Microwave-enhanced iron–carbon-activated hydrogen peroxide process for the advanced treatment of semi-aerobic aged refuse biofilter effluent

Abstract

In this study, a microwave-enhanced and iron–carbon (Fe–C)-activated H₂O₂ process (MW/Fe–C/H₂O₂) was applied to the advanced treatment of biologically treated effluent from a semi-aerobic aged refuse biofilter (SAARB). The enhancement achieved by introducing MW radiation into the Fe–C/H₂O₂ process was comprehensively investigated. It was found that the removal effect of the MW/Fe–C/H₂O₂ process on organic matter in the effluent was better than that of other controlled processes. Three-dimensional excitation and emission matrix (3D-EEM) fluorescence spectra showed that the degree of molecular condensation and molecular weight of dissolved organic matter in the effluent were greatly reduced, and humus was largely destroyed and mineralized. When the H₂O₂ dosage was 10 mL L⁻¹, the Fe–C dosage was 1 g L⁻¹, the MW output power was 240 W, the initial pH was 3, and the reaction time was 10 min, the total organic carbon (TOC), absorbance at a wavelength of 254 nm (UV₂₅₄), and color number (CN) removal efficiencies from the effluent were 28.95%, 40.88%, and 75.62%, respectively. By characterizing the iron–carbon materials before and after the reaction, it was found that the iron–carbon materials contained a variety of active substances such as zero-valent iron (Fe⁰) and iron oxides, which can participate in homogeneous and heterogeneous Fenton reactions with H₂O₂, and MW radiation as an external energy source can strengthen the above process to a certain extent. This will accelerate the removal of organic matter from the effluent of a SAARB.