A joint venture between Costain and MWH Treatment (CMDP) has scooped a number of multi-million-pound contracts with Southern Water as part of the water company's AMP7 investment programme.

The combined work is valued at £65 million and will run until late 2025. The projects will see the joint venture improve the resilience of the local water supply and upgrade wastewater treatment works at Testwood near Southampton, and Burham in Kent.

The integrated CMDP team will work closely with Southern Water and its engineers across both sites to develop cost-efficient solutions, optimise asset performance and deliver the implementation through to the end of AMP7. Both sites will benefit from major renovation, refurbishment and expansion of existing assets to cope with rising demand for drinking water and increasing volumes of wastewater.


At Testwood Water Supply Works, the CMDP-JV will be refurbishing and making improvements to abstraction points from the River Test, pumping stations and flow and filtration assets. The work will also include upgrading the rapid gravity filtration facilities and repurposing contact reservoir tanks at the site.

At Burham Water Supply Works, the joint venture will carry out improvements including a full refurbishment of the low lift pumping station and granular activated carbon filters, and site-wide chemical dosing upgrades. CMDP is also working on a number of upgrades to improve the resilience of the water treatment works, including increasing the usable volume of the lake that feeds the site.

Chris Hodgson, programme director for the CMDP-JV commented: "Southern Water is upgrading its infrastructure to ensure it continues providing clean drinking water to its customers while improving resilience for the future. This is important work that will have a transformative impact on the lives of residents and local communities. We will continue to deliver innovative solutions to Southern Water to not only ensure we support them in meeting their regulatory obligations, but also to add value by identifying opportunities to increase efficiencies."