Abstract: Catalytic Wet Air Oxidation(CWAO) was used for the decomposition of ammonia(NH₃-N) from the landfill leachates in the presence of Co/Bi catalyst and the relative content of nitrogenous organic compounds in the landfill leachates was also measured by GC-MS. The results show that the decomposition ability of NH₃-N by CWAO gradually increased with increasing reaction temperature. The kinetic decomposition of NH₃-N at temperatures 220, 240, 260 and 280 ℃ was well described with the first-order kinetics model(r>0.93, n=6). During the overall process of temperature rising(20—300 ℃), the concentration of NH₃-N increased in the first stage and then decreased in the second stage, which culminated at 220 ℃. Further investigations by GC-MS indicated that during the first stage, some nitrogenous organic compounds in the landfill leachates were degraded into NH₃-N by CWAO, and then NH₃-N was degraded by CWAO during the second stage, which presented the advantage of simultaneous removal of both NH₃-N and organic compounds by CWAO. One of the nitrogen-organic compounds, 2-mercaptobenzothiazole, in the landfill leachates was selected to verify the degradation of the nitrogen-organic compounds.

Key words: Catalytic wet air oxidation, Landfill leachates, Ammonia-nitrogen, Co/Bi