This study compares the performance of Fenton and electro-Fenton processes for phenol degradation. The effects of operational parameters such as initial pH, current density, concentration of phenol and hydrogen peroxide on phenol removal was investigated in electro-Fenton process. The degradation and mineralization efficiency increased with an increase in hydrogen peroxide concentration and current density and decreased with an increase in initial phenol concentration and initial pH. It was found that optimum pH, current density and H2O2 concentration were 3.0, 1 mA/cm(2) and 500 mg/L, respectively. Under the optimized conditions, the phenol and chemical oxygen demand (COD) removal efficiency reached 93.32% and 87.5%, respectively. In conventional-Fenton process, the effect of hydrogen peroxide and Fe2+ concentrations on the degradation and mineralization of phenol removal were investigated. The results indicated that the conventional-Fenton process only yields 59% mineralization. An estimation of the operating costs of the processes investigated showed that electro-Fenton was the more economical system to treat the phenol containing wastewater. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.