Trash from growing global population is challenge for ASME division

Elio A. Manes
ASME Engineering Programs
Last year, Americans alone were estimated to generate 225 million tons of trash, according to the Integrated Waste Services Association, an American nonprofit organization that promotes integrated solutions to municipal solid waste management problems.

About one-third of American garbage will be recycled or composted, leaving about 150 million tons of garbage to be managed by other methods.

Multiply that amount of trash to be managed by the global exponent, and you get an idea of the size of the challenges that ASME's Solid Waste Processing Division has wrestled with practically since its birth in 1957.

Nearly 3,000 ASME members are interested in how solid waste is being processed globally and in ideas for new solutions to manage it.

Generally, the SWPD endorses an integrated approach to solid waste management; that is, disposing of trash through a concerted effort of land filling, composting, recycling and incineration.

Only about one-third of America's trash is recycled, in plants like this paper recycling facility. The rest of the nation's garbage is either incinerated or dumped in landfills.

But, as John Heffernan wrote in the division's spring 2000 newsletter, when he was chair of SWPD, "While the focus of the past has been on the building and operations of waste-to-energy facilities, current technical issues on air pollution, materials recovery, and regulations and standards have taken the forefront."

And as the new millennium progresses, he wrote, "We will look for continued advancement of newer technologies for processing solid waste."

Already, the division, which once led efforts to manage municipal solid waste by incineration, is working to expand its horizons to the broad field of waste management, including Materials Recovery Facilities and landfill (methane) gas recovery.

"We are trying to attract the medical waste industry," said Judith Stelian, the division's current chair, "where we feel that many of the issues are similar to the ones faced by the solid waste industry."

While the division's mission is to foster developments in the design, construction and operation of waste-to-energy (WTE) incinerators, landfills, composting and recycling facilities, currently WTE plays a big part in SWPD activities.

That's because most of the surplus trash in the United States will end up either in landfills or used as fuel to generate electricity and steam power at WTE facilities.

Currently, 102 waste-to-energy plants operate in 31 American states. They process nearly 30 million tons of municipal trash annually, while producing more than 2,800 megawatts of electricity — enough to power nearly 2.5 million homes.

And because of the environmental benefits of waste-to-energy — WTE facilities are subject to stringent federal emission standards that make energy produced from trash cleaner than conventional coal- or oil-fired power plants — SWPD members believe there will be a renewed interest in the construction of new plants in the United States.

Those environmental benefits, however, will be challenged by some economic hurdles. Low waste disposal and electric energy costs have worked against each other to bring about a decline in the U.S. waste-to-energy market, wrote Amit Chattopadyay in a division newsletter in the fall of 1998 when he was chair. That decline is not as evident globally because most countries have fewer restrictions on WTE facilities.

U.S. interstate commerce laws have made interstate transportation of waste to distant landfills more economical. A reduction in landfill tipping fees made it cheaper to dispose of waste in landfills than processing it at WTE plants. Also, the deregulation of U.S. electric utilities caused WTE plants a loss of revenue from electricity sales.

Although states are doing what they can to provide funds to keep WTE operations viable, engineers in U.S. waste-to-energy business are challenged to devise creative solutions to enhance the operation of existing facilities, in addition to finding entirely new solutions for processing solid waste.

To support that effort, the division disseminates information for advancing the technology and practice of waste management through technical papers, conferences, workshops and public policy statements.

SWPD also gives $9,000 in scholarships to students attending a North American college or university with an established solid waste management program and their schools in support of its solid waste program.

For more information about the Solid Waste Processing Division and its activities, visit its Web site at www.asme.org/divisions/swpd or contact Elio Manes, ASME Engineering Programs Dept., at (212) 591-7797, or e-mail manese@ asme.org.

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