Optimizing the In-Vessel Composting Process of Sugarbeet Dry-Cleaning Residue

Round 1

Reviewer 1 Report

The experimental work presented in the Manuscript Agriculture-1598025, entitled "Optimizing the In-Vessel Composting Process of Sugar beet Dry-Cleaning Residue" is interesting research with some promising results related with the influence of passive and active aeration systems for the aerobic composting of sugar beet residues. The article reports the effects of the aeration systems and the influence of additives and moistening in a factorial experimental design. Despite the interesting experimental and high automized system reported for the process, there are several shortcomings and modifications that should be included in order to enhance the final manuscript for the readers. Moreover, also English need some editing in terms of grammar and redaction.

Therefore, the manuscript must be handled back to the authors with major revisions or suggestions. Some specific suggestions as follow:

 

Abstract section

• Please refer to charcoal and manures as additives in a co-composting system if correspond.
• Line 21, there were no “several” parameters evaluated, please delete.

 

Introduction section

• Line 43, modify in efficient to inefficient.
• Line 47 to 51, please refer and explain the environmental impacts related to pyrolysis which is a highly efficient process according to literature for biomass transformation.
• Line 50 to 52, composting is a highly efficient process, however, and despite an adequate manage of the process, there are several environmental impacts related to GHG emission, odors, leaching and even the presence of some pollutant in final product (e.g., heavy metals) please, modify this statement.
• Lines 55 to 59, please improve redaction.
• Lines 75-76, please refer what vinasse is.
• Lines 89-90, please include more details related to the effect of non-properly C/N in chemical and biochemical properties of soil.
• Despite that one of the factors evaluated is the utilization of the additives such as charcoal, no details were provided in the introduction section. Include justification and what charcoal is. Authors are referring to biochar obtained by pyrolysis or another type or source of coal. Please include some antecedents.
• Describe the differences and advantages of aerated composting systems in this section.
• Include a Hypothesis in final paragraph.

 

Material and methods section

• There was an appropriate description of the operation in terms of the equipment functioning, however, the process of composting itself need some modification.
• Please include a table with the initial characterization of the different materials and mixtures composted
• How long the residues were dried, and which was the final moisture of the different feedstock.
• Please include the initial moisture or water content of the different compost mixtures
• Please provide antecedents about charcoal. How the charcoal was obtained or produced. Include characterization if it is possible.
• Lines 170- 177, authors are referring to organic matter (OM), organic carbon (TOC) or total carbon (TC) for calculation. Initial C/N ratio of mixtures must be provided, and the labs procedure referenced in order to avoid any confusion for readers.
• Include details about the experimental design, it is a completely randomized and multifactorial experimental design? please provide more antecedents.
• In section 2.4, water vapor distributed into the barrels was cooled in pipes or it was distributed at 100 ºC at every aeration and moistening procedure?
• Germination test was an incubation of soil and compost? Please indicate if the procedure was performed under greenhouse conditions, which type of soils was used (chemical characterization at least) and what the control treatment included (water?). It is possible to perform some germination test according to Zucconi?
• Authors must include statistical analysis sub-section. How many replications were considered for every parameter analyzed?
• For optimizing, a statistical model of multiple response optimization needs to be considered for a proper final analysis.

 

Results and discussion section

• In general, there are several results and some of them very interesting, but it was poorly discussed. For example, what represent the temperature patterns and profiles in terms of microbial activity, changes in pH and EC among others.
• Non stats were provided. In multifactorial design is necessary to provide the influence of every factor analyzed during the process. In this study and according to the objectives, the influence of moistening and the utilization of additives must be also measured in the analysis, and it was no considered in results and discussion section. Please include a proper analysis and discussion about the effect of coal and moistening procedures.
• Please provide antecedents of final product, there were a reduction in terms of volume or mass? How was the stabilization measured?
• Why the temperatures did not achieve thermophilic phase. This is a critical aspect to be considered in a composting procedure in terms of microbiological succession, biochemical reactions (accordingly to literature, lignocellulose is mainly decomposed by thermophilic microorganisms) and related to the elimination of pathogens. It must be also discussed.
• Treat 3 showed the lower reduction in terms of moisture, could be related to the addition and properties of charcoal, please discuss.
• Figures, please provide error bars
• Tables include SD

