Much of the world including parts of the United state suffer form chronic shortage of water. throughout history, water used by human has come from freshwater groundwater and surface sources relying on nature hydrologic cycle for purification to remove dissolve salt. largely untapped is the more than 97% of earth water that is to saline aquifer. Assuming sufficient availability affordable energy, these water can be subject to desalination to provide freshwater suitable for human consumption and irrigation.