The study on the wet air oxidation of highly concentrated emulsified wastewater and its kinetics

The highly concentrated emulsified wastewater containing non-ionic surfactant is hardly biodegradable, and few cost-effective techniques of treatment are available. In this paper a systematic study on its wet air oxidation (WAO) and the related decrease efficiency of COD, TOC, influencing factors, characteristics of the kinetics was performed in a 2-1 high-pressure batch autoclave. The result indicated that the application of WAO had a good performance in the treatment of emulsified wastewater and the operation conditions such as temperature, partial pressure of oxygen, concentration of input wastewater have influence on the oxidation efficiency to different extent. And the temperature is the key influential factor: COD of the wastewater (initial COD: 48 000 mg/l) was reduced by 86.4% after 2 h oxidation at 220 degreesC, with the supply of oxygen 1.25 times more than its theoretical value. A general kinetic model can be used to explain the WAO process with sufficient oxygen supply, and an exponential model was developed. (C) 2002 Elsevier Science B.V. All rights reserved.