San Pedro El Saucito Wastewater Treatment Plant, Sonora, Mexico

San Pedro El Saucito wastewater treatment plant is located in the town of San Pedro el Saucito, within the municipality of Hermosillo, Sonora, Mexico. The plant serves a population of approximately 3,906 people, reflecting its role as a small-scale municipal facility in a semi-arid region of northwestern Mexico. The plant provides secondary treatment, which is the standard biological treatment process for removing organic matter and suspended solids. With a designed capacity of 1,296 cubic meters per day and an average discharge volume of 369.79 cubic meters per day, the plant operates well below its capacity. Under Mexican regulations (NOM-001-SEMARNAT-1996 and subsequent updates), secondary treatment is required for discharges into national waters, and the plant's performance is subject to monitoring by the Federal Attorney for Environmental Protection (PROFEPA). The treated effluent is discharged into local water bodies that ultimately drain into the Gulf of California, a biologically productive sea that supports fisheries and marine biodiversity. The plant's operations help protect downstream ecosystems, including coastal wetlands and estuaries, from untreated wastewater pollution.

The plant discharges into the Sonora River basin, which flows through the Sonoran Desert and eventually reaches the Gulf of California. This coastal region supports diverse marine life, including shrimp, fish, and migratory birds. The semi-arid climate means water resources are scarce, making wastewater treatment crucial for maintaining water quality in the river and protecting the downstream marine environment from nutrient pollution and pathogens.