Environmental award for waste recycling project
SCOTTISH Sea Farms has won an environmental award for its work in recycling hatchery waste into nutrient-rich agricultural fertiliser.
The company was presented with a VIBES Scottish Environment Business Award in December, as part of an initiative that recognises work by Scottish-based businesses to adapt their way of working, products or services as a consequence of Covid-19 or have continued to progress low carbon opportunities despite the pandemic.
Scottish Sea Farms was praised by the award organisers for its work to capture fish waste from its new salmon hatchery at Barcaldine, near Oban, and recycle it as fertiliser to enrich farmland.
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 ambition to be net zero by 2045.
As part of the hatchery’s recirculating aquaculture system (RAS), any waste material, such as fish faeces or uneaten feed, is removed and captured for recycling.
Lead Engineer for Barcaldine RAS Hatchery, Ewen Leslie, explained: “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 sludgelike consistency, are then collected in a storage tank.”
Invergordon-based waste management company Rock Highland, part of the Avanti Environmental Group, then ensures the sludge is both safe and suitable for agricultural land. Rock Highland started out finding uses for waste from whisky distilleries and is now applying the same technique to fish farming.
Scottish Sea Farms’ freshwater team are now developing phase two of their fish waste recycling plans, with the goal of removing the remaining water content and converting the sludge into dry pellets.
“The benefit to the environment of moving from wet to dry form longer-term would be a reduction in the volume of waste material, thereby reducing the number of tankers and road miles required to transport it from hatchery to farmland,” said Ewen Leslie.
“For land farmers, dry form would provide an even more nutritional and valuable natural fertiliser alternative that’s easy to handle.”