Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz Constructed Wetland-Microbial Fuel Cell System

Round 1

Reviewer 1 Report

The topic “Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz CW-MFC System” might be new in some aspects. However, I have some comments that are:

 

1)      Pls try to reduce the abbreviation in the title

2)      What is the common name of Leersia hexandra Swartz? Better to incorporate in the abstract

3)      What do you mean by COD in the abstract?

4)      In Introduction, pls mention a few sentences about how Cr (VI) is reduced to Cr (III). What is the function of O2 in this process? How MFC enhance this process?  

5)      In MM section, I could not get any experimental location, duration, design treatments etc.

6)      In L#360, What do you mean by T?

7)      In conclusion, you simply mention results. It would be more interesting if the authors included the future research need related to this practice and/or how can implement this technique as a potential strategy to reduce Cr toxicity in other countries in the conclusion section.

 

8)      Pls reduce references 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

General comments

The manuscript "Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz CW-MFC System." analyzed the effect of an increasing dissolved oxygen concentration on the reduction ability of Cr (VI) in the Leersia hexandra, a constructed wetland (CW) and microbial fuel cell (MFC) system based on accumulation by L. hexandra, the contribution of microorganisms, and the physical adsorption and bioelectrochemical reduction. The results of this study are significant and can provide a reference for the CW-MFC treatment of Cr-containing wastewater under practical conditions.

The manuscript is interesting and well presented; however, the manuscript requires clarity, especially in section 5. Conclusion section. Particularly in lines 375-377: "This study showed that the DO concentration was 4.5 mg·L-1, the maximum voltage 375 of the system was 520 mV, the COD removal rate was 93.73%, and the Cr (VI) removal 376 rate was 97.77% when the aeration rate was 6 L·min-1." The authors must highlight the inference rather than reiterate the experimental results.

Additionally, the manuscript must be thoroughly formatted, as seen by numerous grammatical and typographical errors.

Therefore, I would recommend reconsidering the article after a minor revision.

Following, I have included a few minor comments:

Line 12: "Both the human body and the environment are hazardous to Cr (VI)." This sentence does not make sense. Cr (VI) is hazardous to humans and our environment. Please rewrite the sentence.

Lines 3, 13, 17, 53, 79, 124, 192: Abbreviations must be defined before their first usage

                 Line 3: “.. Swartz CW-MFC System.”: What is CW-MFC?

Line 13: "microbial fuel cell (CW-MFC) system to…..": What is CW-MFC?

Line 17: "the COD removal rate was….": What is COD?

Line 53: "O2 as an electron acceptor ….:. Should use oxygen instead of O2

Line 79: "The UPVC tube ..": What is UPVC?

Line 124: "….component is the SE2's second..": What is SE2?

Line 149: "The improved BCR continuous ….": What is BCR?

Line 192: "stabilized at 60 d.": Should be 60 days

Line 82: "activated carbon (20 cm, 10 cm).": 20 cm and 10 cm, respectively.

Line 91: The image quality of Figure 1 must be improved.

Line 140: ".. for 2 h, centrifuged …": Should be hr or hours

Lines 177-189: For clarity, figure 2 subsections must be referenced in the text. Additionally, the figure subsections must be reordered for clarity. For example, Figures 2(a) and 2(d) depict pristine activated carbon. Why not show Figures 2(a) and 2(b)? Similar issues with Figures 2(b) and 2(e) and Figures 2(c) and 2(f).

Line 203: The visualization of Figure 3 must be improved, and redundant markers must be removed from the plot.

Lines 286 and 295: In Figures 8 and 9, the microbial community composition font size must be increased for clarity.

 

Line 360: "T Current research increased the cathode …": Typographical error.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf