Atotonilco, the largest wastewater treatment plant (WWTP) in the world built in a single phase

Mexico City faced a significant challenge in managing its wastewater, with only 36% of city and industry wastewater being treated. This situation has led to using contaminated water for agriculture and insufficient access to treated water for many inhabitants. In response to this challenge, the Mexican government initiated the Water Sustainability Program for the Mexico Valley Basin, intending to have 100% of city and industry wastewater treated by 2025.

The project will improve the living conditions of approximately 300,000 inhabitants in the region and forms a crucial part of the Sustainable Water Programme for the Mexico Valley, aimed to have 100% of city and industry wastewater treated by 2025.

This project was a vital component of the Water Sustainability Program for the Mexico Valley Basin, aimed at improving the sanitary conditions of the population and facilitating the technification of irrigation systems and crop production while allowing the use of treated water in agriculture.

Ayesa supervised the construction and commissioning of the Atotonilco water treatment plant, one of the largest wastewater treatment capacities in the world, with an average capacity of 35 m3/s that can reach a maximum of 50 m3/s, ten times more capacity than the largest Spanish water treatment plants. Our role in this project was to provide a state-of-the-art biological treatment system that can treat up to 1.99 million m3 of wastewater daily.

The plant features 24 tanks for biological treatment and 24 tanks for water clarification, and sludge extracted from the treatment process undergoes anaerobic digestion to produce biogas, which is then used to generate electricity through cogeneration engines. The plant uses biological treatment to treat around 1.99 million metres cubed daily. It has a primary treatment capacity of one million metres cubed per day for use in wet weather conditions, which is expandable to 2.5 million metres cubed. The plant’s total design capacity is around 4.5 million metres cubed daily. It can treat wastewater from a population equivalent to 12,600,000 of Mexico City’s inhabitants.

The Atotonilco wastewater treatment plant provides a range of benefits, including the reuse of treated water for irrigation, production of biofuels, increased treatment capacity, contribution to the Sustainable Water Programme, improved living conditions for inhabitants, job creation, greenhouse gas reduction, and extensive treatment capacity capable of treating wastewater from a population equivalent to 12,600,000 of Mexico City’s inhabitants.

These benefits improve the environmental conditions and raise the overall water treatment rate of the country, leading to improved health outcomes and a better quality of life for individuals in the region.