CLEANSTREAM Technology - Food Grade PP from Post-Consumer sources

Polypropylene accounts for c20% of the world's plastic; predominantly used to make pots, tubs, and trays (PTT) for food applications (WRAP, 2018). In the UK, we use c390,000 tonnes/year of polypropylene in packaging applications, the majority (c70%) of which is used to produce food-grade packaging (WRAP, 2019). Yet, since there is no approved food-grade process method for mechanically recycling polypropylene, the production of polypropylene food packaging currently relies on virgin polymers (Inside Packaging, 2021). Instead, post-consumer polypropylene food packaging is down-cycled into lower-value applications with less stringent regulatory requirements; e.g., automotive (ranging from interior design items to mudguards), other packaging applications (e.g., paint pots, pallets, crates), and horticulture (e.g., plant pots).

In turn, the absence of a closed-loop recycling route for post-consumer polypropylene food packaging severely restricts value creation and recycling rates compared to other plastics. In 2017/18, around 60% of plastic bottles were collected by kerbside collection schemes, compared to only 38% for PTT (WRAP, 2019). Consequently, the UK recycled content of polypropylene PTT in consumer packaging is only 5% (WRAP, 2019), compared to an average recycled content of 13% across all UK plastics packaging (WRAP, 2020). With a UK Plastics Pact target of reaching an average recycled content of 30% across all plastics packaging by 2025, the development of a process to produce food-grade recycled polypropylene is a priority for the Industrial Strategy Challenge Fund Smart Sustainable Plastic Packaging. Scientists also recently called for an end to the production of virgin plastics by 2040\.

The challenge is to develop an economically viable process to separate post-consumer food-contact polypropylene PTT from non-food-use polypropylene PTT, meeting FSA/EFSA requirements for infeed to a recycled polypropylene process to comprise a high percentage of food-contact PTT. Unlike PET and HDPE bottles, which are readily sorted and recycled to produce food-grade materials, the diverse applications of polypropylene PTT in domestic waste (spanning food, personal care, household chemicals) makes sorting to high accuracy required for food-grade materials extremely challenging. The situation is further compounded by potential container misuse.

With public funding, plastics recycling giant Plasgran, with TOMRA Sorting, Maynard & Harris, RPC Containers, and Massmould, will develop and demonstrate the world's first mechanical recycling process to produce food-grade recycled polypropylene. Our innovative approach is uniquely designed for integration within existing waste streams and infrastructure, relying on a state-of-the-art combination of online sensor technologies coupled with machine learning algorithms to sort the infeed into food/non-food-contact materials.