Assessing the anaerobic degradability and the potential recovery of biomethane from different biodegradable bioplastics in a full-scale approach

The aim of the present study was to evaluate the anaerobic degradability and the potential recovery of biomethane from different bioplastics using a full-scale approach. Bioplastics were placed inside a real anaerobic digestion plant working under thermophilic conditions and quantitative and qualitative degradation of bioplastics was evaluated. Laboratory-scale experiments were used to determine the amount of biomethane produced by anaerobic degradation of bioplastics. Polylactic acid-based items may degrade completely using retention times compatible with anaerobic digestion plants contributing positively to biomethane production, i.e., in 90 days 397 +/- 8 NL CH4 kgvolatile solids produced by polylactic acid-based cutlery. Starch-based shoppers showed a quick degradation of the starch component in the first month of anaerobic digestion, followed by a slow degradation of the polyester component. Anaerobic digestion and/or anaerobic digestion coupled to digestate composting may represent the best strategy to dispose these wastes meeting the principles of Circular Economy.

Automated summary

The aim of this study was to evaluate the anaerobic degradability and potential recovery of biomethane from different bioplastics. The results showed that certain polylactic acid-based items can degrade completely and contribute positively to biomethane production. Starch-based items showed a faster degradation of the starch component compared to the polyester component. Anaerobic digestion and/or anaerobic digestion coupled to digestate composting may be the best strategy for disposing of these wastes while meeting the principles of Circular Economy.