Experimental study of co-digestion of food waste and tall fescue for bio-gas production

Chinese food waste (CFW) and Tall fescue (Tf) are obtainable at low cost, and the digestibility of the mixture is superior to mono-digestion. The major objective of this study was to determine optimal CFW/Tf ratio and organic loading rate (OLR) for biogas yields and organics removal rate in batch and hydraulic pressure semi continuous anaerobic treatment. Batch digestion of mixed substrates was carried out at CFW/Tf ratios of 8.89, 2.75, 1.52, 0.99 and 0.7 based on volatile solid (VS). For CFW/Tf ratio of 1.52, increasing OLR in hydraulic pressure semi continuous digester was evaluated. Results showed that positive synergistic effects of co-digestion took place at CFW/Tf ratios of 1.52 and 0.99. In semi continuous anaerobic digester, the reliability daily methane yield and effective organic matter removal was observed at OLR of 15.8 g VS/(L·d). This study showed that the co-digestion of CFW and Tf improved biogas yield and degradation efficiency. The improved characteristics indicated the co-digestion process had better stability.