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 storagerntank at Clover Bar Landfill Leachate Treatment Plant, Edmonton,rnAlberta, Canada. The average quality parameters of this leachate are:rnCOD = 1,091 mg/L, BOD5 = 39 mg/L, color = 1,133 TCU, NH3-N =rn455 mg N/L, alkalinity = 4,025 mg CaCO3/L and pH = 8.30. The majorrnfraction of this leachate was large refractory organic compounds. O3rnonly and O3 combined with H2O2 (O3/H2O2) were applied to treat thisrnleachate, respectively, aiming at enhancing COD and color reductionrnand increasing its biodegradability (I.e., the ratio of BOD5/COD). Thernused ozone doses were 1.2 to 12.5 g O3/L leachate for O3 only, and 1.8rnto 13.8 g O3/L leachate for O3/H2O2. H2O2 dose for O3/H2O2 treatmentrnwas 0.628 g H2O2/L leachate. The volume of leachate for eachrntreatment was 250 mL. All of the oxidation treatments with O3 onlyrnand O3/H2O2 were performed in a gas washing bottle equipped with arnfine diffuser. COD, BOD5, color, NH3-N, nitrite+nitrate, and alkalinityrnbefore and after treatment were measured. Meanwhile, the molecularrnsize distribution was analyzed by using high performance liquidrnchromatograph (HPLC) with gel filtration column and UV detector atrn254 nm. The eluant was 10 mM NaCl solution, and flow rate 0.5rnmL/min. The addition of H2O2 enhanced COD and color reduction atrnlower used ozone doses. After oxidation, BOD5 increased by 110% for