Enhanced bio-methane production by co-digestion of different organic wastes.

The paper deals with an experimental study aimed to assess the effect of mixing different organic wastes on the anaerobic digestion process. In particular, livestock manure and organic solid wastes have been taken into account as substrates, to verify if their mixing gives rise to higher methane production rates and lower risk of process failure. Bio-Methane Potential (BMP) tests have been conducted using the following substrates: buffalo manure (BM), poultry manure (PM), organic fraction of the municipal solid waste (OFMSW), greengrocery waste (GW) and two different mixtures composed of BM and OFMSW. Mixing BM with OFMSW resulted in 12 and 30% higher methane volumes after 30 and 15 days from the test start, respectively. Experimental data have been also used to calibrate and validate a mathematical model previously proposed by the authors, showing its capability to reproduce the synergistic effect on methane production promoted by co-digesting BM and OFSMW.