Bio-Kinetics of Simultaneous Nitrification and Aerobic Denitrification (SNaD) by a Cyanide- Degrading Bacterium Under Cyanide-Laden Conditions

Round 1

Reviewer 1 Report

The extensive research will be instructive to especially to 

engineers in wastewater treatment plants.

However,  the content is rather redundant and should be refined. 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Some comments have been addressed regarding the previous submission.

The introduction is better now. 

However, the section on the results of different kinetic models still suffers from errors in writing. In many cases still the R2 values used for comparison are not corresponded to the values visible in the figures, specially for the rate law model. 

The paper still lacks any discussion on the presented results. This part is important for such a study and improves the significance of the research. 

English language still needs improvements. There are many grammatical errors still present in the text. 

 

 

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The comments have been addressed properly. 

some final English proofing is recommended. 

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

This article describes a bacterium that can nitrify and denitrify in the presence of cyanide. I have to point out the several issues on it.

It is unclear for me why the single bacterium conduct ammonia, nitrate and cyanide. This bacterium has slow reaction rate. Therefore, it would be better to use three types of bacteria that conduct nitrify, denitrify and cyanide degradation separately.

Line 20: a unit should be mass / biomass / time. The unit of biomass may be VSS, CFU or the number of genes.

Line 21: There is no reaction of NO3 oxidation.

Table 1 can be deleted. The information can be written in text.

In Figure 1, another biomass amount, e.g., VSS, CFU or the number of genes, should be used. The plots at zero hour should be included.

Reviewer 2 Report

The paper needs more details of experimental data. From the judgement of the kinetics, it is difficult to judge the best one among three kinetic models, considering experimental errors. 5 It is difficult to check it, because the symbols are almost same. Where can we judge aerobic denitrification? Cyanide can be removed easily by chemical method. Is this bacteria rally advantageous over chemical method?

     6.Error in equations are seen.

Reviewer 3 Report

the paper presents interesting topic. however, there are some comments to consider.

here are the comments:

lines 59-63: the originality and novelty of the paper is not very clear. is the purpose of the paper to study the mechanism by which CN- affects the nitrification/denitrification? if yes, then the paper is not certainly achieving that, instead it studies the effect of a specific microorganism on reducing CN- negative impacts and not the mechanism itself. this should be expressed clearly in the introduction. 

section 2.4. here the presentation of the kinetic models is not very comprehensive. some parameters are not described right after the equation in which they appeared for the first time. the section should be rephrased. 

line 161: Xs are the data points themselves and n is the number of data points. 

lines 200-214: some typing errors: line 208 0.906 should be replaced with 0.9706. line 210: 0.92 should be replaced with 0.9776 for Andrew's model?

Figure 3: why the Haldane model is far from good to predict the experimental data compared to linear model? is there any explanation for that? the predicted degradation rate vs observed ones shows better fit for Haldane instead.

Many times in the text Haldane model is written Heldane. should be corrected.

lines 231-250: many times the term band is used instead of peaks. band is referred to a range of wavelengths from the spectrum while peak is the high point at a specific single wavelength. should be addressed. 

Figure 5B: two lines are not distinguishable. better to used different colors to present. 

Figure 5: there is no NO3 in the figure but it is mentioned in the caption and in the text. is it always zero? 

the paper lacks any discussion and comparison of the significance of the results compared to other studies. for example: how high is it when we talk about highly CN- loaded wastewater? what do the other studies achieved in this context? 

the English language of the text should be checked carefully. there are many grammatical and punctuation errors in the text.