Performance and Risks of Acid Mine Drainage Neutralization with Fly Ash from India and the United States

Abstract

Acid mine drainage (AMD) and coal ash disposal can affect the quality of surface and groundwater near mines and disposal sites. Water contamination from AMD is a major cause of environmental and water quality degradation in regions of coal mining in India and the United States. Coal ash contains heavy metals that can be mobilized into water and thus contaminate surface water and groundwater through leaking of coal ash ponds and landfills. Given that AMD is acidic, while coal ash is often alkaline, and both can pose environmental and human health risks, this study examines the possible use of coal ash as a medium for neutralizing the acidity of AMD. The study aims to evaluate if interaction of AMD with coal ash would reduce the environmental impact of AMD. Through systematic experiments reacting fly ash with AMD, I show that some types of calcium-rich fly ash can effectively neutralize AMD, with removal of some contaminants but mobilization of other toxic elements from the fly ash into the neutralized AMD. These results have implications for possible alternative technologies to remediate AMD in India as well as coal ash disposal and management in the United States.