Anglian Water has installed specialist wastewater treatment equipment in a major water recycling centre (WRC) upgrade.
The work was needed to ensure dry weather flow remained compliant at Horning Knackers Wood WRC in Norfolk.
River flooding and groundwater infiltration into the network was causing problems, and conventional equipment on site had proved unsustainable due to changes in ground conditions and hydrology in the area.
Soil in the region is predominantly peat over sand and gravel, which is porous and has low cohesion. This means it is subject to continual movement, which added pressure on the pipe joints.
Combined with a high-water table, this resulted in groundwater infiltration into the pipes, augmenting volumes, and increasing the challenge of meeting environmental consents at the works.
Anglian Water wanted to protect infrastructure integrity and support wider drainage resilience, while ensuring long-term water recycling needs for the Horning area.
The company called in WCS Environmental Engineering (WCSEE), who installed 10 Hybrid modular biological treatment units and two Flocell XFMs for tertiary solids removal.
WCSEE worked with contractor Kier to install, test and commission the wastewater equipment.
To ensure the proposed solutioned aligned with the unique onsite challenges, they also conducted preliminary background work in collaboration with engineers, suppliers and logistics departments within Kier, including organising transport and manufacturing slots.
The upgraded WRC now has the capacity to treat flows of 25l/s, with a consent of 20mg/l for total suspended solids, 10mg/l for ammonia, and 10mg/l for biochemical oxygen demand – providing a retention time of greater than two hours.
The patented Hybrid technology employs a submerged moving-bed and fixed-film reactor, proven to treat wastewater with energy efficiency compared to other submerged Hybrids.
The flow balancing in the primary tank means it can handle variable flows and loads, making it ideal for the seasonal and variable demands in Norfolk.
The Flocell XFM modular filtration systems were originally developed for pond filtration applications for high value koi carp. They have been successfully adapted for wastewater treatment and installed at Horning Knackers Wood WRC for tertiary solids removal.
The open-cell media is designed to efficiently reduce tertiary solids and soft, difficult-to-manage flocs, retaining particulates without increasing pressure within the filter or reducing flow. The units can be operated under pumped or gravity flow and can be used inline or on a multi-pass flow mode.
