Phenol concentration was followed along the reaction time to evaluate the effect of the used AOPs on the oxidation of organic pollutants. In addition, TOC was monitored along the runs to assess the mineralization. Reaction was carried out at acidic pH = 3 because it is well known that Fenton's reaction has shown the best results at this pH value. However, at acidic pH, iron and copper are leached from the surface of slag grains. Iron species, which are leached from slag as Fe2+ and Fe3+ are known as catalysts to break down the H2O2 molecule. Moreover, copper specie Cu2+ has also been found to produce H2O2 break down to *OH radicals [15]. Thus, it can be assumed that a synergic catalysis between copper and iron species may occur in the experimental system. In this type of system, some authors demonstrated that homogeneous catalysis predominates at pH between 2 and 4.4 while heterogeneous catalysis prevails at pH between 4.4 and 7.0 [16] and [17]. Therefore, it is assumed that slag/H2O2 and slag/H2O2/UV catalytic reaction takes place predominately in homogeneous phase.