Remediation of acid mine drainage by sulfate reducing bacteria in biofilm reactors

Acid mine drainage (AMD) is an environmental hazard in many parts of the world. Processes using sulfate reducing bacteria (SRB) have proven to be successful in the treatment of metal contaminated water. Known SRB strains, however, are sensitive to the low pH of AMD. Therefore, we have isolated acidophilic/acidotolerant SRB strains from acidic sites and begun to study their potential for use in AMD remediation. In order to develop a simple and robust low-cost system for treatment of AMD, a biofilm reactor system was constructed. Three different SRB consortia were tested (various combinations of acidophilic and neutrophilic SRB) and three carbon and energy sources (lactic acid, glycerol and ethanol) were evaluated for their potential use. All three SRB-consortia reduced sulfate when challenged with acidic influent, at rates of about 0.3 g SO42-/l*day.