DECOMPOSITION OF AROMATIC NITRO COMPOUND IN WASTE WATER

PROBLEM TO BE SOLVED: To decompose different aromatic nitro compounds in waste water as many as possible in a single process when decomposing nitro compounds in the waste water and a mixture of more than two these compounds, by using at least one aromatic nitro compound not having a hydroxyl group in its aromatic ring. SOLUTION: Waste water is thermally decomposed in a pressure vessel under such a condition that temperature is 150-350 deg.C, favorably 250-320 deg.C, pressure is 10-300 bars, favorably 40-250 bars, and the pH of the waste water is 7-14, favorably 10-13. The temperature of the waste water is adjusted so that nitroaromatic compounds with low solubility do not form an organic phase. The amount of the nitro compound with low solubility in water is adjusted according to the temperature of the waste water preferably of 40-80 deg.C. Thereby, the aromatic nitro compounds having no hydroxyl group and the nitro hydroxy aromatic compounds in the waste water can be decomposed at the same time in a single process.