Hennstedt Wastewater Treatment Plant, Schleswig-Holstein, Germany

The Hennstedt wastewater treatment plant is located in the municipality of Hennstedt, within the district of Dithmarschen in Schleswig-Holstein, Germany. It serves a population of approximately 3,645 people, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). The plant is situated inland, more than 10 km from the coast, and its operations are part of the region's water management infrastructure. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU UWWTD for agglomerations of this size. It has a designed capacity of 3,800 m³/day and currently discharges 381.69 m³/day of treated wastewater. This indicates that the plant operates well below its capacity, with room for future growth or seasonal variations. The treated effluent is discharged into local watercourses that eventually drain into the Eider River, a major river in Schleswig-Holstein that flows into the North Sea. The plant plays a key role in protecting the Eider basin and downstream coastal waters from nutrient pollution, supporting aquatic life and water quality in the region.

The plant discharges into the Eider River basin, which flows through Schleswig-Holstein and empties into the North Sea near Tönning. The Eider is an ecologically important river supporting diverse fish populations and migratory birds. Advanced treatment at this plant helps reduce nutrient loads, protecting the river's sensitive ecosystem and the downstream Wadden Sea, a critical habitat for marine life.