ONE of the attractive suggestions in the area of water usage proposed at January's Moscow peace conference on Middle East issues was the common construction of desalination plants.
The best possibility is an Israeli-Jordanian plant long planned for the border between Eilat and Aqaba. Yet this is only a drop in the bucket. The possibilities are unlimited. Desalination of sea water and mineral-rich water has been a solution to water shortages for decades.
Today there are about 7,500 desalination units around the world, treating 13 million cubic meters (17 million cubic yards) a day. Approximately two-thirds of these plants treat seawater, while one-quarter process mineral-rich water. Half of the production capacity is located in Persian Gulf states; 12 percent are in the United States.
Most of the countries in the Middle East do not have a shortage of water, says Israel's water controller, Prof. Dan Zaslavsky. In Iraq, Syria, Lebanon, and Egypt, the problem is inefficient water use rather than a shortage. Saudi Arabia and Libya lack water, but are rich in oil and can buy water. Only Jordan and Israel face significant water shortages.
This has led Israel to become a pioneer in desalination. Starting in 1965, the nation built 35 desalination facilities, which had a total annual production capacity of about 18 million cubic meters (24 million cubic yards), says Pinhas Glickstern, an engineer with Mekorot, the public company that supplies two-thirds of Israel's water.
Eight plants worked by vaporisation, 23 desalinated mineral-rich water by reverse osmosis, and four were experimental. Of these only the mineral-water plants are functioning today, producing 4 million cubic meters (5.2 million cubic yards) of water a year. Seawater desalination plants were gradually shut down in the 1980s because the mineral-water plants were much cheaper to run.
"Water desalination technology is capable today of producing limitless amounts of water at a price that makes it available for home or industrial usage," Dr. Zaslavsky says. The problem lies in energy, not in water production, he says.
The most common desalination technology is vaporization: multistage flash distillation or condensed-vapor refining. But a multistage plant is economical only when combined with power stations or when it is powered by a cheap energy source. Vapor refining may be useful if new plants prove to be energy efficient, Mr. Glickstern says.
While research into energy sources continues, the current high cost of energy has caused reverse-osmosis technology - a method of straining water through a permeable membrane - to be put forward as an alternative, Glickstern says.
Developments by Israeli, American, and Japanese companies have resulted in stronger, longer-lasting membranes. Additionally, energy-use improvements in the last decade have been incorporated into a Mekorot plant at Sabha, near Eilat. This plant, which produces 15,000 cubic meters of water daily, is remote controlled 14 hours a day and uses only half the energy such plants did 10 years ago.
Currently all commercial desalination plants in the world use conventional power sources, but energy research is making solar power feasible. Its inherent abilities to produce and store heat at high temperatures inexpensively give solar power advantages in seawater desalination. Mekorot's experts believe that soon solar desalination plants using reverse osmosis may be commercially attractive.
Desalinating seawater is only cost effective in quantities over 20,000 cubic meters per day. Desalinated seawater is available for 65 cents per cubic meter, but its estimated real cost is $1 per unit - both prices too high for agricultural use.
Mineral-rich water can be desalinated in any quantity for 25 cents to 45 cents per cubic meter, but Zaslavsky believes that rather than either of these, agriculture will use purified sewage water for many years.
During the next 20 years, he believes, inexpensive power sources will make it possible to produce desalinated seawater for 30 cents per cubic meter, one-third of the current cost. Desalination will also be the main method of purifying water contaminated by man-made chemicals.
But the Middle East will need large-scale desalination - tens of millions of cubic meters per year - not in 20 years time, but within three years, Zaslavsky says.
"If one wishes to make peace and bring prosperity to these countries, one must make sure that in the next decade 500 million to 600 million cubic meters of water will be desalinated. The investment needed for such a project is about $2.5 billion, less than the cost of a small war," he says.