Nanofiltration Treatment of Industrial Wastewater Doped with Organic Dye: A Study of Hydrodynamics and Specific Energy

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Comments for Processes (2022.9.27.)

 Although the authors have made some corrections and modifications, the quality has no substantial improvement. The English is still not sound with numerous mistakes. Many sentences are confusing and misleading.

Interpretation for the pressure’s effect is not clear.

The conclusions is too wordy.

Some other particular flaws are listed as follows. 

Line	Original expression	Comments
26	municipal wastewater treatment stations (WWTP)	municipal wastewater treatment plant (WWTP)
52	been purified a municipal wastewater treatment plant	been purified in a municipal wastewater treatment plant
57	An increase the turbidity of the water	An increase in the turbidity of the water
57	degradation	deterioration
93	1.4 μm	1.4 nm
Table 1	UV254	absorbance at 254 nm
164	permeability of 8.97.10-6 m.s.bar	Is the unit correct?
175	wastewater dilution ratio with drinking tap water	Was the effect of the impurities in tap water considered?
Fig. 3		Why the results are so different from the previous version?
248	Optimal conditions were found for required water quality	It’s not clear if this sentence refers to the authors’ results or literature data. If it’s the former, what water quality does it mean here?
255-263		This paragraph is confusing!
Fig. 6	pression	pressure
Fig. 6	Reduction COD	Reduction of COD
347		How was the dilution factor defined?
351	retention rate of COD	Now that both the permeate and the retentate were circulated and collected in the same tank, how the retention rate was calculated?
377	which has a very complex ionic composition	The ionic composition was not characterized!

 Based on the above assessment, I suggest that the manuscript is still not meeting the requirement for publication in the journal.

 

Author Response

Thank you for your review of our paper, we have carefully reviewed the comments and we have revised the manuscript accordingly. Please see the attachment for the  responses to the Reviewer’s comments point by point (in red). All the suggested additions and/or corrections have been incorporated in the revised manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report (New Reviewer)

The manuscript entitled "Nanofiltration treatment of industrial wastewater doped with organic dye: Hydrodynamics study and Specific energy" submitted by Rokia Youcef et al. in Processes for publication needs to improve. The following points has to be fixed before to take the final decision as given below: (1) Introduction is written in very causal way, it should be improved by addition of some reported values to see the comparison with the present data. (2) Experimental details of the s of Instruments should be discussed with more clarity. (3) Font size should be uniformed throughout the manuscript. (4) No need of table as inset in figure 3. (5) Conclusion is very long, it should be concise.     

Author Response

Thank you for your review of our paper, we have carefully reviewed the comments and we have revised the manuscript accordingly. Please see the attachment for the  responses to the Reviewer’s comments point by point (in red). All the suggested additions and/or corrections have been incorporated in the revised manuscript.

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

Review of “Nanofiltration treatment of industrial wastewater doped with
organic dye: Hydrodynamics study and Specific energy” by Rokia Youcef, Nassila Sabba, Amel Benhadji, Hayet Djelal, Nadim Fakhfakh and Mourad Taleb Ahmed

The paper concentrates on experimental measurements of some characteristics of wastewater coming from a treatment plant and wastewater containing a dye undergoing a nanofiltration treatment. The manuscript lacks clarity in presenting certain aspects and should undergo major improvement in order to be published.

 

Some review comments are listed below:

 

1.     It is stated that the optimum operating parameters were determined by assessing the residence time distribution (RTD) in the reactor. Please identify the reactor on Figure1.

2.     Please state clearly what is the scope of RTD. At the beginning of the manuscript it is stated that the analysis was performed for optimization, however, the optimum working condition was established based on energy consumption. Also, please calculate the dispersion number or the Péclet number in order to discuss whether you have more dispersion or plug flow.

3.     Please provide some membrane characteristics in a table.

4.     You have different notations in equation (10) and Figure 3 for the permeate flux. Please correct! Please add a Notations section at the end for an easier follow.

5.     In Figure 7, a pressure increase by 5 times renders a 6% color removal increase. What was the pH. Can you present other data dependencies color removal depending on pressure for different pHs?

