Smart waste management makes dollars and sense in mitigating climate change.

By Jan Canterbury

It is common knowledge that reducing waste by recycling and composting eases the strain on landfills and the need for raw materials. Increasingly, however, science is showing that these environmentally sound waste management practices do more than save dollars and precious natural resources. The adoption of ecological waste management practices is a viable means for mitigating global climate change.

Waste managers are proving to be the leaders in the fight to reduce the nation’s emissions of greenhouse gases (GHGs). Not only is the nation–in fact, the world–benefiting from reduced climate impacts, but waste managers also are improving the bottom lines of their operations.

"Innovative waste managers and planners should be commended for their efforts," remarks Henry Ferland, program coordinator for the United States Environmental Protection Agency’s (EPA) Climate and Waste Program. "More and more they are capitalizing on the terrific opportunity to reduce greenhouse gas emissions while increasing the cost-effectiveness of their programs. It’s a win-win situation."

Linking Climate and Waste

While global warming has become a buzzword in the media and a source of global political debate, the reputation of climate change (the more accurate term) as a serious and growing international concern is warranted. The link between temperature changes and GHG concentrations in the atmosphere is becoming increasingly clear. Today global climate models project that, by 2100, global surface temperature will rise from 2.5ºF to 10.4ºF and sea level will rise between 3.5 and 35 in., relative to 1990 levels.

Emissions of GHGs from waste products occur as carbon dioxide, nitrous oxide, and methane are released during collection, transport, and final disposal in landfills or incinerators. These "downstream" emissions associated with landfills and combustion account for more than 3% of the nation’s total GHGs. Landfills alone contribute more than one-third of total US methane emissions. Reducing methane emissions can have a strong impact on mitigating climate change, since methane is approximately 21 times more effective at trapping heat in the atmosphere than is carbon dioxide.

But the link between waste management and climate protection is stronger than commonly recognized. Waste management activities have effects that reach far upstream in the life cycle of the materials that eventually become waste. Emissions of carbon dioxide and other GHGs are produced during the extraction of virgin materials and then during the manufacturing process as a consequence of producing virgin paper and wood products. The removal of forests and soil from service as carbon sinks causes additional climate impacts.

Integrated waste management strategies that promote reuse, recycling, and composting eliminate or reduce upstream emissions associated with the acquisition of raw materials and manufacturing of products. In addition, these activities reduce downstream emissions from waste disposal by significantly reducing the quantity of MSW sent to landfills and incinerators.

Reducing GHGs, Improving Bottom Lines

A draft report by EPA’s Office of Solid Waste estimates that waste management options with no net cost–or even cost savings–potentially could provide annual reductions of more than 12 million metric tons of carbon equivalent (MMTCE). This amount is roughly equivalent to the annual emissions generated by 8.8 million passenger vehicles. If the US were to increase its recycling rate to 35% (EPA’s goal for 2005), the total GHG savings would be nearly 43 MMTCE and energy savings would equal 903 trillion Btu.

Pay As You Throw

In Pay As You Throw (PAYT) programs, also known as unit pricing or variable-rate pricing programs, residents are charged for the collection of MSW based on the amount they throw away, creating a direct economic incentive to recycle more and to generate less waste. The GHG benefits include both reduced landfill methane emissions and energy savings associated with waste prevention and recycling (i.e., the decreased need to manufacture from virgin materials).

The City of San Jose, CA (population 920,000), implemented a PAYT program in 1993. Since then the volume of recyclables and yard trimmings diverted from the landfill has tripled. "Our program capitalizes on the fact that financial incentives to recycle serve as very strong motivators," states Michael Foster, associate environmental services specialist for the city’s Environmental Services Department.

