Arizona Explores Desalination Options To Help Water Issue

By Mark Brodie
Published: Tuesday, July 16, 2019 - 11:55am
Updated: Tuesday, July 30, 2019 - 11:50am

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desalination equipment
U.S. Bureau of Reclamation
Desalination equipment.

MARK BRODIE: Most of Arizona is free of drought in the short-term, according to the State Department of Water Resources. Although long-term drought continues to affect the state. And, as other states and countries also deal with water scarcity. My next guest says desalination has become an increasingly popular option. Jim Robbins is a freelance journalist based in Helena, Montana, and has written about this. And, Jim, how big of an increase are we seeing in the use of desalination? 

JIM ROBBINS: Well, you're seeing a number... of large plants being built around the world. The big one, in North America, is the desal plant or desalination plant in Carlsbad near San Diego, which is a billion dollar facility and can produce 50 million gallons a day. They're building another similar sized plant in the same area of California or a similar area. And you've seen a lot of construction of big plants in Australia. Israel has embraced desal. They have a number of large plants. So, it's really growing. It's really seen as an important alternative, although an expensive one, for these countries that are facing water shortages.

BRODIE: Yeah, let me ask you about the economics of it. Because this technology has, obviously, been around for quite a while. I mean, there have been desalination plants... for many, many years. How have the economics changed to make it, maybe more palatable or at least more doable for some of these cities or countries?

ROBBINS: Well, one thing that's happened, is that the cost of desalination has come down in the last several decades. About half of what it was. But then the cost of other sources has gone up. San Diego for example, gets Colorado River water and it has to be pumped hundreds of miles and it's expensive. Electricity, is expensive for pumping water. And so it pays about $1,200 an acre foot, and desalination now is about twice that, for an acre foot. So, it's getting closer. The other big factor, is that it's certain. It's not something that's going to go away. Colorado River water across the Southwest, is threatened because of the shortage of water in Lake Mead. So, this is a way of assuring a supply, even if it costs twice as much. And... that's a very important factor.

BRODIE: Are there technologies or other ways of, maybe, bringing the price down even more, so that it becomes even more doable for municipalities or for governments?

ROBBINS: Yes, there's a number of new approaches to desalination that are being experimented with. The other thing that municipalities are looking at, is treatment of brackish water. Arizona in particular, is looking at, it has something like 600 million acre feet underground of brackish water deposits. And brackish water is quite a bit cheaper to treat than saltwater because there's less salt content.

BRODIE: You mentioned the Colorado River and the shortage that a lot of folks are saying is coming in the not too distant future. Arizona of course, relies in large part on the Colorado River. Is Arizona, do you think a good candidate for desalination technology?

ROBBINS: Well, it's certainly looking at it. I think it has to look for alternatives to... make sure its supply is certain. So what are their alternatives? Well, they've banked a lot of water underground but they are now looking at seriously, things like brackish water desalination and creating a water treatment facility with Mexico on the Gulf, California. People are thinking about it but I don't think the economics are there yet.

BRODIE: You also, in your article, write about some of the environmental impacts of desalination plants in the sense that, for one, they use a lot of energy which some might argue, almost kind of defeats the purpose of trying to use them as an environmental benefit.

ROBBINS: Right. I think about a third of the costs of a plant is the energy costs. And, you know, depending on where they get their energy, from a fossil fuel plant or something, it could contribute to climate change. That's what's going on in the Middle East, where they use more desalination plants than anywhere else. They have cheap fossil fuels, oil available there, and so the power is cheap. But they're, you know, contributing greenhouse gases from using all these desal plants. And, some experts warn that, as climate changes and places get drier and have to rely more on desalination, that...  you'll have a positive feedback loop where you build more plants, you create more climate change and it keeps going on and on. And so, there is some concern about that.

BRODIE: Within the industry, is there a sense of what the ultimate potential of desalination is? Like, is there somebody who predicts that "X" percent of drinking water in the U.S. or globally will be produced in desalination plants at some point down the road.

