In Mexico, fears a new plant will kill wastewater farming

For more than 100 years, most of what gets flushed down Mexico City's toilets has resurfaced two hours to the north in the rivers and reservoirs of the rural Mezquital Valley. A massive new water treatment plant is about to change this.

But rather than welcoming the prospect of cleaner water, angry farmers are demanding the government honor an 1895 presidential decree granting them the right to the capital's untreated sewage, which they see as fertilizer-rich, if foul, irrigation water.


In this April 1, 2017 photo, day laborers harvest broccoli grown with wastewater, near Mixquiahuala, Hidalgo state, Mexico. Farmers in the Mezquital Valley use untreated sewage from Mexico City to water and fertilizer their crops. "Our life comes from these waters. It is the sustenance," says farmer Don Justino Lopez of Tepatepec. (AP Photo/Rebecca Blackwell)


It's a standoff that pits public health concerns — not just for valley residents but for the Mexicans elsewhere who eat the crops — against fears that family farms will go under if they lose access to the raw sewage after the $530 million Atotonilco plant in Hidalgo state, billed as the largest of its kind in Latin America, goes online.

"My grandparents went with a pickaxe and a shovel opening the (irrigation) canals," said Teresa Alvarez, a 69-year-old grandmother who farms alfalfa, corn and wheat in the town of Tepatepec. "So it's not fair that all of a sudden they are taking away the waters, and we are going to fight."

The capital's waste was hardly seen as a boon when it first began arriving in the poor, semi-arid valley traditionally inhabited by the indigenous Otomi people. But over the decades, the "aguas negras," or "black waters," transformed the region into one of Mexico's most productive breadbaskets. Today, a vast network of low-tech, gravity-based canals irrigates more than 90,000 hectares (220,000 acres).

According to Fernando Sanchez, a 37-year-old opponent of the plant, corn fields here yield an average of 15 tons per hectare (6 tons per acre) and some produce as much as 18 tons (7.3 tons). Once they switch to treated water, he predicts that could fall by nearly half.


In this March 31, 2017 photo, Fernando Sanchez, jumps over a wastewater canal after irrigating an alfalfa field on the banks of the Endho reservoir north of Tula, Hidalgo state, Mexico. "My grandparents went with a pickaxe and a shovel opening the canals," said Teresa Alvarez, a 69-year-old grandmother who farms alfalfa, corn and wheat in the town of Tepatepec. "So it's not fair that all of a sudden they are taking away the waters, and we are going to fight." (AP Photo/Rebecca Blackwell)


Costs are also likely to rise as farmers switch to fertilizers and agrochemicals, which entail their own environmental risks, to make up for the loss of the sewage. Without government support, they say agriculture in the region could become unsustainable and spur migration to the United States and elsewhere in Mexico.

Farmers have been meeting with elected officials and the National Water Commission, known by its Spanish initials Conagua, to present their concerns. But suspicions run deep, especially since water has long been a scarce resource in central Mexico.

So far officials have been willing to listen, Sanchez said, but "what there is not, is an openness to find a solution for us."

Conagua declined multiple requests for comment. In brochures promoting the plant, which is in its testing phase and expected to come online later this year, the commission called the use of untreated sewage for farming "a public health problem."

It argued the plant will preserve many of the nutrients in the water, improve conditions for the valley's 700,000 residents, gradually reduce pollution in the region's waterways and allow the cultivation of currently banned crops.

"Hopefully we will see fewer diseases and there could be less sickness among humans," said Silvino Garcia, 62, who grows barley alongside the Endho reservoir in the valley. But the farmer fears the plant will lower farm output, adding "there are pros and cons."


In this March 17, 2017 photo, Silvino Garcia, 62, stands near a hay rake in his barley field after the cut stalks were turned to enable drying, on the banks of the Endho reservoir north of Tula in Hidalgo state, Mexico. Garcia is hoping the new wastewater treatment plant could eventually help clean the waste-water filled reservoir, which under the current plans will continue to receive untreated sewage. "There are pros and cons," he says. "Hopefully we will see fewer diseases and there could be less sickness among humans." But he fears the plant will lower farm output and increase costs. (AP Photo/Rebecca Blackwell)


The Mezquital Valley is a green-and-brown patchwork of small plots, most of them a single hectare (2.5 acres) or less, traced by narrow canals. From a distance the landscape looks bucolic; up close, in some parts, plastic bags and bottles choke the canals and foam billows several feet above the water. The sewage smell is faint in most places except near the Endho reservoir, where a fetid stench permeates homes and makes residents ashamed to invite outsiders to visit.

