A Novel Photobioreacror System for Hydrogen Sulphide Biogas Clean-Up

Abstract

Hydrogen sulphide (H₂S) is highly toxic and corrosive, thus biogas clean-up represents an important issue to be overcome in order to obtain valuable biomethane. A novel photobioreactor (PBR) design based on the anoxigenic photosynthesis process through H₂S is converted to elemental sulphur (S⁰)by the action of Chlorobium limicola was tested. The system has been proven stable for long lasting experimental time. The total clean-up was reached providing artificial biogas mixture with high concentration of H₂S. Molecular analysis was used to investigate whether the stability of the culture under non-sterile conditions. At the end of the experiment a strain belonging to Epsilonproteobacteriaceae was found in the culture that doesn’t affect the process. An aliquot of bacterial culture was collected and used as inoculum for a second configuration where the PBR has been installed downstream of an anaerobic digestion plant. Total clean-up was reached with some oscillation around 90%. The bacterial consortium remain stable during the experimental time.