Comparative Study of Different Production Methods of Activated Carbon Cathodic Electrodes in Single Chamber MFC Treating Municipal Landfill Leachate

Round 1

Reviewer 1 Report

This manuscript introduced the leachate treatment through activated carbon ceramic-supported electrodes in a single-chamber microbial fuel cell. The topic of this study is interesting. But some parts still need to be improved. Here are some specific comments.
(1) The literature review needs to be more critical.
(2) Please provide more details about the testing system and methods.
(3) Please highlight the innovation of this study.
(4) The results and discussion are too brief. Please add more contents in this section.
(5) More details about statistical analysis in result analysis are required.
(6) Please compare the results in this study with those in previous studies.
(7) What are the major factors which affect this treatment process?

Author Response

We would like to thank our reviewers for carefully reading our submitted paper and for their useful comments and suggestions which have been taken into account in preparing the revised manuscript. The corresponding changes in the revised manuscript, are highlighted. We earnestly hope that the reviewers and the Editor will find the paper in its present form acceptable for publication.

Point-to-point answer to Reviewer 1:

This manuscript introduced the leachate treatment through activated carbon ceramic-supported electrodes in a single-chamber microbial fuel cell. The topic of this study is interesting. But some parts still need to be improved. Here are some specific comments.

1. The literature review needs to be more critical.

Thank you for your comment, we have enriched the literature review specifically in the introduction section.

2. Please provide more details about the testing system and methods.

More details are added in the materials and methods section, according to the reviewers, suggestion.

3. Please highlight the innovation of this study.

The introduction section is modified in order for the reader to understand the contribution of our work in the field.

4. The results and discussion are too brief. Please add more contents in this section.

The results and discussion section is enriched according to the reviewers’ suggestion.

5. More details about statistical analysis in result analysis are required.

Dear reviewer we are not sure what do you mean by “statistical analysis” .

6. Please compare the results in this study with those in previous studies.

Thank you for your comment. We understand what the reviewer means, but in this case it is difficult to compare the results with other studies for many reasons. For example, each lab has different cell designs/ materials, different wastes are treated, different acclimation procedures are followed. Previous studies which present activated carbon electrode preparation techniques are now added in the introduction section. We think that the comparison of the results with the different techniques under the same operation conditions of the MFC, it is the best way to be presented in this work.

7. What are the major factors which affect this treatment process?

Thank you for your question. The treatment process is affected by various factors such as design, materials, catalysts, cathodic electrodes, substrates etc. The introduction section has been modified explaining better the MFC technology and the major factors affecting its performance thus the treatment process.

Reviewer 2 Report

The description of the materials and methods used are really poor. It is necessary to compare the methods presented to produce cathodic electrodes with others methods presented in the bibliography. 

Also, it is necessary a description of the experiments carried out to define the COD removal, the variation in the conductivity and include other parameters as the variation of the ORP potencial, for example. 

In the text, there are some mistakes, for example two figure 7, in line 114 the reference of the Standard Methods in not clear, in figure 6, it is not cleat what line represent the Power and the Voltage, ....

Author Response

1. The description of the materials and methods used are really poor. It is necessary to compare the methods presented to produce cathodic electrodes with others methods presented in the bibliography. 

Dear reviewer, thank you for your comment. We have enriched the materials and methods section. We think that the comparison of the results with the different methods under the same operation conditions of the MFC, is the best way to be compared in this work. However, we presented other methods from previous studies in the introduction section.

2. Also, it is necessary a description of the experiments carried out to define the COD removal, the variation in the conductivity and include other parameters as the variation of the ORP potential, for example. 

We hope that the rewritten “materials and methods” section provide the necessary information for our experiments.

3. In the text, there are some mistakes, for example two figure 7, in line 114 the reference of the Standard Methods in not clear, in figure 6, it is not clear what line represent the Power and the Voltage, ....

All the manuscript has been carefully checked and rewritten, correcting the above (and not only) mistakes according to reviewers’ suggestion.

Reviewer 3 Report

The title focuses on the leachate treatment by MFC using active carbon ceramic-supported electrode. However, there are few investigation about the electrode characteristic, pollutant degradation, and biology.

In introduction, the research status of MFC needs to be added.

The English should be polished.

Author Response

1. The title focuses on the leachate treatment by MFC using active carbon ceramic-supported electrode. However, there are few investigation about the electrode characteristic, pollutant degradation, and biology.

Thank you for your comment we have modified the title.

2. In introduction, the research status of MFC needs to be added.

We have enriched the introduction section according to the reviewers suggestion.

3. The English should be polished.

All the manuscript has been carefully checked and rewritten where it was needed.

Round 2

Reviewer 2 Report

It is necessary to strengthen the conclusion with more datas. 

The articles had been rewritten but it is necessary to strengthen the conclusions with more datas. The COD removal of the different production methods are really similar taking account the high organic load of the leachate used. 

Author Response

The conclusion section is rewritten taking into account the reviewers’ comment. In particular the conclusions are enriched with more data from the results. Moreover, the COD values were added for all methods indicating and making clear, that it is high for all cases, although a slightly higher value was achieved with the SC technique. We thank our reviewer for indicating this and hope that now is written properly

Reviewer 3 Report

The manuscript was revised and ready for publication.

Author Response

We thank our reviewer for taking time to review our work