Sea Water to Drink
Roberta Friedman
Technology Review, August/September 1989
As drought continues to threaten may regions, seawater is becoming a reasonable solution to the dearth of potable water. Once an exotic process limited to desert settlements and expensive island developments, desalination now appeals even to large cities.
Pouring out two billion gallons a day worldwide, desalination plants currently supply the needs of high technology, oil refineries and power plants. They also quench the thirst of entire communities. In Florida, which leads the United States in residential use, the largest of 110 desalination plants serves the city of Cape Coral, delivering 15 million gallons a day.
One reason for desalination’s increasing popularity is the steady decline in the amount of fuel it requires, which is the main cost of the process. Modern techniques generate 100 units of water for every unit of energy consumed. Four decades ago, rudimentary distillation took 25 units of energy to produce a unit of drinking water.