Feasibility of Utilizing Acid Mine Drainage Sludge in an Innovative Iron based Wastewater Treatment Process
Acid mine drainage (AMD) is a common pollution source in coal and mineral producing regions, requiring treatment to comply with pollution control regulations. In the Appalachian Basin of the U.S. mine drainage is produced in vast quantities at both abandoned and current coal mining and preparation facilities. Clean Water Act section 402 permits regulate pollution discharge and specify allowable concentrations of iron (Fe) aluminum (Al) manganese (Mn) pH, and suspended solids. Common compliance treatment consists of acid neutralization, mechanical oxidation, and settling of metal precipitates. These precipitates consist largely of hydroxides of the target metals and are collected in settling basins while treated water is decanted to discharge. Initially formed AMD sludge is about 99% water (Skousen and Ziemkiewicz, 1995) and depending on the treatment and storage process, the sludge may reach solids concentrations of 15% to 35% In a previous study, our research team estimated regional sludge production to be about 2.3 million tons/year. Disposing the sludge materials currently represents an environmental and economic burden.