Drohiczyn Wastewater Treatment Plant, Czepielin, Mazowieckie, Poland

The Drohiczyn wastewater treatment plant is located in Czepielin, a village in the Mazowieckie Voivodeship of Poland. It serves a small population of 481 residents, reflecting its role in a rural community. The plant operates under secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive for agglomerations of this size. As a secondary treatment facility, Drohiczyn removes organic matter and suspended solids through biological processes. The plant has a designed capacity of 2142 m³/day and currently treats 68.58 m³/day, indicating significant spare capacity. This suggests the plant is well-sized to accommodate future growth or seasonal variations. The treated effluent is discharged into the local watershed, which ultimately drains into the Bug River basin and then to the Narew River, a tributary of the Vistula. The Vistula flows into the Baltic Sea, making the plant part of a larger transboundary water system. Proper treatment helps protect downstream aquatic ecosystems and supports water quality in the region.

The plant discharges into the local catchment of the Bug River, a major tributary of the Narew River, which flows into the Vistula and eventually the Baltic Sea. This watershed supports diverse aquatic life and is an important ecological corridor in eastern Poland. Secondary treatment reduces organic pollution, helping to maintain water quality in this sensitive riverine environment.