OS Zakrzewo Wastewater Treatment Plant, Podróżna, Poland

OS Zakrzewo is a wastewater treatment plant located in Podróżna, within the gmina Krajenka, powiat złotowski, województwo wielkopolskie, Poland. The plant serves a population of 1,168 and is part of the municipal infrastructure for the region. The plant provides secondary treatment, which is the standard required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 2000 m³/day and an actual discharge volume of 166.54 m³/day, the plant operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local watercourses that ultimately drain into the Baltic Sea via the Noteć River and the Oder River basin. The plant plays a key role in protecting the local watershed from nutrient pollution, supporting aquatic life in downstream rivers and the Baltic Sea ecosystem.

The plant discharges into the Noteć River catchment, which flows into the Warta River and then the Oder River, eventually reaching the Baltic Sea. The Baltic Sea is a semi-enclosed sea sensitive to eutrophication from nutrient inputs. The plant's secondary treatment helps reduce organic load and nutrients, contributing to the health of downstream aquatic ecosystems and the coastal marine environment.