The Brief: Chemical versus mechanical recycling: an ongoing debate

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This report revisits the heated debate over chemical recycling and its role in a circular plastic economy. With strong opinions on both sides, it explores whether—and how—chemical recycling can complement mechanical recycling to reduce plastic waste and fossil dependency.

• Chemical recycling can process hard-to-recycle plastics, offering outputs close to virgin quality and potentially suitable for food-grade applications—something mechanical recycling still struggles to achieve.
• Environmental concerns persist, with critics citing high energy use, carbon emissions, and health risks; recent LCAs suggest chemical recycling is still more carbon-intensive than mechanical methods.
• Key stakeholders are calling for safeguards, including WWF and the Consumer Goods Forum, which recommend strict principles to ensure chemical recycling supports, not undermines, existing recycling efforts.
• Industry investments are accelerating, with major players like Dow, BASF, and Mura Technology scaling up pyrolysis capacity across Europe and the US, aiming to process hundreds of thousands of tonnes annually.
• Quality and infrastructure challenges remain, as pyrolysis oil requirements vary across sites, and questions linger over long-term food safety, system efficiency, and true circularity.
• Many experts agree that chemical and mechanical recycling must work together, with chemical recycling filling current gaps rather than replacing proven systems.

Chemical recycling is no silver bullet, but it’s no gimmick either. As companies scale up investments and pressure mounts to recycle more plastics into high-quality applications, chemical recycling could play a key supporting role. The industry’s challenge now is to set clear standards, mitigate environmental trade-offs, and ensure both recycling methods work in tandem to close the plastics loop.

As ecoprog stated in a previous report, “few topics in waste management […] polarize as strongly as chemical recycling does”. There has been plenty of discussion over the last few years about the suitability or unsustainability of chemical recycling for a circular and sustainable supply chain – but can we reach a consensus as to the role it should play in recycling efforts going forward?

In this edition of The Brief, we revisit the plentiful discussions held around chemical recycling and look for common ground upon which key players across the packaging industry can build towards a more sustainable recycling chain.

The theoreticals

WWF sparked conversation with a position paper weighing up the pros and cons of an industrialized chemical recycling system. It acknowledges that such processes as pyrolysis, gasification, and solvent-based extraction could help reduce demand for virgin and fossil-based plastics, as well as compensate for the current shortcomings of mechanical recycling. For example, it is generally agreed that the risk of contamination in mechanical recycling prevents its plastics from being used in food or hygiene products – an issue that chemical processes such as pyrolysis are not thought to face.

However, WWF expressed concerns that chemical recycling technologies “are energy-intensive, pose risks to human health, and/or will not be able to practically recycle plastic beyond what mechanical recycling already achieves.” It feared that widespread chemical recycling would result in higher carbon emissions, lessen consumers’ incentive to participate in reduction and reuse schemes, and overwrite current progress made to manage plastic pollution.

Therefore, the paper lays out ten principles thought to ensure that chemical recycling assists, rather than detracts from, progress towards a circular economy. These include preventing the diversion of resources from current recycling efforts and providing thorough proof of the effectiveness and personal and environmental safety of chemical recycling.

Plastic waste must always be directed to the most environmentally friendly form of recycling, said WWF, and must not be downcycled – yet ecoprog’s report insisted that a merit of chemical recycling is that it results in fully recyclable plastics without the necessity of downcycling.

Nevertheless, WWF argued that chemical and mechanical recycling should not be competing forces, but complimentary – a point that is frequently raised throughout the discussion.

A subsequent LCA conducted by The Consumer Goods Forum (CGF) supposedly found that the Py-CR process, in particular – chosen for being the ‘most commercially advanced chemical recycling pathway for hard-to-recycle plastics’ – reduces greenhouse gas emissions when compared to waste-to-energy incineration. For example, life cycle emissions for overall plastic films made with Py-CR were said to be 25% lower than those from fossil-based sources; this figure rises to 43% if the product is turned into PE or PP post-consumer flexible packaging, and to 48% if European electricity sources were to be decarbonized. Therefore, the company proposed that Py-CR should be implemented at an industrial level to replace energy incineration and reduce greenhouse gas emissions.

On the other hand, a recent report by Oeko-Institut suggests that chemical recycling is still a carbon-intensive process. Contrary to claims made by Chemical Recycling Europe that chemical processes will help the EU reach its recycling targets, the report estimates that emissions differ by 2.599kg CO2eq per kg of recyclate between mechanical recycling and pyrolysis, and from this, suggests that chemicals should be a ‘last resort’ in the process of recycling plastics. Even if renewable sources are burned in the pyrolysis oven, the remaining gases prevent the pyrolysis process from ever reaching net zero, the report says.

Regardless, CGF laid out its own six principles, largely reminiscent of WWF’s, yet it makes its own additions. For instance, “Py-CR should increase overall recycling volumes by only including input material that would not otherwise be recycled, and thus should not detract from mechanical recycling input streams.”

