Unveiling the environmental gains of biodegradable plastics in the waste treatment phase: A cradle-to-crave life cycle assessment

Abstract

Biodegradable plastics have emerged as promising and sustainable solutions for addressing the environmental challenges caused by plastic wastes. In this study, we present a comprehensive cradle-to-grave life cycle assessment (LCA) of two prominent biodegradable plastics, polyhydroxybutyrate (PHB) and polylactic acid (PLA), to quantitatively evaluate their environmental impact. In cradle-to-gate analysis, production processes of biodegradable plastics from their respective raw materials were analyzed. The global warming potentials (GWPs) for 1 kg of PHB and PLA plastics were 3.09 CO2 equivalent (kg CO2 eq.) and 5.79 kg CO2 eq., respectively, which were higher than those of fossil-based plastics. However, gate-to-grave LCA demonstrated that the superior end-of-life (EOL) options for biodegradable plastics, such as anaerobic digestion and incineration, result in an overall reduction in GWP under well-controlled waste management scenarios. These findings underscore the importance of developing technology and infrastructure for the effective treatment of biodegradable plastic waste, in addition to expanding its market share. Furthermore, the comprehensive cradle-to-grave LCA provides valuable guidance for policymakers to incentivize emission reductions throughout the entire product life cycle, rather than focusing on localized scopes. We believe that the insights from this study will encourage extensive discussions on both technical and regulatory aspects, facilitating efforts towards a more sustainable plastic economy.