Wertach Wastewater Treatment Plant, Oy-Mittelberg, Bavaria

The Wertach wastewater treatment plant is located in Oy-Mittelberg, a municipality in the Oberallgäu district of Bavaria, Germany. It serves a population of approximately 3,546 people, placing it in the small agglomeration category under the EU Urban Waste Water Treatment Directive (UWWTD). The plant is situated in a rural, alpine region near the border with Austria. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU UWWTD for agglomerations of this size. With a designed capacity of 7,500 m³/day and a current discharge volume of 911.45 m³/day, the plant operates well below its capacity, indicating room for future growth or seasonal fluctuations. As a German facility, it operates under the national Wasserhaushaltsgesetz (Water Resources Act) and must comply with strict effluent standards. The treated effluent is discharged into the local watershed, which ultimately drains into the Wertach River, a tributary of the Lech River, which flows into the Danube and then the Black Sea. The plant plays a key role in protecting the sensitive alpine streams and groundwater in the region, which support diverse aquatic life and are important for drinking water supply.

The Wertach plant discharges into the local watershed that feeds the Wertach River, a tributary of the Lech River. The Lech flows into the Danube, which ultimately reaches the Black Sea. The region is characterized by alpine streams and groundwater systems that are ecologically sensitive, supporting cold-water fish species and diverse macroinvertebrate communities. The advanced treatment helps minimize nutrient and pollutant loads to these waters.