Enhancement of Thermophilic Digestion of Food Waste (FW) via Trace Element Supplementation

In this study, the role of trace element (TE) supplementation and performance characteristics of a thermophilic anaerobic digester fed by food wastes (FW) is investigated in the long run, and a representative operational data set for field application is reported over the whole experimental period. Continuous feeding of food wastes with a dry matter of 5% for 150 days was carried out using a 100 L pilot-scale CSTR type anaerobic digester under thermophilic operation conditions. Hydraulic retention time (HRT) and organic loading rate (OLR) were kept around 28 days and less than 3.0 kg oDM m day, respectively. Volumetric biogas production values were reported to be 0.32 m m day during the period where there is no TE supplementation; on the other hand, biogas production was doubled (0.69 mmday) following TE supplementation. This corresponds to an average unit biogas production of 317 and 443 L kg oDM, during TE supplementation and no TE supplementation periods, respectively. Statistical analysis indicated that Co, As, Se, and Al were the most significant trace elements affecting the digester performance.