The Effect of Microplastics Exposure on Anaerobic Digestion of Food Waste: A Review

Food waste (FW) is a significant renewable resource because of its high organic content and superior biodegradability. It can be effectively converted into clean energy (like methane) using anaerobic digestion technology. However, the pervasiveness of microplastics (MPs) in FW, which comes from plastic items like food packaging and throwaway tableware, not only degrades the FW's physical and chemical characteristics but also has the potential to impair the stability and effectiveness of anaerobic digestion by changing the digestion environment and microbial metabolic processes. In this paper, the occurrence characteristics and migration behavior of MPs in FW are systematically reviewed, along with the dynamic effects of the physical and chemical properties of MPs (e.g., type, particle size and concentration) on the performance of methane production, the accumulation of volatile fatty acids (VFAs), and the stability of the system during anaerobic processes. Additionally, it concentrates on examining how MPs impede activity via processes such as chemical leaching, enzyme activity interference, reactive oxygen species (ROS) induction and disruption of the microbial population. The objective of this study is to guide the effective resource exploitation of polluted organic solid waste and to theoretically support improving the tolerance of FW digestion processes to MPs stress.