KWR and Rijkswaterstaat launch large-scale innovative monitoring project for water quality

KWR has a long history of successful collaboration with Rijkswaterstaat (RWS) in the field of chemical monitoring. The two organisations have worked together well for many years in areas such as HPLC-UV monitoring, Non-Target Screening with High Resolution Mass Spectrometry and data analysis. See, for example, HPLC-UV screening project – KWR.

Discharges of chemical substances in the picture

Surface water is of major importance for drinking water supplies, leisure activities and ecosystems. Water quality can be affected by wastewater treatment plants (WWTPs), which discharge treated wastewater (effluent): the substances contained in that effluent can affect the quality of the wastewater and therefore of surface water. However, the substances entering surface water in these discharges are often not yet adequately understood because WWTPs receive effluent consisting of both industrial and domestic wastewater.

Amendment of EU Urban Wastewater Directive

With the amendments to the EU Urban Wastewater Directive, there are new requirements for WWTPs with respect to nitrogen (N) and phosphorus (P), as well as the removal of micro-pollutants. In the Netherlands, the implementation of this directive in legislation and regulations is being led by the Ministry of Infrastructure and Water Management.

An element of the new regulations is Extended Producer Responsibility (EPR). This means that producers from the cosmetics and pharmaceutical sectors contribute to the cost of additional treatment steps needed to remove micropollutants from wastewater. To establish an overview of potentially environmentally-harmful substances that enter, and are discharged from, WWTPs, the scope of the screening of incoming (influent) and outgoing, treated, water (effluent) from WWTPs needs to be extended.

Research looking at influent an effluant

To identify exactly which substances are present in wastewater, this study will look at both influent and effluent from a total of twenty wastewater treatment plants across the Netherlands over a period of approximately eighteen months. Samples will be taken three times during that time: in summer 2026, in autumn 2026 and in spring 2027. A total of some 200 samples will be studied, most of them at KWR. Spring and autumn samples will be taken during a relatively dry and a relatively wet period. In summer, the samples will be taken only during a dry period.

The WWTP operators will take the samples, which will be examined in target substance analyses (concentrations of indicator compounds) and suspect and non-target screening (NTS) looking only at signals based on similarities with one or more substance libraries. See for example Measuring and identifying pollutants – KWR (in Dutch).

The data from this project are relevant not only for the Ministry of Infrastructure and Water Management, Rijkswaterstaat and KWR, but also for national and international research and policy, such as the national Working Group for Tackling Emerging Substances (WAOS), and for the implementation of the Urban Wastewater Directive including Extended Producer Responsibility. In addition, Rijkswaterstaat and KWR are both active in the international NORMAN network, where there is considerable interest in the large-scale and systematic monitoring data of wastewater and surface water.

Would you like more information? For general questions, please contact Ton van Leerdam. If you have substantive questions, please contact Patrick Bäuerlein.