A key issue that stands out is the low productivity or recovery that results in a large volume of concentrate, high-energy use, and relatively high treatment costs. A related major challenge is the disposal of the concentrate, in a cost-effective, environmentally sustainable manner—especially for inland sites. Currently the recovery from the conventional application of desalting processes, including reverse osmosis (RO), electrodialysis reversal (EDR), and thermal evaporation processes, is limited. Some 20 to 50 percent of the feed stream is wasted as byproduct or concentrate.
The disposal of such quantities of concentrate is not only a loss of valuable resource and energy, but also a challenge in itself—especially for inland facilities, and with regard to environmentally sustainable disposal options.