We agree with the suggestion of this reviewer. The two-stage biofilms located in the activated carbon column and on the UF membrane synergistically, can be conducive to the removal performances. However, the mechanisms of the two-stage biofilm, such as bacterial and metazoan communities, membrane fouling and dissolved oxygen transfer, should be further investigated to enhance the removal efficiency and stability of this system. The research gap has been added in the Conclusion and is as follow: To sum up, the results show that the proposed BAC-UF system can be effective in the treatment of river water polluted by PPCPs, conventional organic pollutants and ammonia nitrogen. Besides, the results of this analysis can have significant implications for the conven-tional UF operation procedure and the ozone-activated carbon process, providing a simple decentralized approach to drinking water treatment for the areas where source water is contaminated with PPCPs.
Point 3: Line 46-52: & line 84-85 “Ultrafiltration (UF) as an emerging alternative technology to conventional water treatment processes, has been widely used to remove pollutants such as particles, colloids, bacteria, and viruses, thus reducing the risk of water-borne diseases [10].