6.     Can you include any discussions related to your results if you had used another nanofiltration membrane?

7.     Please correct the “Donan effect” with the “Donnan effect”.

8.     Major English corrections are needed for a clear scientific message.

Comments for author File: Comments.pdf

Author Response

Thank you for your review of our paper, we have carefully reviewed the comments and we have revised the manuscript accordingly. Please see the attachment for the  responses to the Reviewer’s comments point by point (in red). All the suggested additions and/or corrections have been incorporated in the revised manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report (Previous Reviewer 1)

The quality has no significant improvement compared with the previous version. The English is still not sound and needs careful correction by a native speaker. The text needs careful edition. Adding that the work lacks scientific and technological novelty, I am not suggesting for publication in the journal.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

2^nd review of “Nanofiltration treatment of industrial wastewater doped with
organic dye: Hydrodynamics study and Specific energy” by Rokia Youcef, Nassila Sabba, Amel Benhadji, Hayet Djelal, Nadim Fakhfakh and Mourad Taleb Ahmed

 

The manuscript has been improved with the addition of some important required information and can be published after reconsidering some English mistakes.

Comments for author File: Comments.pdf

Author Response

The English has carefully revised. All correction were made in red in the manuscript.

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 manuscript “Treatment of industrial wastewater doped with organic dye by Nanofiltration process” talks about dye removal from industrial discharge and doped water by nanofiltration. Factors affecting the dye removal efficiency, including pH, hydrodynamic parameters and pressure, were studied experimentally. Overall, this is a very general work without considerable novelty for readers. The dye removal efficiency is not high. The text is not prepared clearly and some of the graphs are not prepared neatly. Based on my assessment of the quality, I suggest that it does not meet the requirement for publication in the journal. The following issues are to be addressed by the authors.

1.    The English is barely readable with numerous grammatical, spelling and type graphical mistakes and needs to be corrected by a native speaker.

2.    The title should be in title case.

3.    Analytical methods for the impurities in Table 1 should be clarified (each with a few words or short sentence), rather than just giving the standard code.

4.    Fig. 1: Are both of the permeate and retentate (wrong spelling in the manuscript) circulated? Where is the purified water collected?

5.    How was the tracer KCl analyzed?

6.    The terms in the equations and illustrations must be clarified.

7.    Page 218, citation is needed for Simpson method.

8.    The legend in Figure 4 is ghosting.

9.    Figure 5 has the results of dye removal from industrial discharge only, but the caption involves both industrial discharge and doped water.

10. Pages 310-311: “Also, we noticed that the removal of color increase with increase of transmembrane pressure to 84.05 %......” Under what pressure?

11. The smooth line in Figure 7 does not reflect the real experimental results.

12. Pages 326-329: The description is not clear.

13. Pages 330-331: The sentence was broken for no reason.

14. Figure 9: Now that the dye removal efficiency from raw water is higher than that from the doped water and it was assumed that this was due to the presence of matrix in raw water, the type of matrix and its effect mechanism should be further clarified.

15. The conclusions involve some common phenomena without new discovery.

16. Page 148: Potassium molybdate (K₂MnO₄). Potassium permanganate??

17. Page 158: polysulfobe. polysulfone ??

Author Response

Reviewer 1

Open Review

( ) I would not like to sign my review report

(x) I would like to sign my review report

English language and style

(x) Extensive editing of English language and style required

( ) Moderate English changes required

( ) English language and style are fine/minor spell check required

( ) I don't feel qualified to judge about the English language and style

Yes         Can be improved             Must be improved          Not applicable

Does the introduction provide sufficient background and include all relevant references?

(x)          ( )           ( )            ( )

Are all the cited references relevant to the research?

(x)          ( )           ( )            ( )

Is the research design appropriate?

(x)          ( )           ( )            ( )

Are the methods adequately described?

(x)          ( )           ( )            ( )

Are the results clearly presented?

( )           (x)          ( )            ( )

Are the conclusions supported by the results?

( )           (x)          ( )            ( )

Comments and Suggestions for Authors

This manuscript “Treatment of industrial wastewater doped with organic dye by Nanofiltration process” talks about dye removal from industrial discharge and doped water by nanofiltration. Factors affecting the dye removal efficiency, including pH, hydrodynamic parameters and pressure, were studied experimentally. Overall, this is a very general work without considerable novelty for readers. The dye removal efficiency is not high. The text is not prepared clearly and some of the graphs are not prepared neatly. Based on my assessment of the quality, I suggest that it does not meet the requirement for publication in the journal. The following issues are to be addressed by the authors.

