Dark Fermentation of Sizing Process Waste: A Sustainable Solution for Hydrogen Production and Industrial Waste Management

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I reviewed the manuscript. However, I believe it would greatly benefit from further elaboration in certain aspects to bolster the clarity and impact of your paper. Notably, the methodology section requires more detailed descriptions to aid readers in fully understanding your approach. Additionally, integrating a broader range of supporting references would provide a stronger foundation for your arguments and enrich the contextual background of your study. Moreover, I found that some sections of the results were presented ambiguously. By clarifying these sections, you will enhance the overall effectiveness and persuasiveness of your research.

Lines 59-61: To further enhance the discussion on biohydrogen production and the valorization of fermentation by-products, we recommend including the reference “https://doi.org/10.1016/j.cej.2025.159536”. Although not directly focused on hydrogenases, this recent work offers valuable insights into the circular utilization of organic by-products and innovative bio-based processes for energy and material recovery. Citing it could enrich the background on sustainable applications of fermentation-derived compounds, strengthening the case for eco-friendly hydrogen production.

Lines 111-120: Could you delve into the environmental implications of the sizing process in the textile industry, especially focusing on the generation of wastewater? How significant is the impact of this wastewater on local water bodies, and what measures are typically employed to mitigate such impacts? Furthermore, could you explore whether there are more environmentally friendly alternatives to starch as a sizing agent that could reduce the environmental burden of the process?

Lines 131-134: I recommend citing the article "https://doi.org/10.1016/j.clet.2025.100905" in your context. This citation would provide additional support for the argument that anaerobic fermentation can play a role in enhancing sustainability within the textile industry. It will offer a broader perspective on the integration of environmental technologies into industrial applications, which can enrich the discussion about the potential benefits of adopting circular economy principles. Adding this source will also strengthen the theoretical foundation of your study by linking it to established research on converting waste to valuable resources through innovative environmental technologies.

Lines 187-205: To strengthen the methodological section and provide readers with a broader perspective on analytical protocols for VFA quantification and gas composition analysis, it is recommended to cite the article "https://doi.org/10.1016/j.chemosphere.2022.134500". Although the cited study may not focus exclusively on the same substrate or system, it applies comparable analytical techniques under similar experimental conditions. Referencing it would not only enrich the methodological framework but also support the reliability and relevance of the chosen instruments and procedures.

Lines 219-231: Can you clarify the apparent discrepancy between the significant reduction in total volatile solids (TVS) and the relatively stable levels of dissolved organic carbon (DOC) in the non-starch variants during the dark fermentation (DF) process? How do you account for the hypothesis that DOC remained constant due to conversion into more stable forms, despite effective TVS degradation? Could the limited variation in DOC be linked to analytical sensitivity, incomplete hydrolysis, or the formation of recalcitrant organic compounds not easily detected in standard DOC assays?

Lines 252-274: Given that butyric acid was consistently the dominant volatile fatty acid (VFA) across all variants, could you clarify why modified starch—despite promoting higher overall VFA production—did not significantly alter the relative composition of butyric acid compared to natural starch? Furthermore, considering the stark differences in caproic and isovaleric acid levels between modified and natural starch variants, how do you interpret the underlying biochemical or microbial mechanisms driving these selective shifts in VFA profiles? Lastly, could the trace detection of isobutyric acid only in the modified, unheated starch variant indicate a specific microbial pathway being favored, and if so, why might heating suppress this effect?

Lines 287-317: Could you clarify how the observed increase in caproic acid production in modified starch variants mechanistically interferes with hydrogen yields? How do the electron allocation and metabolic fluxes shift in favor of chain elongation at the expense of H₂ production? Considering the heating-induced increase in H₂ generation in modified starch variants, to what extent do you attribute this effect to thermal activation of enzymes versus a shift in microbial community dynamics? Lastly, has the impact of starch modification on substrate bioavailability been quantitatively characterized, for example, through structural analyses or enzymatic hydrolysis rates, to support the link between starch structure and fermentation efficiency?

Author Response

Dear Sir or Madam, 

thank you very much for the valuable remarks concerning our manuscript. Below are the responses to your review.

• Lines 59-61: To further enhance the discussion on biohydrogen production and the valorization of fermentation by-products, we recommend including the reference “https://doi.org/10.1016/j.cej.2025.159536”. Although not directly focused on hydrogenases, this recent work offers valuable insights into the circular utilization of organic by-products and innovative bio-based processes for energy and material recovery. Citing it could enrich the background on sustainable applications of fermentation-derived compounds, strengthening the case for eco-friendly hydrogen production.

