By Rachel Leven
With supplies of clean water becoming more scarce in certain areas and demand increasing, desalination is on the rise in the United States, water professionals told BNA.
Half again as many municipal desalination plants were built between 2000 and 2010 as were built in the preceding three decades, according to research by water sector consultant Mike Mickley that was published in 2012 in the IDA Journal of Desalination and Water Reuse, the journal of the International Desalination Association.
During that decade, 117 municipal desalination plants were constructed, bringing the total to 324 plants built since 1971, Mickley wrote in his article, “US Municipal Desalination Plants: Number, Types, Locations, Sizes, and Concentrate Management Practices.” Those figures include municipal plants with the capacity to produce 25,000 gallons per day or more of potable water.
Desalination grew significantly due to improved technology, a decline in cost, and dwindling supplies of water in the face of heightened demand, according to researchers, local water managers, and government officials. Many of these officials say desalination will continue to grow, although some are unsure if the industry will be able to overcome the hurdles posed by regulatory requirements. Most water professionals emphasized the need for desalination to play a key role in meeting future water needs.
“You can't conserve your way out of a water shortage completely,” Bob Yamada, water resources manager for San Diego County Water Authority, said. San Diego County will begin receiving water from a new desalination plant in Carlsbad, Calif., with a 50-million-gallon-per-day capacity by 2016.
The technology, which is widely used in many parts of the world--the Middle East is by far the largest market--has been slower to catch on in the United States, in part, because of regulatory restrictions, the high cost of energy needed to power the treatment plants, later need for the technology, and concerns about proper methods to dispose of the resulting salty waste.
In addition, the use of desalination--the process of turning salt or brackish water into freshwater--to provide clean water for drinking, industrial use, and irrigation lacks broad public support largely because of the significant amount of energy required and the questions about waste disposal.
Despite these hurdles, however, the United States ranks fourth among markets for desalinated water behind Saudi Arabia, the United Arab Emirates, and Spain, according to an International Desalination Association presentation from 2011.
Supporters of the technology say this “drought-proof tool” and the ability to tap new sources of water make desalination an enticing and necessary industry for the road ahead.
Desalination is best used as a part of an integrated water plan, water officials from San Diego, Tampa, Fla., and El Paso, Texas, told BNA. That means water management and conservation come first. Water reuse--or water that has been reclaimed through the wastewater treatment process, but may not be suitable for drinking or domestic use--can fulfill a need by providing supply for irrigation or industrial users. Desalination can supplement these measures to ensure an adequate supply of clean water.
Desalination and water reuse already play a significant role in addressing water supply needs, Mike Hightower, Sandia National Laboratories lead on an Energy Department project reviewing energy and water needs and issues, said. More than 40 percent of domestic supplies--water for drinking, cooking, and bathing, among other purposes--comes from desalination and wastewater reuse. That breaks down to roughly 30 percent from wastewater reuse and 13 percent from desalination nationwide, Hightower said.
“You can see already that even though people don't know it, desalination and wastewater reuse are a large percentage of the domestic [commercial and residential] water supply in the United States,” Hightower told BNA.
The number of desalination plants within the United States grows exponentially when industrial plants are considered because industrial facilities greatly outnumber municipal ones. A Pacific Institute study, Desalination, With a Grain of Salt, found there were roughly 2,000 desalination plants larger than 300,000 gallons per day operating in the United States as of 2005 when industrial plants are figured in.
There is little information available regarding private, industrial desalination plants, although the private sector typically has more funds available than municipalities. This means the industrial sector may have access to more expensive technologies and solutions than the municipal sector, Mickley told BNA.
Desalination has grown faster in certain states. As of 2010, Florida had the most municipal desalination plants with 148, followed by California at 45, Texas with 30, and North Carolina having 12, according to Mickley's paper. Mickley runs his own water and wastewater technology consulting firm and specializes in desalination and membrane technology.
In general, the technology is used in areas with inadequate supplies of clean water but where water resources that are of lower quality are available. Certain communities are better suited for desalination because of their proximity to a water resource not currently being tapped--either on the coast or near an inland brackish water resource, Sandia's Hightower told BNA.
Water officials for San Diego County Water Authority and Tampa Bay Water of Tampa, Fla., said that droughts during the 1990s and concern for future water resources sparked their cities' interest in desalination. In both cases, lower quality seawater nearby left communities with a more economical option to bring freshwater to their states.
Still, for many states desalination is the most expensive option.
Many desalination facilities spend roughly “one-third to one-half of operating cost” on the electricity to run the technology, according to a Congressional Research Service report, Desalination and Membrane Technologies: Federal Research and Adoption Issue.
Because desalination costs rise and fall with electricity costs, the price of desalination can be unpredictable, and because the most-used desalination technology in the United States, reverse osmosis, requires a large amount of energy to push pretreated water through a semipermeable membrane, the costs are high to begin with (2013 WLPM, 6/12/13).
