POTENTIAL OF THIOBACILLUS-FERROOXIDANS FOR WASTE-GAS PURIFICATION .1. KINETICS OF CONTINUOUS FERROUS IRON OXIDATION

Kinetic data of ferrous iron oxidation by Thiobacillus ferrooxidans were determined. The aim was to remove H2S (<0.5 ppm) from waste gas by a process proposed earlier. Kinetic data necessary for in scale-up were investigated in a chemostat airlift reactor (dilution rate 0.02-0.12 h(-1); pH 1.3). Due to the low pH, ferric iron precipitation and wall growth could be avoided. The maximum ferrous iron oxidation rate of submersed bacteria was 0.77 g l(-1) h(-1), the maximum specific growth rate about 0.12 h(-1) and the yield coefficient was found to be 0.007 g g(-1) Fe2+. The specific O-2 demand of an exponentially growing, iron-oxidizing batch culture was 1.33 mg O-2 mg(-1) biomass h(-1). The results indicate that a pH of 1.3 has no negative influence on the kinetics of iron oxidation and growth.