Shear Enhanced Flotation Separation Technology in Winery Wastewater Treatment
Round 1
Reviewer 1 Report
The described research is interesting and relevant to the Journal’s scope. Details are adequate to fully understand the results. However, there are several general concerns.
The process was not optimized cost and energy usage regarding the amount and types of coagulants with the SEFS. Instead, a step-by-step approach was taken as compared to an iterative approach. Would it have been beneficial to use less air and/or mixing and use more chemicals or less chemicals and more intense mixing?
There is a lack of discussion on nitrogen and phosphorus. Would have been of great interest to understand more about the impact of the treatment process on nutrients. Refinement of conclusions is necessary to indicate that this is not an optimized process.
More details on how this research is unique would be useful. Several references seem to predict the conclusions.
Additional, specific comments follow.
· Lines 50-56: levels seem very high. Recommend examining additional references for studies that examined the characteristics in more detail.
· Line 78 and 84: where are these “local discharge regulations”. Manuscript should be suited for an international audience and not only applicable to a specific region.
· Lines 88-92: sentence is awkward – suggest simplifying.
· Line 128: more details on “thermal agitation and hydrodynamic drag” would have been useful.
· Lines 136-138: redundant, not needed.
· Lines 179-187: provide basis for selecting these coagulants.
· Equations 1 and 1.1: not needed for something as basic as concentration calculations.
· Lines 235-247: detailed description of method is not needed as a standard method with a reference is used.
· Table 1: wastewater values are very high, as the author states. Does this biases finding, resulting in it not being transferable to other wastes?
· Lines 322-323: redundant, not needed.
· Lines 338-356: interesting, good background but belongs in the Introduction section.
· Lines 406-413: comparing results to this study does not seem valid. Trying to do this relates to general comment concerning lack of optimization and understanding how each unit of the process relates to one another.
· Line 472: see previous comments concerning the lack of optimization.
· Conclusion: please provide more insight into the potential of this technology and needs for further study such as optimizing energy and chemical use. A comparison to other treatment options would also be useful.
Overall, the manuscript is well organized and well written.
Author Response
Please see the attached.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I would like to congratulate the authors for this great, exciting work.
It was a pleasure to finally read an article that has practical significance.
The figures and tables are clear and easy to interpret. The language of the work is understandable.
After editing the tables (1., 2., 3.) into place, the work would be even more attractive.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Well-designed and researched study. Well-written as well, but there are a few commas/wording/spelling that need to be taken care of:
lines 11, 36, 38, 347, 488
I think this data will be very useful.
I think this is ready to go, those mentioned small fixes are minor
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
The paper explores an interesting subject, yet there is the need to note certain limitations, namely:
1. The rotation speed of the mixer rotor (measured in rpm) is wrongfully defined as the shear rate of medium, which is actually produced in the medium volume and is measured in s-1. Though there does exist cubic dependency between these values, commonly accepted terminology should be used to name the physical parameters.
2. No clear reasoning has been offered to explain the fact that after mixing for five minutes, the Zeta-potential equilibrium value is dependent on the medium shear rate and even reaches its extremum. This is contradictory to the thermodynamic theory of adsorption. It might be attributed to the effects that in the process of suspension passing between the rotor and the stator of the impeller, some outside chemicals separated from the impeller material get into it.
This phenomenon deserves additional detailed study, for example, using mixers produced from various materials.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
