Optimization of Fenton treatment process for degradation of refractory organics in pre-coagulated leachate membrane concentrates

Untreated leachate membrane concentrates are a threat to the environment. In our study, effective removal of contaminants in pre-coagulated leachate membrane concentrates was achieved using the Fenton process. The Fenton process was optimized using the response surface method, and the maximum total organic carbon (TOC), chemical oxygen demand (COD), and chromaticity reduction efficiencies reached 68.9%, 69.6%, and 100% under the conditions pH 2, H2O2 concentration 1 mol/L, and Fe2+ concentration 17.5 mmol/L. The COD concentration was reduced from 1120 to 340 mg/L. The H2O2 concentration was the key factor affecting the TOC removal efficiency. Slow, continuous addition of the Fenton reagents improved the H2O2 utilization rate, which improved the TOC removal efficiency. Fourier-transform infrared and three-dimensional fluorescence spectroscopy showed that the majority compound of the removed organic material was humic acid. Our study provides guidelines for the treatment of leachate membrane concentrates in engineering applications.