Wierszyno Wastewater Treatment Plant - Secondary Treatment, Pomerania, Poland

The Wierszyno wastewater treatment plant is located in the village of Wierszyno, within gmina Kołczygłowy, powiat bytowski, in the województwo pomorskie region of northern Poland. The facility serves a population of 2,113 and operates with secondary treatment, which is the standard level required under Polish and EU regulations for small agglomerations. As a plant serving fewer than 10,000 people, Wierszyno falls under the EU Urban Waste Water Treatment Directive (91/271/EEC) category for smaller agglomerations, where secondary treatment is generally sufficient unless the receiving waters are designated as sensitive areas. The plant's designed capacity of 2,900 m³/day indicates it has room to accommodate future growth or seasonal variations. The treated effluent from Wierszyno is discharged into local watercourses that ultimately drain into the Baltic Sea via the Słupia River basin. The Pomeranian region features numerous small rivers and lakes that support diverse aquatic life and are important for regional biodiversity. Proper wastewater treatment helps protect these ecosystems from nutrient pollution and eutrophication.

The Wierszyno plant discharges into small streams that feed into the Słupia River, which flows northward into the Baltic Sea. The Baltic Sea is a brackish, semi-enclosed sea sensitive to nutrient loading, where excess nitrogen and phosphorus from wastewater can contribute to algal blooms and oxygen depletion. The Pomeranian region's aquatic habitats support fish species such as salmon and trout, as well as migratory birds, making effective treatment crucial for maintaining ecological balance.