El Llano Wastewater Treatment Plant, San Juan Ixtayopan, Ciudad de México

El Llano is a wastewater treatment plant located in San Juan Ixtayopan, a community within the Tláhuac borough of Ciudad de México, Mexico. The plant serves an estimated population of 58,524 residents, placing it in the medium agglomeration category for Mexican wastewater infrastructure. As a plant in Mexico, El Llano is subject to the country's federal water laws, including the Ley de Aguas Nacionales and NOM-001-SEMARNAT-2021, which set discharge standards for pollutants. The plant's treated effluent likely discharges into local water bodies within the Valley of Mexico basin, which ultimately drains into the Pánuco River system and the Gulf of Mexico. The region's high altitude and semi-arid climate make water management critical for both human use and ecological health.

The plant is situated in the Valley of Mexico, an endorheic basin historically containing Lake Texcoco. Treated wastewater from El Llano likely flows into the drainage network that feeds the Pánuco River, which travels northeast to the Gulf of Mexico. This watershed supports diverse aquatic life and provides water for agriculture and urban use downstream. The region's shallow water table and clay soils make groundwater recharge and surface water quality particularly sensitive to pollution.