Practical Improvement Scenarios for an Innovative Waste-Collection Recycling Program Operating with Mobile Green Points (MGPs)

Round 1

Reviewer 1 Report (Previous Reviewer 1)

The authors present two improvement scenarios of a waste recycling collection service.

Major:

1.     In a scientific publication, the results are usually exactly quantified. A table like 4 and 5, which only depict statements without any quantification are generally less common. 

a.     For example, which experiment did you conduct to quantify by how much the MGPs' drivers strain decreased and their health improved? 

b.     Please specify which pollutants have been reduced by exactly how much instead of simply stating “Air pollution diminution in Attica Region” 

c.      “Great CO2 emissions decrease” CO2 is an air pollutant, why is this not included in the statement “Air pollution diminution in Attica Region” ?

d.     By how much did the “MGPs maintenance costs decrease”?

e.     You state that there is a “Great fuel cost decrease” and an “Increased energy conservation”. What type of energy apart from fuel is used in this system? Please exactly quantify the reductions.

f.      Please exactly quantify the “Mitigation of climate change negative impacts” 

2.     Please specify the experiment you used to proof your following statement: This reality reveals the reduction of the MGPs’ drivers strain and the improvements of their physical and mental health long term, however it reveals at the same time the growth of their strain and the deterioration of their physical and mental health short term.

3.     I can’t see any justification or methodology in your paper that assesses the mental health of the drivers. How do you know that mental health improved long term but reduced short term. 

Minor:

4.     Why do you double the distances? I thought that the vans complete a tour with multiple stops. When they return home, they could just drive back from the last stop directly instead of going past all stops again in reversed order.

5.     Please add to table 1 and table 2 whether these are round trip distances.

6.     Table 4, what is the difference between kilometre distance reduction and time distance reduction? Is there simply a comma missing between time and distance? If not, what is a “time distance”? What do you mean by “MGPs operational lifecycle increase”. Do you mean that the operational lifecycle is longer, meaning that the vehicle can be used for a longer time/distance. If yes, why? It is still the same vehicle, isn’t it? Or do you mean that because of the kilometre reduction, the vehicle can stay in service for longer?

7.     Table 4 vs table 5. What is the difference between “Kilometer distance reduction” and “Great kilometer distance reduction (monthly and annually)”. If there is a reduction in the annually driven km, then there must also be a reduction in km driven in some months of the year. Please be specific by stating, for example, that the tours have been merged and because of this the tour distances increased but the total distance travelled across the system is reduced. 

Author Response

Practical Improvement Scenarios for an Innovative Waste Collection Recycling Program Operating with Mobile Green Points (MGPs)

ID: Inventions-2434511 - revised

Reviewer 1

Major:

1. In a scientific publication, the results are usually exactly quantified. A table like 4 and 5, which only depict statements without any quantification are generally less common. 

Answer to statement 1

A precise quantification of our results are presented in Table 3, while the Tables 1 and 2, Figure 10, as well as the subsections 4.1 and 4.2, are fully developing our proposed scenarios (in measurable manner). The information of Tables 4 and 5 are supplementary to our study since offer a more critical and pluralistic evaluation-validation-verification of the conducted analysis and findings.

1. For example, which experiment did you conduct to quantify by how much the MGPs' drivers strain decreased and their health improved? 

Answer to review comment a

The quantification and the extend of how much MGPs' drivers strain decreased and their health improved necessitate the conduct of in-person interviews with the drivers, something that it is out of scope of our study. However, taking into consideration that a more precise information should be useful to our study we (the authors) made a relevant literature search and selected citations were retrieved on the drivers strain issue, thus, the following paragraph was added:

Stress is the primary cause of strain and health problems for occupational drivers whose jobs directly relate to public safety. Although several stress theories and scales have been proposed, the exact method of adequately measuring the stress of occupational drivers remains unclear (Chung and Wu, 2013). The drivers’ strain on our study is a subjective feeling that is primary determined by the drivers’ professional experience in driving with full cargo, the driving safety in alignment with the number of routes driven and their whole time of driving on the go. In the relevant literature research has focused on the reliability and validity to associate strain and health problems with occupational drivers.  Indicative parameters were that of burnout levels, cardiovascular disease symptoms, and self-rated health. Besides, physical demands, overtime, and stress-induced sleep problems were the primary stressors in occupational drivers (Chung and Wu, 2013). It was shown that an imbalance between effort and reward and overcommitment levels were strong and independent predictors of strain and health outcomes. Future studies should be also directed to develop a reliable tool to identify and to measure the stress of similar to MGPs’ professionals, as those working as public transport drivers under strain conditions and the healthy personality levels of, suspected, unhealthy drivers (Chung and Wu, 2013).