 

1. The English is barely readable with numerous grammatical, spelling and type graphical mistakes and needs to be corrected by a native speaker.

It was done in the revised manuscript. The correction was made in red

2. The title should be in title case.

 It was done in the revised manuscript

3. Analytical methods for the impurities in Table 1 should be clarified (each with a few words or short sentence), rather than just giving the standard code.

The corrections were made between lines 159-161 

4. Fig. 1: Are both of the permeate and retentate (wrong spelling in the manuscript) circulated? Where is the purified water collected?

 The Cross-flow (also defined as tangential flow) filtration is conducted by employing Nanomax50 membrane with surface of 0.37 m ² with recycling permeate and retentate (which could be called the reject or concentrate) during treatment in order to keep a constant concentration, enhance the variation of permeate flux and preserve the uniform flow rate of permeate with necessity of make backwashing process after every treatment.  The purified water was collected  by taking samples at the end of the treatment which was in about 20 and it could be reduced by varying the different conditions (pH variation, operating pressure and dilution ration) and depend in wastewater composition (presence or absence of organic dye)

5. How was the tracer KCl analyzed?

We followed the concentration of the tracer KCl by conductimeter by determination of the calibration curve. We prepare differents solutions having a known concentration in KCl and determination of their conductivity then draw the curve to deduce Conductivity=f([KCl])

6. The terms in the equations and illustrations must be clarified.

It was done in the revised manuscript.

7. Page 218, citation is needed for Simpson method.

The correction was done in the line 229

8. The legend in Figure 4 is ghosting.

The correction was made in the manuscript

9. Figure 5 has the results of dye removal from industrial discharge only, but the caption involves both industrial discharge and doped water.

The correction was made in the manuscript between lines 306-308

10. Pages 310-311: “Also, we noticed that the removal of color increase with increase of transmembrane pressure to 84.05 %......” Under what pressure?

It was noticed that the removal of color increased with an increase of transmembrane pressure of 5 bar to 84.05 %. But take into consideration the increase of the specific energy with the increase of the pressure. The study demonstrate that the treatment of industrials wastewater could be by optimizing the specific energy consumption and applied the pressure of 4 bar and permeate flux of 407.03×10^-7 m/s.

 

11. The smooth line in Figure 7 does not reflect the real experimental results.

The correction was made in the figure 7, line 336

12. Pages 326-329: The description is not clear.

The clarification was made between 344-348

13. Pages 330-331: The sentence was broken for no reason.

The correction was made in line 348

14. Figure 9: Now that the dye removal efficiency from raw water is higher than that from the doped water and it was assumed that this was due to the presence of matrix in raw water, the type of matrix and its effect mechanism should be further clarified.

The treatment of industrial wastewater was in the presence and absence of organic dye (in wastewater), it was noticed that presence of dye in wastewater with high dilution ratio decrease the retention of organic dye due to increase of dye concentration may block the membrane pores and cause an increase in the membrane resistance (the membrane surface more compact)  for permeation with lowering the water flux because of the increase of the solution viscosity besides the raise in the concentration polarization onto the membrane surface. This could explain the obtained result.  The clarification was further explained between lines 357-363.

15. The conclusions involve some common phenomena without new discovery.

The correction was made in the manuscript between lines 405-444

16. Page 148: Potassium molybdate (K2MnO4). Potassium permanganate??

The product is a potassium molybdate K₂MoO₄, The correction is made in the line 147

17. Page 158: polysulfobe. polysulfone ??

The membrane are in polyamide polysulfone. The correction was made in line 162

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript has the following title “Treatment of industrial wastewater doped with organic dye by Nanofiltration process”. This study investigates to eliminate the ions and molecules present in industrial wastewater received by the municipal station of wastewater treatment (WWTP) of Reghaia located east of Algiers-Algeria. The results obtained prove that the influence of matrices through wastewater dilution with drinking tap water ratio (volume of wastewater: total treated volume) on Nanofiltration performance with a volume dilution ratio of 1/2 showed good performance in removing the chemical oxygen demand of 87.2 % after 15 minutes of filtration of the undoped wastewater. In General, I believe this research manuscript is straightforward and contains findings that would be of interest to other local/ international researchers. In general, the manuscript contains some serious flaws, which need to be considered. Before further processing of the manuscript. I’d like to recommend this manuscript for publication after resolving the minor issues noted below.

