NOVELTY - The method for processing of biogas (1) for supplying into natural gas network of the quality level of low-gas (L-gas), comprises removing impurities such as ammonia, hydrogen sulfide, sulfur dioxide and organic sulfur compounds from the biogas impurities, completely separating carbon dioxide (5) contained in the biogas, splitting air into oxygen and nitrogen (95 vol.%) by change in pressure adsorption, compressing the nitrogen and then admixing to highly pure methane (2) for reducing heat output and dehumidifying the formed methane/nitrogen mixture (L-gas).    USE - The method for processing of biogas for supplying into natural gas network of the quality level of low-gas (L-gas).    ADVANTAGE - The method ensures simple, safe and economical processing of biogas and enables complete removal of carbon dioxide from the biogas.    DETAILED DESCRIPTION - The method for processing of biogas (1) for supplying into natural gas network of the quality level of low-gas (L-gas), comprises removing impurities such as ammonia, hydrogen sulfide, sulfur dioxide and organic sulfur compounds from the biogas, completely separating carbon dioxide (5) contained in the biogas, splitting air into oxygen and nitrogen (95 vol.%) by change in pressure adsorption, compressing the nitrogen and then admixing to highly pure methane (2) for reducing heat output in metered manner, and dehumidifying the formed methane/nitrogen gas mixture (L-gas). The methane and nitrogen are combined by a static mixing process. The water/methane/nitrogen mixture resulting from dehumidifying process is separated by condensation of the gas mixture (3) and then led back into the biogas flow and the water is led back into the wash process. The nitrogen of 10-35 m3/m3 of the methane is added for the reduction of the heat output of the methane to 1 kWh/m3. The metered quantity is measured on nitrogen as a function of the carbon dioxide content of the methane. The separation of carbon dioxide from the biogas takes place by an amine wash on a carbon dioxide content of below 2 vol.%. The produced oxygen for the biocatalytic desulfurization of biogas is introduced into a fermenter of a biogas plant or a separate desulfurization plant. The carbon dioxide and sulfur from the biogas are separated by a wash with an amine containing washing solution (6) under normal pressure and standard temperature. An INDEPENDENT CLAIM is included for a plant for the processing of biogas.    DESCRIPTION OF DRAWING(S) - The diagram shows a plant for the processing of biogas (Drawing includes non-English language text).    Biogas (1)    Methane (2)    Gas mixture (3)    Carbon dioxide (5)    Washing solution. (6)