Electrode Material Optimization of Nitrous Oxide Recovery from Incineration Leachate in a ΔnosZ Pseudomonas aeruginosa/MEC System

Round 1

Reviewer 1 Report

This manuscript titled “Improvement of nitrous oxide recovery from incineration leachate through electrode material optimization in a ΔnosZ Pseudomonas aeruginosa/MEC system” is an interesting paper for the readers/researchers. This manuscript corresponds to the topic of the journal profile.

My critical remarks are below:

·      The title of the manuscript is very long. I consider it appropriate to reduce it without losing the sense of the investigation.

·       line 12 please add a space between oxide_(N2O)

·      line 13 I suggest you define the acronym MEC (microbial electrolysis cell) before using it in line 24.

·      Line 97-99 please add the contact surface area of each electrode.

·      Line 97-99 also specify the type of material with the electrodes were connected, for example copper, etc.   

·      Do you have scanning electron microscopy photographs to see the biofilms and adhesion of P. aeruginosa on the supports? please add in result and describe in methodology 

·      line 110 pls add geographic coordinates of the place where you obtained the raw material

·      the equation 1 and 2 they are not necessary, please make references to your article, there it is very well described (https://doi.org/10.1016/j.biortech.2021.125082)

·      line 134 Why were the samples for microbiological analysis collected on days 21 and 47? why not use 9 (end TRH9), 33 (end TRH 6) and 47 (end TRH 3) ?

·      Please add a previous physicochemical characterization of the raw material used, for example BOD, TS, STV, Color, turbidity, in addition to those mentioned as COD and NO2. This will allow us to have an adequate overview of the water used.

·      Please in figure 3 identify each one of the processes described. Example (a, b and c) and add in part c the error bars, to see if there is statistical difference.

·      add conclusion

Minor editing of English language required

Author Response

Reviewer 2: This manuscript titled “Improvement of nitrous oxide recovery from incineration leachate through electrode material optimization in a ΔnosZ Pseudomonas aeruginosa/MEC system” is an interesting paper for the readers/researchers. This manuscript corresponds to the topic of the journal profile.

My critical remarks are below:

• The title of the manuscript is very long. I consider it appropriate to reduce it without losing the sense of the investigation.

RE: We thank the reviewer for pointing this out, and we now revise the title as “Electrode Material Optimization of Nitrous Oxide Recovery from Incineration Leachate in a ΔnosZ Pseudomonas aeruginosa/MEC System”

• line 12 please add a space between oxide_(N2O)

RE: Done.

• line 13 I suggest you define the acronym MEC (microbial electrolysis cell) before using it in line 24.

RE: As suggested by the reviewer, we have added the definition. (Now Line 14)

• Line 97-99 please add the contact surface area of each electrode.

RE: We thank the reviewer for pointing this out. We now add this information in the manuscript. (Now Line 106-110)

• Line 97-99 also specify the type of material with the electrodes were connected, for example copper, etc.   

RE: As suggested by the reviewer, we now add this information in the manuscript. (Now Line 110-111)

• Do you have scanning electron microscopy photographs to see the biofilms and adhesion of P. aeruginosaon the supports? please add in result and describe in methodology 

RE: We are sorry that we don’t scan the electron microscopy photographs. To make sure the RNA transcription test of denitrification and phenazine synthesis could successfully completed, we consumed all of the experimental samples collected from electrodes. And the RNA transcription test needs the fastest extraction when denitrification or phenazine synthesis occurs at the appropriate moment. Therefore, we also could not scan the electron microscopy photographs first and then do the RNA transcription test.

We thank the reviewer for giving a helpful suggestion, and will take it into our future experiments.

• line 110 pls add geographic coordinates of the place where you obtained the raw material

RE: We apologize for making the confusing. In fact, the supplied fillers were formed in our lab by a laboratory scale MBBR. They were not obtained from any wastewater treatment plants.

We now add this information in the manuscript. (Now Line 119)

• the equation 1 and 2 they are not necessary, please make references to your article, there it is very well described (https://doi.org/10.1016/j.biortech.2021.125082)

RE: Done. (Line 141-144)

• line 134 Why were the samples for microbiological analysis collected on days 21 and 47? why not use 9 (end TRH9), 33 (end TRH 6) and 47 (end TRH 3) ?

RE: The major concern of this study is the sustainability of N₂O conversion which related to the stable operation of reactors. Therefore, we need a few days to monitor the performance of reactors, so that we can obtain the required samples in stable operation after adjusting the HRT. It is the reason that we collected the samples after adjusting HRT for 9-12 days, rather than right of the time when adjust HRT.

