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Anaerobic Biochemical Reactor (BCR) Treatment Of Mining-Influenced Water (MIW) - Investigation Of Metal Removal Efficiency and Ecotoxicity
BUTLER, B. A., M. E. Smith, D. J. REISMAN, AND J. M. LAZORCHAK. Anaerobic Biochemical Reactor (BCR) Treatment Of Mining-Influenced Water (MIW) - Investigation Of Metal Removal Efficiency and Ecotoxicity. Presented at Society for Mining, Metallurgy, and Exploration [SME], Denver, CO, February 27 - March 02, 2011.
To examine 4 active pilot BCR systems for removal of metals and toxicity.
BCR have been successful at removing a high percentage of metals from MIW, while BCR effluent toxicity has not been examined previously in the field. This study examined 4 active pilot BCR systems for removal of metals and toxicity. Removal efficiency for Al, As, Cd, Cu, Ni, Pb, and Zn was > 90%. Influent MIW samples were acutely toxic to the test organisms. Treated water was not acutely or chronically toxic in samples having BCR treatment followed by an aeration process, while samples not having aeration in the field were acutely and chronically toxic. Acute toxicity was removed [1 site] or significantly reduced [1 site] following aeration in the laboratory, most likely through removal of hydrogen sulfide produced within the BCRs. Toxicity testing methods require dissolved oxygen (DO) levels be high enough that it is not a cause of observed toxicity. Overall, results indicate that BCR treatment is effective at removing a significant proportion of metals present and that inclusion of in-field aeration as part of the passive treatment system would be beneficial for removal (or significant reduction) of acute toxicity prior to discharge of the water into a receiving stream.