Navigating micropollutant removal: five FAQs for wastewater utilities
Removing micropollutants effectively requires more than simply adding another treatment step. Utilities need to consider which technologies are best suited to their water quality, treatment goals and future requirements, and how they can be combined to optimise performance. With micropollutant removal now a key focus of the revised Urban Wastewater Treatment Directive (UWWTD), Arne Wieland, Process Engineer Expert at Xylem, answers five key questions on the technologies and approaches available.
Yes. Ozone is one of the most effective technologies for micropollutant removal, breaking down persistent compounds through direct oxidation and the formation of highly reactive hydroxyl radicals. Together, these pathways enable the removal of a wide range of micropollutants that are not readily eliminated through conventional biological treatment.
Having been used in water treatment for over a century, ozone is well proven – now with more than 100 advanced treatment systems installed or planned across Europe since 2009. Today, Xylem’s Evotide system is the leading ozone technology for micropollutant removal, while the PDOevoPLUS system provides a scalable solution for larger wastewater treatment plants, delivering high ozone volumes reliably and efficiently.
When it comes to your technology selection and design, years of operational experience and data from installed systems provide valuable insight. For further confidence, feasibility studies can support investment decisions, with Xylem offering laboratory testing to assess ozone demand, micropollutant removal and potential oxidation by-products, such as bromate, before engineering and design for very site-specific tasks or challenges.
It doesn’t have to be. While advanced treatment requires careful consideration of factors such as ozone dose, water quality and by-product formation, ozone technology is well established and can be integrated into new or existing wastewater treatment processes.
Scalable ozone systems can be easily integrated into both new and existing treatment facilities for indoors or containerised for outdoor installations. Xylem’s Evotide system is a pre-engineered design to simplify installation and ongoing operation. Its guided user interface, intuitive features and seamless digital connectivity help minimise downtime and make day-to-day operation easier for treatment operators too – so no need for much additional engineering.
A good example is adding activated carbon as a filtration step, which can further increase micropollutant removal for an even broader spectrum than typically achieved with ozone alone – which can be > 80% for targeted micropollutants. The benefits don’t stop there. Activated carbon targets substances less readily removed by ozone, while also helping to optimise ozone use. This can reduce the ozone concentration, lowering treatment costs further downstream.
Absolutely. Advanced treatment technologies can offer benefits beyond improved water quality, helping wastewater treatment plants manage energy use, operating costs and maintenance demands. Xylem’s Evotide ozone system is designed with this in mind, combining reliable oxidation with a pre-engineered design that simplifies installation and operation. Its guided user interface, intuitive features and digital connectivity help streamline day-to-day operation and minimise downtime.
At the heart of the system are Effizon® evo 3G electrodes, which incorporate Intelligent Electrode Protection (IEP) to help prevent premature electrode failure. This supports reliable operation while enabling up to 11% more energy-efficient ozone production. Together, these features can help reduce energy consumption, maintenance requirements and overall operating costs, providing important long-term benefits for treatment operators.
Micropollutant removal can play an important role in enabling greater water reuse by improving the quality of treated wastewater, making it more suitable for subsequent applications. Ozone is particularly effective at breaking down a broad range of persistent organic micropollutants and delivering disinfection credits for the treatment process. This helps to provide an additional treatment barrier beyond conventional biological processes. This can support the production of higher-quality recycled water for applications such as industrial processes, irrigation and other non-potable uses, depending on the treatment requirements. As pressure on water resources continues to grow, advanced treatment technologies such as ozone can help make water reuse a more viable part of a sustainable water management strategy.