Water Warriors

By Anne Burke

Published Jul 1, 2006 12:00 AM

YORAM COHEN LOOKS UP FROM THE PHONE. He's wearing an expression that says, "Wait 'til you hear this." Cohen is the director of the Water Technology Research Center at UCLA and one of the world's foremost experts on reverse-osmosis membrane desalination. He's talking to a developer who called looking for advice about installing a desalination plant at a housing tract in the San Joaquin Valley. Cohen finishes the conversation and chuckles.

"He wants to know if we're on top of our game!" One might ask if Kobe or Tiger is on top of his game. Cohen and his colleagues have put together the academic world's leading R&D program in reverse-osmosis, or "RO" membrane desalination — a process invented at UCLA nearly half a century ago.

RO desalination is the state-of-the-art technology for turning seawater and brackish water into fresh drinking water. But the process is still too problematic to be practical and economical for the parched masses. If we're going to meet the needs of a thirsty planet, we'll look to scientists like the 53-year-old Cohen (photo above) to help do it.

Freshwater Falloff

"Water, water, everywhere, nor any drop to drink," is as apt today as when Samuel Taylor Coleridge wrote "The Rime of the Ancient Mariner" in the 18th century. Seventy percent of the world's surface is covered in water, but only a tiny percentage of that is freshwater. Due to overconsumption, pollution and climate change, supplies of this most precious of natural resources are dwindling at an alarming rate.

Today, about 20 percent of the world's population lacks access to safe drinking water, according to the United Nations Environment Programme. More than 2.2 million people die each year from diseases associated with poor water and sanitary conditions, the UN reports. At any one time, half of the world's hospital beds are occupied by people suffering from waterborne diseases.

If present consumption patterns continue, two out of three people will live in water-stressed conditions by the year 2025, according to the UN's World Meteorological Organization. We can laugh at the chestnut attributed to Mark Twain — "Whiskey is for drinking, water is for fighting over" — but not at former World Bank Vice President Ismail Serageldin's unsettling prediction that the next world war will be fought not over oil or ideology, but water.

The Water Warriors

A professor of chemical engineering, Cohen was born in Israel and moved with his family to Canada at age 15. He did his doctoral work in polymer science and fluid mechanics at the University of Delaware. As a researcher and a human being, Cohen is mostly fearless. Solid as a linebacker even in middle age, he is a fifth-degree black belt and internationally known teacher of Shotokan karate, which he has studied since his teens. When he teaches karate, Cohen will look a student straight in the eye and say: "Go ahead and punch me as hard as you can." In science, if another researcher warns him, 'That won't work,' Cohen might try it anyway.

Cohen started the Water Technology Research Center, or WaTeR Center, last year with two colleagues in the Civil and Environmental Engineering Department, Julius "Bud" Glater, 85, an adjunct professor emeritus, and Eric Hoek, 34, an assistant professor. The WaTeR Center is a multidisciplinary effort with laboratories housed at the Henry Samueli School of Engineering and Applied Science.

Glater's involvement with desalination goes back to the Kennedy Administration, when the rallying cry to American scientists was, "Put a man on the moon and make the desert bloom." Though retired, Glater reports three or four days a week to his office in Boelter Hall, where he advises doctoral students, answers e-mail, and talks membrane science with Cohen, whom he describes as "one of the most brilliant guys I've ever worked with. He's got the energy of a 16-year-old — only he's focused!"

Hoek, who is from New Jersey, cared more about sports than academics in high school. But during an internship with the pharmaceutical giant Merck & Co. in college, he got turned on by chemical engineering. At UCLA, Hoek is exploring the next frontier of RO desalination, using nanotechnology to create membranes that are more efficient and use less energy. Hoek relishes the freedom that academia affords to explore uncharted territory and to seek answers to questions that no one else is even asking. "Sometimes," he says, "it's just too much fun."

The WaTeR Center got off the ground with $1 million from Proposition 50, the California clean water act, and another $1.6 million from private industry and other donors. The center's reach extends far beyond UCLA. Cohen, Glater and Hoek collaborate with researchers from other UC campuses as well as universities in the United States and abroad, major membrane manufacturers like Koch Membrane Systems and Hydranautics, and government agencies, among them the Metropolitan Water District of Southern California and the state Department of Water Resources.

Science for a Thirsty World

RO desalination uses extremely high pressure to force seawater or brackish water, which refers to high-salinity rivers and groundwater, through the pores of a semipermeable membrane. The pores are about one ten-thousandth of a micron — almost unfathomably small when you consider that a human hair is 50 microns in diameter. Water molecules under pressure can pass through these pores but not salt ions or other impurities, like bacteria.

Cohen, Hoek and Glater are working to minimize or eliminate the impediments to widespread use of RO desalination. The technology has been around for decades, but its major shortcoming is cost. The process requires huge amounts of electricity to force water through the membrane. Another big problem is so-called fouling and scaling, which is what happens when mineral salts, bacteria and other gunk collect on the membrane's surface and clog pores. Scaling puts higher energy demands on the system and leads to costly cleanup and replacement of membranes.

More problematic still is the somewhat paradoxical fact that desalination produces a high-saline waste stream that can be difficult to dispose of, especially for processing plants located a distance from the coast.

The WaTeR Center is involved in a number of experiments, but one of the most exciting will play out in the desert in Yuma, Ariz., where the Metropolitan Water District of Southern California is preparing to fire up a small demonstration plant to test a technology developed in Cohen's lab.

