Ash pond
[2] Ash ponds use gravity to settle out large particulates (measured as total suspended solids) from power plant wastewater.
[3] The ponds generally have not been built as lined landfills, and therefore chemicals in the ash can leach into groundwater and surface waters, accumulating in the biomass of the system.
Substances commonly found in coal ash include arsenic, barium, beryllium, boron, cadmium, nickel, lead, mercury, molybdenum, selenium and thallium.
Because of biomagnification, the concentration of unwanted chemicals in animals can increase up a food chain (similarly to mercury in tuna).
[19] As of 2012 there were over 470 operational coal-fired power plants in the US, and approximately 60 percent of US coal ash was disposed in surface impoundments and landfills.
[23] A 2019 report by the Environmental Integrity Project stated that for U.S. coal-fired plants with available monitoring data, 91 percent of them have contaminated groundwater with "unsafe levels of toxic pollutants.
"[24] Historically, due to few federal and state regulations concerning ash ponds, most US power plants do not use geomembranes, leachate collection systems, or other flow controls often found in municipal solid waste landfills.
Pursuant to the Congressional directive, EPA reported in 2000 that coal fly ash did not need to be regulated as a hazardous waste.
The agency continued to classify coal ash as non-hazardous (thereby avoiding strict permitting requirements under RCRA Subtitle C), but with new restrictions: Some of the provisions in the 2015 CCR regulation were challenged in litigation, and the United States Court of Appeals for the District of Columbia Circuit remanded certain portions of the regulation to EPA for further rulemaking.
[30] The regulation limits discharges of toxic metals from power plants, including ash ponds and other wastestreams.
[34] Following a court remand, EPA published its "CCR Part A" final rule on August 28, 2020 requiring all unlined ash ponds to retrofit with liners or close by April 11, 2021.
Some facilities may apply to obtain additional time—up to 2028—to find alternatives for managing ash wastes before closing their surface impoundments.
[35][36][37] EPA published its "CCR Part B" rule on November 12, 2020, which allows certain facilities to use an alternative liner, based on a demonstration that human health and the environment will not be affected.
[38] On January 11, 2022 EPA announced an enforcement action involving ash ponds at certain coal-fired plants in Indiana, Ohio, Iowa and New York.
