Haidmühle Wastewater Treatment Plant, Bavaria, Germany

The Haidmühle wastewater treatment plant is located in the Bavarian village of Haidmühle, in the Freyung-Grafenau district near the border with the Czech Republic. This facility serves a small population of 2,315 residents, typical of a rural agglomeration in southeastern Germany. The plant provides secondary treatment, which meets the minimum standard required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 4,000 m³/day and an average discharge volume of 990 m³/day, the plant operates well below its capacity, indicating room for future growth. The treated effluent is discharged into local watercourses that eventually drain into the Danube River basin, contributing to the Black Sea catchment. The plant plays a key role in protecting the region's streams and groundwater from untreated sewage, supporting the ecological health of the Bavarian Forest area.

The plant's discharge enters small streams in the Bavarian Forest, a low mountain range known for its dense woodlands and headwater streams. These waters flow into the Ilz River, a tributary of the Danube, which ultimately reaches the Black Sea. The region supports diverse aquatic life, including native fish species such as brown trout and grayling, and the plant's secondary treatment helps maintain water quality in this sensitive upland ecosystem.