treatment through chemical precipitation and electrodialysis
In the present work, treatment of an electroplating wastewater in a high
chromium concentration has been studied through chemical precipitation (CP)
and electrodialysis (ED). It has been found that chemical precipitation or
electrodialysis alone could not produce a qualified water to be recycled to
electroplating lines as rinsing water. Accordingly, a novel process,
combined chemical precipitation and electrodialysis (CP-ED), has been tested
on the wastewater. The experimental results have shown that the CP-ED
process greatly eliminated chromium from the wastewater, about 95% Cr (VI)
removal, leaving the cleaned water assaying 0.18mg/l Cr(VI). Also, the CP-ED
process effectively removed other ions such as Na+ and Cl that were
involved into the wastewater because of adding precipitants in the CP step.
Compared with CP treatment, CP-ED process allowed a large saving at reagent
cost and operation cost, and less environmental concerns.