A Review on Biodegradation of Plastics with Organic Fraction of Municipal Solid Wastes by Anaerobic Co-digestion

Abstract

Improper plastic disposal results in biological magnification since the plastics accumulated in the landfills and in the ocean find their way into the food web – getting increasingly accumulated at the top of the Ecological Pyramid. The degradation of plastic waste can be achieved by chemical, thermal, photo, and biological processes. Anaerobic co-digestion (AcoD) can be applied to biodegrade plastic waste and the organic fraction of municipal solid waste (OFMSW) while ensuring increased process stability and biogas production. While the anaerobic digestion (AD) or anaerobic mono-digestion of only plastics with high carbon content (higher carbon-to-nitrogen ratio) is challenging, the co-digestion with lower carbon-to-nitrogen ratio organic wastes results in increased biodegradation and biogas production. Pretreatment of plastic waste can surely enhance biodegradability and biogas yield, but further investigation is required to determine the economic viability of various pretreatment techniques available. This review highlights the classification of plastics based on their biodegradability, microbial species responsible for biodegradation, and the changes in the properties of plastics during biodegradation under AD and AcoD. Further, the review delves into the crucial process governing factors that affect AcoD and provides current insights for plastic biodegradation using AcoD.

Graphical Abstract