This work presents an innovative design and modelling of a supercritical water oxidation (SCWO) reactor capable of operating effectively under industrial requirements. The cool wall reactor has a reaction chamber where the reaction occurs and a pressure vessel, which support pressure but not oxidant atmosphere. The pressurised feed-stream flows down and cool the reaction chamber so reactor temperatures up to 800 degreesC are possible for pressure vessel temperatures of 400 degreesC. The reactor allows to carry out total degradation of the pollutant (over 99.9 wt.% in TOC removal) and has been design to maximise the heat recovery from the reaction effluents, and therefore, is able to operate in almost autothermal conditions with flowrates between 25 and 65 kg/h of polluted water. The proposed design has been tested in pilot scale with outstanding results to degrade organic pollutants. A mathematical model has been implemented to show the advantages of applying an indirect kinetic pathway: the results of the simulation agree with the experimental data, and show that the use of low temperatures in the reactor enhances the formation of stable reaction intermediates (acetic acid and methanol) which reduces the total removal efficiency of the reactor. Result are shown for oxidation of isopropyl alcohol (5.3-8 wt.%) and 0.5 wt.% of dimethylsulfoside (DMSO) using both air and pure oxygen as oxidant agents. (C) 2003 Elsevier B.V. All rights reserved.