Decarbonisation Technology May 2025 Issue

Advancing the circular economy for waste plastic Advanced recycling processes can turn what was once considered a waste product into a valuable commodity

Geoff Brighty Mura Technology

I n September 2024, scientists at the University of Leeds published the results of an experiment that used real-world data and machine learning to simulate waste disposal numbers in countries around the world for the year 2020 ( Cottom, Cook, & Velis, 2024 ). They calculated that more than 52 million tonnes of mismanaged plastic waste entered the environment that year, with 70% of it coming from just 20 countries. This problem has only grown in scale over time. Even since 2020, the production of plastics has continued to climb ( Statista, 2024 ), and much of the plastic produced each year is disposed of within a year of being manufactured ( Hopewell, Dvorak, & Kosior, 2009 ). So far, humanity has struggled to find solutions to manage the volume and range of plastics produced. Plastic has become ubiquitous in our global economy due to its many essential applications. However, this variety – the differences in chemical makeup between various types of plastic – makes mixed streams of plastic waste durable but very difficult to recycle, leading to mismanagement and the pollution of our natural environment. Solutions that can scale to meet this global challenge are urgently required. As the world attempts to transition away from the use of fossil resources in sectors such as power generation and transport, parts of the world are also attempting to transition from a linear to a circular economy. To accomplish this, a new set of technologies intended to revolutionise how petrochemical products are used in the manufacture of plastic packaging are beginning to reach key stages of successful commercial implementation.

Despite not currently being defined in any European regulation, a wide array of advanced recycling (sometimes referred to as ‘chemical recycling’) technologies is poised to transform how the global economy manages and re- circulates the mountains of plastic waste it produces ever year. Advanced recycling technologies Traditional mechanical recycling can process some of the world’s plastic waste, particularly single-polymer types. This process involves sorting, shredding, washing, and separating the waste into similar polymer groups, which are heat treated to remove odour and then melted and formed into pellets. These pellets can be remelted, becoming the constituent ingredients for new plastic products, albeit not those intended for contact-sensitive applications, such as food or medical packaging. However, a considerable proportion of plastic waste cannot be mechanically recycled, such as contaminated food-contact films or layered materials. This is where advanced recycling comes into play. The European Coalition on Chemical Recycling broadly defines advanced recycling as “converting polymeric waste by changing its chemical structure to produce substances used as products or raw materials”. Importantly, this definition excludes processes that yield products “used as fuels or [as] means to generate energy”. There is a need for recycling solutions that can process a wider variety of polymer types together, such as the mixed streams of hard-to- recycle plastic waste produced by households, economically and with minimal impact on the environment. It is with these considerations in