zKA Grossdubrau Wastewater Treatment Plant, Crosta, Sachsen, Germany

zKA Grossdubrau is a municipal wastewater treatment plant located in Crosta (Chróst), part of Großdubrau in the Bautzen district of Sachsen, Germany. The plant serves a population of approximately 2,500 and has a designed capacity of 3,000 m³/day, with a current discharge volume of 450 m³/day. As an advanced treatment facility, zKA Grossdubrau goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, meeting stringent German and EU standards. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), plants serving agglomerations between 2,000 and 10,000 population equivalent are required to have appropriate treatment; advanced treatment is typical in sensitive catchment areas like those draining into the Baltic Sea. The treated effluent from the plant is discharged into local streams that flow into the Spree River, which eventually drains into the North Sea via the Havel and Elbe rivers. The plant plays a key role in protecting the water quality of the Spree basin, which supports diverse aquatic life and is used for recreation and drinking water supply downstream.

The plant's discharge enters small watercourses in the Spree River basin, which flows through eastern Germany before joining the Havel and then the Elbe River, ultimately reaching the North Sea. The region's watershed is ecologically sensitive, supporting species such as the European otter and various migratory fish. Advanced treatment helps reduce nutrient loading, which is critical for preventing eutrophication in downstream lakes and coastal waters.