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Xylem to supply ozone treatment technology to Switzerland’s largest wastewater facility

Xylem has been awarded a contract to provide advanced treatment technology to the largest wastewater treatment facility in Switzerland.

Xylem’s ozone technology will enable the Werdhölzli wastewater treatment plant in Zurich, serving 434,000 people, to meet new Swiss regulations regarding the protection of water bodies and specifically the removal of micropollutants.

Peter Wiederkehr, COO at Entsorgung + Recycling Zürich explained: “Wastewater treatment plants serving a population of 5,000 or more must be equipped now with a new treatment stage which ensures that up to 80% of pre-selected micropollutants are removed. Extensive research has confirmed ozone as a preferred technology for this stage.

Xylem will supply eight Wedeco SMOevo ozone systems to the Werdhölzli plant as part of a 50 million Swiss franc (€45.7m) upgrade project.

Once operational, the plant will be able to produce 153kg/h of ozone to treat a  flow of 6,500l/s, making it the largest ozone plant for the removal of micropollutants in the world.

Micropollutants are contaminants that are released from everyday products such as industrial chemicals, pharmaceuticals and personal care products (PPCPs), pesticides, and hormones, and cannot be removed with conventional wastewater treatment technologies.

“While conventional treatment processes do not remove them completely, oxidation with ozone is proving to be one of the most efficient methods for reducing these contaminants. Pollutants, coloured substances, odours, and micro-organisms are directly destroyed by oxidation, without creating harmful chlorinated by-products or significant residues,” said Florian Milz, key account manager at Xylem.

Growing concern about micropollutants is leading many countries to consider more rigorous treatment solutions.

The EU has published a list of prioritised substances that pose a threat to ground and surface water sources.

To adhere to the environmental standards set by the EU, the member countries have to regularly monitor the occurrence of the listed substances.

Construction on the Werdhölzli wastewater treatment plant upgrade began in 2016 and the plant is expected to be operational by 2018.