Pilot-Scale Biological Activated Carbon Filtration–Ultrafiltration System for Removing Pharmaceutical and Personal Care Products from River Water

Round 1

Reviewer 1 Report

The paper is interesting.
I recommend publication only if the following issues can be addressed.

- The innovation of this research needs to be better explored. 

- Lines 33-38: You should mention that discharge of PPCPs degrades water quality and thus it cannot be directly used for potable water (via desalination) and industrial applications. Cite the following references:

Panagopoulos, A. (2021). Energetic, economic and environmental assessment of zero liquid discharge (ZLD) brackish water and seawater desalination systems. Energy Conversion and Management, 235.

Panagopoulos, A. (2021). Techno-economic assessment of Minimal Liquid Discharge (MLD) treatment systems for saline wastewater (brine) management and treatment. Process Safety and Environmental Protection, 146, pp. 656-669. 

Panagopoulos, A. (2021). Study and evaluation of the characteristics of saline wastewater (brine) produced by desalination and industrial plants. Environmental Science and Pollution Research, 1-14.

- How many replications you performed for your experiments?

- Conclusion: Discuss the applicability of your findings/results and future study in this field.

- Conclusion: Make it as one or two paragraphs.

- Language editing is recommended.

- Table 1: What is the salinity (in mg/L) of the samples ?

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

In this study, the authors investigated the removal efficiency of Biological activated carbon (BAC) and biofilter coupling ultrafiltration (UF) system process for the treatment of surface water contaminated by pharmaceutical and personal care products (PPCPs).

The study was carried out in the pilot-scale BAC-UF process with a treatment capacity of 0.16 m3/h.

After the process, the water quality was analyzed including CODMn, UV254, NH4+-N, and PPCPs.

They concluded based on the results from this study that the BAC-UF process is a promising process for producing clean drink water.

I can see very well-defined experiments and produced good results.

I also believe that this study will be useful and of interest to many readers.

Moreover, the authors present the results properly.

They also discussed their results in detail and put the difference in their results compared to the data with the literature.

However, there are some mistakes in the writing of the paper.

Please also see the attached file for my corrections/comments.

Overall, the manuscript can be accepted after the minor correction/revision to be published in the journal of Water.

Comments for author File: Comments.pdf

Author Response

Thank you very much for your kind reminder. We agree with the suggestion and comments of the reviewer. All comments have been revised one by one, and the modifications are highlighted in yellow in the marked revised manuscript. Two native English-speaking colleagues help us verify the manuscript. Hope the revised manuscript would be more satisfactory. Thanks again for your patient review.

Reviewer 3 Report

Greetings, Editor thank you for providing me with the opportunity to review the article. I reviewed the article with title Pilot-scale biological activated carbon filtration-ultrafiltration (BAC-UF) system for removing pharmaceutical and personal care products (PPCPs) from surface water``.  The article topic is intriguing and promising in the area. Overall, the article structure and content are suitable for the WATER journal. I am pleased to send you major level comments, there are some serious flaws which need to be corrected before publication. Please consider these suggestions as listed below.

1. The title seems good, but the abstract seems to be fine. Please add one problem statement line in abstract to justify this sentence ``the long-term pilot-scale study is urged to be investigated.``.
2. Research gap should be delivered on more clear way with directed necessity for the future research work.
3. Introduction section must be written on more quality way, i.e., more up-to-date references addressed. Please target the specific gap such as 2015-2021 etc.
4. Page 1 Line 38. Please cite this reference with existing reference 3….Role of nanotechnology for design and development of cosmeceutical: application in makeup and skin care.
5. The novelty of the work must be clearly addressed and discussed, compare previous research with existing research findings and highlight novelty.
6. What is the main challenge? Why author choose this material? Please highlight in the introduction part.
7. Page 2 Line 55 need a reference. Please consider these at end of this sentence……The oxidation method exhibited a fast reaction speed and high removal efficiency…(i) Role of nanomaterials in the treatment of wastewater: A review (ii) Advances and challenges in developing efficient graphene oxide-based ZnO photocatalysts for dye photo-oxidation.
8. The main objective of the work must be written on the more clear and more concise way at the end of introduction section.
9. Please check the abbreviations of words throughout the article. All should be consistent. Please revise your paper accordingly since some issue occurs on several spots in the paper.
10. Please add chemical reagents section and stated all chemical with brand specifications.
11. Regarding the replications, authors confirmed that replications of experiment were carried out. However, these results are not shown in the manuscript, how many replicated were carried out by experiment? Results seem to be related to a unique experiment. Please, clarify whether the results of this document are from a single experiment or from an average resulting from replications. If replicated were carried out, the use of average data is required as well as the standard deviation in the results and figures shown throughout the manuscript. In case of showing only one replicate explain why only one is shown and include the standard deviations.
12. Please use Fig. or figure? It very confusing. Article should be in one pattern. Please follow the journal guidelines. Please revise your paper accordingly since some issue occurs on several spots in the paper.
13. Please provide high quality image of figure 1.
14. Please use one style for units such as m³/h or m³h^-1 Please revise your paper accordingly since some issue occurs on several spots in the paper.
15. Please add a comparative profile section to compare your results and prove how it better than previous.
16. Section 4 should be renamed by Conclusion and Future perspectives. Conclusion section is missing some perspective related to the future research work, quantify main research findings, highlight relevance of the work with respect to the field aspect. In the present form conclusion is very weird.
17. To avoid grammar and linguistic mistakes, Major level English language should be thoroughly checked. Please revise your paper accordingly since several language issue occurs on several spots in the paper.
18. Reference formatting need carefully revision. All must be consistent in one formate. Please follow the journal guidelines.