During wastewater flood irrigation, bacteria can contaminate low-lying crops and later invade consumers' digestive tracts if the produce is not disinfected or cooked. The World Health Organization says risks to consumers include increased rates of cholera, typhoid, diarrhea and roundworm infections.

Most of the crops grown in the valley are low risk to humans: Alfalfa, for example, is used for animal feed, and corn grows several feet above the water in protective husks.

But there are also plots of prohibited, ground-hugging produce such as cauliflower, broccoli and cilantro, all of which flow from the valley to Mexico City's Central de Abastos wholesale market and from there to street stalls, taco stands and dinner tables.


In this March 17, 2017 photo, a worker carries a shovel as he walks through an alfalfa field in early morning fog, on his way to manage the flood irrigation with wastewater of a field where corn will be planted, in Santa Ana Ahuehuepan, north of Tula, Hidalgo state, Mexico. For more than 100 years, most of what gets flushed down Mexico City's toilets has resurfaced two hours to the north in the rivers and reservoirs of rural Mezquital Valley. A massive new water treatment plant is about to change this. (AP Photo/Rebecca Blackwell)

In this April 1, 2017 photo, a day laborer hauls a load of broccoli to a truck during harvest, near Mixquiahuala, Hidalgo state, Mexico. Most of the crops grown in the valley are low risk to humans: alfalfa, for example, is used for animal feed; and corn grows several feet above the water in protective husks. But there are also plots of prohibited, ground-hugging produce such as cauliflower, broccoli and cilantro. (AP Photo/Rebecca Blackwell)


Efrain Gonzalez, who represents farmers from five towns around the city of Tula, has reservations about the plant but acknowledges there's something absurd about "waiting for 10,000 residents of the capital go to the bathroom so that I can fertilize my field."

Farmers who irrigate with wastewater also face health risks, including roundworm and other parasite infections, according to the WHO. Their children are more vulnerable to diarrheal disease and salmonella.

But most of the Mezquital farmers downplay the risks, claiming that generations of families have not suffered. In fact they often wash their hands in the brown water before settling down to eat lunch in the fields.

Manuel Ortega, an 89-year-old farmer, said he was raised on leafy greens, beans and zucchini grown here.

"It never gave me the runs," he added with a laugh.


In this March 31, 2017 photo, farmer Manuel Ortega, 89, lights a cigarette following a strategy meeting by farmers in Tepatepec, Hidalgo state, Mexico. Ortega, who still works in the fields and gets around town by bicycle, said he was raised on the leafy greens, beans and zucchini grown here. "It never gave me the runs," he added with a laugh. (AP Photo/Rebecca Blackwell)


Christina Siebe, a geologist at the National Autonomous University of Mexico who has spent decades researching farming in the Mezquital Valley, said while there are obvious problems with wastewater farming, it can reduce demand for scarce freshwater resources, keep organic waste from ending up in rivers and oceans, and recycle nitrogen, phosphorus and organic material.

She says it's not clear a treatment plant like Atotonilco is worth the cost.

"There are simpler and cheaper methods to reduce the risks. ... How you manage your land, what type of crops you produce and what hygiene practices you as a farmer use," Siebe said.

Another point of contention with locals is that Atotonilco lacks the capacity to treat all the capital's wastewater, with the part that currently fertilizes the fields getting cleaned and what's left over going into the valley's already-polluted waterways.

When the much-delayed plant is up and running, the portion of treated sewage produced by the metropolis of 20 million-plus people will rise to 57 percent, compared with 11 percent when construction began in 2010.

Mezquital farmers want to see no drop in the amount of water they receive or how much organic material it contains. If they don't get that, they vow to surround and occupy the plant.

"They are trampling on a historic right," said Juan de Dios, a farmer from Mixquiahuala.


