Oxidation of Aged Raw Landfill Leachate with O3 Only and O3/H2O2 and Molecular Size Distribution Analysis

摘要

The aged raw landfill leachate was taken from the equalization storage tank at Clover Bar Landfill Leachate Treatment Plant, Edmonton, Alberta, Canada. The average quality parameters of this leachate are: COD = 1,091 mg/L, BOD5 = 39 mg/L, color = 1,133 TCU, NH3-N = 455 mg N/L, alkalinity = 4,025 mg CaCO3/L and pH = 8.30. The major fraction of this leachate was large refractory organic compounds. O3 only and O3 combined with H2O2 (O3/H2O2) were applied to treat this leachate, respectively, aiming at enhancing COD and color reduction and increasing its biodegradability (I.e., the ratio of BOD5/COD). The used ozone doses were 1.2 to 12.5 g O3/L leachate for O3 only, and 1.8 to 13.8 g O3/L leachate for O3/H2O2. H2O2 dose for O3/H2O2 treatment was 0.628 g H2O2/L leachate. The volume of leachate for each treatment was 250 mL. All of the oxidation treatments with O3 only and O3/H2O2 were performed in a gas washing bottle equipped with a fine diffuser. COD, BOD5, color, NH3-N, nitrite+nitrate, and alkalinity before and after treatment were measured. Meanwhile, the molecular size distribution was analyzed by using high performance liquid chromatograph (HPLC) with gel filtration column and UV detector at 254 nm. The eluant was 10 mM NaCl solution, and flow rate 0.5 mL/min. The addition of H2O2 enhanced COD and color reduction at lower used ozone doses. After oxidation, BOD5 increased by 110% for