Experts Weigh Desalination’s Promise, Impact

For nearly a century, Southern Californians have outwitted their climate, going to extraordinary lengths to quench an enormous thirst. We have punched holes through mountains, carved channels in the desert floor, drained distant rivers and lakes and lifted water up steep passes.

Yet after all these Herculean efforts, perhaps the simplest and only drought-proof option for overcoming the chronic water shortage lies right at our doorstep, in the vast, salty Pacific Ocean. In a relentless hunt for new sources of drinking water, communities from Monterey to San Diego are now casting an eye toward ocean waters, their most abundant resource.

The giant Metropolitan Water District hopes to build one of the world’s largest seawater desalination plants--producing 80 million gallons of fresh water daily--somewhere on the Southern California shoreline by 1997. At least seven others are proposed along the southern and central coast, including Huntington Beach, Ventura and San Diego Bay, while three already began operating in the past year in Santa Barbara and Morro Bay and on Santa Catalina Island.

But this sudden flurry of proposals has triggered worries that the long-term ecological effects of transforming seawater to tap water are poorly understood, and that the push to find new sources might result in ill-conceived projects.

Marine researchers and state authorities are warning that serious questions about the impacts of these surf-to-sink operations remain unanswered, from their repercussions on fish to their contribution to smog.

Each day, a desalting plant pumps millions of gallons of brine--a dense, super-salty solution--into the ocean or its bays, where it might harm creatures that are vital links in the sea’s chain of life.

“Disposal of brine is a new concept, and it is the area (of desalination) with the most potential for problems,” said John Largier, an assistant research oceanographer with the Scripps Institution of Oceanography at UC San Diego. “We understand a lot of the physics, but we don’t understand all of it. There are things that would have to be watched, subtle things you wouldn’t readily notice.”

Marine experts and environmentalists have learned the hard way how vulnerable the ocean ecosystem can be to imperfect human engineering.

Two decades ago, a desalination plant in Key West, Fla., the first large one built in the United States, silently poisoned marine life in a popular shrimping harbor. Dead clams and oysters littered the water, other species vanished entirely and some small fish suffered liver lesions. The toxic poisoning went undetected for several years before researchers discovered copper equipment was corroding from the brine. The plant was eventually shut down and rebuilt.

Although everyone learned from that episode to avoid using copper, other questions remain, especially concerning the concentrated salt disposed of in the ocean.

Ocean creatures--which are ultra-sensitive to slight changes in salinity, light, temperature, oxygen and turbidity--could be poisoned or smothered if the heavy brine settles on the bottom. And when pumped into sheltered waters, large volumes of brine might overpower a bay or estuary with salt or alter the direction of its currents, which in turn would reshape its entire ecosystem. Also, drawing in millions of gallons of seawater would trap fish and their eggs.

Spills of hazardous chemicals--such as chlorine and acids--also are possible, although considered unlikely by many engineers, while still others worry that the industrial plants will be an ugly, noisy blight on an already cluttered coastline.

Desalination plants consume so much energy that they could contribute to smog--the Southland’s most vexing environmental problem--and increase carbon dioxide from power plants, which some scientists say causes global warming. Producing just 1,000 gallons of desalted water would use as much electricity as an average California household consumes in a day.

“The urban coastal zone is already under tremendous assault, so we must do this very slowly,” said Bob Sulnick, executive director of American Oceans Campaign, a Santa Monica-based environmental group.

“I’m not opposing desalination,” he said. “We are having a freshwater crisis and it certainly needs to be considered very seriously. But what concerns me in this engineering of nature is that (proponents) get a point of view, and then try to go out and prove it. The environmental review and analysis must be done very thoroughly.”

Despite the uncertainties and drawbacks, Southern California water suppliers maintain that desalination is probably the most benign of all the alternatives for new water supplies, such as building more canals to drain the ailing Sacramento-San Joaquin River Delta.

