Mieleszyn Wastewater Treatment Plant, Bielawy, Poland

The Mieleszyn wastewater treatment plant is located in Bielawy, within the gmina Janowiec Wielkopolski in województwo kujawsko-pomorskie, Poland. It serves a population of 807, classifying it as a small agglomeration under Polish and EU regulations. The plant operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. The plant has a designed capacity of 423.00 m³/day and currently discharges 115.07 m³/day of treated wastewater. It provides secondary treatment, which is the standard level for inland plants serving small communities under the directive. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent is discharged into local water bodies that eventually drain into the Baltic Sea via the Vistula or Oder river basins. The plant's location inland, away from the coast, reduces direct marine impact. Its operation helps protect local streams and groundwater from untreated sewage, supporting aquatic life and downstream ecosystems.

The plant discharges into local watercourses that are part of the Vistula River basin, which flows northward into the Baltic Sea. The region's watershed supports diverse aquatic habitats and is important for migratory fish species. The secondary treatment provided by the plant reduces organic pollution and nutrient loads, helping to maintain water quality in downstream rivers and ultimately contributing to the health of the Baltic Sea ecosystem.