Straden Puxa Wastewater Treatment Plant, Sulzbach, Steiermark, Austria

Straden Puxa is an advanced wastewater treatment plant located in Sulzbach, a locality within the municipality of Straden in the Bezirk Südoststeiermark, Steiermark, Austria. The plant serves a population of 1,727 and has a designed capacity of 3,100 m³ per day, with an average discharge volume of 462.21 m³ per day. As an advanced treatment facility, Straden Puxa provides tertiary-level treatment, which includes nutrient removal and disinfection beyond secondary biological processes. This level of treatment is typical for plants in sensitive areas under the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires advanced treatment for agglomerations discharging into sensitive water bodies. The treated effluent from the plant is discharged into local watercourses that drain into the Mur River, a major tributary of the Drava River, which ultimately flows into the Danube River and the Black Sea. The plant plays a key role in protecting the water quality of the Mur basin, supporting aquatic ecosystems and downstream water uses.

The plant discharges into the Mur River basin, which flows through Steiermark and into Slovenia and Croatia before joining the Drava River. The Mur River supports diverse aquatic life, including fish species such as grayling and brown trout, and is an important migratory corridor. The advanced treatment at Straden Puxa helps reduce nutrient loads, protecting downstream water quality in the Danube River and the Black Sea.