Study On The Treatment Of Aged Landfill Leachate

Sanitary landfill is the main method for processing municipal landfill these days,but it will produce landfill leachate which is very harmful to our environment. If the landfill leachate is discharged into the environment,the soil and groundwater environment will be polluted severely.The aged landfill leachate is a kind of liquid,which contains lots of toxic and nocuous inorganic and organic matters,whose COD is very high while biodegradability(B/C) is low.Pollutant concentration of the landfill leachate used to change largely,which has apparently foul smell.The treatment schedule is physical-chemistry combined together with biotechnology,which can not do the aged landfill leachate.The aged landfill leachate used in this dissertation comes from Chengdu Changan Municipal Wastes Sanitary Landfill,which is by the Fenton's reagent, ultrasonics and ultrasonics-Fenton process.The optimum process conditions of the method are achieved.The major achievements in the dissertation are as follows:(1) The purpose of this experiment is to operate Fenton oxidation process efficiently.The total COD removal of the leachate by Fenton oxidation is 72.9% under the following oxidation conditions:60min reaction time,0.015mol/L FeSO₄·7H₂O,the H₂O₂ / FeSO₄·7H₂O ratio of 4 to 1,the optimum pH of 4 for the Fenton oxidation process and 8.0 for the coagulation process,reaching the sencod class standard of "Sewage Comprehensive Discharging Standard".(2) Irradiation COD removal efficiency increases with increased ultrasound power input.The effect of initial pH on COD removal is not obvious.(3)Ammonia nitrogen removal efficiency increases with increased initial pH. Ammonia nitrogen removal efficiency increases gradually with extended reaction time,but increases little after 180min reaction.Increased ultrasound power input makes for ammonia nitrogen removal efficiency.(4)The purpose of this experiment is to operate Ultrasonics-Fenton process efficiently.The total COD removal of the leachate by Fenton is 79.87%.The optimum condition in this research are these:power input of 75W,90min reaction time,0.03mol/L FeSO₄·7H₂O,the H₂O₂/FeSO₄·7H₂O ratio of 3 to 1,the optimum pH of 5 for the process and 8.0 for the coagulation process.