Sustainable Multi-Objective Models for Waste-to-Energy and Waste Separation Site Selection

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The presented contribution is interesting from the view of analyzed area, as well as from the view of the analyzed regions. Finally yet importantly, due to the aspects of the solving, the paper is interesting also from the view of sustainability.

The authors written the paper clearly and in understandable way, structure of the paper is easy to be followed up. I evaluate the paper positively also due to the following strong part of the paper:

-          Authors declared not only main outputs of the paper, but also possibilities how to verify their possible use in the practice

-          The contribution of the paper is visible for the publishing in the journal

-          The goal of the paper is determined only after clear explanation of present state of problem solving, limitation of the research

-          In the literature review authors clearly determined trends in the world as well as gap in the literature

-          During the research authors used strong mathematical apparatus, which increase the scientific character of the paper

-          The research is done through more level – from the level of types of waste collection, from the level of individual regions, etc.

 

In spite of mentioned positive characteristic of the paper, I recommend authors to make small adjustment of the paper, which could increase its quality:

-          Key words – not repeat words from the title, mention the other ones

-          When speaking of environmental and economic sustainability, please, consider also social aspect (TBL approach – triple bottom line)

-          Please, mention the source for illustrations (own processing, software, reference, etc.?)

-          Authors could separate from part Result data of the research (for example Figure 3 is presentation of data and materials)

-          Small English language improvement

-          The equation are readable, however, I recommend to unify the legend for all equations

-          Please, verify the numbers in tables and figures, for example Table 6 – is it 12148.81 or 12,148.81?

Comments on the Quality of English Language

Please, rewrite some sentences, for example:

- page 11 "and is according to" - what "is"?

page 14 "As can be seen" - very simple sentence.

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Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript focuses on the development of models to determine the location of collecting and transformation centers for wastes. The topic is relevant from the viewpoint of planning the transformation of wastes. However, it requires to be modified before to be accepted for publication. Please find specific comments in next lines.

Line 44. Waste to energy approach has several years being used in different regions all around the world; I suggest to modify this sentence.

Line 59. Seems few waste production; please verify and indicate to what corresponds this amount of waste (organic, solid, recyclable, …).

Figure 1. Please fix the units for capacity of power plants (MkW/h is incorrect)

Line 92. “It appears…” It is a redundant sentence, is the same said in the previous phrase.

Line 94. Why hydrogen? Please justify.

Section 2.1. It is suggested that the authors present a concluding remark related to the literature review; for example, what are the dimensions of the reported plants, the amount of treated waste, the amount of produced energy, and some other relevant details.

Line 188-190. “The arrival of waste at each node to undergo the energy conversion process from industrial centers (waste collection and sorting) follows a Poisson process with a rate of ?i” Is this distribution a standard characteristic of arrival waste? If yes, a reference is required. If not, authors should justify the assumption.

Line 218. “Also, the WtE center has the task of converting biological WtE in the pyrolysis process” This sentence is confusing; the authors refer to biological waste? Is it organic waste, maybe? What will be processed by pyrolysis. Please clarify.

Section 3.1.2. The authors claim that “This function is intended to reduce pollution levels and the release of pollution to the environment”. However, there is not environmental indicators; in fact, all the functions have indirect influence on environment. It is recommended to reformulate the objective of this function. In addition, since the waiting time cost depends on the waste processing time, it is recommended to briefly mention the alternatives for the transformation including an estimation of this time processing.

Section 3.3. From my viewpoint, the dynamic model requires a solid justification. It seems obvious that the waste shipments go to the nearest center, even in the static model.

Table 2. Why the distance from Ci to Ci is 1? It should be 0, is it not? In addition, it is suggested to include the proposed locations in the map of Figure 3.

Line 372. The inequality seems incorrect, authors require to express 0.5<k1<1? Please clarify. In addition, how this k1 is obtained? I mean, how the quality and risk of pollution are determined? Please mention it somewhere in the manuscript.

Line 373-374. Same comments as for k1.

Line 380-390. To what corresponds the cost units? Please briefly explain how the cost units were determined.

Table 5. Authors should explain why there is not difference between results from models for most of cases.

Table 6. Please briefly describe how the values for parameters w1 and w2 were selected for the sensitivity analysis.

It is required to include the variable and the respective units in vertical axes of figure 4 and 5; by the way, figure 5 is named figure 4, fix it.

Line 430. Why 0.45 is a common value in the literature; please provide a physical interpretation of the value. Also, why only one different value is considered for the sensitivity analysis. From my viewpoint a single data is not enough to evaluate the effect of the parameter on the objective function.

The discussion should provide some qualitative comparisons wrt similar works, this helps to identify the advantage of the proposed models.

Lines 457-458. “The DAM is likely to be more efficient due to capacity issues that will arise.” There is not evidence to support this sentence. From the presented information, the DAM provides the same result as the FAM. To support the referred sentence, it is required to evaluate at least one realistic scenario where the advantage of the DAM is evident; otherwise, it is not possible to determine that this model offers advantages.

 

Lines 465-466. The recommendation seems correct, but it would be more useful to indicate how these locations could be done.

Line 469. Again, there are not environmental indicators to know how many the emissions are reduced. This recommendation should be expressed in terms of time or costs.

Lines 472-475. As for the first recommendation, it should be more useful for the decision makers to know how to find the optimal parameter beta.

Comments on the Quality of English Language

No additional comments.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have provided adequate answers for most of comments in first round. There are still few requirements:

Line 59. “approximately organic and solid 603 tons of waste”, fix the sentence.

Regarding the production of municipal wastes in the different provinces, I’m still thinking the reported values are few. Considering a population of 1 million inhabitants and a daily generation of 650 g percapita, the produced wastes are 650 ton per day and 19 500 ton per month. Please check again that information.

In figure 1, again, the units (Mkw/h) in vertical axe are incorrect; please fix it.

Please void first person (we, our, etc.) in sentences.

Line 402-405. How this k1 is obtained? I mean, how the quality and risk of pollution are determined? Please mention it somewhere in the manuscript. Same comments for k2.

Regarding costs, is it possible to link the units considered in the manuscript with an international currency (dollar, euro, or some other)?

Lines 535-145. This paragraph should appear in the Discussion section.

Author Response

Please see the attachment

Author Response File: Author Response.pdf