DePoly opens industrial PET recycling plant

DePoly has opened its first industrial scale showcase plant in Monthey, Switzerland, moving its PET and polyester depolymerisation technology into continuous customer qualification and production work.

With nominal annual input capacity of approximately 500 tonnes, the facility will process used bottles, food packaging, coloured PET, complex films, and polyester textiles. It will also generate operating data, qualify customer feedstocks, and refine the process ahead of the company’s proposed commercial expansion.

DePoly breaks PET into its original chemical building blocks, purified terephthalic acid and monoethylene glycol. Once recovered and purified, those monomers can return to conventional polyester and PET manufacturing rather than being confined to lower grade applications.

Light activated chemistry allows the depolymerisation stage to be completed in less than an hour without the high temperatures and additional pressure associated with several other chemical recycling routes. The process is intended principally for material that is unsuitable for straightforward mechanical recycling because of contamination, colour, construction, or previous processing history.

Located within the CIMO industrial park, the Monthey installation has created 12 direct jobs and more than 30 indirect roles. Its position in an established chemical cluster provides access to technical services and infrastructure while keeping the plant close to DePoly’s headquarters in Sion.

The next planned step is a commercial facility capable of processing 50,000 tonnes annually. Moving from 500 tonnes to that scale will require feedstock contracts, sorting capacity, storage, contamination controls, utilities, monomer purification, maintenance systems, off-take agreements, and working capital to expand together.

PET remains widely used in bottles, trays, jars, films, and thermoformed food containers because its processing characteristics and barrier performance are well understood. Recovered material can return to food contact applications where the recycling technology, decontamination process, traceability, and regulatory evidence meet the required standards.

Food grade circularity depends on feedstock quality

Mechanical recycling remains the most direct route for clean, well sorted PET bottles, while chemical recycling must justify its additional process complexity by recovering material that would otherwise be downcycled, exported, incinerated, or discarded. Mixed colours, multilayer structures, textiles, and contaminated packaging provide the strongest potential feedstock base.

That separation between recycling routes remains commercially important. Clear bottles, removable labels, compatible closures, and effective deposit or kerbside collection improve material recovery regardless of the technology used later, while poorly designed packs increase sorting losses and treatment costs.

The consistency of the recovered terephthalic acid and monoethylene glycol will determine whether resin producers and packaging converters accept the output at scale. Variations in purity, colour, moisture, or composition can affect polymerisation, intrinsic viscosity, preform quality, bottle strength, haze, and the behaviour of thermoformed sheet.

Food contact applications create a further evidence burden, even when the recovered monomers are chemically equivalent to fossil derived inputs. Customers will require analytical data, traceability, process controls, contamination testing, and regulatory documentation before introducing the material into bottles, trays, or films used around food.

Further down the value chain, Plastipak’s pakPET resin places 30% post-consumer recycled material into a ready to use pellet intended to simplify processing for converters. DePoly is operating further upstream, widening the range of waste streams capable of returning to resin manufacture.

The two developments expose different pressure points inside PET circularity. Packaging plants need predictable resin that can run without creating scrap or quality variation, while recyclers need sufficient suitable feedstock to manufacture that resin economically and continuously.

DePoly estimates that production from the showcase facility can reduce emissions by up to 75% compared with virgin purified terephthalic acid when avoided incineration is included. As throughput rises, electricity sources, chemical recovery, yield, transport distances, and plant utilisation will determine how closely commercial output matches that assessment.

Feedstock supply could become the greater constraint if several chemical recycling plants move into operation simultaneously. Material currently regarded as residual waste may acquire greater value, increasing competition between mechanical recyclers, depolymerisation plants, textile recovery businesses, and energy from waste operators.

Contracts will therefore need detailed contamination limits and sampling procedures. A plant designed to process difficult waste still requires a controlled input specification, because excessive PVC, metals, moisture, food residue, or unrelated polymers can reduce yield and increase purification or disposal costs.

The Monthey site closes part of the gap between laboratory samples and commercial supply, allowing difficult feedstocks to reveal their operational consequences across tonnes rather than kilograms. It also gives customers enough material to test polymerisation, sheet extrusion, preform manufacture, and packaging performance under representative conditions.

Commercial viability will depend on whether the process retains its speed, purity, and energy performance at 100 times the current capacity. If those results survive scale-up, DePoly could provide another route for recovering PET packaging that currently falls outside the highest value recycling loop.