Author Response

Reviewer 1

The experimental work presented in the Manuscript Agriculture-1598025, entitled "Optimizing the In-Vessel Composting Process of Sugar beet Dry-Cleaning Residue" is interesting research with some promising results related with the influence of passive and active aeration systems for the aerobic composting of sugar beet residues. The article reports the effects of the aeration systems and the influence of additives and moistening in a factorial experimental design. Despite the interesting experimental and high automized system reported for the process, there are several shortcomings and modifications that should be included in order to enhance the final manuscript for the readers. Moreover, also English need some editing in terms of grammar and redaction.

Therefore, the manuscript must be handled back to the authors with major revisions or suggestions. Some specific suggestions as follow:

 Response: We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript.

Abstract section

• Please refer to charcoal and manures as additives in a co-composting system if correspond.

Response: many thanks for comment. Yes sure; we refers to both charcoal and manures as additives in the abstract of the revised manuscript (line 21)

• Line 21, there were no “several” parameters evaluated, please delete.

Response: many thanks for comment. Yes you are right they are just a few parameters. We have modified it in the revised manuscript (Line 22).  

Introduction section

• Line 43, modify in efficient to inefficient.

Response: many thanks for comment.  It has been modified in the revised manuscript (Line 44) 

• Line 47 to 51, please refer and explain the environmental impacts related to pyrolysis which is a highly efficient process according to literature for biomass transformation.

Response: many thanks for comment. we mentioned the environmental impacts of pyrolysis as an effective procedure mentioned in many previous investigations in the revised manuscript (Line 49-51). 

 

• Line 50 to 52, composting is a highly efficient process, however, and despite an adequate manage of the process, there are several environmental impacts related to GHG emission, odors, leaching and even the presence of some pollutant in final product (e.g., heavy metals) please, modify this statement.

 

• Lines 55 to 59, please improve redaction.

Response: many thanks for comment. It has been modified in the revised manuscript (Line 56-59).

 

• Lines 75-76, please refer what vinasse is.

Response: many thanks for comment. Thanks, vinasse is a liquid by-product of the fermentation and distillation of molasses liquid a sugar mill by-product of. This was added to the revised manuscript (line 80-81).

 

• Lines 89-90, please include more details related to the effect of non-properly C/N in chemical and biochemical properties of soil.

Response: many thanks for comment. Micro-organisms will be deprived from nitrogen that are essential for oxidizing excess nitrogen and consequently will compete with plants to consume soil-soluble nitrogen (Line 97-99).

 

• Despite that one of the factors evaluated is the utilization of the additives such as charcoal, no details were provided in the introduction section. Include justification and what charcoal is. Authors are referring to biochar obtained by pyrolysis or another type or source of coal. Please include some antecedents.

Response: many thanks for comment. Charcoal is mainly produced from pyrolysis of wood was used as a bulking agent to help aerating composting mass because most of it contains clay mineral so the pore-space would be blocked with moistening.

 

• Describe the differences and advantages of aerated composting systems in this section.

Response: many thanks for comment. Good, in the revised manuscript the advantages of aerating composting mass have been mentioned (Line 102-104).

 

• Include a Hypothesis in final paragraph.

Response: many thanks for comment. The hypothesis of our research was that compost quality can be enhanced through choosing the proper aeration method, adding additives and moistening which is mentioned in the (Lines: 108-109). 

 

Material and methods section

• There was an appropriate description of the operation in terms of the equipment functioning, however, the process of composting itself need some modification. Please include a table with the initial characterization of the different materials and mixtures composted

Response: many thanks for comment. Various characteristics of DSR at the beginning of the experimental work (before composting) are listed in table 2. The C/N ratio on the first day was unified to be 28 where the differences between the mixture was not noticeable where no noticeable degradation occurs to manure or charcoal.

