Techno-economical evaluation of nitrate removal using continuous flow electro-coagulation process: optimization by Taguchi model

This study aims to investigate the effect of the main parameters on the performance of a continuous flow electro-coagulation (EC) process for nitrate removal efficiency and its operating costs. For this purpose, the Taguchi experimental design with orthogonal array L27 (3¹³) was applied to analyze the effects of selected parameters, namely initial nitrate concentration, inlet flow rate, current density and initial pH. According to the analysis of variance results, the inlet flow rate and the current density were recognized to be the most effective factors playing a pivotal role in nitrate removal efficiency by using an EC process. The optimum conditions of initial nitrate concentration, inlet flow rate, current density and initial pH were found to be 100 mg/L, 50 mL/min, 80 A/m² and 8, respectively. As a result, the observed nitrate removal efficiency under these conditions was 61.70%. In addition, operating costs were evaluated as 1.278 US$/g NO₃-removed. Finally, a high correlation was observed between the experimental and predicted results indicating an appropriate accuracy of the Taguchi model for nitrate removal efficiency and its operating costs in an EC system.