RIELLS I VIABREA Wastewater Treatment Plant, Can Salvà, Catalunya

RIELLS I VIABREA is a wastewater treatment plant located in Can Salvà, within the municipality of Riells i Viabrea, in the province of Girona, Catalunya, Spain. The plant serves a population of approximately 2,019 people, classifying it as a small agglomeration under Spanish and EU regulations. The plant provides 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 designed capacity of 8,640 m³/day indicates the plant is sized to handle peak flows, though the reported discharge volume of 934.52 m³/day suggests current loading is well below capacity. The treated effluent is discharged into the local watershed, which ultimately drains into the Mediterranean Sea via the Tordera River basin. The plant's location within 50 km of the coast places it in a region where nutrient removal may be required to protect coastal water quality, though specific requirements depend on the sensitivity of the receiving waters.

The plant discharges into the Tordera River basin, which flows into the Mediterranean Sea near Blanes. The Tordera is a seasonal river that supports diverse aquatic life and is an important corridor for migratory fish. The downstream coastal area includes ecologically sensitive habitats such as seagrass meadows and sandy beaches that benefit from controlled nutrient inputs. The plant's secondary treatment helps reduce organic pollution and protect these downstream ecosystems.