A preliminary measure was completed on this plant at the end of 2024, but it wasn’t until September 2025 that the heavy construction machinery rolled into action to begin demolition and excavation works. Since January 2026, work has moved quickly, as reinforcing steel was installed and concrete poured. The new 4th treatment stage at Donaueschingen wastewater treatment plant is now taking shape.
To remove micropollutants from the wastewater, a partial flow of 450 L/s will be treated using ozonation followed by biological activated carbon (BAC) filtration. To comply with stricter phosphorus discharge limits, an additional precipitation stage with two flocculation chambers is planned upstream of the filtration stage. With these measures, the treatment plant — designed for a capacity of 120,000 population equivalents — will make a significant contribution to water quality in the River Danube.
