Nickel-loaded shrimp shell biochar enhances batch anaerobic digestion of food waste. (May 2022) - Li, Xiao
Graphical abstract: Highlights: The addition of SBC increased intensity of all bio-processes in anaerobic digestion. The promoting effect of low load Ni was mainly concentrated in methanogenesis. The influences of loaded-Ni accorded with "Low Promotion and High Inhibition". SBC could help Methanosarcina proliferation. Low concentrations of Ni could promote the number of Methanosarcina and Methanosaeta . Abstract: This study evaluated the effectiveness of shrimp shell biochar (SBC) and nickel (Ni) loaded SBC in increasing methane yield during anaerobic digestion of food waste. The results indicated that the methane yields of control (without SBC), SBC, SBC loaded with the low concentration of Ni, and SBC loaded with the high concentration of Ni were 81.8, 116.1, 134.7, and 99.2 mL/(g·VS), respectively. SBC promoted the efficiency and stability of the whole anaerobic digestion process including hydrolysis, volatile fatty acid conversion and methanogenesis. While the invigorating effect of loaded Ni at the low concentration of 0.88 mg/g was mainly concentrated in methanogenesis, the inhibition effect of the high Ni concentration was comprehensive. SBC helped Methanosarcina proliferation, and low concentration Ni promoted the number and activity of Methanosarcina and Methanosaeta . The results show that biochar loaded with a low level of trace elements such as Ni can promote the anaerobic digestion process.