The reference to the indicated article has been added to the manuscript.

• Lines 111-120: Could you delve into the environmental implications of the sizing process in the textile industry, especially focusing on the generation of wastewater? How significant is the impact of this wastewater on local water bodies, and what measures are typically employed to mitigate such impacts? Furthermore, could you explore whether there are more environmentally friendly alternatives to starch as a sizing agent that could reduce the environmental burden of the process?

A detailed explanation addressing the environmental implications of the sizing process, the impact of wastewater on local water bodies, typical mitigation measures, and environmentally friendly alternatives to starch has been added to the manuscript.

• Lines 131-134: I recommend citing the article "https://doi.org/10.1016/j.clet.2025.100905" in your context. This citation would provide additional support for the argument that anaerobic fermentation can play a role in enhancing sustainability within the textile industry. It will offer a broader perspective on the integration of environmental technologies into industrial applications, which can enrich the discussion about the potential benefits of adopting circular economy principles. Adding this source will also strengthen the theoretical foundation of your study by linking it to established research on converting waste to valuable resources through innovative environmental technologies.

The reference to the indicated article has been added to the manuscript.

• Lines 187-205: To strengthen the methodological section and provide readers with a broader perspective on analytical protocols for VFA quantification and gas composition analysis, it is recommended to cite the article "https://doi.org/10.1016/j.chemosphere.2022.134500". Although the cited study may not focus exclusively on the same substrate or system, it applies comparable analytical techniques under similar experimental conditions. Referencing it would not only enrich the methodological framework but also support the reliability and relevance of the chosen instruments and procedures.

The reference to the indicated article has been added to the manuscript.

• Lines 219-231: Can you clarify the apparent discrepancy between the significant reduction in total volatile solids (TVS) and the relatively stable levels of dissolved organic carbon (DOC) in the non-starch variants during the dark fermentation (DF) process? How do you account for the hypothesis that DOC remained constant due to conversion into more stable forms, despite effective TVS degradation? Could the limited variation in DOC be linked to analytical sensitivity, incomplete hydrolysis, or the formation of recalcitrant organic compounds not easily detected in standard DOC assays?

The observed discrepancy between the significant reduction in TVS and the relatively stable DOC levels in the non-starch variants during DF has been addressed in the revised manuscript. We hypothesize that the limited variation in DOC may be attributed to the conversion of organic matter into more stable, non-volatile compounds, the formation of recalcitrant organics not fully captured by standard DOC assays, or the limited sensitivity of the method used. Additionally, incomplete hydrolysis of certain components may have contributed to the apparent DOC stability despite overall TVS degradation.

• Lines 252-274:

Given that butyric acid was consistently the dominant volatile fatty acid (VFA) across all variants, could you clarify why modified starch—despite promoting higher overall VFA production—did not significantly alter the relative composition of butyric acid compared to natural starch?

Furthermore, considering the stark differences in caproic and isovaleric acid levels between modified and natural starch variants, how do you interpret the underlying biochemical or microbial mechanisms driving these selective shifts in VFA profiles?

Lastly, could the trace detection of isobutyric acid only in the modified, unheated starch variant indicate a specific microbial pathway being favored, and if so, why might heating suppress this effect?

As noted in the revised manuscript, although modified starch enhanced total VFA production, the relative dominance of butyric acid likely reflects the metabolic preference of the microbial community under the specific fermentation conditions used. The observed differences in caproic and isovaleric acid levels may be attributed to shifts in microbial populations or enzymatic activities influenced by the structural and chemical properties of the starch variants. The trace detection of isobutyric acid exclusively in the modified, unheated starch variant could suggest the activation of specific fermentation pathways – possibly involving branched-chain amino acid metabolism – which may be inhibited or suppressed by thermal treatment altering substrate availability or microbial viability.

• Lines 287-317:

Could you clarify how the observed increase in caproic acid production in modified starch variants mechanistically interferes with hydrogen yields? How do the electron allocation and metabolic fluxes shift in favor of chain elongation at the expense of H₂ production?

Considering the heating-induced increase in H₂ generation in modified starch variants, to what extent do you attribute this effect to thermal activation of enzymes versus a shift in microbial community dynamics?

