Kinetics of Biotic and Abiotic CO Production during the Initial Phase of Biowaste Composting

Round 1

Reviewer 1 Report

The text, and especially the results and discussion, are too long. There is a lot of repetition in the text. Try not to describe what can be seen from the picture or table. Strive to visualize research results. Perhaps give specific examples, if possible, that CO emissions have caused certain health problems for workers in the composting process. Is there an assessment of the risk of CO poisoning in composting and its quantitative comparison with the risks of other substances (gases, particles or microorganisms) that affect the health of workers in an aerobic biological waste treatment plant?

Author Response

Our reply is in the attached file.

Author Response File: Author Response.docx

Reviewer 2 Report

The authors reported a manuscript in which they modeled the kinetics of CO production during biowaste composting for the prediction of the evolution and estimation of the total amount of gas generated. The study carried out by the authors could be of interest to the readers of Energies journal.

Specific comments:

-It must add the following keywords: kinetic modelling, GHGs mitigation.

-It must add the error bars in control of the experiments.

-In line 334 you must specify which type of easily biodegradable organic substances led to high respiratory activity.

-In lines 425-427 it must specify which type of chemical bond is broken or towards which type of structures the organic waste is modified. You can attach some evidence to support your claim.

-In lines 435-438 it can be explained that the change in curvature observed is due to a change in the control regime of the oxidation reaction. In the first moments it governs the biotic process (with a pseudo-first order kinetics) until once a temperature is reached in which a thermochemical regime governs (with a zero order kinetics).

-In lines 452-460 it should complete this paragraph with some more detail, the socio-economic impact that this predictive model would have on GHG mitigation.

-The conclusion of line 476 has not been proved in this study. It should be deleted.

Author Response

Our reply is in the attached file.

Author Response File: Author Response.docx

Reviewer 3 Report

Interesting project relating to a kinetic study of CO production through biowaste aerobic biostabilization. However some issues arise from the analysis of the paper which are presented in more detail below.

Since the paper intends to be a kinetic study of a specific process, it should be expected a deeper emphasis in the core of the paper on the presentation of the particular kinetic data obtained and related interpretation in a concise manner. However a significant part of this crucial data in referred mainly to the Supplementary Material (available in an xls file), which makes the understanding of the rather long discussion texts a relatively harder task.

For example, it is difficult to understand that the data presented in the particular analysis of Table 1 is related only with the curves of Figure 5 (CO2 production – at which temperature? Abiotic or biotic?) for an assumed 1^st order kinetics (and k may represent any kinetic order). In Figure 5 curves, referred in Table 1, which material is used? All the materials?

In the discussion, statements like “The k value had typical values for the composting process.” (line 279, page 9) are too vague. Is this based on which references?

It seems that the authors transfer a significant part of the task of interpreting the huge amount of experimental data gathered, to the reader, which does not seem to be a viable option, since this should be their major task.

So, despite the noticeable merits of the work, overall the paper is confusing especially in the presentation and discussion of the results. Therefore I suggest a better organization of the data presented and the related discussion. More data presented in Tables, for example, and less discussion descriptions related to fundamental values that need to be consulted and interpreted elsewhere.

Author Response

Our reply is in the attached file.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

I recommend that the manuscript be accepted.

Author Response

Thank you for your acceptance.

Reviewer 2 Report

The authors rewrote fragments of the manuscript for a more fluid reading. The improvements made increased the quality and presentation of the article for our readers. I recommend that the manuscript be accepted.

Author Response

Thank you for your acceptance.

Reviewer 3 Report

In the revised manuscript, the authors address satisfactorily the recommendations received. I appreciate the effort, and now, I invite the authors to check their work carefully before resubmission, particularly, in taking special consideration to the English proofreading that has been carried out. Anyway, I think that after this step the manuscript will be ready for acceptance.

Author Response

Thank you for your acceptance. The manuscript has been additionally corrected and improved.