A method to produce an acid-depleted biogas is described. The method includes supplying biogas to a biogas acid removal system to produce an acid-depleted biogas. Biogas pre-processing, post-processing, and a product production system may be integrated with the biogas acid removal process to produce a product. A two-stage volatile organic compound removal process is also described including a volatile organic compound removal step, and a halogenated volatile organic compound removal step, followed by an acid removal step. Oxygen removal from the biogas is also provided by combusting oxygen together with halogenated volatile organic compounds within the biogas, followed by removing acid generated in the combustion of the halogenated volatile organic compounds.