Trinidad Zaachila Wastewater Treatment Plant, Villa de Zaachila, Oaxaca

Trinidad Zaachila is a municipal wastewater treatment plant located in Villa de Zaachila, Oaxaca, Mexico. The plant serves a population of approximately 1,825 residents, classifying it as a small-scale facility within the region's wastewater infrastructure. The plant provides secondary treatment, which is the standard biological treatment process for removing organic matter and suspended solids. With a designed capacity of 285.12 m³/day and a current discharge volume of 172.80 m³/day, the plant operates below its full capacity. Under Mexican regulations (NOM-001-SEMARNAT-1996), secondary treatment is required for discharges into national waters, ensuring compliance with federal water quality standards. The treated effluent is discharged into the local watershed, which ultimately drains into the Pacific Ocean via the Atoyac River basin. The plant plays a crucial role in protecting downstream water quality and supporting the ecological health of the region's aquatic systems.

The plant discharges into the Atoyac River basin, which flows through the Valles Centrales region of Oaxaca before reaching the Pacific Ocean. This watershed supports diverse aquatic life and is important for local agriculture and communities. The secondary treatment provided by the plant helps reduce nutrient and organic pollution, mitigating eutrophication risks in downstream water bodies.