The Use of Constructed Wetland for Mitigating Nitrogen and Phosphorus from Agricultural Runoff: A Review

Round 1

Reviewer 1 Report

I believe that the review is correct and can be published. One aspect to improve is the bibliography since it does not have a homogeneous format.

Author Response

Thank reviewer for the recommendation of our work. Following the suggestion, we have checked and revised the format of the bibliography. Please see the changes highlighted in red in the bibliography.

Reviewer 2 Report

There are only two typos:

Line 128: Please change to "The above review..."

Line 168: Please change to "In addition to single plant species,..."

 

Overall, the manuscript is now suitable for publication. 

Author Response

Thank for the reviewer’s careful review and detailed suggestions. Apologies for the errors. We have corrected the two typos. The specific changes are highlighted in red in Lines 123 and 163 in the revised manuscript.

Reviewer 3 Report

The authors presented a review on the treatment capacity of optimum substrates and plant species for the mitigation of nitrogen and phosphorus from agricultural runoff. This manuscript shows an organized work, the results from the available literature being described, but some aspects must be improved before recommending its publication in Water.

 

Please write the full name of chemical elements in the sections and sub-sections’ titles (nitrogen and phosphorus).

I suggest to eliminate the split of section 1 in three sub-sections. It is easier to follow only one section undivided.

I suggest to revise the phrase at line 138 to increase the readability.

Please add “.” after “sp” in Table 2.

The English language should be revised throughout the manuscript using a native speaker.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments to manuscript water-927160 entitled “The use of constructed wetland for mitigation of algal blooms from agricultural runoff: A review”

 

This review treats an important topic. Algal blooms, especially the toxic ones are endangering natural ecosystems, decrease the quality of recreational and irrigation of water and have potential effects on human health by threatening reservoirs used for the production of drinking water.

The work is comprehensive enough. However, its title suggests the authors will concentrate more on the direct elimination methods of algal blooms. Instead, not much of this aspect is treated (only the Introduction section contains a brief overview of this) and the Authors concentrate mainly on the elimination of N and P- which of course influence algal proliferation, so this is an indirect method for mitigating algal blooms. I would like to see studies on exactly how the decrease of N and P concentrations lead to mitigation of blooming?

 

“2. Methods” section- I think this should be omitted, since the Authors just enumerate common methods of preparing a review article.

 

Minor comments are included in the annotated manuscript.

 

To conclude, I suggest a major restructuring of the paper.

Comments for author File: Comments.pdf

Reviewer 2 Report

The Authors conducted quite an extensive survey of literature, however the resulting paper needs far more work, to reveal the full value of their efforts. The main points to consider are listed below.

1. The title of the paper is somewhat misleading. Instead of concentrating on the presentation of research on the reduction of algal blooms in natural water bodies impacted by agricultural run-off or wastewater discharge, the Authors devote most of the paper to discussing the reduction of N and P load without showing how such a reduction impacts the development of algae. They should have elaborated on what is presented in Table 1.

2. English of the paper calls for thorough revision. The paper is difficult to read, and some fragments are confusing due to clumsy language.

3. ll. 46-48: Impressed by the upsurge in nitrogen retention in agricultural systems, the Authors seem to neglect the role of phosphorus, which — as far as algal blooms are concerned – still remains strong limiting factor, especially for the cyanobacteria capable of utilising atmospheric N.

4. ll. 57/58: During photosynthesis algae release oxygen in amounts exceeding their respiration needs. Writing about oxygen loss caused by algae, the Authors should be more specific, and state that what they refer to is the decay of excessive algal biomass produced during a bloom.

5. ll. 85 ff.: The description of methods should be more precise. In particular replies to the following questions would be useful:

   1. How come that out of over 2000 hits only 112 (less than 6%) were found appropriate for the paper?

   2. How were the keywords used: separately, all together, in groups?

      1. If not separately: how were they connected in a search engine?

   3. Methods of “qualitative comparison” and “quantitative comparison” should be described, or references should be provided.

6. l. 122 and elsewhere in the paper: the term “denitrification” is used improperly. Actually, denitrification is a microbial process where nitrate (NO₃⁻) is reduced to molecular nitrogen (N₂).

7. l. 184: Taking into account that the Authors surveyed over 2000 papers, 15 is not an impressive number. An explanation/discussion would be handy.

8. Table 1:

   1. There is no need to repeat “technologies” so many times, putting it once in the heading is sufficient.

   2. Second column is badly formatted, hence difficult to follow.

   3. Third column should be divided into two: one for advantages, second for disadvantages.

   4. The last column should be re-formatted in such a way that references correspond to the techniques they describe/discuss.

9. Table 2:

   1. Second column should be divided into two: one for advantages, second for disadvantages.

   2. Only one reference per substratum type does not look impressive.

10. Table 3:

    1. The layout should be reconsidered. The table should be arranged around species, not around countries.

    2. l. 187: No statistics was calculated, so the term “statistical frequency” is not justified. Frequency without adjective would be better visible if the table was rearranged.

Other points have been marked directly on the manuscript

Comments for author File: Comments.pdf

Reviewer 3 Report

The authors presented a review on the treatment capacity of optimum substrates and plant species for mitigation of algal blooms from agricultural runoff. This manuscript shows a well-organized work, the results from the available literature being comprehensively described, but some aspects must be improved before recommending its publication in Water. Please write the name of all plants in italics (some were missed in the abstract). Please summarize the importance of this review at the end of the abstract and of the manuscript. I suggest to write in italics the words “Merits” and “Demerits” within the Table 1 in order to better highlight them. It is confusing as the paper is a review, but it is presented in the form of a research paper with chapters such as “Methods”, “Results and discussion”. I suggest to find a better organization of the chapters for this review. The English language should be revised throughout the manuscript. Please remove “.” at lines 102 and 331.