Use of a combined electrocoagulation-ozone process as a pre-treatment for industrial wastewater

This work evaluates the improvement in effectiveness in the treatment of actual industrial wastewater when the existing biological treatment is enhanced with electrocoagulation and ozonation pre-treatments. The wastewater used in this study came from an industrial complex of 140 large factories. The combined electrocoagulation-ozonation was found to be a suitable pre-treatment for the traditional biological processes, and it was also found to be useful as a complete treatment for the discharge of industrial effluents into municipal sewers. It was able to decrease the color and the turbidity of the wastewater by more than 90% and the COD by more than 60%. The electrocoagulation results are explained by sweep coagulation as the primary coagulation mechanism. Ozonation was able to diminish the pollutant load of the wastewater, but the results obtained when this treatment was applied alone were less than those obtained by electrocoagulation. The biological treatment alone was not effective for the treatment of the raw effluents of these factories, but in combination with the electrocoagulation-ozonation process it led to a high-quality effluent.