1.       More quantitative findings information should be provided in the abstract

2.       Line 30 and 33. Please use the correct format of unit m^{3 and} Remove extra space

3.       Please check the Keywords guidelines.

4.       Line 54-57. Please revised these lines, which have major grammar issues.

5.       Line 99. On the other hand, according to Sharjeel Waqas et al,… please cite the same reference

6.       Line 116-127. What is an innovation of this research?

7.       Line 135. Please explain, what is flac. Or full form?

8.       Line 139-141. “Table 1 with a high concentration of TDS can reach 1240 mg/l and the concentration of total nitrogen NT exceeds discharge standards.” This statement is totally confusing, which didn’t found in Table 1. Please explain it

9.       Please revise Figure 4. There is a major issue

10.   Please write more discussion about Fig 5.

11.   In section, 3.3.2. Effect of pressure, why author used only 1 to 5 bars of pressure? Why not up to 10 bars?

12.   In the result discussion  section, many sentences are too confusing and syntax issues please correct them

 

13.   It is suggested that the author can improve the conclusion 

Comments for author File: Comments.docx

Author Response

Reviewer 2

 

Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	(x)	( )	( )	( )
Are all the cited references relevant to the research?	(x)	( )	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	( )	(x)	( )	( )
Are the results clearly presented?	(x)	( )	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

Comments and Suggestions for Authors

The manuscript has the following title “Treatment of industrial wastewater doped with organic dye by Nanofiltration process”. This study investigates to eliminate the ions and molecules present in industrial wastewater received by the municipal station of wastewater treatment (WWTP) of Reghaia located east of Algiers-Algeria. The results obtained prove that the influence of matrices through wastewater dilution with drinking tap water ratio (volume of wastewater: total treated volume) on Nanofiltration performance with a volume dilution ratio of 1/2 showed good performance in removing the chemical oxygen demand of 87.2 % after 15 minutes of filtration of the undoped wastewater. In General, I believe this research manuscript is straightforward and contains findings that would be of interest to other local/ international researchers. In general, the manuscript contains some serious flaws, which need to be considered. Before further processing of the manuscript. I’d like to recommend this manuscript for publication after resolving the minor issues noted below.

1. More quantitative findings information should be provided in the abstract

The information was provided in the abstract in lines 36 to 41

2. Line 30 and 33. Please use the correct format of unit m^{3 and} Remove extra space

The correction was made in line 32

3. Please check the Keywords guidelines.

The keywords guidelines must be tree to ten keywords which need to be added after abstract and to be specific to the article, yet reasonably common within the subject discipline. The correction was made between lines 43 to 44

4. Line 54-57. Please revised these lines, which have major grammar issues.

The correction was made between lines 55 to 60

5. Line 99. On the other hand, according to Sharjeel Waqas et al,… please cite the same reference

The citation was added in article in line 100.

6. Line 116-127. What is an innovation of this research?

The novelty of this research was more explained between lines 111-125

7. Line 135. Please explain, what is flac. Or full form?

The flac Is the bottle used to take the sample, the correction was made in the line 139

8. Line 139-141. “Table 1 with a high concentration of TDS can reach 1240 mg/l and the concentration of total nitrogen NT exceeds discharge standards.” This statement is totally confusing, which didn’t found in Table 1. Please explain it

This expression has been added to give more details on the composition of wastewater and that the values of NT is very variable and  it exceeds the standards value  according to the results found by the laboratory of analysis of the WWTP and which is not analyzed during our study.

9. Please revise Figure 4. There is a major issue

The correction was made in line 296. Also, we noticed that the variation could not be presented in scatter plot presentation because of different chemical properties of membrane with change of the pH and the variation of the ionic charges of the wastewater in absence and presence of organic dye.

10. Please write more discussion about Fig 5.

The discussion was more detailed between lines 302-313

11. In section, 3.3.2. Effect of pressure, why author used only 1 to 5 bars of pressure? Why not up to 10 bars?

The pressure as a physical parameter studied could make the membrane process more efficient for the treatment of wastewater but increasing the pressure has a negative impact on the removal efficiency of organic dye due to allowing more dyes to pass through the membrane. Also, the study demonstrates that the increase of pressure increase a flux of permeate with high specific energy consumption.

