Lesna Wastewater Treatment Plant, Tarnowskie Gory, Poland

Lesna is a wastewater treatment plant located in Tarnowskie Gory, within the Slaskie Voivodeship of Poland. It serves a population of approximately 4,196 residents, classifying it as a small agglomeration under Polish and EU regulations. The plant is situated in the Upper Silesian metropolitan area, an industrial and urban region. The plant provides secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Its designed capacity is 8,000 m³ per day, and it currently discharges an average of 598.28 m³ per day, indicating significant spare capacity. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent is discharged into local watercourses that ultimately drain into the Vistula River basin and then to the Baltic Sea. The plant plays a key role in protecting the region's water quality, particularly given the industrial legacy of Upper Silesia. Its operation supports the ecological health of downstream rivers and the Baltic Sea coastal zone.

The plant discharges into the local drainage network that feeds the Vistula River, Poland's largest river, which flows into the Baltic Sea. The Vistula basin supports diverse aquatic life and is an important migratory corridor for fish. The region's industrial history means that effective wastewater treatment is critical to prevent nutrient and pollutant loading in the Baltic Sea, which is sensitive to eutrophication.