Mexico to start up LatAm's largest wastewater treatment plant

Thursday, March 19, 2015

ICA's Atotonilco water plant in the Mexican state of Hidalgo, the largest wastewater treatment project in Latin America and one of the biggest of its kind in the world, is set to come on stream this year.

The design, construction and operation of the plant is being carried out by a consortium made up of IDEAL, Acciona Agua, Atlatec and ICA at a cost of 10.1bn pesos (US$815mn), or more than US$100mn over the original budget.

BNamericas talked with Ricardo Morayta Martínez, director of the Atotonilco project.

BNamericas: How much water will this plant treat?

Morayta: The Atotonilco plant will treat 42m3/s, which is composed of 28m3/s for biological treatment and 14m3/s for biochemical treatment. The plant will treat 60% of the wastewater from the metropolitan area of Mexico City.

BNamericas: When will the plant be opened?

Morayta: Tests for the chemical part are estimated to start in April or May, and it will begin operations on December 23.

BNamericas: What were the main challenges during construction?

Morayta: Because of the topography it was necessary to stabilize a lot of slopes, some as high as 100m. It was also necessary to build a viaduct to connect the platforms and build an access road to link the plant to the filling area to avoid affecting the roads.

There were two special challenges that I think were the most significant during construction – construction of the drains and the digesters.

BNamericas: What will be the most significant benefits?

Morayta: Improving the quality of life and health for more than 700,000 people in the region, and providing quality water for irrigation areas.

With the treated water it will be possible to plant vegetables and recharge the aquifer with the highest quality water to explore fish farming and ecotourism opportunities.

The Tula aquifer will be a new source of drinking water. More than 40,000 people were hired during construction and about 200 will be hired over the next 20 years of operations. When the plant starts operations it will reduce carbon dioxide emissions by 45,000t.

BNamericas: Can this plant treat water that has been used in fracking to extract shale gas?

Morayta: Yes, it can; the plant can treat all water.

BNamericas: How can you bring water that was used for fracking to the plant?

Morayta: There are plans such as the Monterrey VI aqueduct, which we could use to bring water to the Atotonilco plant.

BNamericas: Could an aqueduct be built near Hidalgo state?

Morayta: There are plans.

BNamericas: How do you see the new water bill?

Morayta: In theory it doesn't affect us. For me, everything that's a benefit to health and water is good.

BNamericas: In what ways do you think this plant will adapt to the new water law?

Morayta: This plant considers all of that. From now on, Mexico's national water authority Conagua will not allow us to move a finger without being regulated.

BNamericas: How much energy can the plant generate?

Morayta: It will generate 32-33 MW, which will be used for self-consumption. Also we'll have power from Mexican state electricity company CFE.

BNamericas: What percentage of power will be self-generated?

Morayta: 60% of electricity, at its peak.

BNamericas: So, will the company buy the other 40% from CFE?

Morayta: Yes, but usually the plant will be self-sufficient.

BNamericas: What materials were used to build the plant?

Morayta: We used 380,000m3 of concrete, 44,000t of reinforced steel, 1Mm2 of geomembrane, 72km of pipes and 2Mt of wire were installed.

BNamericas: How long does a plant like this operate for?

Morayta: For over 20 years, but in theory this plant is guaranteed for around 100 years.

About the company

Mexican construction giant ICA is the largest EPC company and provider of construction services in the country.