Drawing upon the results of the LCA, however, CGF admitted that Py-CR struggles to yield food-grade and high-quality plastics, as contaminants can build up and lead to losses. Marvin Kusenberg, PhD student and researcher at Ghent University, adds his own caveat: although waste streams can sometimes become contaminated, plastics derived from pyrolysis should not be considered any more dangerous than their fossil-based counterparts. He states that polymers derived from fossils and those from waste-derived ethylene are ‘essentially the same’, and therefore the chemical contamination of a product should not be a concern.

Growing popularity

What remains clear is that the industry is swiftly buying into pyrolysis. Various companies began to embrace the process in 2022 alone. Dow’s collaboration with Mura Technology to build and expand multiple US and European recycling facilities hoped to increase aggregate advanced recycling capacity by 600 kilotons by 2030; pX Group’s Saltend Chemicals Park and Itero Technologies’ at-scale demonstration plant aimed to process 80,000 and 27,000 tonnes of plastic waste a year, respectively. BASF signed an agreement with ARCUS Greencycling Technologies to purchase pyrolysis oil made from plastic waste, with the predicted outcome being an annual 100,000-tonne take-up of pyrolysis oils in the future.

Yet Michael Scriba of Scriba Consulting, former owner of MTM Plastics, remained sceptical. Speaking as a panellist during a CEFLEX event at FachPack 2022, he claimed to have watched chemical recycling processes falling in and out of fashion over the past thirty years.

Although he accepted that the direct input of the chemical industry might yield better results this time around, his main criticism lay in the high quality requirements of pyrolysis oils, which differ from cracker to cracker and drive up expenses – in his view, “to organize and coordinate these streams is still a challenge.” Furthermore, he warned that the industry cannot bring sustainable progress to a halt while it waits for chemical recycling to catch up.

“We have to get mechanical recycling right first,” agreed Graham Houlder, managing director of CEFLEX. However, claiming that 70% of existing packaging is applied to food products, he pointed out that mechanical recycling still cannot produce food-contact packaging. This is a serious detriment to his belief that recycling rates for flexible plastics in Europe must double, even triple, leading him to declare that the industry has no choice but to work towards chemical recycling – “if it doesn’t work, we can’t go circular.”

On the other end of the spectrum, Oeko-Institut’s report reiterates that further development is needed before mechanical recycling can tackle contact-sensitive packaging. Until this shortcoming can be resolved, the company states, chemically recycled plastic should be used in packaging that would come into contact with a product, although any additional layers of packaging should come from mechanical recycling.

Regardless of differing opinions, whether wide-scale industrial progress into mechanical recycling can even be achieved anytime soon is up for debate. Marvin Kusenberg admits that the long-term sustainability of using pyrolysis oils in large-scale industrial processes such as steam cracking, which were initially designed for fossil fuels, is unclear – that further testing and progress is still required in that regard. Perhaps this provides a justification for the financing and building of chemical recycling plants – or, as Kusenberg believes, the expense of fossil-based manufacture is forcing the industry’s hand.

Yet he, too, recognizes that chemical recycling should fill in the gaps for mechanical recycling, rather than superseding it. From his perspective, chemical recycling provides benefits that mechanical recycling cannot; for instance, he explains that chemical recycling does not exclusively result in polymers, but it can produce ‘high-value chemicals’ – a process that he considers recycling, even if EU legislation does not agree.

Others might argue that the carbon emissions – a drawback even Graham Houlder admitted to as he argued the case for chemical recycling on the CEFLEX panel – should not be overlooked, and that the ends do not justify the means. A report by RPA Europe, commissioned by the European Chemicals Agency, recorded that the 12-kiloton output produced through chemical cracking by Zagdaonkar every year yields 20% gas on top of the 75% oil; for Royco Beijing, its 6-kiloton output from pyrolysis yields 87% oil and 10% gas, and Mogami-Kiko’s 1-kiloton yields 79% oil and 12% gas. Although the oil outputs are undoubtedly greater, the resultant gas emissions are still substantial.

Where does that leave us?

Kusenberg makes the simple point that pyrolysis keeps waste away from landfill and lessens the industrial reliance on crude oil-derived feedstocks. These are features it shares with mechanical recycling.

The main selling points seem to be the other perks of chemical recycling, even those that are not fully proven yet. Chemical recycling can deal with mixed streams and hard-to-recycle plastics; the output is reported to be of virgin quality. Although the processes are generally carbon-positive, their emissions are still lower than incineration – a fate that might befall plastics that cannot be mechanically recycled.

The output of chemical recycling is also thought to be more versatile, although many take issue with this claim. An article by EREMA Group speculates that interest is building because the food safety of chemically recycled plastics is still a lingering question, and this touches on the many unknowns that remain where chemical recycling is concerned.

The controversy surrounding such processes has ignited a back-and-forth within the industry, particularly when it is compared to mechanical recycling. What can be (and seems to be) agreed on is that chemical recycling should be an addition to the proven merits of mechanical recycling, rather than detracting from it.

Although the extent to which chemical recycling should be utilized by the industry remains a point of contention, we have seen that companies are investing in the new process and trying new methods on an industrial scale, rather than within a laboratory. As new recycling plants open and investments are made, it is likely that facts and figures will start to emerge. Until that point, the only certainty is that the chemical and mechanical recycling industries are poised to function hand-in-hand, taking steps towards closing the loop on plastics and achieving true circularity.