Vienna’s sewer utility Wien Kanal has put into service a rainwater pump that moves 15,000 litres per second at the Donauinsel pumping station. The city announced on 19 October 2026 that it is the most powerful of its type in Europe. The pump raises the station’s peak capacity to 60,000 litres per second and gives the Floridsdorf and Donaustadt districts more protection against heavy rain.
What changes at the station
The Donauinsel station was built between 1970 and 1980 as part of a large sewer programme linked to the construction of the Donauinsel. With an installed electrical capacity of almost 10 megawatts, it is the main node for wastewater from districts 21 and 22. On a dry day it carries between 600 and 2,000 litres of wastewater per second under the Danube to the treatment plant in Simmering. During heavy rain, its rainwater pumps can release combined sewage into the Danube so that streets do not flood.
| Before | After | |
|---|---|---|
| Pumps | 3 wastewater, 6 rainwater | plus 1 new rainwater pump |
| Peak capacity | 45,000 l/s | 60,000 l/s |
The new unit is a vertical pipe-casing pump. Two 6 kV frequency converters now let the two existing rainwater pumps of 10,000 litres per second each adjust their speed to the inflow, which saves energy and extends motor life. Instead of an electric chiller, the motors are cooled with well water through a heat exchanger.
Cost, timing and building upgrades
The €18 million project took 22 months from tender to commissioning. It follows the destructive storm of September 2024, during which the station was successfully deployed. The building was also renovated: a 260-kilowatt solar plant now covers about 3,000 square metres of roof, and a heat pump replaced oil heating, saving Wien Kanal 300 tonnes of CO2 and about €50,000 a year. The control centre on the Donauinsel, which steers the city’s 2,500-kilometre sewer network, received new hardware and software.
What happens next
The city has commissioned planning for two linked projects. An underground storage basin on the Donauinsel, with a capacity of about 100 million litres, would temporarily hold wastewater if a pumping station fails and reduce combined sewer overflows into the Danube during rain. A second pipe, about 500 metres long, would run under the Danube to the Simmering treatment plant, keeping wastewater disposal for districts 21 and 22 working if the existing link is unavailable.