The effects of ferrous iron, dissolved oxygen, and inert solids concentrations on the growth of thiobacillus ferrooxidans

The effects of suspended, inert solids concentration, ferrous iron concentration and dissolved oxygen concentration on the kinetics of iron oxidation by Thiobucillus ferrooxidans are reported. It is shown that the maximum specific growth rate for this organism, oxidizing ferrous iron, is of the order of 0.1 h −1 . Competitive inhibition by femc iron is demonstrated. The dissolved oxygen concentration below which the bacteria will not grow is 0.20 mg/L. The dissolved oxygen concentration below which O 2 availability is limiting is around 0.29‐0.7 mg/L. 10.4 millimols of CO 2 are fixed by the bacteria per mol of ferrous iron oxidized. 0.0185 mg of bacterial carbon are generated per mg of O 2 consumed. Comparative mass transfer rates for O 2 and CO 2 are discussed. Oxidation rates decreased significantly in shake flasks as suspended solids concentrations rose above 0.5%, whereas in stirred tanks solids concentrations up to 15% had little effect on oxidation rate.