Top marks for plastic bottle recycling system

An EU-funded project developed new plastic bottle marking, identification and sorting technology, facilitating the separation and reuse of packaging that has been used for food and drink.

Plastic waste is a growing problem for our environment and society. The EU alone produces around 322 million tonnes of plastic a year, about 60 % of which is used in packaging and consumer goods. Despite growing plastic waste collection, only 30 % of plastic is recycled in Europe – the rest goes to landfill or is incinerated.

EU regulations preventing recycled plastic previously used for non-food packaging from being used as food or drink packaging in its second life are one of the factors hindering recycling. The rules require recyclable plastic waste to be meticulously sorted into food and non-food packaging before it can be recycled for new food and drink packaging products – a process which is currently very rarely used, meaning that most food and drink packaging uses virgin plastics.

The EU-funded POLYMARK project set out to boost the recycling of certain categories of plastic with an innovative marking and sensor-based sorting system which easily identifies plastic previously used for food and drink packaging.

‘Our system is 98 % efficient. We believe that sensor-based sorting technology is key to enabling a circular economy for plastics,’ says POLYMARK project coordinator Estela Izquierdo from trade association European Plastic Converters.

Giving plastic bottles a second life

The project focused on polyethylene terephthalate (PET), a high-value thermoplastic polymer resin widely used in containers for liquids and foods, like mineral water bottles. Although it is easily recycled into materials such as carpet fibre, its reuse could be expanded thanks to a new system to identify plastics previously used in food and drink packaging.

As a first step, POLYMARK scientists created a food and drink container marking and identification system. During manufacture, plastics used for food and drink can be coated with a chemical marker, or the marker can be applied to the product label. The marker does not change the appearance of the packaging but can be detected using optical technology.

Next, researchers developed a machine to detect the marked plastics. Plastic bottles and containers pass through a marker-detection unit before being separated into those that have been used for food and drink and those that have not. The detection system uses ultraviolet light and sensitive cameras that can pick up the fluorescent signal in the chemical marker.

The containers identified as food and drink packaging can then be cleaned in normal recycling washing facilities – a process that also removes the marker.

Seeking an industry-supported vision

The technology has been developed and is market-ready. Project partners are now participating in a cross-industry platform seeking to harmonise the use of tracer and watermark technologies in the plastic-packaging value chain.

‘Following the successful development of POLYMARK technology, partners are aiming to develop an industry-supported vision to align on a single global standard or at least a handful of compatible standards for tracer- or marker-based sorting,’ explains Izquierdo.

The project initially focused on PET plastics but is aiming to expand to other polymers to ease the sorting process and improve recycling rates. As part of the EU’s circular economy, this will provide a much-needed boost for the environment, European consumers and industry alike.