Anaerobic co-digestion of food waste with municipal solid waste leachate: A review and prospective application with more benefits

Anaerobic co-digestion of food waste and municipal solid waste leachate is attracting more and more attention, addressing the challenges of mono-digestion of food waste. In this paper, challenges in anaerobic digestion of food waste are briefly summarized. The synergistic effects of anaerobic co-digestion of food waste with municipal solid waste leachate are deeply discussed. Improving buffering capacity and trace metals supplementation are the two most important known benefits, while promoting refractory organics degradation and improving digestate dewaterability are firstly been raised to be two potential benefits. An innovative integrated process based on anaerobic co-digestion of food waste and leachate with nanofiltration concentrate ozonation and recirculation are developed for more benefits. Mass balance analysis of the proposed process shows that, compared with mono-digestion, the energy conversion efficiency of anaerobic co-digestion could increase by 12%-18%, with no nanofiltration concentrate generation. Furthermore, the digestate dewaterability could be improved obviously which help reduce the discharge amount of solid digestate. The process feasibility and engineering applicability are discussed, showing that anaerobic co-digestion of food waste and municipal solid waste leachate is applicable, especially in megacities.