Bioremediation of PAH-Contaminated Soils: Process Enhancement through Composting/Compost
Round 1
Reviewer 1 Report
The authors reviewed bioremediation technologies (compost addition and composting) in soils contaminated with PAHs.
The manuscript is easy to read, but it requires moderate revision for grammar and syntax. Some examples: L52 (biotic, several misuses of the comma), L89 (replace "terrestrials" by "land"); L108-110; 116-125 (long and confusing sentences; replace "can't" by "cannot"); L148 (avoid "etc" in a scientific paper - suggest "among others"), L243 (...were "decrease of by"...should be written "decreased by" or "a decrease of"; L264: space underscored)
It is important to clarify (and distinguish) two concepts that are often misused throughout the manuscript: pollutant and contaminant. Please reconsider revision.
The applied structure for this review could be more clear. There are several topics within section 4: Bioremediation of PAH-contaminated soils by composting that leads to misinterpretation. It could be interesting to organize the review in a more clear way for not so experienced readers (in the bioremediation topic): i) PAHs - physicochemical properties, factors affecting their bioavailability and degradability in soil compartments, ii) bioremediation of PAH-contaminated soils: in-situ vs ex-situ technologies (or compost addition vs composting), discussing the major challenges and achievements of each one.
The review meets the scope and research needs of the journal.
Author Response
Reviewer # 1:
The authors reviewed bioremediation technologies (compost addition and composting) in soils contaminated with PAHs.
The manuscript is easy to read, but it requires moderate revision for grammar and syntax. Some examples:
L52 (biotic, several misuses of the comma)
It has been corrected
L89 (replace "terrestrials" by "land")
The word "terrestrials" has been replaced by "land" in the revised version.
L108-110; 116-125 (long and confusing sentences; replace "can't" by "cannot"
The sentence has been rewritten to be more easy for readers. Also "can't" has been replaced by "cannot"
L148 (avoid "etc" in a scientific paper - suggest "among others")
It has been modified as suggested by the reviewer
L243 (...were "decrease of by"...should be written "decreased by" or "a decrease of"
It has been corrected using "decreased by" as suggested by the reviewer
L264: space underscored)
The underscored space has been remove
It is important to clarify (and distinguish) two concepts that are often misused throughout the manuscript: pollutant and contaminant. Please reconsider revision.
We agree with the reviewer regarding the two concepts, however, both have been used as in some cases the concentrations of the PAHs below laws and regulations thresholds, and in other cases it was higher these thresholds, thereby, the two concepts have to be used.
The applied structure for this review could be more clear. There are several topics within section 4: Bioremediation of PAH-contaminated soils by composting that leads to misinterpretation. It could be interesting to organize the review in a more clear way for not so experienced readers (in the bioremediation topic): i) PAHs - physicochemical properties, factors affecting their bioavailability and degradability in soil compartments, ii) bioremediation of PAH-contaminated soils: in-situ vs ex-situ technologies (or compost addition vs composting), discussing the major challenges and achievements of each one.
We respect the reviewer point view, however, when the structure of the manuscript was developed, we took into our considerations to present the information in a simple and easy way. From our experience in this field, we believe that the current structure and form of the manuscript is suitable for all readers.
The review meets the scope and research needs of the journal.
Reviewer 2 Report
The paper “The application of composting/compost as a 3 bioremediation approach for PAHs-contaminated” provides a deep revision about the potential uses of compost to bioremediate contaminated soils. It is not a new problem and it is on the table for a long time and compost and its biodiversity has been around the problem as possible solution. I would recommend it for publication in the journal due there is a huge revision work that it should be all together The collected information should be very helpful to deep on potential solution for new researchers interested to bring into decontamination. I could divide the paper in two main parts, the first very general that it can found in any book, and it brought some Figures and Tables. The second part, that it is the hard part and the interesting one, is well written but I would suggest as general consideration to authors, they could do the effort to include some comprehensive Tables where the information that it is on text, could be summarized on a quick look. I also miss a figure related to the different pathways and then it would be helpful to refer when it is reviewing the effect of microorganisms.
The paper could also improved by taken into account the minor revision that are listed:
Line 41 “In any case, composting innovation as a remediation approach has been considered a reasonable innovation” It is not an innovation it ihas been produced in at least the last 20 years
Line 43 , on the other hand, CHANGE BY ;
Line 46
“normal composting process or compost addition”. It is confusing and wrong expressed. It should say to incorporate PAH contaminated soil to the composting process or by adding compost to contaminated sites
Line 48
While 48 biodegradation of PAHs in soil composting mixture depends intrinsically on the microbial activity, where bacteria and fungi are conisdered as the main pollutant-degrading foremost vital variables governing the soil remediation of contaminated soils [35-37].
