Study on Synergistic Anaerobic Digestion of Peanut Meal and Food Waste

Conventional treatment methods for food waste are often resource-intensive and inefficient. For this problem, we explore the feasibility and synergistic mechanisms of co-anaerobic digestion of food waste and peanut meal. Therefor, batch digestion experiments were conducted for 30 days at 35 ℃ with food waste and peanut meal mixed at ratios of 8∶2, 7∶3, 1∶1, 3∶7, and 2∶8 (based on volatile suspended solid), and mono-digestion of each substrate is served as control. The results showed that the addition of peanut meal effectively adjusted the carbon to nitrogen ratio of system. At a mixing ratio of 7∶3, the methane production was increased by up to 22.43%, reaching 193.96 mL/g. Moreover, co-digestion increased the concentration of short-chain fatty acids (SCFAs). The concentration of SCFAs was 4 148.31 mg/L, representing an increase of 57.11% comparing to that of the mono-digestion. Co-digestion enhanced both the total output and the composition profile of SCFAs. This process also avoided system instability caused by excessive acidification, thereby providing a more continuous and stable substrate supply for the methanogenic phase. The relative abundance of the methanogenic archae of Candidatus Methanofastidiosum in the co-digestion system increased by 4.86%, facilitating the optimization of hydrogen metabolism process. This study demonstrates that co-digestion of food waste and peanut meal enhances anaerobic digestion performance, offering a viable pathway for the synergistic and efficient resource recovery of both substrates.