Comparative study of Fe0-H2O2, Fe0-PMS and Fe0-PDS systems for the removal of refractory organics from bio-treated landfill leachate

Aiming at the excellent performance of advanced oxidation technology (AOP) in removing organic matter, the efficiency and mechanism of Fe0 activated H2O2, PMS and PDS in the removal of refractory organic matter in bio-treated landfill leachate (BTL) were systematically compared. The results showed that the removal effect of the three systems on organic matter was affected by the dosage of oxidant, the dosage of zero-valent iron, the initial pH value and the reaction time. After treatment with the three systems, the content of humic substances and aromatic organics in MBR effluent and the degree of molecular polymerization could be effectively reduced. Due to different ROS dominance in the three systems, there were differences in the efficacy of organic matter removal. The activation mechanism of Fe0 included homogeneous activation of Fe2+ and heterogeneous activation of in situ formation of iron oxides. Finally, considering various factors, such as the organic removal effect, oxidant toxicity, sludge yield, economy and potential impact of byproducts, the Fe0-H2O2 system was superior to the other systems in the selection of treating refractory organics in landfill leachate MBR effluent.