Claudio Felici

A novel photobioreactor system for hydrogen sulphide biogas clean-up

Hydrogen sulphide (H2S) is a toxic and corrosive gas. Its removal from biogas is important to obtain valuable biomethane. A novel photobioreactor (PBR) has been conceived where the bacterium Chlorobium limicola converts H2S in elemental sulphur through an anoxigenic photosynthetic process. This system has proven to be stable over time. Quantitative clean-up was achieved in tests with artificial biogas with high concentration of H2S. Molecular analysis was used to check the stability of the culture under non-sterile conditions. This analysis has shown the presence of a strain belonging to Epsilonproteobacteria that does not affect the efficiency of the process. An aliquot of this bacterial culture was sampled and used as inoculum in a second experiment where the PBR was installed downstream of an anaerobic digestion plant. The efficiency of H2S removal was around 90% and the bacterial consortium remained stable. [Received: January 14, 2016; Accepted: April 24, 2016]

Bio-production of Hydrogen and Methane Through Anaerobic Digestion Stages

The anaerobic digestion (AD) is a widespread technology for the energetic valorization of organic wastes and the plants number is increasing both in industrialized and emerging countries. On the other hand, a low efficiency of the biogas production is still observed mainly due to the limited knowledge on the microorganism interactions and the lack of microbiological monitoring in the AD process. The energetic valorization of organic waste, producing both methane and hydrogen, can be increased by applying microbial ecology principles and exploiting the potential offered by functional microbial biodiversity.

A Novel Photobioreacror System for Hydrogen Sulphide Biogas Clean-Up

Hydrogen sulphide (H 2 S) 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 H 2 S is converted to elemental sulphur (S 0 )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 H 2 S. 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.