Effect of operation conditions on biological Fe(II) oxidation with rotating biological contactors

The feasibility of treating acid mine drainage by a rotating biological contactor system, seeded with acidophilic iron-oxidizing bacteria to oxidize ferrous iron to the ferric form, which could then be removed by precipitation with inexpensive calcium carbonate, was investigated in the laboratory. The effects of iron concentration, pH, temperature, and rate of disc rotation on the efficiency of the process, were investigated. The rate of oxidation was first-order with respect to ferrous-iron concentrations up to 150 mg per litre. The rate of oxidation was not affected by pH in the range 1.0-2.6 or by temperature in the range 10-40C, but increased with increase in the peripheral velocity of the discs from 4.7-28.2 m per minute.