Life cycle analysis of mechanical recycling vs. conventional incineration for brominated acrylonitrile butadiene styrene (ABS) derived from WEEE

Abstract

This study provides the first comprehensive life cycle assessment (LCA) comparing pre-mechanical recycling methods for acrylonitrile butadiene styrene (ABS) from waste electrical and electronic equipment (WEEE) containing restricted brominated flame retardants (BFRs). By evaluating the environmental impacts of BFR extraction techniques, this research addresses a critical gap in prior studies that predominantly focused on extraction efficiency. This research identifies BFR removal, required for compliance with EU Regulation 2019/1021, as the most environmentally impactful stage of the recycling process. While ABS recycling was found to offset 60–100 % of environmental impacts compared to virgin production, particularly in resource consumption and global warming, energy consumption emerged as a key factor influencing environmental performance across most extraction methods. Among the techniques analyzed, Soxhlet extraction exhibited the lowest environmental impact, followed by supercritical CO₂ and flask-shake solvent extractions. In contrast, the dissolution-precipitation method demonstrated a significantly higher environmental footprint due to its reliance on organic solvents, which contribute 80–90 % of impact categories such as greenhouse gases (GHG) emissions (19.69 kg CO₂ eq.) despite the high solvent recycling efficiency of 80 %. The findings also revealed that mechanical recycling, when combined with extraction techniques, is more environmentally favorable than incineration in terms of abiotic resource depletion. Nonetheless, incineration remains the most viable option when considering overall environmental performance metrics. This study underscores the urgent need for BFR extraction optimization to enhance the sustainability of brominated plastic WEEE mechanical recycling.