Automated sorting technology for plastic waste

Recycling of plastic is an important component of the circular economy. Attaining high-quality recycled plastics requires the separation of plastic waste by type, color, and size. Sorting is extremely important in the mechanical recycling of plastics to increase the quantity and improve the quality and value of post-consumer plastics available for reprocessing. Sorting is also important in chemical recycling processes that do not tolerate well contaminants. Automated technology is key for sorting plastic objects in medium- to high-volume materials recovery facilities (MRFs), where it can improve the efficiency of separating different types of plastics while maintaining a high throughput of sorted materials, hence increasing revenue for MRFs. Current limitations encountered at MRFs in sorting plastic can potentially be overcome using artificial intelligence (AI)-based sorters and robots. An overview of automated sorting technology is presented here, starting with the spectroscopic techniques commonly used for identifying the type of plastic, moving on to the use of machine learning (ML) and AI to identify plastic pieces based on their spectra, to the incorporation of AI/ML in commercial equipment for sorting plastic, all the way to the development of robots for handling waste and their utilization for plastic sorting. Improvements and/or new solutions in the automated sorting of plastics are forthcoming.