Bioplastic Wastes: The Best Final Disposition for Energy Saving

The pressing need to reduce the consumption of non-renewable resources and the emission of greenhouse gases into the environment, in recent decades has led to the wide development of bio-based plastics that are produced from renewable sources, such as corn, wheat, oil seeds etc. Actually, the most important bio-based plastics on the market are the poly(lactic acid) (PLA) produced from Nature Works (USA) and the Mater-Bi, a starch based bioplastics, made from Novamont (Italy). The aim of this work is not only to assess the actual energy and greenhouse gases (GHGs) savings resulting from the production of bioplastics, compared with the production of conventional plastics, but also to analyze what might be the best final disposition of bioplastic wastes in order to maximize the energy saving. Therefore, by using the Life Cycle Assessment (LCA) methodology, LCAs cradle to gate and cradle to grave were carried out both for PLA and Mater-Bi, taking into consideration as final scenarios composting, incineration, anaerobic digestion and mechanical recycling processes. The work demonstrates how incineration, composting and anaerobic digestion processes are clearly under-performing, from an environmental point of view, with respect to the mechanical recycling process.