Financial Feasibility Analysis of Residential Rainwater Harvesting in Maringá, Brazil
Round 1
Reviewer 1 Report
authors have performed thorough research on the topic. In some places the methodology adopted is not clear regarding economic evaluations. For example
Equation 7 for the payback period is a simple payback period whereas it is stated as discounted payback period.
Equation 8 for NPV mentions I as an inflation factor where it should be interest rate (minimum attractive rate of return). This equation is multiplying K with the sum term which should be corrected.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
This study aims to evaluate the financial feasibility of residential RWH in Maringá, Brazil. The authors compare indirect and direct rainwater distribution schemes and use 3 main indicators in their methodology. One major concern is, the novelty and the comprehensiveness of this study haven’t been clearly proposed at present. Please consider the following comments:
Abstract: This section needs more results and a more specific conclusions/statement of broader impacts. Here, and throughout the manuscript, try to reduce the use of unsupported, qualitative, and vague descriptions, such as “more comprehensive”, “a significant correlation” or “may contribute”. Focus on specific and quantitative statements, even when setting up the motivation, and providing enough background to make and substantiate claims like these.
Lines 26-29: I don’t understand the logic between the two sentences.
Lines 33-38: This paragraph seems to propose the goal of this study. However, the goal/statement of purpose needs to be strengthened. It is too vague at present. I keep asking “so?” when I read these sentences.
Lines 40-45, 53-56: I don’t see the necessity of these two paragraphs.
Lines 57-114: This is the literature review part. Each paragraph introduces one or two studies, but the connection between studies is not obvious. It now seems just a list of studies. I suggest organizing previous studies in categories. Summary is also necessary for readers to understand the research gap and the purpose of the study.
Figure 2 and 3: They are using the same set of notations. Can these two figures be combined?
Equations 4-6: one nomenclature without repeated notations may be enough for these equations
Line 324: check the citation format.
Line 347: what are the 54 simulation scenarios?
Method: Currently, authors adopt 3 indicators in this study. The novelty of the methodology should be clearly stated.
Line 482-483: I suggest including the summary of feasibility indicators in the manuscript.
A discussion session with limitations and future directions is suggested.
Please check grammar and tense in the manuscript.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Following are my comments on this manuscript:
Abstract- it is weak and does not attract readers attention. Add stat figures from your results to build your case more strong and attractive.
Introduction- the intro needs more attention. Current form is not acceptable as there is no flow in the ideas. It seems the authors just added diff ref studies and made intro part. Moreover, the significance and need of study requires more attention.Methodology- why and how the current study area was chosen. Authors have used many equations but there are reference to none. Why is it so? Moreover, authors are suggested to add more details on the selection of methodology and why and how it was chose? What was its limitations? Add a flowchart for methodology to depict study processes. Result- the discussion and results is very weak. Add more recent papers to justify and compare your findings. How your results are different from other similar studies or how they are in compliance with previous studies. Conclusion- study limitations, theoretical and practical implications and future agenda is not covered and needs due attention of authors. It is suggested to add sub headings and add your thoughts in the light of your study.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
General comments:
Interesting topic to discuss about the financial analysis of RWHS. The objectives are clear but the problem statement is confusing. A lot of literatures were elaborated in the introduction but lack of summary table to emphasize the research gap.
Abstract
Lacking novel contribution and recommendations. What makes the research different from other RWHS financial analysis?
1. Introduction
Page 2 Line 49, 51, 58, 66, 71 and 90: Avoid using the term “The authors”, suggest to change to passive sentence.
2. Materials and Methods
Page 4 Equation 1, 2 & 3: Are those new equations? If no, please cite the reference.
3. Results
Page 9 Line337-338: average monthly rainfall is 60mm but average yearly rainfall is 1795mm? Please check.
Page 10 Line 371-381: Avoid using the term “The authors”, suggest to change to passive sentence.
Page 14 Line 478-483: Why are there cases with water demand lower than 2.1m3/month?
4. Conclusion
Avoid using the term “The authors” or “our”, suggest to change to passive sentence.
Lack of recommendations.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Now the payback period has been correctly presented as a simple payback period (SBP). To be precise, it is an incremental payback period as it takes into account the cost saving as a result of RWHS installation. Why did you not consider the benefits of the RWHS system in the calculation of SPB? That would give a payback period that can be compared with the useful life of 30 years. NPV formula shows the benefit term which is not used in the payback formala. There should be consistency between the formulas used. So either the payback formula to be used as presented then NPV formula should not use the benefits term. In that case the NPV will be the net present value of the costs alone.
The IRR formula cannot mathematically produce a result as it only provides the cost terms term. So the formula should provide a benefit term or this formula should be presented as an incremental IRR formula.
Also the formula for IRR is in terms of year as the timeline but the results are giving the IRR in terms of months. So either the formulas should be provided in terms on month or the results should be provided in years.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
All comments have been addressed.
Author Response
We are grateful for your careful review of our study. We appreciate your time and effort in contributing to improving our manuscript.
Reviewer 3 Report
I believe the manuscript is improved as compared to previous submission.
Author Response
We are grateful for your careful review of our study. We appreciate your time and effort in contributing to improving our manuscript.
Round 3
Reviewer 1 Report
The authors have revised the payback period equation and provided a reference to the original equation. However, the given equation is invalid based on the classical engineering economy concepts as it adds two cash flows at different times. The Yt-1 is a cash flow at time t-1 whereas the quotient term is cash flow in the present time if we consider p time units from now. These two amounts simply cannot be added. It is against the basic principle of the time value of money. The authors should provide a valid equation for the discounted payback period. The other two equations for NPV and IRR are now fine.
Author Response
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Author Response File: Author Response.pdf
