Microalgal Growth and Nutrient Removal Efficiency in Non-Sterilised Primary Domestic Wastewater

Round 1

Reviewer 1 Report

The Manuscript ID: sustainability-2273688 “Microalgal growth and nutrient removal efficiency in non-sterilised primary domestic wastewater” requires revision before accepted for publication. The specific comments are given below.

1.     In the abstract, present the most important numerical results.

2.     The "Introduction" section should follow the state of the art of this field and review what has been done, for supporting the research gap and the significance of this study. Please improve the state of the art overview, to clearly show the progress beyond the state of the art.

3.     In the last paragraph of the introduction, clearly indicate the research hypothesis.

4.     Provide significant words which are more relevant to the work in a logical sequence as ‘keywords’.

5.     Please indicate the manufacturer, city, country when mentioning the equipment.

6.     The results of the obtained studies are very poorly described. Describe and interpret them and compare them with the results of other authors.

7.     It is also recommended to discuss and explain what should be the appropriate policies based on the findings of this study.

8.     In Conclusions chapter indicate the most important results of your research, problems and directions for the future.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments on sustainability-2273688 entitled “Microalgal growth and nutrient removal efficiency in non-sterilised primary domestic wastewater”

 

This manuscript presents a study devoted to actual problem dealing with domestic wastewater treatment using some species of microalgae. Microalgae cultivation at different levels of pollution by domestic wastewater, growth determination of these organisms, nutrient removal analysis and statistical methods were used in the work. The results are interesting and well-presented, and allow to improving domestic wastewater treatment primarily from nitrogen and phosphorus. I have some suggestions for improving this manuscript.

 

1) The authors point out, that strains of microalgae from the UTEX collection were used in the study (lines 94-95). However, the strains numbers are absent. Was a polyphasic approach, including molecular genetic methods, used to determine the taxonomic position of strains? This is important for the reproducibility of experiments with other strains of these species in the future.

2) Lines 225, 239, 246, 247, 257, 270, 286: “H. pluviaris” should be corrected to “H. pluvialis”.

3) Line 315, Appendix A: poor photo quality. There is no detailed description of microscopic methods in the Materials and Methods. If the authors used photographs from literature data, a link should be provided.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

 The present studies aimed to evaluate the growth of Scenedesmus sp., Chlorococcum aquaticum, Ankistrodesmus augustus and Haematococcus pluvialis in non-sterilised domestic wastewater and their potential of pollutants removal in wastewater. The microalgae were cultivated in different concentrations of non-sterilised domestic wastewater collected from primary wastewater plant of a national sewerage company in Malaysia. Each species’ capacity for growth and the removal of pollutants were assessed. The result showed that these microalgae can successfully remove nitrogen, ammonium, and phosphorus and reach the concentration limits set by Department of the Environment Malaysia. Among the tested microalgae species, Scenedesmus sp. had the highest capabilities at utilizing non-sterilized 100% wastewater as a growth medium and removing pollutants from wastewater because of its high growth and nutrient removal efficiency.

Overall, it is interesting to work and may be considered after some revisions.

"In many studies, the wastewater was sterilised before microalgae cultiva- tion to eliminate the microorganisms." needs citation.

"Among the microalgae species"....change to "Among the microalgal species"..

Please add the microbiological profile of wastewater.

Please add the growth kinetics of microalgal species to support your conclusions.

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

The authors investigated nutrient removal efficiency using microalgal to safeguard public health. The appropriate studies are always welcome in human needs. Some important points are important to be addressed before going to consider the possible publication in this journal.

 

-The English language needs to check carefully in the revision stage because of many careless mistakes in many positions.

 

-The Figure’s quality needs to be improved in the revision stage.

 

-References: There are many references that are not adjacent to this study. The authors need to take notes in the revision stage and cite relevant references including high-impact journals as defined by the Awual group to make the manuscript to a broad range of readers.

 

-Abstract: This section needs to be improved by presenting novel findings such as investigating the solution acidity, and the main experimental works in the revision stage.

 

-Introduction: Diverse studies are growing attention for diverse uses as reported by the Awual group according to ScienceDirect. The authors need to indicate such points for a broad range of readers. Moreover, the authors need to cite high-impact articles to make the manuscript high-level. The following specific articles may take be noted in the revision stage of Journal of Molecular Structure, 1282 (2023) 135259; Journal of Cleaner Production, 228 (2019) 1311–1319; Journal of Molecular Liquids, 336 (2021) 116325.

 

-Scientists considered the composite based on sensitivity, cost-effectiveness, and so on. The authors need to indicate such a point in the revised manuscript.

 

-The characterization is not accurate. The morphology needs to be added and then compared with reported materials as reported by the Awual group for a broad range of reader understanding.

I would like to see the revised manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf