Fly Ash Landfill & Production and Use of Coal Combustion Products Diagram

 Is Fly Ash Landfilled?

Although the chemical and physical properties of fly ash make it ideal for a variety of beneficial applications, it must compete against other inexpensive bulk materials such as sand and gravel, and therefore is economic only where transportation and handling costs can be kept low. As a result about 60% of the fly ash produced in the United States is not recycled for commercial use, but rather is placed in specially designed, permitted landfills.

To prevent impacts on the surrounding environment, modern fly ash landfill sites are carefully selected. The selection process involves topographic mapping, site reconnaissance, an environmental inventory, and surface water and groundwater studies. Sites on flood plains are generally avoided because of potential erosion, as are those near wetlands or on a drainage pathway to a water body, where repeated water exposure could dissolve some trace elements.

Once a site is chosen, the landfill is constructed to be compatible with the local terrain. Where underlying natural soils are very permeable, a clay or plastic liner ensures that the ash does not come into contact with the underlying groundwater.

 

Production & Use of Coal Combustion Products Diagram Based on The American Coal Ash Assocation 2004