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

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 30 mA cm(-2), FeSO4 dosage of 10 mM, initial pH of 3, and cathode area of 20 cm(2), 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. (C) 2012 Elsevier B.V. All rights reserved.