ATVM partners with CONAGUA in Mexico

Access to potable water has long been an issue for Mexico, but the new Atotonilco Wastewater Treatment Plant is looking to fix that, writes Aldo Víctor Salmeron Cortés, Project Manager at ATVM


Access to natural resources can so often underpin the successes and failures of major economies, and while oil and gas remain the most sought after of all resources, there are others that are equally – if not more – important to spurring economic growth. The availability of clean water, for example, is perhaps the single most important facet of all, in particular among emerging markets where the absence of clean water can too often stymie economic progress.

It is estimated that the average family in the Valley of Mexico spends in excess of 4,000 pesos per year compensating for deficiencies in the region’s water supply

Nowhere can this better be seen than in Mexico, where the completion of a new wastewater treatment plant in the Hidalgo state looks set to not only improve sanitary conditions, but to better the country’s capacity for agricultural irrigation. The $792m public-private partnership will, on completion, equate to not only the largest of its kind in Mexico but also the fourth largest worldwide. Developed by the National Water Commission of Mexico (CONAGUA), the plant looks to accommodate the 20-million-strong metropolitan population of Mexico City who currently generate approximately 40 cubic metres of sewage per second. Shortfalls in the city’s current sewage system see a small proportion reused for municipal and industrial purposes and the vast majority left entirety untreated and unchecked for use in agricultural irrigation further afield.

Irrigated agriculture constitutes the vast majority of Mexico’s agricultural exports, so it is of vital importance that advances in the country’s ailing infrastructure be made in order to spur a greater measure of economic growth.

Wastewater problems
The current system represents a troubling state of affairs for inhabitants of the Tula Valley, as the untreated water is put to agricultural use in over 90,000 hectares of land; home to approximately 300,000 inhabitants who are each regularly subjected to environmental concerns.

The Atotonilco wastewater treatment plant looks to rectify this problem, at least in part, by hygienising 60 percent of Mexico City’s wastewater – a far cry from today’s eight percent. Located 40km north of the city, in Atotonilco town, Hidalgo, the project is proving an effective means of job creation as well as a solution to many of Mexico City’s immediate economic concerns.

The project was assigned by Mexico’s national water commission CONAGUA (which has a 2030 plan for water in Mexico) to Aguas Tratadas del Valle de Mexico (ATVM) in December 2009, a consortium composed of a great many industry entities. ATVM looks to collate the efforts of IDEAL, Atlatec, Acciona Agua, Infrastructure Operations Controller (CONOISA), Construction and Urban Development (DYCUSA) and Green Gas Pioneer Crossing Energy into the design, execution, installation and testing phases of the project over a 25-year period.

IDEAL controls the largest stake in the consortium at 40.8 percent, followed by Acciona Agua and Atalec who each own a 24.26 percent stake; CONOISA has 10.2 percent. The consortium partners will finance 20 percent with equity, 31 percent with credit from the National Bank of Public Works and Services (BANOBRAS), and the National Development Fund of Mexico (FONADIN) will contribute a further 49 percent.

The implementation period of the project is 300 months (25 years), which began in July 2010. In this period, 54 months are set aside for the construction, equipment and performance testing, and the remaining 246 months allocated to the operation, upkeep and maintenance of the completed plant. On completion, the plant will be capable of treating 3.6 million tonnes of water per day, raising the overall treatment rate of the country from 36 to 60 percent in one fell swoop.

Better water for all
The objectives of the wastewater plant are vast and far-reaching, and it has the potential to greatly improve the quality of life for those native to the region. So far the project has created 3,000 direct and 8,000 indirect jobs over its short three-year period of construction, and, when operational, will create better living conditions for over 700,000 inhabitants.

It is estimated that the average family in the Valley of Mexico spends in excess of 4,000 pesos per year compensating for deficiencies in the region’s water supply. Whether it be irregularities in supply or a general lack of availability, Mexico City’s inhabitants are subject to gross monthly costs for drainage and sanitation services. The World Bank claims that 91.6 percent of the region’s inhabitants have access to drinkable water, adding that demand for the resource far outstrips the Valley of Mexico’s supply. The organisation also draws attention to the region’s shortfalls as compared to similar locales, using Monterrey as an example, which has 6.5 times more water available per inhabitant than the Valley of Mexico.

The average capacity of the completed Atotonilco plant is estimated to reach as much as 42 cubic metres per second, with average dry season capacity being 23 cubic metres per second in wet conditions or as much as 35 cubic metres per second when using physical-chemical processes.

Put another way, the plant will have a 526 million gallons daily capacity year-round and a sustained flow of 960 million gallons daily during the rainy season. The sludge produced by the plant will be stabilised by means of anaerobic digestion, thus removing the need for dedicated onsite disposal.

The treatment process will also generate an estimated 60 percent of the energy required to power plant operations with biogas fuel. On top of the 32.4MW of electricity produced, the plant will be one of the world’s largest consumers of biogas, and could cut CO2 emissions by approximately one million tonnes each year.

According to ATVM, the primary objectives of the plant are to protect the health of farm workers and their families, prevent the spread of pollution in the region, restore the Endhó dam and organically rid it of any contaminants, facilitating advances in irrigation technology. Provided the finished plant meets each of its objectives, the Valley of Mexico population will be granted a far better standard of living, with its agricultural sector having a far better chance of growth. By improving upon the region’s overall service, coverage, and inefficiencies, Mexico can begin to move away from its long history of water-related hindrances.