Ash pond

Ash Pond

An ash pond, also known as a coal ash basin, is a type of engineered structure used for the disposal of coal combustion residuals (CCR), commonly known as coal ash. These ponds are typically located at coal-fired power plants and are designed to store the byproducts of coal combustion, which include fly ash, bottom ash, and flue gas desulfurization materials.

Design and Construction

Ash ponds are usually constructed as earthen embankments or diked reservoirs. They are designed to contain the ash slurry, which is a mixture of water and ash. The water in the slurry allows the ash to settle at the bottom of the pond, while the water is either recycled back into the plant or treated and discharged.

The design of an ash pond must consider factors such as the volume of ash produced, the topography of the site, and the potential environmental impacts. Proper lining and monitoring systems are essential to prevent the leaching of contaminants into the surrounding soil and groundwater.

Environmental Concerns

Ash ponds have been a significant environmental concern due to the potential for groundwater contamination and catastrophic failures. The ash contains heavy metals such as arsenic, lead, and mercury, which can leach into the groundwater if the pond is not properly lined.

In recent years, there have been several high-profile ash pond failures, such as the 2008 Kingston Fossil Plant coal fly ash slurry spill in Tennessee, which released over a billion gallons of ash slurry into the surrounding environment.

Regulations and Management

In response to environmental concerns, the United States Environmental Protection Agency (EPA) has implemented regulations to manage coal ash disposal. The Coal Combustion Residuals Rule establishes requirements for the safe disposal of coal ash, including the closure of unlined ash ponds and the monitoring of groundwater.

Power plants are increasingly moving towards dry ash handling systems and the closure of existing ash ponds to comply with these regulations and reduce environmental risks.

Alternatives to Ash Ponds

As environmental regulations become stricter, power plants are exploring alternatives to ash ponds. These include converting to dry ash handling systems, recycling ash for use in construction materials such as concrete, and developing new technologies for ash disposal.

Also see

• Coal Combustion Residuals
• Fly Ash
• Environmental Impact of Coal
• Kingston Fossil Plant coal fly ash slurry spill
• Coal-fired power plant