equivalents (tons/yr)

0

2

4

6

8

10

12

Landfill Compost - Onsite Compost - Offsite

Annual Energy Use (MBTU)

0

50

100

150

200

250

Landfill Compost - Onsite Compost - Offsite

Particulate Matter (kg/yr)

0

2

4

6

8

10

12

14

Landfill Compost - Onsite Compost - Offsite

Findings from MSW-DST Scenario 1 (landfill option) is highest

emitter of greenhouse gases due to• fugitive landfill methane and • collected gas is flared (no energy

recovery; no offsets for fossil fuel conservation)

Scenario 2 (composting off-site) is least energy efficient due to

• long hauling distance and• Inefficient transport of waste

Scenario 3 (compost on-site) is most desirable option and discussions are underway to identify/develop near-by facility for future use

Evaluation of GHG Emissions Over Time from Solid Waste

Management in the U.S.• Study conducted for U.S. Conference of

Mayors to determine trends in GHG emissions comparing waste management practices over time

• Compared actual GHG emissions today versus what would be emitted if 1970s waste management practices still existed

Analysis of Trends in Greenhouse Gas Emissions for U.S. Solid

Waste Management

1974

2000 2000 with 1974

Technology Waste Management Technology MMTCE/year MMTCE/year MMTCE/year

Collection/Transportation 0.53 0.92 0.77 Recycling -1.1 -6.7 -2.6 Waste-To-Energy -4.9 Landfilling 36 21 53 Total 35 10 51

Net GHG Emissions in the U.S.

0.00E+00

1.00E+07

2.00E+07

3.00E+07

4.00E+07

5.00E+07

6.00E+07

1970 1975 1980 1985 1990 1995 2000

Year

Met

ric T

ons

Car

bon

Equi

vale

nts

(MTC

E)

Net GHG Emissions

Actual Integrated Waste Management Technology path

41 MMTCE avoided

1974 Technology path

Recycling

-8.00E+06

-7.00E+06

-6.00E+06

-5.00E+06

-4.00E+06

-3.00E+06

-2.00E+06

-1.00E+06

0.00E+001970 1975 1980 1985 1990 1995 2000

Met

ric T

ons

Car

bon

Equi

vale

nts

(MTC

E)

GHG Emissions from Recycling

Actual Integrated Waste Management Technology path

4 MMCE avoided

1974 Technology path

Year

Landfills

0.00E+00

1.00E+07

2.00E+07

3.00E+07

4.00E+07

5.00E+07

6.00E+07

1970 1975 1980 1985 1990 1995 2000

Year

Met

ric T

ons

Car

bon

Equi

vale

nts

(MTC

E)

GHG Emissions from Landfills

Actual Integrated Waste Management Technology path

32 MMTCE avoided

1974 Technology path

Waste-To-Energy

GHG Emissions from Waste-to-Energy

-6.00E+06

-5.00E+06

-4.00E+06

-3.00E+06

-2.00E+06

-1.00E+06

0.00E+00 1970 1975 1980 1985 1990 1995 2000

Year

Met

ric T

ons

Car

bon

Equi

vale

nts

(MTC

E)

GHG Emissions from Waste-to-Energy

Actual Integrated Waste Management Technology path

5 MMTCE avoided

1974 Technology path

Note: Negative emissions indicate "savings" in emissions due to energy recovery

U.S. GHG Emissions Avoided

(Year 2000)

Increasing Recycling

Increasing Waste-to-Energy

Increasing Landfill Gas Controls and Waste Diversion

TOTAL AVOIDED

4 MMTCE

5 MMTCE

32 MMTCE

41 MMTCE

Other Ongoing Studies

• RTI is conducting study for State of California comparing “waste conversion” technologies to recycling, landfilling and waste-to-energy

Waste Conversion for BioenergyRenewable Syngas from Biomass Residuals

Tipping Floor Autoclave Recyclables Recovery

ElectricalGeneration

Gasifier

MixedMSW

OrganicPulp

Other Ongoing Studies

Understanding benefits and impacts of Expanding or cutting back recycling

programs (including curbside recycling program and identification of what to include)

Long haul of waste to large regional landfills Existing programs and opportunities for

reducing costs and environmental burdens

Next Steps• Developing web-accessible version of the

MSW-DST• Updating emission factors for landfills• Finalizing partnerships in ensuring he integrity

of MSW-DST is maintained over time• Providing training and technical support to

user community• Release of final project report and journal

articles providing results of case studies

Contacts

Project Web Site – www.rti.org(Search under Municipal Solid Waste)

Keith WeitzResearch Triangle Institute

kaw@rti.org

Susan ThorneloeU.S. Environmental Protection Agency

Thorneloe.Susan@epa.gov

Summary• Computer-based version of the

tool is available for use through RTI

• Work underway to develop web-accessible version of the tool

• Over 30 studies conducted to date and this number will significantly increase once web-accessible version of the tool is available

• We think that significant costs and environmental improvements can be found through taking a holistic approach to environmental management