The effluent from dye manufacturing plant is generally recalcitrant to be decolourized visibly because of versatile composition resulting environmental problem. Hence, the UV/H2O2 process conducted using the recirculated batch reactor system with four annular UV lamps was proposed to treat the dye plant effluent in this work, while identifying the effects of hydrogen peroxide dosage, UV power input and wastewater strength on the decolouration and COD removal. From the experimental results, substantial decolouration and COD removal was increased significantly by supplementing hydrogen peroxide dosage, UV power input. Moreover, the pseudo-first order model was developed to describe the decolouration behaviour that the kinetic rates were calculated by linear regression obtaining the decolouration rate constant of 0.0993 min s(-1) while 72.0 W l(-1) of UV power and 116.35 mM of H2O2 dosage for 10% diluted plant wastewater with PtCo colour of 4550 units and COD of 1065 mg l(-1). Ultimately, the proposed recirculated four-lamp annular UV/H2O2 reactor conducted profitably to not only decolourize but also mineralize the dye plant effluent at the same time. (c) 2006 Elsevier B.V. All rights reserved.