Dry Sanitation Technologies: Developing a Simplified Multi-Criteria Decision Analysis Tool

Round 1

Reviewer 1 Report

The present paper proposes a tool namely SETEd for dry sanitation systems especially used in water scarce regions and low-income households. SETEds is a simplified tool, requiring rather few data, bringing an automatic multicriteria dimension analyses for different dry-sanitation technologies. The tool was applied to the Ambriz case study, a coastal  town in Northern Angola, in West Africa. This paper has a certain degree of innovation. I have, however, some comments for the authors.

1.      The abstract must be rewritten carefully to show the necessity of this research, its novelty and contribution, and its major findings. Write down the outcomes from the case study. “Multi-Criteria Decision Analysis (MDCA) should be MCDA”

2.      The main objectives of the research are needed to be defined at the introduction of the study.

3.      All the tables and figures are clear, understandable, and relevant; sources are indicated in each case well.

4.      The methodology contains a correct description of the methods applied, and is well-documented and supported. Nice to add an algorithm for the proposed method.

 

5.      There is no conceptual comparison with existing approaches, no discussion on the benefits and drawbacks the new approach. Thus discussions and comparative analyses should be added, also it is important to compare your method with the literature ones.

Author Response

The authors are grateful for the opportunity to resubmit a revised version of our manuscript. We thank the reviewers for the insightful comments to improve the quality of the manuscript, and we address each comment individually.

Most substantial revisions comprise rewriting part of the Introduction section to make the objectives of the research clearer, presenting a conceptual comparison with existing decision modelling approaches and highlighting the novelty of the research. In addition, the various dry sanitation solutions were explained in greater detail, along with our model’s criteria for exclusion of alternatives. An additional figure was also included, showing the different areas into which the Ambriz city (case study) has been divided.

Apart from that, minor adjustments were made to the text to make it clearer to the reader, according to reviewers’ comments. Also, some tables were reorganized for the same effect.

Incorporating all the suggestions and clarifications, we are confident that the manuscript has significantly improved, making it considerably more attractive to a wider readership.

Detailed answers to reviewers ensue in the following pages. The authors the received comments in black type and our replies follow in blue colour. All changes to the original manuscript are tracked.

 

 

Reviewer 1

The present paper proposes a tool namely SETEds for dry sanitation systems especially used in water scarce regions and low-income households. SETEds is a simplified tool, requiring rather few data, bringing an automatic multicriteria dimension analyses for different dry-sanitation technologies. The tool was applied to the Ambriz case study, a coastal town in Northern Angola, in West Africa. This paper has a certain degree of innovation. I have, however, some comments for the authors.

1. The abstract must be rewritten carefully to show the necessity of this research, its novelty and contribution, and its major findings. Write down the outcomes from the case study. “Multi-Criteria Decision Analysis (MDCA) should be MCDA”.
2. The main objectives of the research are needed to be defined at the introduction of the study.
3. All the tables and figures are clear, understandable, and relevant; sources are indicated in each case well.
4. The methodology contains a correct description of the methods applied, and is well-documented and supported. Nice to add an algorithm for the proposed method.

 5.There is no conceptual comparison with existing approaches, no discussion on the benefits and drawbacks the new approach. Thus discussions and comparative analyses should be added, also it is important to compare your method with the literature ones.

 

Responses:

The authors thank the reviewer for the time and effort dedicated to review the manuscript and for the comments and suggestions to improve it.

Point 1: MCDA was replaced by MDCA along the text, as appropriate, and the abstract was improved on order to emphasise the importance of the research, the novelty and major findings, as follows:

“Safely managed sanitation is indispensable for societies to ensure public health, environmental protection, and economic and social development. This could be achieved, in large areas of the World, through dry sanitation systems. In dense peri-urban areas, the achievement of safe sanitation necessitates a comprehensive faecal sludge management (FSM) service chain, surpassing the mere provision of latrines.

This research introduces an automatic Multi-Criteria Decision Analysis (MCDA) approach, which focuses on the particular interface/storage stage of the FSM service chain. The tool aims to support the decision-making process, and may be especially useful in the early stages of sanitation planning, by comparing different technologies with potential application in low-income countries. It includes different criteria and parameters for the Social, Economic, Technical, and Environmental dimensions of dry sanitation options (SETEds), being adaptable to different contexts and to different priorities. The main key strengths of the tool were found to be its minimal data requirements and ability to customize operation and maintenance cost parameters. These features are particularly relevant in data scarce contexts, where traditional models may lead to unreliable recommendations or lack of solution ownership by users. The tool was applied to the Ambriz case study, a coastal town in Northern Angola, in West Africa. The obtained results are analyzed and evidence how the tool’s application provides technology recommendations aligned with the site and community characteristics.”

Point 2: The main objectives of the research were already stated in the Introduction section, Lines 41-51. However, the paragraph was rewritten for enhanced clarity, as follows (Lines 57-65):

“(..) The primary purpose of the tool is to assist in infrastructure planning, by offering a systematic comparison of various sanitation technologies tailored to different areas within the city. This is particularly relevant since low-income urban and peri-urban areas often exhibit considerable variations in factors such as per capita water consumption, population density, financial resources, energy availability, communication infrastructure, road quality, and accessibility. SETEds is specifically designed to aid in the selection of technologies for the user interface and containment, within and pre-treatment stages within the faecal sludge management service chain.”