“With the apparent benefits and the minimal impacts, it looks like a good deal. But, admittedly, we haven’t done work on the environmental impacts yet,” said Mark Skowronski, a senior research scientist at Southern California Edison. The utility built a small desalination plant on Santa Catalina Island last year and is now teaming with the Metropolitan Water District to plan a larger demonstration plant next to its Huntington Beach electric plant.

“I can’t see where there would be any significant effects on the ocean, given the low increases in salinity,” Skowronski said. “In fact, a very serious concern is the opposite--we have to be very careful as to the quality of the water coming into the plant, since the ocean contains bacteria and other substances.”

For decades, seawater desalination was considered an exotic, prohibitively expensive source of drinking water. But with traditional sources plagued by drought and projected to double in cost, desalination is now beginning to emerge as a credible option in Southern California.

If all eight of the proposed ventures are built, about 190 million gallons of water would be sucked from the ocean each day--supplying about 4% of Southern California’s water--while the plants would pump back an estimated 65 million gallons of brine daily.

Normal ocean waters are about 3.3% saline, while the brine is 4.4% to 8%--about the same concentration as if 100 buckets of salt were tossed into a large swimming pool.

The extra salinity would be fatal to marine life, especially the small, floor-dwelling animals and plants that provide food for larger species.

“With brine, if it doesn’t mix properly, it will go to the bottom and sort of spread out like a carpet. These animals are used to having so much salinity in their seawater, just like we’re used to having so much oxygen in our air, so if the salinity is too high, it’s a poison,” said Largier of the Scripps Institution of Oceanography.

The key question is, would the salty plume dissolve within a few feet and have minimal impact, or encompass a much larger portion of the local marine ecosystem, known as the Southern California Bight?

No one is quite sure. Early computer models at moderately sized desalination plants, such as the new one in Santa Barbara, show ocean waters are impacted within about 120 feet of the pipeline, said Michael Higgins, an associate engineer at the state’s San Luis Obispo regional water board. The potential effects of larger plants, however, have not been studied.

Many marine experts, including Largier, believe the discharge would mix so quickly in the open ocean that the salt would be almost instantly undetectable. But they acknowledge they are only speculating, and that no one really knows how it will react, especially over time.

Even in Saudi Arabia, which leads the world in the number of desalination plants with 22, government engineer Abdul Jalil I. Mannaa acknowledges that “more studies are still needed to show the long-term impact . . . on the marine life and ecosystem.”

Extracting salt from water dates back to Aristotle, and has been used widely throughout the Middle East since the late 1960s. Salt can be removed by two fairly simple technologies: distillation--injecting steam; or reverse osmosis--squeezing it through filtering membranes.

The cost, however, has always been prohibitively high--$3 to $6 per 1,000 gallons of water, a rate three to seven times higher than Southern California’s imported water. But the price of the region’s traditional water supplies is expected to double by 1998 and recent cost-saving advances have been made in desalting, so that gap is shrinking.

Largely, it took an unforeseen force for seawater to surface as a true option for California: Six consecutive dry years that have left the state’s major reservoirs half-empty.

Traditional sources are becoming more and more restricted--both by law and nature--while Southern California continues to grow. New water-transport projects are often blocked by laws protecting endangered species and wetlands, as well as strong public disapproval.

Serious consideration of desalination is so new that California has no definitive policies to address it. The California Coastal Commission, State Water Resources Control Board and other regulators have just begun to fashion ground rules for granting or denying permission.

A new report about to be completed by the Coastal Commission’s staff will raise red flags, especially about the brine disposal, large-scale energy use and growth-inducing impacts new water supplies would have on coastal cities. The agency would look most unfavorably on desalting plants near kelp beds or other sensitive marine areas and on construction of new ocean pipelines, as opposed to use of existing ones at electric-power and sewage-treatment plants.

“We would particularly look at where a plant is located,” said Cy Oggins, a Coastal Commission staffer. “We would be concerned if it is sited in an area of biological significance, such as the new marine sanctuary off Monterey.”

The giant plant the Metropolitan Water District would like to build by 1997--next to an undetermined power plant between Ventura and San Diego--would unload 40 million gallons of brine daily into the ocean.

