Selection of low environmental risk processes in plastic waste recovery by comparative life cycle assessment

This study investigates the environmental impact of different valorization methods for solid and liquid products obtained from thermochemical recycling of high‐density polyethylene (HDPE) plastic waste and the mechanical recycling of these wastes. In this context, the mechanical recycling of HDPE plastic waste to produce granular raw materials (MechRecyc) and the chemical recycling of HDPE plastic waste to produce epoxy composite materials from pyrolysis chars (Pyro‐Epoxy) were discussed. Comparative life cycle analyses were conducted using SimaPro software, considering midpoint and endpoint categories for all three processes. MechRecyc performed best in terms of impact categories describing global warming, human toxicity and ecotoxicity, and fossil resource depletion. Pyro‐Fuel had the most positive impact in terms of pollutant discharges and clean water consumption. Considering all environmental impact categories, mechanical recycling had the most positive environmental impact, while both pyrolysis‐based recycling methods were found to have very similar impacts.