New ironcopper based solids prepared by coprecipitation had their efficiency in the heterogeneous Fenton process investigated regarding organic charge removal and biodegradability enhancement. Different molar proportions between the two metals were used to assess the best one. Chemical oxygen demand (COD), total phenolic content (TPh), and biochemical oxygen demand in 5 days (BOD5) were the parameters used for the evaluation. Two solutions simulated olive mill wastewaters: one comprising six phenolic acids and another containing one extra acid. The efficiency of each catalyst was compared when facing both mixtures, and the one containing more phenolic acids was further decomposed, maybe due to a cooxidation synergistic effect related with the presence of more radicals. All solids proved to be fit for the reaction, and the FeCuO 50/50 catalyst showed the best overall results regarding organic charge removals.