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In a region as drought-prone as New Mexico, every drop counts. But what if we were to tell you that many inland regions in the US, including New Mexico, are also home to abundant, untapped reserves that can solve their water needs in more ways than one?
Growing research for freshwater alternatives and technological advancements have made underground sources of brackish water a potential game-changer. Through desalination, this salty, naturally occurring water can be transformed into a viable solution for water scarcity.
In this blog, we share more about this unconventional water resource and Undesert’s contribution toward its sustainable desalination and reuse.
What is Saline and What is Brackish Water?
Although often used interchangeably, saline and brackish water are quite different. Saline typically has a total dissolved solids (TDS) volume exceeding 10,000 mg/L.
Brackish water, on the other hand, has a higher dissolved salt content than freshwater but lower than that of seawater. The TDS present in brackish water lie somewhere between 1,000 to 10,000 mg/L (milligrams per liter). It is a naturally occurring resource and can be found on the surface of estuaries or in deep aquifers.
And just to clarify, the EPA says water with TDS less than 500 mg/L to be fit for human consumption. Anything above a TDS of 1,000 mg/L is not even acceptable for agriculture as it can impede plant growth and impact soil health.
How Much Brackish Water is Stored Underground?
The American Southwest is endowed with large aquifers of very salty groundwater. Texas, for example, has a staggering 2.7 billion acre-feet of brackish groundwater, which still pales in comparison to New Mexico, with its 15 billion acres of brackish and saline underground water stored at depths below 3,000 feet.
According to the New Mexico Desalination Association, with proper desalination treatment, these expansive stores of groundwater have the potential to augment municipal water and possibly cater to a 1000-year supply of water at 2018 consumption levels. In its efforts to expand the water supply, the landlocked state recently announced an investment of $500 million towards purchasing treated brackish water and produced water.
However, making this highly saline and dense water suitable for human and agricultural consumption is replete with challenges.
Addressing Challenges in Making Saline Groundwater Fit for Reuse
As promising as desalination is, several operational and environmental challenges plague most commercially available treatment systems. Innovative treatment techniques such as Undesert’s Salty Wastewater Purification (SWAP) are essential to address aridity and water scarcity in a sustainable way.
Recovery Efficiency and Brine Management
Current desalination technologies have a recovery rate of only 60-85%, leaving a substantial volume of salt-rich brine to tackle. In the case of inland regions like New Mexico, brine disposal can take place through surface water discharge, sewer discharge, or large evaporation ponds, which may contaminate freshwater stores and soil.
A more environmentally acceptable way of treating this water involves improving recovery efficiencies significantly. Undesert’s SWAP device recovers more than 93% of saline or brackish water, leaving no harmful residue, only ultra-pure water and dry salt. SWAP’s high recovery efficiency not only reduces disposal volumes but also extends the supply of brackish groundwater - an expansive but finite resource.
Energy Consumption
Another challenge associated with current desalination systems is their high energy consumption. Their energy-guzzling pumps and membranes increase the cost of operations, not to mention the environmental impact and carbon emissions.
In an effort to treat brackish water more sustainably, Undesert has designed a hybrid energy system that uses a modular design and energy recycling to capture, desalinate, and condense efficiently. The entire process consumes very little purchased energy and has a low carbon footprint. It can also be capable of operating independently and off-grid.
Undesert: Our Role in Sustainable Reuse of Underground Brackish Water
The looming freshwater scarcity underscores the need to use water as judiciously as possible, including the reuse of treated salty groundwater. This previously overlooked resource has the potential to support agriculture efforts and combat desertification.
At Undesert, we are committed to the cause. Our SWAP device is twice as energy efficient and can purify contaminated or brackish water four times more concentrated than reverse osmosis can.
The recent surge in public investments is a clear signal of New Mexico’s intensifying efforts toward water self-sufficiency. And at Undesert, we are equipped with the right technology and vision to support this quest.
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