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Concept Paper
Peer-Review Record

Evaluation of a Minimum Liquid Discharge (MLD) Desalination Approach for Management of Unconventional Oil and Gas Produced Waters with a Focus on Waste Minimization

Water 2021, 13(20), 2912;
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Reviewer 3: Anonymous
Water 2021, 13(20), 2912;
Received: 12 August 2021 / Revised: 12 October 2021 / Accepted: 13 October 2021 / Published: 16 October 2021
(This article belongs to the Section Wastewater Treatment and Reuse)

Round 1

Reviewer 1 Report

This paper put forward a concept of MLD and evaluate the feasibility it in PWs treatment. The concept was valuable for the engineering application. Meanwhile, the structure and language of this manuscript was good, and the data was well-explained. So, it was recommend for minor revise of this manuscript before publication, main questions and commends are as follows:

  1. The use of unit is not scientific in the whole paper, international standard units are recommended
  2. The introduction was too long, need further shorten and refine. And commonly,  no need for secondary headings in Introduction part.
  3. For OLI modelling, it was said "Imbalances in cations and anions were adjusted by the addition of sodium and chloride ions, respectively, to ensure an electrically neutral solution", is this method suitable or commonly used? It was said Cl had good correlation with the recovery in figure 3,  would it affect the results as if Cl is added?
  4. In the whole paper, I did not know exactly which type of technology is used for desalination? Please point it out?
  5. For the MLD, for example line136-139, the precipitation would happen even under the designed recovery, especially when the composition was considered, so is the selective standard of this work accurate?  Please make it clear.
  6. Figure 4, the difference of the salt composition is the key for the bad correlation of the waste and PW TDS, so I think the selective MLD should be updated? The composition should be considered.
  7. How to treat of the Liquid Waste in MLD? Inject to SWD wells is not a final solution. And this is the advantage of ZLD, it should also mentioned in the comparison, not just compare the advantages aspect of MLD.

Author Response

Please see attachment. 

Author Response File: Author Response.docx

Reviewer 2 Report





Evaluation of a Minimum Liquid Discharge (MLD) Desalination Approach for Management of Unconventional Oil & Gas Produced Waters with A Focus on Waste Minimization



G. L. Ghurye






In this manuscript, the author suggests a new approach of using MLD for processing unconventional PW. Then this modified MLD proposed is compared with ZLD in terms of several key parameters which include percentage of distillate recovered, liquid waste generated, solid waste generated, types of solid waste generated and compare the ease of processing this wastes generated in MLD and ZLD. 

Briefly, the new method is MLD, but author proposes to stop MLD before precipitation of Nacl, which happens at the evaporation point. This helps in reducing the soluble solid waste generated which is hard to dispose. The TDS and flowrate data from 83 wells in NM was supplied to OLI software to develop correlation between TDS and percentage of distillate recovered. Results suggest that high TDS of PW leads to low recovery and low waste generated. High recovery of distillate is possible at low TDS of PW.  Later, in the attempt to reduce the costs of desalination, high flow rate wells were selected as second step. Further the analysis was refined to only low TDS wells and high flowrate wells. The normalized results indicate that the subset of low TDS and high flowrate wells are the best way to get good recovery of distillate while also reducing the solid waste. 

Next steps that are required to lead to commercialization of this concept have also been laid out very well. There is need for validating this concept by conducting bench scale/pilot scale studies to verify the results from OLI software related to the correlations developed between TDS and distillate recovery %. This is specific to NM, so this type of study should be conducted in other regions as well.

The paper is well written, with well presented results that provide a clear validation of the proposed concept. Given the novelty of this concept I believe it is suitable for publication


Other Comments:

  1. Some references in similar field can be cited here, so that reviewers can follow and understand the work previously done in literature
  2. The figures could be rearranged to be present closer to the text in the body where the figure is references.

Author Response

Please see attachment. 

Author Response File: Author Response.docx

Reviewer 3 Report

This paper presents a worth topic investigation.  TBut there are some issues have to be addressed before accepting:

  • The literature review should be organized in a better format; I would suggest you use table summarizes findings from the literature review. The more related paper needed to reviewed
  • Some implication or data support from theory and test is highly recommended, but not necessary, but at least discuss it in the paper.
  • Limitation of this and method needed to be addressed and discussed
  • The future plan or suggestion is highly recommended.
  • some related highly recommended to be reviewed and cited.
  • 2019, Feasibility study of improved unconventional reservoir performance with carbonated water and surfactant, Energy, 182, 135-147
  • 2015, Evaluating sweep efficiency in flooding process of reservoir development using substitution index, The International Journal of Oil, Gas, and Coal Technology, 9(1), pp.1-13

Author Response

Author Response: I regret to inform the reviewer that I did not find the review comments to be pertinent/relevant to the study paper. Therefore, I cannot address any of these comments.

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