Bakkafrost Scotland is set to boost its circular economy credentials at its flagship recirculating aquaculture system (RAS) facility at Applecross with a new cutting-edge treatment system that turns the byproduct into fertilizer.

Scottish Environmental Protection Agency (SEPA) has granted the first Waste Management Licence in Scotland for a hatchery pyrolysis unit and Bakkafrost Scotland will build a new treatment system to create biochar from surplus produced at the RAS facility.

The surplus is a byproduct of the wastewater treatment process, consisting of organic and inorganic solids held in water. The process dries the sludge and turns it into inert biochar which is known as a fertilizer and soil improver, refining the structure and water retention in soils. This process also “locks away” carbon permanently.

In the first stage, hatchery sludge, roughly 97% water, is treated by going through a filter belt. The water content is reduced to about 80% and the dry matter content is increased to about 20%.

The next stage requires the license as it incorporates a pyrolysis unit that dries sludge at about 300°C, generating sludge pellets. These are then heated to 700°C without the presence of oxygen during a pyrolysis process. Heat is effectively absorbed and repurposed inside the system, increasing total energy efficiency. The end product is a biochar which is a material with a highly stable carbon content.

“In a RAS facility, substantial quantities of unused ‘waste’ materials are generated, which must be separated from the water circulating back to the fish. Traditionally, that material has been considered waste, but technological advancements have opened the door to a more sustainable management process and that must be good news for helping protect our environment,” said Ian Laister, managing director at Bakkafrost Scotland. “All of this is very much in line with Bakkafrost Scotland’s sustainability goals and supports building a circular economy from farm to fork.”

The new project aligns with Bakkafrost Scotland’s commitment to play a leading role in the sustainable transformation of the aquaculture industry to ensure it is fit for the future with a significant investment program over the next ten years and designed to strengthen, grow, and transform the business.

Bakkafrost Scotland’s ambition for its RAS facilities is to reduce waste by 90%, use 100% sustainable power and reduce the water used in the process by 90%. Hydro, solar, recycled material, and heat recovery systems will be used to reduce impact on the environment.