UWWTP Veliki Otok - Secondary Wastewater Treatment Plant in Postojna, Slovenia

UWWTP Veliki Otok is a municipal wastewater treatment plant located in the Veliki Otok industrial zone near Postojna, Slovenia. The plant serves the local community and operates under Slovenia's implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this scale. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. The facility manages wastewater from the Postojna area. As part of the EU regulatory framework, the plant must meet effluent quality standards for biochemical oxygen demand, chemical oxygen demand, and total suspended solids. The treated effluent is discharged into the local water system, which ultimately drains into the Adriatic Sea via the Pivka River and the Ljubljanica River basin. The plant plays a key role in protecting downstream water quality and supporting the ecological health of the region's karst landscape and groundwater resources.

The plant discharges into the Pivka River, a karst river that feeds into the Ljubljanica River system, which flows into the Sava River and eventually reaches the Adriatic Sea. The region is characterized by sensitive karst aquifers and diverse aquatic habitats. Protecting water quality is critical for maintaining the ecological balance of the subterranean and surface water networks that support local biodiversity.