Recent Advances and Perspectives of Nanotechnology in Anaerobic Digestion: A New Paradigm towards Sludge Biodegradability
Round 1
Reviewer 1 Report
Comments for Manuscript sustainability-1578536
Journal: Sustainability (ISSN 2071-1050)
Title: Recent advances and perspectives of nanotechnology in anaerobic digestion: A new paradigm towards sludge biodegradability
In this review, the authors focus on the impact of nanomaterials such as metallic nanoparticles, metal oxide nanoparticles, carbon-based nanomaterials, and nanocomposite materials in AD enhancement. The authors also assess the potential of utilizing these nanomaterials in enhancing AD under various conditions.
The following comments on the content should be addressed before being published:
- Line 11: There is a spelling mistake and in need of statement modification - “Evironmentally sustainable bioenergy producing strategy from waste activated sludge (WAS) is anaerobic digestion (AD) but its efficiency was hindered by low biodegradability.”
- Lines 14: Spelling error and Hanging sentence. “Application of nanomaterials in sludge wer through reviewed.” I think the abstract clearly needs proofreading.
- Line 15: This paper does not seem to discuss the techniques but rather only the effects. Please revise.
- Line 28: Where is the correlation between energy and wealth? The statement needs additional information to show the interlinking of the 2 terms.
- Lines 32-33: Referring to the sentence “Thus, bioenergy is considered to be a better option for bioenergy production in societal concern”, the repeated word “bioenergy” seems out of place. Rephrase the sentence.
- Lines 40-51: Provide information about sludge biodegradability, the current problems, and the “new paradigm” as suggested in the title. What about the cost of introducing nanomaterials in AD? This aspect should be elaborated accordingly.
- Line 53: is it referred to as a different source. Add in the term adapted or modified from..... (cite the source).
- Line 74: why use the word nutritional source? Is it not a binding source or an initiator source?
- In Figure 2, I wonder where did the authors get the information. Please add suitable reference(s) and also the percentage sign “%” to the figures. Also, Figure 2 contains many glaring spelling errors
- Metallic nanoparticles section: What are the differences in terms of the performance of these materials in bulk and their respective nanosize materials? Are they remain co-factors regardless of the size?
- Line 84: “…12.1 % of total and volatile solids removal was obtained…” Did the author mean total suspended solids? And also in Line 88: TSS shall be written in full term.
- Line 220: Italicize the bacteria genus, Line 282: Methanosarcina and Methanobacterium Anaerolineaceae and Longilinea, Line 292- Italicize Geobactor… and many others.
- Line 434: Remove “achieved a”
- Line 441: USD or $ for the currency? Please be consistent
- Figure 3: increase what diversity? Indicate in the figure
- Line 269: Where is Figure 5??
- Line 362: advantage 2 seems very long and confusing. Strengthen the connections among microbes and NPs (might be an effective technique for improving NP re-activity and performance).
- Line 430: Which analysis method was used by the author to calculate the energy output and cost-benefit analysis?
- Something important seems to be missing from the article. Can the authors make a logical case that, by using NPs in AD, they are feasible and effective enough? Explain this at the end of this section or at the conclusion section.
- It seems that the current demand for AD industrialization might be a poor predictor for future demand. Nanomaterials in this regard would be a candidate to replace many other conventional materials/processes for more efficient sludge biodegradability. This aspect ought to be discussed, with suitable literature references.
Conclusion
- Add challenges and how to overcome in at the beginning of the conclusion part.
Overall
- Suggest to include the chemical nomenclature for all the abbreviation that is used. Example the IUPAC name indicated in this paper for CeO2
- Synchronise use either % or word “percent”, g/l or g/L throughout the manuscript
- Please refine the English quality, citation formatting etc. of this manuscript for better readibility.
Author Response
Dear reviewer, we appreciate the contributions reported to our paper and emphasize that we accept all suggestions and seek to solve them. We hope that the new text is satisfactory.
In general, the paper was rewritten with greater clarity, coherence and conciseness providing a better fluidity of the subject for the reader. We sought to eliminate all the problems mentioned by the reviewers.
We thank you in advance for your attention and look forward the acceptance of the paper.
Regards,
The authors.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors reported on the “Recent advances and perspectives of nanotechnology in anaerobic digestion: A new paradigm towards sludge biodegradability” This study is of interest, arranged in an organized way, and has a certain significance for various implementations. The following are some suggestions for improvement.
- The conclusion should be concise and to the point indicating the application of the work.
- The text would be smoother if some introductory/linking text is added to explain why it is important to draw such great attention to this particular assay.
- Nanomaterials have attracted a lot of attention in the field of study because of their unique physical qualities such as greater surface area and structure, particle size, catalytic activity, and so on. The following references may be added to the manuscript
- Colloids and Surfaces A: Physicochemical and Engineering Aspects 642 (2022)128659
- Arabian Journal of Chemistry 15 (2) (2022) 103588
- Chinese Journal of Chemical Engineering (2022), https://doi.org/10.1016/j.cjche.2021.11.024
- Applied Physics A 127, Article number: 296 (2021).
- Reac Kinet Mech Cat (2017) 120:791–807.
- Materials Chemistry and Physics 241 (2020) 122403.
Author Response
Dear reviewer, we appreciate the contributions reported to our paper and emphasize that we accept all suggestions and seek to solve them. We hope that the new text is satisfactory.
In general, the paper was rewritten with greater clarity, coherence and conciseness providing a better fluidity of the subject for the reader. We sought to eliminate all the problems mentioned by the reviewers.
We thank you in advance for your attention and look forward the acceptance of the paper.
Regards,
The authors.
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper, entitled Recent advances and perspectives of nanotechnology in anaerobic digestion: A new paradigm towards sludge biodegradability, is a scholarly work and can increase knowledge on this domain. The authors provide an interesting and original paper, the content is relevant to Sustainability. The abstract and keywords are meaningful.
I have some specific and general comments:
- Please introduce the subject of your work in the section Introduction,the objectives and goals should be better introduced, the section Introduction is quite short and should be improved.
- Please provide a link between the sections 1. Introduction and 2. Various nanomaterials in AD enhancement.
- In section 2. Various nanomaterials in AD enhancement, the authors mentioned lines 55-57 page 2 that "Enhancement of AD using nanomaterials... received a great consideration..." but there's only two references related to this assertion ([11] and [12]). Please provide more references, there's many references dealing with this aspect. The addition of nanomaterials is in the spotlight of current research work. By this way, the manuscript should be more related to existing literature. The Figure 2 was built from data and information from literature but there's no reference related.
- I have the same comment for all the following section, from my point of view, authors need to provide more references. This paper is announced as a compilation on the topic with a title starting with "Recent advances and perspectives...", so readers will wait for these information and wish find references dedicated to this topic.
- About the compilation of data carried out in the several Tables, the authors made a great work of compilation. From my point of view, these Tables should completed with some information such as the scale of work for all the references listed here. Is it labscale, pilot-scale, other? The amount of materials involved in these experiments was given, but there's no indication about the total volume of work? What are the costs of such approaches?
- The section 4. Future perspectives on AD enhancement is quite short and should be improved. Please discuss more and provide detailed discussion.
As it, this paper is not fully acceptable for publication and requires some amendments and additional information according to the comments listed previously. I recommend the following decision: RECONSIDER AFTER MAJOR REVISION.
Author Response
Dear reviewer, we appreciate the contributions reported to our paper and emphasize that we accept all suggestions and seek to solve them. We hope that the new text is satisfactory.
In general, the paper was rewritten with greater clarity, coherence and conciseness providing a better fluidity of the subject for the reader. We sought to eliminate all the problems mentioned by the reviewers.
We thank you in advance for your attention and look forward the acceptance of the paper.
Regards,
The authors.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have made significant changes to the manuscript. Only minor corrections are needed. Example please refine "Gole" (Au) in Line 91 and new paragraph spacing in Line 67.
Author Response
Dear reviewer, we appreciate the contributions reported to our paper and emphasize that we accept all suggestions and seek to solve them. We hope that the new text is satisfactory.
In general, the paper was rewritten with greater clarity, coherence and conciseness providing a better fluidity of the subject for the reader. We sought to eliminate all the problems mentioned by the reviewers.
We thank you in advance for your attention and look forward the acceptance of the paper.
Regards,
The authors.
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors provide detailed and justified answers to all comments and requests of amendments made in the previous review. I agree with all the answers.
There's few minor modifications or amendments to carry out:
- please check Figure 1, especially the words Acidogenesis and Methanogenesis, it seems that there's some mistakes of spelling/writing them.
- In Table 3, please mention working volume below Lab scale for the several lines of the Table
After these last modifications, the manuscript should be acceptable for publication and could be published. I recommend the following decision: ACCEPT AFTER MINOR REVISION.
Author Response
Dear reviewer, we appreciate the contributions reported to our paper and emphasize that we accept all suggestions and seek to solve them. We hope that the new text is satisfactory.
In general, the paper was rewritten with greater clarity, coherence and conciseness providing a better fluidity of the subject for the reader. We sought to eliminate all the problems mentioned by the reviewers.
We thank you in advance for your attention and look forward the acceptance of the paper.
Regards,
The authors.
Author Response File: Author Response.pdf
