ded to increase because of the increased levels of treatment being required in various countries to meet more stringent water quality standards. This rise in cost for conventionally treated water also is the result of an increased demand for water, leading to the need to develop more expensive conventional supplies, since the readily obtainable water sources have already been used.Many factors enter into the capital and operating costs for desalination: capacity and type of plants, plant location, feed water, labor, energy, financing, concentrate disposal, and plant reliability. In general, the cost of desalted seawater is about 3 to 5 times the cost of desalting brackish water from the same size plant. During the past decade in a number of areas of the USA, the economic cost of desalting brackish water has become less than the alternative of transferring large amounts of conventionally treated water by long-distance pipeline.In 1999 in the USA, the total production costs, including capital recovery, for brackish water systems with capacities of 4,000 to 40,000m3/d typically ranges from $0.25 to $0.60/m3 ($1.00 to $2.40/1000 gallons). In many recent privatized seawater-desalting plants ranging from 4,000 to 100,000 m3/d, the total cost of water estimated at $3 to $0.75 m3 ($12 to $.80/1000 gallons). These amounts give some idea of the range of costs involved, but the site-and country-specific factors will affect the actual costs. In any country or region, the economics of using desalination is not just the number of dollars, pesos, or dinars per cubic meter, but also the cost of desalted water versus the other alternatives. In many water-short areas, the cost of alternative sources of water is already very high and often above the cost of desalting. Any economic evaluation of the total cost of water delivered to a customer must include all the costs involved. This includes the costs for environmental protection (such as brine or concent...
