Walsdorf Wastewater Treatment Plant, Erlau, Bavaria

The Walsdorf wastewater treatment plant is located in Erlau, within the Landkreis Bamberg district of Bavaria, Germany. It serves a population of approximately 2,656 people, placing it in the small agglomeration category under the EU Urban Waste Water Treatment Directive (UWWTD). The plant is situated inland, far from coastal waters, and operates under Germany's stringent national water quality standards. The facility employs advanced treatment processes, which go beyond the secondary treatment 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 3,200 m³/day and currently discharges an average of 749.61 m³/day, indicating significant spare capacity for future growth. The treated effluent from Walsdorf is discharged into local watercourses that eventually drain into the Main River, a major tributary of the Rhine. The Rhine basin is one of Europe's most important river systems, supporting diverse aquatic life and providing drinking water for millions. The advanced treatment at Walsdorf helps reduce nutrient loads that could otherwise contribute to eutrophication in downstream lakes and the North Sea.

The plant discharges into small streams that flow into the Regnitz River, a tributary of the Main River, which ultimately drains into the Rhine and the North Sea. The region is part of the Upper Rhine basin, an ecologically sensitive area that supports diverse aquatic habitats and migratory fish species. Advanced treatment at Walsdorf helps protect downstream water quality, particularly by reducing nutrient inputs that could fuel algal blooms in the North Sea.