Modeling of electro-oxidation process in saline wastewater treatment

Introduction : Biological treatment of wastewater containing high dissolved solids, because of the high concentration of salt, is not possible. A method for treating this type of wastewater is electro-oxidation process. The aim of this study was application of response surface methodology to optimize the saline wastewater treatment using electro-oxidation process. Methods : This experimental study was conducted in a pilot scale. The samples were prepared synthetically at the required level of saline wastewater.The independent variables were reaction time, pH, electrolyte concentration, and cell voltage. The process performance was evaluated based on COD and TOC removal efficiencies. The determination of the number of experiments, statistical analysis and modeling of laboratory data, and optimization of COD and TOC removal were performed using the central composite design and surface response method. Results : The results showed that the removal efficiencies of COD and TOC at the optimum conditions of pH=8, reaction time= 34 min, salt concentration= 23.5 gr/l, and voltage= 7 V were 88.48% and 69% respectively. In these conditions, the desirability of the model was 1. Conclusion : Electro-oxidation was an effective process for COD and TOC removal, but not enough to produce effluents which meet the environmental standards. Therefore, this process is proposed for pretreatment of saline waste water. In addition, central composite design and response surface methodology were appropriate to optimize the variables affecting COD and TOC removal process using electro-oxidation.