Desalination is a process that creates drinking-quality water by extracting salt and other minerals from seawater, brackish groundwater or treated waste water. Desalination yields between 15 to 50 percent of drinking water by volume of source water. The remainder ends up as waste, called “brine.” Technology has improved the efficiency of desalination plants, decreasing its costs up to 300 percent. There are many benefits to desalination that make it a promising technology for a world whose demand for clean water is ever-increasing.
The distribution systems required to pump water across entire states consume enormous amounts of energy and generate a great deal of air pollution. Strategic placement of desalination plants reduces these energy costs and lessens the environmental impact of water distribution. Although these benefits must be contrasted with the fact that the plants themselves require large amounts of electricity, advances have been made in plant design that reduce the environmental impact of desalination plants. The most significant of these improvements involves constructing desalination plants at the same location as power plants, where they have a symbiotic relationship, each mitigating the other’s environmental impact.
During times of severe drought, the water made available through desalination would protect against water shortages.
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Increased water supply from desalination plants would decrease the need for municipalities to re-route water that is needed for agriculture in times of water shortages.
Fish habitats are eroded when water from lakes, rivers and groundwater is diverted for human use. Increased volumes of water obtained through the desalination of seawater would allow for the restoration of these habitats. However, these benefits must be weighed against the destructive impact desalination plants have on the marine ecosystem.
For many coastal communities that have an inadequate local water supply, a desalination plant could free them from dependence on outside sources for their water. Local control of water resources is critical to a community’s ability to be self-sustaining.
When cities have diversified sources for water, they are less vulnerable to the fluctuations from any one source. This allows for greater economic stability for the municipalities, greater reliable availability and more consistent rates for the consumer.