Fridolfing Wastewater Treatment Plant: Advanced Treatment in Bayern, Germany

The Fridolfing wastewater treatment plant is located in the municipality of Fridolfing, in the Landkreis Traunstein district of Bayern, Germany. It serves a population of approximately 4,500, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). The plant is situated inland, away from coastal areas. The facility 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 water bodies. The plant has a designed capacity of 3,450 m³/day and currently discharges an average volume of 872 m³/day, indicating it operates well below its capacity. The treated effluent is discharged into a local watercourse that ultimately drains into the Salzach River, a tributary of the Inn River, which flows into the Danube and eventually reaches the Black Sea. The plant's advanced treatment helps protect the downstream aquatic ecosystem, particularly in the Danube basin, which is ecologically significant for its biodiversity and migratory fish species.

The plant discharges into a local stream that feeds into the Salzach River, a major tributary of the Inn River. The Inn flows into the Danube, which drains into the Black Sea. The Danube basin is one of Europe's most important ecological corridors, supporting diverse aquatic life and migratory fish species. Advanced treatment at this plant helps reduce nutrient loading, protecting downstream water quality in this sensitive river system.