50 Years of WEDECO: Advanced Oxidation Gains Ground
In Werdhölzli, Zürich, eight WEDECO ozone systems treat flows of up to 6,500 litres per second for micropollutant removal. (Image source: Xylem Inc.)
Micropollutants are moving onto the regulatory agenda, while water scarcity and drought are pushing more utilities towards reuse. This increases the need for processes capable of doing more than conventional treatment trains were originally designed to achieve.
Advanced oxidation combines technologies such as UV and ozone with oxidants including hydrogen peroxide. The process can target difficult organic contaminants, helping remove persistent micropollutants and produce high-quality water for reuse.
Xylem’s WEDECO brand has been active in this field since 1976. Over this period, the role of UV and ozone has expanded from established disinfection and oxidation applications to advanced processes targeting micropollutants and enabling water reuse.
In Los Angeles, treatment incorporating WEDECO UV technology at the Terminal Island Water Reclamation Plant helps produce up to 12 million gallons of recycled water each day for groundwater replenishment and industrial use. In the Netherlands, water utility Dunea worked with Xylem on a sequential advanced oxidation process that, according to Xylem, achieved organic micropollutant reductions of up to 90% while managing naturally occurring bromide.
UV, ozone and other oxidants can be combined in different ways depending on the water quality challenge at hand, and the individual technologies continue to evolve.
As micropollutant removal moves from emerging concern to infrastructure priority, ozone – also in combination with activated carbon – is increasingly being applied at scale. According to Xylem, more than 40 wastewater treatment plants in Europe are operating or will start up WEDECO ozone generators to meet the latest requirements for micropollutant removal. At the Werdhölzli wastewater treatment plant in Zürich, eight WEDECO ozone systems were deployed to treat flows of up to 6,500 litres per second. Xylem describes the installation as the largest ozone project in Europe for micropollutant removal in wastewater.
With the new WEDECO Evotide platform, Xylem has introduced the latest generation of its ozone technology. It is designed for applications including drinking water, micropollutant removal and water reuse. According to the manufacturer, the focus is on maintaining reliable ozone production under changing operating conditions and on simplifying operation, monitoring and maintenance.
According to Xylem, more than 280,000 WEDECO systems have been installed globally across municipal and industrial applications.
“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.”
The technologies behind advanced treatment are well established. What is changing is the scale and complexity of the problems they are being asked to solve. As micropollutant removal moves up the agenda and water scarcity drives greater demand for reuse, advanced oxidation could move from a specialist treatment approach to a larger role in how utilities respond over the coming decade.
Source: Xylem Inc.
