Continuous Treatment Of TNT Red Water By Supercritical Water Decomposition And Oxidation

The composition of TNT red water is complicated, which has the characteristics of high concentrations of pollutants and high biological toxicity. In addition, most of the pollutant molecules contain benzene ring so that makes it difficult to be treated directly with traditional treatment methods. If TNT red water is directly discharged into the environment, it will not only pollute soil and water, but also bring health and life threat to human. In this investigation, TNT red water is treated continuously by supercritical water decomposition and oxidation, and the effect of reaction temperature, pressure and residence time on the removal rate of organics is explored.The results show that the continuous supercritical decomposition method is effective for removal of organics of TNT red water. CODCr removal rate can reach 93.05%. Single factor study results show that temperature has the maximum effect on the removal rate of CODCr, the effect of time is the middle, and the effect of pressure is the minimum. The CODCr and chromaticity of the effluent water increases with the temperature increasing from T1 to T2, but decreases with the temperature increasing from T2 to T4. The CODCr and chromaticity of the effluent water decreases with increasing the residence time. At lower temperature, the CODCr and chromaticity of the effluent water is more sensitive to the change of temperature than the higher temperature. The effect of the pressure on the effluent water CODCr is very small. The effluent water is alkaline. The supercritical water decomposition involves some types of reactions like oxidation and decomposition.After supercritical water decomposition and oxidation, most organics of TNT red water is removed. The remaining organics of the effluent water may be carboxylic acid salts and so on. The results show that the CODCr and chromaticity of the effluent water decreases with increasing the oxidation time and decreases with increasing temperate. At lower temperature, the CODCr and chromaticity is more sensitive to the change of temperature than the higher temperature. The removal rate of chromaticity reaches more than 99%. Under the decomposition conditions of T3 and 24 MPa and the oxidation conditions of T4 o and the residence time of 11 min, the CODCr of the effluent water can be reduced to 81.4mg·L-1, which can satisfy CODCr emission requirements of the first class discharge standard of GB14470-2002. The effluent water is acid.