Collaboration that Scales: Vechtstromen and partners accelerate Uppwater

Starting in May 2026, a 50 m³/h demonstration plant will be commissioned for a period of 18 months. The applied technology for the removal of organic micropollutants is advanced oxidation. To enhance this oxidation process, two different membrane technologies will be compared: hollow fiber nanofiltration (HFNF) and ultrafiltration (UF).

The effluent from the WWTP cannot be directly fed to the membranes; therefore, two different types of pre-treatment will be demonstrated: sand filtration and a biologically oxygen-dosed activated carbon filter (BODAC).

Working at demonstration scale is essential to serve as a reference for (inter)national implementation of the concept. In addition, the scale of the DEMO project is important to properly assess the impact and treatability of concentrated streams across the entire WWTP, in particular:

• The effect of recirculation to the biological treatment stage (accumulation of contaminants).
• Targeted treatment of problematic substances in the concentrate, such as the application of BODAC or multiple membrane stages.
• Minimization of the concentrate through optimal membrane selection.

The client also aims to gain insight into cost development, operational management, social acceptance, and the costs of scaling up. Our unique process approach focuses on efficient product development, in which the demo design is continuously evaluated against full-scale implications.

The technologies tested in the demonstration must achieve a minimum removal efficiency of 80%, the benchmark set by the future European Urban Wastewater Directive. Some technologies already reach up to 95%, but it is necessary to assess whether this level is truly required.

Another major societal water challenge is the shortage of clean freshwater. In Twente, ensuring sufficient drinking water supply is already a significant challenge. Existing sources and infrastructure are not enough to keep up with growing demand.

During dry periods, this already leads to difficulties in supplying households with water and places pressure on new housing developments at a time of housing shortages. There are numerous examples of companies that cannot be guaranteed a drinking water connection. Especially during dry periods, when pressure on groundwater reserves increases, the reuse of treated wastewater can play an important role.

To enable the reuse of WWTP effluent, treatment technology must meet the highest standards in terms of efficiency and safety. Therefore, the demonstration places strong emphasis on the quality of the produced water. Being able to treat beyond regulatory requirements means this technological concept can deliver water quality suitable for reuse as a source of freshwater or as an intermediate product that can be economically upgraded into high-grade process water.

Vitens, the Dutch drinking water company, has shown interest in the developments in Enschede, as it is exploring the use of treated wastewater as a source for drinking water production. This concept aligns with broader national ambitions to close water cycles and use available resources more efficiently.