Larry Webb, head of Rio Rancho's water department, is leading efforts to treat sewage and return it to the city's aquifer for later reuse, which would be a New Mexico first. (John Fleck/Journal)
RIO RANCHO – Water is so precious in the dry sand hills of Rio Rancho that sewage is an asset.
Faced with a rising population and a constrained supply, the city could soon become the first community in New Mexico to do something increasingly common elsewhere across the arid West – clean up its sewage and inject the water back into the aquifer so it can be pumped up and used again.
In other states, especially water-short Arizona and Southern California, cleaning up sewage and reusing it in new and creative ways is becoming common. And in less obvious ways, by returning sewage effluent to New Mexico’s rivers, or using it to water our golf courses, for example, reuse has long been common in New Mexico.
But Rio Rancho’s experiment, about to get under way beneath a nondescript cinder-block building above the city’s Loma Colorado neighborhood, is a step toward what could be a New Mexico first.
Here, workers have drilled a 1,700-foot well into the aquifer beneath the city. For 30 days this year, the city’s water department will pump water down the well to recharge the aquifer beneath the city. For this pilot phase of the project, the water pumped underground will simply be drinking water, diverted from the city’s municipal system. But if the project goes well, Rio Rancho plans to turn to sewage from a nearby treatment plant. The sewage will be cleaned up to drinking water standards and injected back into the ground so that it can eventually be pumped up and used again.
Instead of a continually dropping aquifer in the area as a result of groundwater pumping, the hope is that the water table will rise, said Larry Webb, head of the city’s water department.
It is no surprise that Rio Rancho would be the pioneer among large New Mexico municipalities. As a new city that did not incorporate until 1981, it missed out on the 1960s water deals that brought imported San Juan-Chama water to Albuquerque and Santa Fe. Its only water source is the aquifer beneath the city.
“We’re totally dependent on groundwater,” explained city manager James Jimenez.
As it became clear that Rio Rancho’s rapid growth was outstripping that supply, the city adopted a wide-reaching plan to develop alternatives. One of those was finding ways to better use its treated sewage effluent, rather than simply returning it to the Rio Grande.
In so doing, Rio Rancho is part of a trend. As growing population and an expanding economy push U.S. water supplies to the limit, various forms of effluent reuse have become increasingly attractive, according to a report earlier this month by a team of water experts for the federally sponsored National Research Council.
Reuse becoming more common
“Reclaimed water provides a constant and reliable source of water, even during drought conditions,” the report concluded.
As populations grow and water becomes an even more scarce commodity, reuse is likely to become more common, said University of New Mexico professor Denise Fort, a member of the National Research Council study team. “Most water is going to be reused,” she said.
“We anticipate it will continue to grow,” said Jim Davis, director of the New Mexico Environment Department’s Resource Protection Division.
Rio Rancho is not alone in pursuing the technology. Across New Mexico, cleaning up sewage effluent sufficient to water parks and golf courses has been common for decades, said Robert George, who oversees water reuse permitting at the state Environment Department. He estimated that two-thirds of the state’s golf course are watered with treated effluent.
New Mexico’s water systems have also long engaged in what the National Research Council dubbed “de facto reuse,” discharging treated sewage effluent into rivers, where it becomes part of the water supply for whoever uses water downstream.
Thus Española’s discharge in the Rio Grande, for example, eventually flows down to Albuquerque, where it becomes part of the intake supply for Albuquerque’s drinking water system.
The National Research Council report calls things like golf course water and return flows into rivers “low hanging fruit,” most of which it says U.S. municipalities have picked. The difference in the Rio Rancho project, and other similar efforts now getting under way in New Mexico, is the shift toward ever more direct reuse.
♦ Cloudcroft in 2009 almost became the first New Mexico community to use effluent directly, with a project to heavily treat sewage before putting it back in a drinking water reservoir. Technical problems when the project came on-line forced it to shut down within months, before any of the water was introduced into the drinking water supply, but reuse could restart this year, said project chief Tom Stewart.
♦ The Albuquerque Bernalillo County Water Utility Authority recently did a study on the possibility of pumping treated effluent into Albuquerque’s aquifer.
♦ Santa Fe, which already uses effluent for outdoor irrigation, has launched a study of the possibility of using some of the water for other purposes, including aquifer recharge.
‘The yuck factor’
Cleanup technologies like the “membrane bioreactors” to be used in the Cloudcroft and Rio Rancho projects are capable of cleaning the sewage to drinking water standards, making it safe to drink, the National Research Council report concluded. University of New Mexico water engineering expert Bruce Thomson, who worked with Cloudcroft on that community’s project, believes the current technology can safely clean up the water, effectively eliminating the dangers in untreated sewage.
“I think the risk is very, very low,” Thomson said.
But the trick remains to get past what Thomson calls “the yuck factor.”
“People have been trained for generations to provide separation in both time and space between their wastes and their water supplies,” the National Research Council report concluded, “and therefore the public is concerned about the safety of using wastewater effluent for domestic purposes.”
El Paso, a pioneer in the field of effluent reuse, got over the yuck factor problem long ago, said Ed Archuleta, who heads that city’s water utility and was a co-author of the National Research Council Report. El Paso injects treated sewage into the aquifer, then pulls it up out of the ground in a well field a mile away. They figure it takes five or six years to make the trip from sewage plant to drinking water wells, Archuleta said.
Archuleta said the yuck factor has been “a nonissue” in El Paso, noting that what his utility does is no different from de facto reuse, when cities draw water from a river downstream from their neighbors’ sewage treatment plant.
“We’ve been practicing de facto reuse for decades,” Archuleta said. “There’s always somebody upstream.”
New Mexico and other arid regions where sewage is discharged into rivers have another problem with expanded reuse. Every gallon turned from the sewage outfall to a golf course or aquifer recharge is one less gallon put into the river for people living downstream.
“When they take the water out, all of a sudden there’s less water in the river,” Thomson explained.
In the case of Albuquerque and Rio Rancho, much of the water being added to the river amounts to a subsidy – water pumped from the aquifer, used in homes and then added to the river. In the long run, state water accounting rules require the cities to pay that water back, primarily by buying and retiring agricultural water. But both water agencies have decided that, for some of their water, putting it directly back into the aquifer makes more sense.
— This article appeared on page A1 of the Albuquerque Journal
Reprint story -- Email the reporter at jfleck@abqjournal.com. Call the reporter at 505-823-3916
