Application Of Photocatalytic And Photoelectrocatalytic Oxidation For The Treatment Of Landfill Leachate

To improve the effluent quality and reduce pollutant concentration in landfill leachate, the photocatalytic oxidation and photoelectrocatalytic oxidation were carried out in lab-scale to treat the effluent,respectively ,which was discharged from aerobic and anaerobic biofilm treatment processes. Mechanism of degradation was discussed as well as various parameters.In the photocatalytic and photoelectrocatalytic experiments, the removal percentages of COD and UV254 were both went up to a stable number as a result of increasing catalyzer concentration and reaction time. The lower the initial COD concentration of landfill leachate was, the higher the removal percentages of COD were. However, neither too low nor too high initial COD concentration of landfill leachate was in favor of the removal percentages of UV254. The COD and UV254 removal efficiency were higher when the pH values were neutral and weakly acidic, respectively. The photoelectrocatalytic experiments also shown that the COD removal was more efficiency when the electrical bias applied was about 0.3V. However, to reach the efficiency UV254 removal, the optimal electrical bias applied was variable.The photocatalytic and photoelectrocatalytic orthogonal tests shown that the order of factors effecting on COD removal in decreasing sequence were reaction time, initial COD concentration of landfill leachate, catalyzer concentration and electrical bias applied, initial COD concentration of landfill leachate, catalyzer concentration, reaction time, respectively. Also, the order of factors effecting on UV254 removal in decreasing sequence were initial COD concentration of landfill leachate, reaction time, catalyzer concentration and initial COD concentration of landfill leachate, catalyzer concentration, reaction time, electrical bias applied, respectively.The reagent of H2O2 and Fenton can both promote the reaction of photocatalytic oxidation and photoelectrocatalytic oxidation. When added H2O2 reagent, the removal percentages of TOC and UV254 were around 45% and over 80%, while added Fenton reagent, the removal percentages of TOC and UV254 were around 60% and over 85%.In the treatment of fulvic acid in the landfill leachate by photoelectrocatalytic oxidation, the results shown that the remove percentages of UV254 and TOC reached maximum while the electrical bias applied was 1.2V. And also, the removal percentages of UV254 and TOC were over 77% and 45% after reacting two hours.