Hydrogen Peroxide And Activated Carbon Catalytic Oxidation Degradation Of The Refractory Organics In Landfill Leachate

With the growing of the population and rapidly developing of industry andcommerce, the creation of municipal solid waste of China is increasing every day.There are a large number of highly-concentrated poisinous chemicals in landfillleachate, which is very difficult to dispose. Landfill leachate can spread into ourenvironment by all means, and then, it is harmful to the health of people directly orindirectly. Recently，the main method of treating the landfill leachate is biologicalmethod. However，because of the exsitence of hardly-biodegraded organic matter, suchas humic avid (HA), fulvic acid (FA), landfill leachate can not be completely degradedby biological treatment. In this work, the catalytic wet air oxidation of organicpollutant was studied, with activated carbon (AC) or activated carbon treated by nitricacid (ACNA) as the catalyst, hydrogen peroxide (H2O2) as the oxidizer and HA as themodel pollutant.Firstly, a new H2O2/ACNA catalytic wet oxidation system was developed for HAdegradation. The effect of temperature, time, oxegen pressure, initial PH and useamount of ACNA and H2O2on the degradation of humic avid were studiedsystematically. The area and pore diameter of original and disposaled ACNA wereComparied and analyed, and the reacting mechanism of HA degraded as H2O2/ACNAcatalytic wet oxidation system was studied primarily. The results show that under theoptimum conditions, HA was degraded completely,55%COD was removed, and thebiodegradability ration was increased from0.04to0.68after degradation; The BETsurface area of ACNA was reduced from823m2/g to703m2/g, and t-plot pore diameterwas reduced from0.14cm3/g to0.09cm3/g after degradation; ACNA exhibited goodstability in the catalytic wet oxidation of HA: when ACNA was used for seven times,46.5%COD of HA solution was removed. If H2O2/ACNA catalytic wet oxidationsystem was used for degradation of landfill leachate， it was found that thebiodegradability ratio of landfill leachate was increased from0.01to0.62. SoH2O2/ACNA catalytic wet oxidation system provides a promising pretreatmentapproach for biotreatment of landfill leachate.Then a new H2O2-H2O2/ACNA catalytic wet oxidation system was developed forHA degradation. The effect of various reaction conditions, such as temperature, time,the original pH of HA solution, use amount of AC and H2O2, on the degradation of HAwere investigated. Under the optimum condition, HA was almost degraded completely; the index of the biodegradability of BOD5/COD ratio was increased from0.05to0.96and68.2%COD was removed. If H2O2-H2O2/ACNA catalytic wet oxidationsystem was used for treatment of landfill leachate,57.4%COD was removed and thebiodegradability ratio was increased from0.01to0.5. This illustrates that H2O2-H2O2/ACNA catalytic wet oxidation system can be a perfect preprocedure, or even a mainstep to treat landfill leachate.