San Rafael 3 Wastewater Treatment Plant, San Rafael, Sonora, Mexico

San Rafael 3 is a municipal wastewater treatment facility located in San Rafael, within the municipality of Ures, Sonora, Mexico. The plant serves a small population of 383 residents, reflecting its role in a rural or peri-urban community. As a secondary treatment plant, it provides biological treatment to reduce organic pollutants and suspended solids before discharge. The plant operates under Mexico's national water regulations, which require wastewater treatment for all urban agglomerations. With a designed capacity of 34.56 cubic meters per day and a current discharge volume of 36.29 cubic meters per day, the facility is operating near its design capacity. Secondary treatment is the standard for communities of this size in Mexico, ensuring compliance with federal discharge standards. The treated effluent is discharged into local watercourses that ultimately drain into the Gulf of California via the Sonora River basin. The plant's inland location, over 50 km from the coast, reduces direct marine impact but contributes to the health of the region's freshwater ecosystems. Proper treatment helps protect downstream water quality and supports agricultural and ecological uses in the arid Sonoran environment.

The plant discharges into the Sonora River basin, which flows southward through the state of Sonora and empties into the Gulf of California. This arid region relies on limited surface water for irrigation and domestic use, making wastewater treatment critical for maintaining water quality. The receiving waters support diverse aquatic life and are part of a migratory corridor for birds and fish. Effective secondary treatment reduces nutrient loading and prevents eutrophication in downstream reservoirs and coastal zones.