Thirsty city explores viability of saltwater, wastewater. (A Special Report: L.A.'s Search for Water).

IN order to survive in a desert, Los Angeles has always needed to be creative in managing its water needs.

Most of its efforts have focused on finding and developing traditional sources of water in the state's rivers, lakes and natural snowpack. But in recent years, more attention has been paid to alternative technologies to better use or re-use resources. Some technologies sound futuristic, such as desalination of seawater, but others are more manageable and built upon conservation principles.

Desalination has been the most obvious alternative considering L.A.'s coastal location. Up to now, its high cost had kept state and local officials from giving it serious thought, although new desalination processes have made it more feasible financially.

The Metropolitan Water District of Southern California is studying five proposals for seawater desalination plants, and a facility in El Segundo is already experimenting with the process.

New desalination process

The older desalination process involved boiling the water to a temperature high enough to eliminate harmful contaminants, but this became too expensive due to the high power costs needed for the process.

Newer plants are using a cheaper reverse osmosis process, which was developed at UCLA in the late 1960s as the main component of desalination.

Reverse osmosis, or "RO," works best in conjunction with a filtration and disinfectant process. Working in three stages, the seawater is brought into the plant and first goes through filters. Thin, straw-like filaments remove matter like plankton, protozoa and dirt but leaves the salt, said Paul Shoenberger, chief of engineering and operations at the West Basin Municipal Water District, which operates the El Segundo plant.

Next, the water is forced through membranes with high water pressure, leaving the salt behind.

Based on the water pressure and the size of openings in the membranes, the degree of salinity can be controlled. "Going in, the ocean water has 35,000 parts per million of salinity, and after reverse osmosis, has 350 parts per million," said Shoenberger. Typical drinking water has between 250 and 500 parts per million.

Lastly, the water is disinfected using chlorine or ultra violet light, and then can be consumed. A more immediate use is to inject it into the ground to protect ground water supplies from salt intrusion, said Tom West, an environmental engineer at water management consultant Camp Dresser & McKee.

Water recycling

A similar technology can be used in conjunction with wastewater treatment plants and is part of the more general concept of water recycling. Much of the water treated in this process is used for non-drinking purposes, such as industrial or agricultural uses. "It doesn't make sense to bring water in from miles away and throw it away after only one use," said Jerry Gewe, assistant general manager for water at the Los Angeles Department of Water and Power.

In some cases, the water is only given tertiary treatment, such as a filtration process to remove contaminants. Sometimes a biological process is applied, where water sits in ponds and natural bacteria naturally eliminate contaminants.

"Recycling works best when there is a close proximity between entities," said Gewe. For example, the Los Angeles/Glendale water treatment plant gets its water from the L.A. River, which is used to water golf courses that are right across the street.

Twenty years ago, the cost of treating water was in the range of $4,000 per acre foot. Evolving technology has made the process easier and cheaper, and recent projects have cost $800-900 per acre-foot, as compared to water from a utility company that averages $550 per acre-foot, said West. An acre-foot is enough to meet the water needs of two families for a year.

While water technologies continue to evolve, conservation efforts throughout Los Angeles have also progressed. "We're using the same amount of water we did 20 years ago even though the population has increased," said Shoenberger.

Tiered rate structures have been in place since 1992, where a higher cost is charged for a customer who uses more water. "This works to discourage excess water use," said Gewe.

Also in place are rebate programs where people are given $l00-$150 to replace their washing machines and toilets with water saving ones.

The use of "graywater" in homes is also being promoted by water officials. Such household systems collect water from showers or sinks, which is then used for non-drinking purposes like watering lawns.

Conservation efforts are even targeting the types of lawns and gardens Angelenos grow. "The goal is to develop gardens that require less water but still give us the lifestyle we want," Gewe said.

Will all that be enough?

Kevin Starr, the state librarian and professor in the School of Policy, Planning and Development at USC is skeptical. "Our state population in 2040 will be 60 million people, and the formula that is in place now is not going to work for that many people," he said. "We're going to have to grow in a more clustered and dense style, with more communal use of water and more use of graywater."

RELATED ARTICLE: The Users

FOR some L.A. companies, availability of enormous amounts of water means the difference between staying in business and shutting down. Some huge users have gone so far as to secure their own private sources, but even those aren't limitless, forcing them to go to the public sector if they run out.

Here's a look at three large users and how they keep the water flowing:

Descanso Gardens

With thousands of different species of flowers and plants, Descanso Gardens in La Canada Flintridge has been using a private 280-acre watershed in the San Gabriel Mountains for more than 60 years. The water in its buildings and drinking fountains, however, is supplied by water wholesaler Valley Water Co. in La Canada Flintridge.

The private wells flow water into a 60,000 gallon tank, which has a 178,000 gallon tank backup. It is then pumped into the garden's water system three miles away. Between 60,000-75,000 gallons of ranch water are used by the garden every day.

Once the water reaches the garden, it is pumped into the facility's circulating water systems. In addition to being used to water the landscape, the water fills its lakes, ponds and streams, which are home to fish and wildlife.

"Using the ranch water is cost effective, and it releases large amounts of public water for other purposes," said Descanso spokeswoman Avery Econome. Using a private supply saves Descanso $100,000 a year.

But the private reserve is not limitless and Descanso officials say they try to conserve by cultivating more drought resistant plants, as well as cutting by half the water for its 20-acre camellia grove, the world's largest. Horticulturists found that the flowers didn't need as much water as previously thought.

If the private supply of water should dry up, Descanso will turn to Valley Water Company, which buys its water from the Metropolitan Water District. But that has yet to happen. "We rely very little on public supply," said Econome.

Unified Western Grocers Inc.

This Commerce-based company, which also runs a dairy in Los Angeles, gets its water from the Los Angeles Department of Water and Power. The company uses 60 percent of its 80,000-100,000 gallons of water per day for such products as Tampico Citrus Punch and its own battled water--sold under the Springfield brand.

The rest of the water is used for cleaning its production facility. Every piece of equipment that comes into contact with its products must be sanitized, said John Bedrosian, vice president of manufacturing. "Without water we could not operate," he said.

The company has no alternative water sources and would suffer if there were any drastic rise in DWP rates. "We're dependent on them," said Bedrosian. "If they raised prices, we'd have no recourse but to pass the increase on."

The company has recently begun a conservation program that includes using less water in the washing of milk crates and other equipment. "For items that don't come in contact with food, we try to wash them with recycled water where we can." Bedrosian said.

Oil Refineries

Local refineries in the South Bay are among the largest users of water in Los Angeles. "Utilities are one of our biggest expenditures, and water is second after electricity," said Walter Neil, spokesman for BP Carson Refinery. The refinery uses five million gallons of water a day as part of the refining process.

About two-thirds of the refinery's water is bought from the California Water Service Co. of Torrance, a water wholesaler that gets its supply from the Metropolitan Water District.

But four years ago, the refinery began using recycled water from the Hyperion sewage treatment plant to cool gasoline in its "cooling towers." If Hyperion should ever have a problem, the refinery would revert to its other source. "Taking reclaimed water has helped drought-proof our neighbors," Neil said.

-- Samantha Lee