Oily Wastewater Treatment: Methods, Challenges, and Trends
, Italo José Batista Durval 2, Andréa Fernanda de Santana Costa 3 and Leonie Asfora Sarubbo 2,4,*Round 1
Reviewer 1 Report
- From my point of view, not all the most interesting cleaning methods are listed in this article.
- Sorption cleaning methods are not marked
- At least approximate concentrations and compositions of effluents for specific treatment methods are not given.
- Possible combination methods and their results are not given.
- The conclusions are incomplete.
- the introduction also needs to be improved in connection with the above remarks.
Other than that, a pretty interesting review.
Author Response
Comments and Suggestions for Authors
- From my point of view, not all the most interesting cleaning methods are listed in this article.
Response: Dear reviewer, we understand your point of view and this is a good question. Our aim in the review was to focus on the most commonly used methods by the industry. We also aimed to mention interesting biotechnological methods that can be used in the near future, such as filtration with bacterial cellulose membranes. We hope the reviewer can understand.
2. Sorption cleaning methods are not marked
Response: A new section was created (4.6. Sorption cleaning methods) with information of sorption cleaning methods. Thank you for the remark.
3. At least approximate concentrations and compositions of effluents for specific treatment methods are not given.
Response: As oily effluents can have several compositions, it was very difficult to reach concentrations and compositions for the technologies described in the review. Thus, we focused on effluents in a general manner, instead of narrowing to specific kinds of oily effluents.
4. Possible combination methods and their results are not given.
Response: this is also a good question. As mentioned above, oily effluents can have several compositions, therefore, the number of treatment combinations methods can be enormous. We decided to focus on the methods separately but emphasising the possibility of combining methods depending on the need. We hope the reviewer understand.
5. The conclusions are incomplete.
Response: The conclusions were improved, as requested. Thank you for the observation.
6. The introduction also needs to be improved in connection with the above remarks.
Response: The introduction has also been written taking into consideration the remarks raised by the reviewer.
Other than that, a pretty interesting review.
Response: We really appreciate all your suggestions! We feel that the quality of the manuscript has improved after revision.
Reviewer 2 Report
The manuscript highlights the general methods used by industries for treatment of oily wastewater, it also discusses some novel biotechnological solutions, overall it is well written and is technically sound, I recommend its publications after some minor additions.
Here are some points to further strengthen it:
- In section 4.4, coagulation(flocculation) discuss about the different chemicals/polymers used as coagulants and their chemistry in oily wastewater.
- In the membrane separation technology section, the authors should add a discussion on membrane fouling in wastewater treatment and its consequences on the overall process.
- Based on the type of oil in wastewater (free floating, emulsified, dispersed, dissolved), the authors should conclude with the type of treatment methods suitable for each type and why other methods aren't that suitable.
Author Response
Comments and Suggestions for Authors
The manuscript highlights the general methods used by industries for treatment of oily wastewater, it also discusses some novel biotechnological solutions, overall it is well written and is technically sound, I recommend its publications after some minor additions.
Here are some points to further strengthen it:
- In section 4.4, coagulation(flocculation) discuss about the different chemicals/polymers used as coagulants and their chemistry in oily wastewater.
- In the membrane separation technology section, the authors should add a discussion on membrane fouling in wastewater treatment and its consequences on the overall process.
Response: As requested, the discussion of the topics mentioned above (1 and 2) have been improved. Thank you for the kind recommendation.
3. Based on the type of oil in wastewater (free floating, emulsified, dispersed, dissolved), the authors should conclude with the type of treatment methods suitable for each type and why other methods aren't that suitable.
Response: As there are several types of oily effluents, if we focused on describing each treatment method suited for specific oil compositions, the paper would become very extensive. For this reason, it was decided to focus on emulsified oily effluents and to mention the most commonly used methods for this type of effluent by the industry. We appreciate your output and we will consider it for future works.
Reviewer 3 Report
This review paper (Ref. No. 1681094) deals to describe and compare different methods of treating oily effluents currently used by the industry, discuss the advantages and disadvantages of tradition and new trends in the treatment of oily wastewater. This is an interesting and actual topic. There are 124 articles in the manuscript which were published in the last 20 years.
Overall, my evaluation is positive, and I believe that the manuscript can be published in Processes, but the minor revision is recommended before publication. Some specific comments are as follows:
1) There are 15 articles-reviews in the manuscript. It should be explained the works novelty of your article-review.
2) Introduction needs improvement. It should be used the bibliometric method to analyze the importance of this topic, which is a piece of statistical evidence. This is better than just summarizing all related papers.
3) It should be deleted double number 77 in References.
Comments for author File: 
Comments.pdf
Author Response
Comments and Suggestions for Authors
This review paper (Ref. No. 1681094) deals to describe and compare different methods of treating oily effluents currently used by the industry, discuss the advantages and disadvantages of tradition and new trends in the treatment of oily wastewater. This is an interesting and actual topic. There are 124 articles in the manuscript which were published in the last 20 years.
Overall, my evaluation is positive, and I believe that the manuscript can be published in Processes, but the minor revision is recommended before publication. Some specific comments are as follows:
1) There are 15 articles-reviews in the manuscript. It should be explained the works novelty of your article-review.
Response: The aim of the article was to describe traditional treatment methods for oily effluents, focusing on oily emulsions and possible biotechnological oily treatment processes. The novelty of our work is the focus point on emulsified effluents and biotechnological methods that have the potential of being a more sustainable alternative to be used by the industry (which is a different approach from the other review articles that were cited). The novelty was clarified in the introduction section, as suggested. Thanks.
2) Introduction needs improvement. It should be used the bibliometric method to analyze the importance of this topic, which is a piece of statistical evidence. This is better than just summarizing all related papers.
Response: Thank you for the observation. The introduction has been improved. Our intention in writing this article review was to carry out a compilation of concepts and results from relevant articles, in order to gather specific treatment information for researchers and companies interested in the topic. Therefore, the articles mentioned were chosen by our critical point of view as those that presented efficient results, but also with updated data, according to the subject proposed by the article. No specific statistical method was used.
3) It should be deleted double number 77 in References.
Response: Reference number 77 has been corrected. Thanks.
