BACKGROUNDThis work explores the application of an intensified Fenton process to a sulfonation plant wastewater for its further discharge into an activated sludge plant. The application of high-temperature Fenton to this kind of wastewater has not been reported so far. Herein, it has been demonstrated to provide a better performance than other advanced oxidation processes (AOPs). RESULTSThe factorial experimental design methodology applied for describing the effect of the operating conditions, temperature, hydrogen peroxide dose and pH, demonstrated that quadratic models satisfactorily fitted the experimental results according to the analysis of variance (ANOVA). Response surface, contour plots and surface projections of the models were obtained describing the individual and crossed effects of the operating conditions on the selected responses: linear alkylbenzene sulfonate (LAS), total organic carbon (TOC) and chemical oxygen demand (COD) reduction. CONCLUSIONSWorking at 94 degrees C, 70% of the stoichiometric H2O2 dose relative to initial COD, 1h reaction time and the pH of the wastewater as received (1.7) enabled achievement of the discharge limits into the exiting activated sludge plant of the petrochemical complex where the sulfonation plant is located. (c) 2014 Society of Chemical Industry