San Jose’s citywide PAYT program, with participation from 280,000 single-unit and multiunit households, currently diverts an estimated 53% of MSW from the landfill. To up the ante on reducing waste, in July 2002 the city switched from source-separated to commingled-recycling collection and promoted the use of new 20-gal. mini-garbage carts at reduced rates. The PAYT program, combined with other innovative changes such as the use of split-body trucks that use alternative fuels, is expected to save the city an estimated $90 million over the next 11 years. (The article "Commingled Recycling" in the May/June 2002 issue of MSW Management discusses in detail the commingled recycling project and the city’s new split-body trucks .) "The Pay As You Throw program has brought our city and its residents significant cost savings since its very inception," notes Foster. "By benefiting the environment and our wallets, it’s been overwhelmingly well received by the community."

EPA estimates that the number of communities using PAYT in the US has risen to more than 5,000, involving in excess of 36 million residents throughout the country. Knowing that PAYT programs reduce waste generation and increase recycling, it is possible to quantify the climate benefits of the program. The climate-change benefit from all PAYT programs in 2000 is estimated at more than 3 MMTCE, roughly equivalent to the emissions released from the generation of electricity for nearly 967,000 residential homes for one year.

To further the environmental benefits afforded by PAYT programs, EPA provides technical and outreach assistance to waste managers and local planners across the US by distributing information and offering technical assistance to foster the development of more PAYT programs throughout the country. To find out more, visit www.epa.gov/payt.

San Francisco’s Enhanced Recycling Program

In addition to PAYT, San Francisco also provides another example of smart waste management with climate benefits. The city has improved its PAYT recycling program to include citywide collection of food scraps and other organic materials for composting–the first large-scale project of its kind in the country. Through regular curbside collection of organic materials from homes, apartments, commercial buildings, and restaurants, the program sends approximately 200 tpd of organic materials to a Bay Area composting facility.

By avoiding the production of methane gas from decomposition in landfills, diverting food scraps from landfills reduces GHG emissions by an estimated 43 metric tons of methane each week. This climate benefit will increase dramatically by mid-2003, when citywide rollout of the program is expected to be complete. The program, operated by Norcal Waste Systems Inc., already has reached more than half of the city’s houses and one-third of all restaurants. An additional 1,500 homes and businesses are brought into the program every week.

"This program makes recycling easier and offers people a convenient way to participate in a program that directly benefits the environment," points out Robert Reed, director of corporate communications for Norcal Waste. "Recyclables go in a blue cart, and anything compostable goes in a green cart. About the only garbage left [are things like] broken coffee cups and worn-out tennis shoes."

The compost program accepts all kinds of organics, including post-consumer food scraps (including those with meat), paper soiled with food, waxed cardboard, wood crates, animal bedding, and yard trimmings. These materials are mixed, ground, and composted in enclosed aerated static piles (Ag-Bag composting systems) for two months, windrow-turned and cured for a month or more, and then screened to three-eighths of an inch in size. The finished compost is sold to landscaping and agricultural users, and used for highway erosion control projects. Compost also is being used on organic farms to grow produce sold to Bay Area residents and restaurants, effectively closing the recycling loop locally.

Approximately 75% of San Francisco’s organic waste diverted from the landfill is from the commercial sector, particularly restaurants. Under the new program, separated organics are collected for a 25% discount off the regular rate. Some restaurants report saving more than $600 per month on disposal costs. This direct economic incentive has led to high participation rates and diversion rates as high as 70-90%.

The city aims to divert 75% its waste from landfills by 2010, and 100% by 2020. These ambitious goals are being achieved slowly not only through composting but also through improved recycling. San Francisco has implemented single-stream recycling to facilitate and increase participation. The city also increased the size of recycling containers. These improvements have raised the diversion of recyclables by at least 20%. In addition to increasing the size of recycling bins, the city also has decreased the size of trash bins. To create incentives, the city now offers reduced monthly disposal costs for the use of 20-gal. trash carts instead of the standard 32-gal. carts (a monthly savings of $3.77). Additionally, the city has spent more than $30 million on its recycling facility, making it perhaps the most sophisticated in the country. Known as Recycle Central at Pier 96, it is complete with state-of-the-art mechanical sorting lines that can process up to 1,300 tpd of recyclables.

