Anaerobic digestion is very important in Hungary to handle agricultural waste streams. The diversity of the feed stream of biogas production can affect on reactions and the fermenter can produce such byproducts as hydrogen sulfide. Most of these systems produces biogas for power generation. H2S separation is good to save the biogas motor against reduced lifetime. In our work we use competitive chemisorption for selective separation of the sulphur content of the gas stream but CO2 to be left. By using this type of separation, we can save reagent and our technology can lower wastewater production.