Microcystis aeruginosa Removal and Simultaneous Control of Algal Organic Matter (AOM) Release Using an Electro-Flocculation–Electro-Fenton (EC-EF) System without Chemical Addition

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript demonstrates that the use of EC-EF system can be useful in reducing microcystins in water systems. Overall, I think the data are valuable, especially in terms of finding inexpensive and chemical-free methods to reduce microcystin concentration. However, there are many statements/sections that should be reevaluated, and I have several questions about the conclusions. Comments below:

Abstract

Line 12. Microcystis aeruginosa are a cyanbacterium, not an alga. This is repeated throughout that paper and should be changed from algae/algal.

Introduction

Lines 33-35. This sentence is confusing and combines many parts that were not previously discussed.

Line 41. What is meant by “low”?

Line 43. Does “poor in economics” mean costly?

Line 47. More attention from who?

Line 53. What does it mean to “deactivate” a cyanobacterium?

Line 57. Why is the time included here? Why is it important?

Lines 58-62. This sentence is confusing and combines too many ideas.

Line 66. So what? Why is this sentence important?

Line 71-72. Explain this more.

Line 97. Define BDD-CF, Pt/Ti-ACF/Ni, and Pt-GF

Materials and Methods

Section 2.3.1. Were cell numbers calculated?

Section 2.3.2. Does this also determine Fe3+ concentration?

Results

Title. Should this be labeled results and discussion? I do not see a discussion section.

Line 184. I am unsure what “There is basically without coagulation” means.

Figure 1. What does the horizontal dotted line indicate?

Line 220. How is current density an important parameter?

Section 3.3.2. Were these cells grown to levels of high concentration and already producing MC? Should this technology be used constantly or should it be deployed periodically? Is there a certainty and destruction/apoptosis of the cells is not leaking MC into the water?

Conclusions

What happens to other microbes/cyanos/algae in the environment? Would the non-targeted nature of this technology influence other parts of the aquatic ecosystem? Please discuss.

Comments on the Quality of English Language

Parts of the manuscript need editing for clarity.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The main question addressed by the research is how to efficiently remove Microcystis aeruginosa (M. aeruginosa), a cyanobacteria responsible for algal blooms, from water bodies experiencing eutrophication. The presence of M. aeruginosa poses significant challenges to water quality and drinking water safety due to the production of toxins and organic matter that can be harmful to humans, animals, and aquatic life. The research focuses on the development of an electrochemical algae removal technology, specifically combining electro-coagulation (EC) and electro-oxidation (EO) methods, to address the limitations associated with individual techniques.

Additionally, the study explores the mechanism of the combined EC-EO system, particularly emphasizing the use of the electro-Fenton process (EF) with iron electrodes and graphite felt cathodes to improve efficiency and minimize potential sludge generation.

In summary, the research addresses the need for an environmentally friendly and cost-effective method to combat the eutrophication problem caused by M. aeruginosa, focusing on a novel approach that combines electro-coagulation and electro-oxidation for efficient algae removal and AOM control.

The article is concise and fairly well-described; however, it has a fundamental flaw - the lack of discussion. I propose that the authors combine both the results and discussion sections and add the latter into specific subsections. If there is limited research on the subject, references or alternative methods can be described. In its current form, it is challenging to relate to the presented results. The idea itself is interesting and has developmental potential, so it is worthwhile for the authors to make efforts to thoroughly consider their results.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Looks good. Thank you for the edits and clarifications.

Reviewer 2 Report

Comments and Suggestions for Authors

I appreciate that the authors made corrections and added a fragment, but I think they still did not use the full potential of the results. In most of the text, the changes are cosmetic in nature. The manuscript is suitable for publication in this form, but it would be better if more work was done on it.