Santiago Huajolotitlán Wastewater Treatment Plant, Oaxaca, Mexico

The Santiago Huajolotitlán wastewater treatment plant is located in the town of Santiago Huajolotitlán, in the state of Oaxaca, Mexico. It serves a population of approximately 2,738 residents, making it a small-scale municipal facility. The plant is situated inland, more than 10 km from the coast, and treats wastewater from the local community. The plant operates with secondary treatment, which is the standard biological treatment process for removing organic matter and suspended solids. It has a designed capacity of 259.20 m³/day and discharges a similar volume of treated wastewater. Under Mexican regulations (NOM-001-SEMARNAT-1996), secondary treatment is required for municipal wastewater to meet discharge standards for receiving water bodies. The treated effluent is discharged into a local watercourse that eventually drains into the Pacific Ocean via the Balsas River basin or other regional hydrology. The plant plays a key role in protecting local water quality and preventing untreated sewage from affecting downstream ecosystems and communities.

The plant discharges into a local stream that flows into the Balsas River basin, which ultimately reaches the Pacific Ocean. This watershed supports diverse aquatic life and provides water for agricultural and domestic use in the region. The secondary treatment helps reduce nutrient and pathogen loads, protecting downstream water quality and ecological health.