Resource Disposal and Products of Fly Ash from Domestic Waste Incineration in Zhejiang Province, China: Migration and Change of Hazardous Heavy Metals

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Authors should review the guidelines and format for authors.

Table 1, the authors should explain their experimental working conditions.

In the first paragraph of the introduction, the authors must explain in an integrated way the implications of the incineration of domestic waste. In addition to the generation of ash, the generation of gaseous pollutants and the possible use of energy.

The authors must explain how their work objective is positioned considering all waste management sustainability strategies.

This reference may help authors.

 

https://0-doi-org.brum.beds.ac.uk/10.1016/j.enconman.2022.115905

In section 4. Implications of sustainability, authors must use parameters or indicators of sustainability to give quantitative arguments.

The authors can project based on their study, parameters or economic evaluation of their proposal.

Considering the challenges that other countries may represent to implement their strategy.

Authors must present a conclusion section

   

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The research team evaluated the low-temperature pyrolysis of fly ash and other related treatments for minimizing the environmental impact of fly ash obtained from domestic waste incineration. Here are some issues the authors needs to address:

1) English is extremely difficult to understand across the manuscript

2) The whole purpose to design the fly ash treatments in this work (in Figure 1) is to detoxify the fly ash. The authors stressed the shortcomings of the conventional cement curing technology for fly ash disposal, which is the leaching possibility of heavy metals. I expected the authors' design can lower the heavy metals content significantly in the treated fly ashes. But based on their results, this method is not effective. Instead, Cd, Zn, Ba increased significantly after their treatment. For Pb, about 50% removal was observed but still the Pb content in the treated fly ash is very high. For the reduction of dioxin, the team chose Cl content in the fly ashes as the reference. It is better to show dioxin content in fly ashes rather than Cl content. Put aside the reasonability of this reference, the removal of Cl is not so effective as there are still 50% of it there (see Fig. 2A).

3) The authors mentioned cement kiln co-disposal is one part of their treatment method. But it is not shown in the flowchart in Fig. 1. It will be better to add it to the figure. 

4) the authors need to provide leaching test data (e.g., TCLP) to show the advantages of their treatment method. 

Comments on the Quality of English Language

 English is extremely difficult to understand across the manuscript

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Please find my comments in the attached file.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The English should be improved. Moderate English editing is required. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The paper focuses on the analyses of the migration and transformation laws of heavy metal pollutants in the process of resource utilization of fly ash of domestic garbage incineration, as well as the prediction of the needs of the industry demands on resource utilization and technological performance. The authors used the method of validation and evaluation of the system of resource utilization technology of fly ash, using low-temperature pyrolysis of fly ash, water washing, co-disposal in cement kiln, regeneration of salt ionic membrane alkali production as the path of resource utilization technology of Zhejiang Province and analysing the migration and transformation laws of heavy metal pollutants in the area from the domestic garbage incineration process.

The paper topic is of current interest however the research still missing crucial information on the validity and correctives of the results obtained. The methodology used failed to provide information on the reference standard used as well as the method used based on the accredited or national accepted standard guidelines.

In addition the English language should be corrected by professional proof-reader. In some lines it was difficult to understand the aim of the authors.

For example the following paragraph should be corrected and reformulated to be more understandable for the readers ’’  In this study, the low-temperature pyrolysis of fly ash + washing + cement kiln co-disposal + regeneration salt ion membrane alkali production as a resource utilization technology path, to explore the migration and transformation law of heavy metal pollutants in the process of domestic waste incineration fly ash resource utilization, first of all, 24 kinds of metals and 3 kinds of non-metals and 8 kinds of oxides in the fly ash (FA), pyrolysis ash (PA), and water-washing ash (WA) in the process of domestic waste incineration to carry out a comparative analysis.’’

 

What do the authors means with ‘’24 kinds of metals’’? They can formulate that they analyse 24 metals…and delete the word kinds.

 

In the line 19, the authors mentioned that ‘’we paid attention to the changes of heavy metal contents and acidity and alkalinity of the types of ash in the regenerated salt (RS) and incineration processes’’. What do they mean with ‘’we paid attention’’?

 In the paragraph, line 61 the authors should present the source.

 

The authors were mostly based on the concentration of the elements found. What about the environmental risk? Without the environmental risk the economic feasibility will have no sense for further analysis.

The authors were presenting their work as contribution for rational planning of the industrial layout for washed fly ash, development of fly ash washing industry standards and development of management standards for utilizing by-products of waste salt, stipulating regulations and quality testing requirements for legal sales of by-products. However, the results obtained and presented are with weak background on providing enough scientific proofs for planning and development of industrial standards for obtaining of by-products from fly ash washing industry.

Comments on the Quality of English Language

English must be improved by professional proofreader. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 5 Report

Comments and Suggestions for Authors

Dear authors,

thank you for you work.

I think it would be better to make results (short) and after Discussion with details.

Also for your topic a lot of high quality work. You can make introduction  more informative and use more references.

If you'll make more analysis for Fig 2, Fig3, Fig4 and Fig5 you'll have no locuses (pp 5-8) and it would be informative and better.

 

Best regards,

reviewer

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed the reviewers' comments and have improved their manuscript.

Author Response

Thank you very much for your comments and approval.

Reviewer 2 Report

Comments and Suggestions for Authors

Overall, the manuscript is greatly improved. But for my 2nd and 4th comments, I hope the research team can take it more seriously. I made the comments on high heavy metal residual within the treated fly ashes, not the RS or salt products in Fig 4. The most important part is to show the treated fly ashes or these abundant solid waste is safe to reuse with controllable health risk. The Design was bad as the team skipped this most important evaluation of the treated fly ashes and in your answer to my 4th comment, I am quite surprised that you have dispose off your fly ash samples. But I am happy to see the team add some statement in Line 220-223, page 6. That's very important as the policymakers may use our research conclusion to make policies that may affect everyone's health. If possible, please add the concern on treated fly ashes in the abstract to remind others to do the metal and dioxin leaching tests. 

Author Response

We appreciate the reviewers' guidance and suggestions. We have taken their comments into account and made changes to the abstract section, specifically regarding the determination of heavy metals and dioxin leaching from ash. These changes are detailed in lines 27-28 of the manuscript. Thank you for your helpful suggestions. We will continue to work on improving this study in the future.

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for responding to all my comments and questions. 

Comments on the Quality of English Language

The English of the manuscript has improved. There are only small editing mistakes. 

Author Response

Thank you for your suggestions. I carefully reviewed the grammar and made necessary changes to the manuscript. I appreciate the reviewer's approval and helpful suggestions.