Thames Water is taking significant steps to enhance its sewage treatment capabilities in Cirencester and Oxford, addressing climate challenges and population growth.
- The Cirencester STW upgrade involves a £21M investment aimed at nearly doubling the site’s wastewater treatment capacity.
- Contractor Tilbury Douglas is constructing an innovative 9,000m2 high infiltration reed bed to improve effluent quality.
- Thames Water is also preparing for a major £240M contract to upgrade the Oxford STW.
- Both projects signal Thames Water’s commitment to improving infrastructure resilience against environmental pressures.
Thames Water is embarking on a substantial £21M upgrade project at the Cirencester sewage treatment works (STW), with a focus on increasing the capacity and efficiency of the site. The primary objective is to combat the effects of climate change and accommodate the growing population. By nearly doubling the current capacity from 269l/s to 484l/s, the site aims to significantly enhance its wastewater treatment capabilities.
The upgrade at Cirencester is marked by the construction of a 9,000m2 high infiltration reed bed (HIRB) by contractor Tilbury Douglas. This innovative natural filtration system is designed to supplement the treatment process, ensuring that up to an additional 114l/s of wastewater can be efficiently processed. The HIRB’s ability to reduce storm overflow risks during heavy rainfall is expected to greatly reduce pollution in local rivers, delivering a superior quality of effluent to the environment once complete in spring 2025.
Paul Parfrey, Thames Water project manager, emphasised the importance of resilience in their infrastructure, highlighting the necessity of these upgrades in facing climate and demographic challenges. Meanwhile, Gloucestershire County Council’s Lisa Spivey expressed her admiration for the scale of the reed bed project, anticipating that it will mitigate sewage discharge issues in nearby rivers, including the Churn, Thames, and Coln.
In preparation for future demands, Thames Water has also announced plans for a significant £240M upgrade at its Oxford STW. The project aims to meet rigorous new quality permits by reducing ammonia consent levels and total phosphorus in effluents. Additionally, enhancements in flow capacity and storm tank capacity, along with revamped treatment and power systems, are integral to this initiative. A launch event will outline project details on 10 September, with the formal contract notice expected in October.
Thames Water’s proactive approach demonstrates a commitment to modernising vital infrastructures to meet future environmental and urban demands.
