StStefan im Rosental Wastewater Treatment Plant, Sankt Stefan im Rosental, Austria

The StStefan im Rosental wastewater treatment plant is located in Sankt Stefan im Rosental, a municipality in the Steiermark region of southeastern Austria. The plant serves a population equivalent of 5,722, classifying it as a small to medium agglomeration under Austrian and EU regulations. Its advanced treatment level ensures high-quality effluent suitable for discharge into sensitive environments. As an advanced treatment facility, the plant goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, which is typical for plants in sensitive catchment areas under the EU Urban Waste Water Treatment Directive (91/271/EEC). The plant has a designed capacity of 6,300 m³/day and currently treats an average daily flow of 656.64 m³/day, indicating significant spare capacity for future growth. The treated effluent is discharged into local watercourses that ultimately drain into the Mur River, a major tributary of the Drava River, which flows into the Danube and then the Black Sea. The plant plays a crucial role in protecting the water quality of these rivers and the downstream ecosystems, including the Danube Delta, a region of high ecological importance.

The plant discharges into local streams that feed into the Mur River, a significant watercourse in Styria. The Mur flows southeast into the Drava River, which joins the Danube near Osijek, Croatia. The Danube then empties into the Black Sea via the Danube Delta. This watershed supports diverse aquatic life and is an important migratory corridor for fish species. The advanced treatment at StStefan im Rosental helps reduce nutrient loading, protecting downstream water bodies from eutrophication and maintaining ecological balance.