Kolno Wastewater Treatment Plant: Serving Kolno, Podlaskie, Poland

The Kolno wastewater treatment plant is a municipal facility located in northeastern Poland, serving the town of Kolno in Podlaskie Voivodeship. With a population equivalent of 9,106, it is classified as a medium-sized agglomeration under Polish regulations, which transpose the EU Urban Waste Water Treatment Directive (91/271/EEC). The plant is situated near the Obwodnica Kolna road, in the Duże Łabno area, and its operations are managed by local municipal authorities. Under the EU Urban Waste Water Treatment Directive, agglomerations with a population equivalent between 2,000 and 15,000 are required to provide secondary treatment (biological treatment) as a minimum standard. For plants serving populations above 10,000 in sensitive areas, more stringent treatment may be required. The Kolno plant is expected to comply with these standards, ensuring that effluent meets quality criteria before discharge. The treated wastewater from the Kolno plant is discharged into local watercourses that eventually flow into the Narew River, a major tributary of the Vistula River, which drains into the Baltic Sea. The Narew River basin supports diverse aquatic ecosystems and is an important ecological corridor in northeastern Poland. The plant plays a key role in protecting these waters from nutrient pollution and organic load.

The Kolno plant discharges into local streams that feed into the Narew River, a significant waterway in northeastern Poland. The Narew River flows into the Vistula River, which ultimately reaches the Baltic Sea. This watershed supports diverse aquatic life, including fish species such as pike and bream, and provides habitat for waterbirds. The plant's treatment helps reduce nutrient loading, which is critical for preventing eutrophication in downstream waters, including the Baltic Sea, which is sensitive to nitrogen and phosphorus pollution.