PS 500 Wastewater Treatment Plant, Tarnowa, Wielkopolskie, Poland

PS 500 is a municipal wastewater treatment plant located in Tarnowa, within the Wielkopolskie Voivodeship of Poland. The facility serves a population of 2,430 and operates under Poland's implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 4,333 m³/day and an actual discharge volume of 346.48 m³/day, the plant operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into a local watercourse that eventually drains into the Warta River basin, part of the Oder River system flowing into the Baltic Sea. The plant plays a key role in protecting local water quality and supporting the ecological health of the region's rivers and downstream environments.

The plant's discharge enters a tributary of the Warta River, which flows into the Oder River and ultimately reaches the Baltic Sea. This watershed supports diverse aquatic life and is important for regional biodiversity. The secondary treatment helps reduce nutrient loads, mitigating eutrophication risks in the Baltic Sea, a sensitive marine environment.