As wastewater treatment facilities continue to push towards greater energy savings, there is continued focus on pursuing additional steps for energy recovery. Nowhere in the solids treatment process is this more attainable than anaerobic digestion. Biogas produced from the biological decomposition of organic solids through anaerobic digestion is an energy rich source that contains up to 70% methane, which can be recovered and utilized as a potential revenue stream for the plant. In order to accomplish this, various treatment steps are needed to turn biogas into fuel. Untreated biogas is saturated and composed of methane, CO2, and trace amounts of nitrogen and hydrogen sulfide. It also will likely have several different species of siloxane. Siloxane is a common additive to everyday household items. When combusted, siloxane in the biogas is converted to silicon dioxide or sand. This build-up reduces efficiency and increases operating cost for most biogas utilization equipment. The focus of the paper is to discuss the various types of technologies to treat and improve biogas quality. The main constituents of biogas that must be removed are water, H2S, siloxane, and particulate matter.