Ferrovial has secured a new contract in the United Kingdom’s water sector, reinforcing its position in critical environmental infrastructure. The company will deliver an upgrade of the Slough Sewage Treatment Works (STW) for Thames Water, under a project valued at approximately £80 million.
The scheme will be carried out through a joint venture between Ferrovial Construction and Cadagua, combining local delivery capabilities with international technical expertise. The appointment further develops Ferrovial Construction’s established working relationship with Thames Water, following its involvement in major infrastructure programmes across the UK.
At Slough STW, the works are aimed at aligning the facility with updated wastewater discharge requirements set by the Environment Agency. The project includes an expansion of treatment capacity to meet more demanding quality permits, including tighter limits on ammonia and phosphorous. In addition, improvements will be made to the management of high-strength return flows to comply with storm permit conditions.
Operational resilience and sustainability also form a central part of the upgrade. A new power supply and standby systems will be installed to strengthen reliability and support long-term performance. Upon completion, the improvements are expected to contribute to cleaner receiving waters and healthier local ecosystems.
Design activities for the scheme commenced in November 2025, with construction anticipated to start around 15 months later. The timeline reflects the technical complexity of upgrading an operational wastewater facility while maintaining service continuity.
With more than two decades of experience delivering complex infrastructure in the UK, Ferrovial Construction brings extensive knowledge of regulated environments. Cadagua complements this with over 50 years of experience in water and wastewater treatment projects in Spain and internationally.
