February 27, 2025
Our students of the course Sustainable Water Management took part on a field trip with course instructor Prof. Zoltan Illes on February 17, 2025, and got an inside look at one of the most efficient wastewater treatment plants in the world, the Vienna Main Wastewater Treatment Plant Simmering! Not only do they clean the water before releasing it into the Danube, but they also generate electricity from water outflow and produce biogas from sediment.
The expanded main wastewater treatment plant of Vienna was inaugurated in 2005. The location in Simmering was a good choice, as it is one of the topographically lowest points of the city and the natural gradient of the sewers allows the wastewater from all Viennese households to drain through the 2,400 kilometre long sewer system. There the solid matter is first eliminated mechanically and then the is water cleaned biologically. This is a milestone in the protection of waters and in environmental quality in Vienna. The core of Vienna’s water protection measures spreads over 40 ha - approx. 0.1 percent of the entire city area - and contributes to keeping the Danube clean.
Fun fact: The treated water is so clean that, in theory, you could drink it! (Though they still wouldn’t recommend it). Surprisingly, the Danube itself is actually dirtier than the outflow.
A specialist walked the team through the entire process, answered all their curious questions, and showed them around the large plant—bigger than Vatican City! The experience gave students a whole new appreciation for sustainable water management and innovation in action.