Waste management
Waste not, want not
One person’s disposal problem could be another’s valuable resource
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ealing with waste can be a major issue for all aspects of aquaculture. Waste – whether in the form of fish faeces, uneaten food or dead fish – represents not only a cost for farmers but also an important part of a farming operation’s environmental footprint. Fortunately, with the right approach even waste that appears to be nothing but a problem can become a resource with value in its own right. One example is the Outer Hebrides Local Energy Hub (OHLEH), which brings together local energy suppliers with the Scottish Salmon Company (SSC) to recycle fish waste, including trimmings. The project involves the transfer of waste from SSC’s processing plant on the Isle of Lewis, which is integrated with other local household and garden waste to produce biogas in an anaerobic digester at the CnES Household Waste and Recycling Centre in Creed.The biogas fuels a Combined Heat and Power plant, with some of the electricity generated used to drive an electrolyser which in turn produces hydrogen and oxygen for use at SSC’s hatchery in Lewis, as well as providing fuel for CnES’s hydrogen-powered bin lorry. (OHLEH) is a multi-sector partnership comprising the SSC, Pure Energy Centre, Community Energy Scotland, and Comhairle nan Eilean Siar (CnES). It was created with support from Local Energy Scotland through the Scottish Government’s Local Energy Challenge Fund.This project was the first of its kind in Scotland and was included on the shortlist for a VIBES Partnership Scotland Award – which recognises environment achievements – in 2019. Scottish Sea Farms’ hatchery at Barcaldine, meanwhile, not only uses energy from a biomass energy system using locally sourced woodchips, but also recycles fish waste (primarily faeces or any uneaten feed) for repurposing as nutrient-rich agricultural fertiliser to aid crop development. Both of these are examples of the “circular economy” concept, in which waste or by-product from one process is used as a resource in another process. Norwegian company Bluecirc – formerly known as Greenshore – specialises in processing waste from fish farming, including sludge, trimmings and morts
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Waste that appears to be nothing but a problem can become a resource with value
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(dead fish). As well as helping farmers to dispose of waste, Bluecirc is focused on finding ways to process it so that it can be reused. The company’s treatment for sludge is already in operation, and it is now also developing a solution for processing morts. Its aim is to replace the typical acid-based disposal process with an alternative system in which the fish waste is ground and then dried to become a useable product, for example in agricultural fertiliser. As the company puts it:“Everyone who handles acid treatment at a fish farm knows what we were talking about. It’s a job no one really wants… a system based on drying is safer, cheaper and easier.” The new process is subject to European Union approval, and is scheduled to be launched some time next year. Collecting waste from a hatchery or RAS (recirculating aquaculture system) plant is one thing, but
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12/10/2021 15:40:34
