Stare Siolkowice Wastewater Treatment Plant - Karłowice, Opole Voivodeship, Poland

Stare Siolkowice is a wastewater treatment plant located in Karłowice, a village in the Opole Voivodeship of southwestern Poland. The facility serves a population of approximately 2,037 residents and is part of the municipal infrastructure managed by the local gmina (Popielów). The plant is situated in a rural area near the Odra River basin. The plant employs advanced treatment processes, which go beyond the secondary treatment standards required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 5,340 m³/day and a current discharge volume of 290.44 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local watercourses that ultimately drain into the Odra River, a major river flowing through Poland and into the Baltic Sea. The advanced treatment ensures high-quality effluent, protecting the sensitive aquatic ecosystems of the Odra basin and contributing to the overall health of the Baltic Sea environment.

The plant discharges into the Odra River basin, which flows through western Poland and forms part of the border with Germany before emptying into the Szczecin Lagoon and the Baltic Sea. The Odra supports diverse aquatic life and is an important ecological corridor for migratory fish. The advanced treatment level helps minimize nutrient loading, which is critical for preventing eutrophication in the Baltic Sea, a sensitive marine environment.