In the relevant literature it was highlighted a considerable divergence in organization and management practices that are associated with the performance of mental health providers, thus, it is an imperative need to compare and contrast the core organizational processes across high and low performing mental health providers national health service centers. To this end a research design can incorporate a full sample of low and high performing mental health providers, suggesting that the organizational approaches used to govern and manage mental health providers are associated with their performance. The research outcomes enabled a better understanding of what areas might need attention, including the development of appropriate governance frameworks and organizational cultures, in order to ensure that staff across the organization (in our study the MGPs waste collection management) feel “psychologically safe” and able to speak up when they see things that are going wrong. Besides, focus should be directed on enhancing quality of services rather than prioritizing cost-reduction; investing in new technology and digital applications; and nurturing positive inter-organizational relationships across the local health economy (Mannion et al., 2023). Last but not least, at evaluating the inadequacies faced by the public in accessing mental health services and the directions to improve in the future it is crucial to provide socially inclusive services to drivers enabling them to live a life free from mental health-related stigma or discrimination (Kulshrestha and Shahid, 2022).

1. Please specify which pollutants have been reduced by exactly how much instead of simply stating “Air pollution diminution in Attica Region” 

1. “Great CO2 emissions decrease” CO2 is an air pollutant, why is this not included in the statement “Air pollution diminution in Attica Region” ?

Answer to review comment b and c

The identification and the quantification of the exact pollutants generated from the MGPs' trucks/routes is out of scope of our study, since the air pollution is the aggregated phenomenon of all types of vehicles driven in such a large and densely populated city as Attica is. However, taking into consideration that a more precise information should be useful to our study we (the authors) made a relevant literature search and selected citations were retrieved on the air pollution situation in the area studied, the Attica region, thus, the following paragraph was added:

The Attica Region is regarded as one of the most arid urban regions in Europe. In this context it is noteworthy that its climate regime is influenced by the intense urbanism of the four recent decades, showing moderate warming, wind speed and direction changes and multiple extreme events. Besides, the multi-component industrial rise since 1960 is characterized by a declining trend to date; however it has determined drastic changes in the use of land, which has led to both environmental degradation and the impact on the local climate regime, expanding in the adjacent suburban areas. Moreover, the industrial activity is expressed by high contents of metals, and oil products (Makri et al., 2022). In the relevant literature there studies focused on the pollution record of selected points, sampling stations, of Attica indicating the temporal evolution of legislated polluting compounds, thus, supporting researchers to provide solutions and policy makers to focus on the whole Attica Region of potential policy alternatives (Makri et al., 2022).

In a recently published study on the western Attica Region and the neighbourhood Thriasio industrial zone it was argued that sulphur dioxide (SO₂) concentrations gradually decreased over the years thanks to fuel improvement, whereas nitrogen dioxide (NO₂) concentrations remained almost the same, or perhaps, a small decreasing trend during the last few years. Yet, the levels recorded at the nearby industrial zone of Attica were less than those observed in the Athens center: the sea breeze is, potentially, either beneficial as effective ventilation, or detrimental through the transportation of the polluting elements. Moreover, elemental concentrations of Ca2+, Mg2+, K+, Na+, NH4+, Cl−, NO3− and SO42− were determined in airborne particulates and were attributed to the industrial activity. Specifically, ammonium is likely to originate from the oil refineries and is enriched in the fine particles, chloride is due to a coastal effect and nitrate concentration is due to vehicle emissions. In the Attica urban/center area the enrichment of secondary aerosols, ammonium, and sulphates, in the fine particle fraction can reflect high traffic densities and domestic heating from the highly populated cities. Similarly, only Al, Ba and Zn were abundant while Cr, V, Mn, Pb, Cu, Ni, Ga and Rb were detected in traces. For PM₁₀, Al, Fe, Zn and Ba demonstrated the maximum concentrations during winter. Authors also concluded that the industrial area was the main polluting source, specifically for Cd, whereas Pb was originated from combustion processes up to municipal solid waste incineration, confirming our proposal of wastes selection in the source, as an imperative necessity. Ultimately, the air pollution can strongly impact on residents’ health, as the assessment of the excess lifetime cancer risk revealed that two people out of 30,000 are at risk (Makri et al., 2022).