• Please add a previous physicochemical characterization of the raw material used, for example BOD, TS, STV, Color, turbidity, in addition to those mentioned as COD and NO2. This will allow us to have an adequate overview of the water used.

RE: As suggested by the reviewer, we now add the characterization of wastewater used in this study and summarized the information as Table 1. (Line 130-132)

• Please in figure 3 identify each one of the processes described. Example (a, b and c) and add in part c the error bars, to see if there is statistical difference.

RE: As suggested by the reviewer, we now reconstructed the Figure 3.

• add conclusion

RE: As suggested by the reviewer, we now add the Conclusion section. (Line 343-357)

Author Response File: Author Response.pdf

Reviewer 2 Report

Report on the manuscript fermentation-2433467 entitled “Improvement of nitrous oxide recovery from incineration leachate through electrode material optimization in a ΔnosZ Pseudomonas aeruginosa/MEC system”. This article can be recommended for publication, but after clarifying and detailing some parts of the text.

1.      The abstract section must be informative and should give more exact details about the purpose of the work in the introduction section. What are the new insights? The novelty of work must be elaborated.

2.      In short, “introduction” paragraph is too short, the authors may refer to further recent published research that are more relevant to this work.

3.      Full forms of many abbreviations are not given. All the abbreviations should start systematically with their full-forms.

4.      Authors must discuss most part of the results without bibliographic support! In many sections, references are needed. Recent literature needs to be updated. Please, by using similar papers that evidenced the same behavior, the Authors are encouraged to better describe the obtained results;

5.      All the figures need to be reconstructed. Hard to read captions of the figures. Tables format must match with journal style. Author must pay attention to journal templates.

6.      Conclusion is too short. In the conclusions, it is necessary to clearly formulate what new data about the studied factors were obtained in this work?

 

 

Moderate editing of English language required

Author Response

Reviewer 3: Report on the manuscript fermentation-2433467 entitled “Improvement of nitrous oxide recovery from incineration leachate through electrode material optimization in a ΔnosZ Pseudomonas aeruginosa/MEC system”. This article can be recommended for publication, but after clarifying and detailing some parts of the text.

 

1. The abstract section must be informative and should give more exact details about the purpose of the work in the introduction section. What are the new insights? The novelty of work must be elaborated.

RE: The new insights of this work are improving the N₂O recovery thorough electrode materials optimization in a ΔnosZ Pseudomonas aeruginosa/MEC system and exploring the optimization mechanism involving biomass, denitrification and electroactivity of ΔnosZ Pseudomonas aeruginosa.

As suggested by the reviewer, we now revised some sentences to make the abstract more informative (Line 13-16 and 22-23).

2. In short, “introduction” paragraph is too short, the authors may refer to further recent published research that are more relevant to this work.

RE: We thank the reviewer for providing this suggestion. Due to the innovative and multidisciplinary of our research, there are not many references relevant, but nevertheless we have added some references and enriched the content in the Introduction section. (Line 83-94)

3. Full forms of many abbreviations are not given. All the abbreviations should start systematically with their full-forms.

RE: As suggested by the reviewer, we check through the manuscript and add the full forms of abbreviations that we missed. (Line 145 and 183-184)

4. Authors must discuss most part of the results without bibliographic support! In many sections, references are needed. Recent literature needs to be updated. Please, by using similar papers that evidenced the same behavior, the Authors are encouraged to better describe the obtained results;

RE: We thank the reviewer for providing this suggestion, and understand the reviewer’s concern. Same as the Question 2, there are few studies similar to our work. We are sorry that we can’t find the papers have the same behavior to our study.

5. All the figures need to be reconstructed. Hard to read captions of the figures. Tables format must match with journal style. Author must pay attention to journal templates.

RE: As suggested by the reviewer, we have reconstructed all the figures and make the captions bigger to read. (Figure 1-6)

6. Conclusion is too short. In the conclusions, it is necessary to clearly formulate what new data about the studied factors were obtained in this work?

RE: As suggested by the reviewer, we add a section of Conclusion and highlight the new data which essential for N₂O recovery from wastewater in this work. (Line 343-357)

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors attended each of the indicated observations, it is a pity that they do not have scanning electron microscopy (SEM) photos, it is suggested to be added in future projects. The manuscript may be published in this form.

 Minor editing of english language required

Reviewer 2 Report

The author has successfully addressed all the comments. Moreover, author has made significant changes in the manuscript to fulfil the reviewer's requirement. I feel the revised manuscript is now well readable and eligible to be published in this journal.