A Kinetic Analysis of Microbial Sulfate Reduction in an Upflow Packed-Bed Anaerobic Bioreactor

The effects of initial sulfate concentration on anaerobic sulfate reduction and sulfide generation kinetics were investigated in an up-flow bioreactor, using a consortium of sulfate-reducing bacteria (SRB) from water produced from a Brazilian oil reservoir. Redox potential and sulfate concentration were measured to indicate the growth and activity of the SRB throughout the experimental runs. The results of the batch regime indicate that sulfate conversion and sulfide generation are both first-order processes for initial sulfate concentrations of 1,000 and 3,500 mg/L. The kinetic constants for the sulfate conversion indicate that the enhanced initial sulfate content was initially inhibiting, but that the sulfide generation reaction is almost independent of the initial sulfate concentration, likely due to the presence of at least two in-series processes that are faster than the microbial conversion of the sulfate.