In this April 1, 2017 photo, a farm worker irrigates black bean plants with wastewater near Tepatepec, Hidalgo state, Mexico. Rather than welcoming the prospect of cleaner water, farmers are demanding the government honor an 1895 presidential decree granting them the right to the capital's untreated sewage, which they see as fertilizer-rich, if foul, irrigation water.(AP Photo/Rebecca Blackwell)

In this March 17, 2017 photo, a worker dams off a canal to divert wastewater onto a field where corn will be planted, in Santa Ana Ahuehuepan, north of Tula, Hidalgo state, Mexico. It's a standoff that pits public health concerns, not just for valley residents but for the Mexicans elsewhere who eat the crops, against fears that family farms will go under if they lose access to the raw sewage. (AP Photo/Rebecca Blackwell)

In this March 17, 2017 photo, a river of untreated sewage flows past the $530 million wastewater treatment plant in Atotonilco de Tula, Hidalgo state, Mexico. After years of delays, the plant, billed as the largest of its kind in Latin America, is in its testing phase and expected to come online later this year. (AP Photo/Rebecca Blackwell)

In this March 17, 2017 photo, farmer Silvino Garcia, 62, shows a grain of the barley he grows as animal feed for the dairy industry, in his field alongside the Endho reservoir north of Tula, Hidalgo state, Mexico. The capital's waste was hardly seen as a boon when it first began arriving, but over the decades, the "aguas negras," or "black waters," transformed the region into one of Mexico's most productive breadbaskets. Farmers fear using treated water could cut their production in half, while creating new costs for fertilizer and agro-chemicals.(AP Photo/Rebecca Blackwell)

In this April 1, 2017 photo, a herder guides her sheep as they graze on the stubs of cut grain crops in the Otomi village of Dengantzha, near Tepatepec, Hidalgo state, Mexico. The semi-arid Mezquital valley, traditionally inhabited by the indigenous Otomi people, was named for the mesquite trees that grew there along with cactus before wastewater irrigation arrived. (AP Photo/Rebecca Blackwell)

In this March 17, 2017 photo, tires protect a field from a thick layer of mud ejected from an adjacent irrigation canal when high flow creates a 30-foot spray, near the Endho reservoir, Hidalgo state, Mexico. Today, a vast network of low-tech, gravity-based canals irrigates more than 90,000 hectares (220,000 acres) of the Mezquital Valley with wastewater. Communities in other Mexican states have followed Hidalgo's example, and begun using sewage for farm irrigation. (AP Photo/Rebecca Blackwell)

In this April 1, 2017 photo, a fairground ride sits parked between partially-constructed homes in the village of Tenhe, near Mixquiahuala, Hidalgo state, Mexico. Farmers say the "aguas negras" have allowed them to educate their children and raise their own standard of living. Without government support, they say agriculture in the region could become unsustainable after the new wastewater treatment plant opens and spur migration to the United States and elsewhere in Mexico. (AP Photo/Rebecca Blackwell)

In this March 31, 2017 photo, a thick layer of mud coats the earth around an irrigation canal where high flow in rainy season creates a 30-foot-high spray, near the Endho reservoir, Hidalgo state, Mexico. In brochures promoting the new wastewater treatment plant, the National Water Commission called the use of untreated sewage for farming "a public health problem" and a source of environmental pollution. (AP Photo/Rebecca Blackwell)

In this March 16, 2017 photo, day laborers, their boots caked in mud, arrange harvested cauliflower grown with wastewater atop a truck, near Mixquiahuala, Hidalgo state, Mexico. The National Water Commission argued the new wastewater treatment plant will preserve many of the nutrients in the water, improve conditions for the valley's 700,000 residents, gradually reduce pollution in the region's waterways and allow the cultivation of currently banned crops, such as cauliflower. (AP Photo/Rebecca Blackwell)

In this March 31, 2017 photo, the carcass of a lamb floats amidst garbage in an irrigation canal, in Santa Ana Ahuehuepan, north of Tula, Hidalgo state, Mexico, Friday. From a distance the valley's landscape looks bucolic; up close, in some places, plastic bags and bottles choke the canals and foam billows several feet above the water. (AP Photo/Rebecca Blackwell)

In this March 17, 2017 photo, foam from household detergents rests atop wastewater in an irrigation canal near the Endho reservoir in Tula, Hidalgo state, Mexico. Although the farmers are reluctant to lose the organic content in their black waters, they would support removing the contaminants which bother them more: heavy metals, industrial chemical pollution, detergents, and oils. The new wastewater treatment plant won't intentionally remove heavy metals or industrial chemical pollution, but many of the metals should remain in the sediments extracted inside the plant. (AP Photo/Rebecca Blackwell)

In this March 16, 2017 photo, workers place a net over the bed of a truck filled with cauliflower as they harvest a field grown with wastewater, near Mixquiahuala, Hidalgo state, Mexico. Efrain Gonzalez, who represents farmers from five towns around the city of Tula, has objections to the wastewater treatment plant but acknowledges there's something absurd about "waiting for 10,000 residents of the capital go to the bathroom so that I can fertilize my field." (AP Photo/Rebecca Blackwell)

