Differential effects of petroleum-based and bio-based microplastics on anaerobic digestion: A review

The number of plastics is increasing owing to the rapid development of the plastics industry. Microplastics (MPs) are formed during the use of both petroleum-based plastics and newly developed bio-based plastics. These MPs are inevitably released into the environment and are enriched in wastewater treatment plant sludge. Anaerobic digestion is a popular sludge stabilization method for wastewater treatment plants. Understanding the potential impacts of different MPs on anaerobic digestion is critical. This paper provides a comprehensive review of the mechanisms of petroleumbased MPs and bio-based MPs in anaerobic digestion methane production and compares their potential effects on biochemical pathways, key enzyme activities, and microbial communities. Finally, it identifies problems that must be solved in the future, proposes the focus of future research, and predicts the future development direction of the plastics industry.

Automated summary

The number of plastics is increasing due to the rapid development of the plastics industry. Both petroleum-based plastics and bio-based plastics generate microplastics during use, which are inevitably released into the environment and accumulated in wastewater treatment plant sludge. Anaerobic digestion, a popular sludge stabilization method, is influenced by different microplastics. This paper comprehensively reviews the impact of petroleum-based microplastics and bio-based microplastics on anaerobic digestion methane production and compares their effects on biochemical pathways, key enzyme activities, and microbial communities. It also identifies future challenges, proposes research priorities, and predicts the future development direction of the plastics industry.