Circular synergies between land and sea

Fish sludge from the Norwegian fishing industry is rich in nitrogen and phosphorus, substances that are currently being lost to the sea. This not only wastes valuable resources, but also has a negative impact on the marine ecosystem. At the same time, there is a shortage of phosphorus and nitrogen in both Swedish and Norwegian agriculture, where these substances could be used as natural fertilisers to increase agricultural productivity and reduce dependence on artificial fertilisers. There is currently no obligation to collect fish sludge in Norway, but fish sludge has the potential to become the Nordic region's bio-based fertiliser for growing protein-rich crops, for livestock and as a possible protein source for fish feed, which would fully recycle the nutrients.

The Circular Land-Sea Synergies project is now exploring the potential to transform this residual flow and work towards more circular production, which in turn will contribute to increased competitiveness and self-sufficiency. In close and cross-border collaboration with new and existing industrial environments, the project will gather experience and data to create new and more sustainable value chains. The collaboration will contribute to the blue-green transition and circular economy in the fisheries sector.

However, fish sludge is a wet and heavy mass, making it difficult to transport and logistically challenging to use in agriculture. To overcome these challenges, technical solutions are needed to collect, process and transport fish sludge in an efficient and economically sustainable manner.

The project aims to:

• Improve the knowledge of decision-makers to make sustainable, circular and sector-relevant decisions about facilities that promote industrial symbiosis.
• develop a techno-economic and life cycle analysis for the use of fish sludge.
• Conduct crop trials with fish sludge as a soil conditioner.
• Liaise for resource-efficient bio-economic development of industrial symbioses in Sweden and Norway.

RISE's role in the project

The Circular synergies between land and sea project is coordinated by RISE. We are also carrying out tests on sludge from sea and land-based fish farms using hydrothermal carbonisation (HTC) to carbonise the sludge, which will then be tested through plant cultivation trials at Torsta in Krokom and Val skoler in Rörvik. Together with the High Coast Innovation Park site and the potential sites Kråköga in Rörvik and Alby in Ånge, we are carrying out techno-economic and life-cycle analyses for the exchange of knowledge and experience between Swedish and Norwegian industrial parks for industrial symbiosis.