Wastewater treatment technology hired to provide enhanced ammonia removal at a village works has been purchased permanently by Wessex Water.  

The water utility, which serves south-west England, hired two Hybrid-SAF (submerged aerated filter) units from WCS Environmental Engineering to provide tertiary treatment at Pewsey Water Recycling Centre, Wiltshire. 

The units replaced two ageing SAFs in need of an upgrade. Wessex Water required alternative ammonia removal technology that could be set up quickly to ensure compliance with environmental standards was always maintained. 

Monica Rodrigues, utility manager at WCSEE, said: “We are pleased to have completed the sale of two T1000 Hybrid-SAF units, which have been successfully removing ammonia from partial effluent flows at Pewsey treatment works. By initially hiring the units, Wessex Water was able to maintain ammonia compliance quickly, while we demonstrated the technology’s compatibility with this site.” 

Each Hybrid-SAF unit achieves 8 mg/l ammonia, which they are required to meet at least 95% of the time. They are treating a combined peak flow of 12.5l/s at the site, which serves a population equivalent of 7,360. Following a trial period which proved the effectiveness of the process in maintaining compliance, Wessex Water opted to retain the units permanently.  

The patented Hybrid-SAF biological process technology employs a submerged moving-bed, fixed-film reactor which can treat wastewater with greater energy efficiency than traditional SAFs, in a tighter site footprint.  

Modular in design, with a 30% smaller footprint than comparable technologies, the units are built offsite and can be easily transported and installed quickly.  They can be hired on a short or long-term basis, for reactive or planned work, with the option of purchasing later. When no longer required on a particular site, the units can be easily transported and deployed elsewhere.