Pharmaceuticals Removal by Ozone and Electro-Oxidation in Combination with Biological Treatment

Round 1

Reviewer 1 Report

Comments for Water 2537775

 

Journal : Water

Authors : Francesca Audino * , Judith Arboleda , Mira Petrovic , Ricard García Cudinach , Sonia Sanchis Pérez

Title : Pharmaceuticals Removal by Ozone and Electro-oxidation in Combination with Biological Treatment

The subject of the study is generally appropriate for Water, according to the journal aim and scope. This topic is interesting and current, because the removal of contaminants of emerging concern contained in hospital wastewaters, especially pharmaceuticals, is an extremely important issue in terms of its impact on the quality of receiving waters and, consequently, human health. While the research and findings are very interesting and of value for further understanding which methods can be effective in removing such contaminants, the manuscript needs improvement in several areas - please see the detailed comments/suggestions below for improvements to the manuscript.

Special comments:

·         Lines 143-144:  Duplicate drawings should be removed.

·         Lines 182-183: Duplicate drawings should be removed

·         Table 1:

What does the +/- notation mean, please explain. Is it the standard deviation? If yes, please provide the value of n.

·         Table 2:

·         Elemental analysis - please specify analytical methods or add a reference to the relevant manuscript fragment.

·         Figure 3. In the picture there are colors (blue/red) but in the description there is information about dash/solid bars. And as above, please specify analytical methods or add a reference to the relevant manuscript fragment.

·         Lines 276-278: lines to be removed

·         Lines 285-287: Please explain in the context of the information provided in Figure 3. What analytical methods were used in which determinations/samples?

·         Lines 731-732 versus 726-728: I don't understand: “It must be noted that pharmaceuticals for which no removal is shown were not detected in the wastewaters”.

·         All citations need to be carefully checked. I have highlighted some errors in color in the attached manuscript file.

Conclusion

Although the study in general outline is appropriate for Water, the manuscript needs some corrections. Therefore, I recommend it for publication after minor revisions.

Comments for author File: Comments.pdf

Author Response

Special comments:

• Lines 143-144:  Duplicate drawings should be removed. à done
• Lines 182-183: Duplicate drawings should be removed à done
• Table 1:

What does the +/- notation mean, please explain. Is it the standard deviation? If yes, please provide the value of n. à Added (lines 215-216)

• Table 2:

Elemental analysis - please specify analytical methods or add a reference to the relevant manuscript fragment. à Added (line 216)

• Figure 3. In the picture there are colors (blue/red) but in the description there is information about dash/solid bars. And as above, please specify analytical methods or add a reference to the relevant manuscript fragment. à corrected and added information (line 232-233)
• Lines 276-278: lines to be removed à done
• Lines 285-287: Please explain in the context of the information provided in Figure 3. What analytical methods were used in which determinations/samples? à added information (line 286-287)
• Lines 731-732 versus 726-728: I don't understand: “It must be noted that pharmaceuticals for which no removal is shown were not detected in the wastewaters”. à changes introduced for clarification in lines 739-740 and 754-755
• All citations need to be carefully checked. I have highlighted some errors in color in the attached manuscript file. à corrected, thank you!

Author Response File: Author Response.pdf

Reviewer 2 Report

Brilliant paper!

Just check for a typo in line 601, Figure 13 (CBZ) for missing O3-treatment data and lines 735 through 742 for inconsistencies in writing, and line 768 for a citation problem.

(Just one comment: Why didn't you apply UV-irradiation during O3 treatment?)

 Well, the authors did a great job on EO and on ozonation of APIs. 

I did wonder why the authors did just investigate ozonation without activation. We ordinarily do push ozonation reactions with catalysts (e.g. H2O2, UV-irradiation), because ozone itself can attack double bonds without catalysis, but HCs and substituents with just low efficiency. That is also mentioned in their paper. And, they reported that combined application of O3+EO pushes degradation of the investigated constituents. If you ask for improvement, I would suggest catalytic activation of ozonation. But you have to be careful with this suggestion, because it would need another series of experiments.

Author Response

Just check for a typo in line 601 (done), Figure 13 (CBZ) for missing O3-treatment data (it is under the green line -EO+O3-, along with the orange one -O3_EO-) and lines 735 through 742 for inconsistencies in writing (corrected, it was a citation problem: all the caption was copied instead of only “Figure 15”), and line 768 for a citation problem (done). 

(Just one comment: Why didn't you apply UV-irradiation during O3 treatment?) 

 Well, the authors did a great job on EO and on ozonation of APIs.  

I did wonder why the authors did just investigate ozonation without activation. We ordinarily do push ozonation reactions with catalysts (e.g. H2O2, UV-irradiation), because ozone itself can attack double bonds without catalysis, but HCs and substituents with just low efficiency. That is also mentioned in their paper. And, they reported that combined application of O3+EO pushes degradation of the investigated constituents. If you ask for improvement, I would suggest catalytic activation of ozonation. But you have to be careful with this suggestion, because it would need another series of experiments. à Added in the conclusions as future steps (Lines 818-819) and considered for future works, thank you. 

Author Response File: Author Response.pdf

Reviewer 3 Report

Journal: water

Manuscript number: water-2537775

Title: Pharmaceuticals Removal by Ozone and Electro-oxidation in Combination with Biological Treatment

 

The paper is interesting although some issues should be addressed before publication. Major revision is suggested to further improve its quality. Specific suggestions are provided below.

 

1.      What are the advantages of Advanced Oxidation Processes? (Applied Catalysis B: Environmental 2020. 273: 119051 and Separation and Purification Technology 2023, 312: 123412 may help and recommended to be cited)

2.      What is the biggest flash point in this article should be provided in the introduction?

3.      Did the author do a parallel experiment?

 

4. The chart format needs to be consistent, and the font size in Figure 15 is too small.

 

Author Response

1.      What are the advantages of Advanced Oxidation Processes? (Applied Catalysis B: Environmental 2020. 273: 119051 and Separation and Purification Technology 2023, 312: 123412 may help and recommended to be cited) à done (Lines 95-101), new references added: 19-21 

2.      What is the biggest flash point in this article should be provided in the introduction? à As highlighted in Lines 126-129, To the best of authors’ knowledge, this is the first study addressing the synergic effect of EO and O3 for the treatment of MBBR effluent treating real hospital wastewaters. 

3.      Did the author do a parallel experiment? à Yes, clarification was added (Lines 397-398) 

  

4. The chart format needs to be consistent, and the font size in Figure 15 is too small. All plots of the paper were reviewed and are now in the same format. Section “Validation with real hospital wastewater” has been reviewed and improved and plots have been consequently updated. 

Author Response File: Author Response.pdf