MICROPOLLUTANT REMOVAL WITH OZONE, BIRMENSDORF

The Birmensdorf Wastewater Treatment Plant, located in Switzerland, has been in operation since July 1973. It serves several municipalities, including Aesch, Birmensdorf, Bonstetten, Stallikon, Uitikon, Wettswil, and parts of Aeugstertal. As part of a long-term development plan extending to the year 2035, the plant underwent a significant expansion between 2013 and 2018. This upgrade increased its treatment capacity to serve up to 33,000 population equivalents.

In response to the revised water protection legislation in Switzerland, the Birmensdorf facility has recently been modernized with an advanced treatment stage specifically designed to remove micropollutants from wastewater. These substances, which include trace pharmaceuticals and personal care products, are increasingly recognized as environmental contaminants that conventional treatment methods cannot fully eliminate.

To meet these new requirements, the plant implemented ozone treatment—a proven and efficient method for advanced wastewater purification. Ozone, a powerful oxidizing agent, breaks down complex organic compounds and significantly reduces micropollutant concentrations.
At Birmensdorf, the ozone system was designed to treat a continuous wastewater flow of 464 liters per second. For this purpose, two ozone generators (model GM36) were installed, with a total ozone production capacity of 4.4 kilograms of ozone per hour. The ozone is evenly distributed into the water through high-performance ceramic diffusers, ensuring maximum contact and effective treatment.

The project was carried out by Rheno AG, which managed the detailed engineering, equipment delivery, installation, and commissioning of the ozone stage. This upgrade not only enhances the plant’s treatment performance but also ensures compliance with stricter environmental standards and contributes to long-term water protection in the region.

To learn more about the project and the benefits of ozone treatment for micropollutant removal, read the full case story about the Birmensdorf Wastewater Treatment Plant.