Perlesreut Wastewater Treatment Plant, Bavaria, Germany

Perlesreut wastewater treatment plant is located in the municipality of Perlesreut, in the Bavarian district of Freyung-Grafenau, Germany. It served a population of approximately 1,908 people, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). The plant is currently closed. As a secondary treatment facility, the plant provided biological treatment to reduce organic matter and suspended solids. For small agglomerations in Germany, secondary treatment is the standard requirement under the EU UWWTD, which mandates such treatment for all inland plants serving between 2,000 and 10,000 population equivalents. The plant's designed capacity was 4,500 m³/day, with an average discharge volume of 482.87 m³/day. The treated effluent was discharged into a local watercourse within the Danube River basin. The Danube flows southeast through Central and Eastern Europe before emptying into the Black Sea. The plant's operation contributed to protecting the water quality of the receiving stream and downstream ecosystems, including the Danube's diverse aquatic habitats and the Black Sea's marine environment.

The plant discharged into a small tributary of the Danube River, which ultimately flows into the Black Sea. The Danube basin supports a wide range of aquatic species, including migratory fish such as sturgeon. The plant's secondary treatment helped reduce nutrient loads, mitigating eutrophication risks in the downstream river and coastal waters.