The city also designed a new collection fleet for the co-collection of trash and recycling. These vehicles are semiautomatic, with vertically split, dual-compartment, side-loading compactors. This setup reduces the number of waste collection trips, saving time, money, and excess emissions of GHGs.

Additionally, the city’s 14 long-haul trucks are fueled with liquefied natural gas, decreasing emissions of carbon dioxide, hydrocarbons, and nitrogen oxides. The city’s entire transport fleet of more than 30 vehicles is scheduled to be converted to natural gas. To fuel these trucks, Norcal built the first liquefied natural gas fueling station in the Bay Area.

Furthermore, some of the city’s pickup trucks are electric while others have modifiers on the exhaust pipe to reduce emissions. These fleet changes can bring significant climate benefits, since the collection and transport of waste to landfills and recyclables to processing facilities contribute an estimated 9% of the total GHG emissions from solid waste management in the US.

In addition to the climate advantages, San Francisco could benefit economically over the long-term through the marketing of collected materials, depending on what the markets have in store. Furthermore, the cost per ton for the compost and recycling collection is less than it is for trash. Indeed, although the program cost an estimated $100 million in infrastructure, monthly waste disposal costs in San Francisco are still considerably lower than the Bay Area average for residential consumers.

"The City of San Francisco places a strong emphasis on recycling and waste reduction efforts that help minimize the city’s need for landfill disposal," stresses Norcal’s Reed. Avoiding landfill disposal is economically important, as significant costs are associated with purchasing additional landfill space or property, siting and permitting, and construction of a new landfill in the Bay Area. Thanks to the city’s innovations, these costs will be significantly delayed.

Compost as Landfill Cover

Since 1998, EPA has been working with Waste Management Inc. to test the feasibility of using compost as a landfill cover to reduce methane emissions. Covering closed landfills with compost provides an excellent environment for the bacteria that oxidize methane. Under optimal conditions, compost covers can practically eliminate methane emissions.

Waste Management is piloting the use of compost landfill covers at one of its recycling and disposal facilities in Louisville, KY. The company is monitoring the cover to provide information on how it reacts to varied weather conditions, temperatures, and the physical stresses of a landfill environment. Waste Management also is assessing the economic benefits of using compost as a landfill cover and will adjust project design accordingly to maximize cost-effectiveness. All studies are expected to be complete by summer 2003, but the latest findings were released at the 7^th Annual Solid Waste Association of North America Landfill Symposium in Louisville. For more information, see the conference proceedings at www.swana.org.

Widespread adoption of this practice by landfill owners and operators would increase the market for compost, thereby creating economic benefits, diverting additional organic materials from landfills, and further reducing methane emissions.

In previous research conducted by Austrian scientists, compost covers were found to completely oxidize methane released from a 10-year-old landfill site more than 65 ft. deep. In addition, the effectiveness was found to improve over time, as the outer layer dries out and creates a barrier that prevents temperature loss in the lower compost layer, improving conditions for methane oxidation. The best results were yielded by matured compost containing solid organic matter with low ammonium and salt concentrations, adequate pore volume, and easily available nutrient supply.

Using compost as a landfill cover is a promising methane control strategy for landfills, especially considering that optimized landfill gas (LFG) recovery systems generally collect only about 70-85% of the total methane generated. Compost covers might be particularly well suited to small landfills, for which LFG-to-energy projects might not be economically viable.

How to Get the Biggest Bang for Your Buck

With so many options for reorienting waste-related activities to reduce emissions, waste managers and planners could use some help identifying which alternative approaches will bring about maximum emission reductions and cost-effectiveness. Waste managers and planners now have a number of tools to help them select the appropriate strategy that will work best for them.

Three software programs, varying in cost and complexity, provide information on the environmental impacts of current practices versus alternative measures: EPA’s WAste Reduction Model, the International Council for Local Environmental Initiatives’ (ICLEI) Greenhouse Gas Emission Software, and EPA’s MSW Decision Support Tool.

EPA's WAste Reduction Model

The WAste Reduction Model (WARM) is a software tool developed by the EPA Climate and Waste Program. WARM enables the user to compare easily the GHG emissions associated with business-as-usual waste management practices to alternative strategies. The software is ideal for identifying and tracking voluntary reductions in emissions and comparing the impacts of different approaches.

