Mogden is the third largest Sewage Treatment Works in the UK, serving over two million people across south-west London. Our work at the site is to plan and deliver a £66m refurbishment and upgrade process which will ensure Mogden remains resilient to achieve a Flow-to-Full-Treatment of 1064 Million Litres per Day.

Natural resources, Nuclear & Networks
Design and build
Natural Resources






people served by the treatment works



hectare site


Our brief at Mogden is to deliver a multi-disciplinary programme of works that includes design, construct and commissioning of multiple packages of work to improve the site’s resilience and capacity. The works include improvements to the Primary and Secondary treatment process as well as increasing the resilience of the Sludge Treatment, to help improve digestion and biogas generation. The Project is further providing a new process control network and SCADA system, which is effectively the nerve system of the Sewage Treatment Works. 

The site upgrades will allow improved safety, design management, construction, quality and commercial performance – futureproofing operations and delivering a more efficient and resilient plant.

The Project is further developing a Building Information Modelling (BIM) construction management software to plan, deliver and support the effective handover of the works.