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Photobioreactor for biogas clean-up

AgricolturaAgricultureBiological clean-upLEDLEDs


The patent concerns a photobioreactor, illuminated by specific LEDs, in which a solution containing a liquid culture medium and a population of photo-synthetic sulphoxidizing bacteria that transform the sulphidic acid into elemental sulfur is made to flow. The bacterial cultures used are very resistant, easy to manage and do not require dangerous and / or expensive reagents. Bio-sulfur presents possibilities of use in the agronomic sector.

Technical features

The patent concerns a system for hydrogen sulphide removal from biogas, a highly toxic and corrosive compound which can damage pipelines and engines. The proposed process is based on a photobioreactor illuminated by specific LEDs in which a culture of green sulphur bacteria is recirculated to convert hydrogen sulphide into sulphur. A settling section allows to extract the elemental sulphur. The insertion of the system downstream of an anaerobic digestion plant of organic waste, in addition to performing the necessary biogas desulphurization function, allows a total recycling of sulphur making the whole process eco-compatible. By eliminating the use of reagents and the formation of potentially toxic products, the system allows to limit the management costs for desulphurisation. The high environmental sustainability is due to the recycling of sulpur obtained from the conversion of hydrogen sulphide into bio-sulfur which represents a product with different commercial uses in the industrial and agricultural sectors.

Possible Applications

  • Anaerobic digestion plants for of biogas / biomethane production;
  • Possible application in wastewater treatment;
  • Commercial exploitation of bio-sulfur as a phytosanitary and / or soil conditioner in agriculture.


  • Sulfur recycling;
  • cost reduction;
  • elimination of dangerous and / or expensive reagents;
  • possible modularity.