Trash-to-energy plant
From Biocrawler, the free encyclopedia.
A waste management facility which uses burns to produce electricity. It is most commonly called a waste-to-energy plant. Most waste-to-energy plants burn municipal solid waste, but some burn industrial waste. Landfill gas and digester gas plants are sometimes included in this category, but are usually considered separately.
Modern waste-to-energy plants should not be confused with the trash incinerators that were commonly used until a few decades ago. Those plants usually did not remove hazardous or recycleable materials before burning. In fact, the process used was not that much different from burning trash in an open pit. Also, most did not generate electricity.
A modern, properly run waste-to-energy plant sorts material before burning it and can co-exist with recycling. In fact, recycling rates are typically higher in areas that have waste-to-energy plants. Items that are not recycleable, by design or economically, and are not hazardous can be sent to the plant for burning. In addition, the plants allow the previously unrecycleable metals integrated into products to be captured. They are collected from the bottom of the furnace and sold to refineries. Modern waste-to-energy plants are specially designed to reduce the formation of new pollutants in the furnace, such as NOx, and to destroy pollutants present in the trash. Pollution control measures, such as baghouses and scrubbers capture most of the rest. Some plants store the waste in an enclosed area with a negative pressure, which prevents unpleasant odors from escaping, and the air drawn from the storage area is sent through the furnace or a filter. Unfortunately, not all plants are operated in the best possible manner and the concerns and complaints of nearby residents are legitimate.
Like all power plants, there is always some level of pollution. Waste-to-energy plants emit more pollution than natural gas pollutants, but less than coal, which produces half of the electricity in the United States. A few plants use gasification, which is thought to be less polluting, perhaps incorrectly, but most combust the waste directly because it is a mature technology. Waste-to-energy plants also reduce the volume of waste by 80 to 90%. If it is put in the landfill it greatly extends its life, and sometimes the waste is clean enough to be used for other purposes.
Burning waste does produce dioxin. How much dioxin is greatly debated. Advances in design and new regulations have caused large reductions in the amount of pollution produced by waste-to-energy plant, particularly dioxin. A good point is made that it produces more dioxin than other forms of energy, such as natural gas. Also, solar, wind and hydroelectric power do not produce dioxin at all. Others believe that the amount of pollution produced is offset by the landfill space saved, metal captured, pollutants destroyed in the furnace and the electricity produced, which might have otherwise been produced at a coal plant less cleaner than the waste-to-energy plant. Finally, waste-to-energy plants replace the burning of landfill gas. The gas contains about 50% methane, 50% carbon dioxide, is contaminated with a small amount of pollutants. Unlike at waste-to-energy plants, there are little or no pollution controls on the burning of landfill gas, which is usually flared or used to run a reciprocating engine or microturbine. Cleaning up the landfill gas is usually not cost effective because natural gas, which it substitutes for, is relatively cheap. However, it might be a better solution to regulate landfill gas burning than to use waste-to-energy plants.
