Super critical water oxidation: A novel technique for waste water treatment

Many aqueous waste products cannot be destroyed by biological treatment and several industrial waste water containing highly toxic substances are difficult to dispose off. New processes have to be developed for the treatment of such effluents. Super critical water oxidation (SCWO) is one of such newly developed process, in which toxic organic chemicals present in waste water or sludge can be completely destroyed or converted into less harmful products. SCWO is operating at pressure and temperature above critical data for water (Pc=22.1 MPa & Tc = 374 0C). Under these conditions the fluid has a density between that of water vapor and liquid at standard conditions, and exhibits high gas-like diffusion rates along with high liquid-like collision rates. In addition, solubility behavior is reversed. The reversed solubility also causes salts to precipitate out of solution, meaning they can be treated using conventional methods for solid-waste residuals. These review papers provide a brief overview of chemistry, operational characterisics and information about different reactors of SCWO technique.