The Werdhölzli waste water treatment plant, also known as ARA Zürich-Werdhölzli, is the waste water treatment plant for the city of Zurich.
With a population equivalent of 670,000 people, it is the largest sewage treatment plant in Switzerland.
In addition to the city's wastewater, it also treats wastewater from the municipalities of Zollikon, Wallisellen and Kilchberg, as well as a partial amount from the municipalities of Adliswil, Rümlang and Zumikon.
The plant is operated by Entsorgung + Recycling Zürich.
https://www.stadt-zuerich.ch/ted/de/index/entsorgung_recycling/wissen/wasser/klaerwerk.html
Located in: Bändlistrasse 108, 8064 Zürich