Which Is More Environmentally Friendly? A Comparative Analysis of the Environmental Benefits of Two Waste-to-Energy Technologies for Plastics Based on an LCA Model
Round 1
Reviewer 1 Report
- Manuscript has some typos, revise carefully, and correct it
- Line 49 changes “164%, 89% and 87%” to “164, 89, and 87%”. The same recommendation for all manuscript (lines 106, etc.)
- Figures 2.1 and 2.2 need to improve the quality at minimal 300 dpi, because in the present form have very poor resolution
- Table 3-1. Why is important to include 6 numbers after point? 6.071457, 0.758932, 11.851498, 1.481437
- Figures 3-2 and 3-3 need to include information in the exe Y, because the Figures only have “%”,
- Figures 3-4, 3-5, and 3-6 include the information for exe Y and improve the quality and minimal 300 dpi
- Manuscript has some interesting results but doesn´t have discussion, so improve discussion for all Figures and Tables
Author Response
Thank you so much for your high efficiency in reviewing our manuscript entitled “Which is more environmentally friendly?——A Comparative analysis of the environmental benefits of two waste-to-energy technologies for plastics based on an LCA model”. Those comments are all valuable and very helpful for revising and improving our article. We have studied carefully and the main corrections in the paper and the responds to your comments are as follows:
Point 1: Manuscript has some typos, revise carefully, and correct it.
Response 1: Thanks for your comment. The misspelled words and incorrect usage of punctuation in the manuscript had been corrected.
Point 2: Figures 2.1 and 2.2 need to improve the quality at minimal 300 dpi, because in the present form have very poor resolution. Figures 3-4, 3-5, and 3-6 include the information for exe Y and improve the quality and minimal 300 dpi. Figures 3-2 and 3-3 need to include information in the exe Y, because the Figures only have “%”.
Response 2: Thanks for your suggestion. All figures were updated to high-resolution versions to guarantee the quality at minimal 300 dpi. Information on the exe Y of Figures 3-2, 3-3, 3-4, 3-5, and 3-6 had been added.
Point 3: Line 49 changes “164%, 89% and 87%” to “164, 89, and 87%”. The same recommendation for all manuscript (lines 106, etc.) Table 3-1. Why is important to include 6 numbers after point? 6.071457, 0.758932, 11.851498, 1.481437
Response 3: Thanks for your comment. The correction of numerical expressions and table scales were completed. The correction could be clearly seen in lines 73 and 153. We took the issue of digits after the point seriously and consider that the issue needs to be consistent throughout the manuscript. After careful consideration had changed the six digits in the manuscript to three digits. The correction could be seen in Tables 3-1 3-2 and 3-3.
Point 4: Manuscript has some interesting results but doesn´t have discussion, so improve discussion for all Figures and Tables.
Response 4: Thanks for your professional thinking. Additional results analysis was added for the total environmental impact, phase impact, and process optimization sections. The relevant contents had been added to the text of section 3.1,3.2 and 3.3. The corrections mainly focused on the presentation of the results of the environmental impact accounting to become more comprehensive, and the analysis of the reasons for the results.
Reviewer 2 Report
Review (2023-05-06)
Includes the following typescript values of the publication:
Reviewer's assumptions:
1. In the comparative analysis, the environmental benefits of technologies for converting plastic waste into energy based on the LCA model, the operation of the technical system (system) has an impact on resources, techno- and ecosphere, including human potential. In addition, these interactions are taken into account when deciding on the choice of strategy.
2. Progress in individual areas of low-carbon, clean energy will be possible primarily through cutting-edge research and innovation to support development, including methods, strategies, tactics and mathematical models of LCA and the circular economy.
3. Different approaches to waste management, including emotional ones, can be distinguished for decision-makers, producers, consumers of polymer materials, classes depending on the rank of expected utility preference (RDEU).
Adequate knowledge:
The problem of pro-optimal criteria for conducting a comparative analysis of the environmental benefits of CCT and IAPGT technologies for converting plastic waste into energy based on the LCA model was specified and located. The analysis concerned important phases of the technological cycle: design and construction, investment, production, consumption in the current achievements of recycling engineering (40 bibliographic items), goals and tasks of cleaner processing of plastic waste.
Research skills and instruments:
Analytical and research skills: This document aims at skillful analytical-research knowledge of a subset of related issues of plastic waste and answers to the questions: which management technologies allow to achieve a high value of their recycling. The LCA strategy is an essential method of scientific conduct in order to analyze, evaluate and develop environmental benefits, supporting the optimization of technology for the production of a cleaner product. Mathematical models of processes and objects of utility research, technological diagrams, graphs and tables of results in large numbers (15), and other bibliographic data are cited competently and in the correct methodological order.
Purposefulness and creative attitude:
Creative, developmental solution of the task: The condition for optimization is a mathematical model - a multivariate model of utility, efficiency and problem solution are described. The model indicates the sensitivity of Ln to Kj, Kj is the value of the life cycle assessment index of j-this type of environmental impact, and Ln is the value of the nth inventory analysis data. The total environmental impact of the IAPGT is 111.59, many times higher than the CCT of 42.46, indicating that catalytic cracking technologies are more environmentally friendly at this stage.
