ZKA Ostritz Wastewater Treatment Plant, Krzewina, Lower Silesia, Poland

ZKA Ostritz is a municipal wastewater treatment plant located in Krzewina, a village in the Lower Silesian Voivodeship of southwestern Poland. The plant serves a population of approximately 2,900 people and is situated near the border with Germany, reflecting the cross-border nature of the region's water management. The plant provides secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations with a population equivalent between 2,000 and 10,000. With a designed capacity of 5,000 m³/day and a current discharge volume of 375 m³/day, the plant operates well below its capacity, indicating potential for future growth or seasonal variations. The treated effluent from ZKA Ostritz is discharged into local watercourses that ultimately drain into the Lusatian Neisse River, a tributary of the Oder River. The Oder flows northward to the Baltic Sea, making the plant part of a transboundary river basin shared by Poland, Germany, and the Czech Republic. Proper treatment here helps protect the ecological health of the Lusatian Neisse and the broader Oder estuary.

ZKA Ostritz discharges into the Lusatian Neisse River, which flows into the Oder River and then to the Baltic Sea. The region is characterized by agricultural and forested landscapes, and the river supports diverse aquatic life. The plant's secondary treatment helps reduce nutrient loads, which is critical for preventing eutrophication in the Baltic Sea, a sensitive marine environment.