Analysis of trade-offs of post-sorting plastic packaging
5 affiliations
- 1Laboratory for Circular Process Engineering (LCPE), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Kortrijk, Belgium
- 2Chair of Aroma and Smell Research, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- 3Laboratory for Chemical Technology (LCT), Department of Materials, Textiles and Chemical Engineering, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium
- 4Circular Plastics, Department of Circular Chemical Engineering, Faculty of Science and Engineering, Maastricht University, Maastricht, the Netherlands
- 5Laboratory for Circular Process Engineering (LCPE), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Kortrijk, Belgium. [email protected]
Abstract
Increasing recycling rates requires not only better technologies but also smarter collection of plastic packaging waste1. Source separation—sorting materials such as plastics and metals at the household level—captures substantial waste volumes2,3, yet significant quantities still remain in the residual household waste fraction owing to misthrows and non-participation4,5. Post-sorting of mixed waste has been proposed as a one-bin alternative to boost capture6,7, despite concerns that contamination could compromise recycling quality7–9. Here we show, based on samples collected from one single material recovery facility, that bale purity, expressed as percent target polymer, is similar across source-separation and post-sorting pathways, but post-sorted bales contain more contaminants, including prohibited metals such as cadmium and lead. Post-sorted samples have higher moisture and dirt content8, which can lead to increased complex volatile organic compounds and necessitate additional washing. Concentrations of metals and halogens are elevated owing to non-packaging items, potentially compromising recycling quality and further complicating both mechanical and chemical recycling processes10,11. Although post-sorting can be a useful supplement, it should not replace source separation. Our results demonstrate that post-sorting can increase feedstock for recycling, but it also acts as a pathway for certain contaminants to enter plastic packaging waste, raising concentrations above typical levels, with potential risks to human health if these contaminants are not removed before recyclate production. As post-sorting of residual waste becomes crucial to meet circularity targets, these findings are particularly relevant. An analysis of post-sorting plastic packaging shows that target polymer purity is similar across source-separation and post-sorting pathways, but post-sorted plastics contain more contaminants that need to be removed before recyclate production.
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BibTeX
@article{schmuck2026analysis,
title = {{Analysis of trade-offs of post-sorting plastic packaging}},
author = {A Schmuck and Tiago Gomes de Aragão Belé and Daniël Withoeck and Kevin M. Van Geem and Kim Ragaert and Steven De Meester},
journal = {Nature},
year = {2026},
month = jun,
doi = {10.1038/s41586-026-10606-4},
url = {https://doi.org/10.1038/s41586-026-10606-4},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Analysis of trade-offs of post-sorting plastic packaging
AU - A Schmuck
AU - Tiago Gomes de Aragão Belé
AU - Daniël Withoeck
AU - Kevin M. Van Geem
AU - Kim Ragaert
AU - Steven De Meester
PY - 2026
DA - 2026/06/03
JO - Nature
DO - 10.1038/s41586-026-10606-4
UR - https://doi.org/10.1038/s41586-026-10606-4
AB - Increasing recycling rates requires not only better technologies but also smarter collection of plastic packaging waste1. Source separation—sorting materials such as plastics and metals at the household level—captures substantial waste volumes2,3, yet significant quantities still remain in the residual household waste fraction owing to misthrows and non-participation4,5. Post-sorting of mixed waste has been proposed as a one-bin alternative to boost capture6,7, despite concerns that contamination could compromise recycling quality7–9. Here we show, based on samples collected from one single material recovery facility, that bale purity, expressed as percent target polymer, is similar across source-separation and post-sorting pathways, but post-sorted bales contain more contaminants, including prohibited metals such as cadmium and lead. Post-sorted samples have higher moisture and dirt content8, which can lead to increased complex volatile organic compounds and necessitate additional washing. Concentrations of metals and halogens are elevated owing to non-packaging items, potentially compromising recycling quality and further complicating both mechanical and chemical recycling processes10,11. Although post-sorting can be a useful supplement, it should not replace source separation. Our results demonstrate that post-sorting can increase feedstock for recycling, but it also acts as a pathway for certain contaminants to enter plastic packaging waste, raising concentrations above typical levels, with potential risks to human health if these contaminants are not removed before recyclate production. As post-sorting of residual waste becomes crucial to meet circularity targets, these findings are particularly relevant. An analysis of post-sorting plastic packaging shows that target polymer purity is similar across source-separation and post-sorting pathways, but post-sorted plastics contain more contaminants that need to be removed before recyclate production.
SN - 0028-0836
SN - 1476-4687
ER -