NOVELTY - The method comprises separating components such as carbon dioxide, sulfur components, ammonia and other water-soluble materials, from biogas into a multi-stage cleaning process. The cleaning process is carried out in three cleaning steps directly following one after the other under use of free fresh water guided in circulation. The biogas to be cleaned taken away from a biogas plant is flowed through as first cleaning step under normal pressure or at over pressure of up to 6 bar to wash column with packing fill in counter current to feed fresh water.    USE - Method for cleaning of biogas for obtaining methane.    ADVANTAGE - The method ensures simple and efficient cleaning of biogas thus ensuring obtaining of methane with high quality and quantity.    DETAILED DESCRIPTION - The method comprises separating components such as carbon dioxide, sulfur components, ammonia and other water-soluble materials, from biogas into a multi-stage cleaning process. The cleaning process is carried out in three cleaning steps directly following one after the other under use of free fresh water guided in circulation. The biogas to be cleaned taken away from a biogas plant is flowed through as first cleaning step under normal pressure or at over pressure of up to 6 bar to wash column with packing fill in counter current to feed fresh water and the carbon dioxide, sulfur compound, ammonia and other organic water soluble material contained in the raw biogas are bound in the fresh water. The methane gas is drawn-off at the head of the wash column with a methane content of 65%. The almost completely dissolved (90%) methane is separated from the wash water led away from washing step in a first stripping column with packing fill or packaging under supply of stripping air and oxygen in a quantity of 0.5-10% related to the quantity of the biogas to be supplied under normal pressure in counter current principle at up to 60 degrees C in wash water and consists of oxygen containing stripping gas in fuel gas quality. The dissolved carbon dioxide is separated up to a remaining content of less than 200 mg/l from the cleaned wash water led away from the first stripping column in a second stripping column with packing fill or packaging under supply of stripping air in a quantity of 25% related to the quantity of biogas to be supplied under normal pressure in the counter current principle in the wash waster. The fresh water led in the circulation has a temperature of 65 degrees C. The stripping gas from the first stripping column is led back in the fermenter of the biogas plant or the methane gas stream separated from the first wash stage is led or utilized as fuel gas. The first stripping column is led for separating of methane from the wash water to be cleaned. The oxygen in the first step and stripping air in the second step are led in reversed sequence and two different fuel gases are received with different oxygen content. The oxygen rich fuel gas is used as oxygen source for a biological desulfurization of the biogas. The methane gas drawn-off in the wash column is brought single or together with the stripping gas to further processing for increasing the methane content. The biogas to be supplied is adjusted before the introduction into the wash step to a sulfur content of less than 5 ppm. The wash water is partially or completely transferred through fresh water after a certain processing duration during enriching of the sulfur content in the wash water over 50 ppm. The partial quantity of the wash water drawn-off at the sump of the second stripping column circulates and reaction agent binding hydrogen sulfide is used and the wash water after filling the sulfate-sulfide is led back in the circulation. The wash quantity and/or the wash water temperature is adjustable in the wash column of the separation power for carbon dioxide dissolved in the wash water. A high wash water quantity and a deep wash water temperature guide to a high separation power. The cleaned biogas drawn-off from the wash column is introduced for increasing the methane concentration and the storage capacity of the biogas in the fermenter directly in the fermenter of the biogas plant. An INDEPENDENT CLAIM is included for a plant for cleaning of biogas for obtaining methane.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a plant for cleaning of biogas for obtaining methane (Drawing includes non-English language text).    Circulation line (01, 02, 03 04, 05, 06, 09, 10)    Spillways. (11)