Methane production from anaerobic co-digestion of sewage sludge and decanter cake

Increased production of sewage sludge from wastewater treatment and decanter cake from palm oil mill industry results in the generation of large quantities of waste that ends up difficulty to find the effective method of disposal. In this study, an anaerobic co-digestion has been considered to convert these organic pollutants into methane gas. Anaerobic co-digestion of sewage sludge and decanter cake was studied in 125mL serum bottles with 100mL working volume. The effect of different inoculum to substrate ratios (I/S) on biogas production was investigated. The batch study was conducted at the ratio I/S of 1:0.5, ratio 1:1 and ratio 1:2 and sewage sludge alone as control at ratio 1:0. Daily biogas collection for the ratio of 1:2 had resulted the highest cumulative biogas production of 247 mL. The highest methane yield was obtained at mixing ratio of 1:0.5 with 165.6 L CH4 / g VS. As a comparison, all co-digestion ratios produced more biogas than the sewage sludge alone. This proved that anaerobic co-digestion of sewage sludge and decanter cake can improve the production of biogas