How it Works
Modern waste-to-energy facilities combust post-recycled waste in a highly controlled and efficient combustion system, recover energy from the combustion process, and are equipped with proven air emission control technologies that minimize potential emissions. Modern waste-to-energy facilities work very differently from old-fashioned municipal "incinerators" that burned trash inefficiently, had minimal, if any, air emission control systems, and did not recover any of the energy released during the combustion process.
The waste-to-energy process in modern facilities starts with incoming trucks delivering trash to an enclosed reception area where trash is unloaded into concrete storage pits. Overhead cranes then transfer the trash into a feed hopper to the boiler. Inside each boiler, an inclined, reciprocating, metal grate slowly moves the trash through a thermal (heating) process, where temperatures exceed 2000°F. The large utility-type boilers recover thermal energy in the form of high-pressure steam, which is then converted into electrical energy in the turbine-generator. With access to existing steam distribution lines, waste-to-energy facilities can produce and sell both steam and electricity. Air that is required to feed the combustion process is drawn from the refuse-receiving building, sustaining a negative pressure that prevents "garbage" odors or dust drom escaping into the outside environment.
After the trash is completely processed, scrap metals are separated from the ash residue for recycling and the overall volume of incoming trash is reduced by more than 90%. The recycled scrap metals help offset the need to mine virgin materials for new products.
Click here to see a waste-to-energy plant at work.
