Advanced Treatment of the Municipal Wastewater by Lab-Scale Hybrid Ultrafiltration
, Jelena Prodanović 2 and Ivana Ivančev-Tumbas 1
Xu Xia
Round 1
Reviewer 1 Report
The manuscript "Advanced treatment of the municipal wastewater by lab-scale 2 hybrid ultrafiltration" is well written but needs considerable revisions before it can be published. I recommend Major revisions.
1. Though the manuscript covers a very important problem, and tries to solve it using innovative solutions, but currently it has some drawbacks. here are some suggestions from my side.
2. Title needs substantial change, as currently it shows ultrafiltration only, but you have used other approaches as well.
3. Abstract: n this study, ultrafiltration with powdered activated carbon (PAC) 10 (dose 5 mg/L) separately or with coagulants was tested for the removal of ibuprofen, 11 caffeine and diclofenac from the municipal wastewater treatment plant effluent 12 (c0=2-3 µg/L), and it was additionally tested for removal of As, Cr, Cu and Zn 13 (c0~100 µg/L). Ferric chloride (FeCl3) (dose 4 mg Fe (III)/L) and natural coagulant isolated 14 from bean seeds (dose 33 µl/L) were applied. This needs to be changed. So haphazardly written.
4. "on metals and As content"- pls define abbreviation for the first time when used. Is As not a metal?
5. Lines 34-35 For majority of OMPs 34 content is not regulated by the legislation related to waste and surface water., not clear.
6.lines 53-58 The results of the 53 work of Marjanović et al. [1] show that it is possible to partially remove some metals and ?? As from real WWTP effluent even at low concentrations of about 100 µg/L if a natural coagulant isolated from bean seeds (23-52% zinc and 32 -39% As) or kaolinite (36–48% As) 56 are applied. In the same paper, it was confirmed that the hybrid process of coagulation/adsorption on kaolinite did not show any effect compared to separate processes., not clear.
7. Please rewrite your objectives, clearly defining the novelty of this paper and significant contributions to the field.
8.Table 1: please add a column for permissible limits of water for reuse for comparison. (For what purpose you are treating it?
9. Results are interesting but can be presented in a better way.
10. some figures are missing from the manuscript, for better description.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
A hybrid process combining powdered activated carbon and ultrafiltration, with the addition of coagulant was tested for the removal of organic and inorganic micropollutants. The paper is well structured and understandable.
It would be beneficial if a technological scheme or maybe a photo for the hybrid process is given. Also, although the process is on a laboratory scale, a lifetime estimate of the hybrid process should be given, with an estimate of investment and operating costs, in order that the hybrid process efficiency can be compared with similar water treatment processes or with different water treatment processes dealing with the same pollutants.
I recommend publishing the paper after these additions are made.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript sustainability-2343739 aimed to investigate the removal of ibuprofen, caffeine, diclofenac, As, Cr, Cu and Zn from the municipal wastewater treatment plant effluent by powdered activated carbon (PAC) separately or with coagulants.This study has some research value, however, there is an extensive description of comments to help the authors improve their work.
Detailed comments were listed as follows:
1. What is COA? Please clarify it.
2. Why is the dosage of PAC, FeCl3 and COA set at 5mg/L, 4mg/L and 33ul/L respectively?
3. How is the cycle defined here? Please elaborate on the conditions of the cyclein the Materials and Methods section
4. How did you add your PAC, FeCl3, and COA? Please explain in the Materials and Methods section
5. Is the choice for three times membrane filtration the same membrane or a brand new membrane of the same type? Please explain.
6. The results of three times membrane filtration show an increased tendency, please explain the reason.
7. All testing processes in Table 2 and 3 adopt the ultrafiltration technology. Do you need to supplement the use of PAC/FeCl3 or PAC/COA to demonstrate the outstanding contribution of UF process.
8. The impact of additives on ultrafiltration result has been explained in this paper, but what about their impact on the ultrafiltration process?
9. What is the impact of Line 355 EFOM? How does it affect?
10. The article provides corresponding analysis of ultrafiltration results. Why not explain in detail the role, mechanism of additives?
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Development of methods that can enhance the efficiency of ultrafiltration has relevance not just for the science but also for the practice. Combination of coagulation with ultrafiltration can be a viable option for the treatment of municipal wastewater. Authors deal with the applicability of UF with PAC technology and its combination with coagulation, as well. Removal efficiency as tested for organic micropollutants and metals, as well. Therefore, the topic of the manuscript can be considered as interesting for the readers. The manuscript is generally well structured. Introduction section summarizes well the relevance of the study. Applied methods are adequate. The manuscript contains interesting and valuable results.
Comments, suggestions:
PAC is not mentioned as key word.
Please provide standard deviation for data presented in tables and figures (see Table 1, Table 3, Figure 1, Figure 2, for instance).
Please provide the characteristics of natural coagulant derived from beans seeds as well.
Please give the pore size/cut off value of the applied membrane, as well.
Please give and discuss the molecular weight of the tested micropollutants, as well.
Please give the temperature applied during the filtration experiments.
Line 205-207 need reference(s) as well.
Y axis title is not visible in Figure 2.
Please discuss the practical applicability of the hybrid process in more details (potential for scale-up, most influential parameters, membrane-fouling problems using coagulants etc).
Author Response
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Author Response File: Author Response.pdf
Reviewer 5 Report
1. In data analysis section, it was not necessary to provide the equation to calculate the removal efficiency, because it was common knowledge.
2. The isolation or preparation method of natural coagulant from bean seeds should be given.
3. The author used rather low concentration of organic pollutants and heavy metal, however, the removal efficiency can not reach 100%. Could you further improve the removal efficiency, for example, using high dosage of PAC and coagulant, or extend the reaction time?
4. The highlight of this manuscipt was the use of a novel natural coagulant isolated from bean seeds, but the removal efficiency of natural coagulant was not ideal, which lowered the scientific significance of the article.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Can be accepted now!
Reviewer 3 Report
The author has made detailed replies to the review comments one by one, and made modifications in the corresponding places of the paper. The quality of the paper has been greatly improved.
