Schmidgaden Wastewater Treatment Plant, Säulnhof, Bavaria

The Schmidgaden wastewater treatment plant is located in Säulnhof, a locality in the municipality of Stulln, within the Landkreis Schwandorf district of Bavaria, Germany. It served a population of 1,743 people before its operational status was listed as closed. The plant was designed with a capacity of 3,230 m³/day and had a discharge volume of 441.11 m³/day. As a secondary treatment facility, Schmidgaden provided biological treatment to remove organic matter and suspended solids. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), agglomerations with a population equivalent (PE) between 2,000 and 10,000 are generally required to have secondary treatment. Although this plant served fewer than 2,000 people, it still met secondary treatment standards, reflecting Germany's stringent implementation of the directive. The plant's treated effluent was discharged into local water bodies within the Danube River basin. The region is characterized by a mix of agricultural and forested areas, with the Naab River and its tributaries flowing through the landscape. The plant's operations contributed to protecting the water quality of these streams, which ultimately drain into the Danube and the Black Sea. More centralized facility in the area.

The treated wastewater from Schmidgaden entered local streams within the Naab River catchment, a tributary of the Danube River. The Danube flows through Central and Eastern Europe before emptying into the Black Sea. The region supports diverse aquatic life, including fish species such as brown trout and grayling, and the water quality is important for downstream ecosystems and human use. The plant's secondary treatment helped reduce nutrient and organic loads, mitigating eutrophication risks in receiving waters.