Removal of Organic Micro-Pollutants by Conventional Membrane Bioreactors and High-Retention Membrane Bioreactors

Round 1

Reviewer 1 Report

applsci-751310. Removal of organic micro-pollutants by conventional membrane bioreactors and high-retention membrane bioreactors

GENERAL COMMENTS

The review paper summarizes the recent advances for the removal of organic micropollutants from wastewater in conventional and high retention membrane bioreactors.

Due to its potential impact on health and the environment, the removal of organic micropollutants from wastewater is of great interest. In this field, the membrane bioreactors, in their conventional and newer configurations, have an undoubted application potential. In mi opinion, the manuscript is clear and well presented. I suggest this paper should be accepted after minor revisions.

In general, the text should be revised to eliminate typographical errors and to check references.

SPECIFIC COMMENTS

1. Introduction

• Please change “nanofiltartion” (line 151)
• update information on commercial MBR providers is required (e.g. Hai et al., 2018). The Zenon´s modules are now supplied by Suez. In terms of treated water capacity, the market is dominated by two companies: Suez and Beijing Origin Water (lines 159-161)

Faisal I. Hai, Kazuo Yamamoto, Chung-Hak Lee. Membrane Biological Reactors: Theory, Modeling, Design, Management and Applications to Wastewater Reuse - Second Edition, IWA Publishing, 15 oct. 2018.

2. MBR types and configuration

2.1.

• MWCO of MF/UF membranes in MBRs are well above the MW of most of the OMPs. Therefore, it seems that size exclusion cannot occurs. Although adsorption onto the membrane surface can take place, removal rates do not look like it is going to be high, and also it will tend to decrease over time. Do membrane parameters really influence pollutant removal? (lines 240-241). In Table 1, when different membranes (MF and UF) are compared, the results are similar. Many authors reported that biodegradation/bioadsorption was the main mechanism.
• There is an erroneous reference in Table 1. Reference 69 appears in different studies. The reference 76 does not appear in this Table. For the reference 71 there are negative removal values and greater than 100.
• In order to analyse the extensive information presented, it seems of interest to make some kind of classification in the elimination of OMPs. Perhaps due to the types of membrane, the chemical nature of OMP, whether it is synthetic or real water, the mechanism that governs elimination...

2.1.

• The quote “Monsalvo et al. (2014)” must be corrected (lines 382 and 408).
• The text regarding the production of biogas in AnMBR does not seem to be related to the elimination of OMPs (lines 443-454).
• As in the previous section, some type of classification of the studies would help a detailed interpretation of the information.

3. High retention membrane bioreactors

• Comparison between different technologies is not the fundamental objective of the study and it extends the length of the text. I would delete Table 4. This information can be found in other studies that can be cited.
• Change “ESPS” by EPS (line 539)
• MWCO refers to membrane not to molecules (line 541).
• Detailed information about MDBR can also avoided (Fig. 4) and the section should focus on the elimination of OMPs.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Only format concerns.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx