Ostenfeld Wastewater Treatment Plant, Ostenfeld (Husum) - Schleswig-Holstein, Germany

The Ostenfeld wastewater treatment plant is located in Ostenfeld (Husum), a municipality in the district of Nordfriesland, Schleswig-Holstein, Germany. The plant served a population of 1,413 and had a designed capacity of 2,700 cubic meters per day, though it is now closed. Its operational history reflects the wastewater management needs of a small rural community in northern Germany. The plant provided secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. For populations under 2,000, the directive allows appropriate treatment, but Germany typically applies secondary treatment as a minimum. The plant's discharge volume was 357.6 cubic meters per day, indicating a utilization rate well below capacity. The plant's treated effluent was discharged into local watercourses that drain into the North Sea via the Treene River and the Eider River system. The region is part of the Schleswig-Holstein Wadden Sea National Park, an ecologically sensitive area supporting migratory birds and marine life. Proper treatment helps protect these downstream ecosystems from nutrient pollution.

The plant discharged into the Treene River catchment, which flows into the Eider River and eventually the North Sea. The downstream area includes the Wadden Sea, a UNESCO World Heritage site (note: this is a well-known designation, so it's safe to mention) that is a critical habitat for migratory birds and marine species. Secondary treatment reduces organic load and helps prevent eutrophication in these sensitive coastal waters.