Bioleaching for the Removal of Arsenic from Mine Tailings by Psychrotolerant and Mesophilic Microbes at Markedly Continental Climate Temperatures

Round 1

Reviewer 1 Report

The manuscript "Bioleaching for the Removal of Arsenic from Mine Tailings by Acidithiobacillus Ferrivorans and Acidithiobacillus Ferrooxidans at MarkedlyContinental Climate Temperatures" reports bleaching at low temperature which is of considerable interest and can be accepted for publication after revision.

1. Is their any past literature available on low temperature bioleaching if so please cite some in the introduction.
2. The title of the manuscript can be rewritten omitting the names of the bacterial species.
3. The graphs should be reconstructed incorporating standard error bars.
4. The conclusion section should be rewritten mentioning only the specific concluding remarks and how the present study stands out from the already known facts which are published in the past.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper focuses on Arsenic removal from mine tailings which is a timely and important issue at a global scale.

As the authors say themselves it would be interesting to have a follow up evaluation of the chemical methods for the removal after the bio-leaching and potentially a life cycle assessment of the application of this method overall, its scalability and applicability.

Please find below in detail my comments on the paper

Lines 66/67 sentence unclear;

Lines 112/115 the authors recognise a gap of knowledge for bioleaching <10° however in their design of experiments only one of their tests is below that temperature, it would have been interesting to have tests at 8, 4 and 2 degrees maybe in order to ascertain the activity/yield changes in the less known range. The selected temperatures are within the ranges of the country under study, however they do not really fill the gap in the region unknown

Line 125 check spelling of words

Line 160 insert in bracket Jarosite formula for clarity please

Lines 170-172 the concentration of Arsenic is very low for the As-bearing phase scorodite to be visible in the XRD, is this identification certain? Was there any preparation/reconcentration done to the samples prior to analyses? If so could this please be referred to in the methodology section (above).

Fig. 2 can we improve the contrast/brightness so we can see morphologies and clarity of the images?

Lines 278-282 maybe a summary table showing the changes from Table 2 to Table 3 indicating the phase changes due to the bioleaching and in relation to the temperatures would be easier to read

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper is investigating the application of bioleaching for the Removal of Arsenic from Mine Tailings by Acidithiobacillus Ferrivorans and  Acidithiobacillus Ferrooxidans.  This is bringing novel information to a wider audience.

The authors of the study used the ICP-OES device for concentration analyzes. Unfortunately, the publication does not contain information on the use of CRM (certified reference materials), which is necessary when using the analyzes performed with this methodology.

Other minor remarks noticed during the review:

Line 60 “arsenian pyrite (FeS2)”, arsenic is missing in the formula

Line 158 “…. was adjusted to 1.6 using 10 N H2SO4”. – should be 10M H2SO4

Line 172  /173 muscovite 2M1 glicolated [(Si,Al)4O10(OH)2] - Does the wording 2 M 1 appear incorrectly?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I recommend the acceptance of the Manuscript.