Zwoleń Wastewater Treatment Plant | Mazowieckie, Poland

The Zwoleń wastewater treatment plant is located in the town of Zwoleń, within the Mazowieckie voivodeship of Poland. It serves a population of 4,353, classifying it as a small agglomeration under Polish and EU regulations. The plant provides secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for inland freshwater discharges from agglomerations of this size. The facility has a designed capacity of 2,500 m³/day and currently discharges an average of 620.67 m³/day of treated effluent. The treated wastewater is discharged into local waterways that ultimately drain into the Vistula River basin, Poland's largest river system. The Vistula flows northward into the Baltic Sea, making the plant's operations relevant to the ecological health of both the regional watershed and the Baltic marine environment.

The plant discharges into the Vistula River basin, which drains into the Baltic Sea via the Vistula Delta. The downstream environment includes ecologically sensitive areas such as the Vistula estuary, which supports diverse aquatic life and serves as an important migratory corridor for fish. The Baltic Sea is a brackish water body with limited water exchange, making it vulnerable to nutrient pollution from wastewater discharges.