Study On The Solute Migration Discipline Of Recirculated Leachate By Li~+Tracer

Since the waste sanitary landfill had advantages of reliable in technology, simple process, convenient management, widely applicability and most thorough treatment, it has widely used. But waste sanitary landfill still has many deficiencies, especially the leachate treatment is difficult and cost is high, if it was untreated, it will produce secondary pollution on the surrounding environment water, this will cause great disadvantage. At present, domestic and foreign scholars have done a lot of research on landfill water quality changes and moisture migration discipline, but the leachate solute migration discipline in the landfill had less research, therefore, the author did experiment indoor which can simulate leachte solute migration, through analysis the factors which can affect leachte solute migration-waste density and recirculation amounts, to strengthen the understanding of the landfill pollutant removal mechanism, and referenced the solute adverction-dispersition equations in solution, established leachte solute migration hydrodynamic dispersion model, at last, the author sloved the model and verified it.The results show that:(1) After the first recirculation cycle, the changing trends with time of leachate Li+concentration and leachate flow rate had the similar law, that both showed a sharp increase, reaching the maximum value and then slowly decreased, the greater density of waste, the maximum concentration、average concentration and Li+leaching amount are smaller, but the intercept amount of Li+in the waste had the opposite trend. Contrast the first recirculation cycle value of different recirculation amounts, with the increase of recirculation amounts, Li+concentration increases, the intercept amount of Li+reduces.(2) In this study, use water without Li+to leach waste from second cycle, during this proess, when the waste density increases, Li+concentration decreases; The experiment results shows that the tracer substances leaching is a relatively slow process, the greater density of waste, the tracer residue in the waste is more difficult to leach, for the bioreactor landfill which adopted leachate recirculation, to a certain extent, to increase the density of landfill can increase the time of water and pollutants exist in waste, it is conducive to degradation and stability of pollutants, it also can help to accelerate the process of bioreactor landfill stabilization.(3) Use the common kinetic models which describing the leaching process to simulate the experimental data, by the simulation result, the simulation results of the second-order kinetics equation and Elovich model are better than the first-order kinetics equation,the second-order kinetics equation is better than Elovich model.(4) Use the solute migration models which established in this study to simulate the experimental data of4#dustbin, by the simulation result, the model has a certain reliability, it also has a certain reference value when use it to forecast solute migration discipline after leachate recirculation.