Low-Cost Catalysts To Enhance Ozone Action on the Depuration of Olive Mill Wastewaters

Abstract

With the aim of selecting a low-cost catalyst to enhance ozonation on the treatment of olive mill wastewaters (OMW), volcanic rock, sepiolite, and iron shavings (zerovalent iron (ZVI)) were tested. ZVI provided the best results; thus, its behavior was explored by analyzing the impact of the key operating conditions. It was verified that the highest degradation was reached when 1 gCat/L, 20 gO3/m3, pH 3, and 20 °C were used. Catalyst stability was checked by reusing it in several feeding batch trials, and satisfactory removals were still attained after five experiments. Finally, catalytic ozonation over ZVI was tested in real OMW, and the results were very similar to those reached for the simulated solution. Moreover, a high toxicity removal was detected. It seems thus that iron shavings can successfully be applied as a catalyst-integrating waste management with wastewater treatment.