Coyoacán Wastewater Treatment Plant, Ciudad de México, Mexico

The Coyoacán wastewater treatment plant is located in the Coyoacán borough of Ciudad de México, Mexico. It serves an estimated population of 115,807 residents, making it a medium-to-large agglomeration within the densely populated Mexico City metropolitan area. The plant is part of the city's extensive wastewater infrastructure managed by local authorities. As a plant serving over 100,000 people, it falls under Mexico's national water quality standards (NOM-001-SEMARNAT-1996 and subsequent updates), which mandate treatment levels based on receiving water body sensitivity. Plants of this scale typically employ secondary or advanced treatment to meet regulatory requirements for discharge into the region's water systems. The treated effluent from the Coyoacán plant ultimately drains into the Valley of Mexico basin, which historically flowed into the Lake Texcoco system. Today, much of the wastewater from the metropolitan area is conveyed through the Grand Canal and deep drainage tunnels to the Tula River basin, eventually reaching the Gulf of Mexico. The plant plays a critical role in protecting local water bodies and public health in one of the world's largest urban areas.

The Coyoacán plant discharges into the Valley of Mexico watershed, a closed basin that originally contained Lake Texcoco. Due to urban development, the basin's hydrology has been heavily modified, with wastewater now routed through the Tula River system to the Gulf of Mexico. The plant's operations help reduce pollution loads in this sensitive urban environment, supporting downstream aquatic ecosystems and water quality in the Tula River and Pánuco River basin.