Mlynary Wastewater Treatment Plant, Młynary, Poland - Secondary Treatment Facility

The Mlynary wastewater treatment plant is located in the town of Młynary, within the Warmian-Masurian Voivodeship of northern Poland. This facility serves a population of approximately 4,663 residents, classifying it as a small to medium agglomeration under Polish and EU regulations. The plant is situated inland, more than 10 km from the Baltic Sea coast, but within 50 km of the coast. The plant operates with secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The designed capacity of 13,925 m³/day indicates that the plant has significant headroom for future growth or seasonal variations. The actual discharge volume is 664.87 m³/day, suggesting a utilization rate well below capacity. The treated effluent is discharged into local watercourses that ultimately drain into the Baltic Sea via the Vistula Lagoon or directly into the Gulf of Gdańsk. The region's watershed supports diverse aquatic ecosystems and is part of the broader Baltic Sea catchment, which is sensitive to nutrient pollution. The plant's secondary treatment helps reduce organic load and nutrients, contributing to the protection of downstream water quality.

The plant discharges into local streams that flow toward the Vistula Lagoon, a coastal lagoon connected to the Baltic Sea. This lagoon is ecologically sensitive, supporting diverse fish and bird populations, and is subject to eutrophication risks from nutrient inputs. The Baltic Sea itself is a semi-enclosed sea with limited water exchange, making it vulnerable to pollution. The plant's secondary treatment helps mitigate nutrient and organic pollution, aligning with regional efforts to improve Baltic Sea health.