As addressed in the revised manuscript, the increase in caproic acid production in modified starch variants likely reflects a shift in electron allocation toward chain elongation pathways, which compete with hydrogen-producing pathways for reducing equivalents (e.g., NADH, reduced ferredoxin). This metabolic rerouting reduces the availability of electrons for hydrogen evolution. Regarding the heating-induced increase in H₂ production, we suggest that it may be due to a combination of thermal activation of hydrolytic enzymes improving substrate accessibility and a shift in microbial community structure favoring hydrogenogenic species.

Lastly, has the impact of starch modification on substrate bioavailability been quantitatively characterized, for example, through structural analyses or enzymatic hydrolysis rates, to support the link between starch structure and fermentation efficiency?

In this study, the starch used for fermentation was obtained as part of real industrial wastewater from the sizing process, rather than as an isolated or purified substrate. Therefore, detailed structural analyses or enzymatic hydrolysis assays of the starch component were not conducted. Our focus was on evaluating the fermentation performance of the full wastewater matrix as received, to better reflect real process conditions. We acknowledge that future studies involving isolated starch fractions could help elucidate the precise relationship between starch structure, bioavailability, and fermentation efficiency.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present results from a study aimed at producing biohydrogen (H₂) from industrial textile wastewater generated during the warp sizing process. The study investigates the effect of different starch types used in sizing and the impact of thermal pre-treatment on hydrogen production during dark fermentation. While the topic is thematically relevant and potentially valuable, the manuscript lacks the depth and breadth expected of a full article. The content may be more appropriately suited for publication as a short communication. I therefore defer to the Editor’s judgment regarding its suitability for publication in its current form.

Specific comments

Abstract: The abstract lacks specific numerical data to support its claims. Instead of using vague terms like 'less' (line 13), 'high', or 'higher', please provide exact numbers or percentages to give the reader a clearer understanding of the results.

Introduction:

Line 124: What does “often not properly managed” mean?

Line 185: Define the acronym VFA

Results and discussion: Please remove the numerical values displayed on top of each bar in Figures 1, 2, and 3, as they are redundant if the data are already represented visually.

Figure 1, 2, 3, 4, and 6:

• What does the (-) beside the pH in Figure 1 mean?
• Please comment on the reproducibility of the results by specifying how many times each experiment was performed. Additionally, include statistical analysis data (e.g., mean ± standard deviation, p-values) to support the significance of the findings.

Author Response

Dear Sir or Madam, 

thank you very much for the valuable remarks concerning our manuscript. Below are the responses to your review.

• Specific comments

Abstract: The abstract lacks specific numerical data to support its claims. Instead of using vague terms like 'less' (line 13), 'high', or 'higher', please provide exact numbers or percentages to give the reader a clearer understanding of the results.

In response, we have revised the Abstract to replace vague qualitative terms such as "less," "high," and "higher" with specific numerical data and percentages. This provides a clearer and more precise summary of the results and strengthens the overall impact of the Abstract.

Introduction:

• Line 124: What does “often not properly managed” mean?

By "often not properly managed," we mean that wastewater from the textile sizing process is frequently neither pretreated nor adequately treated before discharge, which can lead to environmental pollution. These wastewaters are sometimes released directly into the environment or handled in ways that do not sufficiently reduce their harmful effects. We have clarified this point in the revised manuscript to better explain the risks associated with improper management.

• Line 185: Define the acronym VFA

Thank you for your observation. The acronym VFA has now been defined at its first occurrence as volatile fatty acids to ensure clarity for the reader.

• Results and discussion: Please remove the numerical values displayed on top of each bar in Figures 1, 2, and 3, as they are redundant if the data are already represented visually.

We have removed the numerical values displayed above each bar in Figures, as they were redundant given the visual representation of the data. The figures have been updated accordingly to improve clarity and readability.

Figure 1, 2, 3, 4, and 6:

• What does the (-) beside the pH in Figure 1 mean?

The “(–)” beside the pH in Figure 1 was unintentional and may cause confusion. We have corrected the figure to either remove the symbol  as pH is a logarithmic measure and does not require a unit. The revised figure now clearly presents the pH values without unnecessary notation.

• Please comment on the reproducibility of the results by specifying how many times each experiment was performed. Additionally, include statistical analysis data (e.g., mean ± standard deviation, p-values) to support the significance of the findings.

