… at an excursion to the waste water treatment plant Werdhölzli.
Ever wonder where your water goes after the flush? Join us for an exclusive excursion to the Werdhölzli wastewater treatment plant and witness the miracle of purification firsthand. In just three hours, what leaves your home transforms into crystal-clear water returning to the Limmat.
Explore the massive five-stage cleaning process, meet some of the 90 experts keeping the city flowing, and see how 2,200 liters per second are reborn. You will get a fascinating look behind the scenes of one of the heroes of our ecosystem.
There are only 25 spots available, so don’t forget to sign up here !
Date: 17.04.2026 14:45-17:00
Location: either 14:15 at ETH Center Campus (Meetingpoint Polybahn),
or directly at 14:45 at the location of the Werdhölzli plant, Bändlistrasse 108, 8064 Zürich
Key Facts:
- The Werdhölzli wastewater treatment plant purifies an average of 2,200 liters of wastewater per second, reaching up to 6,000 liters per second during heavy rainfall.
- After a five-stage purification process, ERZ releases the clean water into the Limmat, thereby continuing the water cycle.
- Approximately 90 employees operate and monitor the plant, maintain the facilities, and manage the necessary infrastructure.
- Wastewater arrives at the Werdhölzli plant no later than three hours after you flush your toilet.
A picture of the wastewater treatment plant
