The basic process is based on regeneration principle. The process requires circulation of an aqueous solution to remove H2S and to regenerate the chemical taking part in the reaction. The raw biogas enters the scrubber in which a clean solvent washes the gas and removes the H2S from biogas. In addition to this, some CO2 may also get removed. The clean biogas meeting the requirement of the end application exits the absorber. The solvent, which has now become rich in sulphide due to absorption of H2S, is transferred to bio reactor. In bio reactor sulphides are oxidized to elemental sulphur by specific bacteria and used chemical is regenerated. Biological reaction generally involving oxidation by atmospheric air. The general block diagram is indicated.