Experimental analysis of inhibition phenomena management for a Solid Anaerobic Digestion Batch process

Solid Batch Anaerobic Digestion (SADB) is an interesting process that can lead to the production of quite high bio-methane from several biodegradable substrates. In particular the limited production of waste liquids discharged by the reactors, along with light pre-treatment requirement, makes this process suitable for a high spreading potential in many European regions. Unfortunately, some inhibition phenomena occur when the anaerobic digestion is performed with high Total Solids concentration, as in the SADB. These phenomena can affect negatively both the stability and the viability of the process. Among the different solution exploitable for managing these phenomena, the one based on percolate recirculation seems to be very interesting. The experimental runs conducted exploiting the Organic Fraction of Municipal Solid Waste, shows that the recirculation leads to a significant reduction of the Volatile Fatty Acids concentration along with an higher biogas production rate and stability. The biogas produced in the test with percolate recirculation is double and the VFA concentration results to be significantly lower.