Line 52
Biotic
Line 54
Delete last sentence
Line 99.
legend at the botton of the figure
Line 108 “can´t”
cannot
Line 317 Difficult sentence to be understood
Also, after 30 weeks, 317 the removal efficiencies of TPH in soils were 29.3 %, 82.1 %, 63.7 % and 90.2 % in the cases of natural 318 attenuation, nutrient addition (with NH4NO3 and K2HPO4), supplement with 20% (w/w, dry weight 319 basis) of aged refuse and the combination of nutrient and aged refuse
Line 360 Change to
Experiments with different ratios of contaminated soil to green waste from 0.6:1 to 0.9:1 demonstrated that in general PAH removal was significantly enhanced in reactors increased with green waste till a maximum of 0.7:1 [89].
Line 372 it should write in a sense point of view. The first sentence is vague and it should be followed by the obtained results for the authors.
Author Response
Reviewer # 2:
The paper “The application of composting/compost as a 3 bioremediation approach for PAHs-contaminated” provides a deep revision about the potential uses of compost to bioremediate contaminated soils. It is not a new problem and it is on the table for a long time and compost and its biodiversity has been around the problem as possible solution. I would recommend it for publication in the journal due there is a huge revision work that it should be all together The collected information should be very helpful to deep on potential solution for new researchers interested to bring into decontamination. I could divide the paper in two main parts, the first very general that it can found in any book, and it brought some Figures and Tables. The second part, that it is the hard part and the interesting one, is well written but I would suggest as general consideration to authors, they could do the effort to include some comprehensive Tables where the information that it is on text, could be summarized on a quick look. I also miss a figure related to the different pathways and then it would be helpful to refer when it is reviewing the effect of microorganisms.
A new figure showing the degradation pathway has been included to the revised manuscript.
We agree that tables and figures give quick look for readers about the results, however, due to the different variable for each research that has been discussed in this review, it would be difficult to arrange these information in tables, for that reason we tried to present the information in a suitable and easy for readers.
The paper could also improve by taken into account the minor revision that are listed:
Line 41 “In any case, composting innovation as a remediation approach has been considered a reasonable innovation” It is not an innovation it ihas been produced in at least the last 20 years
We agree with the reviewer concerning the point, accordingly, the sentence has been rewritten in a new form suing the word “approach” instead of “innovation”
Line 43 , on the other hand, CHANGE BY ;
“on the other hand” has been changed by “simultaneously”
Line 46
“normal composting process or compost addition”. It is confusing and wrong expressed. It should say to incorporate PAH contaminated soil to the composting process or by adding compost to contaminated sites.
The sentence has been rewritten as indicated by the reviewer
Line 48
While 48 biodegradation of PAHs in soil composting mixture depends intrinsically on the microbial activity, where bacteria and fungi are conisdered as the main pollutant-degrading foremost vital variables governing the soil remediation of contaminated soils [35-37].
The sentence has been corrected and rewritten in a suitable form
Line 52
Biotic
The misspelling mistake was mentioned by the reviewers, and it has been corrected
Line 54
Delete last sentence
The sentence has been deleted
Line 99.
legend at the botton of the figure
We totally agree. In the original word file, the legend of the figure was at the bottom, an error might be happened during changing the file to PDF format
Line 108 “can´t”
cannot
It has been changed as indicated by the reviewers
Line 317 Difficult sentence to be understood
Also, after 30 weeks, 317 the removal efficiencies of TPH in soils were 29.3 %, 82.1 %, 63.7 % and 90.2 % in the cases of natural 318 attenuations, nutrient addition (with NH4NO3 and K2HPO4), supplement with 20% (w/w, dry weight 319 basis) of aged refuse and the combination of nutrient and aged refuse.
The sentence has been restructured and written to be more easy and understandable for readers
Line 360 Change to
Experiments with different ratios of contaminated soil to green waste from 0.6:1 to 0.9:1 demonstrated that in general PAH removal was significantly enhanced in reactors increased with green waste till a maximum of 0.7:1 [89].
The sentence has been corrected ad rewritten as indicated by the reviewer
Line 372 it should write in a sense point of view. The first sentence is vague and it should be followed by the obtained results for the authors.
The sentence has been restructured and written to be more easy and understandable for readers
Reviewer 3 Report
I have provided comments in the attached Pdf file. Please address the comments.
Please also consider rewriting the title of the manuscript.
Comments for author File: 
Comments.pdf
Author Response
Reviewer # 3:
I have provided comments in the attached Pdf file. Please address the comments.
Please also consider rewriting the title of the manuscript.
A new title for the manuscript has been suggested
“Bioremediation of PAHs-contaminated soils: process enhancement through composting/compost”
Comments in PDF file
- More information has been included in the introduction section that shows the efficiency of composting approach over other approached.
- The research focus on soil contamination in general, and to give an imagination about the magnitude of the problem, Europe was used as an example only.
- Bioaugmentation is explained in section 4.5 “The mechanism of this approach fundamentally depends on introducing exogenous microorganism strains that are characterized by their high capacity and diverse metabolic profiles in degrading the target contaminants”.
- The conclusion has been rewritten
Round 2
Reviewer 1 Report
The authors addressed all the issues.
Reviewer 3 Report
Please check the English language.
