Q.

What happens inside a modern waste-to-energy facility?

A. The energy value of MSW can be recovered through waste-to-energy (WTE) incineration. Modern energy recovery facilities burn MSW in special combustion chambers, then use the resulting heat energy to generate steam or electricity. This process reduces the volume of MSW to be landfilled by as much as 90 percent. In 1997, there were 112 energy recovery facilities operating in 31 states throughout the United States with a designed capacity of nearly 101,500 tons per day.
Energy recovery facilities are designed to achieve high combustion temperatures that help MSW burn cleaner and create less ash for disposal. Modern air pollution control devices -- wet or dry scrubbers along with electrostatic precipitators or fabric filters -- are used to control and reduce potentially harmful particulates and gases from incinerator emissions.

 

Q.

Are plastics safe in waste-to-energy incineration?

A. Yes. Experts agree that properly equipped, operated and maintained facilities can meet the latest U.S. standards for air pollution control, among the toughest standards in the world. Plastics are a safe and valuable feedstock for these facilities.
Although some activists have suggested there is a link between certain plastics and increased dioxin emissions from w-t-e facilities, a blue-ribbon panel convened by the U.S. Conference of Mayors in 1989 found no evidence to support this claim. A 1995 report from the American Society of Mechanical Engineers reached the same conclusion.

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Q.

How do plastics contribute to waste-to-energy incineration?

A. Plastics are typically derived from petroleum or natural gas giving them a stored energy value higher than any other material commonly found in the waste stream. In fact, plastics commonly used in packaging can generate twice as much energy as Wyoming coal and almost as much energy as fuel oil (see chart below). When plastics are processed in modern WTE facilities, they can help other wastes combust more completely, leaving less ash for disposal.

Energy Values
Material
Btu / Pound
Plastics:
   • Polythlene
   • Polypropylene
   • Polystyrene
Rubber
Newspaper
Leather
Corrugated Boxes (Paper)
Textiles
Wood
Average of MSW
Yard Waste
Food Waste
Heat Content of common fuels
   • Fuel Oil
   • Wyorring Coal

19,900
19,850
17,800
10,900
8,000
7,200
7,000
6,900
6,700
4,500 to 4,800
3,000
2,600

20,900
9,600