Potential of Canna indica in Constructed Wetlands for Wastewater Treatment: A Review

Round 1

Reviewer 1 Report

 

There are some comments available in PDF file.

Comments for author File: Comments.pdf

Author Response

I thank you for the comments.

I worked on the document and made the modifications according to the comments. This includes correction of intext citing, sentences rephrasing, and proper measurement units writting.

I removed some tables and the related information are put in text. Some recent referenced have been added, resulting into change of the manuscript structure, length of the manuscript and increase in number of references.

I once again thank you for the comments

Author Response File: Author Response.pdf

Reviewer 2 Report

I have no critical comments. Nicely prepared review article.

Only from the point of view of a central European, where we don't have such a favourable climate :-) it might be good to add information for which climate zone is suitable Canna indicafor use in CW systems.

Author Response

Response to Reviewer 2 Comments

 

Point 1: I have no critical comments. Nicely prepared review article.

 

Response 1: Thank you

 

Point 2: Only from the point of view of a central European, where we don't have such a favourable climate :-) it might be good to add information for which climate zone is suitable Canna indicafor use in CW systems.

 

Response 2: Regarding favourable climate, the plant is native to tropical regions of America, and now available in different countries around the world. The plant can survive in different light conditions and can grow well in both dry and marginal soils. These information have been added in the document References 31, 32 and 33.

Author Response File: Author Response.pdf

Reviewer 3 Report

General Comments:

The topic of this manuscript is scientifically worth reviewing. However, this review paper contains limited information and appears to be simple. Growth characteristics, favourable growth conditions, organic and inorganic loadings that can withstand, lifetime and suitability for diverse seasonal/geographical variations of this species are not discussed. Particular design criteria and configurations of CW that utilize Canna are the crucial aspects and they are not adequately discussed here in this review. There are more recent papers on this subject (with different wastewater characteristics and CW configurations) that could have been referenced here. I believe this review paper is not comprehensive enough to consider for publication at this state and requires major revisions.

 

Specific Comments:

 

L138	“substate” should be “substrate”
L160-174; L203-227	This content has minor relevance to the main topic. Could have been made it concise and shifted to the introduction section
L 96	Details of the design and possible configurations for CW should have been included. Resistance of this species to seasonal and geographical variations, organic loading and inorganic loadings that can withstand should be discussed.
L247;	Limitations/drawbacks/challenges of this species are not discussed.

Comments for author File: Comments.pdf

Author Response

Thank you for the comments which made a major part of the manuscript revision.

Conditions regarding favourable characteristics and growth conditions of Canna indica have been added to the document. References 30, 31 and 32.

Some recent papers have been added and cited in the document. Inclusion of this document has resulted into modification of the document structure, length of the paper and number of references.

The content introducing heavy metals was added in a specific section because particular information is specific to heavy metals only

Designing is a critical aspect in the performance of CW. The CW configurations used in the reviewed papers are included in Table 1 (The first column). Explanation on the most used type of CW with Canna indica is given in Line 172 to 176

Information on the effects of the contaminants on the plant have been added in the document. LIne 423 to 428

The major challege given is the emission of greenhouse gases. This has been a a general drawback of constructed wetlands but on comparison to other wetland plants studied, Canna indica emitts less nitrous oxide, carbon dioxide and methane. This section is added in the document. Line 441 to 444

Author Response File: Author Response.pdf

Reviewer 4 Report

1.     In table 1, the removal efficiency of COD, BOD and others are conducted by VSSFCW, not juts by Canna indica, but the paper is focused on the performance of Canna indica, so, the table should be revised also the related references.

2.     The same question as question 1 in table 3.

3.     The review just describes the related references and had no discuss or experimental results of the author, it is more likely a reading note.

