Removal of H2S in waste gases by an activated carbon bioreactor

A type of bioreactor packed with granular activated carbon (GAC) as support material was used for the removal of high concentrations of H2S in waste gases. Experiments about the physical adsorption capacity of GAC matrix, retention time and pressure drop were carried out; the abilities of bioreactor to buffer shock loading and removal efficiency (RE) of long-term operation were also investigated. Besides, the kinetics analysis of single-stage biodesulfuration was also studied. The results showed that GAC matrix provided high bacteria adsorption capacity, showed a superior resistance to shock loading and allowed good operational control in area of pressure drop. When the retention time was 25 s and influent concentration of H2S was 100 mg L−1, the REs were beyond 98%. An average 96.8% RE was achieved during the long-term operation for GAC bioreactor under different concentrations up to 120 mg L−1 by keeping constant flow rate. No acidification was observed in the GAC bioreactor during the long-term operation. The kinetic analysis showed that the maximum removal rate and the saturation constant in the GAC bioreactor were 666.7 mg(H2S) (L d)−1 and 20.8 mg L−1, respectively. The response of bioreactor to shock loading operation showed that GAC bioreactor has gotten a good buffering capacity to withstand fluctuating loading conditions.