TP 986 of Ylivieskan kt Wastewater Treatment Plant, Ylivieska, Finland

TP 986 of Ylivieskan kt is a municipal wastewater treatment plant located in Ylivieska, Pohjois-Pohjanmaa, Finland. It serves a population of approximately 11,000 residents, classifying it as a medium-sized agglomeration under EU classification. The plant is situated inland in the northern region of Finland, where cold climate conditions influence treatment operations. As a Finnish wastewater facility, the plant is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. Finnish national regulations further mandate nutrient removal (nitrogen and phosphorus) for plants in sensitive areas, which includes many inland water bodies. The plant's treatment process and capacity are designed to meet these stringent standards, ensuring compliance with both national and EU requirements. The treated effluent is discharged into local watercourses that eventually drain into the Gulf of Bothnia, part of the Baltic Sea. The Baltic Sea is a sensitive brackish water body with limited water exchange, making it vulnerable to eutrophication from nutrient inputs. The plant's nutrient removal plays a crucial role in protecting downstream aquatic ecosystems and supporting the ecological health of the region's rivers and coastal waters.

The plant discharges into local rivers that flow through the Kalajoki basin, eventually reaching the Gulf of Bothnia in the Baltic Sea. The Baltic Sea is a semi-enclosed, brackish sea with high ecological sensitivity to nutrient pollution, particularly nitrogen and phosphorus. Effective wastewater treatment at this plant helps reduce nutrient loads that could otherwise contribute to algal blooms and oxygen depletion in the coastal zone. The surrounding region features boreal forests and agricultural areas, where runoff management is also important for water quality.