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 The original plant had 14 sedimentation tanks in use, which have been replaced by just six Nereda tanks.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.