Santa Maria de Cayon Wastewater Treatment Plant, Saron, Cantabria, Spain

The Santa Maria de Cayon wastewater treatment plant is located in Saron, within the municipality of Santa Maria de Cayon in Cantabria, Spain. This facility serves a small population of 614 residents, reflecting its role in a rural or semi-urban community. The plant is situated inland, more than 10 km from the coast, and operates under Spain's implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC). The plant provides secondary treatment, which is the standard required by the EU directive for agglomerations of this size. With a designed capacity of 3,000 m³/day and an actual discharge volume of 111.29 m³/day, the plant operates well below its capacity, indicating potential for future growth or seasonal variations. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent is discharged into a local water body, likely a stream or river within the Cantabrian watershed. This region is characterized by a humid oceanic climate and diverse aquatic ecosystems. The plant's operation helps protect downstream water quality, supporting the ecological health of rivers that eventually drain into the Bay of Biscay.

The plant discharges into a local watercourse within the Cantabrian basin, which ultimately flows into the Bay of Biscay. This coastal area supports diverse marine life and is an important ecological zone. The secondary treatment reduces organic pollutants and nutrients, helping to prevent eutrophication and maintain water quality in downstream rivers and the coastal environment.