STIEFENHOFEN Wastewater Treatment Plant, Oberthalhofen, Bayern, Germany

STIEFENHOFEN is a former wastewater treatment plant located in Oberthalhofen, a locality within the municipality of Stiefenhofen in the Landkreis Lindau district of Bayern, Germany. The plant served a population of 1,780 people and was designed with a capacity of 2,375 m³/day, with an average discharge volume of 450.48 m³/day. It is currently listed as closed. As an advanced treatment facility, STIEFENHOFEN would have met the stringent requirements of the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates advanced (tertiary) treatment for discharges into sensitive areas. For a small agglomeration of this size, the directive requires at least secondary treatment, but the plant exceeded this standard with advanced treatment. The plant's discharge would have entered local watercourses in the catchment of the Leiblach River, which flows into Lake Constance (Bodensee) and ultimately into the Rhine River. The region is ecologically sensitive, supporting diverse aquatic life and serving as an important corridor for migratory fish. The closure of the plant suggests that wastewater from this area is now treated at a larger, regional facility.

The plant discharged into the Leiblach River catchment, which flows into Lake Constance (Bodensee), a large alpine lake shared by Germany, Austria, and Switzerland. Lake Constance is a critical drinking water reservoir and supports a rich ecosystem, including endemic fish species and migratory birds. The Rhine River, which drains Lake Constance, flows through several countries to the North Sea, making the watershed ecologically significant on a continental scale.