New software and management techniques can help reduce methane and minimize greenhouse gases.
Managing landfill gas can be an expensive item on the balance sheet, but it also is taking its toll on the environment, specifically greenhouse gas emissions that contribute to global warming. However, by using steps at the beginning and the end of the waste management process, plus a few newly created software programs, waste managers can improve the bottom line and our environment at the same time.
Landfills account for the lion's share of methane emissions. Keep in mind that carbon dioxide and methane together account for approximately 90 percent of all U.S. greenhouse gas emissions, although landfills account for only 4 percent of that total. Methane, however, is 22 times more potent as a greenhouse gas than carbon dioxide.
Three software programs now are available to help determine which management strategy can produce the greenest bang for the buck. Varying in cost and complexity, the tools provide information on the environmental impacts of current practices vs. alternative measures.
The WAste Reduction Model (WARM) software tool was developed by the U.S.'s (EPA) Climate and Waste Program, Washington, D.C., and identifies and tracks voluntary emissions reductions, then compares the effects of the different approaches. It enables you to compare greenhouse gas emissions from business-as-usual waste management practices with emissions from alternative strategies.
Covering 17 types of waste materials and 5 waste management options (source reduction, recycling, composting, combustion and landfilling), WARM also takes into account several variable site-specific factors, such as transportation distances to disposal and recycling facilities, landfill gas recovery and energy generation.
WARM users input data on the amount of waste by material type and management practice. Then WARM, using a web-based calculator or Microsoft Excel spreadsheet, calculates the emissions in metric tons of carbon equivalent for each scenario, both baseline and alternative. The difference between alternative emissions and baseline emissions represents the benefits of altering a waste management practice.
The Excel version also helps you break down emissions by greenhouse gas type.
WARM is available at www.epa.gov/mswclimate.
The Cities for Climate Protection (CCP) Campaign Greenhouse Gas Emission Software was designed for local governments to provide analyses community-wide, and for municipal operations alone. Developed for the International Council for Local Environmental Initiatives (ICLEI), the community-wide module considers residential, commercial and industrial buildings; transportation; and community-generated waste. The municipal operations module factors in municipally owned buildings, city fleets and waste from municipal in-house operations.
In addition to computing greenhouse gas emissions, the Windows-based CCP software estimates reductions in criteria air pollutants and changes in energy consumption. It also calculates financial costs and savings from energy use.
Pre-formatted charts and reports help you develop cost-effective plans to monitor progress. A similar version of the software, eMission, is available for use by private businesses and institutions.
CCP software subscriptions, including technical support, are available to governments that are members of ICLEI for $240. Non-CCP members can access the software for $2,000. The price for businesses and institutions is $995.
MSW Decision Support Tool
The MSW Decision Support Tool (DST) is being developed by EPA's Office of Research and Development and the Research Triangle Institute in Research Triangle Park, N.C., to assist local and state waste planners analyze and compare alternative methane-reduction strategies in terms of relative costs; energy consumption; and environmental releases to the air, land and water. The tool calculates projected emissions of greenhouse gases and criteria air pollutants, as well as emissions of more than 30 air- and water-borne pollutants.
The DST is designed to model emissions from the gamut of municipal waste facilities. The DST can be used to perform analyses, such as predicting the costs of recovery from a local to a regional landfill while implementing a specific policy goal, such as diverting 40 percent of landfill waste by 2005.
This modeling tool has not yet been released but is offered by the EPA on a case-by-case basis. Costs vary, but generally start at $10,000, depending on the user's needs.
Alternatives to Creating Waste and Methane
In addition to the software programs, other programs may offer ways to reduce greenhouse gas emissions from MSW.
For instance, since 1998, EPA and., Houston, have tested the feasibility of using compost as a landfill cover to reduce methane emissions.
For example, Waste Management is monitoring its use of compost covers at one of its Kentucky facilities to see how it reacts to varied weather conditions, temperatures and the physical stresses of a landfill environment. Waste Management already has begun assessing the cover's economic benefits and expects to have the results completed by summer 2002.
In similar research conducted by Austrian scientists, compost covers resulted in complete decomposition of the methane released from a 10-year-old landfill site more than 65 feet deep. Results exceeded typical landfill gas recovery systems, which generally collect about 70 to 85 percent of the total gas generated.
Additionally, the compost's effectiveness was found to improve with time. As the outer layer dries up, it creates a barrier that prevents temperature loss in the lower compost layer, which then improves methane oxidation conditions. Mature compost containing solid organic matter with low ammonium and salt concentrations, adequate pore volume and easily available nutrient supply was found to yield the best results.
The EPA and industry is continuing to test using compost as a landfill cover to control methane. So far, the agency has found that the economics of landfill gas-to-energy projects may not be attractive at the sites where gas collection isn't required. However, as more landfill owners adopt this practice, the market for compost would increase, while diverting additional organic materials from landfills and reducing methane.
Pay-as-you-throw (PAYT) programs — charging residents for collection based on the amount left at the curb — is another way that has proven to reduce waste and the methane it eventually creates.
For example, since the PAYT program was implemented in San Jose, Calif., in 1993, the volume of recyclables and yard trimmings diverted from the landfill has nearly doubled. The city-wide program, which involves 280,000 households, diverts a total of 51 percent of municipal solid waste from the landfill, according to Ellen Ryan, deputy director of environmental services for the city of San Jose. “Our experience has demonstrated that financial incentives to recycle serve as very strong motivators,” Ryan says.