Marine researchers say brine from even the largest desalting operation is a drop in the ocean compared to billions of gallons of urban runoff, power plant discharge and treated sewage that already flows daily into the Pacific from Southern California. A single power plant in one day releases up to half a billion gallons of hot water used to create steam and run generators.

“It’s just a bump on a much bigger mountain range. A much more significant problem is surface runoff, which is toxic. With desalination, you’re talking about adding brine, which is essentially salt,” said Jeffrey Cross, director of the Southern California Coastal Water Research Project, a group of scientists assembled by local governments which studies the impact of ocean waste disposal on marine life.

Cross notes, however, that while he believes pumping it into the open ocean would have minimal impact, “I would have concerns in an enclosed bay. It’s like putting the discharge into a lake instead of the ocean--the denser stuff is going to sink.”

Some environmentalists say it is ludicrous to call the brine insignificant just because larger amounts of worse wastes are already dumped in the ocean. “Anything in great quantity is a potential problem,” Sulnick said.

Gordon Hess, resources planning director at the San Diego County Water Authority, said engineers are performing computer modeling to see if a proposed 30-million-gallon-per-day desalting operation next to a power plant in Chula Vista would harm San Diego Bay.

“We need to figure out what incremental impact it would have on the bay’s total salinity,” Hess said. “One option we have is to haul the brine to a nearby salt company. But that is a partial solution, since it couldn’t handle all of it.”

The environmental challenges aren’t necessarily insurmountable. In fact, modern engineering can probably resolve many of the threats.

The trick, however, is to protect the environment without inflicting an exorbitant price tag that would make desalting unaffordable. “It can be done. But it’s the cost that’s a concern,” said David Dean, a mechanical engineer at Metropolitan.

To minimize the environmental impacts as well as the cost, most proposed desalting operations, including ones in Huntington Beach and San Diego Bay, would be paired with coastal electric plants. The brine could then be diluted with power plant discharges--bringing both closer in content to ocean waters before it is pumped out.

Teaming desalting operations with power plants also reduces energy needs, eliminates problems in purchasing beachfront land, and means no new intake and discharge pipelines would disrupt the ocean.

“It’s far, far easier to amend an existing permit than to purchase virgin coastline. Our sites have already been used for industrial purposes,” said Skowronski of Edison.

Dean said air pollution will be a major obstacle, since desalination requires large amounts of electricity, which in turn releases nitrogen oxides--a main ingredient in the Los Angeles basin’s smog.

One solution is building the desalting operations at several power plants in Los Angeles County and Huntington Beach that already are mandated to install equipment that cuts air emissions by 90%. Even then, air-quality concerns remain because a power plant would have to operate at close to 100% of capacity--about five times more often than now.

Still, whenever harvesting more water, sacrifices are inevitable.

“If we are going to have a civilization like this, we’re going to have wastes, which means we have to accept some type of environmental degradation,” Cross said. “And they can only go three places--into the water, the air or the land.”

FROM Surf TO Sink

Turning seawater into tap water seems to be a simple, plentiful solution to local water woes. However, desalination costs are high, the contribution to the water supply minimal and the environmental impact uncertain.

Environmental Concerns

Little is known about how desalination affects the ocean, even though countries such as Saudi Arabia have used it for years. Some concerns and possible solutions:

1) Intake

Concern: Fish, other marine life get sucked into pipes during intake of seawater.

Impact: Might be marginal. Existing power plants draw more water than desalination plants, yet are relatively benign.

2) Pipelines

Concern: Copper, other harmful metals could corrode and be discharged into ocean.

Solution: Use safer materials, such as polyethylene or aluminum.

3) Chemicals

Concern: Chlorine and other toxic chemicals used to treat seawater and clean equipment could spill into the ocean.

Solution: Leak-detection, spill-containment systems could minimize chance of accidents. New technologies could reduce need for harsh chemicals.

4) Air Pollution

Concern: Producing electricity to desalt water would emit smog-causing fumes and global-warming gases.

Solution: Desalination plants could be teamed with power plants that are being equipped with gas turbines to cut emissions 90%.

