ZV Schwarzach Stulln Wastewater Treatment Plant, Wölsendorf, Bavaria

ZV Schwarzach Stulln is a wastewater treatment plant located in Wölsendorf, a district of Schwarzach bei Nabburg in the Bavarian region of Germany. The plant serves a population of around 3,036 people, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). As a German plant serving fewer than 10,000 population equivalents, it is subject to national regulations implementing the EU UWWTD, which requires appropriate treatment to protect receiving waters. Plants of this scale typically employ secondary biological treatment to meet effluent standards. The plant discharges treated wastewater into the local water system, which ultimately drains into the Schwarzach River, a tributary of the Naab River, then into the Danube River basin. The Danube flows into the Black Sea, making this plant part of a large international watershed. The surrounding region is characterized by mixed agricultural and forested landscapes, with the plant playing a role in maintaining local water quality.

The plant's treated effluent enters the Schwarzach River, a tributary of the Naab, which flows into the Danube River and eventually reaches the Black Sea. This watershed supports diverse aquatic life, including fish species such as barbel and chub, and is an important corridor for migratory birds. The plant's operations help protect downstream ecosystems from nutrient pollution and organic load.