Investigating the biodesulfurization potential of isolated microbial consortia: Impact of sulfide loading, pH and oxidation-reduction potential on sulfur recovery

Acid rain is regarded as one of the major concerns due to the release of sulfur-containing wastewaters from petrochemical and other allied industries. Biological desulfurization, an ecofriendly process offers no secondary pollution and allows for the recovery of elemental sulfur as a valuable product in a useable form as fertilizer and can be used as raw material in various industries. Therefore, this work explores the bio desulfurization potential of mixed microbial consortia that was isolated from various sources for the removal of sulfur containing compounds from synthetic wastewater at varying influent sulfide loading rate. Further, this study focused on optimizing the critical process parameters such as influent sulfide loading rate, ORP and pH to achieve maximum sulfur recovery. The experiments were performed at varying sulfide loading of 3000, 4000, 5000 and 6000 mg/L using the isolated mixed consortia at an ORP of −300 ± 20 mV and −360 ± 20 mV for an incubation period of 70 h. Results revealed that the isolated microbial consortia belong to the genera 73% Pseudomonas, 24% Alishewanella and 3% Zobellella. The maximum sulfide conversion efficiency to sulfite 309 mg/L, elemental sulfur 1152 mg/L and sulfate 1813 mg/L was exhibited by microbial consortia at an initial sulfide load of 6000 mg/L and ORP of −360 ± 20 mV.