La Colorada Wastewater Treatment Plant, Sonora, Mexico

La Colorada is a wastewater treatment plant located in the town of La Colorada, Sonora, Mexico. It serves a small population of approximately 300 residents, reflecting its role in a rural or semi-rural community. The plant is situated inland, more than 10 km from the coast, and its operations are part of the local municipal infrastructure. The plant provides secondary treatment, which is a standard biological process that removes organic matter and suspended solids. With a designed capacity of 82.08 cubic meters per day and a discharge volume of 53.57 cubic meters per day, it operates below its capacity. In Mexico, wastewater treatment plants are regulated under the National Water Law (Ley de Aguas Nacionales) and NOM-001-SEMARNAT-1996, which sets discharge limits for pollutants into national waters. The treated effluent is discharged into a local water body, likely an arroyo or small river that drains into the Gulf of California via the Sonora River basin. This inland discharge supports the local hydrological cycle and helps maintain water quality in downstream ecosystems, which are important for biodiversity and agricultural use in the arid Sonoran region.

The plant discharges into a local watercourse that is part of the Sonora River basin, which flows southward into the Gulf of California. The region is characterized by arid to semi-arid conditions, making water resources scarce and ecologically sensitive. The treated effluent contributes to base flow in intermittent streams, supporting riparian habitats and wildlife. Downstream, the Sonora River estuary provides critical nursery grounds for fish and migratory birds, though the plant's small scale limits its regional impact.