Closing the Loop: Polyester recycling trials offer promise and challenges
A new report by Accelerating Circularity, a non-profit focused on textile-to-textile recycling, highlights the opportunities and challenges in closing the loop on polyester recycling. The report details a series of global trials conducted in 2022 involving 43 companies, at various stages of the textile supply chain, from collection and sorting to recycling and manufacturing.
Polyester, derived primarily from crude oil, accounts for roughly 57 per cent of global fiber production. While recycling is increasing, it predominantly involves converting PET bottles into recycled polyester (rPET). The report emphasizes the urgent need for textile-to-textile (T2T) recycling to reduce the estimated 92 million metric tons of textile waste landfilled annually.
The trials focused on stress-testing existing systems, with a goal of sourcing 50 metric tons of feedstock. Despite known bottlenecks in sorting and pre-processing, 17.4 metric tons were ultimately sourced. The trials evaluated both thermomechanical and chemical recycling methods, assessing the viability of producing high-quality rPET from various feedstocks.
Study findings
Sorting: Automated sorting using Near Infrared (NIR) technology proved significantly more accurate than manual processes, reducing feedstock loss by up to 36 per cent. However, de-trimming (removing non-recyclable components) remains a manual and time-consuming bottleneck.
Pre-processing: The trials highlighted the need for clear definitions and specifications in preparing feedstock for different recycling technologies. Thermomechanical methods generally accept de-trimmed garments, while chemical recycling often requires further size reduction.
Recycling: While thermomechanical recycling requires high-purity PET feedstock, chemical recycling shows promise in handling non-PET components. However, many chemical processes produce monomers that need further polymerization before yarn production, often requiring collaboration with the plastics or virgin materials industries.
The report illustrate these findings through a few case studies. For example, supply chain 1, involving workwear textiles, revealed that even garments assumed to be 100 per cent PET can contain contaminants that disrupt thermomechanical recycling. Similarly, supply chain 5, focusing on duvets and garments, showed that automated sorting with NIR technology at TOMRA's test center significantly improved feedstock purity.
Contamination, manual nature major challenges
The report identifies several challenges. It highlighted, contamination which means Ensuring feedstock purity remains a major hurdle, particularly for thermomechanical recycling. Similarly, the manual nature of de-trimming and the lack of standardized pre-processing methods pose significant bottlenecks. And the limited capacity for chemical recycling and polymerization at commercial scale remains a barrier. The cost-effectiveness of T2T recycling, particularly for small-scale trials, is a concern.
Despite these challenges, the report highlights opportunities. It says emerging chemical recycling technologies offer potential solutions for handling complex blends and contaminants. However, partnerships across the textile supply chain are crucial for developing and scaling circular systems. And Designing products with recycling in mind can significantly improve the efficiency and viability of T2T recycling.
The moot point is that the landscape of polyester recycling is a fast evolving one, with growing legislative pressure, advancements in technology, and growing demand for sustainable textiles. The report concludes with a call to action, urging stakeholders to address the remaining system gaps and accelerate the transition to a circular textile economy.
"Circularity systems will not build themselves," the report states, emphasizing the need for collective action to solve fashion's waste problem. By fostering collaboration, investing in technology, and designing for circularity, the industry can unlock the potential of polyester recycling and create a more sustainable future.