Engineers Help City Save Water
NADIA M. WHITEHEAD | January 23, 2015 | UNIVERSITY COMMUNICATIONS
From left: Postdoctoral researcher Guillermo Delgado, Ph.D., an EPWU employee and Professor of Civil Engineering Anthony Tarquin, Ph.D., stand by Tarquin's novel desalination system known as the Concentrate Enhanced Recovery Reverse Osmosis (CERRO) process. Photo by Ivan Pierre Aguirre / UTEP News Service
Guillermo Delgado, Ph.D., busily tinkers with a flashing computer monitor. Numbers flicker and change on the screen, but he draws my attention to one that reads 74.1. "See, this tells us that we're running at about 74 percent efficiency," he said.
We're standing in a small warehouse that sits adjacent to Interstate 10. Behind the monitor stand a slew of large, white pipes, but one beige one stands out from the rest. It runs parallel to the floor for several yards until it turns and suddenly dives some 300 to 400 feet below ground.
This pipe is connected to an aquifer, an underground reservoir of water, said Delgado who works as a postdoctoral researcher at The University of Texas at El Paso. In order to make use of the subterranean resource, the city must pump the water to the surface. But the water doesn't come up from the ground clean; it is heavily concentrated with salt. Before it can be used by anyone, it must be desalinated.
That's where the 74 percent comes into play. A desalination system on site actively removes the salt, purifying about three-quarters of the water that is pumped up. But because current desalination technology is limited, the remaining 26 percent of the water pumped from the well is left concentrated with salt. Deemed unusable, it is dumped in the sewer as waste.
Concerned about dwindling water in arid regions, Delgado and Professor of Civil Engineering Anthony Tarquin, Ph.D., want to reduce the percentage of water that is being discarded by boosting the efficiency of desalination systems.
"We want to recover the water that is normally thrown away," said Tarquin, who has studied water conservation for the last 45 years. "Some of these wells discard 80 gallons a minute; that amounts to a lot of water discarded in a single day."
To conserve water, Tarquin and Delgado have designed a novel treatment system known as the Concentrate Enhanced Recovery Reverse Osmosis (CERRO) process. The patent-pending system can be applied to the leftover saltwater concentrate to recover further water.
Interested in taking advantage of the system, El Paso Water Utilities (EPWU) and the Bureau of Reclamation recently provided the research team with funds to install the system at three El Paso well sites.
"Once we are done, we're hoping that instead of dumping about 25 percent of the water into the sewer, only six percent will be disposed," said Delgado, who received his Ph.D. in civil engineering from UTEP.
The installation would save the city from discarding about 49 million gallons of water a year — enough to supply an additional 268 El Paso homes with their annual water needs — and lead to EPWU purchasing less water from El Paso County Water Improvement District #1, resulting in a savings of at least $42,000 a year.
CERRO will be installed at the three wells during the summer of 2015. If the systems are as successful as the researchers predict, they will be considered for installation at all 11 El Paso well sites and the Kay Bailey Hutchison Desalination Plant.
Installation at the local plant, which is Tarquin's ultimate goal, could provide the city with more than 977 million gallons of water a year.
Fernie Rico, EPWU's chief operations manager and a UTEP alumnus, said CERRO is being installed because "sustainability is paramount" in the desert Southwest. He added that by working together, EPWU and UTEP have the opportunity to create a cutting-edge water utility service for the city.
"El Paso Water Utilities must continue to plan ahead and have a water supply portfolio that is ready for emergencies, droughts and future growth," Rico said.
Delgado couldn't agree more.
"We're reaching a point here in El Paso where every drop counts," he said. "We need to become more efficient with our water and this project is a step in the right direction."