Aerobic biological treatment of black table olive washing wastewaters: effect of an ozonation stage

The present work is a study of oxidative degradation of the organic matter present in the washing waters from the black table olive industry. Pollutan t organic matter reduction was studied by an aerobic biological process and by the combination of two successive steps: ozonation pretreatment followe d by aerobic biological degradation. In the single aerobic biological proce ss, the evolution of biomass and organic matter contents was followed durin g each experiment. Contaminant removal was followed by means of global para meters directly related to the concentration of organic compounds in those effluents: chemical oxygen demand (COD) and total phenolic content (TP). A kinetic study was performed using the Contois model, which applied to the e xperimental data, provides the specific kinetic parameters of this model: 4 .81 x 10(-2) h(-1) for the kinetic substrate removal rate constant, 0.279 g VSS g COD-1 for the cellular yield coefficient and 1.92 x 10(-2) h(-1) for the kinetic constant for endogenous metabolism. In the combined process, a n ozonation pretreatment is conducted with experiments where an important r eduction in the phenolic compounds is achieved. The kinetic parameters of t he following aerobic degradation stage are also evaluated, being 5.42 x 10( -2) h(-1) for the kinetic substrate removal rate constant, 0.280 g VSS g CO D-1 for the cellular yield coefficient and 9.1 x 10(-3) h(-1) for the kinet ic constant for the endogenous metabolism. (C) 2000 Elsevier Science Ltd. A ll rights reserved.