Scottish Sea Farms, which operates along the west coast and in Orkney and Shetland, has won the VIBES Scottish Environment Business Award for the pioneering recycling scheme at its new £58 million salmon hatchery at Barcaldine, near Oban.
The firm has set up an innovative recirculating aquaculture system (RAS) which ensures the fish have a continuous supply of clean, oxygenated water that’s maintained at a steady temperature throughout the growing process.
During the ongoing cycle of cleaning and recirculating water, waste material such as fish faeces or uneaten feed is removed and captured for recycling.
The project is part of the company’s drive to set a new benchmark for sustainability in the sector and contribute to the Scottish Government’s climate goal for the country to reach net-zero emissions by 2045.
Ewen Leslie, lead engineer for Barcaldine RAS Hatchery, explained how the system works.
He said: “Using technology by Norwegian engineering company Scanship AS, we first aerate the waste to prevent any unwanted bacteria from germinating, then we bind it together into larger particles via the addition of a cationic polymer.
“That done, the waste is filtered to separate the solids from the water.
“These solids, which are now of a sludge-like consistency, are then collected in a storage tank.”Invergordon-based waste management company Rock Highland, part of the Avanti Environmental Group, ensures the nutrient-rich sludge is both safe and suitable for agricultural land before it is transported to farms.