A looming global crisis exists with a critical need for a clean water supply for household use in many of the world’s population centers; with the majority of the earth’s surface devoted to seawater, it is only natural that desalination efforts extend far inland. Modern desalination techniques make it possible to produce clean water, but the reject brine produced by the process must be either returned to the ocean or treated in some way that prevents damage to surrounding soils and contamination of existing underground stores of pure water. That is made possible when the concentrate, or “wastewater” used to remove salt from ocean water, can be allowed to evaporate naturally, leaving behind only a fraction of the brine volume to be disposed of by another method.
In arid, sunny climates there is an abundance of solar energy, and evaporation is a relatively speedy and cost-effective way to minimize the volume of the reject brine. Evaporation ponds are also suitable in areas with existing groundwater salinity readings that are too high for extensive irrigation. This is true in areas with a shallow water table. Saline water tables can be lowered by pumping or tile draining, with the drainage water stored in evaporation ponds, for beneficial effect both environmentally and economically. Additional research and new methods should be undertaken to ensure that the global water supply can keep pace with the need, particularly in developing areas. While the need for pure drinking water is critical to human health, there is also a need for water for irrigation, sanitation and commercial development.
