Real-World Implementations for the Removal of Micropollutants from Wastewater

The Urban Wastewater Treatment Directive (Directive (EU) 2024/3019) introduces major reforms in municipal wastewater management, including stricter nutrient removal standards, energy neutrality requirements, and, for the first time, targeted elimination of micropollutants (fourth treatment stage). Financing is guided by the extended producer responsibility principle. Plants serving >150,000 population equivalents (PEs) must implement micropollutant removal by 2045, with intermediate targets in 2033 (20%) and 2039 (60%). Additional requirements apply to areas >10,000 PE where environmental or health risks exist. In Germany, approximately 100 large and 580-600 medium-sized plants will require upgrades, with a minimum removal efficiency of 80% for selected micropollutants. Switzerland has already implemented micropollutant removal under its Water Protection Ordinance (2016). This chapter reviews real-world implementations, focusing on treatment technologies, current implementation status, and financial aspects in Germany, other EU countries, and Switzerland. Full-scale technologies include adsorptive processes (PAC, GAC) and oxidative processes (ozonation). PAC can be dosed into the activated sludge process, a separate adsorption stage, or before a filter; GAC is used downstream as an adsorber or fluidised bed. Ozonation requires biologically active post-treatment, often combined with GAC in biologically activated carbon (BAC) processes. Emerging innovations include PAC before ultrafiltration membranes, retention soil filters, and advanced oxidation processes (AOPs). Implementation of these technologies varies: North Rhine-Westphalia predominantly uses ozonation and Baden-Württemberg PAC/GAC, and new combinations are under planning. Switzerland operates 33 plants, with 40 more planned, while Sweden conducts extensive pilot tests and the Netherlands has an innovation programme from the establishment of micropollutant elimination. Financial analyses indicate overall investment costs of EUR 1.7-18.8 million and operating costs of EUR 0.83-8.3/PE*a, with larger plants being more cost-efficient. Germany's and Switzerland's extensive experience and ongoing research support successful implementation of future legal requirements and protection of water resources.