UWWTP Troyan - Municipal Wastewater Treatment Plant in Lovech Province, Bulgaria

UWWTP Troyan is a municipal wastewater treatment plant located near the village of Kaleytsa in Troyan Municipality, Lovech Province, Bulgaria. The plant serves a population equivalent of approximately 28,133, placing it within the medium agglomeration category under EU regulations. It is situated inland, away from coastal areas, and discharges into local watercourses that ultimately drain into the Danube River basin. As a Bulgarian facility, the plant operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. The directive also mandates more advanced treatment if the receiving waters are designated as sensitive areas. Bulgaria has transposed these requirements into national legislation, and the plant is subject to permits issued by the Ministry of Environment and Water. The treated effluent from UWWTP Troyan is discharged into the Osam River or its tributaries, which flow northward into the Danube River and eventually the Black Sea. The local watershed supports diverse aquatic life and is part of the larger Danube basin, an ecologically significant region. The plant plays a key role in protecting water quality in this inland river system.

UWWTP Troyan discharges into the Osam River basin, a tributary of the Danube River. The Danube flows into the Black Sea, making this plant part of a transboundary watershed. The Osam River supports diverse freshwater species and is an important corridor for migratory fish. The Black Sea is a semi-enclosed sea with sensitive ecosystems, and nutrient pollution from upstream sources can contribute to eutrophication. The plant's treatment helps mitigate such impacts.