The Taguchi method was applied as an experimental design to determine optimum conditions for colour removal from azo dyes solutions containing remazol yellow G by electrocoagulation (EC) using iron and steel electrodes as anode and cathode, respectively. An orthogonal array (OA9) experimental design that allows to investigation the simultaneous variations of four
parameters (initial remazol yellow G concentration, initial pH of the solution, time of electrolysis and current density) which have three levels was employed to evaluate the effects of experimental parameters. Performance measure analysis was followed by performing a variance analysis, in order to determine the optimum levels and relative magnitude of the effect of parameters. The desired characteristic for response has been elected as maximum
decolourization. Therefore, Taguchi’s ‘the larger the better’ performance formula was used. The optimum conditions were found to be initial remazol yellow G concentration, 100 mg/l, initial pH of the solution 9, time of electrolysis, 25 min, and current density, 1mAcm-2.