Scottish Water is seeking feedback on its plans to rebuild the Daldowie bioresource facility near Glasgow — but the consultation is only the latest step in a far more ambitious story: one of the largest infrastructure investments in Scottish Water's history, and a project with serious implications for Scotland's climate targets.
The Daldowie site is Scottish Water's preferred location for the new facility, which would treat bioresource from Greater Glasgow and Central Scotland with a projected average throughput to 2040 of 85,000 tonnes of dry solids per year. The site has operated under a Private Finance Initiative (PFI) contract since the early 2000s, thermally drying sludge using natural gas. That arrangement is ending after 25 years, and Scottish Water is taking the facility back into public ownership along with a major investment to replace what it describes as ageing, energy-intensive infrastructure.
From gas-fired dryers to biogas and biomethane
The new facility would work very differently. Scottish Water plans to use thermal hydrolysis to treat the bioresource and prepare it for anaerobic digestion, a biological process that takes place in enclosed tanks, with technology supplied by Cambi. That process produces biogas, which can generate heat and electricity for the plant, or be upgraded to biomethane and exported to the national gas grid, displacing fossil fuels. The treated solid residue (biosolids) would be applied to farmland as organic fertiliser under licence, a practice supported by SEPA.
That biogas can generate heat and electricity for the plant itself, or be upgraded to biomethane and fed into the national gas grid, displacing fossil fuels. The treated solid residue (biosolids) would be applied to farmland as organic fertiliser under licence — a practice supported by the Scottish Environment Protection Agency (SEPA).
The carbon and cost case
The carbon case is striking. The existing facility generates around 40,000 tonnes of CO₂ per year, and the new centre would cut that by approximately 30,000 tonnes annually, which Scottish Water describes as a "substantial contribution" to its commitment to reach net zero by 2040, five years ahead of Scotland's national target.
The financial scale matches the ambition. The estimated project value is in the range of £265 million to £415 million at 2024 prices, with a planned construction start date of April 2027, according to the official tender notice. The contract has not yet been awarded — Scottish Water is currently in an Early Contractor Involvement phase, working with shortlisted firms to develop the design before a final build contract is signed. A planning application is expected later this year, once Scottish Water has carried out significant engagement with customers and key stakeholders.
