Electro-Fenton treatment of concentrates generated in nanofiltration of biologically pretreated landfill leachate

• Published in: Journal of hazardous materials 2012-08, Vol.229-230, p.115-121
• Main Authors: Wang, Yujue, Li, Xinyang, Zhen, Limin, Zhang, Heqing, Zhang, Ying, Wang, Chengwen
• Format: Article
• Language: English
• Subjects: Applied sciences; carbon; Carbon - chemistry; Chemical engineering; Electro-Fenton; electrochemistry; Electrodes; Exact sciences and technology; Ferrous Compounds - chemistry; ferrous sulfate; General treatment and storage processes; hydrogen peroxide; Hydrogen Peroxide - chemistry; iron; Landfill leachate; landfill leachates; Membrane separation (reverse osmosis, dialysis...); nanofiltration; nitrogen content; oxidants; Oxidation; oxygen; pollutants; Pollution; Polytetrafluoroethylene - chemistry; Reactors; TOC removal; Ultrafiltration; Wastes; Water Pollutants, Chemical - chemistry; Water Purification - methods
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2012.05.108

► The E-Fenton technology is an effective method for degrading refractory organics. ► The carbon–PTFE cathode is effective in electrochemically producing H2O2. ► The E-Fenton system can produce enough H2O2 in situ to treat leachate concentrates. ► Optimal reaction conditions for E-Fenton treatment of leachate is determined. ► Technical feasibility of E-Fenton for treating leachate concentrates is proved. The electro-Fenton (E-Fenton) treatment of landfill leachate concentrates was investigated in this study. The concentrates were generated from nanofiltration of biologically pretreated landfill leachate, and contained high concentrations of refractory organics and inorganic salts. During the E-Fenton treatment, H2O2 was electrochemically produced at a carbon–polytetrafluorethylene (PTFE) cathode with oxygen feeding. The in situ generated H2O2 then reacted with Fe2+ that was added into the concentrates to bring about Fenton oxidation of the refractory organics in the concentrates. The effectiveness of the E-Fenton treatment of the concentrates was appraised in terms of its removal efficiency of total organic carbon (TOC) of the concentrates. The effects of FeSO4 dosage, current density, initial pH of the solution, and cathode area on the process performance were also evaluated. Under optimal reaction conditions that included a current density of 30mAcm−2, FeSO4 dosage of 10mM, initial pH of 3, and cathode area of 20cm2, the TOC and total nitrogen (TN) removal efficiencies were 82% and 51% after 6h of the E-Fenton treatment. The results indicated that the E-Fenton technology could produce sufficient amounts of advanced oxidants in situ to effectively degrade the refractory organic pollutants in high-strength leachate concentrates.