The MSWPlast project, a co-research initiative within the SPIRIT ecosystem, concluded in April 2025 after two years of intensive research and collaboration. Led by VTT Technical Research Centre of Finland, the project deepened the understanding of recycling plastics from residual municipal solid waste (MSW). By developing a technical concept for pre-treatment and recycling and a systemic model for integrating post-sorting into existing recycling value chains, the project has revealed promising pathways for tackling the challenge of recycling plastic waste, which currently is incinerated.
Addressing the problem of mixed waste plastics
The low recycling rate of plastic waste is a persistent challenge, and residual MSW contains significant quantities of recyclable plastics that are currently incinerated. The MSWPlast project focused on high-value plastic materials such as polyolefins, which are widely used in packaging and consumer goods.
Senior scientist Malin zu Castell-Rüdenhausen from VTT, the project’s coordinator, highlighted the critical need to utilise these materials more efficiently. “These plastics are valuable resources that should not be wasted through incineration. Instead, they can be recycled into new, high-quality products, contributing to a circular economy,” she explained. In the co-research project, VTT brought to the table their technical expertise and the Finnish Environment Institute (Syke), represented by senior researcher Hanna Salmenperä, provided regulatory and societal insights on the matter.
The MSWPlast project set out with ambitious goals, including:
- Proving the feasibility of separating plastics from mixed waste for recycling into high-value products.
- Encouraging informed discussions about the role of residual MSW sorting versus separate collection systems.
- Exploring the broader implications of these systems for incineration practices, recycling rates and policy frameworks.
- The project aimed to answer critical questions, many of which are hotly debated within the waste management sector and among citizens: Can plastics realistically be separated from residual MSW at scale? Is separate collection sufficient to meet recycling targets, or is mixed waste sorting necessary? How do these approaches compare to incineration in terms of energy efficiency and material recovery?
Sorting trials and key findings
One of the elements in the project was a sorting trial, which processed 500 tonnes of residual MSW to assess the feasibility of extracting plastics for recycling. Over 300 tonnes of this waste was sent to Remeo’s sorting plant in Vantaa, Finland, where advanced industrial sorting technologies were deployed to sort out the wanted plastics fractions. Remeo was one of the industrial partners in this project. The trial generated a lot of data and material samples, which were subsequently analysed to model the efficiency and recyclability of the sorted materials.
The extracted plastics were washed in the Netherlands, as Finland currently lacks the necessary pilot infrastructure for plastic waste washing. Using the washed materials, VTT successfully produced plastic pellets and stretched films, demonstrating that these materials could be recycled into high-quality products.
Insights from system modelling and plant visits
The study revealed that, in the most advanced European facilities, up to 70-90% of plastics in mixed waste can be separated and recycled. However, the study also highlighted the impact of contamination — particularly from organic waste — on the recyclability of plastics. This highlights the importance of efficient biowaste collection systems to reduce contamination and improve recycling yields.
Using the data collected during the sorting trial, the project team developed models to evaluate the yield and efficiency of sorting facilities. These developed models are able to predict the key factors such as the performance of optical sorting technologies and the proportion of plastics that could be recovered from mixed waste streams. The findings provide valuable insights for designing more efficient sorting systems and estimating their potential contributions to national recycling targets.
The team also conducted visits to sorting plants in Finland, the Netherlands, Norway and Sweden to get deeper understanding of the technical and economic performance of different sorting facilities. For example, the Netherlands stands out for its advanced mixed waste sorting technologies, while Finland’s smaller-scale facilities illustrate the need for further investment in modern infrastructure.
The study found that the profitability of sorting plants varies significantly depending on the operating model. In some countries, sorting plants own the materials they process, while in others they only provide a service. Also gate fees and producer responsibilities play a large role in financing the sorting of residual MSW. Therefore, tailored solutions that consider the unique circumstances of each country are clearly needed.
Policy implications and lessons learned
Policy and regulation were central to the project’s scope. Hanna Salmenperä explained that while there are no direct regulatory obstacles to industrial-scale sorting of mixed waste in Finland, the policy framework remains complex and is subject to ongoing changes. “Waste management is a highly regulated sector, and new requirements for recycling targets and emissions are constantly being introduced. This creates both challenges and opportunities for innovation,” she noted.
The project also explored policy models from other European countries. For instance, the Netherlands employs advanced eco-modulated producer responsibility fees, which incentivise manufacturers to use recyclable materials. Such mechanisms could be developed for Finland to encourage more sustainable practices across the value chain.
In Finland, separate collection of waste is mandatory, and cannot be abandoned. However, the team proposed a hybrid model that combines source-segregated collection with industrial-scale sorting of mixed waste. Such a model could maximise resource recovery while addressing the limitations of each approach.
Challenges and opportunities for future research
Areas for further research and development were also identified. Contamination of plastics with organic waste remains a major challenge for the efficiency of the sorting plants. Improving biowaste collection systems and public awareness will be critical to enable post-sorting of residual MSW.
Another challenge lies in public communication. Educating citizens about the role of on- site sorting and post-sorting is essential for gaining public support and ensuring the success of new waste management systems. There is also a need for further research to enhance the efficiency of separate collection systems and to explore the economic viability of scaling up industrial sorting technologies.
There is active discussion of the possibilities of residual MSW sorting in Finland now. Jaakko Tuomainen, SPIRIT programme manager, is very satisfied how the SPIRIT programme can now contribute to this discussion: “It is great that we kicked off the MSWPlast project some years ago. The researchers can now bring scientific results into the considerations, what could be the role of MSW sorting in Finland in the future.”
The MSWPlast project demonstrated that plastics can be effectively separated from mixed waste and recycled into valuable products, offering a viable alternative to incineration. As Finland and other countries work towards meeting their recycling targets, the findings from MSWPlast will serve as a valuable resource. With the right investments in infrastructure, technology and policy, the potential to recover valuable plastics from mixed waste streams could be fully realised.
Photo credit: Remeo.
In addition to Borealis, the other industrial partners in MSWPlast project were:
Remeo: https://remeo.fi/kiertotalous/tutustu-moderniin-kierratyslaitokseemme/
Vantaa Energy: https://www.vantaanenergia.fi/tietoa-meista/hankkeet/lajittelulaitos/