A Detailed Analysis of the Morphological Composition of Selectively Collected Plastics and Metals: A Case Study of Four Voivodeships in Poland

This article presents the results of research on the morphological composition of selectively collected plastics and metals conducted in four voivodeships in Poland from late 2024 to early 2025, before the introduction of the deposit-return system. A very detailed classification of the morphological composition of the studied plastics and metals into 29 groups was adopted, which distinguishes this study from other research and makes it possible to assess the quality of selectively collected waste. A detailed analysis of morphological composition enables an in-depth assessment of the potential of individual fractions for mechanical recycling, chemical recycling, or energy recovery. The results show that contamination in selectively collected plastics and metals, i.e., fractions not covered by this collection scheme, accounted for approximately 22% of the total mass. The largest share among the studied fractions consisted of films of various types, which accounted for approximately 24% of the mass of selectively collected waste. Assuming an 85% sorting efficiency for marketable plastics and metals, a maximum of approximately 57% of the mass of selectively collected plastics and metals can be directed to mechanical recycling. The remaining fraction, excluding PVC and glass, can be used for energy recovery or, in the future, partly directed to chemical recycling. The article also discusses factors that will affect changes in the morphological composition of selectively collected waste, including the deposit-return system, extended producer responsibility, and packaging eco-design.