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Waste-to-energy technology cleans environment in two ways


Americans are dumping a valuable energy resource into landfills. According to the U.S. Environmental Protection Agency, organic material makes up about 75 percent of the 4.4 pounds of garbage the average person throws away every day, and organic material contains energy.

The good news is many communities already harness this resource with waste-to-energy powerplants. The Integrated Waste Services Association identifies 102 such facilities in 31 states, helping cities meet the constant challenge of trash disposal while promoting energy diversity.

Waste-to-energy plants produce clean, renewable energy through the combustion of municipal solid waste in specially designed boilers equipped with the most modern pollution control equipment to clean emissions. The Clean Air Act of 2000 led municipal waste combustors to spend more than $1 billion to upgrade their emissions control systems. Flu gasses run a gauntlet of sophisticated equipment to remove harmful emissions:

  • A baghouse filters the exhaust through hundreds of fabric filter bags to remove soot, smoke and metals.
  • A scrubber sprays lime slurry into the hot exhaust to neutralize acid gases, just as a gardener uses lime to neutralize acidic soil.
    Scrubbing also can improve the capture of mercury in the exhaust.
  • Selective noncatalytic reduction reduces nitrogen oxides – a component of smog – to harmless nitrogen by spraying ammonia or urea into the hot furnace.
  • Carbon injection systems blow charcoal into the exhaust gas to absorb mercury. Carbon injection also controls organic emissions such as dioxins.

Also, since the power from modern waste-to-energy plants usually replaces older oil- or coal-burning technologies, the plants can actually improve the air quality in the communities where they operate.

The U.S. Department of Energy and 15 states, including Minnesota, recognize waste-to-energy as a renewable biomass. Municipal solid waste combustion produces electricity 24 hours a day, 365 days a year. Since the plants generally operate in urban areas, transmission issues are seldom a problem for waste-to-energy generation.

Currently, municipal waste combustors turn about 13 percent of our trash, or 97,000 tons per day, into enough electricity to power nearly 2.3 million homes. As an added bonus, burning reduces trash volume by 80 to 90 percent. The remaining residue is regularly tested and consistently meets strict EPA standards allowing reuse or disposal in landfills.