Cohen's technology is called "accelerated precipitation" and aims to achieve a 95 to 98-percent recovery of freshwater out of brackish water from the nearby Colorado River. The Colorado, the source for about half of Southern California's water, is growing increasingly salty due to agricultural and urban runoff. If the Yuma experiment is successful, the troublesome discharge stream would be only 2 to 5 percent of the input water — an amount so small it's practically unheard of in real-world membrane desalination applications. The process showed promise in Cohen's lab but the real test will come in the desert.

The technology would be used in a massive desalination plant that the Metropolitan Water District hopes to construct in coming years, probably along the Colorado River Aqueduct, says Christopher Gabelich M.S. '96, D.Env. '01, an environmental specialist with the Metropolitan Water District. The plant would produce three times as much freshwater as the world's largest desalination plant, located on the Mediterranean in Ashkelon, Israel.

Despite its many problems, interest in RO desalination has surged in the past decade as supplies of freshwater have dwindled and scientists like those at UCLA have produced incremental improvements in the technology. RO membrane desalination today is a $45-billion-dollar industry, with thousands of plants around the world. Most are in the oil-rich Arabian Peninsula. Texans make drinking water from the briny Brazos River using RO. The Florida Keys turns seawater into potable water through RO technology. RO is such an effective treatment that it can also be used to treat municipal wastewater and agricultural drainage water.

The state Department of Water Resources estimates that California will depend on desalinated water for 6 to 8 percent of its needs, which means that scientists like Cohen, Hoek and Glater have their work cut out for them. California currently has 23 desalination plants, most of them using RO technology, but they produce only a negligible amount of water. Some are small; others are hardly used at all. The city of Santa Barbara built an RO plant during the drought of the early 1990s, but due to high production costs, the plant sits idle until the next water emergency.

Another two dozen or more plants are in design-and-construction or drawing-board stages. The largest will be in Long Beach, where the city is preparing to test an unusual desalination process that would use significantly less energy than conventional methods.

Water Breakthrough in Westwood

What few people outside the desalination world know is that the technology behind RO membrane desalination was born at UCLA. The scientist recognized as the grandfather of the RO membrane process is Sidney Loeb M.S. '59, Ph.D. '64, who was a UCLA doctoral student when he and fellow graduate student Srinivasa Sourirajan serendipitously discovered an effective way to make RO membrane desalination effective.

"Come on, I want to show you something," Glater says, walking briskly to a lab in Boelter Hall where Loeb worked late into the night developing UCLA's celebrated RO membrane process.

Glater is a flesh-and-blood repository of UCLA engineering history. The story of the university's role in RO membrane desalination spills out of him in vivid detail.

In the 1950s, the U.S. government and the state of California, both concerned about depleting groundwater supplies, began funding research and development into low-cost desalination. One of the beneficiaries of government funding was UCLA, where a scientist named Gerald Hassler had been experimenting with desalting methods as early as the 1940s.

Back then, the leading technology for desalting water was distillation, in which saline water is heated to produce vapor, which condenses into freshwater. But Hassler had an idea to force water through a narrow air gap between the layers of synthetic film. Hassler's scheme, which relied on reverse osmosis, never worked well, but Glater points out that it laid the groundwork for Loeb's later accomplishments.

The Kansas-born Loeb had worked in private industry for many years before coming to UCLA in 1959, at age 41, to pursue a doctorate. He joined the lab of Professor Samuel Yuster, where Sourirajan was experimenting with little success on a desalination technique that involved pressurizing saltwater against a flat piece of cellulose acetate, the same stuff used to make motion picture film stock. The problem was that little freshwater came out the other side. "It was drip, drip, drip," Glater says.

Loeb and Sourirajan then experimented with different types of membranes under different temperatures, but the results were good and bad, seemingly at random. Loeb, who was the lead researcher, could have abandoned the project but kept at it. His perseverance paid off with a breakthrough when the two graduate students finally realized that the membrane side facing the air during casting on a glass plate had to be in contact with the saline solution for the process to work.

Yuster died in 1958, and Sourirajan left UCLA in 1961 to join Canada's National Research Council, where he did important work with membranes and kidney dialysis units, which require extremely pure water. Neither was around to watch UCLA make history by producing freshwater for a thirsty town in the San Joaquin Valley.

In 1965, every kitchen sink in tiny Coalinga, southwest of Fresno, had three water faucets — one for hot, one for cold and one for drinking water. Coalinga was not yet connected to the California Aqueduct, so potable water was hauled in on railroad cars. At that time, Loeb, then working under Professor Joseph W. McCutchan '39, M.S. '50, had been experimenting with membranes cast in long, metal tubes. When the two researchers went looking for a site to field-test this new RO equipment, Coalinga was happy to oblige. The Coalinga pilot project was the world's first commercial desalination plant, and produced 10,000 gallons of crystal-clear drinking water a day. In 1972, a canal finally arrived to bring freshwater to Coalinga, and UCLA turned over the plant to the city as a supplemental source.

Patents in those days not being what they are today, no one at UCLA made much money off Loeb and Sourirajan's discovery, Glater says. In 1967, Loeb went to Beersheva, Israel, to teach RO technology under the auspices of UNESCO. Now 89 and retired from a teaching position at Ben-Gurion University, Loeb lives modestly with his wife, Mickey. One of his pet peeves is bottled "spring" water, which is the same thing as RO desalinated water but hundreds of times as costly.

RO technology has progressed beyond the system that brought relief to Coalinga, but the challenges are much the same: how to make the process affordable and environmentally safe so that it's available to everyone. For Cohen, Hoek and Glater — UCLA's determined water warriors — it's the challenge of a lifetime.