A similar PAYT effort in Tacoma, Wash. tripled the recycling rate while decreasing MSW costs by more than 50 percent in the program's first year, according to Karen Larkin of the city of Tacoma. Based on a recent study by Skumatz Economic Research Associates Inc., in Seattle, the combined effects of source-reduction, recycling and yard waste diversion reduce residential landfill disposal by a total of 16 to 17 percent.
Since 1994, the EPA WasteWise program has helped more than 1,000 organizations implement programs to prevent waste, collect recyclables and purchase recycled-content products. WasteWise partners range from small local governments to Fortune 1,000 corporations.
Recycling also can affect climate change. For example, 1 ton of recycled aluminum will prevent 13 tons of carbon dioxide from entering the atmosphere, according to the EPA's Office of Solid Waste and Emergency Response.
EPA's Product Stewardship initiative is designed to help manufacturers rethink their products and relationship with the supply chain and customer. Reducing energy consumption, designing products for reuse and recyclability, and creating take-back programs often lead to increases in productivity, cost-reductions and product innovations, while helping companies become better environmental stewards of their products.
As managers of solid waste programs, state and local governments are essential to fostering product stewardship. A few states have incorporated product stewardship goals into their waste management plans and launched cooperative efforts with industry to encourage recycling. For instance, a number of states — California, Florida, Georgia, Iowa, Maine, Massachusetts, Minnesota, New Jersey, North Carolina, Rhode Island, South Carolina, Texas, Vermont and Wisconsin — have developed legislation that incorporates product stewardship goals for selected products. Likewise, industry leaders in several manufacturing sectors, such as automobiles, carpets, batteries, tires, electronics, packaging and building materials, have worked with the EPA to incorporate concepts of product stewardship into their business practices. For example, Sanyo Electric Co. Ltd. has developed an early take-back system for collecting spent rechargeable batteries directly from consumers.
The federal Green Buildings program encourages developers to construct resource-efficient buildings to improve resource conservation, energy efficiency, use of renewable energy and waste minimization. Green Building efforts can be promoted by local and state agencies or adopted independently by individual schools, architects, engineers, construction companies, manufacturing plants, hotels and office buildings.
One-third of all energy and two-thirds of all electricity used in the United States is consumed in 76 million residential buildings and nearly 5 million commercial buildings. The buildings produce 35 percent of national carbon dioxide emissions and therefore contribute significantly to climate change.
With so many tools already available to inventory and reduce greenhouse gases from waste, plus more on the horizon, waste managers are becoming leaders in reducing local wastes while helping to slow greenhouse gas emissions.
Jan Canterbury is an environmental scientist with the U.S. Environmental Protection Agency Climate and Waste Program, Washington, D.C.
Clean Energy Transport
Collecting and transporting waste and recyclables to landfills and processing facilities contribute approximately 9 percent of the total net greenhouse gas emissions from solid waste management, according to Maria Zannes, president of the Integrated Waste Services Association, Washington, D.C. Most of these emissions result from diesel combustion in transport vehicles. Because collection costs typically represent the single largest component of waste management budgets (up to 62 percent), improving collection efficiency can reduce costs significantly.
Two smart solutions can make collection more efficient:
Route Optimization. A 1999 U.S. Environmental Protection Agency (EPA), Washington, D.C., study found that improved routing in selected cities led to annual savings ranging from $26,500 to $452,000. With the help of customer databases and geographic information system (GIS) street maps, compact collection routes can be designed to minimize travel distance. These tools can help equalize workloads between different routes, and streets where traffic tends to be congested, can be avoided.
Landfill Gas as Fuel. The fuel savings gained by converting landfill gas to liquefied natural gas (LNG) for use in waste collection vehicles can offset the approximately $135,000 needed to lease a LNG fueling station.
As diesel prices continue to rise and additional LNG vehicles are added to a community's collection fleet, cost savings are expected to rise even more.
— Jan Canterbury
Where to find the tools to reduce waste management costs and emissions:
- WAste Reduction Model: www.epa.gov/mswclimate
- CCP Software: http://www.torriesmith.com or www.iclei.org
- MSW Decision Support Tool: Keith Weitz of RTI at (919) 541-6973, or Susan Thorneloe of EPA at (919)-541-2709
- Landfill Covers: http://www.wm.com/docs/1/press0081.html and http://www.wm.com/bio.html
- Pay-As-You-Throw: http://www.epa.gov/payt
- WasteWise: 1-800-EPA-WISE (372-9473) or www.epa.gov/wastewise
- Product Stewardship: http://www.epa.gov/epr/ or Clare Lindsay of EPA at (703) 308-7266
- Green Buildings: http://www.sustainable.doe.gov/buildings/top, http://www.nahbrc.org/ or www.usgbc.org.
- ENERGYSTAR?: http://www.energystar.gov/
- Landfill Methane Outreach Program: http://www.epa.gov/lmop
- Smart Savings: http://www.epa.gov/globalwarming/actions/local/smartsavings/index.html
- “Collection Efficiency: Strategies for Success”: http://www.epa.gov/epaoswer/non-hw/muncpl/coll-eff/k99007.pdf