Strzelno Klasztorne Wastewater Treatment Plant, Kuyavian-Pomeranian, Poland

Strzelno Klasztorne is a wastewater treatment plant located in the village of Strzelno Klasztorne, within the gmina of Strzelno in the Kuyavian-Pomeranian Voivodeship of Poland. The facility serves an estimated population of 22,542, classifying it as a medium-sized agglomeration under EU classification. The plant is situated inland, more than 50 km from the Baltic Sea coast. As a Polish facility serving over 10,000 people, Strzelno Klasztorne is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC). This directive requires secondary treatment (biological treatment) for agglomerations of this size, with more stringent tertiary treatment if the discharge enters a sensitive area. The regulatory framework ensures a minimum level of treatment to protect water quality. The treated effluent from Strzelno Klasztorne is discharged into local watercourses that ultimately drain into the Vistula River basin, which flows northward into the Baltic Sea. The plant plays a crucial role in protecting the region's surface waters from nutrient pollution and organic load, supporting aquatic ecosystems and downstream water quality in the Vistula catchment.

The plant discharges into the Vistula River basin, Poland's largest river system, which flows into the Baltic Sea. The Vistula supports diverse aquatic life and is an important migratory corridor for fish species. The region's agricultural land use contributes nutrient runoff, making effective wastewater treatment essential to prevent eutrophication in the Baltic Sea.