Kinetic studies on anaerobic reduction of sulphate

The effects of sulphate concentration and its volumetric loading on the activity of anaerobic sulphate reducers and the kinetics of sulphate reduction were investigated using continuous bioreactors at a temperature of 35 degrees C and a pH of 7.5. Media containing different concentrations of sulphate in the range of 1 to 5 kgm(-3) were tested. For each medium the kinetics of sulphate reduction at different volumetric loading (dilution rates) were determined. With media containing 1, 2.5 and 5 kgm(-3) of sulphate, maximum conversions of 85%, 91% and 93% were achieved respectively at a retention time of 10 days. The increasing of initial concentration of sulphate resulted in higher reduction rates, with a maximum of 0.075 kgm(-3)h(-1) observed with medium containing 5 kgm(-3) of sulphate. The corresponding conversion of sulphate was 54% at a retention time of 1.5 days. Kinetics of microbial growth was also influenced by initial concentration of sulphate, with an increasing trend in both values of mu(m) and K-s due to an increase in initial concentration of sulphate.