An Evaluation of the Potential Use of Microbial Fuel Cells for Energy Production and Simultaneous Acid Mine Drainage Treatment

Acid mine drainage (AMD) is a leachate that may occur naturally or be produced at mining sites and tailings deposits. Characteristically, AMD consists of effluents with extremely low pH (4.0) and a high concentration of heavy metals; therefore, it is highly toxic. Due to the impact that these effluents have on the environment, effective and low-cost methods for AMD treatment have been developed. As an important strategy for pH increase and metal-ion precipitation, there are biological treatment methods, in which bioreactors containing biocatalysts, such as sulfate-reducing bacteria, are applied. Regarding the applicability of microbial fuel cells (MFCs) for the treatment of effluents, this technology can be an innovative and promising alternative for AMD treatment. This paper aims to review the biological treatments already employed for the treatment of effluents containing sulfates and/or metals and to evaluate the adaptability of such methodologies for AMD treatment, using MFCs. Studies indicate that the MFC technology has a very promising application in the treatment of water with high concentrations of sulfate and heavy metals. It shows great advantage over other strategies, since it does not require the addition of chemical compounds, besides generating energy, thus being self-sustainable.