Wierzbno Wastewater Treatment Plant, dolnośląskie Province, Poland

The Wierzbno wastewater treatment plant is located in the village of Wierzbno, within gmina Domaniów, powiat oławski, in the dolnośląskie province of Poland. This facility serves a small population of 1,068 residents, reflecting its role in a rural community. The plant is situated inland, away from coastal areas, and operates as part of Poland's municipal wastewater infrastructure. The plant provides secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The directive mandates secondary treatment for all discharges from agglomerations with a population equivalent (PE) between 2,000 and 10,000, and Wierzbno's population of 1,068 falls below this threshold, yet the plant still meets secondary treatment standards. The designed capacity of 4,400 m³/day indicates the plant's potential to handle higher loads, while the current discharge volume of 152.28 m³/day suggests ample reserve capacity. The treated effluent from Wierzbno is discharged into local watercourses that ultimately drain into the Oder River basin, which flows northward to the Baltic Sea. The plant's operation helps protect the Oder River and its tributaries from untreated sewage, supporting aquatic life and water quality in the region. As part of Poland's compliance with EU water directives, the plant contributes to the protection of the Baltic Sea from nutrient pollution.

The Wierzbno plant discharges into local streams that are part of the Oder River basin. The Oder River flows through Poland and Germany before reaching the Baltic Sea, a semi-enclosed sea sensitive to eutrophication from nutrient inputs. The plant's secondary treatment reduces organic pollutants and suspended solids, helping to maintain water quality in the Oder basin and ultimately contributing to the ecological health of the Baltic Sea.