In response, we have clarified the reproducibility and statistical analysis of our experiments in the revised manuscript. Specifically, all analyses were performed using three independent repetitions (samples) for each experimental condition. The resulting data were statistically processed to calculate mean values and standard deviations, which allowed us to assess both the variability and reliability of the results. This information has been added to the manuscript to ensure transparency and clarity regarding the statistical treatment of our data.

Reviewer 3 Report

Comments and Suggestions for Authors

May 8, 2025

Comments for 3602343

Journal : Water

Authors : Marlena Domińska, Martyna Gloc, Magdalena Olak – Kucharczyk, Katarzyna Paździor

Title : Dark Fermentation of Sizing Process Waste: A Sustainable Solution for Hydrogen Production and Industrial Waste Management

The subject of the study is generally appropriate for Water, according to the journal aim and scope. The topic is interesting and deals with topical issues. However, I have some observations related manuscript and some suggestions to the authors.

Special comments:

The title seems too broad given the scope of the research carried out.

Introduction

• Line 52: The nomenclature of hydrogen involving colours is not entirely systematised. The term ‘golden hydrogen’ appears in relation to hydrogen produced from direct solar water splitting, while ‘gold hydrogen’ is used for naturally occurring hydrogen, although the name ‘white hydrogen’ can also be found.

Please see, for example, this paper:

Foster Lubbe, Jan Rongé, Tom Bosserez, Johan A. Martens, Golden hydrogen, Current Opinion in Green and Sustainable Chemistry, Volume 39, 2023, 100732, ISSN 2452-2236, https://doi.org/10.1016/j.cogsc.2022.100732.

It is worthwhile at this point to refer to specific nomenclature or mention these ambiguities.

• Line 69: In the context of the limitations of DF, it is worth mentioning carbon dioxide, which is also produced in this process and whose sequestration is also a challenge.

2.1. Inoculum and substrate

• Line 164: Table 1 - Please, add an explanation of what the +/- value means and in how many repetitions (samples?) the determinations were made.

2.2. Experimental Setup: This chapter needs to be improved. In my opinion, the following information is missing:

• How many samples/repeats were analysed? How much data was statistically processed? This is important information, also with regard to the accuracy of the results presented in the chapter (lines 260 and 264).
• What were the mixing parameters?
• What were the reasons for running the experiment for 48h?
• Why was dissolved oxygen concentration control not included?

 

• The effect of NH₄⁺ ion concentration on hydrogen production efficiency may be important, why was the ammonium nitrogen concentration not determined?
• Line 235: Figure 3. DOC dynamics during the dark fermentation: initial and final values – this title seems to promise too much.

 

• Lines 187-205: I am not in a position to judge, as I am not an expert in chromatography.

Conclusions

• Lines 334-335: „Based on TN analysis, it can be concluded that the differences between variants are due to different nitrogen processing mechanisms by microorganisms.” – Again: an analysis of nitrogen forms seems necessary. Perhaps this should be one of the conclusions - as a direction for further research.
• Microbiological analyses should also be indicated as a direction for further research.

Comments for author File: Comments.pdf

Author Response

Dear Sir or Madam, 

thank you very much for the valuable remarks concerning our manuscript. Below are the responses to your review.

1. Introduction

• Line 52: The nomenclature of hydrogen involving colours is not entirely systematised. The term ‘golden hydrogen’ appears in relation to hydrogen produced from direct solar water splitting, while ‘gold hydrogen’ is used for naturally occurring hydrogen, although the name ‘white hydrogen’ can also be found.

Please see, for example, this paper:

Foster Lubbe, Jan Rongé, Tom Bosserez, Johan A. Martens, Golden hydrogen, Current Opinion in Green and Sustainable Chemistry, Volume 39, 2023, 100732, ISSN 2452-2236, https://doi.org/10.1016/j.cogsc.2022.100732.

It is worthwhile at this point to refer to specific nomenclature or mention these ambiguities.

Thank you for pointing this out. The reference to "gold hydrogen" was indeed taken from another source without sufficient verification, which was an oversight on my part. Upon closer examination, we recognize that the nomenclature of hydrogen colors is not fully standardised, and terms such as "golden hydrogen," "gold hydrogen," and "white hydrogen" are used inconsistently in the literature. We have removed the statement to avoid confusion as suggested. Thank you for bringing this to our attention.

• Line 69: In the context of the limitations of DF, it is worth mentioning carbon dioxide, which is also produced in this process and whose sequestration is also a challenge.

