Anaerobic co-digestion of food waste, goat and chicken manure for sustainable biogas production

Abstract

Anaerobic digestion of food waste alone is not very stable due to its acidic nature and high biodegradability. Co-digestion of food waste with alkaline substrate such as chicken manure and goat manure could enhance process stability and biogas yield. In this study comparison of mono digestion of food waste with 8% total solid content at an ambient temperature and co-digestion of food waste, goat and chicken manure at ratio 5:2:3 and 2:1:1 with 8% total solid content at an ambient temperature in hilly region of Nepal were carried out. Biogas yield was highest with mixing ratio of 5:2:3 with the values of 109 ml/gVS followed by mixing ratio of 2:1:1 with the values of 80 ml/gVS. Mono digestion of food waste was not stable and broke down after two weeks of operation. Findings from this study suggests that co-digestion could be a suitable method for addressing the problem related to stability in a single substrate digestion in an ambient temperature condition. Moreover, mixing ratio of co-digestion substrates is important for improved biogas production. Co-digestion of food waste with goat and chicken manure could be a practical approach for sustainable clean energy production and waste management in context of Nepal.