What is Waste-to-Energy
What is Waste-to-Energy
Modern waste-to-energy facilities differ significantly from old-fashioned municipal incinerators. Incinerators inefficiently burned trash, had minimal air pollution control systems and did not recover any of the energy released during the combustion process.
Modern waste-to-energy facilities recover the heat value of combusted trash to generate steam and electricity-enough in the U.S. to power three million homes.
Wheelabrator's waste-to-energy facilities use proven mass-burn technology to take everyday trash and convert it into clean, renewable electric energy. The process starts with incoming trucks delivering trash to an enclosed reception area and dumping the refuse into a concrete receiving pit. From this area, overhead cranes transfer trash into one of the boilers' feed hoppers. Inside each boiler, an inclined, reciprocating, metal grate (floor) slowly moves the refuse through the combustion process, where temperatures exceed 2000°F, in order to allow complete combustion of the trash to occur. Air to feed the combustion process is drawn from the refuse receiving building, sustaining a negative pressure there. This negative pressure prevents any "garbage" odors or dust from escaping into the outside environment.
Highly efficient combustion reduces the volume of trash by about 90 percent, and advanced pollution control systems ensure a cleaner-burning power plant.
Surrounding the grate system is a large utility-type power boiler designed to recover the thermal energy released during the combustion process. This energy is recovered in the form of high-pressure steam that is converted into electrical energy in the turbine-generator. At full capacity, a waste-to-energy plant that consumes 1500 tons per day of trash has a generating capacity of more than 40,000 kilowatts of electrical energy for sale to the local electric utility company. This is the equivalent of supplying all of the electrical needs of 40,000 homes.
Emissions from the combustion process are controlled using state-of-the-art spray dryer absorbers, also known as dry scrubbers, to control acid gases, heavy metals, and organic pollutants; fabric filter bag houses to collect particulate matter; selective non-catalytic reduction systems to control ozone-forming nitrogen oxides; and activated carbon to control mercury and trace organic emissions. These control systems thoroughly clean emissions to meet all local, state, and federal environmental standards.
Emissions from the combustion process are controlled using state-of-the-art spray dryer absorbers, also known as dry scrubbers, to control acid gases, heavy metals, and organic pollutants; fabric filter bag houses to collect particulate matter; selective non-catalytic reduction systems to control ozone-forming nitrogen oxides; and activated carbon to control mercury and trace organic emissions. These control systems thoroughly clean emissions to meet all local, state, and federal environmental standards. After the garbage is completely processed, the remaining ferrous metals are separated from the residue.
After the garbage is completely processed, ferrous metals are separated from the ash residue. As a result of the combustion and metals recovery processes, the volume of incoming garbage is reduced by more than 90%. Click here to see a waste-to-energy plant at work...
At full capacity, a waste-to-energy plant that consumes 1,500 tons per day of trash will generate more than 40,000 kilowatts of electrical energy for sale to the local electric utility company -- the equivalent of supplying all of the electrical needs of 40,000 homes.
Today, waste-to-energy plants generate enough energy to supply the electricity requirements of millions of households. Nationwide, waste-to-energy facilities process nearly 29 million tons of trash each year and generate enough power to meet the needs of 3 million homes. More than 36 million people in 27 states rely on waste-to-energy plants.
Providing electricity is not the only major advantage of waste-to-energy plants, burning waste also reduces the amount of garbage going to landfills. According to the Energy Information Administration (EIA), a statistical agency of the U.S. Department of Energy, the average American threw away 2.7 pounds of trash a day in 1960. Today, the average American throws away 4.5 pounds of trash daily, an increase of 67 percent.
The EIA also cites that waste-to-energy facilities dispose of the waste of 35 million people. Statistically, the average American produces more than 1,600 pounds of waste a yearly. This amount of waste normally takes up more than two cubic yards of landfill space, the volume of a box three-feet long, three-feet-wide and six-feet high. Conversely, instead of land filling it, the waste can be converted into electricity in a waste-to-energy plant, producing an ash residue fitting into a box nine times smaller.
There is a great need for the safe and efficient combustion of trash to generate the energy we need to power our globe while minimizing adverse impacts to the environment.
