Miejska Oczyszczalnia Sciekow w Zelechowie - Secondary Wastewater Treatment in Żelechów, Poland

Miejska Oczyszczalnia Sciekow w Zelechowie is a municipal wastewater treatment plant located in Żelechów, in the Mazowieckie Voivodeship of Poland. The plant serves a population of approximately 4,688 residents, making it a small agglomeration under Polish and EU classification. It is situated inland, away from coastal areas, and plays a key role in managing local wastewater. The plant provides secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 16,300 m³/day and a current discharge volume of 668.44 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The treatment process ensures that effluent meets regulatory standards before discharge. The treated wastewater is released into the local water system, which ultimately drains into the Vistula River basin, the largest river in Poland. The Vistula flows northward into the Baltic Sea, making the plant's operations important for protecting both local streams and the broader marine environment. Effective secondary treatment reduces organic pollutants and nutrients, helping to maintain ecological balance in the watershed.

The plant discharges into the Vistula River basin, which flows through central Poland and empties into the Baltic Sea. This watershed supports diverse aquatic life and is an important ecological corridor. The plant's secondary treatment helps reduce nutrient loads, mitigating eutrophication risks in downstream water bodies and the Baltic Sea.