Ferrovial JV wins £80m sewage treatment works job

Ferrovial has secured an £80m contract from Thames Water to upgrade the Slough Sewage Treatment Works in Berkshire.

The Spanish contractor’s UK arm will deliver the scheme for client Thames Water through an integrated joint venture (JV) between Ferrovial Construction and sister firm Cadagua, Ferrovial’s water subsidiary.

The Slough project will upgrade the existing treatment works to meet tighter Environment Agency wastewater quality standards, Ferrovial said in a statement.

Ferrovial said its work will include expanding treatment capacity to comply with more stringent permits, including reductions in ammonia and phosphorous.

Its upgrade will also improve the management of “high-strength return flows” of wastewater, the firm added.

The JV will also install a new power supply and standby systems to improve operational resilience and energy security at the site, Ferrovial added.

Design work began in November 2025. Construction is scheduled to start around 15 months later, placing the expected start date in early 2027.

Ferrovial Construction previously worked with Thames Water on the central section of the Thames Tideway Tunnel, a major sewer upgrade beneath the River Thames in London.

The £532m-turnover contractor told Construction News in 2024 that the firm was actively eyeing water framework opportunities.

He added that Cadagua is “very interested in the UK market”.