Implementation of a Sulfide-Air Fuel Cell Coupled to a Sulfate-Reducing Biocathode for Elemental Sulfur Recovery

Bio-electrochemical systems (BES) are a flexible biotechnological platform that can be employed to treat several types of wastewaters and recover valuable products concomitantly. Sulfate-rich wastewaters usually lack an electron donor; for this reason, implementing BES to treat the sulfate and the possibility of recovering the elemental sulfur (S-0) offers a solution to this kind of wastewater. This study proposes a novel BES configuration that combines bio-electrochemical sulfate reduction in a biocathode with a sulfide-air fuel cell (FC) to recover S-0. The proposed system achieved high elemental sulfur production rates (up to 386 mg S-0-S L-1 d(-1)) with 65% of the sulfate removed recovered as S-0 and a 12% lower energy consumption per kg of S-0 produced (16.50 +/- 0.19 kWh kg(-1) S-0-S) than a conventional electrochemical S-0 recovery system.

Automated summary

Bio-electrochemical systems (BES) are a versatile technological platform for treating various types of wastewaters and recovering valuable products, with the potential of high elemental sulfur production rates and lower energy consumption per kg of S-0 produced compared to conventional electrochemical recovery systems.