Fenton process was applied to the pretreatment of wastewater from dry-spun acrylic fiber (DAF) manufacturing. The effects of operating parameters including the Fenton reagent dosage, the initial pH value, and the reaction time on the treatment efficiencies of the Fenton oxidation process were observed. About 47.0% of the chemical oxygen demand (COD) removal efficiency was reached under the optimum conditions: hydrogen peroxide of 90.0 mM, ferrous ions of 20.0 mM, pH value of 3.0, and reaction time of 120 min. The COD degradation of the Fenton process followed the pseudo first-order reaction kinetics, and the apparent activation energy E, was determined to be 41.6 kJ mol(-1). After the Fenton pretreatment under the optimum reaction conditions, the BOD5/COD ratio of wastewater increased from 0.32 to 0.69, which was suitable for further biological treatment. The improvement of biodegradability was attributed to the removals of aromatics and some other bio-refractory compounds from the wastewater, as confirmed by gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FIR) and fluorescence excitation-emission matrix (EEM) spectroscopy analyses. Fenton process was proven to be an effective method for the pretreatment of DAF manufacturing wastewater prior to biological treatment. (C) 2012 Elsevier B.V. All rights reserved.