Mogielnica Wastewater Treatment Plant - Mazowieckie, Poland

The Mogielnica wastewater treatment plant is located in the town of Mogielnica, in the Mazowieckie province of Poland. It serves a population of 6,777 people, classifying it as a small to medium agglomeration under Polish and EU regulations. The plant provides secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive for inland freshwater discharges. As a secondary treatment facility, the plant removes organic matter and suspended solids through biological processes. Its designed capacity of 31,000 m³/day significantly exceeds the current discharge volume of 966.29 m³/day, indicating ample headroom for future growth. The plant operates under Poland's implementation of the EU Urban Waste Water Treatment Directive, which mandates secondary treatment for agglomerations above 2,000 population equivalent in freshwater areas. The treated effluent is discharged into local watercourses that eventually drain into the Vistula River basin, which flows northward into the Baltic Sea. The plant plays a key role in protecting the region's surface waters from nutrient pollution and organic loading, supporting aquatic life and downstream water quality in the Vistula catchment.

The plant discharges into local streams that are part of the Vistula River basin, Poland's largest river system. The Vistula flows through central Poland and empties into the Baltic Sea via the Gdańsk Bay. The watershed supports diverse aquatic habitats and is important for migratory fish species. Secondary treatment helps reduce biochemical oxygen demand and suspended solids, mitigating eutrophication risks in the Baltic Sea.