According to Earthjustice and Physicians for Social Responsibility, Water and air in 34 states are being poisoned by the waste of coal-fired power plants—creating major health risks for children and adults. The contamination occurring at hundreds of coal ash dumps and waste ponds across the country to health threats such as cancer, nerve damage and impairment of a child's ability to write, read and learn.
Coal ash has different physical and chemical properties depending on the geochemical properties of the coal being used and how that coal is burned.
- “Fly ash” consists of the fine powdery particles of minerals, plus a small amount of carbon, that are carried up the smokestack by the exhaust gases.
- “Bottom ash” is a coarser material that falls to the bottom of the furnace.
- “Boiler slag” is created from the molten bottom ash that, when cooled in contact with water in wet-bottom boilers, forms pellets of a hard, glassy material.
- Flue gas desulfurization (FGD) waste is the byproduct of air pollution control systems used to reduce the sulfur dioxide emissions from coal fired power plants. “Scrubbers” spray lime or limestone slurry into the flue gas, where it reacts with the sulfur to form calcium sulfite that is processed to make FGD or synthetic gypsum.
- Fluidized bed combustion (FBC) wastes are generated by a specialized combustion technology in which a heated bed of sand-like material is suspended (fluidized) in a rising jet of air. FBC waste may include fly ash and bottom ash and tends to be more alkaline because of the limestone used in the process.
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