Catalytic wet air oxidation of phenolic wastewaters

Treatment of high concentration chemical wastewater containing phenol and/or phenolic compounds by catalytic wet air oxidation (WAO) is studied. Experimental results indicate that over 99% w/w removal of phenol or phenolic compounds can be efficiently achieved by the catalytic WAO process utilizing hydrogen peroxide as homogeneous oxidant. It is observed that the catalytic WAO process achieves high efficiency of phenol or phenolic compound oxidation at lower operating temperature (150 degrees C or less) and pressure (0.5 MPa) than those of comparable conventional WAO processes. The experimental data also show that the oxidation reaction can be represented by a first-order, two-stage kinetics in terms of the component or COD concentration. The second-stage oxidation was observed to be slower than the first-stage. The activation energies obtained for oxidation of phenol and phenolic coumpounds reflect the speed of these two stage reactions.