Nereda design capacity

  • 76271 m3/d
    Dry Weather Flow
  • 14119 m3/h
    Peak Flow
  • 308333 PE
    PE (PE = 60 gBOD/d)

Project facts

  • Client
    Water Authority Stichtse Rijnlanden (NL)
  • Location
    Utrecht, The Netherlands
  • Licensee
  • Wastewater
  • Project type
  • Process configuration
    Pre-treatment + Nereda + Sand filtration

About Utrecht Nereda® WWTP - The Netherlands

The award-winning Utrecht plant is the largest Nereda plant constructed to date in the Netherlands. Utrecht is the fourth largest city and a municipality of the Netherlands. It is the capital and most populous city of the province of Utrecht in the heart of mainland Netherlands.

The Netherlands - Utrecht | Royal HaskoningDHV
Image: The existing situation with the vacant lot where the new new sewage treatment plant will be built. © by Heijmans and GMB

The challenge

The city of Utrecht required an upgrade to replace the current outdated installation, to meet the more rigorous effluent demands placed upon it by an increased population. Following a public tender, in April 2016 the Dutch construction companies Heijmans and GMB were awarded the contract to build a new municipal wastewater treatment plant by water authority De Stichtse Rijnlanden. The €120 million project comprised the design, construction and 10-year maintenance of the plant, which uses Nereda wastewater treatment technology.

The Netherlands - Utrecht | Royal HaskoningDHV

The solution

Heijmans-GMB was awarded the contract based on its selection of Nereda technology to purify the municipal wastewater, to meet the stringent effluent requirements within a compact plant. Two important effluent parameters for the project were for nitrogen (N total: 5 mg/l) and phosphate (P total: 0.5 mg/l). The obsolete WWTP was originally built in 1959, and construction work to rebuild it commenced in 2017. Due to the location of Utrecht’s sewer system, it was decided to build the new installation on the existing site. Owing to the Nereda technology’s compact nature, it was possible to construct it alongside the existing plant. The new wastewater treatment plant is capable of removing twice as much nitrogen and phosphate from the water. The purification process of the plant is much faster, so as well as being 30% more energy efficient compared to the original plant, it is also considerably smaller. With no need for large post-settling tanks, a great deal of space has been saved. The original plant had 14 sedimentation tanks in use, which have been replaced by just six Nereda tanks. The old plant was removed from service once the new plant had been commissioned.


The Netherlands - Utrecht | Royal HaskoningDHV

Image: The lay out of the new WWTP (marked within the dotted lines) the showing the small footprint. © by Heijmans and GMB

The outcome

The Utrecht project is now complete and the 10-year maintenance period has commenced. The fact that Nereda was again selected by a Dutch water authority demonstrates the technology’s popularity and reputation for delivering excellent results in the Netherlands and across the globe. Operational since 2018, the Nereda plant at Utrecht is the largest constructed so far in the Netherlands, with an average daily flow of 76,271 m³ and a capacity of 308,333 p.e.

The Netherlands - Utrecht | Royal HaskoningDHV
Image: The new sewage treatment plant in Utrecht


  • Meets stringent requirements

  • Enhanced capacity

  • Compact footprint

  • Awarded GWA

  • Wastewater project of the year 2019