New camera technology could revolutionize the recycling of plastic materials

Today, plastic is difficult to recycle because plastic waste is a mishmash of many different polymer types with different chemical compositions, as well as fillers such as, e.g. dyes, flame retardants and other additives that give a plastic product its specific properties.

With 7.9 million DKK in funding from the Innovation Fund's Grand Solutions program (total budget of DKK 11.3 million), Aarhus University (AU), University of Southern Denmark (SDU) and the company Newtec Engineering A/S have started a project to develop a unique camera technology that can make it easier to recycle plastic materials.

The goal is to create a high-resolution hyperspectral camera with a spectral range from about 400 nm to 1,900 nm with a desired resolution of only 2 nm.

"It is a very ambitious goal for this technology, and it places strict demands on the optical components of the camera technology. At the same time, as a unique high resolution, we are working to optimize the camera optics for light spectra that are central to the plastic analysis. We solve this part in collaboration with leading experts in optics at the University of Southern Denmark and Newtec, which is unique in camera development," says associate professor Mogens Hinge from Aarhus University's Department of Bio- and Chemical Technology.

Associate Professor René Lynge Eriksen from SDU NanoSYD is at the forefront of the optics development in the super-high-resolution hyperspectral camera, which will be used to detect the chemical composition of plastic waste.

"We have to work with optics and sensors that cover a large spectral range, both visible and infrared light - which to that extent, excitingly, challenges traditional design and the composition of optical components," says René Lynge Eriksen.

Mogens Hinge and the research group Plastics and Polymer Engineering, which leads the project, have previously proven that hyperspectral camera technology can revolutionize the recycling of plastics. And the higher the resolution and the more comprehensive the spectral range the hyperspectral camera has, the better.

The goal of the new project, which goes by the name New Hyperspectral Camera Technology for material identification, NewHC, is a spectral resolution and range that is so high that the camera can reveal, for example, unwanted fire retardants and pigments in the plastic that may be prohibited or harmful, so that they can be removed before reuse.

"We must sort plastic into as pure fractions as possible to increase the degree of recycling. Today, purities of at least 95 per cent are required in the plastic bits, preferably higher. And it is precisely fast and efficient plastic recognition that we aim to automate with this technology. In this way, we can push the boundaries for future recycling of plastic waste so that the need to make new plastic is reduced," says Bjarke Jørgensen, Head of Research & Development at Newtec Engineering A/S.

The new camera technology is being developed by the research group Plastics and Polymer Engineering (AU), NanoSYD (SDU), which is internationally recognized for research in optics, and Newtec Engineering A/S, which is a market-leading machine manufacturer specializing in advanced camera technology. And when the technology is developed, it is installed in specially designed waste sorting facilities in collaboration with Newtec Engineering A/S.

Facts
The project has a total budget of DKK 11.3 million. DKK and runs over three years. The Innovation Fund's investment is DKK 7.9 million. DKK THE FACTS A study published in Science Advances in 2017 shows that only 9% of the total 8.3 billion tonnes of plastic waste produced since the 1950s has been recycled.

Twelve per cent has been converted into energy via combustion, while almost 80 per cent are located in landfills or the wild. In Denmark, 31 per cent of the plastic that has been used for packaging is recycled. If you look at industrial packaging separately, recycling is 64 per cent, while plastic packaging from households is 15 per cent.

In 2015, Danes sorted 38,000 tonnes of packaging plastic from their waste. Danish homes accounted for 18,000 tonnes of plastic packaging, the service sector for 10,000 tonnes, and industry for 8,000 tonnes. The last 2,000 tonnes came, among other things, from agriculture.

Source: Danish Environmental Protection Agency, PlasticsEurope Hyperspectral imaging is an advanced camera technique where you record images with many more specific colour channels than a regular RGB camera with only 3 (red, green and blue).