Research On Treatment Of Advanced Landfill Leachate By Sustained-released Potassium Ferrate Combined With Hydrogen Peroxide

With the rapid development of society,the material living conditions of the people have been greatly improved.And the total amount of domestic waste is also growing rapidly.At present,the main treatment method for municipal solid waste is sanitary landfill.However,with a complex chemical reaction and external precipitation and other factors,the landfills will produce a large number of toxic and harmful landfill leachate.Landfill leachate has the characteristics of complex components,widely varied quantity,multiple types of pollutants and high concentrations,which is difficult to be treated by biologic processes.It is difficult to reach the emission standards just by biologic processes.Therefore,it becomes one of the research hotspots in recent years to find an efficient and rapid treatment method for landfill leachate.In this paper,I dealed with the advanced landfill leachate by the combination of physicochemical method and advanced oxidation method and studied on the treatment effect of leachate with potassium ferrate and hydroxyl radical created by Fenton-like.First,I researched the best treatment conditions and effect of landfill leachate with potassium ferrate alone.Then I tried to improve the quality of potassium ferrate,compounded the sustained-release potassium ferrate and studied the removal effect of COD_Cr,TP and NH₃-N in leachate by using the sustained-release potassium ferrate.Then the effect of leachate removal by the combined use of sustained-release potassium ferrate and hydrogen peroxide were studied and the optimal mass ratio,time,pH and other factors were determined.In the experimental stage of the treatment of advanced landfill leachate with potassium ferrate,it was concluded that high or low pH was not conducive to the degradation of organic pollutants in leachate by potassium ferrate.When the temperature was increased from 20?to 60?,the removal rate of COD_Cr,NH₃-N and TP in the advanced landfill leachate by potassium ferrate was almost unchanged.The optimum treatment conditions were as follows.When the mass ratio of potassium ferrate to leachate COD_Crr of m?K₂Fe O₄?/m(COD_Cr)was 4:3,pH=5 and the reaction time was twenty minutes,The removal rates of COD_Cr,TP and NH₃-N in leachate could reach 53.8%,57.9%and 40.1%,and the treatment effect was obvious.In the experimental stage of the treatment of advanced landfill leachate with sustained-release potassium ferrate,it was concluded that sustained-release potassium ferrate was more stable in leachate and had better sustained release effect.When used equal quality sustained-release potassium ferrate,the rate of removal of COD_Crr from leachate was higher than using potassium ferrate.Temperature had almost no influence on the treatment effect.The optimum treatment conditions were as follows.When the mass ratio of potassium ferrate to leachate COD_Crr of m?sustained-releaseK₂FeO₄,basedonthemassofK₂FeO₄contained therein?/m(COD_Cr)was 4:3,pH was controlled at 4 and the reaction time was thirty minutes,The removal rates of COD_Cr,TP and NH₃-N in leachate could reach 58.9%?64.9%?43.6%,and the treatment effect was obvious.In the experimental stage of the treatment of advanced landfill leachate with sustained-release potassium ferrate and hydrogen peroxide,it was concluded that in the combined treatment action sustained-release potassium ferrate and hydrogen peroxide had shown good synergistic effect.The Fenton-like reaction produced a large amount of·OH with strong oxidative property,and the COD_Crr removal rate for advanced landfill leachate was higher than that of K₂FeO₄ and sustained-release K₂FeO₄.Potassium ferrate was used less,with cost advantages.When the temperature was increased from 20?to 60?,the removal rate of COD_Crr and TP in the advanced landfill leachate by potassium ferrate was almost unchanged,but the removal rate of COD_Crr and NH₃-N had increased slightly.When m?sustained-release K₂FeO₄,based on the mass of K₂Fe O₄ contained therein?/m(COD_Cr)was 4:3,the initial pH was 4.0,and 0.4 mL of hydrogen peroxide was added after thirty minutes reaction,and the reaction was continued for sixty minutes,The removal rates of COD_Cr,TP and NH₃-N in leachate could reach 74.5%?77.3%and 49.2%.