Simultaneous antibiotic resistance genes reduction and membrane fouling mitigation by a hybrid process of magnetic activated carbon adsorption and ultrafiltration for wastewater reuse

Antibiotic resistance genes (ARGs) and dissolved effluent organic matter (dEfOM) in reclaimed water are potential risks for landscape reuse or ecological water compensation. Adsorption process showed high advantage during advanced wastewater treatment. To improve the recovery of adsorbent during application, magnetic activated carbon (MAC) was successfully prepared by loading ferromagnetic oxide on powder activated carbon and used as pre-treatment for ultrafiltration (UF) to simultaneously reduce dEfOM and ARGs. Meanwhile, the mitigation mechanism of membrane fouling by MAC was further investigated. Results showed that the removal efficiency of dEfOM and ARGs by a hybrid process of MAC-UF was superior to the individual process. dEfOM reduction was more than 60%, and the maximum removal of sulI, sulII, sulIII, tetM, tetQ and tetW reached 3.09, 3.77, 1.96, 4.33, 3.85 and 2.75 log units, respectively. Their reduction was mainly attributed to the surface adsorption of MAC as well as physical retention by UF. Based on correlation analysis, the reduction of tetM, tetQ, tetW were strongly correlated with that of fulvic acids, soluble microbial products and humic acids (p < 0.01). Standard blocking and cake filtration were the dominant membrane fouling mechanisms throughout the filtration process. After MAC pretreatment, membrane fouling was significantly reduced, especially for the irreversible hydraulic resistance (88.9%). In a word, this study provided a new approach for dEfOM and ARGs reduction, and may have important significance for reclaimed water security and UF technology promotion.