Facts & Figures

 ClientSevern Trent Water
 LocationWalsall Wood, UK
 Operation Start2019
 Project TypeGreenfield
 Process ConfigurationPre-treatment + Nereda + Disc filtration
 Nereda Design Capacity:
  • Dry Weather Flow5 MLD
  • Peak Flow646 m3/h
  • PE26,250 PE (PE = 60 gBOD/d)
 In the Media:Two more Severn Trent treatment works to get Nereda technology
 UK Water Projects - Walsall Wood STW (2019)

About the Nereda® WWTP in Walsall Wood, UK

Walsall Wood wastewater treatment plant (WWTP) is located in the North of the West Midlands region in the UK.

The challenge

Walsall Wood WWTP needed to be upgraded by operators Severn Trent Water, in order to comply with stringent new standards for phosphorus and ammonia levels in wastewater. The company required a solution that would deliver the necessary environmental benefits, at the same time as being cost-effective in terms of capital expenditure and whole-life costs. It was also essential that the upgrade had the capacity to process a population equivalent of 26,250, with peak flow operating at 646 m³/hour.


Mott MacDonald Bentley was selected as the contract’s delivery partner. Complete asset replacement was required at Walsall Wood WWTP and Nereda technology was identified as the first-choice solution. It was also deemed to be the cheapest solution on CAPEX as well as on OPEX. Construction of three Nereda reactors, each with a capacity of 1500m³, started in early 2018, with waste sludge discharging to a transfer sewer as part of the new design. The upgrade to the WWTP means that Walsall Wood will meet stringent new standards for phosphorus and ammonia levels.


Since becoming operational in April 2019, the Nereda installation at Walsall Wood now adheres to the very tight regulations required under Severn Trent Water’s permit agreement. As a result, the quality of the effluent put back into nearby water courses is significantly improved. The whole-life cost of implementing a Nereda plant at Walsall Wood WWTP made it a natural choice for the upgrade. It will be fully compliant by summer 2019.

    The local benefits of the project

    Nereda logo small Low capital expenditure 
    Nereda logo small Vastly improved water quality
    Nereda logo small Environmental benefits
    Nereda logo small Enhanced capacity 
    Nereda logo small  Water regulation compliant