Evaluation Of Landfill Leachate Quality With Microorganism Preparations And Fenton Oxidation Process

With the rapid economic development and the expansion of the urban population in China, the production of municipal solid waste increased quickly. The landfill leachate that is of complex composition generated from sanitary landfill, is a kind of harmful wastewater with high concentration of organic matter. The surrounding environment and underground water or soil will be seriously polluted if the leachate. is not treated properly and discharged arbitrarily. Therefore, control and treatment on the pollution of the landfill leachate has become a major issue in the current environmental protection field. At present, study and application of the microbial method to treat landfill leachate attracts more and more attention of people. Treating the landfill leachate by microorganism preparations can degrade the pollution components of landfill leachate to reduce the pollution to the environment. In this study, experiments were carried out to use the microorganism preparations and single flora preparation to decrease the COD, ammonia nitrogen and total phosphorus of landfill leachate, and to study the degradation mechanism.The sample from Nanjing Lishui landfill leachate was chosen as the object of study, a series simulation experiments were designed to study the effects of the microorganism preparations and single flora preparation on the treatment of landfill leachate in the laboratory. The effects of microorganism preparations and single flora preparation treatment of landfill leachate were compared, to explore the main degradation mechanism. Because the COD was still high after landfill leachate was treated by the microorganism preparations, and considering that the mature lanfill leachate was not fitted to be by following biochemical treatment, the Fenton test was used for depth treatment of landfill leachate.The results show that the microorganism preparations was efficient to treat landfill leachate, having a certain effects on the decrease of landfill leachate COD, ammonia nitrogen and total phosphorus. Inoculum quantity of the micro-organism preparations, reaction time, aeration time and pH could affect the treatment of Landfill Leachate. After experiment, the optimum inoculation was1/2000, the optimal reaction time was60h-72h, the optimum aeration time was36h-48h, and the optimum pH was8. The maximum decrease rate of landfill leachate COD could reach31.1%, the maximum decrease rate of ammonia nitrogen could reach83%, the maximum decrease rate of total phosphorus could reach71%.The effect of the micro-organism preparations treatment of Landfill leachate was better than that of single flora preparation treatment. Lactic acid bacteria could decrease COD and ammonia nitrogen of landfill leachate at30%and35.7%, respectively; Actinomycetes could decrease COD of landfill leachate at58.5%, and ammonia nitrogen at38%, similar to lactic acid bacteria treatment. After treated by compound microorganism preparation the oxidation treatment of Fenton could be applied for subsequent treatment of landfill leachate. The effect of Fenton treatment of Landfill Leachate was significant. The best effect was got when25mL/L H2O2and4.25g/L FeSO4were added, and COD could be decreased to336mg/L, with the maximum reduction rate being at77.6%.The degradation Mechanism of microorganism preparations treatment of landfill leachate was that the each single flora in the microorganism preparations could degrade the components in landfill leachate, forming symbiosis and synergies of all flora, forming a complete and complex microbial community, effective for treatment of landfill leachate. The number of lactic acid bacteria increased from5.8×109CFU/mL to1.2×1010CFU/mL, explaining that adding the compound microbiological preparation in the landfill leachate could change the microbial community structure in landfill leachate, and was better for the treatment of landfill leachate.