Nereda design capacity

  • 4784 m3/d
    Dry Weather Flow
  • 646 m3/h
    Peak Flow
  • 26250 PE
    PE (PE = 60 gBOD/d)

Project facts

  • Client
    Severn Trent Water
  • Location
    Walsall Wood, UK
  • Period
  • Wastewater
  • Project type
  • Process configuration
    Pre-treatment + Nereda + Disc filtration

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.

The solution

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.

The outcome

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.


  • Low capital expenditure 

  • Vastly improved water quality

  • Environmental benefits

  • Enhanced capacity 

  • Water regulation compliant