San Andres Huayapam Wastewater Treatment Plant, Oaxaca, Mexico

The San Andres Huayapam wastewater treatment plant is located in the municipality of San Andrés Huayapam, Oaxaca, Mexico. It serves a population of 3,012 residents, providing secondary treatment for the community's wastewater. The plant has a designed capacity of 285.12 cubic meters per day and operates at full capacity. As a secondary treatment facility, it meets the standard requirements for municipal wastewater treatment in Mexico under NOM-001-SEMARNAT-1996, which sets permissible limits for pollutants in treated wastewater. Plants serving populations under 10,000 are typically classified as small-scale systems, and secondary treatment is appropriate for this size to protect public health and the environment. The treated effluent is discharged into local water bodies, contributing to the protection of the surrounding watershed. The plant is located inland, more than 50 km from the coast, reducing direct marine impact. Its operation helps maintain water quality in the region's rivers and streams, supporting local ecosystems and downstream water uses.

The plant discharges into the local watershed within the state of Oaxaca, which drains into the Pacific Ocean via the Atoyac River and other coastal basins. The region's aquatic ecosystems support diverse species, including fish and amphibians, and the plant's secondary treatment helps reduce nutrient and pathogen loads, protecting downstream water quality and ecological health.