Battling plastic waste: Why advanced sorting is key to EU’s transition to a circular economy

One of the main challenges with recycling plastic waste is contamination or mixing different materials, which weakens the quality of the final recycled products. Along with designing plastic materials that are easier to recycle, advanced sorting technologies play a key role in eliminating impurities. The effectiveness of advanced recycling technologies for post-consumer waste largely depends on the quality of the materials being processed.

Let’s take pyrolysis as an example—a recycling technology designed to handle plastics that cannot be mechanically recycled. Pyrolysis breaks down these complex plastics through a thermal process, transforming them into valuable resources such as oils and gases, which can re-enter the plastic production cycle as raw materials. This not only reduces waste but also provides a circular solution that aligns with the EU's recycling and sustainability objectives.

However, despite its potential, pyrolysis faces significant challenges, especially regarding the quality of the feedstock. Several technology developers are working on advancing pyrolysis, but they all encounter the same issue: the process demands clean, specific plastic waste streams to produce high-quality oils. If the feedstock is contaminated or composed of mixed materials, the resulting oil requires extensive post-treatment and upgrading, which not only increases complexity and cost but also lowers the oil's value. This makes the final product less appealing to off takers, reducing its market viability.

Therefore, it is crucial that plastic waste is carefully sorted and cleaned. Ideally, the feedstock should consist of about 85% polyethylene (PE) and polypropylene (PP)—two of the most common plastics. When this condition is met, the result is a high-quality oil which can be reintegrated into the plastic manufacturing cycle.

It is important to acknowledge that not all plastics can be recycled in a feasible way or at all for that matter. There will always be a “rest-stream” that ends up incinerated.

Currently, the landscape of investment in advanced sorting technologies is marked by uncertainty. The complexity and diversity of plastic waste, coupled with fluctuating market prices for recycled materials, contribute to the challenge. What is clear though, is that the most efficient recycling can be achieved through clean and uniform waste streams.

To maximise the reuse of all waste streams, it’s essential to adopt a customised strategy. Conducting a detailed market analysis and creating a process design that specifically addresses the types of materials in question along with the existing operational constraints, is vital for a competitive business case.

This means, that certain plastic types, such as biodegradable plastics are best recycled using depolymerisation/dissolution and plastics such as polyethylene terephthalate (PET) bottles are allocated for mechanical material recovery while others like PE and PP are recycled using pyrolysis.

The resources we need are no longer in the ground, but in landfills. Advanced sorting gives a whole new perspective on waste infrastructure and encourages a better understanding of the various material properties. It drives innovation, new business models, and a broader acceptance and preference for recycled content in the market.

A reliable sorting infrastructure assures manufacturers of a consistent supply, encouraging them to invest in processes and products that use recycled plastics. This is crucial for EU’s transition to a circular economy. However, embracing the circular economy is everyone's business and the challenges discussed here are not unique to the EU—they are part of a global narrative where knowledge, strategies, and lessons learned can elevate the battles against plastic waste on an international scale.