KPU Rupe Wastewater Treatment Plant, Alsviķu pagasts, Latvia

KPU Rupe is a wastewater treatment plant located in Alsviķu pagasts, Alūksnes novads, Latvia. It serves a population of 1,381, classifying it as a small agglomeration under EU regulations. The plant operates secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for freshwater discharges from agglomerations of this size. The plant has a designed capacity of 1,500 m³/day and currently treats an average of 720.80 m³/day, indicating operational headroom. As a secondary treatment facility, it removes organic matter and suspended solids but does not include advanced nutrient removal. Under the EU UWWTD, secondary treatment is sufficient for discharges to freshwater bodies in non-sensitive areas. The treated effluent is discharged into local surface waters within the Gauja River basin, which flows into the Baltic Sea. The Gauja River is an ecologically significant watercourse supporting diverse aquatic life and providing important habitat for fish species. The plant's location inland, more than 50 km from the coast, reduces direct marine impact.

The plant discharges into the Gauja River basin, which drains into the Baltic Sea via the Daugava River. The Gauja River is a key ecological corridor in Latvia, supporting diverse fish populations and riparian ecosystems. The Baltic Sea is a semi-enclosed brackish sea sensitive to nutrient pollution, making effective wastewater treatment crucial for reducing eutrophication risks.