Effects of Short Retention Times and Ultrasound Pretreatment on Ammonium Concentration and Organic Matter Transformation in Anaerobic Digesters Treating Sewage Sludge
, Gloria Gómez 1,2 and Gladys Vidal 1,2,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article is correct, but it is prepared too generally and needs to be corrected ie:
- the introduction needs to be refined, the information contained is common knowledge and I think it should be expanded a bit,
- the novelty of the work is not emphasized, the ultrasonic disintegration methods used are known and have been used for a very long time, please indicate what is new in the presented research,
-if possible a photo of the test stand or a diagram would be useful,
- the form of presentation of results is illegible, maybe other diagrams? it is difficult to interpret,
-discussion needs to be deepened,
- conclusions I propose to rewrite, because in the current form it is difficult to read,
- statistical analysis???? In the methodology it is described but in the article it is missing.
After the correction, I think the article thematically fits the profile of the journal.
Author Response
Dear Editor,
The response for the comments of the Reviewer 1 is attached below.
Best regards,
Gladys Vidal
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors evaluated the effect of ultrasound and Ammonium on the AD process. This reviewer believes this manuscript might be considered to be published after addressing the following issues:
Abstract
- Please add a sentence regarding the background in the beginning.
Introduction
- Authors should give a brief but comprehensive review of the effect of ultrasound and Ammonium on the AD process. More importantly, authors should clearly explain the novelty of this work compared with the previous studies.
- Very similar to ultrasound, hydrodynamic cavitation is also a promising activation means for pretreatment of sewage sludge, which is worth to mentioning. There are some papers for reference:
1. 10.1016/j.jece.2020.104743
2. 10.1016/j.ultsonch.2023.106544
Results
- A comparison of degradation performance and economical efficiency between the present work and previous similar works is recommended.
- Instead of only describing the effect of the two pretreatments, please also mention their intensification mechanism according to the previous works.
- Please also discuss the application potential of the two pretreatments
Conclusion
- objectively pointing out some weaknesses of this work is helpful.
- please also provide some inspirations and guidances to the readers.
Author Response
Dear Editor,
The responses of the comment by Reviewer 2 are attached below.
With my best reagards,
Gladys Vidal
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe author investigated the effects of ultrasound and residence time on anaerobic digestion for sludge treatment. There are many previous works on this topic. The author needs to highlight its specific novelty and importance in the Introduction. The description in the results and discussion section appeared overly simplistic, lacking essential microbial community data. It was recommended to enhance the comprehensiveness of the analysis by incorporating information regarding the influence mechanisms of ultrasound and residence time on sludge anaerobic digestion.
Some specific comments/concerns can be found below.
1. Introduction: More discussion is needed on the impacts of sludge residence time on anaerobic digestion. The novelties should be highlighted.
2. The ORP in Figure ed to be unreasonable; typically, the ORP range for methanogenesis should be between -300 and -400 mV. Why the ORP in phase II was lower than that in phase I, however, the higher methane yield was obtained in phase I.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
Dear Editor,
Attached you can find the response for Reviewer 3.
With my best regards,
Gladys
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have greatly improved the articles with the changes made.
Accepts in its current form.
Reviewer 2 Report
Comments and Suggestions for AuthorsNecessary modifications have been made.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe description in the results and discussion section appeared overly simplistic, lacking essential microbial community data.
