Removal of organic contaminants in paper pulp treatment effluents under Fenton and photo-Fenton conditions

The degradation of the organic content of a bleaching Kraft mill effluent (BKME) has been carried out by using Fenton reagent and irradiation providing the conditions needed for the simultaneous occurrence of Fenton and photo-Fenton reactions. The main parameters that govern the complex reactive system, i.e. light intensity, temperature, pH, Fe(II) and H2O2 initial concentrations, and O2 presence in solution have been studied. Concentrations of Fe(II) between 0 and 800 ppm, and H2O2 between 0 and 10,000 ppm were chosen. Temperatures above 25 and up to 70 °C have a beneficial effect on total organic carbon (TOC) decay rate. The presence of small amounts of O2 seems to be enough to ensure the reaction progress. The combination of Fenton and photo-Fenton reactions has been proved to be highly effective for the treatment of such a type of wastewaters, and important advantages concerning the application of this combination of reactions arise from the study.