Embedding Circular Economy Principles into Urban Regeneration and Waste Management: Framework and Metrics

Round 1

Reviewer 1 Report

This is a potentially interesting paper that addresses an important urban regeneration problem. The presentation is up to merit. Results are okay. In this study There main scenarios are developed to assess resource impacts of different waste strategies. Findings suggest potential trade-offs between strategies centred around energy recovery from waste and strategies which prioritise recycling of recyclable fractions from. waste. Finally, some conclusions are drawn pointing to pathways to maximise optimal resource use and waste infrastructural provision in urban regeneration. However, before I can recommend this paper for publication, it should be revised subject to the following suggestions.

1. There are some typo mistakes for instant see “£7billion” use space between £7 billion.
2. All figure should be drawn again with good quality. Figures are blur. For instant see figure 3 and figure XX.

• Reference style should be according to the journal requirement.

1. There is some grammatical mistake, look at line 753, it should be years not year. Author is requested to please check the grammatical mistakes in the whole manuscript.
2. The author is requested to draw pie charts for all the tables.
3. Please check the sub-heading numbers in whole manuscript.

• Include some percentage data in the abstract and conclusion.

Author Response

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Reviewer 2 Report

The idea of the article is perfect, but the article has significant shortcomings. The article is very descriptive initially; it is written very broadly, not aptly on the topic. The description then prevails throughout the article. The article is also dominated by shortcomings in the numbering of tables, images, formatting, etc. This article looks like it was put together quickly. The article also contains many grammatical errors, typos. A significant reworking of the article is necessary. Just some recommendations for improvement:

line 19 the abbreviation CE must be explained when used first times - the abstract and the main part of the text,

line 82 what is OPDC? It is necessary to explain. The explanation is probably only in line 213,

in parts 2 and 3, miss the pictures to complete the better imagination of CE; The image can then also be used as a graphic abstract. Also, miss the graphs here. It was appropriate to add an overview of publications from databases: Scopus, WoS and CCC,

line 153 what is MFA??? – it is describe in line 163,

line 172 it looks as if the case study was not yours, and it is presented in a descriptive way,

line 178 wrong formatting, the paragraph should not be there,

line 221 what is C&D waste,

line 241 what is DMC,

line 247 what is GLA,

line 254 where were these publications published? Were they articles, magazines, studies? Is it traceable?,

line 291 what is AD,

line 297 – (Table 1-3) is missing,

line 302 what are BAU scenarios?,

line 326 Figure xx is in the text. It is bad describe of Figures,

line 327 – the Figure has no name; poor quality,

line 332 and 333 based on the title of sections 4 and 4.1, I dare say that the article is based only on their findings; your contribution to the article is missing,

In part 4, you just describe how someone did something, which is not your research. There is no explanation of the various abbreviations used,

line 460 the figure is unreadable has low quality. Some shortcuts need to be explained, and Figure 3 looks like it was taken from someone. Furthermore, where are Figures 1 and 2, when the first figure is on page 10 and is denoted as Figure 3. It is a general picture (in lines 455 and 456); it is described as only an illustrative picture. I would expect it to be a figure that completes your article, not just an illustration,

line 481 Table 1 should also be mentioned. There is no complete header in Table 1. Table 1 is not your research, as you list resources below it,

line 479 and line 497 have the same numbered - 4.3.2,

Based on which point 4.3.4 is processed, it is not clear because, e.g. gypsum, does not occur anywhere;

line 552 – 65% is listed there as a small one, number 1. I assume it was shown this way in some other article,

In the last paragraph in section 4.3, some statements cannot be verified; there is also an unknown abbreviation;

line 585 – you describe that something can be seen in figure 1. Figure 1 is missing!!!!!!

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The topic of the manuscript is highly relevant and extremely timely. There is a need for more circularity on urban level. However, the manuscript has key shortfalls that prevent it's publication. The comments exemplary demonstrate the weakness of the manuscript:

• The title announces circular economy principles. Traditionally, the principles cover the entire life cycle of material, but this paper focuses on material and energy recovery only.
• The paper claims a lack for exploring circularity in urban regeneration projects and aims to fill this gap by selecting and assessing energy and material flow related indicators. The methodology lacks of novelty, because several other authors in the industrial ecology domain developed indicator framework to assess urban metabolism and the authors neither reviewed these studies nor outlined the contribution of their work beyond the state-of-the art. The proposed methodology and selected indicators are not specific to regeneration projects and the key challenges for transforming an existing socioeconomic metabolism are missing. Next, quantification of the MFA system shows weaknesses. A lack of local data availability is compensated by rough estimates, such as the use of per capita DMC data. A justification for the appropriateness of the downscaling is not given. The validation of computed material flows is missing.
• The comparative analysis of the scenario results simply lacks of a methodology. The findings, whereas Scenario X is better than Y are just statements without referring to the results of an evaluation step. Such evaluation step would requires a comprehensive impact assessment. Among others, this shortcoming prevents evidence-based conclusions of the analysis.

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

Embedding Circular Economy principles into urban regeneration: A circular assessment framework and metrics

The authors should address the following comments/suggestions to improve the quality of the article:

• Line 32: The introduction should highlight the extent to which cities consume resources. For example, cities are projected to make up 68% of the global population by 2050. Cities cover less than 2% of the earth’s surface but consume 78% of the energy generated and produce 60% of greenhouse gas emissions. (https://www.un.org/en/climatechange/climate-solutions/cities-pollution). Also, urban land consumption outpaces population growth by about 50%: https://www.worldbank.org/en/topic/urbandevelopment/overview.    
• Line 42: please use the gender-neutral word “human” rather than “man-made” 
• The bulk of the introduction dwells on the background information (lines 4061). The introduction should focus more on the research gaps and the study’s contributions (lines 63-71). What are the limitations of similar previous studies that the paper is attempting to address? In other words, what sets this study apart from similar prior studies? 
• Figures: Please enlarge Figures 2, 3, & 5 to make them more legible.
• The discussion should highlight how the study findings support/corroborates, or differ from prior studies and likely explanations. However, not a single piece of literature was cited in the section. 
• The section is also expected to underscore how the paper adds value to the literature. 
• It should also discuss the key lessons of the paper and what the findings mean in terms of implications for urban planning policy and practice.
• Important works of literature on circular economy that are related to municipal waste are missing. They should be used to enrich the introduction and the discussion sections.

Author Response

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Author Response File: Author Response.docx

Reviewer 5 Report

The topic of the paper is of great importance, as it focuses on embedding circular economy (CE) principles into urban regeneration. The aim of the paper is to contribute to bridge the implementation gap at the urban level by providing an analytical framework and set of metrics to evaluate application of CE principles in urban regeneration projects related to planning circular destinations of waste, resorting to the case of Old Oak Common and Park Royal area (west London), a large urban regeneration project.

I feel that the discussion of results is not really a discussion, but a concluding section. The paper should include either a discussion section or a discussion and conclusions section where the discussion is further expanded. The authors state that the analysis provides insights into the implication of different combinations of technology choices for end-of-life treatment of waste in regeneration plans, which they do. I ask if they could elaborate on planning policy recommendations taking these insights into consideration. I strongly agree that socio-economic and environmental factors have a strong bearing on the assessment of suitability of different technology choices for waste recovery and this should be stressed from the start.

Figure 3 is hard to read because of low resolution.

There is a numbering repetition of subsections: 4.3.2 Household Waste and 4.3.2 Commercial and Industrial Waste.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Response to reviewer 3 comments are adequate.