Waste dump biogas (MeH content 54.19%) was purified by cooling down to -50 degrees C, removing H2O by sorption on anhydrous MgSO4 and 3-stage absorption of the Si-compds. in Me2CO. Octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane were the main impurities in the biogas according to the gas chromatog. anal. After 1st stage of absorption, over 99% of the Si compds. were removed from the biogas.