November 14, 2023

Novel approach to aquaculture waste management in Scotland fuels circular growth

A new chemical-free method for treating aquaculture waste, led by researchers at the Scottish Association for Marine Science (SAMS) with support from the Sustainable Aquaculture Innovation Centre (SAIC), holds the potential to revolutionise waste management in the seafood industry, Fisker Forum reported.

Supported by Scottish Sea Farms, water technology supplier Power and Water, and waste services company Tradebe, the initiative aims to establish a circular model for co-products, presenting new opportunities for seafood producers.

Chief executive officer of SAIC, Heather Jones, highlighted the project's focus on addressing waste at its source and creating a viable circular model. The study, backed by collaborative efforts, aims to minimise the environmental impact of aquaculture while exploring higher-value commercial possibilities for co-products. Most notably, the research could lead to the repurposing of by-products within the farmed salmon sector, potentially serving as a protein-rich feed ingredient.

The project, conducted at Scottish Sea Farms' Barcaldine Hatchery near Oban, utilises water treatment equipment provided by Power and Water. Employing an electrochemical process and ultrasound technology, the system extracts excess water from waste material. The remaining nutrient-rich substance is then utilized to enhance the growth of marine worms (polychaetes). These worms are subsequently evaluated for their nutritional profile, including protein and fatty acids, to assess their suitability as feed ingredients for aquaculture.

The wastewater undergoes a second stage of filtration using natural seaweed to absorb nitrogen and phosphorous. The comprehensive approach to waste management seeks to demonstrate the value of aquaculture waste, turning it into a resource for sustainable feed ingredients and benefiting the sector as a whole.

Dr Georgina Robinson, lead researcher and UKRI Future Leaders Fellow at SAMS, emphasised the opportunities in exploring co-products that could change the perception of aquaculture waste. The circular approach envisions using co-products to support the growth of other organisms beneficial to the sector.

The final phase of the research involves an evaluation of the environmental impact and the mitigation of greenhouse gas emissions compared to existing waste disposal methods. Currently, liquid aquaculture waste is transported and spread to land in rural locations after treatment.

Ewen Leslie, head of Freshwater Engineering and Project Lead at Scottish Sea Farms, expressed optimism about the collaboration's potential to diversify and expand the range of by-products delivered. SAMS plans to bring this circular concept to market through a spinout called N-ovatio-N early next year, following Dr Robinson's recognition at The Converge Challenge in October.

-      Fisker Forum