The landfill leachate belongs to typical high concentration and organic pollutant wastewater. In this study, Landfill leachate was treated with Catalytic Wet Air Oxidation (CWAO) method. The monitoring indicators consist of CODCr, absorbance, pH and chroma. The results show that the activity of the catalysts arrange from high to low: Co (NO3)2, Cu (NO3)2, Fe (NO3)3, CuSO4, Fe2(SO4)3, Mn (NO3)2, FeSO4, Zn (NO3)2, Bi (NO3)3, Zr (NO3)2, Ni (NO3)2; For the same kind of metal, the catalytic activity of nitrates is higher than that of sulfates; Relative to the distribution of catalyst, the activity of Co (NO3)2 is the strongest. With the optimized catalyst Co (NO3)2 , the landfill leachate has been treated. With the extension of reaction time, the effluent CODCr, absorbance and chroma reduced, but the wastewater biodegradability indicator B/C improved. At the reaction time of 90 min, the CODCr of landfill leachate reduced to 7176 mg/L, and the absorbance and the chroma reduced to 9.1 and 1600 times, respectively. The above results show that the activity of catalyst Co (NO3)2 is high, and the biochemical indicators B/C of wastewater is higher than the critical value of 0.3. Therefore, the treated wastewater shows the good biodegradability, and the chosen catalyst of Co (NO3)2 presents the high activity.
