Why advanced oxidation is entering a critical decade for water treatment

Persistent micropollutants, water scarcity and growing demand for water reuse are changing what utilities require from advanced water treatment. Processes once deployed for comparatively specialised applications are increasingly being considered as part of the response to emerging water quality challenges. Advanced oxidation is one example. By combining technologies such as ultraviolet (UV) treatment and ozone with oxidants including hydrogen peroxide, these processes can target organic contaminants that conventional treatment systems were not necessarily designed to remove. For Xylem’s WEDECO business, which marks 50 years of water treatment technology development in 2026, that changing role represents a significant evolution from the established disinfection and oxidation applications of UV and ozone.

Micropollutants change the treatment challenge

Micropollutants are becoming an increasingly important consideration for water and wastewater utilities, particularly as treatment requirements evolve. At the same time, drought and pressure on available water resources are increasing interest in producing high-quality treated water suitable for reuse. Advanced oxidation processes can combine UV, ozone and oxidants in different configurations depending on the contaminants and water quality involved. Rather than relying on a single treatment mechanism, these combinations can be designed around specific treatment objectives. The individual technologies are also continuing to develop as utilities seek treatment systems capable of operating reliably and efficiently at larger scales.

Dunea targets organic micropollutants in the Netherlands

One example can be found at Dutch water utility Dunea, where Xylem and the utility worked on a sequential advanced oxidation process designed to address organic micropollutants while managing naturally occurring bromide. According to Xylem, the process achieved reductions of up to 90% in organic micropollutants. WEDECO reactors form part of the treatment process. The project demonstrates how combinations of advanced treatment technologies can be configured around specific water chemistry rather than applying a standard treatment approach to every site.

Ozone deployment expands across European wastewater treatment

Ozone is also taking on a larger role in European wastewater treatment as micropollutant removal becomes a greater infrastructure priority. More than 40 wastewater treatment plants in Europe are operating, or are due to begin operating, WEDECO ozone generators for micropollutant removal, according to Xylem. One of the largest installations is at the Werdhölzli wastewater treatment plant in Zürich, Switzerland. Eight WEDECO ozone systems have been deployed to treat flows of up to 6,500 litres per second. Xylem describes Werdhölzli as Europe’s largest ozone project for micropollutant removal in wastewater, demonstrating the potential for the technology to move beyond smaller specialist applications into large-scale municipal treatment.

Advanced oxidation supports water reuse in Los Angeles

The role of advanced treatment is also developing alongside water reuse. At the Terminal Island Water Reclamation Plant in Los Angeles, treatment incorporating WEDECO UV technology helps produce up to 12 million gallons of recycled water each day. The treated water is used for groundwater replenishment and industrial applications, providing an example of how advanced treatment technologies can support alternative water supplies in areas facing long-term pressure on conventional resources. As more utilities investigate potable and non-potable reuse, treatment performance must be considered alongside factors including reliability, energy use, maintenance and operational complexity.

Next-generation ozone technology focuses on operational reliability

Xylem has continued to develop its ozone portfolio with the introduction of the WEDECO Evotide platform. Designed for applications including drinking water treatment, micropollutant removal and water reuse, the technology is intended to maintain ozone production as operating conditions change. The platform also focuses on simplifying operation, monitoring and maintenance. These considerations are becoming increasingly important as advanced treatment moves into larger installations where performance must be maintained continuously and at scale.

“Treatment performance is no longer enough on its own,” said Géraud de Saint Exupéry, Senior Vice President and General Manager, Global Treatment, Xylem. “As utilities face more complex water quality challenges, advanced treatment must also be efficient, reliable and practical to operate at scale. That is where the next generation of technology has to deliver.”

WEDECO reaches 50 years in water treatment

WEDECO’s development of UV and ozone technologies dates back to 1976. Xylem says more than 280,000 WEDECO systems have now been installed globally across municipal and industrial applications. Over that period, the applications for the technologies have expanded from established disinfection and oxidation processes into areas including advanced micropollutant removal and water reuse. The underlying technologies are therefore not new. What is changing is the scale and complexity of the water quality challenges they are increasingly being deployed to address.

Advanced oxidation moves towards a larger treatment role

The coming decade could further change the position of advanced oxidation within municipal treatment. Micropollutant removal is becoming a more prominent infrastructure requirement, while water scarcity is increasing pressure on utilities to recover and reuse water that might previously have been discharged. Those trends create a need not only for higher levels of treatment but for technologies that can deliver them reliably without creating unsustainable operational complexity. For advanced oxidation, the challenge will increasingly be how established UV and ozone processes can be combined and engineered to provide the treatment performance, efficiency and operational resilience required for deployment at scale.