Ferrovial and Cadagua to Deliver Major Upgrade of Slough Sewage Treatment Works for Thames Water

Ferrovial and Cadagua to Deliver Major Upgrade of Slough Sewage Treatment Works for Thames Water

(IN BRIEF) Ferrovial has secured an approximately £80 million contract with Thames Water to upgrade the Slough Sewage Treatment Works through a joint venture with Cadagua. The project will expand treatment capacity, improve removal of ammonia and phosphorus, enhance storm-flow management and install new power and backup systems to meet stricter Environment Agency standards. Building on Ferrovial’s track record in major UK infrastructure, the upgrade is intended to deliver more resilient wastewater services, support environmental goals and improve the health of surrounding waterways.

(PRESS RELEASE) AMSTERDAM, 17-Feb-2026 — /EuropaWire/ — Ferrovial has been awarded a contract to upgrade the Slough Sewage Treatment Works for Thames Water, delivering an infrastructure scheme valued at approximately £80 million. The project will be carried out through a joint venture between Ferrovial Construction and Cadagua, combining engineering expertise and specialist water-treatment capabilities.

The initiative strengthens Ferrovial Construction’s long-standing partnership with Thames Water, following its involvement in major infrastructure programmes such as the Thames Tideway Tunnel. The new project reflects Ferrovial’s continued focus on delivering resilient infrastructure designed to support growing environmental and community needs.

The Slough facility will undergo significant modernization to meet updated wastewater quality requirements set by the Environment Agency. Planned improvements include increasing treatment capacity to comply with tighter discharge standards, particularly in reducing ammonia and phosphorus levels, and enhancing storm-flow management to better handle high-strength return flows. The upgrade will also incorporate a new power supply and standby systems aimed at improving operational reliability and long-term sustainability. Once completed, the improvements are expected to contribute to cleaner watercourses and healthier local ecosystems.

Design work for the scheme began in November 2025, with construction anticipated to commence roughly 15 months later. Ferrovial Construction brings over two decades of experience delivering complex UK infrastructure projects, while Cadagua contributes more than 50 years of expertise in water and wastewater treatment and desalination technologies across Spain and international markets.

The project aligns with Ferrovial’s strategy of integrating global technical knowledge with local project delivery to reinforce the United Kingdom’s environmental objectives and enhance the resilience of critical water infrastructure.

Media Contact:

Isabel Muñoz
+34 660528832
mimunoz@ferrovial.com

SOURCE: Ferrovial