Walchsee Wastewater Treatment Plant, Kössen, Tirol, Austria

The Walchsee wastewater treatment plant is located in Kössen, a municipality in the Bezirk Kitzbühel district of Tirol, Austria. It serves a population of approximately 6,511 people, classifying it as a small to medium agglomeration under EU regulations. The plant is situated in the Alpine region, which influences its operational and environmental context. As a facility in an EU member state, Walchsee is subject to the Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations of this size, the directive requires at least secondary treatment (biological treatment) to reduce organic matter and suspended solids. It is expected to meet these EU standards. The treated effluent from the plant is discharged into local watercourses that ultimately drain into the Inn River, a major tributary of the Danube. The Danube flows into the Black Sea, making this plant part of a large international river basin. The Alpine setting means the receiving waters are sensitive to nutrient inputs, and the plant plays a role in protecting downstream aquatic ecosystems.

The plant discharges into the local watershed that feeds the Inn River, which flows into the Danube and eventually the Black Sea. The Alpine streams in this region are ecologically sensitive, supporting diverse aquatic life including fish species such as brown trout. The plant's treatment helps prevent nutrient pollution that could harm these ecosystems.