The present disclosure relates to a biogas purification system and method for removal of sulfur and halogenated compounds and acidic reaction products from biogas. A contaminant removal module is supplied containing a catalytic oxidation catalyst comprising vanadium oxide (V.sub.2O.sub.5) on a metal oxide support where the catalyst oxidizes 85% or more of the sulfur and halogenated compounds. This may be followed by a contaminant removal module containing alkali impregnated carbon which removes 85% or more of the acidic reaction products. If siloxane impurities are present in the biogas, one may utilize a contaminant removal module containing alumina oxide.
Francis Y. Huang