Deephams Sewage Treatment Works Upgrade (A630 Major Upgrade)
Enfield, London · 2013-2019 (Upgrade between 2013 and 2019) [Ayesa Engineering]; Delivery date 2018 [EIC-UK] · £212m [ICE, EIC-UK]; £180m (contract value) [Construction News]
The judgement call
Account-gated at launchImproved final effluent quality discharged to the River Lee [WaterProjectsOnline] - Project achieved a 99% reduction in odour emissions [ICE] - Focus on environmental compliance and sustainability [River Lea Catchment]
Key engineering challenges
Meeting new, tighter Environment Agency wastewater standards [AECOM, Adams Hendry] - Increasing capacity to manage population growth in the catchment [WaterProjectsOnline, Adams Hendry] - Modernising and equipping the plant [AECOM] - Achieving a significant reduction in odour emissions [ICE, Adams Hendry]
Project facts
- Client / owner
- Thames Water
- Lead contractor
- AECOM, Murphy, Kier (Joint Venture - AMK) [AECOM, EIC-UK]
- Lead designers
- AECOM [AECOM]
- Project type
- upgrade
- Scale
- Accommodate 989,000 population equivalent [Ayesa Engineering]; 99% reduction in odour emissions [ICE]
- Disciplines
- Civil; process; environmental; mechanical; electrical
- Standards & frameworks
- Environment Agency wastewater standards; IChemE Burgundy book contract with NEC 3 additions [Construction News]
Sources: ICE: https://www.ice.org.uk/what-is-civil-engineering/infrastructure-projects/deephams-sewage-treatment-work-major-upgrade-project (Accessed: 2026-06-10) - WaterProjectsOnline: https://waterprojectsonline.com/case-studies/deephams-stw-2018/ (Accessed: 2026-06-10) - Ayesa Engineering: https://www.ayesa.com/en/projects/deephams-stw/ (Accessed: 2026-06-10) - AECOM: https://investors.aecom.com/news-releases/news-release-details/aecom-joint-venture-awarded-us2858-million-contract-thames-water (Accessed: 2026-06-10) - EIC-UK: https://eic-uk.co.uk/case-studies/deephams-upgrade/ (Accessed: 2026-06-10) - Construction News: https://www.constructionnews.co.uk/project-reports/dripping-with-innovation-on-transformed-sewage-works-01-06-2016/ (Accessed: 2026-06-10) - Adams Hendry: https://www.adamshendry.co.uk/deephams/ (Accessed: 2026-06-10) - River Lea Catchment: https://www.riverleacatchment.org.uk/index.php/london-lea-cmp/london-lea-projects/557-deephams-sewage-treatment-works-upgrade (Accessed: 2026-06-10)