Process Design And Experimental Study On The Treatment Of Landfill Leachate By Biochemical Coupling Advanced Oxidation

With the rapid development of the city,the continuous increase of social production activities and the continuous improvement of people's quality of life,garbage waste has also increased dramatically.At present,the main way of garbage disposal in China is sanitary landfill disposal,the leachate produced by landfill waste has many problems,such as various types of pollutants,high concentration,and imbalance of nutrient elements.According to the characteristics of landfill leachate,the biochemical-advanced oxidation-biochemical combined treatment process was used in this paper,we studied the removal effect of two-level A/O-microelectrolysis-Fenton-coagulation sedimentation-MBR process on landfill leachate pollutants,which provides reference for practical engineering application.Through the analysis of all process conditions and influencing factors,the following conclusions are drawn:(1)We analyzed the main factors affecting the operation of two-level A/O process.The result shows that the optimal control conditions for each factor are:pH 6.0?8.5,reaction temperature 30?35?,denitrification C/N ratio 4:1,the reflux ratio 600%?1000%,and the dissolved oxygen in the nitrification tank 2?3 mg/L.Under these conditions,the two-level A/O system has better effect on pollutant removal,and the removal rates of COD and ammonia nitrogen are 72-83%and 94-99%,respectively.(2)After the treatment of two-level A/O system,we studied the effects of microelectrolysis,Fenton and coagulation precipitation on the effluent quality using single factor experiments,respectively.The results show that the optimal conditions for iron-carbon microelectrolysis reaction are:influent pH 3,reaction time 90 min,solid-liquid ratio 360 g/L;the optimal conditions for Fenton reaction are:influent pH 3,the reaction time 90 min,the dosage of FeSO4·7H2O 0.4 mL/L,and the dosage of H2O2 3 mL/L;The optimal condition for coagulation precipitation reaction is:the optimal dosage of PAM 2 mL/L.Through the continuous operation of microelectrolysis-Fenton-coagulation sedimentation process,after the system is operated stablely,the removal rate of COD is 67?84%,and the biodegradability in wastewater is also significantly improved.(3)In the MBR process experiment,under the conditions of temperature is 25?35?,dissolved oxygen is 2?3 mg/L,and working pressure is-0.1 Mpa?-0.03 Mpa,the removal rates of COD and ??from the microelectrolysis-Fenton-coagulation sedimentation water were 59-80%and 67-91%in MBR reactor,respectively.(4)After the combined treatment of two-level A/O-microelectrolysis-Fenton-coagulation sedimentation-MBR process,the removal rate of COD and NH3-N in this system are 99.3%and 99.9%,respectively,meeting the COD and NH3-N emission requirements in?Domestic waste landfill pollutant control standard?(GB 16889-2008).