The important advances in the field of biological desulphurization achieved by the GENOCOV group (UAB) have allowed for the development of two specific products for the oxidation of hydrogen sulphide in biogas: biotrickling filters and bioscrubbers. The selection of one or the other technology is carried out depending on the composition of the biogas and on its use. Biotrickling filters consist of a single reactor within which specific microorganisms (Thiobacillus and others) grow. In this bioreactor the dissolution of the hydrogen sulphide and its biological oxidation to sulphate are simultaneously carried out. On the other hand, bioscrubbers comprise two reactors: In the first, a scrubber, the gaseous hydrogen sulphide is transferred to the liquid phase. This liquid phase is then transferred to a bioreactor, in which the hydrogen sulphide is oxidized to elemental sulphur. The main advantages of these processes are:

• Treatment efficiency> 99%
• Minimum consumption of chemical reagents
• Packing material durability above 15 years
• Strict control of the oxygen supply, thus eliminating the risks of explosion
• Minimal maintenance

In bioscrubbers a sulphur-containing solution with several applications in agriculture and industry is produced. Also, in these systems biogas is not diluted. Hence, biogas heat capacity does not decrease.