WET AIR OXIDATION OF TRINITROTOLUENE MANUFACTURING RED WATER

An effective use of the wet air oxidation (WAO) process at a temperature of 340-degrees-C and 0.8 MPa P(O2(25-degrees-C)) to treat diluted trinitrotoluene (TNT) red water was previously demonstrated. This study presents the results of a 1-hour WAO of red water at temperatures ranging from 200-degrees to 320-degrees-C, and P(O2) from 0.13 to 1.31 MPa, in terms of contaminant reduction and intermediate appearance. Also, comparison is made between the toxicity of the raw and the WAO-treated red water on two biological systems. Results show the WAO removal efficiency to be a function primarily of temperature and, to a lesser extent, of P(O2). Acetic acid and 1,3-dinitrobenzene (DNB) accumulated at lower temperatures. For example, total organic carbon (TOC) and chemical oxygen demand (COD) removals at 260-degrees-C and 0.62 MPa P(O2) were 77 and 91%, respectively. Acetic acid and DNB concentrations were 60 and 21 mg/L, respectively. At 320-degrees-C and 0.62 MPa, however, the acetic acid and DNB levels were 38 and 6 mg/L, respectively. The corresponding TOC and COD reductions were 94 and 99%. Organic products formed during the WAO of red water appear to be responsible for adverse effects on nitrite production rates of enriched, unacclimated Nitrosomonas, as compared with raw red water. The WAO-treated water, however, had no effect on the heterotrophic activated sludge capability in degrading glucose.