Plastic Recycling Deodorization and Decontamination: Expert Interview

As recyclate quality requirements continue to rise, recyclers face increasing pressure to deliver materials with low odor levels, consistent properties, and suitability for demanding applications. At the same time, they must operate economically and sustainably.

With its integrated recycling technology, Coperion addresses deodorization and decontamination throughout the entire recycling process. The first step begins during washing and material preparation, followed by intensive devolatilization in the Coperion twin screw extruder and completed by the EcoFresh silo degassing system. This comprehensive approach not only improves odor quality and recyclate performance but has also been validated for the production of food-grade recycled HDPE and PP. In June 2026, Coperion received a Letter of No Objection (LNO) from the U.S. Food and Drug Administration (FDA), confirming the effectiveness of its technologies for rHDPE and rPP recycling. Coperion is the first provider of complete decontamination systems featuring twin screw extruders and EcoFresh silo degassing to offer the market a highly efficient solution for the production of food-grade recyclates, covering capacities from small throughputs up to 6,000 kg/h.

We spoke with Jochen Schofer, Head of Sales at Coperion, about the growing importance of deodorization and what the FDA confirmation means for the recycling industry.

Recyclers have traditionally focused on throughput and material recovery. Why has deodorization become such an important topic today?

Because the market's expectations of recyclates have changed dramatically.

Today, it's no longer enough to simply produce recycled material. Brand owners, recycling companys and consumers expect recyclates to perform similarly to virgin plastics. One of the most noticeable quality criteria is odor. If a recycled material has an unpleasant smell, its potential applications become very limited.

This is particularly true for packaging, household products, consumer goods and many technical applications. Effective deodorization has therefore become a key factor in increasing the value and marketability of recyclates.

What causes these odors in post-consumer recyclates?

Post-consumer plastic waste often contains volatile organic compounds (VOCs), residual substances and contaminants.

Even after washing, traces of these substances can remain in the material. These residual compounds are often responsible for unwanted odors and can negatively affect the perceived quality of the recyclate.
The challenge is not only to remove these substances effectively but to do so in an energy-efficient and economically viable way.

How does Coperion address this challenge of deodorization?

We approach deodorization as steps along the whole recycling process.

The first important step takes place during material preprocessing. With efficient Herbold Meckesheim washing technology, raw material is not only cleaned but also deodorized. Efficient washing lines remove a significant portion of contaminants and odor-causing substances before the material even reaches the recycling process.

The second stage takes place in the Coperion twin screw extruder. Here, the recyclate is melted, intensively mixed, homogenized and degassed. Thanks to optimized screw configurations and process conditions, a large proportion of volatile organic compounds are reliably removed within the twin screw extruder.

The third and final stage is the EcoFresh silo degassing. There, the compounded material undergoes thermal post-treatment, where remaining volatiles and residual odors are removed. This final polishing step allows recyclates to reach a quality level that, in terms of odor characteristics, can approach that of virgin materials.

What makes our solution unique is this integrated approach. Each process step contributes to the overall deodorization performance, resulting in significantly higher recyclate quality.

You often speak about deodorization as a process rather than a single technology. Why is that important?

Because no single process step or technology can remove all contaminants and odor-causing substances on its own.

Successful deodorization begins with effective washing and material preparation. It continues with intensive devolatilization in the extruder and is completed by thermal post-treatment in EcoFresh.

Each technology removes different types of contaminants and volatile compounds. When these technologies are optimally combined, they create a highly efficient overall decontamination result.

This integrated approach was also one of the key reasons why we have received the FDA Letter of No Objection for food-grade rHDPE and rPP. The FDA confirmation validates not just one machine, but the effectiveness of the entire process concept. 

What opportunities does this FDA approval create for recyclers?

It opens the door to significantly higher-value applications.

With Coperion technology, recyclers can produce food-grade regranulate from HDPE milk jugs or fruit juice bottles and reuse it to manufacture similar bottles or related products. Food containers, cups, bowls and trays made of PP can be recycled into new packaging for direct contact with food. Depending on the application, recycled content levels of up to 100 percent are possible.

Is EcoFresh only relevant for food-grade recycling?

Not at all.

The majority of recycling applications today are not food-contact applications, but they still require high-quality, low-odor materials. Household products, cosmetics packaging, detergent containers, automotive components, consumer goods and many other products all benefit from improved recyclate quality.

EcoFresh helps recyclers meet these growing quality expectations while simultaneously improving process efficiency.

What advantages does EcoFresh offer when integrated into existing recycling lines?

Flexibility was a key development objective.

EcoFresh has a compact footprint and can be installed either inside or outside production buildings. It can also be integrated relatively easily into existing recycling operations, allowing recyclers to upgrade product quality without extensive modifications to their production infrastructure.

This makes the technology attractive both for new installations and for modernization projects.

How can recycling companies test plastic recycling technology using their own material streams?

At our test centers, customers can perform comprehensive trials using their original materials under realistic production conditions.

Shredding, washing and material preparation can be tested at the Herbold Meckesheim Test Center. At the Coperion Recycling Innovation Center material handling, discharging, feeding, extrusion, compounding, pelletizing and silo degassing can be tested. Together, Coperion and Herbold replicate the entire recycling process at their test centers.

This allows recyclers to validate performance, product quality, odor reduction, decontamination efficiency and process efficiency before making investment decisions.

Looking ahead, what role will deodorization play in the future of plastics recycling?

I believe deodorization will become one of the defining quality criteria for recyclates.

As legislation, brand commitments and consumer expectations continue to drive higher recycled-content targets, recyclates will increasingly be required to compete directly with virgin materials. This means quality, consistency, safety and sensory properties will become more important than ever.

What makes me particularly confident about the future is that we have proven solutions for every stage of the deodorization process. From washing and cleaning through extrusion and final silo treatment, we can help recyclers produce materials that meet increasingly demanding quality expectations.

Technologies that efficiently remove odors and contaminants will play a central role in high-value recycling applications. The FDA confirmation for food-grade rHDPE and rPP demonstrates what is possible when advanced extrusion and deodorization technologies work together as an integrated solution.
For us, this is not only a milestone for food-grade recycling – it is proof that high-quality recyclates can unlock entirely new opportunities for the circular economy.

Jochen Schofer is Head of Sales Recycling at Coperion and supports customers worldwide in implementing advanced solutions for plastics recycling, decontamination and deodorization.