Circular bioeconomy concept of aquaculture

The goal of Finnish aquaculture strategy is to triple the production of fish farming from approximately 8.5 million kilograms to 25 million kilograms without jeopardizing the water and marine management goals. Recirculating aquaculture systems (RAS) are one way to increase the production of fish farming, as the method enables the removal or recovery of nutrients, so that the water management goals can be achieved. However, there are challenges in RAS, as economic profitability is weak and full production volumes have not been reached. In the current state, RAS farms mainly remove nutrients, but nutrient recovery could add value to production and improve economic profitability.

In the circular bioeconomy concept of aquaculture (KiertoKala) project, the side streams of a mega-size RAS farms (500–5000 tn) are calculated, and the techniques and methods suitable for their utilization are determined. The best methods for the recovery of soluble phosphorus and soluble nitrogen are being piloted in the Natural Resources Institute Finland (Luke) Laukaa RAS research platform, and their suitability as recycled nutrients is being investigated. The suitability of fish sludge for biogas production is also being piloted in the RAS platform. In addition to these, the utilization of cutting waste is investigated using literature and available equipment. Potential areas of operation and actors utilizing the side streams are mapped in the Central Finland region. In addition to this, the project and the business potentials it brings out are discussed with companies but also at various events in the industry.

Based on calculation, piloting and mapping, a circular economy concept suitable for RAS production is created, where all side streams will be utilized either as new products, nutrients or energy. The goal is to enable profitable and environmentally friendly fish farming, to improve material efficiency and to create new jobs and operators to utilize the side streams of fish farming. The final output of the project is a written report that compiles the results of the different work packages.