IMPROVEMENT OF THE BIOCHEMICAL METHANE POTENTIAL OF FOOD WASTE BY MEANS OF ANAEROBIC CO-DIGESTION WITH SWINE MANURE

ABSTRACT Food waste (FW) has potential for use by means of anaerobic digestion (AD). However, some characteristics of FW affect process stability and methane (CH4) production. Using biochemical methane potential (BMP) tests, this study assessed the improvement of CH4 production and hydrolysis of FW by means of anaerobic co-digestion (AcoD) with swine manure (SM). Different FW:SM ratios were studied under conditions with (WN) and without (NN) nutrients. The highest CH4 production was obtained for the FW:SM 60:40 ratio in the WN and SN conditions with values of 72.87 and 62.83 mL CH4 g VS-1, respectively. This showed that AcoD of FW with SM presented synergistic effects, since increases of 27 (WN) and 13% (NN) were obtained in comparison with the mono-digestion of FW. There was also an improvement in the process stability (α index > 0.7), but there were no favorable effects with respect to the hydrolysis of FW.