In this Feb. 15, 2017 photo, members of the "Council of Users in Defense of the 'Aguas Negras'" talk with other farmers representing their communities as they prepare for a meeting with elected deputies at the Hidalgo State legislature in Pachuca, Mexico. Farmers have been meeting with elected officials and the National Water Commission to present their concerns. But suspicions run deep, since water has long been a scarce and contentious resource in central Mexico. (AP Photo/Rebecca Blackwell)

In this March 17, 2017 photo, level indicators mark the side of a conduit where sewage from Mexico City arrives, before being divided into two streams, one for farm irrigation and the other flowing into the Tula River and the Endho reservoir, in El Salto, Hidalgo state, Mexico. Another point of contention with locals is that the plant lacks the capacity to treat all the capital's wastewater, with only the part that currently fertilizes the fields slated for cleaning and what's left over going into the valley's already-polluted waterways. (AP Photo/Rebecca Blackwell)

In this April 1, 2017 photo, foam from detergents flows into a field of black beans as it is irrigated with wastewater near Tepatepec, Hidalgo state, Mexico. Farmers who irrigate with wastewater face health risks, including roundworm and other parasite infections, according to the World Heath Organization. But most of the Mezquital farmers downplay the risks, claiming that generations of families have not suffered. In fact they often wash their hands in the brown water before settling down to eat lunch in the fields. (AP Photo/Rebecca Blackwell)

In this March 17, 2017 photo, Margarito Sanchez closes the hood of his pickup after making a minor repair, in a farm field where his family grows ornamental lawn grass for sale, in Tepatepec, Hidalgo state, Mexico. Such water-intensive crops would have been unimaginable before Mexico City's sewage brought large quantities of water to the semi-arid valley. Farmers say the income from the "black waters" has helped them trade donkeys and yoked plows for pick-up trucks and tractors. (AP Photo/Rebecca Blackwell)

In this March 16, 2017 photo, refuse piles up behind a flow control gate in a principal wastewater irrigation canal near Mixquiahuala, Hidalgo state, Mexico. When the much-delayed plant is up and running, the portion of the metropolis' 20 million-plus people's sewage that gets treated will rise to 57 percent, compared with 11 percent when construction began in 2010. (AP Photo/Rebecca Blackwell)

In this April 1, 2017 photo, a sheep chases away a herding dog as she protects her newborn lamb, carried in a cloth bag astride a donkey, after the sheep gave birth as the flock grazed on stubs of cut crops in the Otomi village of Dengantzha, near Tepatepec, Hidalgo state, Mexico. Not all valley residents agree with the farmers. "The pollution does harm," said 41-year-old painter Benito Hernandez of Mixquiahuala. "The farmers don't want to see it." (AP Photo/Rebecca Blackwell)

In this March 16, 2017 photo, a boy accompanies his mother as she harvests zucchini flowers from a field irrigated with wastewater, near Mixquiahuala, Hidalgo state, Mexico. Geologist Christina Siebe who has spent decades researching farming in the Mezquital Valley says it's not clear a large-scale treatment plant like Atotonilco is worth the cost. "There are simpler and cheaper methods to reduce the risks. ... How you manage your land, what type of crops you produce and what hygiene practices you as a farmer use," Siebe said. (AP Photo/Rebecca Blackwell)

In this April 12, 2017 photo, zucchini flowers grown with wastewater near Mixquiahuala are displayed for sale at the Central de Abastos, the capital's main market, in Mexico City. The edible flowers are a popular ingredient in quesadillas. During wastewater flood irrigation, bacteria can contaminate low-lying crops and later invade consumers' digestive tracts if the produce is not disinfected or cooked. The World Health Organization says risks to consumers include increased rates of cholera, typhoid, diarrhea and roundworm infections. (AP Photo/Rebecca Blackwell)

In this April 1, 2017 photo, a farmer and his son look on as they flood irrigate a field with wastewater before planting corn, in Mixquiahuala, Hidalgo state, Mexico. Mezquital farmers want to see no drop in the amount of water they receive or how much organic material it contains. If they don't get that, they vow to surround and occupy the plant. "They are trampling on a historic right," said Juan de Dios, a farmer from Mixquiahuala. (AP Photo/Rebecca Blackwell)


Text from the AP news story, In Mexico, fears a new plant will kill wastewater farming, by Rebecca Blackwell.

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