Potrero Wastewater Treatment Plant, El Potrero, San Luis Potosí

Potrero is a wastewater treatment plant located in El Potrero, within the municipality of San Martín Chalchicuautla, San Luis Potosí, Mexico. The plant serves a population of approximately 2,738 people, classifying it as a small-scale facility in the region. It is situated inland, more than 10 km from the coast, but within 50 km of the Gulf of Mexico coastline. The plant operates with secondary treatment, which is the standard level required under Mexican regulations (NOM-001-SEMARNAT-1996) for municipal wastewater before discharge. The designed capacity and discharge volume are both reported as 259.20 units, indicating the plant is operating at full capacity. As a small agglomeration, secondary treatment is appropriate for protecting local water quality. The treated effluent is discharged into local water bodies that ultimately drain toward the Gulf of Mexico. The plant plays a key role in reducing organic and nutrient pollution in the region, supporting downstream aquatic ecosystems and preventing eutrophication in coastal waters. Its operation contributes to the overall sanitation infrastructure of San Luis Potosí.

The plant discharges into local streams that flow into the Pánuco River basin, which drains into the Gulf of Mexico. This watershed supports diverse aquatic life and is important for regional fisheries. Secondary treatment helps control organic loads and nutrients, reducing the risk of algal blooms and oxygen depletion in downstream waters.