Las Vegas Sun

January 27, 2022

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Desalination may be solution to water woes of LV Valley

Water, water, everywhere, but not a drop to drink?


The technology of desalination, or desalting seawater, has helped Middle Eastern deserts and Caribbean islands bloom. And that technology may eventually help Las Vegas keep blooming.

Southern Nevada Water Authority General Manager Pat Mulroy said that the long-term needs of the region will not be sustained by her agency's plan to pump water from Nevada's rural counties.

"The only factor that acts almost as a pressure relief valve is large desalting facilities," Mulroy said at a recent conference on Colorado River water.

Mulroy says desalting ocean water will be an important part of the region's water plan. Water officials could count on it as a consistent source of water.

The thinking is that the Water Authority would fund desalination projects along the Pacific, and give that water to California agencies in exchange for their draw from the Colorado River.

Desalting is still very expensive compared with other water sources, Mulroy said, but "it is a safety valve."

Desalting is the wave of the future, although it might not be the immediate future, experts say.

"In 75 years there will be a large or several large desalting facilities on the Pacific Ocean," Mulroy predicted.

But not everyone is as sanguine about the future of desalting. While the technology is touted by Las Vegas environmentalists as an alternative to pumping rural groundwater south, their brethren on the coast are generally opposed to the processes.

The environmentalists have two reasons for opposing desalting plants along the Pacific coast. One is that the processes to take salt out of water, which boil down to either a membrane-based system such as reverse osmosis or distillation through heating and condensation, take huge amounts of potentially pollution-producing energy.

The second issue for environmentalists, however, is the more significant. Desalting produces good, clean water, but it also produces a salty slurry of brine.

Smaller amounts of brine can be disposed of in the ocean, but the more brine there is, the more difficult it is to get rid of it without affecting the environment.

Glen Peterson of the Metropolitan Water District of Southern California, which brings water to more than 20 million people, said the resistance to desalting plants on the coast will continue.

Environmentalists, a potent political force in California, have successfully lobbied the state's coastal commission to block more desalting plants. Approval for such projects would need to come from the commission.

"I think you have a real, real hard thing to fight to get the California Coastal Commission approval on this," Peterson said.

The coastal commission, however, has approved some desalting plants. There are 11 approved plants, but their total production is a paltry 3,300 acre-feet of water per year.

In contrast, Clark County takes 300,000 acre-feet a year from Lake Mead to sustain the urban population. An acre-foot is about 326,000 gallons.

Proposals to build another 21 plants are in various stages. If built, those plants could provide 260,000 acre-feet annually. Peterson, however, said he doesn't believe all of those plants will be built because of environmental and economic obstacles.

Water Authority Resources Manager Ken Albright recently echoed the point on the economics of the issue.

In 2003 the California Coastal Commission reported the estimated costs for five proposed desalting plants in Southern California would range from $62 million for a plant in Long Beach to $272 million for a project in San Diego.

The cost for desalting water is $800 to $1,200 an acre-foot, depending on the type of technology, the energy source and other factors.

The Southern Nevada Water Authority, for example, spends about $250 for an acre-foot of water from Lake Mead. That includes the cost to buy the water, pump the water and deliver it to municipal providers.

There are some advantages for desalted water, said Anatole Falagan, Metropolitan Water District assistant manager for water resource management. A primary advantage is that despite the cost, desalted water is far less susceptible to fluctuations that threaten the Colorado River, such as drought.

Falagan believes that a goal of taking 150,000 acre-feet of desalted water by 2025 is realistic. Already, the plants on the drawing board would provide 140,000 acre-feet by 2025.

"We're almost there," he said. The agency's overall demand is 5 million acre-feet, but because it can count on the water, "it is an important part of our portfolio."

Falagan said that the environmental problems can be overcome. Brine can be pumped underneath the ocean floor, or mixed with sewage outfall to the ocean to replicate the ocean's natural salinity.

Supporters of the process say there are benefits -- seawater is rich not just in salt, which could be sold, but also in other materials that have value. Some also believe the cost of the process is going to go down as more plants are built and the technology is refined.

"There are a lot of good scientists out there with a lot of good ideas ... There are avenues for people to pursue their dreams and their research," Albright said.

That means there are millions in federal and state funding, with agencies looking for promising new technologies and research to support, he said.

"If somebody's got the idea, the silver bullet, something is wrong if we're not all jumping on board."

Albright, however, said he believes that the day will come when the Water Authority helps build and operate a plant on the Pacific Ocean and swap that water with California's Colorado River allocation.

McClain Peterson, an analyst with Nevada's Colorado River Commission, said he is not sure when that day will come. Peterson's agency is charged with negotiating river issues with the other six states of the Colorado River basin.

"It's hard to guess. To know that answer, you have to know a lot about the politics of California. We will see it in our portfolio in our future, but it may not be for another decade or so. A plant would take four years to build anyway."

Launce Rake can be reached at 259-4127 or at [email protected]

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