Nickel-Loaded Shrimp Shell Biochar Enhances Anaerobic Digestion of Food Waste

This investigation evaluated the effectiveness of shrimp shell biochar (SBC) and SBC absorbed with Ni2+ in promoting the activity of microorganisms during anaerobic digestion of food waste. The results showed that the methane yield of the control (without SBC), SBC, SBC with low concentration Ni2+, and SBC with high concentration Ni2+ were 81.8, 116.1, 134.7, and 99.2 mL/(g·VS), respectively. SBC could promoted the activity of microorganisms, and Ni2+ adsorbed on SBC was released into the digestive fluid during the process. The effect of Ni2+ on anaerobic digestion of methane production accorded with the Hormesis effect of “Low Promotion and High Inhibition”. The most important methanogen was Methanosaeta. SBC could help Methanosarcina proliferation, and low concentration Ni2+ could promote the number and activity of Methanosarcina and Methanobacterium. The results show that biochar loaded with trace elements such as nickel can be used in anaerobic digestion technology