5) Brine Discharge

Concerns for marine life:

* High salt content.

* Brine could sink and agitate ocean floor sediments, blocking sunlight.

* Metals normally diluted in seawater could become concentrated and poisonous.

* Low oxygen content.

* Discharge could alter currents and circulation patterns in bays and estuaries.

Solution: Mix brine with waste water from power or sewage plants, making it more buoyant, and diluting salt and metals. Avoid discharging into bays or other sensitive waters.

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How Desalination Works

There are two main methods of turning seawater into drinking water.

Reverse osmosis: Seawater is forced through a filter that traps salts, producing fresh water.

Distillation: Seawater is boiled, producing salt-free steam that condenses into fresh water.

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How Salty Is Water?

Saltiness for five gallons of: Tap water: About 1 tablespoon Ocean water: About 3 cups Brine: About 5 cups *

Where Plants Are in California

The Metropolitan Water District may build an 80-million-gallons-a-day desalination plant in 1997 at a power plant somewhere along Southern California’s coast, after building a 5-million-gallon-a-day test plant in Huntington Beach, perhaps in 1994. Other plants in gallons per day: Existing San Simeon: 40,000 gallons Morro Bay: 600,000 gallons Santa Barbara: 6.7 million gallons San Nicholas Island: 24,000 gallons Santa Catalina Island: 132,000 gallons Proposed Sand City: 20,000 gallons Monterey Bay Aquarium: 43,000 gallons Monterey: 3 million to 7 million gallons Lompoc: 326,000 to 1.3 million gallons Ventura: 6 million gallons Huntington Beach: 5 million gallons San Diego Bay: 30 million gallons Note: Several small offshore oil platform plants not shown.

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World’s Largest Desalination Plants By gallons of water produced per day: 1) Al Jubail, Saudi Arabia: 288 million gallons 2) Doha West, Kuwait: 115 million gallons 3) Abu Dhabi, United Arab Emirates: 91 million gallons 4) Az-Zour South, Kuwait: 77 million gallons 5) Dubai, United Arab Emirates: 72 million gallons *

A Partial Solution

Proposed desalination plants won’t eliminate Southern California’s dependency on water imports, but will provide a drought-proof, albeit expensive, source of water:

A Drop in the Bucket

Proposed desalination plants would provide only 3% of the region’s daily water needs*. Gallons per day (Current sources) Total daily use: 3.6 billion Imported: 2.2 billion Local: 1.2 billion Reclaimed: 205 million From desalination: 121 million * For urban portions of Los Angeles, Orange, San Diego, Riverside, San Bernardino and Ventura counties

Costly Now, Cheaper Later

Technological advances are expected to bring desalination costs down. Cost of 1,000 gallons Local: $0.34 Imported: $1.00 Reclaimed: $1.69 Desalination: $4.60 Tankered water: $7.67 Alaskan Pipeline: $12.27 Note: 1992 costs; may vary depending on project or other factors

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Sea Life: Bottom-Dwellers at Risk?

If brine from desalination plants has adverse effects, scientists expect creatures on the ocean floor would be the most vulnerable. A sampling of sea-bottom life common to local waters:

Eccentric sand dollars: Five “petals” on top are where breathing tubes emerge from shell.

Hermit crab: Has no shell, instead uses empty snail shells for protection.

Queenfish: Often the most common catch by pier anglers.

Dwarf brittle star: This creature can emit light from its body.

Northern anchovy: Commercially caught and important food for other fish, birds, mammals.

California halibut: Popular commercial and sport fish, with eyes on top side of body.

Sources: “Seawater Desalination in California,” California Coastal Commission; “Economic and Environmental Considerations of Seawater Desalination in California,” General Atomics; “Ocean to Faucet,” California Coast and Ocean; Metropolitan Water District; Municipal Water District of Orange County; International Desalination Assn.; Orange Coast College Prof. Dennis Kelley; “Pacific Intertidal Life”; Audubon’s “Pacific Coast”; “Marine Sportfish Identification.”

Researched By DANNY SULLIVAN and MARLA CONE / Los Angeles Times