In this study, recalcitrant total phenol (TPh) and organic matter removal were investigated at olive mill wastewater (OMW) in sequential Coagulation and Fenton system. This study focused on different operational parameters such as pH, H2O2, and Fe2+ dosages, and [Fe2+]/[H2O2] ratios. The optimum conditions were determined as; pH = 3; [Fe2+]= 2.5 g/L; [Fe2+]/[H2O2] = 2.5. A higher treatment efficiency was achieved at sequential Coagulation and Fenton system (COD, 65.5%) and TPh, 87.2%), compared to coagulation process (COD, 51.4%; total organic carbon (TOC), 38.6% and total nitrogen (TN) 52.1%). This study demonstrated that the Coagulation and Fenton process has a potential for efficient removal of phenolic pollutants from wastewater. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.