Pervious concrete for treatment of acid mine drainage: Neutralization of pH and removal of dissolved iron, aluminum, manganese, and copper

Pervious concrete has shown potential in neutralizing wastewater and stormwater, and this study was conducted to determine the effectiveness of pervious concrete at removing heavy metals and neutralizing acid from an AMD source. The removal of aluminum, manganese, iron, and copper from natural and synthetic AMD sources by pervious concrete cubes at beaker scale was tracked. Pervious concrete cylinders were also used to model length requirements for a permeable reactive barrier to treat field-scale AMD. From an initial natural AMD pH of similar to 4.1, approximately 600 min of contact time with pervious concrete was needed to reach a neutral pH. With 24-hrs of exposure to pervious concrete, solutions reached a pH of similar to 8.0 and > 95% of aluminum, iron and copper, and similar to 30% of manganese in natural AMD was removed. Column testing indicated permeable reactive barriers of similar to 8 m in length could treat Al, Fe, and Cu, with results showing a promising argument for the use of pervious concrete in AMD treatment at field scale.