The iron sludge generated from electrocoagulation process was employed for the degradation of phenol through photo-Fenton process instead of iron salts. The morphology, functional groups and chemical composition of the iron sludge were investigated using scanning electron microscopy, Fourier infrared spectroscopy, and energy-dispersive X-ray spectroscopy. The effects of iron dose, H2O2 concentration, reaction time and initial concentration of phenol onto photo-Fenton process performance were studied. The degradation efficiency of phenol reached 100% in the case of light compared to 68.6% in the case of the dark reaction at pH of 3, iron dose of 150 mg/L and H2O2 concentration of 1.5 g/L. The degradation efficiencies of phenol were 100%, 71.3 and 51% at initial phenol concentrations of 50 mg/L, 100 mg/L and 150 mg/L, respectively. The expected cost for the treatment of one cubic meter of the contaminated wastewater was estimated to be 0.6224 $/m3.