Remediation of acid mine drainage

Acid mine drainage induced by the mining industry causes environmental and economic issues. Acid mine drainage contains mainly metals such as Fe, Al, Cu, Ca, Mg, Mn and Zn. Preventing the formation of acid mine drainage has not been found feasible. As a consequence, remediation treatments have been developed during the last years to remove metals and obtain high-quality water, which may be reused. We review here several treatment options such as selective metal precipitation, adsorption, electrochemical processes and membrane processes. Adsorption is the most employed commercially since it can recover 99% of the metals. Membrane processes are promising according to lab-scale results, notably because high-quality water is obtained. Further research is necessary to implement combination of technologies, e.g., adsorption membrane, at larger scales, as well as to obtain more valuable products that can balance the overall economy for the mining industry.