Regarding the photochemical air pollution an early study (published 2 decades ago) identified that the levels of photochemical air pollutants: O₃, NO and NO₂, could be monitored in Athens and in the neighbouring (north-east to Athens center) region of the Mesogia plain (Spata, Artemis and Markopoulo) (Saitanis et al., 2003). It was detected that phytodetection of ozone was conducted using bioindicator plants and tobacco varieties revealing that the average maximum daily O₃ concentration was 60-75 ppb, while the 24 hour average ranged from 40-65 ppb. It is also noteworthy that both ozone bioindicator plants and tobacco varieties were highly injured in all regions confirming the phytotoxicity of those ozone levels. The levels of recorded NO and NO₂ at the three experimental stations of the Mesogia plain were considerably lower than those occurring in Athens center, enabling the disclosure of important background information concerning pollution levels in the Attica Region and its suburban areas, mainly those areas of Mesogia plain that accommodated the new international airport “Eleftherios Venizelos” in this region since March 2001 (Saitanis et al., 2003).

1. By how much did the “MGPs maintenance costs decrease”?

Answer to review comment d

The inverse relevancy between the “MGPs maintenance costs decrease” and the “number of routes”/ “distance of route” is also anticipated, since as fewer and shorter routes are made by the collection trucks, then, there is lower operation and maintenance costs of the whole truck fleet. However, taking into consideration that a more precise information should be useful to our study we (the authors) made a relevant literature search and selected citations were retrieved on the drivers strain issue, thus, the following paragraph was added:

The inverse relevancy between the “MGPs maintenance costs decrease” and the “number of routes”/ “distance of route” is also anticipated, since as fewer and shorter routes are made by the collection trucks, then, there is lower operation and maintenance costs of the whole truck fleet. Our research proposal to the future of waste collection method is highly linked to the transition to electric vehicle (EV) (truck in our study), having positively impacting on the climate, the environment, and the society in a substantially sustainable manner (Vega-Perkins et al., 2023). Indeed, in environmental terms the comparison of EVs to vehicles/trucks with internal combustion engines regarding the greenhouse gas emissions (GHGs) showed that for 60% of households in US there are moderate to high savings (i.e. 2.3 metric tons of CO2e reduction per household annually; 0.6% of energy burden reduction).  In economics and energy terms the fuel costs, and transportation energy burden (i.e. percentage of income spent on vehicle fuels), excluding in the analysis the purchase cost of the vehicles themselves, it was reported that over 90% of vehicle-owning US households would gain reductions in both GHGs and transportation energy burden by adopting an EV (Vega-Perkins et al., 2023).

These reductions are especially pronounced when combine them with cleaner electricity grids, lower electricity prices (relative to gas prices), and smaller drive-cycle and temperature-related impacts on fuel efficiency. Moreover, adopting an EV would more than double the percentage of households that enjoy a low transportation energy burden (2% of income spent on fuel annually). This equates to 80% of all vehicle-owning U.S. households. Nevertheless, over half of the lowest income households would still have a high EV energy burden (4% income spent on fuel annually  and due to no access to at-home charging this rises to over 75%). At a wider environmental and energy planning, while addressing the aforesaid inequity the following interventions are recommended: a) targeted policies to promote energy justice in lower-income communities, including subsidizing charging infrastructure; b) strategies to reduce electricity costs; and c) expanding access to low-carbon transport infrastructure (e.g. public transit, biking, and car sharing) (Vega-Perkins et al., 2023).

1. You state that there is a “Great fuel cost decrease” and an “Increased energy conservation”. What type of energy apart from fuel is used in this system? Please exactly quantify the reductions.

Answer to review comment e

Please refer to our answer of issue d in which the couple of (cost, energy) has been clarified.

1. Please exactly quantify the “Mitigation of climate change negative impacts” \

Answer to review comment f

For the scopes of our study “the negative impacts climate change” are related to policy and priority actions of mitigation in national and international levels. However, the quantification of negative impacts is out of our scope, but it is recommended as part of the contemporary national and international policies that cope with climate change mitigation regarding the Climate Change Conferences (COP) under the United Nations Framework Convention on Climate Change (UNFCCC) agreements. But please let us kindly note that such a quantification of climate change based only on our proposal of the trucks involved in our study (to be remote and isolated from other concurring and emitting sources of air pollution) is not feasible and realistic. 

