Ozonation of black-table-olive industrial wastewaters: Effect of an aerobic biological pretreatment

Abstract

The present work is a study of oxidative degradation of the organic matter present in the washing waters from the black-table-olive industry. This oxidation is performed by an ozonation process, by an aerobic biological degradation process, and by another ozonation of biologically pretreated washing waters. In the ozonation process, a second-order kinetic reaction with respect to ozone and COD or aromaticity has been deduced. The kinetic rate constants were correlated as a function of temperature by Arrhenius-type equations. In the aerobic biological treatment, a kinetic study was performed using the Contois model, giving a value of 4.8 10-2h-1 for the kinetic bioreaction constant. Likewise, a cell yield coefficient of 0.30 g VSSg COD-1 and a kinetic constant for the endogenous metabolisme of 1.2 10-2h-1 were deduced. Finally, in the ozonation of biologically pretreated wash-waters, the deduced kinetic rate constants for COD and aromaticity were, respectively, 4.5 and 2.4 times higher that those corresponding to the ozonation of wash-waters without biological pretreatment. (C) 2000 Society of Chemical Industry.