Zero Discharge Seawater Desalination: Integrating the Production of Freshwater, Salt, Magnesium, and Bromine. Desalination and Water Purification Research Development Program Report No. 111 Final rept

摘要

This report contains the results of a study of a zero liquid discharge (ZLD) process for seawater reverse osmosis (SWRO) with enhanced freshwater yield and production of salable sodium chloride (NaC1), magnesium hydroxide (Mg(OH)2), and bromine (Br2) from the SWRO reject. The process uses electrodialysis (ED) to reduce the salinity of the reject stream from SWRO so that the salt-depleted reject stream can be recycled to the SWRO to improve the yield of freshwater. The approach of this ZLD study is to remove in logical sequence the most accessible amounts of abundant constituents in seawater, water, and NaCl and leave remaining valuable constituents in a concentrated solution. After recovery of the niost accessible portions of water (NaC1, Brg and Mg(OH)2), the residual solutions can be evaporated to dryness to produce road salt; but ultimately, minor constituents might be recovered from that residue.