El Paso Water to Build First-of-Its-Kind Direct Potable Reuse Plant

With the world watching, El Paso, Texas, continues its work on an innovative direct potable reuse plant that could serve as a blueprint for other cities looking to diversify water portfolios

El Paso Water to Build First-of-Its-Kind Direct Potable Reuse Plant

An innovative four-step process that included membrane technology, reverse osmosis, ultraviolet disinfection with advanced oxidation, and granular activated carbon filtration comprised a DPR pilot project in the city of El Paso. (Photo Courtesy of EPWater)

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Drought has always been a challenge for the desert community of El Paso, Texas. With an average total rainfall of about 9 inches a year, they’ve learned to get creative when it comes to their drinking water supply.

For a long time, El Paso’s primary sources of potable water have been groundwater and river water. However, as the Rio Grande — its main water source — sees less snowmelt coming from northern New Mexico and southern Colorado, El Paso Water (EPWater) had to get even more creative. That's why its adding a first-of-its-kind direct potable reuse (DPR) system to the mix.

While climate does affect El Paso’s water resources, the population is growing, and that places an additional burden on EPWater. But EPWater is prepared for just about any situation. In fact, the utility started implementing a 50-year water plan in 1991, almost 30 years ago.

Christina Montoya-Halter, communications and marketing manager for EPWater, says that it is important to understand that this new move is not motivated by desperation. “It’s always been a goal for us to be diversified in terms of our water resources," she says.

So, for EPWater, using treated wastewater as a potable water source isn't much of a stretch. Apparently, it isn’t even that odd of a concept for residents. 

“We have a culture of conservation in El Paso,” says Montoya-Halter, who is a lifelong resident herself and remembers EPWater’s mascot Willie the Water Drop coming to her middle school to teach water conservation. “We didn’t just spring this idea on residents.”

A popular proposal

EPWater started talking to customers about the DPR project as early as 2014. First, it completed a phone survey with residents asking them if they would approve of EPWater putting highly treated wastewater directly back into the system. At that time, 84% of residents strongly approved of the project, and that was before EPWater did any specific outreach. 

From there, they began to educate their customers, and a few years later, they completed a similar survey with the result of about 90% of residents in favor of the project. 

When Montoya-Halter talks to other water departments, she says they are surprised by the overwhelming support of residents. She credits that support to the trust EPWater gained through ongoing education efforts it has implemented since 1985 when it first introduced indirect potable reuse and the conservation program. 

“People were accepting of it then, and they’re accepting of it now,” says Montoya-Halter. “(Earlier implementation of indirect reuse) also helped build a foundation for understanding about this initiative. So, people feel what we’re proposing to do is not that different.”

An innovative, educational pilot project

Perhaps it’s not that different in concept, but it’s very different in science. 

When you’re building a plant like this, the first in North America, it is not something you decide to develop overnight and then get to work. One of the first steps El Paso took was conducting a feasibility assessment partially funded by a grant from the U.S. Bureau of Reclamation. The next step was to construct and operate a self-funded pilot facility for nine months to assess the four core treatment processes. They engaged the ARCADIS engineering firm to drive the project and put the technology in place to obtain approval. 

ARCADIS came up with an innovative four-step process that included membrane technology, reverse osmosis, ultraviolet disinfection with advanced oxidation, and granular activated carbon filtration. Individually, these were all technologies that El Paso was using in several different plants. However, the innovation was in their combination.

While the engineering firm was running the project, EPWater staff continually observed and learned how everything worked. Moving forward, EPWater is considering getting some team members dual-licensed in wastewater and water to operate the new plant. 

Here's a rendering of the exterior of the plant created by the design team. (Graphic Courtesy of EPWater)
Here's a rendering of the exterior of the plant created by the design team. (Graphic Courtesy of EPWater)

Once the Texas Commission on Environmental Quality (TCEQ) approved the pilot results, EPWater had the green light to advance to the next stage — the design of the new Advanced Water Purification Facility (AWPF). EPWater received a grant from the U.S. Bureau of Reclamation in the amount of $3.5 million to put towards the design of the new facility. That grant covers 25% of the design and pilot testing phase, and EPWater will match the remaining 75%

Montoya-Halter says starting that relationship with funders at the design phase is important. Once funders have invested in the design, they have an interest in the success of the long-term project, which is bringing the plant online.

Sanaan Villalobos, PE, client services manager and vice-president of Carollo Engineers — the engineering firm contracted to do the design of the new plant — says a significant benefit of the pilot was being able to work closely with TCEQ navigating regulatory hurdles before moving on to the full-scale design. Villalobos says they could go into the design knowing they have a collaborative working relationship in place with TCEQ that was developed during the early stages of the project.

The world is watching

Because this is the first treatment plant of its kind in North America and only the second in the world, EPWater realizes it will likely serve as a showcase facility for their community and interested parties around the globe.

Therefore, the AWPF is being designed with education in mind. Visitors will gather in the lobby and then move into an auditorium where the treatment process will be explained. From there, they will walk down a long hallway and view the entire process through large windows. Monitors all along the path will broadcast each step of the process as the viewer observes it. However, the most exciting part is at the end, where they can get a taste of the final product.

Windows in the plant will allow for observational tours that explain the various processes in detail. (Graphic courtesy of EPWater)
Windows in the plant will allow for observational tours that explain the various processes in detail. (Graphic courtesy of EPWater)

Visitors will also be able to walk through the main treatment process area as well. Because of this public viewing, and with operators’ health and safety paramount, Villalobos says one goal of the design was to reduce the amount of noise that is generally produced by a treatment process area of this kind. Many of the large noise generating pumps were therefore placed outside rather than in the building treatment area.

Also, because this is a first-of-its-kind operation, Carollo enlisted the help of virtual reality (VR). Instead of just showing EPWater renderings or 3D drawings of the plant, operators can put on a VR headset and actually walk through the simulated plant just like they would if it were built and operational. VR allows the operators to identify issues that would never have been uncovered otherwise, such as tight, cramped quarters when performing maintenance or clearance issues. Villalobos says it also gives the operators a sense of ownership of the final design.

Both Villalobos and Montoya-Halter say when utilities are undertaking a similar project, giving yourself enough time is paramount. Time to communicate with the public and get them on board, time to go through the pilot phase and obtain regulatory approvals, time to provide your employees the skills they will need, and time to design a state-of-the-art plant. 

In EPWater’s case, the project started in 2012 when it first began exploring the AWPF as part of a feasibility assessment. The plan is for the actual plant to go online in a few years. Today, the design phase is about 30% complete. 

Of course, the process might move a bit faster for whoever decides to build the next DPR plant in North America.



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