Research Progress on the Mechanism and Control Strategy of Anaerobic Digestion Imbalance of Food Waste

Mechanical biological treatment technology can be used to maximize the realization of food waste (FW) reduction, recycling, harmless management. Most of the mechanical pretreatment processes at home and abroad can be divided into four processes: transportation, sorting, crushing and three-phase separation, while the biological treatment mainly relies on anaerobic digestion technology. However, due to the differences in the environment and local management, the anaerobic digestion treatment process of FW is often inhibited by long-chain fatty acids, ammonia nitrogen, or propionic acid accumulation, which make it difficult to achieve a stable operation with high load. In this paper, the key technical issues and optimal control strategies of FW disposal were summarized and discussed. The study found that sorting and screening FW before anaerobic digestion could not only improve the resource utilization efficiency of FW, but also promote the smooth operation of the high-load anaerobic digestion system in the later stage and increase methane production. The buffering capacity of the fermentation system can be improved by adding biochar and other means to alleviate the inhibition of long-chain fatty acids and ammonia nitrogen. Therefore, it is necessary to develop smarter FW pretreatment equipment and find more efficient fermentation technology regulation methods.