Comprehensive investigation of landfill leachate treatment by integrated Fenton/microfiltration and aerobic membrane bioreactor with nanofiltration

Due to the presence of refractory organic pollutants and toxicity compounds, the choice of the best alternative for the landfill leachate treatment becomes a challenge. In this study the integration of aerobic membrane bioreactor with nanofiltration (MBR-NF) and hybrid Fenton-microfiltration process also with nanofiltration (FMF-NF) were compared for the treatment of landfill leachate. The roles of individual process on the organic and inorganic matter removal and toxicity reduction were discussed. By analyzing the residual compounds of each individual process, the mechanism of organic matter change during these processes was qualitatively investigated. The FMF process had the best percentage of color (47 %), COD (67 %), ammonia nitrogen (37 %) and toxicity (100 %) removal compared to MBR, which demonstrated removal of 31, 22, 27 and 44 % for the same parameters, respectively. NF plays a crucial role as a polishing stage, allowing for final removal rates >99.9 % and 95 % for color, 88 % and 95 % for COD and 92 % and 80 % for ammonia (MBR-NF and FMF-NF treatment routes, respectively), producing high quality and nontoxic permeates. Furthermore, the diversity of compounds identified with different properties and toxicity patterns emphasizes the complexity of the relationships that occur in these aqueous matrices and the effects they cause. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.