Assessment of Performance and Challenges in Use of Commercial Automated Sorting Technology for Plastic Waste

Abstract

Recycling plastic is an important step towards a circular economy. Attaining high-quality recycled plastics requires the separation of plastic waste by type, color, and size prior to reprocessing. Automated technology is key for sorting plastic objects in medium- to high-volume plants. The current state of the art of commercial equipment for sorting plastic as well as challenges faced by Material Recovery Facilities (MRFs) to sort post-consumer plastics are analyzed here. Equipment for sorting plastic recyclables were identified using publicly available information obtained from manufacturers’ websites, press releases, and journal articles. Currently available automated sorting equipment and artificial intelligence (AI)-based sorters are evaluated regarding their functionality, efficiency, types of plastics they can sort, throughput, and accuracy. The information compiled captures the progress made during the ten years since similar reports were published. A survey of MRFs, reclaimers, and brokers in the United States identified methods of sorting used for plastic, sorting efficiency, and current practices and challenges encountered at MRFs in sorting plastic recyclables. The commercial sorting equipment can address some of the challenges that MRFs face. However, sorting of film, multilayered, blended, or mixed-material plastics is problematic, as the equipment is typically designed to sort single-component materials. Accordingly, improvements and/or new solutions are considered necessary.

Challenges for Future Robotic Sorters of Mixed Industrial Waste: A Survey

“…1) Similar to this study, Bogue et al [25], Gibson [12], and Lubongo et al [39] enumerated several practical sorting machines to outline what current waste-specific systems can manipulate (e.g. sort and disassemble) the limited target waste.…”

“…They are included in this survey because of related techniques that exist to sort solid waste. For example, some existing technologies can sort aluminum scraps [74], [75], plastics [22], [39], [76], beverage containers [77], and batteries [78], [79], [80]. These objects are also often included in mixed industrial waste.…”

“…Some of these articles summarize waste sorting systems and approaches for different waste source domains, including WEEE [13], [21], [25], [35], [37], municipal [1], [2], [14], [16], [17], [19], [34], and CND [23], [30], [33], [36] waste. Furthermore, several assessment and evaluation methods for sustainability in construction automation and robotics [81], technological developments for robotic sorting of plants [82], performance in sorting technology [39], and waste treatment systems [83] have also been proposed.…”

A Review and Bibliometric Analysis of Sorting and Recycling of Plastic Wastes

“…Sorting plastic into different polymer types is often achieved by using the physical sorting-enabling properties of certain materials/polymers. Spectroscopy and x-ray technology can be used to sort plastics by resin [42,43]. Separation often takes place in handling architectures that are built and developed to improve the behavior of waste particles concerning the chosen property to perform the separation.…”

Mid-infrared spectroscopy and machine learning for postconsumer plastics recycling

“…28,29 This is because MRFs currently rely on air jets, magnetic separators, mechanical pistons, and human intervention to sort PCPW, all of which are methods that have been deemed insufficient to meet growing recycling demands. 30,31…”