OSCAR is a technology suitable for the sludge treatment, based on the Wet Oxidation (W.O.) process. It eliminates the organic compounds dissolved in the sludge, which become CO2 and H2O by means of W.O.. OSCAR does not replace the Primary nor Secondary treatment of the wastewater. OSCAR can replace the anaerobic digestion that produces Methane, whose GWP is twenty times worse that carbon dioxide. OSCAR provides huge saving in the sludge treatment. It eliminates all the microorganisms and it can provide water for irrigation. Besides, OSCAR benefits from the heat released during the oxidation, producing saturated vapor which can be used for central heating, cleaning, to generate electric power… It is a very efficient technology to be placed in a reduced space plant. It is environmental friendly. All this together: OSCAR is the best choice to eliminate the sludge in every country moreover where the legal drawbacks for the incineration and landfilling are increasing.