Incineration has traditionally been the EPA's least favored approach to dealing with solid waste because of the lost resources and the pollutants emitted out the stack. But incineration's cousin, the waste-to-energy (WTE) system, may be redeeming itself because of its best attribute: The energy produced (generally electricity) is a desired commodity used by surrounding communities.
The basic steps in the WTE process that make the critical difference are that the solid waste is burned in a furnace and is channeled into heat tubes of water in a boiler. The high temperatures produced transform the water to steam, the force of which drives a turbine generator, producing electricity. In a clean system, ash particles and harmful chemicals are removed before being emitted as smoke and gases. The heavier ash that falls to the bottom is collected for transport to the landfill, and the remaining gases escape through the stack. It's this last step that still draws attention from detractors. The WTE plane built near Columbus, Ohio, was championed in its early days, even though it was referred to as the "cash-burning plant," says John Remy, director of communication at the Solid Waste Authority of Central Ohio (SWACO), Grove City, Ohio. The plant was designed to burn a combination of coal and the city's trash. The equipment in the plant was touted as state of the art.
Initially, some components broke down, an inherent by-product of innovation, says Remy. Toward the end of its life, it was denounced particularly because of its emissions. For this, the plant got a bad rap and was closed in 1994. Bringing it up to the new standards was judged to be economically unfeasible. Right now it's a gutted shell used for storage.
Dr. John H. Skinner, executive director and CEO of the Solid Waste Association of North America (SWANA), Washington, sees fuel generated by WTE plants as one of the cleanest fuels available, provided current standards are met. The mercury and dioxin standards for WTE plants are far more stringent than those for coal-fired plants, he notes. WTE plants are also cleaner, he assures, "than some sources of oil in terms of oil-fired power plants, especially high-sulfur-content oil. The industry over the last 10 years has gone through a major upgrade in terms of installing pollution control equipment as required by the Clean Air Act."
But is WTE a form of recycling, or does it squander potentially recyclable resources? Critics are concerned that if burning collected material were to become more prevalent, there would he less incentive to take the trouble to recycle.
In some states, such as Massachusetts, New Jersey and New York, no new WTE plants will be considered until recycling is thoroughly in place. Currently, 98 WTE systems are operating in 29 states in the U.S., a number that has decreased in the last few years.
Skinner points to statistics to demonstrate that WTE plants are compatible with recycling. "There's a lot of recycling that goes on in the context of a WTE plant. Metal is often recycled. Quite a few communities have paper recycling programs in conjunction with their WTE plants. The amazing thing, if you look at the statistics on the communities that have WTE plants, is this: The recycling percentage is higher than the national average--35 percent recycling compared to a national average of 30 [percent] to 32 percent."
BURN VS. BURY COSTS. WTE plants are considered more costly to operate than typical incinerators. Not only do emission control costs exceed those of coal burning incinerators, but plant capacity is also greater in a WTE than in a coal burning incinerator. For example, it takes 1 ton of garbage compared to 1/4 ton of coal to produce the same amount of energy, according to the Energy Information Administration, Washington.
Skinner counters that WTE plants are more economical in the parts of the country where landfill costs tend to be high. He cites the densely populated Northeast as well as Florida, where landfilling is limited because of the high water table. There are not as many further west, he notes, "because landfill prices lend to be lower. The big states for WTEs are Virginia, Florida, New Jersey and New York, where landfill costs are higher. For WTEs, $35 to $40 per ton of waste deposited is typical. In the West, landfill prices are $20 to $25 per ton, so it's more expensive. But in the East, land disposal [tipping fees] are above $40 per ton, so in those cases it's competitive."
