Study On The Treatment Of Concentrated Solution Proudeced In Nanofiltrating Process Of Landfill Leachate Using Fenton Combined With Flocculation

The primary manner of treating city landfill is sanitary landfill in china.Landfill leachate which has prouduced form the process of lanfill is a complex wastewater which is hard to treat.The technology of MBR combined with nanofiltration is used to treat landfill leachate proudecing from The Qing Dao Xiao Jianxi landfill. Concentrated solution proudeced in nanofiltrating process is recirculated to the landfill.It can treat the concentrated solution temporarily.But if the recirculation keeping too long,it will cut down the change cycle of the nanofiltration membrane and increase the running cost.To aim at afore-mentioned problem,Fenton combined with flocculation is adopted to treat this concentrated solution to find a economical and effectual method.The effects on treating the concentrated solution using sole flocculation and Fenton oxidation has been studied respectively.The result indicated that both the two method can't achieve the purpose of treating the sample effectually.The experiment results of treat concentrated solution using Fenton combined with flocculate showed that it can improve the biodegradability of the concentrated solution effectually.The optimal operation conditions of Fenton oxidation were determined as follows:the initial pH=7,the dosage of the H₂O₂= 0.9g/L,the dosage of the FeSO₄ =3g/L and the time of reaction=20min.After Fenton oxidation,the condition of flocculation is that the initial pH of 4,the PFASSi dosage of 20mL/L and the style of stir of 2 min quickly(100r/min) and 3 min slowly(60r/min).The COD, BOD and the chroma of the supernarant is 2011ml/L,835 ml/L and 128,respectively. The corresponding removal rate is 82.4%,63.7%and 87.5%,respectively. BOD/COD of supernarant is 0.415,and it can be biodegrated easily.According to the result of the experiment and the currently available technics flow of the landfill's sewage treatment plant,a alteration project was designed and the technical and economic evaluation was made.The investment of this alteration project is about 240 thousand RMB,and the cost of running is 14.1yuan/m³.The sewage treatment plant can treat the concentrated solution using this alteration project.