12. In the result discussion  section, many sentences are too confusing and syntax issues please correct them

The correction was made in manuscript.

13. It is suggested that the author can improve the conclusion 

The correction was made in manuscript between lines 389-429

Author Response File: Author Response.docx

Reviewer 3 Report

This manuscript discusses a NF process for treating wastewater with dyes. However, the organization and logics are not good for publication in this journal.

1)       What does the residence time distribution mean? Here is no reactor for analysis.

2)       In the conclusion, “The study of the residence time distribution (RTD) leads to enhance energy consumption in term of dispersion, the flow approaches and velocity in the reactor. ” it cannot be supported by the work.

3)       The NF process consumes 75.08kWh/m3. It is too large to believe.

Author Response

Reviewer 3

 

This manuscript discusses a NF process for treating wastewater with dyes. However, the organization and logics are not good for publication in this journal.

• What does the residence time distribution mean? Here is no reactor for analysis.

The residence time distribution (RTD) is a very important concept in reactor engineering to characterize the performance of Nanofiltration process, to optimize the process operation conditions and an application examples include monitoring of hydrodynamic conditions, concentration polarization and fouling in membrane modules.

• In the conclusion, “The study of the residence time distribution (RTD) leads to enhance energy consumption in term of dispersion, the flow approaches and velocity in the reactor. ” it cannot be supported by the work.

A lot of study and researches were conducted to show the effect of the residence time distribution (RTD) as an innovative spacer designs when multiple elements are connected. Also, it presents great opportunity for avoid the fouling and scaling problems in the operation of membrane in higher flow which has a direct relation with the energy variation.

3)       The NF process consumes 75.08kWh/m3. It is too large to believe.

The scarcity of water (drought of 2022) is the best lesson to learn and put considerable efforts in water treatment. In addition, the solar photovoltaic in front of the climatic changes lead us to consider the photovoltaic electricity to allow us an acceptable water security in spite of the fact that the membrane process are an energy consuming.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

This manuscript “Treatment of industrial wastewater doped with organic dye by Nanofiltration process” talks about dye removal from industrial discharge and doped water by nanofiltration. Factors affecting the dye removal efficiency, including pH, hydrodynamic parameters and pressure, were studied experimentally. Overall, this is a very general work without considerable novelty for readers. The dye removal efficiency is not high. The text is not prepared clearly and some of the graphs are not prepared neatly. Based on my assessment of the quality, I suggest that it does not meet the requirement for publication in the journal. The following issues are to be addressed by the authors.

1.    The English is barely readable with numerous grammatical, spelling and type graphical mistakes and needs to be corrected by a native speaker.

2.    The title should be in title case.

3.    Analytical methods for the impurities in Table 1 should be clarified (each with a few words or short sentence), rather than just giving the standard code.

4.    Fig. 1: Are both of the permeate and retentate (wrong spelling in the manuscript) circulated? Where is the purified water collected?

5.    How was the tracer KCl analyzed?

6.    The terms in the equations and illustrations must be clarified.

7.    Page 218, citation is needed for Simpson method.

8.    The legend in Figure 4 is ghosting.

9.    Figure 5 has the results of dye removal from industrial discharge only, but the caption involves both industrial discharge and doped water.

10. Pages 310-311: “Also, we noticed that the removal of color increase with increase of transmembrane pressure to 84.05 %......” Under what pressure?

11. The smooth line in Figure 7 does not reflect the real experimental results.

12. Pages 326-329: The description is not clear.

13. Pages 330-331: The sentence was broken for no reason.

14. Figure 9: Now that the dye removal efficiency from raw water is higher than that from the doped water and it was assumed that this was due to the presence of matrix in raw water, the type of matrix and its effect mechanism should be further clarified.

15. The conclusions involve some common phenomena without new discovery.

16. Page 148: Potassium molybdate (K₂MnO₄). Potassium permanganate??

17. Page 158: polysulfobe. polysulfone ??

Author Response

Dear Reviewer, 

 

Thank you for your comments to improve our manuscript. We hope that the corrections that we made are sufficient.

Author Response File: Author Response.doc

Reviewer 3 Report

The energy consumption of NF in this study, I think, is incredible. 

Author Response

Thank you for your comments to improve our manuscript. We hope that the corrections that we made are sufficient.

Author Response File: Author Response.doc