A novel combined electrochemical system for hardness removal

• A novel concept of electrochemical system was established for hardness removal.
• The total hardness removal was increased for the large improvement of floc removal.
• The new system had lower operating cost than electrochemical precipitation process.
• The new system produced less sludge than electrocoagulation process.

A novel electrochemical system was proposed to remove hardness species, by combining the conventional electrocoagulation process and electrochemical precipitation process. The results showed that the new system had excellent synergistic effects. The little amount of Al floc produced in electrocoagulation cell enhanced the hardness removed by floc in electrochemical precipitation cell by 224.65% which increased the total hardness removal in the electrochemical precipitation cell by 69.16%. Meanwhile, the amount of deposit on the cathode surface in electrochemical precipitation cell was decreased by 22.79%, which would delay the cathode inactivation in practical application. The operating cost of the new combined electrochemical system was reduced by 53.09% than that of the conventional electrochemical precipitation process. And the production of sludge was nearly three times decreased in the new system than that in the conventional electrocoagulation process, for the lower current density. Therefore, this new proposed system is a beneficial technology for hardness reduction, which can overcome the drawbacks of the two conventional processes.

The mechanism of the novel combined electrochemical system for hardness removal.Figure optionsDownload as PowerPoint slide