Performance of Field-Bioreactors with Sulfate-Reducing Bacteria to Control Acid Mine Drainage

Three Sulfate-Reducing Bacteria (SRB) passive field-bioreactors were constructed at an abandoned mine site near Butte, Montana, to mitigate AMD emanating from a waste rock pile. Each SRB field-bioreactor contains chambers of an organic source, limestone, and cobbles. The field-bioreactors are configured differently to test the effect of different environmental conditions on the SRB. Preliminary observations indicate that, during start up and the first eight months of operation, the quantity of organic carbon supply significantly impacts the SRB activity. To date, the dissolved metals have been reduced significantly and the pH has increased.