Published on May 2021 | Applied Science

Effect of Biochar from Banana Peel on the Stability of Methane Production from Food Waste at Different Organic Loading Rates

Anaerobic digestion is widely regarded as a suitable technology for food wastes treatment along with methane production. However, high biodegradability of food wastes usually leads to the rapid accumulation of volatile fatty acids (VFAs), which causes the instability of the anaerobic digestion process. The addition of biochar is one of the methods to improve the stability of anaerobic digestion. In this study, biochar from banana peel was used as an additive to stabilize anaerobic digestion of food waste at different organic loading rates (OLR) in reactors with a working volume of 5 L. The food waste mixed with 20 g/L of banana peel biochar was fed into the reactor with different OLRs of 1 to 6 g-VS/L-reactor.d. Another reactor at the same operating conditions without the biochar was set as a control. Results showed that the addition of banana peel biochar improved the stability of anaerobic digestion. The reactor with biochar could operate at the maximum OLR of 5 g-VS/L-reactor.d with the highest methane production rate of 888 mL/L-reactor.d and 80.77% removal of chemical oxygen demand. Moreover, biochar revealed effective color adsorption from the effluent of anaerobic digestion. However, instability of the control reactor was observed at the OLR higher than 2 g-VS/L-reactor.d. Thus, the control reactor had failed to operate due to the rapid drop of pH. Therefore, the addition of biochar from banana peel into the anaerobic digestion of food waste enhanced the process stability, the methane production, and the quality of effluent.