Preliminary Catalytic Wet Air Oxidation (CWAO) tests were conducted (140°-160°C, 2-9 bar of oxygen partial pressure, at space time of 0.12 hr) for phenol, o-cresol, 2-chlorophenol and sodium dodecylbenzenesulfonate (DBS), often present in diverse industrial wastewater. All the experiments were done in a fixed bed reactor, operating in trickle flow regime and using activated carbon as catalyst. These tests permitted the determination of the biodegradability of the CWAO effluents over an activated sludge. These tests permitted the determination of the biodegradability of the CWAO effluents over an activated sludge. Taking into account these results, it was possible to establish whether or not the CWAO effluents were suitable for a conventional activated sludge plant inoculated with non-adapted culture. This is an abstract of a paper presented at the 7th World Congress of Chemical Engineering (Glasgow, Scotland 7/10-14/2005).