Performance Evaluation of Diverse Filter Media Combinations Under Different Pollution and Hydraulic Loads in Constructed Wetlands

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. Add some experimental data in abstract section which is completely missing.
2. Why specific filtermedia such as bio-ceramsite, volcanic, and quartz sandhave been used in constructed wetland?
3. Add few real images of experimental setup along with components to the manuscript.
4. Give details constituents (in mg/L) of synthetic sewage in Table format in the manuscript.
5. What is the significance of doing SEM of filter media? What it implies?
6. Mention the novelty of the current study.
7. Authors could have set few more set-up with plants along with media for further comparision.
8. The discussion on microbial mechanisms is insightful; however, linking these findings more directly to system design implications would strengthen the paper.
9. Plz cite more recent studies on CW filter media performance.
10. Manuscript required english correction.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article thoroughly investigates the effectiveness of bio-expanded clay, volcanic and quartz sand and their combinations in treating synthetic wastewater. The article is well written, but I recommend making some corrections before publishing it:

1. Introduction:

Although the authors emphasize in the introduction that “the conclusions might serve as a scientific basis and technical support for the application of constructed wetlands in environmental conservation”, the scientific novelty of their research is not highlighted. I recommend emphasizing more what scientific insights are presented in this article.

2. Methods and materials:

The duration of the experiments described in this section is unclear, and it is unclear whether the experiments were repeated. It is recommended that the authors explain how long it took for bacteria to grow in the filter media? If individual experiments lasted only a month and artificial wastewater was not filtered, then how did the colonies of microorganisms manage to grow? Where did the microorganisms come from in the filters?

3. Results and discussion:
   • In columns A3, B2 and B3, the pH of wastewater increased significantly to approximately 10.21. In the authors' opinion, can such wastewater be discharged into the natural environment? It is recommended to explain whether such results would meet the requirements for treating real wastewater.
   • The entries in Figures 4, 5 and 8 are too small and not visible.
   • From Figure 5, it is not clear in which filter media samples a), b) and c) were found.
   • The scientific discussion is only in section 3.1, there is no further discussion (pages 8-14).
   • It is recommended to continue the scientific discussion in sections 3.2, 3.3 and 3.4 and highlight the novelty of the study.
   • The pollutant removal efficiency obtained in this study is not very high for removing COD, TN and TP. It is recommended to highlight more advantages of this method (inexpensive and non-polluting materials, their reuse or utilization).
   • It is recommended to provide insights into whether the main results would change when treating real wastewater. What would be the role of microorganisms present in wastewater?

Conclusions:

There is a lack of general insights into the scientific novelty of the study.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The article has been properly revised, and all reviewer comments have been responded to.