The city of El Paso, Texas, may soon become the first large city in the US to use treated sewage water for its drinking water needs. The amount of snowmelt feeding the Rio Grande has dropped 25% since 1958 and is “critically low,” J. Phillip King, an adviser to the Elephant Butte Irrigation District, told CNN. The use of treated wastewater will add a significant source of water to the city’s supplies.
The Elephant Butte Reservoir illustrates the increasingly dire situation: currently, it sits between 3% and 4% of its full capacity. King said the Colorado River is facing a similar fate in a few years.
The Rio Grande generally provides as much as half of the city’s water, but as the region becomes increasingly vulnerable to drought, the city is seeking new sources. While El Paso’s desalination plant, which treats brackish water from the depths of the Hueco Bolton aquifer, can produce up to 27 million gallons of water daily and may provide up to 9% of the city’s water next year, existing sources may not be enough to close the gap between supply and demand.
El Paso’s Advanced Purification Facility
El Paso already uses treated wastewater for irrigation and industrial purposes; it is now building an advanced purification system that will treat sewage water and turn it directly into drinking water.
El Paso Water describes the treatment process this way: “Water passes through several phases of membrane filtration and disinfection using advanced water purification. This multiple-stage treatment process transforms the treated wastewater into a safe, reliable drinking water supply. Unlike other potable reuse facilities in the United States, which return drinking water to a treatment plant or blend with other raw water sources, the Advanced Water Purification Facility will use a direct-to-distribution approach, with the purified water flowing directly into the drinking water distribution system.”
A pilot test successfully demonstrated that highly purified water can be consistently produced with this process: thousands of water samples were analyzed at state-certified laboratories showing that the purified water meets and performs better than all primary and secondary drinking water standards, El Paso Water says.
The Advanced Water Purification Facility is expected to produce up to 10 million gallons per day of water, and the city says it will get 6% of its water from advanced purification by 2030, CNN reports.
Challenges to Implementation
The introduction of such treated water – termed “direct potable reuse” – has faced multiple challenges in the past, including shifting regulations, cost of technology, complex treatment requirements, and public perception, according to the EPA.
Still, direct potable reuse is also growing internationally, and is expected to be an expanding part of global drinking water supply in the decades ahead. But advanced water treatment plants are complex and need to be designed correctly, operated effectively, and run with appropriate oversight, warned the Australian Academy of Technological Sciences and Engineering in a 2013 report (via the EPA). High levels of expertise and workforce training are critical, the report found.
While El Paso may become the first major city to use treated wastewater as drinking water, it won’t be the last. A recent report from Bluefield Research pointed out that, while most of the 735 reuse projects it tracked across the US were using reclaimed water for irrigation purposes, projects with potable applications, both direct and indirect, are continuing to gain traction, particularly in the core markets of California, Florida, Texas and Arizona.
Two cities that have implemented direct potable reuse projects in recent years include Big Spring, Texas, and Wichita Falls, Texas. Cloud Croft, New Mexico, recently permitted a direct potable reuse project in response to limited water sources for the seasonal tourist population, but it is not in operation, according to the EPA.