2. Please specify the experiment you used to proof your following statement: This reality reveals the reduction of the MGPs’ drivers strain and the improvements of their physical and mental health long term, however it reveals at the same time the growth of their strain and the deterioration of their physical and mental health short term. ? 

3. I can’t see any justification or methodology in your paper that assesses the mental health of the drivers. How do you know that mental health improved long term but reduced short term. 

Answer to review comments 2 and 3

Please refer to our answer of issue a. The critical point here is that “at evaluating the inadequacies faced by the public in accessing mental health services and the directions to improve in the future it is crucial to provide socially inclusive services to drivers enabling them to live a life free from mental health-related stigma or discrimination”. A whole new and separated subsection 5.4 has been added, in which the mental health issue of strained drivers has been approached in a more detailed and comprehensive manner.

Minor:

4. Why do you double the distances? I thought that the vans complete a tour with multiple stops. When they return home, they could just drive back from the last stop directly instead of going past all stops again in reversed order.

Answer to review comment 4

The detailed design of our proposal has been specifically given at the already citations of: Tsimnadis  et al., 2022; Tsimnadis et al., 2023

5. Please add to table 1 and table 2 whether these are round trip distances.

Answer to review comment 5

The trip types of Table 1 have been visually differentiated by adding the pale grey for the one way trip and the bold grey for the round trip.

At the left-side bottom of Table 2 the asterisk of: “*Round Trip Distances” has been placed in the relevant Table 2-entries.

6. Table 4, what is the difference between kilometre distance reduction and time distance reduction? Is there simply a comma missing between time and distance? If not, what is a “time distance”? What do you mean by “MGPs operational lifecycle increase”.

Do you mean that the operational lifecycle is longer, meaning that the vehicle can be used for a longer time/distance. If yes, why? It is still the same vehicle, isn’t it? Or do you mean that because of the kilometre reduction, the vehicle can stay in service for longer?

Answer to review comment 6

The “time route reduction” has been typed in Table 4.

The “MGPs operational lifecycle increase” is a “time-chronological” term that refers to the operation time of the MGPs proposal.

1. Table 4 vs table 5. What is the difference between “Kilometer distance reduction” and “Great kilometer distance reduction (monthly and annually)”. If there is a reduction in the annually driven km, then there must also be a reduction in km driven in some months of the year. Please be specific by stating, for example, that the tours have been merged and because of this the tour distances increased but the total distance travelled across the system is reduced

Answer to review comment 7

At the bottom of Table 5 the following notation was added:

*Great kilometer distance reduction is also consistent with the outcomes of Table 3, referring to the fact that tours have been merged and because of this the tour distances increased but the total distance travelled across the system is reduced.

Author Response File: Author Response.docx

Reviewer 2 Report (Previous Reviewer 4)

This study presents and compares two practical improvement scenarios for the green city recycling program in region of Attica. This paper is very practical, but a practical paper can be valuable in fields where the application and implementation of its findings have direct implications for industry, organizations, or society. However, the authors need to improve the clarity and readability of the manuscript before its acceptance for publishing in the journal. In particular, the following issues need to be addressed.

Considering to name the two “improvement scenario” based on their characteristics. This will improve the clarity and readability.

Clarify the reasons of choosing the two scenarios. Are these two scenarios the only options for improving the current program? Instead of directly calculating the distance, time, fuel cost of the two alternatives, the authors could consider to use optimization modeling and GIS to obtain an optimal route of recycling.    

Author Response

Practical Improvement Scenarios for an Innovative Waste Collection Recycling Program Operating with Mobile Green Points (MGPs)

ID: Inventions-2434511 - revised

with main depot decentralization

with main depot decentralization and the merge of neighbouring remote routes

Reviewer 2

This study presents and compares two practical improvement scenarios for the green city recycling program in region of Attica. This paper is very practical, but a practical paper can be valuable in fields where the application and implementation of its findings have direct implications for industry, organizations, or society. However, the authors need to improve the clarity and readability of the manuscript before its acceptance for publishing in the journal. In particular, the following issues need to be addressed.

Considering to name the two “improvement scenario” based on their characteristics. This will improve the clarity and readability.

Answer to review comment

In the revised manuscript the “first improvement scenario” has been defined as “first improvement scenario with main depot decentralization”. Besides, the “second improvement scenario” has been defined as “second improvement scenario with main depot decentralization and the merge of neighbouring remote routes”.

