Anaerobic Bioremediation of Acid Mine Drainage Using Sulphate-Reducing Bacteria: Current Status, Challenges, and Future Directions
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsI have reviewed the review the manuscript. It provides a comprehensive review of biological sulphate reduction as a treatment for acid mine drainage (AMD) and highlights its potential benefits and challenges. The topic is highly relevant to environmental sustainability and mining wastewater treatment. Below are some suggestions for improvement to enhance the clarity, structure, and scientific impact of the work.
The manuscript contains grammatical errors and awkward sentence structures, making some sections difficult to read. Some sentences are overly complex or repetitive, particularly in the introduction and discussion.
The introduction lacks a clear research gap and objective statement. While it provides background on AMD and its environmental impact, it does not explicitly define the scope of the review or how it differs from previous studies. The results and discussion sections are not well distinguished. Some information appears repetitive between these sections.
The methodology of the review is not well-defined. The paper presents findings from different studies but does not describe how sources were selected, inclusion/exclusion criteria, or the literature search strategy. Some key findings lack proper comparison with existing literature. While the paper discusses SRB-based AMD treatment, it does not clearly contrast findings with other remediation methods.
Some figures lack detailed captions and references, making them difficult to interpret.
The tables present valuable data but are inconsistent in formatting.
Some references are outdated or missing key recent studies on SRB-based bioremediation.
The paper highlights the challenges of SRB bioremediation, but the discussion on potential solutions and technological innovations is limited.
The economic feasibility of SRB-based bioremediation is not discussed in depth.
The manuscript contains numerous grammatical errors and awkward phrasing, affecting clarity.
Certain sections are difficult to follow due to long, complex sentences and poor transitions.
Author Response
Firstly, I would like to express my gratitude to the journal for the opportunity to revise and resubmit our manuscript for potential publication. We sincerely appreciate the time and effort invested by the reviewers in evaluating our work and providing constructive feedback. We have carefully considered all comments and incorporated revisions to address them comprehensively. Below, we outline the specific modifications made in response to the reviewers’ recommendations
Comment 1: I have reviewed the review the manuscript. It provides a comprehensive review of biological sulphate reduction as a treatment for acid mine drainage (AMD) and highlights its potential benefits and challenges. The topic is highly relevant to environmental sustainability and mining wastewater treatment. Below are some suggestions for improvement to enhance the clarity, structure, and scientific impact of the work. The manuscript contains grammatical errors and awkward sentence structures, making some sections difficult to read. Some sentences are overly complex or repetitive, particularly in the introduction and discussion.
Response: The necessary grammatical and structural adjustment have been made. Repetition was fixed and some of the words were simplified.
Comment 2: The methodology of the review is not well-defined. The paper presents findings from different studies but does not describe how sources were selected, inclusion/exclusion criteria, or the literature search strategy. Some key findings lack proper comparison with existing literature. While the paper discusses SRB-based AMD treatment, it does not clearly contrast findings with other remediation methods.
Response 2: The review now gives detailed information on how source or literature was selected (inclusion/exclusion criteria) [See page 1], and comparative analysis of SRB-based bioremediation methods against conventional treatment strategies [See page 7].
Comment 3: Some figures lack detailed captions and references, making them difficult to interpret.
Response: The captions of the figures were changed, and figures that were difficult to interpret were simplified by drawing them again.
Comment 4: The tables present valuable data but are inconsistent in formatting.
Response: The format of the tables has been kept constant throughout the paper.
Comment 5: Some references are outdated or missing key recent studies on SRB-based bioremediation.
Response: The literatures we sourced are directly related to the subject of the review and we now prioritized the latest research, typically within the last 5 to 10 years.
Comment 6: The paper highlights the challenges of SRB bioremediation, but the discussion on potential solutions and technological innovations is limited. The economic feasibility of SRB-based bioremediation is not discussed in depth.
Response: The discussion has been rewritten with detailed information on potential solutions and technological innovations [See page 18 and 19]. Also, the economic feasibility of SRB-based bioremediation is discussed in depth in page 19.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript provides a comprehensive review of anaerobic bioremediation of acid mine drainage (AMD) using sulphate-reducing bacteria (SRB). The topic is relevant to sustainability and environmental management. The authors have presented an extensive overview of the current status, challenges, and future directions of SRB-mediated bioremediation, including a critical analysis of various bioreactor designs and bioremediation strategies.
However, there are several aspects that require attention to enhance the clarity, scientific rigor, and overall quality of the manuscript. Below are specific comments and suggestions for improvement.
1-The abstract adequately summarizes the purpose, key findings, and future directions. However, it would benefit from including specific quantitative results or examples to strengthen its impact.
2-Consider rephrasing: "offers a promising solution by reducing of sulphates to sulphides" to "offers a promising solution by facilitating the reduction of sulphates to sulphides."
3-The introduction effectively sets the stage for the study. However, the transition from general environmental pollution to the specific issue of AMD could be more seamless. Consider restructuring the introduction to lead more naturally into the focus on SRB and AMD.
4- A few statements are too general. For example, "Pollution... significantly impacts air, water, and soil." Providing specific examples or statistics would add more weight to these statements.
5- The manuscript presents a thorough review of existing bioremediation technologies. However, some sections are overly descriptive and could benefit from a more critical evaluation of the methodologies and findings of the cited studies.
6- The review of bioreactor designs is detailed, but the manuscript could be strengthened by providing a comparative analysis of their efficiencies under different conditions.
7- The methodology described for evaluating bioremediation techniques is not fully clear. It would be helpful if the authors could provide a clearer framework or criteria for assessing the success of the bioremediation methods discussed.
