Electrochemical treatment of synthetic solution containing Acid Red 131 dye was studied by performing experiments in a batch mode of operation using aluminum electrode. The effect of various parameters, such as the pH of the solution, current density, interelectrode distance, agitation speed, solution conductivity, electrolysis time, retention time, and initial concentration of the dye in the solution, was investigated. The results were analyzed in terms of color removal efficiency (CRE) and the optimum values of the parameters were determined. The maximum CRE (98%) for a synthetic dye solution was obtained at the optimum conditions of current density of 0.0625 A cm(-2) and a pH solution of 11 for an electrolysis time of 120 min. Electrochemical treatment of industrial effluent containing Reactive Black B, Orange 3R, and Yellow GR dyes was carried out at the optimum values of the parameters and a CRE of 93.5, 92, and 91.1% was obtained for the three dyes, respectively. Experiments were performed using aluminum sulphate as the coagulant to compare the color removal efficiencies obtained by electrocoagulation and chemical coagulation. (C) 2014 American Society of Civil Engineers.