Effects of anaerobic digestion of food waste on biogas production and environmental impacts: a review

Anaerobic digestion of food waste appears promising to generate biogas in the context of the growing energy demand and the circular economy. In particular, anaerobic digestion causes less air and solid waste pollution compared to incineration, gasification and pyrolysis. Actual research on biogas production using food waste focuses on the performance of substrates such as manure and bacteria, yet few investigations evaluate the impact of anaerobic digestion on the environment. Here, we review the steps of anaerobic digestion, factors that influence the process, and food waste as main and co-substrate to increase biogas yield. High metabolic activity of anaerobes is optimized by controlling temperature, pH, retention time, carbon-to-nitrogen ratio, volatile fatty acid and organic loading rate. We discuss the effect of pre-treatments such as biological, thermal, chemical and mechanical treatments, on anaerobic digestion performance. The impacts of food waste treatments on the environment are compared by life cycle analysis.