We have added a mention of carbon dioxide (CO₂) as a byproduct of the dark fermentation (DF) process in the revised manuscript. While the focus of the study was on volatile fatty acids and hydrogen production, we acknowledge that CO₂ sequestration also presents an environmental challenge in the context of DF. This addition aims to provide a more comprehensive overview of the limitations of the process. We have cited relevant studies addressing CO₂ capture and utilization in the updated manuscript.

2.1. Inoculum and substrate

• Line 164: Table 1 - Please, add an explanation of what the +/- value means and in how many repetitions (samples?) the determinations were made.

We have added an explanation to Table 1 regarding the meaning of the ± value. The values represent the standard deviation, and the determinations were made from 3 repetitions (samples). This information has been included in the revised manuscript for clarity.

2.2. Experimental Setup: This chapter needs to be improved. In my opinion, the following information is missing:

• How many samples/repeats were analysed? How much data was statistically processed? This is important information, also with regard to the accuracy of the results presented in the chapter (lines 260 and 264).

The analyses were performed using 3 repetitions (samples) for each experimental condition. The data was statistically processed to calculate the mean values and the standard deviation, which were used to assess the variability and accuracy of the results presented. We have included this information in the revised manuscript to clarify the statistical treatment and the reliability of the data.

• What were the mixing parameters? The mixing was performed at a constant speed of 140 rpm throughout the experiments. This information has been added to the revised manuscript for clarity.
• What were the reasons for running the experiment for 48h?

The experiments were conducted over a period of 48 hours to ensure that the process had fully ceased and no further gas generation occurred, thereby improving the accuracy and completeness of the measurements. Although hydrogen production was primarily observed during the first 24 hours, the extended duration was necessary to capture any potential delayed gas evolution and to confirm the stability of the system.

• Why was dissolved oxygen concentration control not included?

Dissolved oxygen (DO) concentration was not monitored during the experiments. This decision was made due to the nature of the substrate, which was complex and heterogeneous, making accurate readings of COD (Chemical Oxygen Demand) or DO difficult and potentially unreliable in this context. As a result, the focus was on gas production parameters, which are more reliable and reflect the fermentation activity in such systems.

• The effect of NH4+ ion concentration on hydrogen production efficiency may be important, why was the ammonium nitrogen concentration not determined?

The concentration of ammonium nitrogen (NH₄⁺) was not determined at this stage of the study, as the primary objective was to assess the overall potential for hydrogen production using inoculum obtained from a municipal wastewater treatment plant. It was assumed that the ammonium levels inherently present in the activated sludge were adequate to support fermentative hydrogen production under the applied conditions.

Nevertheless, it is acknowledged that ammonium nitrogen may influence hydrogen production efficiency, particularly through its effects on microbial metabolism and nutrient availability. For this reason, the determination of NH₄⁺ concentration is planned for future stages of the research to enable a more comprehensive evaluation of its role in the process.

• Line 235: Figure 3. DOC dynamics during the dark fermentation: initial and final values – this title seems to promise too much.

In response to your suggestion, we have revised the title of Figure 3 to: "DOC Changes During Dark Fermentation: Initial and Final Values." This modification was made to better reflect the content of the figure and the nature of the data presented, ensuring that the title is more accurate and appropriately descriptive.

• Lines 187-205: I am not in a position to judge, as I am not an expert in chromatography.

3. Conclusions

• Lines 334-335: „Based on TN analysis, it can be concluded that the differences between variants are due to different nitrogen processing mechanisms by microorganisms.” – Again: an analysis of nitrogen forms seems necessary. Perhaps this should be one of the conclusions - as a direction for further research.

Microbiological analyses should also be indicated as a direction for further research.

We agree that a more detailed analysis of nitrogen species is essential to confirm the differences observed between variants. We have therefore highlighted this as an important direction for future research. Additionally, we have acknowledged the need for microbiological analyses to better understand the underlying biological mechanisms. These points have been incorporated into the manuscript to guide further investigations.

