A dynamic simulation of a two-phase anaerobic digestion system for solid wastes

In this article, a two-phase system for the digestion of wastes with a high solid content is simulated. The solids are charged to the hydrolyzer and then leachate recirculation is activated until biodegradation is nearly complete. Several parameters are tested, namely moisture, leachate recirculation flow rate, and hydrolyzer-methanizer volume ratio. The results show that recirculation rate is an important parameter subject to optimization, with optimal values corresponding to hydrolyzer hydraulic retention times below 1 day. The quantity of recirculating water must be the highest possible. As a consequence, the organic load to the methanizer is reduced, making thus possible the use of a smaller methanizer volume.