 

• How long the residues were dried, and which was the final moisture of the different feedstock.

 

• Please include the initial moisture or water content of the different compost mixtures

Response: many thanks for comment. The initial moisture or water content of different mixture was measured at the beginning of day 9 as depicted in Figure 6

 

• Please provide antecedents about charcoal. How the charcoal was obtained or produced. Include characterization if it is possible.

Response: many thanks for comment. The charcoal was brought from a local charcoal kiln which is mainly produced using pyrolysis of woody material.

 

• Lines 170- 177, authors are referring to organic matter (OM), organic carbon (TOC) or total carbon (TC) for calculation. Initial C/N ratio of mixtures must be provided, and the labs procedure referenced in order to avoid any confusion for readers.

Response: many thanks for comment. The lab procedure of determining the C/N ratio was performed according to FCQAO and BGK, 2003 which has mentioned in the materials and methods section (Lines 262)

 

• Include details about the experimental design, it is a completely randomized and multifactorial experimental design? please provide more antecedents.

Response: many thanks for comment. Yes you are right the experimental design was set as a completely randomized and multifactorial. It has been mentioned in the materials and methods section under section 2.7. Statistical analysis from (Lines 287-288)

 

• In section 2.4, water vapor distributed into the barrels was cooled in pipes or it was distributed at 100 ºC at every aeration and moistening procedure?

Response: many thanks for comment. it was modified  (line 222- line 223).

 

• Germination test was an incubation of soil and compost? Please indicate if the procedure was performed under greenhouse conditions, which type of soils was used (chemical characterization at least) and what the control treatment included (water?). It is possible to perform some germination test according to Zucconi?

Response: many thanks for comment. Thanks for your recommendation but there are several advantages of the method reported by Kader (2005). From many previous investigations, this method is reliable and easy in terms of the procedure.

 

• Authors must include statistical analysis sub-section. How many replications were considered for every parameter analyzed?

Response: many thanks for comment. Statistical analysis sub-section was added from line 284 with explanation the number of replications.

• For optimizing, a statistical model of multiple response optimization needs to be considered for a proper final analysis.

Response: many thanks for comment. Thanks very much for your recommendation. Optimization using statistical model of multi response has been performed and described in materials and methods section and the results are detailed as well in the results section under subtitle 3.8. Optimization Results line 501

Results and discussion section

• In general, there are several results and some of them very interesting, but it was poorly discussed. For example, what represent the temperature patterns and profiles in terms of microbial activity, changes in pH and EC among others.
• Response: many thanks for comment. We have support the results by discussing them by added new information for every section. As well as we added newly data such as Table 5. Concerning correlation between composting mass parameters in some days and temperature uniformity coefficients in the same days was listed in Table 5 where the highest correlation was found between temperature uniformity coefficient and C/N in days 17 and 33 of composting where it was 0.958 and 0.790, respectively while it was 0.744 between temperature uniformity coefficient and pH in day 25 of composting

 

• Non stats were provided. In multifactorial design is necessary to provide the influence of every factor analyzed during the process. In this study and according to the objectives, the influence of moistening and the utilization of additives must be also measured in the analysis, and it was no considered in results and discussion section. Please include a proper analysis and discussion about the effect of coal and moistening procedures.

 

Response: many thanks for comment. To test the impacts of active and passive aeration, coal manure and moistening procedures on C/N, EC, PH, MC and GI of final compost, the analysis of variance (ANOVA), appropriate for multifactorial design, was used. To compare the differences between the mean values of the C/N, EC, PH, MC and GI between the treatments, Duncan’s test at a p ≤ 0.01 and 0.05 significance level was applied.  We have explained in material and methods from the line 284 to line 290. As well the statistical Analyses of C/N, EC, PH and MC were added in Table 2 as well as statistical Analyses Germinated seeds were added in Table 3

Please provide antecedents of final product, there were a reduction in terms of volume or mass? How was the stabilization measured?

