Grodzisko Dolne Wastewater Treatment Plant - Podkarpackie, Poland

Grodzisko Dolne wastewater treatment plant is located in the village of Grodzisko Dolne, within the Podkarpackie Voivodeship in southeastern Poland. The facility serves a population of 2,178, classifying it as a small agglomeration under Polish and EU regulations. The plant is situated in a rural area near the San River basin. The plant provides secondary treatment, which is the minimum required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. It has a designed capacity of 5,792 m³/day and currently discharges 310.55 m³/day of treated wastewater. The treatment process involves biological degradation to reduce organic matter and suspended solids before discharge. The treated effluent is released into local watercourses that eventually drain into the San River, a tributary of the Vistula River, which flows into the Baltic Sea. The plant plays a key role in protecting the local watershed from nutrient pollution and safeguarding aquatic ecosystems in the region.

The plant discharges into small streams that feed the San River, part of the Vistula River basin, which ultimately reaches the Baltic Sea. The surrounding area is predominantly agricultural, so the plant helps reduce nutrient loading that could otherwise contribute to eutrophication in downstream water bodies. The San River supports diverse fish populations and is an important ecological corridor in southeastern Poland.