The electrochemical oxidation of organic pollutants is a promising process for substances which are recalcitrant to biological degradation. The anodic oxidation of coumaric acid, which is a biorefractory organic pollutant of olive oil manufacturing waste waters, was evaluated on a Pt-Ti electrode. The operating test conditions were compatible with direct discharge of the after-treatment effluent in natural water basins or rivers as regards the electrolyte salt content (Na2SO4 = 0.02 N). The affect of the applied current density, pH, temperature, initial coumaric acid concentration and of the type of DC feeder (a galvanostat or a simple current rectifier) over the oxidation rate was assessed through a series of batch runs performed in a pilot plant apparatus. Beyond direct oxidation at the Pt-electrode surface, bulk oxidation with hydrogen peroxide, generated through a persulfate-formation/hydrolysis route, was found to be a crucial step in coumaric acid degradation to more biodegradable non-aromatic products. Small quantities of Fe ions were helpful in accelerating the oxidation process. An analysis of the rather complex reaction schemes governing the process is proposed. (C) 2000 Elsevier Science Ltd. All rights reserved.