Assessment of combustion residual leachate: Local treatment needs and critical mineral recovery

Abstract

Combustion residual leachate from landfills and impoundments at coal-fired power plants represents a large volume of wastewater with variable treatment requirements prior to discharge. Treatment to meet these requirements can be costly, but simultaneously creates an opportunity to co-extract critical minerals. This work first characterizes the treatment needs by developing composite regional standards for 14 contaminants across the United States (U.S). We then assess data on leachate composition and present the total mineral mass and total market size that can be recovered during treatment. Magnesium has the largest total mineral mass and largest market size and can be extracted using commercially available technology. The average simulated value of this magnesium is $38 million from landfill leachate and $660 million from impoundment leachate. This would account for 9 % and 150 %, respectively, of U.S. annual consumption of magnesium.