Removal of Tetracycline Resistance and Bacteria Diversity Changes by Advanced Membrane Process

Abstract

Rejection of tetracycline resistant bacteria (TRB) and tetracycline resistance genes (TRGs) in the secondary effluent of a lab-scale anaerobic/anoxic/oxic (lab-AAO) system and real-scale AAO by forward osmosis (FO) membranes was investigated. Changes in the bacteria diversity in the FO membrane process were also studied. High-throughput sequencing and the real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) were used for identifying diversity changes in the microorganisms of the FO process and the abundances of eight TRGs (namely, tetA, tetB, tetC, tetE, tetM, tetO, tetS, and tetX), respectively. Results revealed that both TRB and TRGs could be effectively removed by different FO membranes in the active layer facing the feed solution or the draw solution, which were defined as AL-FS and AL-DS. Three genera, consisting of Proteobacteria, Bacteroidetes, and Actinobacteria, were identified as potential TRB at the phylum level. This study reveals that an FO membrane can be a good process for reducing the health risks caused by TRB and TRGs in reclaimed water.