Abstract Summary
The Dutch drinking water company PWN ensures reliable drinking water. To produce safe water from the contaminated IJsselmeer, multiple purification steps are used. Reverse Osmosis (RO) efficiently removes organic micropollutants, like PFAS and pharmaceuticals, providing a robust solution for water purification. However, the process generates a concentrated waste stream (~20% of feed water), which is typically discharged into surface water. This research explores whether RO concentrate discharge is a future-proof solution in the context of drinking water supply security and sustainability ambitions. This research addresses the regulatory and environmental challenges associated with RO concentrate discharge: - As a result of RO, pollutants originally present in the IJsselmeer become more concentrated in the RO concentrate. PWN must comply with discharge requirements, minimizing the discharge of Substances of Very High Concern (SVHCs), such as PFAS and heavy metals, in particular. With stricter regulations anticipated, discharge may become more restricted. - PWN and Witteveen+Bos assessed the environmental impact of RO concentrate discharge using the Environmental Cost Indicator (ECI) and Rijkswaterstaat’s emission test tool. Gaps in the ECI test regarding PFAS toxicity were assessed, while the results still indicated a low global impact. However, the emission test showed that locally, some substances could become discharge-limiting. Further development of impact analysis tools and emission tests for drinking water applications is needed. In conclusion, reducing both the volume and pollutant concentration of RO concentrate discharge is essential for securing future drinking water supply. PWN aims to sustainably manage SVHCs, though available techniques have environmental trade-offs. To address this, PWN explores Minimal and Zero Liquid Discharge schemes. Reusing water from RO concentrate increases production, eases pressure on capacity, and lowers environmental impact. Additionally, recovering chemicals and energy supports the shift from a linear to a circular purification process. These efforts strengthen water security through circular practices.
