Seth Wastewater Treatment Plant, Schleswig-Holstein, Germany

Seth wastewater treatment plant is located in the municipality of Seth, in the district of Segeberg, Schleswig-Holstein, Germany. The plant served a population of approximately 1,977 people and was designed with a capacity of 2,600 m³/day. It is now closed and no longer operational. The plant provided advanced treatment, which goes beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal to protect sensitive water bodies. The plant's discharge volume was recorded at 500.33 m³/day. The treated effluent from the plant would have discharged into local watercourses that flow into the Alster river, which eventually reaches the Elbe river and the North Sea. The region is characterized by agricultural land and small settlements, and the plant's advanced treatment helped protect downstream aquatic ecosystems from nutrient pollution.

The plant's discharge would have entered small streams in the Alster river basin, which flows into the Elbe river and ultimately the North Sea. The Alster and Elbe support diverse aquatic life and are important for migratory fish. Advanced treatment at this plant helped reduce nutrient loads, protecting downstream waters from eutrophication.