 

 

 

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

Title: Pilot-scale biological activated carbon filtration-ultrafiltration (BAC-UF) system for removing pharmaceutical and personal care products (PPCPs) from surface water.

##Overall comments

The authors described a pilot-scale BAC and BAC-MF technology to remove PPCPs from the river water (Foshan, Guangdong, China). The authors have used pump water from the river to the storage tank and used supernatant water from the storage tank (Fig. 1) for this experiment. Results have not been well discussed. The authors reported the results with an average value and standard deviation. However, it must need statistical analysis. The reviewer suggests at least a t-test analysis. Therefore, it needs a Major revision.

##Comments on the title, Abstract, and References 

1. Authors should avoid abbreviations in the title and the abstract. 
2. Authors may revise the title to include river water instead of surface water.
3. References should be according to the journal format.

##Comments on Introduction section

4. Line 44-45: Ultrafiltration (UF) as emerging technology, has been widely used to remove pollutants such as particles, colloids, bacteria and viruses, reducing the risk of water-borne diseases and …UF membranes cannot effectively rejected these soluble substances”. Please clarify, why ultrafiltration cannot remove the PPCPs since it can remove bacteria and viruses.

##Comments on Results and discussion

6. Please add t-test results in Table 1 for each parameter to understand the significant differences. Authors may provide data in the supporting information file.
7. Why the same trend of increase or decrease in graphs (Fig. 1) was observed in Fig. 1(c). Why is the DO concentration of BAC-effluent sometimes higher than the Raw water. Please explain it in the manuscript. The reviewer suggests statistical analysis using a t-test (Raw water- BAC-Effluent and Raw water – BAC/UF-effluent).
8. The reviewer suggests evaluating the statistical t-test for Figures 4.
9. t-test results should be included in Table 2. Why is the standard deviation of Erythromycin showing a high value? 
10. Please look at the curve of BAC/UF; there was a symbol missing in near 85 days. Please show each symbol.
11. The conclusion may be revised.             

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors improved significantly their manuscript, which is now ready for publication. I recommend acceptance for publication.

Author Response

Thank you very much for your support and help.

Reviewer 3 Report

Dear Authors, i reviewed again the revised version. I would like to recommend the publication in present form. Authors shows sincere efforts during revision.

Author Response

Thank you very much for your support and help.

Reviewer 4 Report

Title: Pilot-scale biological activated carbon filtration- ultrafiltration (BAC-UF) system for removing pharmaceutical and personal care products (PPCPs) from river water.

The authors have improved the manuscript. However, I still have some concerns. The manuscript could be accepted for publication after a minor revision.

Comments:

1. Authors should avoid abbreviations in the title. Authors should add a list of abbreviations before the references.
2. Please avoid repeating the full name and abbreviation throughout the manuscript if you used the first-time abbreviation.
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]. Size exclusion is considered the primary removal mechanism for the UF. However, in the case of the PPCPs with a small molecular weight (typically < 600 Da), UF membranes also cannot effectively reject these PPCPs, but nanofiltration and reverse osmosis are able to remove these PPCPs based on the thin-film composite”. Sorry, but I don't see why UF can reject viruses and bacteria but not PPCPs. Is it true that the molecular weight of viruses and bacteria is more than that of PPCPs? Please elaborate.
4. The authors should include some information regarding the biological degradation of PPCPs by microorganisms in the introduction section.
5. Line 53-55: “The combined process with ultrafiltration may be another promising choice, featuring a comparable removing performance as the nanofiltration and low operational cost”. Have the authors compared the BAC-UF performance to that of nanofiltration?
6. I strongly suggest that the authors explain how they performed the t-tests. Please include the sample size (n) or degree of freedom (df).
7. Please show the t-value and p-value in a scientific view (e.g., 2.79E-4 would be P <.001).
8. Line 161-176: Please delete the name of medicinal compounds not used for this study.
9. Point 6: Why the same trend of increase or decrease in graphs (Fig. 1) was observed in Fig. 1(c). Why is the DO concentration of BAC-effluent sometimes higher than the Raw water. Please explain it in the manuscript. The reviewer suggests statistical analysis using a t-test (Raw water- BAC-Effluent and Raw water – BAC/UF-effluent).

Response 6: Thanks very much for this comment. The same trend (Figure 2) was mainly due to the stable removal ability of BAC and UF for organics, causing the removal restriction. The periodic backwash (7days) of BAC caused sometimes the dissolved oxygen concentration of BAC-effluent higher than that of raw water. After the gas scrubbing and the hydraulic backwashing, the dissolved oxygen detection of the effluent was carried out, resulting in the above results for dissolved oxygen. Besides, the t-test was used and proved the significant difference between BAC-Effluent and BAC/UF-effluent.

Thanks for the response. Please include it in the manuscript.

10. What is the utility or deterioration of PPCPs sludge after removing it from river water? If possible, please add at least one paragraph.

Author Response

Please see the attachment.

Author Response File: Author Response.docx