The Treatment Of Refractory Organic Matters In The Tail Water By Multi-phase Fenton Process

Landfill leachate is a typical refractory wastewater,disposed with composite membrane process in general.MBR-NF is a common treatment and its effluent can meet emissions,which tail water is concentrate,and which processing is more complicated.The recovery of humic acids from leachate MBR + NF concentrate as a water-soluble fertilizer by nanofiltration(NF)and two-stage of ultrafiltration(UF)combined process is a promising alternative.However,a UF effluent generated from the process could not meet the requirements of the professional discharge standard,and remains a challenge to be addressed.Heterogeneous Fenton technology has been appealed a important advanced oxidation process in practical engineering for the treatment of tail water.A multi-phase Fenton process was conducted to investigate the treatment of the UF effluent generated from the recovery of humic acids from leachate MBR + NF concentrate by NF and two-stage UF hybrid process.The kinetics of the process for organic matter under optimal condition were also evaluated.This study would provide technical basis for practical application in the treatment of refractory organic matter.A loaded Cu-Ti-Fe/Al2O3 alloy ceramic particle deed as heterogeneous catalyst was prepared through sol-gel method.Scanning electron microscopy(SEM)and Brunauer,Emmett,and Teller specific surface area(BET)were employed to characterize the heterogeneous catalyst.Then the catalyst preparation conditions were optimized,and performances of alloy catalysts used in heterogeneous Fenton reaction were investigated.A multi-phase Fenton reaction synergistic system was formed,mainly including heterogeneous catalysts,magnetic field and FeSO4 dosage system.The system were performed to the treatment of the UF effluent,and the preparation conditions of catalysts were optimized as follows:stirring the sol of 5 h,soaking of 30 min,and calcination at 600 ? for 2 h.The UF effluent generated from the recovery of humic acids from leachate MBR+ NF concentrate by NF and two-stage UF hybrid process was used as tail water,and heterogeneous catalyst was prepared under the optimal conditions.A serial experiments were conducted to investigate the effect of operating factors on removal efficiency of organic matters in multi-phase Fenton reaction process.For the tail water with a COD of 643.6 mg/L and TOC of 198.2 mg/L,the optimal conditions were:dosage of the catalyst of 500 g/L,FeSO4 dosage of 0.5 g/L,n(H2O2):n(Fe2+)of 2:1,reaction time of 120 min with aeration and magnetic response,and no adjustment of the initial pH.Under the best conditions,the removal of COD,TOC and UV254 were 60.44%,43.64%and 66.56%,respectively.The removal efficiency increased 14.87%,18.02%and 19.3%respectively,compared to traditional Fenton process without catalyst and magnetic field.The degradation of organic matters in multi-phase Fenton reaction process corresponds with second-order kinetics equation.