Posted by Administrator
Scottish Sea Farms’ pioneering work to recycle hatchery waste into nutrient-rich agricultural fertiliser has been recognised with a VIBES Scottish Environment Business Award.
The VIBES invited businesses this year to share their stories of how they have adapted 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, which operates along the west coast of Scotland and in the Northern Isles, was praised by the award organisers for its work to capture fish waste from its new £58 million 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.
Throughout the growing process, the hatchery’s innovative recirculating aquaculture system (RAS) ensures that the fish have a continuous supply of clean, oxygenated water that’s maintained at a steady temperature.
During this same ongoing cycle of cleaning and recirculating water, 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 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 sludge is both safe and suitable for agricultural land.
Rock Highland Divisional Director Neil Barker said: ‘We first started out by working with one or two of Scotland’s whisky distillers, helping recycle nutrient-bearing effluent originating from barley into fertiliser.
‘Over 15 years later, we’re now working with distilleries from the Orkney Islands all the way down to the Central Belt, spreading around 175,000 tonnes of distillery effluent per annum back to the land via a network of registered landbanks across the whole of Scotland.
‘Recent years have seen us diversify and apply the same sustainable service to Scotland’s salmon farmers, with our proven model now collecting sludge from most of the salmon hatcheries across the Highlands and islands of Scotland.’
Responsible for bringing the two companies together was Northern Light Consulting which project managed the new hatchery from feasibility study through the final construction.
Northern Light Consulting Director Sarah Riddle said: ‘After working closely with Scottish Sea Farms to investigate every viable option to deal with the hatchery waste sludge, we were delighted to recommend Rock Highland’s sustainable back-to-land solution.
‘As the aquaculture industry continues to work hard to reduce its environmental impact, new opportunities arise and we look forward to working together on innovative solutions towards achieving zero waste.’
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.’
As a primary food producer, Scottish Sea Farms has continued to operate throughout the Covid-19 pandemic, adapting shift patterns at its farms and introducing social distancing precautions at all workplaces, including on shore, helping to safeguard job security for people living in the remote areas of the UK.