This sector consists of two Water Treatment Plants designed to process wastewater into a reusable resource for irrigation of agricultural areas and other purposes appropriate to their characteristics.

Their design and construction considers the development, operation, preservation, maintenance of the facilities and distribution channels, and the mitigation of all environmental impacts.

Las Plantas de Tratamiento de Aguas Residuales (PTAR) Saltillo y Atotonilco, tienen una capacidad de tratamiento conjunta de 36.27 metros cúbicos por segundo.

Atotonilco WWTP

Wastewater generated in the Valley of Mexico have been misused for more than 100 years to irrigate crops in the Mezquital Valley of the State of Hidalgo, which resulted unhealthy.


On January 07, 2010, the consortium Aguas Tratadas del Valle de México (ATVM) formed by the companies Promotora del Desarrollo de América Latina (IDEAL), Acciona Agua, Atlatec, ICA, Desarrollo y Construcciones Urbanas (DYCUSA), and Green Gas Pioneer, entered into a 25-year service contract with CONAGUA for the design, construction, equipment, testing, commissioning, operation, conservation, maintenance, and replacement of equipment for the Atotonilco Wastewater Plant, located in the city of Atotonilco de Tula, Hidalgo. It also includes the treatment of solid waste, temporary storage, the final disposal, and the cogeneration of electric power and heat for internal consumption.

On December 01, 2017, the WWTP started its commercial operation, being the largest in Latin America and among the world’s largest.


The main objectives of the WWTP are: reusing treated wastewater in agriculture, sanitation of watercourses, generating energy from the digestion of muds with biogas, and avoiding the burning of the environment and the emission of pollutants.

The treated influent is a mixture of rainwater and wastewater from municipal and industrial sources. Both of which come from the Metropolitan Zone of the Valley of Mexico. The current irrigation technique is only for corn and fodder crops. But with the operation of the Atotonilco WWTP, it is possible to change irrigation techniques and the crops. The function of the plant allows the adequate stabilization of the biosolids (mud treatment) to be used as a soil improver in agriculture. More than 800,000 inhabitants of the Valle del Mezquital benefit from the plant, and approximately half live directly in the irrigated areas.

Saltillo WWTP

Due to the contamination of the streams in the city of Saltillo, hydraulic infrastructure works were carried out for the treatment of the city’s wastewater, which included the sanitation of the streams through the construction of 4 important outfalls for the collection of sewage known as Cerritos, Satélite, del Pueblo and Principal, the construction and operation of the Wastewater Treatment Plants (WWTP) named “Principal” in the city of Ramos Arizpe and “Gran Bosque Urbano” in the city of Saltillo, and the promotion of the use of treated water through an independent network, which supplies this type of water from the “Gran Bosque” plant inside the same park, Aurora Park also called Paraíso ecological park, Paseo la Reforma, Campo Redondo de la U. A. de C., and Ateneo.

On November 16, 2004, Saltillo government and IDEAL Saltillo entered into a provision of services contract, in order to carry out the executive project, construction, electromechanical equipment, performance tests, operation, maintenance, and conservation of the Principal and Gran Bosque Urbano wastewater treatment plants, as well as the removal and final disposal of solid waste and mud generated therein for 20 years.


The project started operations on April 28, 2008. To date, these WWTPs have been operated and maintained efficiently in compliance with contractual and regulatory guidelines.

The purpose of the Saltillo WWTP is to provide wastewater with the required treatment so that it can be adequately discharged in accordance with water quality standards to benefit the agricultural infrastructure and agricultural workers with the use of treated wastewater, to improve the living conditions and health of the inhabitants of the city of Saltillo, and to optimize water use by reducing the consumption of potable water in activities that could use treated wastewater, such as irrigation of green areas.