ROBBINS: I haven't heard a number of how much water will be produced in desalination plants. As far as I think right now, 300 million people get their water or their fresh water from desal plants. But it's definitely going... to grow. You have huge cities like, Cape Town in South Africa like, São Paulo in Brazil, it's just went through a drought, and on and on for whom water security is a serious problem. And when you start to look around there aren't too many alternatives for these large cities, except for desalination.

BRODIE: Jim Robbins, is a freelance journalist based in Helena, Montana. He talked about the potential for using desalination in Arizona and for more on that, I turn to Tom Buschatzke, director of the Arizona Department of Water Resources. And Tom, when you look at the list of potential solutions for Arizona's water issues, where is desalination on that list? How much potential do you think this method might actually have for the state?

THOMAS BUSCHATZKE: So, I think the potential for desalination to meet some of our future water needs is a very large potential. We do have areas within our state that have brackish groundwater that we could desalinate. And we are in discussions with Mexico about binational desalination opportunities in the Sea of Cortez.

BRODIE: When you talk about brackish water, I mean,... how much is there? And, what is the process for making that potable, relative to for example, ocean water?

BUSCHATZKE: So there are several areas in the state, that have large deposits and I don't have volumes for you of brackish groundwater. One in the West Valley, in the Yuma area and then kind of south of the Navajo reservation in northeastern Arizona. Those brackish groundwater desalination processes are actually cheaper than desalinating the ocean water because the salinity is lower. The big challenge, one of the big challenges there, is disposal of the brine. You cannot, obviously, dispose of it in an ocean when it's internal to Arizona. But there are methods that can be used to get rid of that brine but that's where... one of the bigger costs will come to the state, if we do in-state brackish groundwater desalination.

BRODIE: Do you see a potential future for the desal plant that's already built and has been sitting in Yuma for a number of years now?

BUSCHATZKE: So that plant, has challenges in terms of it being used. In any meaningful way for large quantities of water to be desalinated, it needs substantial upgrades in terms of infrastructure and some of that is for safety issues. I think the last number that I saw, just to get that plant back up to speed, was like, something like $25 million. The technology in that plant is very outdated. So it would be an expensive proposition. You do add the plant there itself, so that's an advantage. The federal government, in discussions with us, doesn't seem interested in investing in that plant or in those processes to use that plant in a meaningful way. And I don't think the states, in Arizona in particular, are really interested in doing a lot of the funding that would be necessary to move that plant. So there's lots of challenges with that Yuma plant. And, one of the challenges we have, in many of the areas within Arizona to do brackish groundwater desalinization, is the folks in the areas where that groundwater exists, are concerned about that groundwater being treated and potentially moved away from there area of origins. So, we need to in any project we might contemplate, look at area of origin impacts on the local areas where that groundwater exists.

BRODIE: Is the brackish water that's underground in Arizona currently being used for other purposes?

BUSCHATZKE: In some cases, it is. Some of it is still of good enough quality that it could be used and is used like in the West Valley. In some cases for irrigation, in some cases it's blended for other purposes. But in terms of drinking water, it certainly needs treatment to be able to be used for drinking water purposes.

BRODIE: Best case scenario, how much of a dent do you think that a plant like the one you're talking about with Mexico along the Sea of Cortez, could put in Arizona's water shortage problems?

BUSCHATZKE: It is helpful in solving the problem because there is no kind of low hanging fruit or one solution to those issues. Many different things are gonna have to be cobbled together. So, if you could do for example, 50,000 thousand acre feet that could come into central Arizona, that's a substantial volume of water, right? So, it would be one piece of various activities that would have to occur.

BRODIE: Is 50,000 acre feet a reasonable projection, do you think?

BUSCHATZKE: I think that is something that we can achieve and maybe even twice that.

BRODIE: Tom Buschatzke is director of the Arizona Department of Water Resources.


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