Supercritical Water Oxidation of Olive Oil Mill Wastewater

The supercritical wet air oxidation of olive oil mill wastewater has been carried out at 25.0 MPa of total pressure and temperatures in the range 380−500 °C. The process is well described by simple first-order kinetics with no dependence on the oxygen concentration when it is in excess. The apparent activation energy of the reaction has been found to have a value of 32.7 kJ mol-1 for chemical oxygen demand (COD) removal. Similar values have been calculated for other global parameters analyzed (total carbon, total organic carbon, etc.). The use of free-radical promoters enhances the efficiency of the treatment by lowering the activation energy of the process up to a value of 27.5 kJ mol-1 for COD elimination. Both promoted and nonpromoted oxidations mainly occur through total mineralization.