Removal of refractory organic matter from membrane bioreactor-treated landfill leachate effluent by microwave activation of peracetic acid

Abstract

Microwave-activated peracetic acid (MW/PAA) advanced oxidation system was developed in this study for the removal of organic matter in the effluent from a membrane bioreactor-treated landfill leachate effluent (MBR effluent). The results show that the MW/PAA system showed an obviously better degradation effect on the refractory organic matter than that of other controlled systems. Under conditions of PAA concentration = 60 mM, MW output power = 160 W, and initial pH = 7.8, the removal efficiencies for UV254 and CN were 53.59 % and 95.56 %, respectively. The R-O• and 1O2 are the major contributors for the degradation of organic matter via radical and non-radical pathways, respectively, in the MW/PAA system. After treatment, the refractory organic matter featuring with small-molecular weight and high fluorescence frequency in the MBR effluent were significantly degraded. The MW/PAA system has good resistance to common anions in water, and Cl− has an obvious promotional effect on the removal of refractory organic matter. The MW/PAA system not only has a selective removal effect on various aromatic organics but also reduces the biological toxicity after the reaction, and the removal effect of the refractory organic matter in different kinds of landfill leachate shows the application potential and wide applicability of the system in the treatment of complex wastewater.