Conclusion:
Taking into account the values of manuscript: the current context of plastics recycling engineering, especially intelligent (based on knowledge and innovation), sustainable (balancing generated and absorbed technological emissions) development and duration of cleaner production,
I assess the publication positively.
Author Response
Thank you so much for your high efficiency in reviewing our manuscript entitled “Which is more environmentally friendly?——A Comparative analysis of the environmental benefits of two waste-to-energy technologies for plastics based on an LCA model”. To enhance the professionalism of the expression of this study, we invited the MDPI editorial team to professionally touch up the manuscript in English. Thank you again for your recognition of our work.
Reviewer 3 Report
Dear Authors,
I have summarized few of my comments/suggestions below:
1. The title and abstract needs a better association. The title must be better reflected in abstract.
2. A good number of studies have already been done for different models already and optimization/best functional algorithms have already been sorted out, what is the novelty in comparative study, if you mean to bring the variables and their impacts pl highlight it in a better way. And do enrich it in Introduction section.
3. The diagrams/flow charts are mixed up, pl look if they can be made clearer.
4. The section Materials and methods may be described in sequence, there are irregular descriptions.
5. The abbreviations must be described initially.
6. The eq for sensitivity analysis ref 28 is in accordance with your model? Any assumptions, Is it enough to define the domain?
7. While talking about data management there is clutter of information, do summarize section-wise else the readers are not going to conclude anything out of it. Comparative methods must depict the ease of data assesment.
Needs minor checks.
Author Response
Thank you so much for your high efficiency in reviewing our manuscript entitled “Which is more environmentally friendly?——A Comparative analysis of the environmental benefits of two waste-to-energy technologies for plastics based on an LCA model”. Those comments are all valuable and very helpful for revising and improving our article. We have studied carefully and the main corrections in the paper and the responds to your comments are as follows:
Point 1: The title and abstract needs a better association. The title must be better reflected in abstract.
Response 1: Thanks for your professional thinking. We made the title clearer and more summarized, and the key words "comparative analysis", "environmental benefits" and "two technologies" mentioned in the title are clearly stated in the abstract.
Point 2: A good number of studies have already been done for different models already and optimization/best functional algorithms have already been sorted out, what is the novelty in comparative study, if you mean to bring the variables and their impacts pl highlight it in a better way. And do enrich it in Introduction section.
Response 2: Thanks for your suggestion. We were aware of the problems with the introduction and updated the current state of research in the field. More technical research status on waste-to-energy and research progress on the application of LCA model in sustainable areas had been added to the introduction. In addition, we added the innovative aspects of the study. Description of the innovation of this study had been added and we described more clearly the current status of the previous studies and the new things of this study, which could be seen in the last part of the introduction.
Point 3: The diagrams/flow charts are mixed up, pl look if they can be made clearer.
Response 3: Thanks for your suggestion. All figures were updated to high-resolution versions to guarantee the quality at minimal 300 dpi. Information on the exe Y of Figures 3-2, 3-3, 3-4, 3-5, and 3-6 has been added.
Point 4: The section Materials and methods may be described in sequence, there are irregular descriptions.
Response 4: Thanks for your professional thinking. The order of elaboration in the Materials and Methods section is very important, and we checked the model analysis flow and made sure that our description was carried out in accordance with the target boundary determination, inventory analysis, and study methodology presentation.
Point 5: The abbreviations must be described initially.
Response 5: Thanks for your suggestion. We have added to the opening section, in which the abbreviations are described. The correction could be seen in line 39.
Point 6: The eq for sensitivity analysis ref 28 is in accordance with your model? Any assumptions, Is it enough to define the domain?
Response 6: Thanks for pointing out our mistakes. We corrected the errors in the cited literature and used the correct citations. In addition, we carefully checked the feasibility of the sensitivity analysis again to ensure the accuracy of the results.
Point 7: While talking about data management there is clutter of information, do summarize section-wise else the readers are not going to conclude anything out of it. Comparative methods must depict the ease of data assessment.
Response 7: Thanks for your suggestion. A clear summary is important to the reader. We sorted out the data derived from the comparison, and added to the novelty and usability of the research methods of this study. The corrected discussion and conclusions could be seen in subsection 3.2 of the Discussion section and in the Conclusion section. The benefits of comparative methods were complemented in the Introduction section.
Point 8: English Language minor checking comments.
Response 8: Thanks for your comment. The misspelled words and incorrect usage of punctuation in the manuscript had been corrected. To enhance the professionalism of the expression of this study, we invited the MDPI editorial team to professionally touch up the manuscript in English.
Reviewer 4 Report
This study conducted a life-cycle assessment model for waste-to-energy technology for plastics, and used the midpoint method to analyze the environmental benefits of catalytic cracking technology and incineration and power generation technology. The results showed that catalytic cracking technology is more environmentally friendly. The sensitivity analysis showed the treatment units with high impact on the results, the process optimization section predicted the efficiency of technology optimization and advocates future technology development to explore in the direction of using clean energy, upgrading equipment and updating catalysts. The results of this study can provide ideas for the optimization of two kinds of waste plastics energy technology, and provide a practical path for the future development of high value treatment for waste plastics. This study is quite interesting and covers timely subject in the field. There are minor amendments which requires the authors to take action. Please find comments as below:
1. Introduction: Only 9 references have been discussed which is quite inappropriate to expose the existent research gap and importance of the work. Please elaborate on the most recent articles in the field given attention to critical analysis. 20-25 references could be sufficient.
