Marktgemeinde St Anna am Aigen Wastewater Treatment Plant, Sankt Anna am Aigen, Steiermark

Marktgemeinde St Anna am Aigen is an advanced wastewater treatment plant located in Sankt Anna am Aigen, a municipality in the district of Südoststeiermark in the Austrian state of Steiermark. The plant serves a population of approximately 1,513 residents, reflecting its role in managing domestic wastewater for this rural community. The plant employs advanced treatment processes, which go beyond secondary treatment to remove nutrients and other pollutants. With a designed capacity of 2,200 m³/day and a current discharge volume of 223.38 m³/day, the facility operates well within its capacity. As an Austrian plant, it complies with the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates appropriate treatment levels for agglomerations of this size. The treated effluent is discharged into local watercourses that ultimately drain into the Mur River, a major tributary of the Drava and Danube river systems. This connection to the Danube basin underscores the plant's role in protecting downstream water quality in the Black Sea catchment area.

The plant discharges into small streams that flow into the Mur River, which joins the Drava near Legrad, Croatia, and eventually reaches the Danube. The Mur River supports diverse aquatic life and is an important migratory corridor for fish species. The advanced treatment helps reduce nutrient loading, protecting the ecological health of these waters.