Response: many thanks for comment. Unfortunately the change in volume of mass was not tracked during the experimental work.

 

• Why the temperatures did not achieve thermophilic phase. This is a critical aspect to be considered in a composting procedure in terms of microbiological succession, biochemical reactions (accordingly to literature, lignocellulose is mainly decomposed by thermophilic microorganisms) and related to the elimination of pathogens. It must be also discussed.

Response: many thanks for comment. It was discussed from line 303 to line 313 under section (3.1. Temperature-Time Profile).

 

• Treat 3 showed the lower reduction in terms of moisture, could be related to the addition and properties of charcoal, please discuss.

Response: many thanks for comment. It was discussed from line 381 to line 384 under section (3.3. Moisture Content of Compost) 

 

• Figures, please provide error bars

Response: many thanks for comment. The value of error bars are very small and are not clear good above the columns. For that we did not added the values.

 

• Tables include SD

  Response: many thanks for comment. The SD values of Carbon to Nitrogen ratio, EC, PH and  moisture content were added in Table 2 as well as GI or SD values  of Germinated seeds was added in Table 3.

Author Response File: Author Response.docx

Reviewer 2 Report

- First sentence in abstract is not necessary.
- Line 53: Sugar beet
- Introduction should be thoroughly revised to provide consistency.
- Line 128: required
- Line 153: Element
- Leave space between data and units of measurement.
- No discussion in 3.1, 3.5, 3.6 or 3.7.
- I recommend using the germination index as standardized by Zucconi et al., 1981 (Biocycle 22: 54-57).
- Structure the conclusions in a short and clear paragraph (some, such as 4, do not contribute anything as a conclusion).

Author Response

Reviewer 2

 Response: We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript.

- First sentence in abstract is not necessary.
Response: many thanks for comment. The sentence has been rewritten again to be more informative.

- Line 53: Sugar beet
Response: many thanks for comment. You are right; the word has been corrected in the revised manuscript

- Introduction should be thoroughly revised to provide consistency.
Response: many thanks for comment. The introduction was revised and improved.

- Line 128: required
Response: many thanks for comment. You are right; the word, required, has been corrected in the revised manuscript.

- Line 153: Element
Response: many thanks for comment. The word, element, has been corrected in the revised manuscript

- Leave space between data and units of measurement.
Response: many thanks for comment. We went through the whole manuscript putting a space between data and units of measurements.

- No discussion in 3.1, 3.5, 3.6 or 3.7.

Response: many thanks for comment. Sections in 3.1, 3.5, 3.6 or 3.7 were discussed.

- I recommend using the germination index as standardized by Zucconi et al., 1981 (Biocycle, 22:54-57).

Response: Thanks for your recommendation but there are several advantages of the method reported by Kader (2005). From many previous investigations, this method is reliable and easy in terms of the procedure.

- Structure the conclusions in a short and clear paragraph (some, such as 4, do not contribute anything as a conclusion).

Response: Thanks for your comment. We re-structured the whole conclusions again to be precise and informative.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thanks to authors for the improvement of the article. There are several and significant changes included in the present form and most of my observations were clearify. However, I will insist in the need to include some properties and the origin of coal as additive in material and methods section. Therefore, I accept the manuscript with minor revisions.

Author Response

We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript.

Thanks to authors for the improvement of the article. There are several and significant changes included in the present form and most of my observations were clearify. However, I will insist in the need to include some properties and the origin of coal as additive in material and methods section. Therefore, I accept the manuscript with minor revisions.

Response: many thanks for comment. Additional information was added from line 205 to 208 as well as new table 1-C was added from line 225 under section (2.3. Experimental Design).

Author Response File: Author Response.docx

Reviewer 2 Report

I think the article has improved considerably after the arduous revision.

Author Response

We greatly appreciate your critical observations as well as your constructive and helpful comments.