Nijhuis Industries is awarded to build an ‘all in one’ water treatment pilot plant based on the principles of the circular economy

Dutch regional water authority Vallei en Veluwe has given the green light for a next generation water treatment factory for the town of Wilp, in the Netherlands. The new water factory will be an ‘all-in-one treatment plant’ and, in a later phase, is likely to partially replace the current ‘Terwolde’ sewage treatment plant. Alongside clean water production, the factory will also recover raw materials and resources.

Before the full-scale plant is installed, a 5 m3/h pilot plant will be built and operated for 9 months to prove the feasibility of the innovative idea. As Witteveen+Bos and Royal HaskoningDHV are responsible for the concept development, design and engineering, Nijhuis Industries will supply the complete pilot plant of this innovative water refinery plant. The plant will include a fine screen to recover celluloses, electrocoagulation unit followed by dissolved air flotation to recover organics and phosphorus, direct nanofiltration and an ion exchange unit to recover nitrogen.

At the end of last year, the Executive Board of Vallei en Veluwe gave its approval for the plan of the new water factory in Wilp (municipality of Voorst). “It’s a unique concept,” mentioned Bert van Vreeswijk of the water authority. “We have been looking for opportunities and improvements to this new treatment concept together with Witteveen+Bos over the past year. I’m glad to say that we have given the approval to build an ‘all in one’ water factory, based on the principles of the circular economy.

‘Being Circular in 2050’

By installing the water factory, the water authority is taking an important step towards being fully circular by 2050. This includes the separate collection and processing of sewage and rainwater. In the future, rainwater will no longer be treated within the sewage water treatment system. The majority of purified water from the water factory is used to improve the water quality of the ‘Twellose’ creek but water reuse for industries, agriculture and leisure activities seems possible.

Additionally, the new water factory removes 75% more nitrogen and phosphate from the polluted water in comparison to a conventional sewage water treatment. The aim is also to remove 80% of the pharmaceutical residues, produce 90% less residual streams and use no coagulation and flocculation chemicals.

Pilot project and cooperation

The Vallei en Veluwe Water Authority is working together with the municipality of Voorst, the Province of Gelderland and the Ministry of Infrastructure and Water Management. They also cooperate with companies like Attero and Schoneveld Breeding and knowledge partners Aquaminerals, STOWA and Wageningen University & Research (WUR). Witteveen+Bos, Royal HaskoningDHV and Nijhuis Industries will first produce a pilot with the water authority to test whether the innovative idea is feasible and work on the further improvement of the design of the installation.