4.     For a review, this paper is too short and has no meaningful information.

Author Response

Thank you for the comments

1. Table 1 bas been revised. Instead of writing Performance of Canna indica, it is written performance of CW planted with Canna indica.
2. Table 2 and Table 3 have been removed. The related information have been have been punt into text. Some more information have been added in the document including the recent papers. This has improved the structure and length of the manuscript.
3. This work has no experimental results from the author. It is a review of the available information regarding the use of Canna indica in constructed wetland

Author Response File: Author Response.pdf

Reviewer 5 Report

The review article is concerned with investigating Canna indica, which is utilized in constructed wetlands (CW) for wastewater treatment of a variety of types. Plants play important roles in CWs by giving the conditions for physical filtration of wastewater, a large specific surface area for microbial growth, and a source of carbohydrates for bacteria. They absorb nutrients and integrate them into plant tissues. They release oxygen into the substrate, establishing a zone in which aerobic microorganisms can thrive and chemical oxidation can occur. Canna indica's effectiveness in CWs has shown encouraging results for eliminating contaminants from wastewater. There is still a scarcity of information on the removal of specific emerging contaminants such as pharmaceuticals, personal care products, hormones, pesticides, and steroids. It is suggested that the paper is short so please include more information available about emerging contaminants. The paper covers some important issues but some points should be corrected. I recommend the manuscript for publication in this Journal after major revision.

Some comments are listed below:

1.       In Title, I would like to suggest; Potential of Canna indica in Constructed Wetlands for  Wastewater treatment: A review

2.       Please check the reference styles that were cited in the whole manuscript.

3.        It is suggested that the authors should give a brief description of Canna Indica name and region (in the 5^th paragraph Introduction section)

4.       Please note the upper case and lower case in the entire manuscript.

5.       The English language of the paper should be improved.

6.       I strongly suggested that please add some more literature because the manuscript is too short regarding the removal of pollutants via Canna indica in constructed wetlands (such as putting a portion of removal of organic contaminants)

 

 

Comments for author File: Comments.pdf

Author Response

Thank you for the comments.

1. In Title, I would like to suggest; Potential of Canna indica in Constructed Wetlands for  Wastewater treatment: A review

The comment has been adopted in the document

2. Please check the reference styles that were cited in the whole manuscript.

The references and intext citing has been checked and corrected accordingly

3. It is suggested that the authors should give a brief description of Canna Indica name and region (in the 5^th paragraph Introduction section)

A description of the plant has been added in the document

4. Please note the upper case and lower case in the entire manuscript.

The upper and lowe case has been checked and corrected

5. The English language of the paper should be improved.

I am wrking on this

6. I strongly suggested that please add some more literature because the manuscript is too short regarding the removal of pollutants via Canna indica in constructed wetlands (such as putting a portion of removal of organic contaminants)

Some recent papers have been included in the document. This has modified the structure of the document including length of the manuscript and number of references to 112. More sections have been added

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

It is good you have edited the paper. However I would suggest you to incorporate few reference more such as:

1. Wetlands Ecology and Management volume 30, pages35–45 (2022)

2. International J or Phytoremediation Volume 17, 2015 - Issue 10, Pg 999-1004

3. International Journal for Research in Applied Science & Engineering Technology (IJRASET) Volume 8 Issue VIII Aug 2020, Pg 1190-1193

Or add some more literature such as for Grey Water Treatment, or low strength BOD wastewater.

 

Author Response

Thank yo again for the comments and recommendation of the papers to be added in my manuscript. I now respond on the papers you recommended;

1.Wetlands Ecology and Management volume 30, pages35–45 (2022)

This paper was already cited in the document. So no changes have been made. Line 365, Reference no 120

2.International J or Phytoremediation Volume 17, 2015 - Issue 10, Pg 999-1004

The paper has been added in the document. Reference no 55

3. International Journal for Research in Applied Science & Engineering Technology (IJRASET) Volume 8 Issue VIII Aug 2020, Pg 1190-1193

The paper has been added in the document. Reference no 56

Thank you again for your time

Author Response File: Author Response.pdf

Reviewer 3 Report

Thank you for submitting a revised version. 

However, Not much improvement has done to the revised version. Even though very few details are added regarding plant growth requirements, they appear to be qualitative and vague. 

Even though more discussions are added on contaminant removal, it appears to me that the information is still the same. The only difference is that previously tabulated information is now given in paragraphs. 

Details of the design configuration of CW that utilises Canna, tolerable limits of certain contaminants, and quantitative details on lifetime, life cycle, and growth performance are still missing. 

