Effect of nickel-containing activated carbon on food waste anaerobic digestion

Anaerobic digestion (AD) is frequently restricted with the long lag phase and low methane (CH4) production rate. Laboratory batch experiments were conducted to investigate the impact of different supplements on the performance of food waste AD, including AC-Ni, AC, and Ni. Results showed that the lag phase of AD was reduced with the addition of those supplementations. Compared with the control group without any supplementation, the AC-Ni could shorten the lag phase by 67% and increase the maximum CH4 production rate by 50%, respectively. The speciation analysis indicated that the environmental risks of the AC-Ni was reduced by 30% after digestion. Microbial community structure analysis revealed that the AC-Ni promoted the evolution and activity of the hydrolytic-fermentative bacteria (e.g. Firmicutes and Bacteroidetes) and methanogens (e.g. Methanobacterium, Methanoregula and Methanomassiliicoccus). This study suggested that the AC-Ni waste could be feasible to be applied to enhance the performance of AD.