66.3 percent of household-near PET trays are collected by the dual systems in Germany. However, only 17.5 percent are recycled. A current report on PET tray recycling (commissioned by: Forum Rezyklat/GS1 Germany GmbH) makes it clear that large quantities are lost, above all, between collection and recycling.
The crucial figure lies in between: 73.6 percent of the collected PET trays are rejected as waste during the sorting process and are subsequently predominantly recycled thermally. By way of comparison, the recycling rate for plastic packaging as a whole was 52.2 percent in 2023. The problem with PET tray recycling therefore lies less in collection than in sorting and recovery.
PET systems are designed for bottles
As a main cause, it states the report the strong focus of existing sorting fractions and recycling plants on PET bottles. As a result, trays are frequently diverted from the recycling stream. In addition, at around five percent, PET trays account for a comparatively small proportion of the total volume of plastic packaging. According to the report, this reduces the economic incentives for recyclers to develop dedicated processes for this type of packaging.
A report by the Federal Environment Agency regarding the practice of sorting and recycling confirms the difficulties. The PET recyclers surveyed handle trays very differently. Accordingly, transparent monolayer trays can in some cases be recycled together with transparent PET bottles. However, the recyclers' statements regarding the possible proportion range from zero to 100 percent. Multilayer trays were cited by five of the six reference plants considered as a contaminant in the reject.
Monolayers and multilayers differ
The design of the packaging plays an important role in this. Monolayer trays are made of PET and are used, for example, for fruit and vegetables. Multilayer trays, on the other hand, contain additional sealing or barrier layers made of polymers such as PE or PA and are frequently used for meat, cold cuts or cheese products. Such foreign polymers can impair the quality of the recovered PET recyclate.
According to the market data in the final report, a total of 144,000 tonnes of PET trays and comparable PET packaging were used in Germany in 2024. Of this total, 94,600 tonnes were attributable to monolayer and 49,300 tonnes to multilayer applications. PET trays and food trays alone accounted for 101,800 tonnes.
Additional preparation steps are required for multilayer trays. The final report specifically mentions the delamination of composites such as PET/PE or PET/PE/EVOH. This allows foreign polymer fractions to be reduced and the purity and processability of rPET to be improved. However, the additional process stage also increases plant complexity and costs.
Technology must distinguish between skin and bottle
Another difficulty lies in sorting technology. Common near-infrared spectroscopy reliably identifies PET as a type of plastic. However, PET bottles and PET trays have very similar spectra. Reliable differentiation based solely on the material is therefore difficult, especially with dirty, printed or deformed packaging.
The final report therefore recommends that PET trays should be positively sorted in future rather than merely being treated as a residue of PET bottle sorting. From a perspective of future development, imaging sensor systems with AI-supported object recognition could help. According to the study, such systems are already being used in individual plants to separate PET trays and PET bottles.
However, technical solutions alone are not enough to expand tray-to-tray recycling. The authors also see a need for action regarding uniform sorting specifications, economic incentives and reliable off-take channels. Differing requirements of the systems currently make the targeted provision of suitable PET tray fractions for recyclers difficult.
Sources: Final report on PET tray recycling, practice of sorting and recovery of packaging within the meaning of Section 21 of the German Packaging Act (VerpackG) 2023/2024
