Study On The Treatment Of Landfill Leachate By Fenton Method And Its Engineering Design

Landfill leachate is high concentrations of waste water containing a wide range of pollutants, which is generated in the course of landfill. To collect and treat landfill leachate effectively, and to refine and improve treatment methods continuously become a hot research both at home and abroad in recent years. Based on summarizing and analyzing the existing treatment methods, the simple process of Fenton oxidation treatment of landfill leachate were studied.Intermittent treatment of landfill leachate by Fenton method was studied first. The leachate sample was pretreated by purge aeration, and the ammonia removal rate reached more than 50%. The Fenton oxidation was carried on on the basis of the pretreatment. By the study of initial pH value,H₂O₂ dosage,H₂O₂/Fe²⁺ molar ratio and reaction time, the results showed that the impact level of reaction conditions to the treatment effect was: H₂O₂ dosage> reaction time> the initial pH value of> H₂O₂/Fe²⁺ molar ratio. The best process parameters for intermittent treatment of landfill leachate by Fenton method was H₂O₂ dosage of 0.06mol/L,H₂O₂/Fe²⁺ molar ratio of 2:1,reaction time of 3h and the initial pH value of 4.Kinetics of intermittent treatment of landfill leachate by Fenton method was studied, and second-order reaction model was set up, fitting the kinetic equation for r=k[COD]_t², in which the reaction rate constant k=2170.3159exp(-35299.7/RT).At room temperature the time-varying COD formula: [COD], = (0.001115t+0.000708)^-1.Continuous reactor was set up on the basis of intermittent reaction, and continuous treatment of landfill leachate by Fenton method was studied, the effect of COD removol was studied and the residence time distribution was determined, the results showed that with the reduction of feed flow, the system average residence time increased, and COD removal rate was also increased. In the flow of 0.9L /h, the system average residence time was 72.83min, and COD removal rate reached 73.24%. Analysis of the system non-dimensional variance showed that the reaction was closer to plug flow reactor with the lower feed flow.Based on the small test of continuous reaction, a leachate treatment project was designed in the background of a small landfill in Taizhou city, whose handling capacity was determined by 200m³/d.The process was determined by technology selection based on processing requirements.The selection and designing of the main equipments and ancillary equipments of every process was done, the specific configuration of every process was determined and the layout and the elevation were completed. Through economic accounting, the project cost was estimated 6.36yuan/t.