However, for certain areas that are far from available sources of freshwater, desalination is the most economical option when compared with the cost of transporting water by pipe over long distances. That is the case in El Paso, Texas, according to Hightower, where the cost of importing freshwater might run as high as $6 to $7 per thousand gallons versus $4 to $5 per thousand gallons to desalinate.
“[Y]ou can see that having to build the infrastructure and pay for the energy to pump freshwater 200 miles or 150 miles is more expensive than using the brackish groundwater,” Hightower said.
Ed Archuleta, the former president and chief executive officer of El Paso Water Facilities told BNA that for El Paso, the cost of desalination is not that expensive compared with other alternatives, especially when it is spread across a large number of customers.
Water officials also can justify use of desalination because it is most effectively used as part of a larger water portfolio. Desalination tends to be the final option used to ensure freshwater to communities, officials said.
Archuleta said his community has focused on conserving water first, reusing and reclaiming water second, then using water from the nearby river, when it is available. However, when none of those are available, Archuleta pointed to desalination as El Paso's last resort.
The plant runs continuously, but desalinates different amounts of water depending on the need. For instance, during a drought, the plant runs near capacity, Archuleta said.
“We built [the plant] with three things in mind: current and future drought, dealing with growth in that part of the city, and any type of interruption to our other supplies where we would have to call on the desalination plant,” he told BNA.
The San Diego County Water Authority plans to use its facility as one of eight tools, including conservation, to ensure reliable water supplies to its constituents, according to data provided by Yamada. The authority will be adding a Poseidon Resources seawater desalination plant to its water portfolio by 2016, he said. The plant will supply approximately 56,000 acre-feet of water to the county in 2020, or roughly 7 percent of the 779,000 acre-feet the county is expected to use in 2020.
Michael Gabaldon, director of technical resources for the Interior Department's Bureau of Reclamation, said desalination's drought-proof quality makes it enticing for the federal water management plan, as well.
“Desalination and advanced water treatment just has to be a piece of that [portfolio] because that is the only place we are going to come up with a new water supply.” Gabaldon told BNA. He added that the bureau's main focus is to “sustai[n] the water we have.”
While many tout desalination's “drought-proof” benefits, others have expressed concern regarding the industry's environmental and public health impacts, in addition to the relatively high monetary costs.
Many desalination facilities run on fossil fuels, which generate greenhouse gases, according to the CRS report, although desalinating brackish water requires less energy than desalinating seawater. According to the Sierra Club's Lone Star Chapter in Texas, the increase in energy production--if not shifted to renewable energy such as wind or solar--would ultimately lead to increased pollution and greenhouse gas emissions. Nonetheless, the Lone Star Chapter in a 2008 report, Desalination: Is It Worth Its Salt?, said that desalination can be a suitable part of a water management plan, if used selectively and appropriately.
The national office of the organization has no position on the issue, a spokeswoman said.
Desalination facilities can also have adverse impacts on aquatic life in the areas near the intake pipes. Fish and other organisms can get sucked into the pipes or become trapped against the screens intended to filter material, the Lone Star Chapter report said. These could ultimately injure or kill the organisms, unless different technologies are used or the rate at which water is withdrawn is reduced.
Moreover, water that is not properly “post-treated” after desalination can be contaminated with harmful byproducts, such as brominated organic byproducts and chlorinated byproducts, or can be missing good components such as magnesium and calcium that were filtered out, the Lone Star Chapter report said.
Ultimately, many water associations are viewing how desalination actions today could affect the country's water supplies for the future. Water being pumped from the ground or the sea links to other freshwater resources and the environment overall, meaning drawing on groundwater for desalination may eventually affect a water source somewhere else. The effects are not necessarily clear, William Alley, National Ground Water Association director of science and technology and former U.S. Geological Survey Office of Groundwater chief, told BNA.
“Its a continuous resource, in a way. So when you develop the saline water you're going to draw on somewhere, maybe far away, on freshwater resources to some extent to replace that water that you're pulling out of the ground as saline water,” said Alley, whose organization has no position on the issue. “In some respects it's all one resource, although obviously if you're deep into a saline body, the effects are going to be minimal over a very long period of time.”
One of the largest concerns among desalination professionals is the disposal of concentrate generated through the treatment process. The concentrate encompasses a significant amount of salt waste that requires proper disposal.
If it is discharged to surface waters, according to the CRS report, it can pose risks to aquatic organisms. Finding an environmentally friendly way to dispose of the waste is one of the most costly aspects of desalination. Options range from using a pipeline to send the leftover salt out to sea and dispersing it to injecting the discharge into deep wells, Lisa Henthorne, former International Desalination Association president and director, said.
The Texas Sierra Club's report said that, if done correctly, these concerns could be mitigated and desalination could prove to be an asset. The report cautions that desalination should only be used in situations where it is the most “appropriate, environmentally sound and cost-effective tool,” however.
