The focus of the project is materials that are difficult to treat, such as sewage sludge containing microplastic and metal contaminants, as well as many other problematic components.
– Sweden has invested heavily in infrastructure to treat organic waste such as sewage sludge. Today, biological methods are used, such as composting and digestion, or thermal methods such as combustion, gasification and pyrolysis. But the biological and thermal methods have been developed in parallel, thus losing the efficiency improvements achieved by combining the benefits of different methods, says Elisabeth Wetterlund, Associate professor of Energy Engineering at Luleå University of Technology, and she further points out:
– There is a great potential for improvement if combined waste treatment can be implemented and such solutions are developed in the project together with relevant companies.
Application in focus
Work on improving waste management takes place in several projects in different areas at Luleå University of Technology. Through collaboration between research groups in Waste Science and Technology and Energy Engineering, a unique competence in the area at a national level has been built up. Researchers Marcus Öhman, Professor of Energy Engineering, Anders Lagerkvist and Lale Andreas, Professor and Associate professor of Waste Science and Technology, have for many years performed research around these processes.
– In this project, we take another step to explore how to implement different types of integrated treatment systems, and what effects it can provide in a technical, economic, energy and environmental perspective. It relates to my previous research in techno-economic system analysis linked to biorefineries. This is a new area but with proven methods. We will also investigate obstacles and drivers at both the actor, company and policy levels to facilitate future implementation of the system, says Elisabeth Wetterlund.
– A user panel is now created to engage in dialogue with the industry. Several influential actors are already on board and we like to add a few more. Ideally, the project will generate spin-offs in the form of tests conducted in plants around the country, says Anders Lagerkvist.
Resources in waste
– Nutrients like nitrogen and phosphorus are examples of substances that are important to recycle, especially from a global perspective. Particularly phosphorus is a limited resource, as it is becoming increasingly difficult to find phosphor-minerals without high levels of hazardous substances such as, for example, cadmium. Our hypothesis is that by integrating thermal and biological processes, it is possible to increase both energy efficiency and the production of high-quality materials such as mineral phosphorus, says Marcus Öhman.
In addition to researchers at Luleå University of Technology, postdoctoral Björn Wallsten, previously employed at Linköping University, participates in the project.