DESALINATION OF BRACKISH WATER OF HIGHER SALINITY BY ELECTRODIALYSIS

A laboratory model electrodialysis(ED) stack containing 35 cell pairs Of Cation and anion exchange membranes of 80 cm2 effective cross-sectional area is used to study the desalination of brackish water having total dissolved solids (TDS) of 6000 - 10250 ppm. For brackish water containing TDS of 12000 - 27170 ppm, two ED StaCkS and for TDS of 27100 - 36000 ppm, three ED stacks containing different cell pairs of membranes having same effective cross-sectional area are used. Parallel-cum-series flow system is employed in all the stacks. The reduction in anions like Cl-, NO3- along with total hardness and TDS have been reported. The energy requirementS and current efficiencies are also given based on the experimental data. Optimum flow rates and energy consumptions are reported for obtaining potable water having TDS of congruent-to 800 ppm from different brackish Water. The results will be useful for design and operation of different Capacity of electrodialysis plants for desalting brackish water of different salinity.