This paper investigated the performance of the electrochemical treatment technique in removing chloride from saline wastewater (brine) with the critical objective of purifying the wastewater, evaluated the efficacies of selected mathematical models and particular attention to selected polynomial regression models as a follow-up to previous studies. The saline wastewaters were prepared and subjected to electrochemical treatment using developed carbon–resin (anode) and aluminium (cathode) electrodes. Electrochemical treatment of the synthesised saline wastewaters (between 10 x 103 mg/l and 40 x 103 mg/l of chloride) was conducted on a laboratory scale. The influences of selected or picked-out operational factors on the functioning or efficacy of the electrochemical purification process of the wastewater were monitored using fractional factorial experiments. Three mathematical models were formulated using Microsoft Excel Solver and evaluated statistically. The study revealed that the current, the time and the interval distance between the electrodes were significant and vital factors that impacted on the performance of the electrochemical purification treatment of brine. The factors with negative special effects on the performance of the treatment process of brine were separation distance between the electrodes, pH, the depth of the electrode, the initial and primary concentration of the chloride and the flow and discharge rate of the wastewater. The performances or efficacy of the polynomial regression models in predicting the performance of the treatment technique were with average errors of 2.99%, 2.97% and 2.94% and accuracy of 97.01%, 97.03% and 97.06% for Models A, B and C, respectively. It was concluded that the electrochemical treatment of brine with carbon-resin electrodes is efficient in removing chloride from brine and the selected models predicted the performance of the treatment technique well.