KOESSLARN Wastewater Treatment Plant, Kößlarn, Bavaria

KOESSLARN is a wastewater treatment plant located in Malgertsham, near Kößlarn, in the Landkreis Passau district of Bavaria, Germany. The plant serves a population of approximately 2,167 residents and operates with advanced treatment technology, ensuring high-quality effluent standards. As an advanced treatment facility, KOESSLARN goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, which is typical for plants in sensitive catchment areas under the EU Urban Waste Water Treatment Directive (91/271/EEC). The plant has a designed capacity of 2,500 cubic meters per day and currently treats an average daily flow of 548.42 cubic meters, indicating ample reserve capacity. The treated effluent is discharged into local watercourses that ultimately drain into the Danube River basin. The Danube is a major European river that flows into the Black Sea, supporting diverse aquatic ecosystems along its course. The advanced treatment helps protect downstream water quality and ecological health.

The plant discharges into small streams that feed into the Rott River, a tributary of the Inn River, which joins the Danube near Passau. The Danube basin is ecologically significant, supporting species such as sturgeon and various migratory fish. Advanced treatment at KOESSLARN reduces nutrient loading, helping to prevent eutrophication in downstream waters, including the Black Sea.