Kinetic modeling of the promoted and unpromoted wet oxidation of debarking evaporation concentrates

In the present study, the wet oxidation (WO) of a debarking evaporation concentrate was studied at a temperature range of 383-473 K. To improve the oxidative process, the pH level of the wastewater was in some experiments set to 13 using a sodium hydroxide solution. Additionally, in some experiments H2O2, in amounts of 0.2 g per 1 g of COD was introduced into the reaction system as a promoter. All three cases, unpromoted WO, hydrogen peroxide promoted WO and WO in alkaline media, were modeled. In order to explain the experimental data, the model by Verenich and Kallas [S. Verenich, J. Kallas, Wet oxidation of concentrated wastewaters: the kinetic modelling, in: Proceedings of the IWA 2nd International Conference on Oxidation Technologies for Water and Wastewater Treatment, Clausthal-Zellerfeld, Germany, 2000] was modified and the kinetic parameters, the activation energies and frequency factors, were estimated along with the sensitivity analysis, a study on the cross-correlation and identification of the parameters. The recast model explains the experimental data well. The addition of hydrogen peroxide reduced the activation energies of the oxidative reactions.