Attersee Wastewater Treatment Plant, Oberachmann, Austria

The Attersee wastewater treatment plant is located in Oberachmann, a locality in the municipality of Lenzing an der Ager, in the Bezirk Vöcklabruck district of Upper Austria (Oberösterreich). The plant serves a population equivalent of 42,802, placing it in the medium agglomeration category under EU classification. As a plant in Austria, a European Union member state, Attersee is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations between 10,000 and 100,000 population equivalent, the directive requires secondary treatment (biological treatment) as a minimum standard. The plant's treatment process is designed to meet these regulatory requirements, ensuring that effluent quality standards are maintained. The treated wastewater from the Attersee plant is discharged into the local water environment, which ultimately drains into the Ager River. The Ager flows into the Traun River, a tributary of the Danube, which carries water to the Black Sea. The plant plays a key role in protecting the water quality of the Ager and downstream ecosystems, including the Danube River basin.

The Attersee plant discharges into the Ager River, which flows into the Traun River and then the Danube, eventually reaching the Black Sea. The local watershed includes the Attersee lake region, an ecologically sensitive area that supports diverse aquatic life and serves as an important habitat for fish and bird species. The plant's treatment helps maintain water quality in this recreational and ecological area.