Designing a Framework for Materials Flow by Integrating Circular Economy Principles with End-of-Life Management Strategies
Round 1
Reviewer 1 Report
The article “Designing closed loops for material flows combining circular economy methods with end-of-life strategies” presents a relevant area of research in the circular economy field. It has the potential to improve our understanding of how to adjust end-of-life practices to directly contribute to circular economy.
From an experimental point of view, the authors performed an interesting study on the treatment of agave. However, the framework was not synthesized in a coherent manner and does not provide much novelty in the field. I do not think this paper is suitable for publishing in Sustainability in its current form.
Here are the detailed comments and questions I would like to address to the authors. It would be helpful to include the line numbering in future submissions to easily point out the comments I have.
Language: The article consists of very long sentences (more than 5 lines) with little linking between them. Try to make the sentences shorter (one idea in one sentence). Besides, the grammar needs to be extensively reviewed.
Title: The title is a bit misguiding because it suggests combining circular economy with end-of-life strategies, which in my opinion are the same concept. Besides, it should inform that a case study was performed.
Introduction: Again, I would like to emphasize on the fact that end-of-life management strategies (e.g., the 3-Rs mentioned) are in fact circular economy strategies. Circular economy is an umbrella that covers different domains including end-of-life strategies. For example, remanufacturing and refurbishing are common circular economy strategies where in the introduction they are defined as end-of-life strategies only. Another misguiding sentence is that “there are very limit end-of-life management strategies to apply for keeping waste materials in recycle usage, as well as the closed loops of circular materials flow for industries to follows.” In the last decade, there have been hundreds of articles about those strategies and demonstrations of how they are applied to real life scenarios.
Method: It is not clear how your framework was designed with the five stages. Make sure to explain why you wanted these elements and why in this order.
Figure 1: You should introduce the figure after the first instance of mentioning it in the text. It is also repeated in Figure 4, so it is just redundant and should be removed.
Figure 3: You can add an arrow to the left of the image to show how it is bottom up because the natural way of reading it is from top to bottom.
Method: “Industrial ecology is a school of thought from EMF” is not accurate. The EMF was first launched in 2010 while the concept of industrial ecology originated in the late 80s.
Figure 5: You should introduce the figure after the first instance of mentioning it in the text.
Method: “monitor of waste via screening Life Cycle Analysis (LCA) method” is not clear in the framework. Monitoring is an action, so I do not understand why is there a possibility of a decision (“No”) in the framework? Indicate what is the questions you are assessing the screening LCA with to make the decision.
Method: “There are multiple types of business models and can be classified into 3 groups: design, use and recovery” is not clear. First, do you mean circular economy business models or business models in general? Besides, the 3 categories are not really business models. A business model of selling a product for example doesn’t fit any of them. Leasing a product as well. Can you explain more?
Method: Avoid using words like “prestigious scholars.”
Method: Add the source directly when you mention the “Fuzzy In- telligent Traffic Signal (FITS) tool can be applied.”
Preliminary application: “Scandinavian countries including Sweden, Denmark, Norway and Fin- land are always at the top of the world in leading the trend of sustainable development goals” While you added the source for New Zealand, you do not have a source for this!
Preliminary application: Section 3.1 and 3.2 only contain background information, and thus should be placed in the introduction or omitted.
Preliminary application: “the population is projected to reach to 9 billion by 2050” do you mean the world population? Speaking about a Mexican report it might be confusing.
Case analysis: I am wondering what is your threshold when you mention “after identified that there are enough agave bagasse wastes in Mexico”? In the framework, there was no identified threshold (e.g., % of total waste or tons of waste).
Case application: Some vague statements were used without evidence. For example, “the BCR (Benefit-Cost Ratio) could be considered greater than one” without real numbers to enforce it. Also, the screening LCA was mentioned without the proof it. Another vague statement is “the life cycle for this material can be used for a very long time” without quantifying it or supporting it with facts.
Discussion: The discussion section was more of a summary of what was done (more of a conclusion), with little discussion on the results and how they link to literature.
Author Response
Please find the authors responses summarised in the table format for ease. Many thanks!
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript entitled "Designing Closed Loops for Materials Flows Combining Circular Economy Methods with End-of-life Management Strategies" by Huang et al. presents a circular materials life extension model with end-of-life management strategies by following Deming’s circle Plan-Do-Check-Act and combining with Fuzzy Intelligent Traffic Signal (FITS) tool, Benefit-Cost Ratio (BCR) and Life Cycle Analysis (LCA). A business case study using agricultural wastes was analyzed to prove the applicability of model. The key steps in each phase were indicated and a new composite material arised using circular economy methods and end-of-life management strategies. The manuscript is well-structured with very helpful figures and proposes a very interesting model with practical application. For the above reasons, I propose its publication.
Author Response
Many thanks for your encouraging comments! Best regards!
Reviewer 3 Report
The study deals with the circular economy, which is one of the topics of interest in the literature. The connection between the topics covered in this context is strong. The layout of the study is well designed. The model established in the study is suitable for the purpose of the study. subject has been discussed in detail. In future studies, the study can be expanded by adding carbon neutral and green consensus dimensions to a sector/product/company sample with high carbon emissions.
Author Response
Many thanks for your comments, we will add carbon neutral and green consensus dimensions to a sector with high carbon emissions in our future work. Best regards.
Reviewer 4 Report
This work is very interesting and valuable in the field of the circular economy. End-of-life management has many merits to upscale the life cycle. Here are some points for your consideration:
(1) After reading all the material, I think this work is more like a review, not like one research article!!
(2) There are too many figures, totally 12. I think most of them can be merged together. Some can be deleted or moved to the supporting information file. For instance, the framework figures are too general. Figure 13 seems too simple.
(3) Many important and deep works have been published in this field. Please read them for your manuscript.
Potentials and Prerequisites on the Way to a Circular Economy: A Value Chain Perspective on Batteries and Buildings. Sustainability 14, 956 (2022).
Emerging anthropogenic circularity science: principles, practices, and challenges. iScience 24, 102237 (2021).
Megacities need both: Circular economy and final sinks! Waste Manage Res 39, 1437-1439 (2021).
Toward a circular economy: A system dynamic model of recycling framework for aseptic paper packaging waste in Indonesia. Journal of Cleaner Production 301, (2021).
Closed-loop sustainable product design for circular economy. Journal of Industrial Ecology 25, 1430-1446 (2021).
Mapping anthropogenic mineral generation in China and its implications for a circular economy. Nat Commun 11, 1544 (2020).
Author Response
Please find the authors responses summarised in table format for ease.
Many thanks!
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you for addressing my previous comments. I think that the current form of the manuscript is sufficient for publication in Sustainability.
