| Treatment of landfill leachate was a challenge for domestic and overseas researchers. In this experiment, the landfill leachate were fetched from Xinxiang waste treatment plant, and stored in refrigerator at 4℃, Its Chemical Oxygen Demand(COD) were about 2600 to 3100 mg/L. The leachate were diluted with tap water to its COD about 400 to 500 mg/L,and its Biochemical Oxygen Demand 5(BOD5) about 25 to 30 mg/L, p H at 8.53 to 8.72. The diluted leachate were treated with Biological activated carbon(BAC) at first, and then pre-oxidated with ozone, Finally, made the diluted leachate with biotreatment. Research the effluent by BAC treated in-depth, Including the demand of ozone pre-oxidation, water quality of BAC treated leachate, demand of biotreatment, water quality of ozone pre-oxidation and biotreatment, and addition of different catalysts in the process of ozone pre-oxidation. Catalysts taken in this experiment were CuO(in powder form,and the results were shown below:1. Pre-oxidation wtih 12 L diluted leachate for six different times. In the process combined with ozone and biology, after the pre-oxidation, there were six ozone-Sequencing Batch Reactor(O3-SBR) connected for parallel comparisons, to compare the relationship between COD removal rate and ozone dosage. The results shown that if ozone dosage were higher than 0.2 mgO3/mg COD,COD removal rate were started to increasing slowly,Enlargement of ozone dosage have insignificant changes to the utilization efficiency.Biotreatment were acted for determine the different ozone dosage, And the results indicated that at the inflexion point the best synergistic effect could be achieved. Experiment results of carbon dioxide yield manifested that organic matters could be biodegradated best if the optimum ozone dosage were chosen. The results above demonstrated that ozone pre-oxidation changed the biodegradability of leachate, and solved the problem of degradation of refractory organic matters.2. Analysis of COD, BOD5/COD, Excitation Emission Fluorescence Matrix(EEFM), and UV254(Ultraviolet Absorption at 254 nm) of diluted leachate with ozone pre-oxidation shown that ozone pre-oxidation changed the water quality significant. For instance, COD were going down, which means that organic matters which was easily degradable were wiped out. Biodegradable were enhanced because the data of BOD5/COD were increasing. Analysis of EEFM shown that fluorescence intensity of the major fluorescence peak were decreased, which means that structures of organic matters in leachate were changed. Organic matters in the structure of unsaturated state were broken by ozone, which lead the UV254 to decreased.3. Usage of diluted leachate in experiment were 400 mL, 3 L, 4 L, 5 L, 12 L. And ozone pre-oxidated with the same gas flow but different dosage. The results indicated that after pre-oxidation, COD removal rate of landfill leachate were going stable at the ozone dosage were about 0.2 mgO3/mgCOD, but the experiment with 400 mL leachate were not follow this rule, the reason may because of the ozone utilization could not have a high level with a massive ozone dosage at tiny water volume. COD removal rate could not have a continuous enhancement with the lengthen of time of ozone pre-oxidation. The results above could prove that ozone dosage was the major factor of COD removal rate in the experiment of ozone pre-oxidation leachate treatment.4. CuO(in powder form)as catalysts in this experiment, Comparison of COD removal rate of ozone pre-oxidation, ozone pre-oxidation with catalyst added, and BAC absorption were taken. The consequence demonstrated that with the addition of CuO stirred could achieved the best result, and the inflexion point were anticipated. EEFM shown that single use of ozone pre-oxidation and with catalyst added can made the leachate have a big change in water quality. Degradablity of refractory organics with ozone were enhanced. Experiment results proved that study on the inflexion point of COD removal rate have great significance, addition of catalyst could shorten the demand of time of ozone pre-oxidation, which could save the cost.5. Through the analysis of CuO catalytic reaction kinetics, it is concluded that the reaction rate constant and the relationship between the catalyst dosage for: K = 0.0316 [CuO] 0.058, R2 = 0.9817. |
PDF Full Text Request