Effect of organic loading rate during anaerobic digestion of municipal solid waste

• Co-digestion of OFMSW with inoculum: an effective approach in methane production.
• COD removal affects methane production rate with respect to different pH.
• Maximum COD removal of 84.20% achieved with a CH4 production of 9.22 L.
• Multiple regression analysis proved COD removal efficiency over CH4 production.

The effect of chemical oxygen demand (COD) and volatile solids (VS) on subsequent methane (CH4) production during anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW) was studied in a laboratory-scale digester. The experiment was performed in 2 L anaerobic digester under different experimental conditions using different input mass co-digested with inoculum and organic loading rate (OLR) for 27 days at 38 ± 2 °C. Three digesters (digesters 1, 2 and 3) were operated at initial loading of 5.1, 10.4 and 15.2 g/L CODS per batch which were reduced to 77.9% and 84.2%, respectively. Cumulative biogas productions were 9.3, 10.7 and 17.7 L in which CH4 yields were 84.3, 101.0 and 168.4 mL/g VS removal in digesters 1, 2, and 3, respectively. The observed COD removal was found to be influenced on variation in CH4 production. Co-efficient of determination (R2) was 0.67 and 0.74 in digesters 1 and 2, respectively.