San Pedro Tapanatepec Wastewater Treatment Plant, Oaxaca, Mexico

The San Pedro Tapanatepec wastewater treatment plant is located in the municipality of San Pedro Tapanatepec, Oaxaca, Mexico. It serves a population of approximately 3,012 people, classifying it as a small-scale municipal facility. The plant is situated near the Pacific coast, within 10 km of the shoreline, which influences its discharge considerations. The plant provides secondary treatment, a standard level for municipal wastewater in Mexico under NOM-001-SEMARNAT-1996, which sets pollutant limits for discharges into national waters. The facility has a designed capacity of 285.12 cubic meters per day and reports a discharge volume of 285.12 cubic meters per day, indicating full capacity utilization. As a coastal plant, it must comply with stringent effluent standards to protect marine environments. The treated effluent likely discharges into a local watercourse that drains into the Pacific Ocean, potentially affecting coastal ecosystems such as estuaries and mangroves. The region's tropical climate and proximity to the Gulf of Tehuantepec make the receiving waters ecologically sensitive, supporting diverse aquatic life and important fisheries.

The plant discharges into a local drainage system that ultimately reaches the Pacific Ocean near the Gulf of Tehuantepec. This coastal area supports mangrove forests and estuarine habitats that are critical for fish nurseries and migratory birds. The secondary treatment helps reduce organic load and pathogens, but nutrient removal may be limited, posing risks of eutrophication in the sensitive coastal zone.