Clarify the reasons of choosing the two scenarios. Are these two scenarios the only options for improving the current program? Instead of directly calculating the distance, time, fuel cost of the two alternatives, the authors could consider to use optimization modeling and GIS to obtain an optimal route of recycling.  

Answer to review comment

The selection of the two scenarios has been designed and implemented in the light of the environmental and the economics impact of them, comparing to the basic case that has been already developed in the citations of Tsimnadis et al., 2022; Tsimnadis et al., 2023. We, the authors, worked on the collected data and we utilized them in an integrated and in-depth analysis that was best fitting to scopes of our study. At a future time the optimization modeling and the GIS should also offer us a more pluralistic approach of our analysis but, at the time being, we synergistically utilized all data available.

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

The paper has some good contributions in terms of novelty and contribution. I have the following comments as follows:

1.       The abstract must indicate the significant findings in the last part of it. It should be more scientifically explained, not any informal or casual writing.

2.       The observations are so simple and insignificant. Derive the crucial observations, findings, and insights.

3.       What are the physical significances of MGP and THE GREEN CITY?

4.       The introduction should be based on the exact research gap, and the literature review should be based on the specific keywords-based review; finally, make an author's contribution table to show the novelty and effectiveness of the study. Show all referenced papers in the table to show the contribution of this study. Study these papers “Supply chain management of e-waste for end-of-life electronic products with reverse logistics” and compare the contributions within the literature to show the novel contribution of the study by the authors.

5.       Keywords should be perfect. The abstract should contain the details of the study and the findings in a very constructive way. A professional proofreading service is highly recommendable for English corrections.

6.       Please write the significant findings in the conclusions. Do not mention all assumptions which have been indicated within the model.

7.       Conclusions should be updated with more findings, limitations, and future extensions.

8.       There are several significant findings in the literature in this direction. Therefore, it is important to obtain the novel findings of this research. There must be a comparative study with the following articles in literature (Effect of circular economy for waste nullification under a sustainable supply chain management; Sustainable biodiesel supply chain model based on waste animal fat with subsidy and advertisement) to show the major contributions and findings.

9.       The applicability of the model should be explained. A real case study is required to prove the applicability of the study.

Good

Author Response

Practical Improvement Scenarios for an Innovative Waste Collection Recycling Program Operating with Mobile Green Points (MGPs)

ID: Inventions-2434511 - revised

with main depot decentralization

with main depot decentralization and the merge of neighbouring remote routes

Reviewer 3

1. The abstract must indicate the significant findings in the last part of it. It should be more scientifically explained, not any informal or casual writing.

2. The observations are so simple and insignificant. Derive the crucial observations, findings, and insights.

Answer to review comments 1 and 2

The Abstract section has been slightly revised in order the terms of “first scenario” and “second scenario” to be better conveyed in it. Besides, the “Discussion” part of our analysis has been enriched but a new subsection 5.4 in which the critical points of our proposals’ evaluation have been better conveyed and communicated with the readers of our study.

3. What are the physical significances of MGP and THE GREEN CITY?

Answer to review comment 3

The physical significance of the MGP and THE GREEN CITY has been attributed in alignment with the design and the implementation of MSW collection at the basic case that has been already developed in the citations of Tsimnadis et al., 2022; Tsimnadis et al., 2023. Then, the development of the two scenarios of this study enabled us, the authors, to utilize all available data in an integrated and in-depth analysis that was best fitting to scopes of our study. The scope is to provide a critical and creative approach of our analysis, while synergistically utilizing all data available and accumulated experience on this program.

4. The introduction should be based on the exact research gap, and the literature review should be based on the specific keywords-based review; finally, make an author's contribution table to show the novelty and effectiveness of the study. Show all referenced papers in the table to show the contribution of this study. Study these papers “Supply chain management of e-waste for end-of-life electronic products with reverse logistics” and compare the contributions within the literature to show the novel contribution of the study by the authors.

Answer to review comment 4

The proposed study has been included in the newly developed subsection 5.4

5. i) Keywords should be perfect.

