Upcycling of PET waste using bioelectrochemical systems (UPSCALE)

Polyethylene terephthalate (PET) is one of the most used thermoplastic polymers for liquid drinks and food containers. PET is a high molecular weight polymer, composed of terephthalic acid (TPA) and ethylene glycol (EG).

PET-based products such as those consisting of multilayer films and fibres do not have the same recycling efficiency as PET bottles, as additional components (polyolefins, ethylene vinyl alcohol, additives, fillers and pigments) prevents a sufficiently high purity and yield of secondary chemical or monomeric feedstocks, when using conventional mechanical recycling processes.

In order to address the global challenges associated with plastic waste, there is a need for non-toxic, chemical transformation methods of the more complex PET waste products to value added chemicals as an attractive alternative to support a circular economy for plastic waste.

In this project, we aim to establish and demonstrate a sustainable and efficient process for upcycling of PET plastic waste into value-added chemicals as building blocks for recyclable materials.

This will be achieved by conducting a holistic approach, where a mild refining process, alkaline oxidative solvolysis of real PET waste streams, such as monolayer and multilayer PET plastic waste, is combined with bioelectrochemical conversion systems where sulfate reducing bacteria (SRB) and carbon chain elongating bacteria are employed for the upcycling of refined PET monomers to medium chain carboxylates.