2. Novelty of the work should be presented in more clear manner to elucidate the significant contribution through this study.
3. Quality of figures are extremely poor.
4. System parameters should be enriched with more specific details.
5. Results should be supported scientifically.
6. Comprehensive proofread is essential throughout the manuscript to rectify the typo/grammatical errors.
Comprehensive proofread is essential throughout the manuscript to rectify the typo/grammatical errors.
Author Response
Thank you so much for your high efficiency in reviewing our manuscript entitled “Which is more environmentally friendly?——A Comparative analysis of the environmental benefits of two waste-to-energy technologies for plastics based on an LCA model”. Those comments are all valuable and very helpful for revising and improving our article. We have studied carefully and the main corrections in the paper and the responds to your comments are as follows:
Point 1: Only 9 references have been discussed which is quite inappropriate to expose the existent research gap and importance of the work. Please elaborate on the most recent articles in the field given attention to critical analysis. 20-25 references could be sufficient.
Response 1: Thanks for your professional thinking. We were aware of the problems with the introduction and updated the current state of research in the field and added to the references. More technical research status on waste-to-energy and research progress on the application of LCA model in sustainable areas had been added to the introduction.
Point 2: Novelty of the work should be presented in more clear manner to elucidate the significant contribution through this study.
Response 2: Thanks for your suggestion. In the introduction we added the innovative aspects of the study. Description of the innovation of this study had been added and we described more clearly the current status of the previous studies and the new things of this study, which could be seen in the last part of the introduction.
Point 3: Quality of figures are extremely poor.
Response 3: Thanks for your suggestion. All figures were updated to high-resolution versions to guarantee the quality at minimal 300 dpi. Information on the exe Y of Figures 3-2, 3-3, 3-4, 3-5, and 3-6 has been added.
Point 4: System parameters should be enriched with more specific details.
Response 4: Thanks for your comment. The meticulous improvement of the system parameters is important. We added relevant information to the study limitations, which will be explored in depth in future studies. We used 18 of the environmental impact categories as indicators for the analysis. The parts not included in the analysis indicators were described in the study limitations section of the conclusion. In addition, we pointed out the direction of optimization for future studies.
Point 5: Results should be supported scientifically.
Response 5: Thanks for your professional thinking. In the results section we reviewed the existing studies and added scientific validation of the results. When analyzing the data for the cause of the results, we focused on the reasonableness of the results and made connections to existing research results, which could be seen in Chapter 3, LCA results analysis, sensitivity analysis and technical optimization.
Point 6: Comprehensive proofread is essential throughout the manuscript to rectify the typo/grammatical errors.
Response 6: Thanks for your comment. The misspelled words and incorrect usage of punctuation in the manuscript had been corrected. To enhance the professionalism of the expression of this study, we invited the MDPI editorial team to professionally touch up the manuscript in English.
Reviewer 5 Report
This paper is showing a good effort in the idea of recycling waste plastics, the author addressed a serious problem but the paper needs only minor revision.
1- The introduction part required to be updated by new recent studies and add a table showing significant parameters related to this work.
2- All given images required higher resolution, especially the last 3 figures.
3- The author must mention the limitations and future perspectives of this study.
There are some minor mistakes and typo errors required to be proofread.
Author Response
Thank you so much for your high efficiency in reviewing our manuscript entitled “Which is more environmentally friendly?——A Comparative analysis of the environmental benefits of two waste-to-energy technologies for plastics based on an LCA model”. Those comments are all valuable and very helpful for revising and improving our article. We have studied carefully and the main corrections in the paper and the responds to your comments are as follows:
Point 1: The introduction part required to be updated by new recent studies and add a table showing significant parameters related to this work.
Response 1: Thanks for your professional thinking. We were aware of the problems with the introduction and updated the current state of research in the field. More technical research status on waste-to-energy and research progress on the application of LCA model in sustainable areas had been added to the introduction. The table of environmental impact indicators related to this work can be found in Table 2-3.
Point 2: All given images required higher resolution, especially the last 3 figures.
Response 2: Thanks for your suggestion. All figures were updated to high-resolution versions to guarantee the quality at minimal 300 dpi. Information on the exe Y of Figures 3-2, 3-3, 3-4, 3-5, and 3-6 has been added.
Point 3: The author must mention the limitations and future perspectives of this study.
Response 3: Thanks for your comment. We added the limitations of this study in terms of data and parameters and the prospects of industrial integration of this study in the discussion and conclusion section.
Point 4: There are some minor mistakes and typo errors required to be proofread.
Response 4: Thanks for your comment. The misspelled words and incorrect usage of punctuation in the manuscript had been corrected. To enhance the professionalism of the expression of this study, we invited the MDPI editorial team to professionally touch up the manuscript in English.
