Sulfate reduction based bioprocesses for the treatment of acid mine drainage and the recovery of metals

Biological sulfate reduction is increasingly replacing chemical unit processes in mining biotechnology. Sulfate reducing bacteria (SRB) can be used for treating ground- and surface waters contaminated with acid mine drainage (AMD), and for recovering metals from wastewater and process streams. Biologically produced H2S precipitates metals as metal sulfides, while biogenic bicarbonate alkalinity neutralizes acidic waters. This paper reviews various passive and active SRB-based alternatives as well as some process design aspects, such as reactor types, process configurations, and choices of substrates for sulfate reduction. The latest developments of using various low-cost substrates together with new bioprocess designs are increasing the uses and applications of SRB-based bioreactors in AMD control and selective metal recovery.