Water recovery from acid mine drainage by electrodialysis

In this study, the possibility of using electrodialysis for the treatment of acid mine drainage generated from coal mining to recover water is investigated. Electrodialysis allows for the separation of anions and metallic cations, possessing the advantages of removing contaminant metals and simultaneously recovering water. To investigate this technology, the passage of anions and cations from three different acid mine drainages through a HDX 200 anion-exchange membrane and a HDX 100 cation-exchange membrane, respectively, was evaluated. The results show that electrodialysis is suitable for recovering water from acid mine drainage, with contaminant removal efficiencies that are greater than 97%. However, the precipitation of iron at the surface of the cation-exchange membrane constitutes a problem for the system by causing a blockage of the membrane through the scaling phenomenon, which reduces the process efficiency.

► AMD presents variable composition, low pH and SO42- in higher concentration.
► Current density in ED tests for treatment of AMD is limited by the anion membrane.
► Method for water recovery from AMD, removing more than 97% of the contaminants.