Choczewo Wastewater Treatment Plant, Żelazno, Poland - Secondary Treatment Near Baltic Coast

The Choczewo wastewater treatment plant is located in the village of Żelazno, within the Gmina Choczewo in the Wejherowo County of Pomeranian Voivodeship, Poland. It serves a population of approximately 1,178 residents, making it a small-scale municipal facility. The plant is situated in a rural area near the Baltic Sea coast, less than 10 kilometers from the shoreline. As a secondary treatment plant, Choczewo meets the minimum treatment standards required under Polish law, which transposes the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations with a population equivalent (PE) below 2,000, secondary treatment is typically sufficient unless the receiving waters are designated as sensitive areas. The plant's designed capacity is 5,720 cubic meters per day, and the current discharge volume is 167.96 cubic meters per day, indicating ample reserve capacity. The treated effluent is discharged into local watercourses that eventually drain into the Baltic Sea. The Baltic Sea is a brackish inland sea with limited water exchange, making it sensitive to nutrient pollution. The plant's secondary treatment helps reduce organic load and suspended solids, contributing to the protection of coastal ecosystems and supporting the ecological health of the region's rivers and the Baltic Sea.

The plant discharges into small streams that flow into the Baltic Sea, a semi-enclosed sea with high ecological sensitivity due to its brackish water and limited circulation. Nutrient inputs from wastewater can contribute to eutrophication, affecting marine life and coastal habitats. The facility's secondary treatment reduces biochemical oxygen demand and suspended solids, helping to mitigate these impacts in the local watershed and downstream coastal environment.