The Wastewater Treatment Plant “Atotonilco” treats around 35% of the total wastewater from the Mexico Valley, equivalent to 16.8 million people, under a BOT scheme that considers the design, construction, financing, operation and maintenance of the project for 25 years.

The main processes include: pretreatment, primary treatment, biological treatment, chemical enhanced primary treatment, disinfection, sludge treatment, anaerobic digestion, sludge dewatering, odor control and cogeneration with biogas for the production of electrical energy and heat recovery.