The chemical oxidation of the wastewaters generated during storage of table olives in NaCl brines, prior to their manufacturing process, was studied. Ozone alone produced COD removals in the range 14-23%, and a higher average removal of 73% of the aromatic compounds. The additional presence of hydrogen peroxide and UV radiation increased these values to 39% for COD and 86% for aromatics. However, UV radiation alone only gave a removal of 9% for COD and 27% for aromatics, and the additional presence of 0.5 M H2O2 led to 13% for COD and 38% for aromatics, respectively. The Fenton's reagent oxidation achieved a COD removal of 24% for the higher concentrations of Fe2+ and H2O2. The most effective process was the combination O-3/UV/H2O2 with total removals of 65 and 92% for the COD and aromatics, respectively. The aerobic treatment of these effluents gave a 66% removal regardless of the initial biomass concentration used, and a rate constant of 0.19 per day was obtained for the process by using the Contois model. Finally, the aerobic treatment of the wastewaters previously ozonated alone, and ozonated with UV radiation, gave increases in the COD removal and a final rate constant of 0.44 per day. The enhancements were due to the chemical oxidations, these procedures being suitable technologies as pre-treatments to subsequent biological processes for the purification of these residues. (C) 2002 Elsevier Science B.V. All rights reserved.