Small hydro |
Left, top to bottom: Bespoke ‘Y’ piece in situ showing bypass and manual isolation valves
Control panel for turbine CINK Crossflow turbine installed onsite Containerised turbine off site
effluent, reducing the amount of air needed in the aeration tanks, thereby further decreasing the energy demand of the treatment process.
Selecting the right turbine technology Given the variable flow rates at Hamilton WwTW,
which fluctuate between 300 and 1,200 litres per second due to weather and waste water loads, selecting the right turbine was critical. After careful evaluation, a Crossflow turbine from CINK Hydro- Energy was chosen for its ability to maintain efficiency across a wide range of flow conditions. The turbine is well-suited to waste water applications as it features a self-cleaning mechanism that reduces the risk of clogging from fine particles in the effluent. A bleed valve was integrated at the pipework inlet
to divert excess flow, ensuring continuous power generation even during exceptionally high flow conditions.
Beaumont said: “The Crossflow was the ideal choice because of its resilience in waste water environments and its ability to handle fluctuating flow rates efficiently. As the turbine has only three moving parts, it is an incredibly robust technology that ensures long term reliability with minimal maintenance.” The turbine harnesses energy from waste water after it has undergone several treatment stages, including screening, grit removal, and aeration. At this point, the effluent contains reactivated sludge, which is denser than fully treated effluent and may enhance turbine power output. To mitigate potential impacts from fine particles, turbine selection and design modifications were implemented.
Construction and installation process The construction phase began in April 2023, with
the removal of the existing flume in May. A temporary flume was installed to allow effluent to bypass the work area, minimising risks to workers. Following this, concrete sub-structures and tail-race works were completed to accommodate the turbine housing. The existing pipework was retrofitted with a custom- designed ‘Y’ section, incorporating bypass and bleed valves to optimise flow management. A level sensor installed at the aeration tank outlet communicates with the turbine control system, adjusting the valves and turbine guide vanes to match flow conditions. A key innovation in the project was the use of a pre-
fabricated, containerised turbine house. Assembled off-site by CINK Hydro-Energy, this approach significantly reduced carbon emissions associated with construction and minimised time on-site. Once delivered, the container was crane-lifted into position, pipework was connected, and testing commenced. The turbine control system was calibrated to adjust automatically to varying flow conditions, ensuring optimal performance. The system was connected to
22 | March 2025 |
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the grid in November 2023 and has been generating renewable electricity since.
The future of small-scale hydropower
in Scotland The Hamilton hydropower project is estimated to generate 420,000 kWh of renewable electricity annually, offsetting approximately 14% of the site’s energy demand and saving around 64 tonnes of carbon emissions each year. This success underscores the potential for further hydropower opportunities across Scottish Water’s extensive network. Beaumont added: “This project has proven that small-scale hydropower can be a valuable addition to waste water treatment sites. We’re now looking at how we can replicate this model at other locations to further support Scottish Water’s sustainability goals.” The success of the containerised approach at
Hamilton provides a blueprint for rapid deployment, reducing both capital expenditure and environmental impact. There is also scope to extend this concept beyond waste water assets, exploring applications in raw water treatment, industrial effluent management, and other sectors where significant water flows are present.
A collaborative effort The success of the Hamilton hydropower scheme was
made possible through close collaboration between Scottish Water Horizons and its supply chain partners. Key contributors included: FES Support Services Ltd - Design and project delivery Glen Hydro - Specialist hydro consultant Calforth Construction Ltd - Civil works Dustacco Engineering Ltd - Mechanical installation CINK Hydro-Energy k.s. - Turbine supplier Glenfield Invicta - Valve supplier
The project highlights the importance of innovation, collaboration, and data-driven decision-making in advancing Scotland’s renewable energy transition.
Conclusion From initial concept to site commencement, the
Hamilton hydropower project took approximately 21 months to deliver. This demonstrates the efficiency of the containerised approach, paving the way for faster delivery of future similar projects. Piggott said: “We’re incredibly proud of what we’ve achieved at Hamilton. This project showcases what can be done when innovation and collaboration come together to deliver real, tangible benefits for sustainability.” The project stands as a testament to Scottish Water
Horizons’ commitment to decarbonising waste water treatment operations. As the company continues to explore and implement renewable energy solutions, the lessons learned from Hamilton will inform future projects, ensuring Scotland remains at the forefront of water industry decarbonisation.
Author information
Neil Beaumont - Senior Project Manager; Ian Piggott - Senior Project Manager; Stuart Clark - Project Manager; and Steven Brasher - Specialist Graduate
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