Treatment of black-olive wastewaters by ozonation and aerobic biological degradation

The degradation of the organic pollutants present in black-olive wastewater was carried out by ozonation, aerobic biological degradation, and the comb ination of two successive steps: an aerobic biological process followed by an ozonation. Contaminant removal was followed by means of global parameter s directly related to the concentration of organic compounds in those efflu ents: chemical oxygen demand and total aromatic and phenolic contents. In t he ozonation, an approximate kinetic study was performed to determine the a pparent kinetic constants for the COD reduction, k(COD), and for the total aromatic reduction, k(A) In the aerobic biological degradation, the kinetic study was performed using the Monod model applied to the experimental data . In the combined process, a higher overall reduction in COD and aromatic c ontent was achieved by the successive stages, and there was improved remova l of the organic material during the second treatment. This enhancement was reflected in an increase in the apparent kinetic constants in the ozonatio n of the wastewater that had previously been treated aerobically, relative to the Values obtained for the kinetic parameters in the single process exp eriment which were carried out under the same operating conditions. (C) 200 0 Elsevier Science Ltd. All rights reserved