Three UK water utilities are installing a total of 30 Hybrid-SAF modular biological treatment units to meet the demands of a growing population and stricter regulations.
Anglian Water, Scottish Water, and United Utilities have all signed contracts with WCS Environmental Engineering (WCSEE) for their wastewater treatment technology.
WCSEE is working closely with Anglian Water and its infrastructure delivery partner @One Alliance, on the installation of 18 Hybrid-SAFs (submerged aerated filters) at Dereham & Swanton Morley Water Recycling Centre (WRC) in Norfolk. This is an area where the population is predicted to grow significantly, requiring new housing developments.
WCSEE utility manager Andrew Haywood said, “The installation of 18 Hybrid-SAFs at Dereham WRC will be configured as three streams of six tanks, with flow splitters specifically designed for the biological treatment stage. Within two weeks of installation, as the biological process becomes fully operational, the 18 units will be able to handle flow rates up to 22.6 litres a second (l/sec) with average flows of 12 l/sec.”
As part of the UK Government’s Levelling Up & Regeneration Bill, Anglian Water could also have a legal duty to upgrade Dereham WRC by 2030 to achieve stricter effluent standards of 0.25mg/l for phosphorus and 10mg/l for nitrogen. The design of the new Hybrid-SAFs is futureproofed to help achieve these higher standards.
WCSEE is also providing nine units to Scottish Water, working with ESD, for the upgrade of East Linton wastewater treatment works in East Lothian, which is adapting to increased pressure on the plant due to population growth.
The third agreement is with United Utilities and C2V+, which requires three Hybrid-SAFs to reduce ammonia levels in effluent discharged at a small wastewater treatment plant in Cheshire, as part of the company’s capital improvement plan. The upgrade follows a tightening of the Environment Agency consent.
Haywood said, “WCSEE is proud that the Hybrid-SAF technology has been selected by these three utilities to meet their challenges on population growth and the tightening regulatory landscape. WCSEE has long been an approved or framework supplier for Anglian Water, Scottish Water, and United Utilities, and we look forward to developing these relationships further, by working closely with them on these expansion and upgrade projects.”
The patented Hybrid-SAF technology employs a submerged moving-bed and fixed-film reactor, proven to treat wastewater with energy efficiency compared to other submerged SAFs. The flow balancing in the primary tank means it can handle variable flows and loads, making it ideal for seasonal and variable demands.
Historically, the Hybrid-SAF was preferred for smaller populations in rural locations; however, its design has proved versatile and flexible for use in a wide range of locations.
Hybrid-SAF treatment units are built offsite in controlled conditions and easily transported to site, ready for installation. They can be moved between locations as needs and requirements change – minimising onsite disruption, reducing waste, and optimising site footprint.
Haywood adds, “It is also possible to rapidly augment or retrofit existing plant processes. New-build installations are now being specified for higher volumes than ever before, with the process suitable for up to 4,250 population equivalents based on the ammonia load.
