Grossenwiehe Wastewater Treatment Plant, Lüngerau, Schleswig-Holstein

The Grossenwiehe wastewater treatment plant is located in Lüngerau, a locality within the municipality of Großenwiehe in the district of Schleswig-Flensburg, Schleswig-Holstein, Germany. The plant serves a population equivalent of 3,962, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU UWWTD for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. The plant has a designed capacity of 4,670 m³/day and currently discharges 543.46 m³/day of treated wastewater. The treated effluent is discharged into local watercourses that eventually drain into the North Sea via the Treene River and the Eider River system. The region's water bodies support diverse aquatic life and are important for migratory fish species. The advanced treatment helps minimize nutrient loading, which is critical for preventing eutrophication in downstream coastal waters.

The plant discharges into small streams that flow into the Treene River, a tributary of the Eider River, which ultimately reaches the North Sea. The North Sea coast is ecologically sensitive, supporting important bird populations and marine habitats. Advanced treatment at this plant reduces nitrogen and phosphorus loads, helping to protect downstream waters from eutrophication and algal blooms.