Finnish research sets out to dig up plastic from mixed waste

The two-year project is expected to enhance knowledge of the recyclability of plastics in mixed waste and create concepts for waste processing and introducing post-sorting recycling capabilities to existing recycling value chains.

The project partners will carry out a pilot at the sorting facility of Remeo in Vantaa. In the pilot, 500 tonnes of mixed waste from households and businesses will be sorted and analysed to produce insights on the feasibility of sorting mixed waste on an industrial scale.

Plastics accounted for an estimated 16.6 per cent, or 288 000 tonnes, of mixed municipal waste collected in Finland in 2019, a total that far exceeds the 74 500 tonnes of plastic waste collected separately. Data from Statistics Finland indicate that almost 99 per cent of the mixed waste and 25 per cent of separately collected plastic waste was incinerated to generate energy in 2019.

Because the incineration of mixed waste emits carbon dioxide, separating plastics from mixed waste would reduce emissions but also create business opportunities and reduce the need to import raw materials for plastic production, according to VTT.

“Plastics in household waste are evidently highly mixed and contain contaminants and difficult-to-recycle multilayer packaging plastics, and it can be challenging to separate pure enough raw material for mechanical recycling,” stated Mika Härkönen, professor of practice at VTT.

“Therefore, the plastics separated from municipal solid waste may offer a highly interesting feedstock source for chemical recycling, providing [a] route to production of high-quality recycled plastics.”

Hanna Salmenperä, senior adviser at the Finnish Environment Institute (Syke), reminded that the European Commission recently warned Finland that it is not on track to achieve its 55-per cent recycling target for 2025.

The recycling rate in the country stood at 39 per cent in 2021.

“The main reasons for low recycling performance are low capture rates of separately collected waste and the strong role of waste incineration,” she summarised. “We need to look closer at all possible practices to enhance […] material cycles.”

Also Borealis and Vantaa Energy are participating in the project funded by Business Finland.

Scientists at VTT are also developing enzyme-based methods for breaking down and converting plastic waste into biodegradable materials, such as fatty acids.