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Water & wastewater
Water & wastewaterWastewater treatment plant upgrade, storm water storage, water quality improvement

Millbrook Wastewater Treatment Works Upgrade

Southampton · Ongoing (Final stage reached November 2023, completion expected soon after) [Water Magazine, Daily Echo] · £25m [Water Magazine, Daily Echo]

The judgement call

Account-gated at launch

Focus on improving water quality in Southampton Water and protecting shellfish [Water Projects Online] - Investment in advanced treatment processes like UV to meet environmental standards [Daily Echo]

Key engineering challenges

Protecting and enhancing Southampton Water [Water Magazine] - Increasing stormwater storage capacity to reduce pollution incidents [Daily Echo] - Implementing new treatment processes like UV to improve water quality [Daily Echo] - Delivering upgrades on a live treatment site [LinkedIn (general challenge for Whitlingham, but applicable here)]

Project facts

Client / owner
Southern Water
Lead contractor
GTb (Galliford Try Environment and Binnies UK Ltd) [WaterHQ.world]
Lead designers
Project type
upgrade
Scale
Doubled stormwater storage capacity [Daily Echo]; Equipped with new ultraviolet treatment process [Daily Echo]
Disciplines
Civil; process; environmental; mechanical; electrical
Standards & frameworks
Environmental Agency regulations

Sources: Water Magazine: https://www.watermagazine.co.uk/2023/11/09/southern-water-enters-final-stage-of-major-25m-project-in-southampton/ (Accessed: 2026-06-10) - Daily Echo: https://www.dailyecho.co.uk/news/23879154.southern-water-nears-end-millbrook-sewage-works-upgrade/ (Accessed: 2026-06-10) - Water Projects Online: https://waterprojectsonline.com/case-studies/southampton-shellfish-scheme-2024/ (Accessed: 2026-06-10) - WaterHQ.world: https://waterhq.world/issue-sections/wastewater-treatment/wastewater-treatment/southampton-wastewater-treatment-works-upgrade-enhances-water-quality/ (Accessed: 2026-06-10)