the experimental and theoretical studies conducted on the possible effects of oxygen in
biogas generating anaerobic digesters. The interactions of oxygen with various biochemical processes associated with
anaerobic digestion are discussed together with other relevant aspects. The conventional perception of oxygen being
merely toxic in anaerobic digestion (AD) is refuted. Digesters can withstand significant levels of oxygenation without
drastic negative impacts. Limited quantities of oxygen can even lead to improved AD reactor performance under certain
operating conditions. Co-existence of anaerobic and aerobic cultures in a single bioreactor environment has been
demonstrated. It is shown that the partial aeration assisted AD can serve as a beneficial treatment strategy for
simultaneous waste treatment and energy generation, for a multitude of organic waste categories.