Answer to review comment 5i)

The new keywords are:  “THE GREEN CITY” Recycling Program; First improvement scenario with main depot decentralization; Second improvement scenario with main depot decentralization and the merge of neighbouring remote routes; Distances; Fuel cost; Carbon dioxide emissions, Waste management

1. ii) The abstract should contain the details of the study and the findings in a very constructive way. A professional proofreading service is highly recommendable for English corrections

Answer to review comment 5 ii)

We made any possible effort to represent our study in a succinct and detailed manner, having also into consideration the word count restrictions and limitations that have to follow. The main analysis and findings have been substantially improved, considering the reviewers’ comments and improving our manuscript accordingly.

6. Please write the significant findings in the conclusions. Do not mention all assumptions which have been indicated within the model.

Answer to review comment 6

We made any possible effort to represent our study in a succinct and detailed manner. The main analysis and findings have been substantially improved, considering the reviewers’ comments and improving our manuscript accordingly.

7. Conclusions should be updated with more findings, limitations, and future extensions.

Answer to review comment 7

We made any possible effort to represent our study in a succinct and detailed manner. The main analysis and findings have been substantially improved, considering the reviewers’ comments and improving our manuscript accordingly.

8. There are several significant findings in the literature in this direction. Therefore, it is important to obtain the novel findings of this research. There must be a comparative study with the following articles in literature (Effect of circular economy for waste nullification under a sustainable supply chain management; Sustainable biodiesel supply chain model based on waste animal fat with subsidy and advertisement)to show the major contributions and findings.

Answer to review comment 8

The proposed studies have been included in the newly developed subsection 5.4

9. The applicability of the model should be explained. A real case study is required to prove the applicability of the study.

Answer to review comment 9

The proposal of this study is not a “theoretical paperwork” but a personally experienced  program, thus, it is actually a real case that offers a guide of improving the existing running program, showing also the key anthropocentric, environmental and economics aspects of improvement.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report (Previous Reviewer 1)

All my comments have been addressed.

Reviewer 2 Report (Previous Reviewer 4)

The authors have addressed my issues. 

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The authors present an interesting evaluation of a waste collection service as well as discussing two possible improvement strategies.

Major: 

1.     How do people get to the waste collection point? If they drive a car, this would  significantly add to the total emissions. 

2.     What is the average or maximum distance customers travel to the waste collection points?

Minor: 

3.     Outside Europe, it may not be common knowledge where the Attica Region is. Please add the specific country (Greece) to the Abstract etc.

4.     Line 225: I assume that the CO2 emissions you state is specifically for the distance travelled in your study and not an average value taken from the two sources you cite. Please re-phrase this to make it clear.

5.     4 times the weekly distance driven is not strictly equal to one calendar month of driving.

Reviewer 2 Report

Detailed work done by the authors

Reviewer 3 Report

This review comments on a study that proposes two practical improvement scenarios for the recycling program of THE GREEN 20 CITY. While the study presents interesting ideas, there are several issues with the methodology description and inconsistencies between the abstract and the document.

Specific issues identified in the study include the following:

• Section 1.1 could be summarized and the subsection eliminated.
• The introduction does not clearly show the novelty of the proposal nor provide a comprehensive review of related works.
• The data in lines 196 to 207 does not consider changes in traveling time during working hours, nor does it contrast with real truck travel times.
• The scenarios used for assessment are not clearly defined.
• The theoretical basis for the methodology used for creating circles is not explained.
• Section 3.1.1 does not provide sufficient detail on how routes are designed and optimized.
• The calculations, such as LTNE in line 673, could be summarized in the text and presented in full in the appendix.
• It is unclear how the advantages and disadvantages of the proposed scenarios were established or combined since they represent different aspects.
• The conclusion in the abstract contradicts that of the document regarding which improvement scenario is more realistic, sustainable, and has a bigger positive total sum of impacts. The authors should verify the conclusions.

In summary, while the study offers interesting practical improvement scenarios, the methodology description lacks clarity and consistency with the results presented. The authors should address the issues raised to improve the quality of the paper.

Reviewer 4 Report

This manuscript discusses improvement scenarios for a waste recycling program in Attica. The scenarios are compared based on the annual kilometer and time distance of the remote routes, the annual fuel cost decrease for the MGPs, and the annual reduction of CO2 emissions. The study has its value in practice; however, its theoretical value and contribution to knowledge is not clear. It looks more like a report or a project plan, rather than a scientific paper. In addition, it is not clear what the research purpose is? What research questions are to be addressed? What research methodology is applied? What is new in this study?

Overall, the paper needs substantial improvement in this regard before sending it to a journal.