COV Piestany Wastewater Treatment Plant, Piešťany, Slovakia

COV Piestany is a municipal wastewater treatment plant located in Piešťany, Trnavský kraj, Slovakia. The facility serves a population of approximately 29,798, placing it in the medium agglomeration category under EU classification. As a plant of this scale in an EU member state, COV Piestany is required to meet secondary treatment standards under the Urban Waste Water Treatment Directive (91/271/EEC). The directive mandates that agglomerations with a population equivalent between 10,000 and 150,000 must have secondary treatment, with more stringent requirements if discharging into sensitive areas. The plant's treated effluent is discharged into the local watershed, which ultimately drains into the Váh River, a major tributary of the Danube River. The Danube then flows into the Black Sea, making this plant part of a large international river basin that supports diverse aquatic ecosystems and provides water for millions of people.

The plant discharges into the Váh River basin, which flows into the Danube River and ultimately reaches the Black Sea. This watershed supports diverse aquatic life and is an important ecological corridor in Central Europe. The region's water quality is influenced by agricultural runoff and urban development, making effective wastewater treatment critical for maintaining downstream ecosystem health.