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript titled "Dark Fermentation of Sizing Process Waste: A Sustainable Solution for Hydrogen Production and Industrial Waste Management”,

 

The manuscript investigates the potential of producing hydrogen (H₂) from sizing waste, focusing on 11 starch-based substrates through dark fermentation. The authors aimed to compare hydrogen yields from natural and modified starches and explore how heat treatment affects the process. They found that natural starches produced more H₂, especially when unheated, due to the predominance of the butyric-acetic fermentation pathway. In contrast, modified starches promoted fatty acid chain elongation, resulting in lower H₂ and CO₂ levels. The study also examined organic matter conversion, carbon degradation, and nitrogen processing, concluding that sizing waste is a promising substrate for sustainable biohydrogen production and offers directions for industrial application

After revision manuscript can be published.

I suggest author to address the following questions and comments:

1. The introduction is well-developed, but I miss "a few" words about the conditions of conducting DF. Such as temperature, ph, etc. Please add this information around L53-59.
2. Please explain the abbreviation DOC as was done for TS and TVS.
3. Is the pH of the inoculum 7.25 , i.e. the pH determined after heat treatment (70C?)
4. The literature shows that DF is most effective at pH lower than 7 (5-6pH), why didn't the authors correct the initial pH? Please justify the assumption.
5. While the experimental setup is described, I am missing a description of the fermentation. How much substrate was given, how much inoculum? What was the assumption regarding the reactor load? Was 0.5L the working volume of the reactor? Please add this information in the materials&methods section. The results are in the results.
6. Experiments were performed in triplicate, please include SD in the graphs.
7. What does TVSKW mean in Figure 6?

Author Response

Dear Sir or Madam, 

thank you very much for the valuable remarks concerning our manuscript. Below are the responses to your review.

• The introduction is well-developed, but I miss "a few" words about the conditions of conducting DF. Such as temperature, ph, etc. Please add this information around L53-59.

Information regarding the key conditions of DF process – including temperature, pH, and other relevant parameters – has been added in the revised version of the manuscript. These additions aim to provide better context for the experimental setup and facilitate a clearer understanding of the conditions under which hydrogen production was evaluated.

• Please explain the abbreviation DOC as was done for TS and TVS.

The abbreviation DOC (Dissolved Organic Carbon) has now been explained in the manuscript, in the same manner as TS (Total Solids) and TVS (Total Volatile Solids), to ensure clarity and consistency for the reader.

• Is the pH of the inoculum 7.25 , i.e. the pH determined after heat treatment (70C?)

The reported pH value of 7.25 refers to the pH of the inoculum measured after the heat treatment at 70C. This clarification has now been added to the table 1 caption to avoid any ambiguity.

• The literature shows that DF is most effective at pH lower than 7 (5-6pH), why didn't the authors correct the initial pH? Please justify the assumption.

While it is true that the optimal pH range for dark fermentation is often reported to be between 5.0 and 6.0, in our previous studies conducted on different types of organic waste, we observed that adjusting the initial pH to 6 had a markedly negative effect on hydrogen production efficiency. Based on these findings, we decided not to modify the initial pH in the present study.

This approach was adopted to preserve the natural buffering capacity and microbial balance of the inoculum, particularly considering its origin from a wastewater treatment plant, where pH stability tends to be favorable for mixed microbial communities. The initial pH of 7.25 was therefore maintained without further adjustment.

• While the experimental setup is described, I am missing a description of the fermentation. How much substrate was given, how much inoculum? What was the assumption regarding the reactor load? Was 0.5L the working volume of the reactor? Please add this information in the materials&methods section. The results are in the results.

Additional details regarding the fermentation process – including the amount of substrate and inoculum used, the working volume of the reactor (0.5 L), and the assumptions related to reactor loading – have been added to the manuscript section to clarify the experimental setup. We believe this information will enhance the transparency and reproducibility of the study.

• Experiments were performed in triplicate, please include SD in the graphs.

Standard deviations (SD) have now been included in the graphs to reflect the variability between replicates. This addition enhances the clarity and reliability of the presented results.

• What does TVSKW mean in Figure 6?

The label “TVSKW” in Figure 6 was a typographical error. It has been corrected in the revised version of the figure to accurately reflect the intended parameter. We apologize for the oversight.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I am delighted to observe the significant improvements you have made to the manuscript. The extensive revision work has greatly enhanced the structure of the paper, as well as the clarity of the methodologies and the presentation of results. Your efforts in refining and strengthening each section are commendable. The manuscript now provides a clear, well-articulated exploration of the topics at hand, making it a valuable contribution to the field.

Reviewer 2 Report

Comments and Suggestions for Authors

Domińska et al addressed the comments adequately, therefore, I suggest accepting the revised manuscript.