Water Sci. Technol.

An up-flow inner-cycle anoxic bioreactor with a novel three phase separator was designed and implemented for the treatment of sulfide wastewater. The sulfide in wastewater could be converted to elemental sulfur by sulfide oxidizing bacteria, and recovered by simple precipitation. When the oxidation-reduction potential (ORP) was controlled at -100 mV, 91.3% of sulfide could be oxidized to elemental sulfur. To achieve high removal percentage of sulfide and conversion percentage of sulfur, the pH of influent should be controlled in the range from 7.0 to 8.0. The optimal desulfurization process was carried out at 400 mmol L-1 d(-1) sulfide loading rate and 120 min hydraulic retention time (HRT). The removal percentage of sulfide was approximately 95.2% and elemental sulfur conversion percentage was above 90.3%. These results demonstrated that the novel up-flow in-cycle bioreactor had a potential value for the enhanced treatment of sulfide wastewater from biogas purification.An up-flow inner-cycle anoxic bioreactor with a novel three phase separator was designed and implemented for the treatment of sulfide wastewater. The sulfide in wastewater could be converted to elemental sulfur by sulfide oxidizing bacteria, and recovered by simple precipitation. When the oxidation-reduction potential (ORP) was controlled at -100 mV, 91.3% of sulfide could be oxidized to elemental sulfur. To achieve high removal percentage of sulfide and conversion percentage of sulfur, the pH of influent should be controlled in the range from 7.0 to 8.0. The optimal desulfurization process was carried out at 400 mmol L-1 d(-1) sulfide loading rate and 120 min hydraulic retention time (HRT). The removal percentage of sulfide was approximately 95.2% and elemental sulfur conversion percentage was above 90.3%. These results demonstrated that the novel up-flow in-cycle bioreactor had a potential value for the enhanced treatment of sulfide wastewater from biogas purification