ABSTRACT
The integration of a chemical treatment system, specifically wet air oxidation (WAO) processes, with the conventional biological treatment has greatly enhanced the performance of the wastewater treatment system by converting recalcitrant compounds into more readily biodegradable products. WAO, also known as liquid phase oxidation, is an oxidation process using pure oxygen gas or air to oxidize organic or inorganic compounds at high temperatures and pressures. The reaction mechanisms of WAO processes are normally elucidated using either phenol or carboxylic acids. The introduction of a catalyst in WAO can significantly reduce the energy consumption and temperature, yet can achieve high oxidation rates. Two types of Catalytic WAO Processes (CWAO) technologies were developed over the decades, namely heterogeneous and homogeneous CWAO. Conventional biological treatment for pharmaceutical wastewater may not be applicable to pharmaceutical wastewater that contains high amount of COD. This constraint makes WAO process an attractive option as a pretreatment to enhance the biodegradability of pharmaceutical wastewater.