WARM covers 21 types of waste materials and five waste management options (source reduction, recycling, composting, combustion, and landfilling). WARM also takes into account several variable site-specific inputs, such as transportation distances to disposal and recycling facilities, LFG recovery, and energy generation.

WARM users input data on the amount of waste by material type and management practice. The software then instantly calculates the associated emissions in metric tons of carbon equivalent or metric tons of carbon dioxide equivalent for both baseline and alternative scenarios. The difference between alternative and baseline emissions represents the benefits of altering a waste management practice. WARM was revised recently to include energy information for waste management practices. Now users can calculate the energy savings associated with their efforts in addition to the GHG savings.

The software is available free of charge in both a Web-based calculator format and a Microsoft Excel spreadsheet. The Excel version allows for breakdown of emissions by type of GHG. WARM can be accessed at www.epa.gov/globalwarming/actions/waste/warm.htm.

GHG Emission Software

The Cities for Climate Protection (CCP) Greenhouse Gas Emission Software is designed for local governments by Torrie Smith Associates Inc. for ICLEI.

The Windows—based software provides an inventory of GHG emissions and an analysis of measures to reduce GHGs on both a communitywide basis and municipal operations alone. The communitywide modules look at residential, commercial, and industrial buildings and processes, transportation, and community-generated waste and recycling. The municipal operations modules look at city-owned buildings, city fleets, and waste and recycling from municipal in-house operations.

CCP software subscriptions, including technical support, are available for a subsidized price of $240 to cities, towns, and counties that are members of ICLEI. Non-CCP members can access the software for the full retail price of $2,000 from Torrie Smith Associates. A similar version of the software, eMission, which does not have the communitywide module but does cover multiple locations anywhere in the world, is available for use by private businesses and institutions. Visit www.torriesmith.com for more information.

MSW—Decision Support Tool

EPA’s Office of Research and Development and the Research Triangle Institute developed the MSW—Decision Support Tool (DST) for use by waste planners at state and local levels. The MSW-DST allows for analysis and comparison of strategies with respect to relative costs, energy consumption, and environmental releases to the air, land, and water. This tool calculates not only projected emissions of GHGs and criteria air pollutants but also emissions of more than 30 air- and water-borne pollutants.

The MSW-DST is designed to model emissions associated with the entire gamut of municipal waste activities, including emissions from transfer stations, material recovery facilities, compost facilities, landfills, and combustion and refuse-derived fuel facilities. The MSW-DST can be used to perform complex analyses, such as how to divert 50% of landfill waste by 2010 most efficiently.

The MSW-DST is offered on a case-by-case basis. A Web-based version of this tool is expected to be released within the next year. The cost varies, depending on the specific needs of the user, but generally starts at upward of $5,000.

Additional Sources of Help

EPA’s WasteWise voluntary partnership program is emphasizing climate reduction strategies for its 1,200 government, business, and industrial partners. WasteWise’s Climate Campaign includes new recognition and award opportunities, access to the WARM software, assistance in measuring climate accomplishments, a series of publications and films on climate change and waste, and onsite assistance in developing climate mitigation strategies. For more information, contact WasteWise at www.epa.gov/wastewise or 800/EPA-WISE.

The Path Forward

With strategic planning, the impacts of waste on our warming planet can be reduced significantly. Even continuing along a business-as-usual path, national recycling rates are projected to increase to roughly 35% in 2005 and 50% in 2020.

These improvements are impressive. But waste managers can and have been going beyond business-as-usual practices, daring to show leadership in environmental stewardship and innovation. Experience has shown that the waste sector is full of "low-hanging fruit" options for cutting emissions that contribute to global climate change. These options are tried and true and limited only by the waste manager’s own creativity and ambition. The opportunities await you.

Jan Canterbury is an environmental scientist with the US Environmental Protection Agency Climate and Waste Program in Washington, DC.

MSW - September/October 2002