Nutrient Removal in Sequential Batch Polishing Ponds

Round 1

Reviewer 1 Report

I was delighted to have the opportunity to review this paper, and I was not disappointed when I read it.

 

It is a logical and rigorous pursuit of a new relatively little studied variation on a very widely used, but frequently overlooked wastewater treatment technology. The paper starts simply and builds to if not a crescendo at least a very pleasing and practical conclusion.

 

I do have a few criticisms

 

• The manuscript has a few typos and cosmetic problems and sometimes the occasional Portuguese word creeps in. However, these are easily fixed and did not affect my ability to review the manuscript,

 

• Moreover, the authors may have overstated the deficiencies of conventional wsp and perhaps overlooked some of the practical issues associated with running a batch system.

 

• The bulk of the findings are actually in the section labelled “discussion”. It might be simpler to have a results and discussion section.

 

I have a few more detailed comments.

 

Line 54  The authors may recall that Pearson and Mara proposed something similar (Water Science and Technology Volume 33, Issue 7, 1996, Pages 251-260) and it likely that there would be excellent pathogen removal in the propose reactors.

 

Line 74 “nitrifying sludge”  It might be better to say nitrifying biomass

 

Figure 2. If these are average values, is it possible to show the standard deviations? Also please make clear that H is depth.

 

Line 169.. The discussion contains a lot of results!

 

Line 197 This paragraph (beginning the authors should) does not really make sense and can be deleted.

 

Line 232 “O PH” = “the pH”

Line 261  “1a e 1b” = “1a and 1b”

Line 321  “OD” should be DO?

Author Response

The answers to the reviewer are attached

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript "Nutrient removal in sequential batch polishing ponds" describes the results of pilot tests on municipal wastewater after an anaerobic treatment performed in a UASB reactor.

Please improve the English language.

The manuscript presents a key weak point: what is its novelty compared to the state-of-the-art literature? Biological processes related to nutrients' removal and the CO₂/Carbonates system have been extensively studied. Also the modelling section lacks originality.

The abstract is vague and needs to be rewritten and structured according to the conventional outline "problem statement, context and significance, methodology and approach, results (with quantitative data), conclusions".

please substitute "sewage" (lines 9, 110, 175 and throughout the text) with wastewater.

line 28: "theses"?

lines 35-37: no need to repeat twice the same concept. please synthesise.

lines 149-150: please add reference to this statement. 

Author Response

The answers to the reviewer are attached

Author Response File: Author Response.docx

Reviewer 3 Report

Abstract:

The objective of the study should be clearly underlined in the abstract. Abstract should also contain the scope of research.

 

Introduction:

All abbreviations must be explained the first time they are used, incl. WSP, CO₂. It should be verified in all text.

The structure of this section should be verified by authors. Please be aware that the scientific papers have the common structure, and each section should follow the requirements. This Introduction should be rewritten, according to the structure which should be included in the research papers. The introduction of a research paper should contain background of the study, followed by identification of research gap, and proposed solution to fulfil this gap, supported by objectives of the research, and scope of paper.

Please provide the context of novelty in this research.

There are some grammatical errors. This should be verified in the text.

 

Materials and Methods:

Well-described.

I suggest to change “Figure 1 is a flow sheet…” to “Figure 1 shows a flow sheet..”. Please try to indicate this 2-parts Figure on one page of the manuscript.

 

3. Results:

Please try to describe the results without this bullets, and giving a detailed description.

 

4. Discussion:

The procedure to calculate the curve (with eqs. In the text and Table 2) should be a part of the section “Materials and Methods”

This basic eqs are unnecessary:

Photosynthesis: CO2 + H2O à MO + O2 (7a)

Oxidation: MO + O2 à CO2 + H2O

Please revise this part of the manuscript. There is a lot of text which should be moved to the section “Materials and Methods” instead of Discussion.

There is lack of deed discussion, and comparison with other authors.

 

5.Conclusions:

Please provide the conclusions, not repetition of the results.

 

References:

Should be adapted to journal template.

Author Response

The answers to the reviewer are attached

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

the Authors improved the manuscript according to the comments and recommendations. A revision of the English is recommended, the Authors committed to address the issue through MDPI.

Author Response

English language changes will be made if accepted

Reviewer 3 Report

Authors did not take into account all of my comments. 

There are lack of real conclusions, but just the repetition of the results. Authors underline that they as the first developed solution "first paper that discusses sequential batch polishing pond, so there is nothing to refer to or compare with". How the results can be used by other scientists? What are the limitation of these results?

Author Response

See attached file. 

Author Response File: Author Response.docx