Computers Help Make Salt Water Into Fresh

ONE lone man is on site at a Canary Islands plant that transforms 60,000 gallons of sea water into drinkable water every day. Despite the plant's humming activity, the man may soon become bored, because this particular desalination system can virtually run by itself. The innovative plant, manufactured by Reliable Water Company of Billerica, Mass., uses artificial intelligence. The sophisticated ``machine instinct'' system requires no operators and has no man-powered valves, gauges, or controls. A conventional system similar to the Canary Island plant would need two or three operators.

Company officials say the elimination of extra manpower and human error means the plant can produce drinkable water 20 percent to 30 percent cheaper than conventional desalination systems. They predict their new system, despite its high capital cost, will eventually expand the desalination market.

``We're going to have something that no one else has,'' says Floyd Meller, vice-president of marketing at Reliable Water.

Desalination plants are common in Middle Eastern countries, particularly Saudi Arabia, and in arid areas where water supplies are scarce. There is also an increasing demand for desalination plants in southeastern and southwestern United States. The need is particularly great in Florida, where stressed aquifers produce a brackish, or salty, water supply, says Jim Birkett, desalination expert and former consultant for Arthur D. Little & Co. Inc. For the past three years, US demand for such plants has steadily increased, according to Mr. Birkett.

``The desalination market in the US has really taken off,'' he says.

The worldwide market has been expanding over the past five years, but it has started to slow down more recently, Birkett says. According to Leon Awerbuch, who works on desalination projects for Bechtel Group Inc., the Reliable Company plant won't change the desalination market as much as it will introduce cost-saving technology to the industry.

``It's clearly the most advanced technology related to the operation of desalination plants,'' Mr. Awerbuch says.

Such artificial intelligence technology allows the system to operate through its own built-in ``instincts,'' similar to that of an animal, say Reliable Company officials. Just as an animal has certain instincts to feed itself, escape from danger, and keep itself healthy, the Reliable Water desalination system operates with built-in instincts that monitor things like pressure, electrical current, temperature, and fluid flow. The system can make decisions about how to adjust to different situations and keep itself operating efficiently. The plant is also equipped with an alarm system to notify an operator if major adjustments must be made.

Company officials say the computer-controlled operation is far more reliable than conventional plants because human error is eliminated. Plant operators don't always perform 100 percent on the job, says Edward Fredkin, chairman and founder of Reliable Water Company.

Some industry specialists voice concerns about marketing the innovative system. Potential buyers in remote areas may be hesitant, because Reliable Water specialists are needed for repairing computer software. Furthermore, people in the industry may not be willing to invest in such a radically new system, says Birkett.

``People who invest in water plants tend not to take risks,'' Birkett says.

Some industry specialists are concerned about relying on a computer. Kent Nielsen, president of Omega Consulting Company, which does consulting work for water-treatment systems in the Caribbean, says computers are hard to maintain in the humid weather of the Caribbean. Computers must be kept in environmentally controlled rooms, he says, and power outages are frequent. ``You could have a major problem without the computer equipment,'' says Mr. Nielson.

Most experts agree, however, that Reliable Water has introduced a sound, technologically innovative system. The plant combines a filtering process called reverse osmosis with a new energy-recovery system. Sea water is pumped into the system, pressurized, and filtered through a membrane where the fresh water is separated. The pressurizing energy is then recovered from the brine, or salt-water residue, and used for the next batch of sea water. This recovery system reduces the amount of energy required to pressurize the sea water.

A small-sized Reliable Water plant produces 60,000 gallons of water a day and costs about $300,000. A similar conventional model costs between $200,000 to $220,000, say company officials.