Fresh water sustains human life in a variety of ways. We need to drink it every day to replenish what we lose through perspiration and excretion. With few exceptions, all of the foods we consume, whether plant or animal, need abundant fresh water to grow. Not least, the virtually all of the living environment needs a supply of fresh water.
Israel desalinates water at a plant in the resort town of Eilat. But experts say desalinization in large enough quantities to matter to settlement areas is currently too expensive to consider.
Researchers at the University of Delaware have developed a simple and inexpensive device that uses wave energy to desalinate sea water. The device is called a Delbuoy ("Del" refers to the University of Delaware, and "buoy" refers to a buoy that rests on the water's surface). When the waves lift and then lower the buoy, a piston connected to the bottom of the buoy drives a pump at the sea's floor. The pressure created by the piston is strong enough to drive the sea water through a reverse osmosis filter, which removes salt and impurities from the water, and then to send the fresh water through a pipe to the shoreline, where it is tapped and used by people. Local divers with simple tools can install the devices in just ten minutes. The units cost little initially and can be maintained by trained local individuals. Best efficiencies are attained when the pump is deployed at depths of at least ten meters, and in the trade winds region from 30 degrees South to 30 degrees North latitude.
2. In developing countries, the costs of building and running a desalination plant are prohibitive. These are the same countries whose citizens bear the highest burden from water-borne diseases, and where the supply of fresh water for irrigation is most needed to help alleviate hunger.