Does PET trays sorting affect the sustainability of plastic waste? An LCA and cost-revenue approach

Currently, the management of polyethylene terephthalate (PET) trays waste is still challenging since this packaging af-fects the consolidate recycling of PET bottles. It is important to separate PET trays from the PET bottle waste stream to avoid its contamination during recycling process and to recover a higher amount of PET. Hence, the present study aims to evaluate the environmental (by means of Life Cycle Assessment, LCA) and economic sustainability of sorting PET trays from the plastic waste streams selected by a Material Recovery Facility (MRF). For this scope, the case of a MRF in Molfetta (Southern Italy) was chosen as reference, and different scenarios have been evaluated by assuming different schemes of manual and/or automated PET trays sorting. The alternative scenarios did not achieve very pro-nounced environmental benefits over the reference case. Upgraded scenarios resulted in overall environmental im-pacts approx. 10 % lower as compared to the current scenario, with the exception of the climate and ozone depletion categories where differences in impacts were much higher. From an economic point of view, the upgraded scenarios achieved slightly lower costs (<2 %) than the current one. Electricity or labour costs were necessary in upgraded scenarios, but in this way fines for PET trays contamination in PET streams for recycling were avoided. Im-plementing any of the technology upgrade scenarios is then environmentally and economically viable, when the PET sorting scheme is performed in appropriate output streams through optical sorting.

Automated summary

The management of PET trays waste poses challenges for recycling PET bottles. This study evaluates the environmental and economic sustainability of sorting PET trays from plastic waste streams. Alternative scenarios showed limited environmental benefits, with overall impacts 10% lower than the current scenario but significant differences in climate and ozone depletion. Upgraded scenarios achieved slightly lower costs (<2%) by avoiding fines for PET trays contamination. Implementing technology upgrades for PET sorting through optical sorting is both environmentally and economically viable.