8- The tables provided (e.g., Table 1 and Table 4) contain valuable information. However, Table 1 could benefit from reorganization to improve readability. Consider grouping similar variables together or using color coding to highlight trends.
9- Figures 1 and 2 are informative but could be enhanced with higher resolution and clearer labels.
10- The discussion provides a balanced view of the advantages and limitations of SRB-based bioremediation. However, it lacks depth in discussing the potential environmental risks associated with the use of SRB, particularly regarding the production of hydrogen sulphide.
11- The manuscript mentions genetic engineering of SRB as a future direction but does not explore this idea sufficiently. Including potential genetic modifications or examples from recent studies could enrich this section.
12- The conclusion effectively summarizes the findings but could be more impactful by directly linking the key insights to practical applications in environmental management. Suggestion: "Future research must concentration on enhancing bioreactor designs..." should be corrected to "Future research must focus on enhancing bioreactor designs..."
13- Some references are not consistently formatted. Ensure compliance with the journal's reference style.
Comments on the Quality of English LanguageThere are several grammatical and typographical errors throughout the manuscript. A thorough proofreading is recommended.
Author Response
Firstly, I would like to express my gratitude to the journal for the opportunity to revise and resubmit our manuscript for potential publication. We sincerely appreciate the time and effort invested by the reviewers in evaluating our work and providing constructive feedback. We have carefully considered all comments and incorporated revisions to address them comprehensively. Below, we outline the specific modifications made in response to the reviewers’ recommendations.
Comment 1: The manuscript provides a comprehensive review of anaerobic bioremediation of acid mine drainage (AMD) using sulphate-reducing bacteria (SRB). The topic is relevant to sustainability and environmental management. The authors have presented an extensive overview of the current status, challenges, and future directions of SRB-mediated bioremediation, including a critical analysis of various bioreactor designs and bioremediation strategies. However, there are several aspects that require attention to enhance the clarity, scientific rigor, and overall quality of the manuscript. Below are specific comments and suggestions for improvement. The abstract adequately summarizes the purpose, key findings, and future directions. However, it would benefit from including specific quantitative results or examples to strengthen its impact.
Response: Thank you, I agree with this comment and accurate numbers and specific data examples have now been included in the abstract.
Comment 2: The introduction effectively sets the stage for the study. However, the transition from general environmental pollution to the specific issue of AMD could be more seamless. Consider restructuring the introduction to lead more naturally into the focus on SRB and AMD.
Response: Comment noted thank you, the introduction has been structured are per the requirements.
Comment 3: The review of bioreactor designs is detailed, but the manuscript could be strengthened by providing a comparative analysis of their efficiencies under different conditions.
Response: The efficiency of the different bioreactors under different conditions has been included on Table 4 [See page 9].
Comment 4 and 5: The methodology described for evaluating bioremediation techniques is not fully clear. It would be helpful if the authors could provide a clearer framework or criteria for assessing the success of the bioremediation methods discussed. The tables provided (e.g., Table 1 and Table 4) contain valuable information. However, Table 1 could benefit from reorganization to improve readability. Consider grouping similar variables together or using colour coding to highlight trends.
Response: Table 1 has been regrouped by starting with data with the lowest sulphate concentrations to the highest.
Comment 6: Figures 1 and 2 are informative but could be enhanced with higher resolution and clearer labels.
Response: The resolution for both the figures has been increased.
Comment 7: The discussion provides a balanced view of the advantages and limitations of SRB-based bioremediation. However, it lacks depth in discussing the potential environmental risks associated with the use of SRB, particularly regarding the production of hydrogen sulphide.
Response: Table for advantages and disadvantages has been refined; it now includes the environmental conditions associated with each bioreactor. [See page 9 to 10].
Comment 8: The manuscript mentions genetic engineering of SRB as a future direction but does not explore this idea sufficiently. Including potential genetic modifications or examples from recent studies could enrich this section.
Response: Discussions on potential genetic modification solutions to treat AMD have now been included in the manuscript, [See page 18 and 19].
Comment 9: The conclusion effectively summarizes the findings but could be more impactful by directly linking the key insights to practical applications in environmental management. Suggestion: "Future research must concentration on enhancing bioreactor designs..." should be corrected to "Future research must focus on enhancing bioreactor designs..."
Response: The conclusions have been refined, and the suggested approach of writing has been used effectively.
Comment 10: Some references are not consistently formatted. Ensure compliance with the journal's reference style.
Response: The referencing style was kept constant throughout the referencing list.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsBelow are my observations regarding the modifications made to your manuscript:
The grammatical and structural improvements are evident, and the manuscript is now more readable. The reduction of repetition and simplification of certain terms contribute to a clearer presentation of your findings.
The inclusion of a well-defined literature selection methodology, as well as the criteria for inclusion and exclusion, strengthens the scientific rigor of the review. Additionally, the comparative analysis of SRB-based bioremediation against conventional treatment strategies enhances the manuscript’s depth.
The adjustments made to figure captions and the redrawing of complex illustrations improve the clarity of the visual content. The consistency in table formatting also enhances readability and presentation.
Prioritizing recent literature strengthens the manuscript’s relevance. Ensuring that the latest key studies are incorporated adds value to the discussion.
The extended discussion on technological innovations and economic feasibility significantly improves the manuscript. The additional details provide a more comprehensive perspective on SRB-based bioremediation.
Overall, the revisions have substantially improved the manuscript, and I appreciate the effort taken to refine the content. I look forward to the final version of the paper.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper has been improved and the authours have address all my comments so i recomend to accept this manuscript.