Author Response

Thank you once again for your time and valuable comments on my manuscript. I made some revisions based on your comments. My responce on the comments are as follows

1.Few details  regarding plant growth requirements

A new table has been added in the document which summarises the description of the plant. (Table 1 in the current version)

2.Even though more discussions are added on contaminant removal, it appears to me that the information is still the same.

In removal of pollutants, more details were added. This includes new sections subsections and references. The changes made may be tracked in the first revised manuscript and the current version

3. Details of the design configuration of CW that utilises Canna, tolerable limits of certain contaminants, and quantitative details on lifetime, life cycle, and growth performance are still missing. 

In table 2, i added colums for the information of the type of constructed wetland and the substrate used. The information Plant description, Botanical classification, Habitat and geographical distribution, Tolerance and Uses age given in Table 1.

Thank you again for your time

 

Author Response File: Author Response.pdf

Reviewer 4 Report

The author had revised the paper, but the revision was not convinced me to accept. The reaction mechanism was necessary not just described the related works.

Author Response

Thank you for your time and comment comment. I am responding to the comment you made on my manuscript.

Comment: The author had revised the paper, but the revision was not convinced me to accept. The reaction mechanism was necessary not just described the related works.

Responce: The mechanisms of removal of different types of pollutants have been given in the manuscript depending on the papers cited. This is a review manuscript which means i report the mechanisms already reported by other authors. For instance Line 210-217, line 306-308 and line 359-364 inthe current version describes the mechanisms used to remove the pollutants.

I am ready to modify more.

Thank you again

 

Author Response File: Author Response.pdf

Reviewer 5 Report

Accept in present form

Author Response

Thank you for the comment

Round 3

Reviewer 3 Report

The author has addressed previous comments adequately. The current version could be considered for publication. 

Author Response

Dear reviewer,

I thank you for your contribution

Reviewer 4 Report

Review is not only just describing other research's works, but also introduce some new aspects or findings of the author yourself. The key points are the author's idea, comments and findings.

Author Response

Dear reviewer,

Thank you again for your time and constructive comments on my manuscript. It gives me opportunity to learn more and more. Based on your comment, i added some information which are basically my findings or my comments on the reviwed information. The added information are as follows,

Line 136-140: A need for comparison study on performance of different designs of constructed wetlands planted with Canna indica.

Line 154-157: A need of investigating how Canna indica will perform in combination with different plant species while plant density, plant mixing, and the number of plant species in each configuration are considered.

Line 171 - 173: Because an operating constructed wetland needs harvesting of the plants to allow good performance, we found a scarcity of information about Canna indica harvesting in CWs. More research is needed to determine the ideal time and technique of harvesting that does not compromise the CW's performance.

LIne 196-200: In areas where water have high concentration of Fluoride like Arusha, Tanzania, there are researches intending to remove it using different methods. More studies employing Canna indica are required in connection with ongoing researches on the removal of fluoride from surface water and wastewater. Pilot study is required to incorporate more realistic conditions, such as actual wastewater spiked with known fluoride concentrations. Further research should be done to determine how fluoride as a pollutant affects Canna indica in the CW.

Line 325-330: All the pesticides discussed belongs to two groups such as organophosphates and organochlorides. More research is needed to investigate the potential of CW planted with Canna indica to remove more pesticide groups such as carbamates, fungicides, and herbicides under diverse environmental circumstances. This would contribute to the design of CW systems for pesticides contaminated wastewater treatment.

Line 368-372: These findings, however, reveal the need for more study incorporating diverse classes of pharmaceuticals, as the ones discussed are antibiotics. Because of the complex mixture of pharmaceuticals in hospital wastewater, for example, more study incorporating a large mixture of contaminants is needed in the future.

LIne 387-292: The provided information is based on one industrial chemical. With increased industrial activity comes an increase in pollutant discharge, which will undoubtedly have an effect on the ecology. The chemical composition of industrial wastewater varies greatly depending on the industry, such as paint and dye processing, textile, pharmaceutical, paper, and fine chemical manufacturing. This means that more research on industrial chemical removal in Canna indica-planted CW is needed.

Thank you again for your time.

Author Response File: Author Response.pdf