D5.2: Improving plastic waste collection and sorting

Improving plastic waste collection and sorting is a critical step towards increasing recycling rates and enabling the production of high-quality recycled plastics suitable for high-quality applications. Differences in collection systems, sorting practices, and feedstock composition across Member States can significantly influence the quality and performance of recyclates, with direct implications for material recoverability, consistency, and downstream use. Deliverable D5.2 of the STOPP project investigates how different plastic packaging collection systems affect the quality of recycled rigid polypropylene (PP). The study focuses on home-separated (HS) and posthome-separated (PHS) collection schemes, using feedstock sourced from selected regions in Finland and Germany. Through controlled laboratory-scale simulations of mechanical recycling processes, followed by comprehensive material characterisation, the report assesses the impact of collection and sorting on recyclate purity, thermal behaviour, melt flow properties, and mechanical performance. The results show that rigid PP feedstock obtained from both HS and PHS systems across all regions is predominantly composed of PP copolymers and can be successfully mechanically recycled. However, clear differences emerge in terms of material consistency and purity. Home-separated collection systems, particularly in Finland, consistently yield recyclates with lower variability, more stable melt flow behaviour, and higher material purity compared to post-home separated systems. In contrast, comingled collection systems (mixed plastic packaging streams) exhibit a higher risk of crosscontamination, notably from flexible packaging materials such as polyethylene, which can affect recyclate properties and processability. A semi quantitative analysis of Non-Intentionally Added Substances (NIAS) shows that collection systems can affect on the chemical contamination of recycled rigid PP. More precisely, post-home separated (PHS) streams tend to show higher level of residue related compounds while home-separated streams (HS) decrease the transfer of NIAS in general. The significant Swiss partner funded by Funded by the European Union. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or REA. Neither the European Union nor REA can be held responsible for them. variability within both systems emphasizes the role of input composition, consumer behaviour as well as local waste handling practices. Despite these differences, the mechanical and thermal properties of all recycled PP samples remain within ranges suitable for common processing applications such as injection moulding and compounding. This demonstrates that, with appropriate sorting and processing, post-consumer rigid PP packaging can deliver technically viable recyclates. Nevertheless, the findings underline the importance of polymer-specific and separate collection systems in achieving higher quality and more predictable recycled materials. Overall, this deliverable provides evidence-based insights into the influence of collection and sorting practices on recycling outcomes. The results support the development of best practices for waste collection systems that can enhance recycling efficiency, improve recycled material quality, and strengthen the role of recycled plastics within a circular economy for food and consumer packaging.