“With proper planning, siting, attention to all energy and environmental factors, and thorough evaluation of the full costs of operation, desalination plants could be a significant part of a comprehensive water supply program that also includes advanced water conservation and effective drought management measures,” the report said
The federal government and industry have worked to address these problems, finding ways to decrease costs, become energy efficient, harness renewable energy and reduce concentrate being released, water professionals said. Uniformity of water quality coming out of desalination plants has also improved, Harold Fravel, executive director of the American Membrane Technology Association, which represents a variety of groups from water suppliers to manufacturers, said.
For instance, plants, mostly outside the United States, are looking at how to harness renewable energy such as wind and solar power to power plants. Wind is being used to power a desalination plant in Australia, Archuleta said. Some of the United States' larger plants are also looking to use renewable energy, Henthorne said.
Approximately $56 million in federal funding was provided between 1998 and 2012 to augment desalination research, Robert Quint, senior adviser at the Bureau of Reclamation, said in recent congressional testimony. Desalination research, run largely by the bureau, has focused on brackish, inland water desalination.
Future research will likely examine environment, social and economic impacts, if any, and how those impacts can be minimized, Reclamation's Gabaldon said.
A bill (H.R. 745) sponsored by Rep. Grace Napolitano (D-Calif.) to reauthorize desalination funding for 2013 through 2018 is before the House Natural Resources Water and Power Subcommittee, which held a hearing on the bill in May (2013 WLPM, 5/29/13).
Future research is important because the tenets of desalination can apply to other water reclamation areas, such as reclaiming water from hydraulic fracking, Ben Grumbles, president of the U.S. Water Alliance and former assistant administrator for water with the Environmental Protection Agency, said.
Fracking leaves water that could be reclaimed and reused if salt and chemicals could be treated and removed out of the flowback water, Grumbles said, calling desalination research “an opportunity.”
“The big opportunity is to find affordable and environmentally protective ways to reclaim and reuse the large volumes of brackish frack water and other produced waters so they aren't simply discharged or buried as waste,” Grumbles told BNA. “This journey of produced water going from waste to wealth is closely related to desalination research and practice: Much of it can be boiled down to removing large amounts of salt without spending large amounts of money and energy.”
Despite these efforts, desalination proponents acknowledge that regulatory barriers could limit the growth of the industry. For instance, California requires 27 permits to site a desalination plant and the time line could take years, WateReuse President Wade Miller said.
Scott Maloni, a Poseidon Resources spokesman, told BNA in an email that the permitting process in California generally “has been time and labor intensive.”
The Carlsbad desalination plant's location was first identified in 1991, a San Diego County Water Authority presentation said. To open the plant, Poseidon Resources' proposal was vetted through a company study, two environmental impact reports, 12 discretionary local permits, seven state agency discretionary permits, 21 public hearings with a cumulative 85 hours of testimony, dozens of technical studies and 14 legal challenges and will open by 2016, according to the presentation.
The Carlsbad project “has provided a regulatory roadmap for streamlining the process,” Maloni said. Poseidon's second desalination plant, which will also have a capacity of 50 million gallons per day in Huntington Beach, Calif., in 2018, has had a much smoother time moving through the permitting process, he said.
However, the company would still like a more “one stop shop” permitting process for seawater desalination plants, like the power plant permitting process, he said. Whereas power plants apply once to the California Energy Commission, desalination plants need to go through at least six local, state and federal agencies, some with “overlapping jurisdictions, or at least [some that] suffer from mission creep that results in overlapping jurisdictions,” Maloni told BNA.
“This complex web of approvals is inefficient and unnecessary to ensure that projects comply with [applicable] environmental rules and regulations and serve to prolong the development process and drive up costs,” Maloni said.
This permitting and regulatory process will slow growth of the industry, especially compared to growth in other countries where desalination is widely used, Miller told BNA. Maloni also said while the Carlsbad and Huntington Beach projects have somewhat paved the way for future desalination plants, “[p]rivate companies and public agencies that lack wherewithal -financial, technical etc. - face a significant barrier to entry.”
Despite these concerns, a 2011 Bloomberg New Energy Finance study predicted the United States will likely have 8 percent of the world's desalination capacity by 2019. That would make the United States the region with the second largest desalination capacity, with the Middle East and North Africa's 79 percent of global capacity far out pacing the rest of the world, according to the study, No Added Salt: An Overview of Water Desalination.
Archuleta anticipates that many new facilities will be built over the next 20 years on the coast, while inland areas will see more new plants in the next 10 years. Fravel predicted two or three facilities would be built on the California coast alone in the next five to 10 years.
Fravel said that eventually the United States will need to tap new sources of water, and desalination will have to be one of the critical tools used.
“We're getting to a point where the sources have become more difficult to treat and conventional methods aren't going to work. As the population grows, and as we start seeing a shift in population location, I think they are going to rely heavily on technology to augment their water supplies,” Fravel said.