Sauz de Abajo Wastewater Treatment Plant | Durango, Mexico

Sauz de Abajo wastewater treatment plant is located in the small community of Sauz de Abajo, within the municipality of San Juan del Río, Durango, Mexico. The plant serves a population of 456, classifying it as a small-scale facility under Mexican wastewater regulations. The plant provides secondary treatment, which is the standard level required by Mexican norm NOM-001-SEMARNAT-1996 for municipal wastewater discharges into national waters. With a design capacity of 60.48 m³/day and an actual discharge volume of 43.20 m³/day, the plant operates at approximately 71% capacity, indicating adequate headroom for current demand. The treated effluent is discharged into local watercourses that ultimately drain into the Nazas River basin, part of the endorheic Bolsón de Mapimí region. This arid watershed supports limited aquatic life and is ecologically sensitive to nutrient loading, making the plant's secondary treatment important for protecting local water quality.

The plant discharges into the Nazas River basin, an endorheic system in the Bolsón de Mapimí region of northern Mexico. This arid watershed has limited surface water and supports a fragile ecosystem adapted to seasonal flows. Downstream, the water contributes to the Laguna de Mayrán, a shallow lake that serves as critical habitat for migratory birds and endemic species. Secondary treatment helps reduce organic load and nutrients, mitigating eutrophication risks in this sensitive environment.