ARA Zeller Becken Wastewater Treatment Plant, Zell am See, Salzburg, Austria

ARA Zeller Becken is a municipal wastewater treatment plant located in Zell am See, in the state of Salzburg, Austria. The plant serves a population of approximately 46,350 people, classifying it as a medium-sized agglomeration under EU regulations. It is situated in the Alpine region, near the shores of Lake Zell, a prominent water body in the area. As a plant serving over 10,000 population equivalents, ARA Zeller Becken is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment as a minimum. For discharges into sensitive areas like lakes, tertiary treatment (nutrient removal) is typically required to protect water quality. The plant's treatment processes are designed to meet these stringent standards, ensuring compliance with Austrian and EU regulations. The treated effluent from ARA Zeller Becken is discharged into the local watershed, which ultimately drains into the Salzach River and then the Inn River, a major tributary of the Danube. The receiving water bodies are ecologically sensitive, supporting diverse aquatic life and serving as important recreational areas. The plant plays a critical role in preserving the water quality of Lake Zell and the downstream river systems.

ARA Zeller Becken discharges into the local watershed that feeds Lake Zell (Zeller See), a glacial lake in the Austrian Alps. The lake drains via the Salzach River, which flows north to join the Inn River, a major Danube tributary. The region is ecologically sensitive, supporting cold-water fish species and serving as a habitat for aquatic biodiversity. Protecting water quality is essential for tourism and recreation in the Zell am See area.