Point 3: OK. Thanks

Point 4: OK Thanks

Point 5: The discussion section was revised in line with this comment as follows (Lines 682-725):

“Existing models for sanitation technology selection, such as eCompendium, Santiago or FSM Toolbox, for example, while providing valuable contributions to the sector, often suffer from drawbacks, such as limited adaptability to data-scarce environments, inflexible cost assumptions, dependence on internet connectivity or the need for users with advanced expertise in sanitation.

Ecompendium by Emersan requires numerous inputs, which implies low adaptability to data scarce environments. It provides the user with possible technologies for each step of the service chain, but it does not provide a comparative analysis between the outputs.

Santiago’s inputs are meant to be obtained in workshops with the communities. Santiago has an editable database, so it can include new technologies as they arise. It provides some options of full sanitation service chain viable sequences, which the decision makers then decide from. SETEds focuses only on one step of the service chain, but, on the other hand, it does not require the user to make a comparative analysis from its outputs. It provides a small amount (5 or less) of technologies suitable for the context, rated from 1 to 5, with a clear vision of which technology the tool determined as the most suitable and in which order the others follow.

The tool by Bouhabid and Louis or the FSMToolbox are very adaptable and complete, but require heavy data input. In addition, the first only determines possible solutions, not ranking them or selecting the most suitable, while the latter requires the user to create an account in the platform and internet connection.

SETEds attempts to address critical gaps prevalent in current sanitation technology selection tools. Firstly, one of its key strengths is its minimal data requirements from the user concerning local conditions. This characteristic is particularly valuable in the context of low-income countries where access to comprehensive and up-to-date information is oftentimes very limited or even unavailable. Traditional models may often struggle with data scarcity, leading to unreliable recommendations or lack of solution ownership by users. SETEds aims to overcome this limitation by reducing the burden on users to provide extensive data inputs.

SETEds empowers users by allowing them to customize investment and operation and maintenance cost parameters. This feature facilitates precise and adaptable planning of sanitation systems, aligning the available financial resources and income levels of the communities they serve, as well as a better understanding of how model results are influenced by changing those parameters. In contrast, models which employ fixed cost assumptions can lead to unrealistic or impractical recommendations in the face of budget constraints, commonly encountered in low-income settings.

In addition, SETEds sets itself apart by its minimal technological requirements, as it operates efficiently with just a standard computer device and basic computational skills, utilizing Microsoft Excel as its platform, not requiring internet access. This accessibility ensures that the tool can be employed even in areas with limited digital infrastructure, expanding its usability to a broader user base.

While SETEds presents numerous advantages, it is important to acknowledge that there may be certain setbacks and limitations associated with its usage, due to the assumptions and simplifications used in its formulation, the fact that it focuses solely on one step of the sanitation chain or the number of solutions to choose from.”

 

Reviewer 2 Report

General comments: The article refers to a very interesting topic that is indeed of utmost importance in several parts of the world, especially in developing countries. Tools such as the presented in this article are useful to support decision making, and I think we need more research in this area. However, I have some comments that I hope could improve the current version of the manuscript.

 

1.         The introduction seems too condensed. A brief overview of onsite sanitation is needed. There should also be an introduction to the issue of dry sanitation around the world and its role in the onsite sanitation.

2.         Figure 1 requires a more detailed explanation of the various dry sanitation technologies. In fact, the entire paper focuses on only five technologies. These technologies, despite are simple, need to be explained in detail.

3.         When it comes to the exclusion criteria, it would be appropriate to provide more references to the works on the basis of which these criteria were established.

4.         A map showing the different areas into which the city has been divided would be desirable. There is also no mention of the population of Ambriz.

5.         An important point in the paper: It is not clear if the assessment was done by the research team in an internal workshop or if there was any interaction with the community. Please explain in more detail the different steps in which the assessment was done in the case study.

Author Response

The authors are grateful for the opportunity to resubmit a revised version of our manuscript. We thank the reviewers for the insightful comments to improve the quality of the manuscript, and we address each comment individually.

Most substantial revisions comprise rewriting part of the Introduction section to make the objectives of the research clearer, presenting a conceptual comparison with existing decision modelling approaches and highlighting the novelty of the research. In addition, the various dry sanitation solutions were explained in greater detail, along with our model’s criteria for exclusion of alternatives. An additional figure was also included, showing the different areas into which the Ambriz city (case study) has been divided.

Apart from that, minor adjustments were made to the text to make it clearer to the reader, according to reviewers’ comments. Also, some tables were reorganized for the same effect.

Incorporating all the suggestions and clarifications, we are confident that the manuscript has significantly improved, making it considerably more attractive to a wider readership.

Detailed answers to reviewers ensue in the following pages. The authors the received comments in black type and our replies follow in blue colour. All changes to the original manuscript are tracked.

 

 

Reviewer 2

General comments: The article refers to a very interesting topic that is indeed of utmost importance in several parts of the world, especially in developing countries. Tools such as the presented in this article are useful to support decision making, and I think we need more research in this area. However, I have some comments that I hope could improve the current version of the manuscript.

1. The introduction seems too condensed. A brief overview of onsite sanitation is needed. There should also be an introduction to the issue of dry sanitation around the world and its role in the onsite sanitation.
2. Figure 1 requires a more detailed explanation of the various dry sanitation technologies. In fact, the entire paper focuses on only five technologies. These technologies, despite are simple, need to be explained in detail.
3. When it comes to the exclusion criteria, it would be appropriate to provide more references to the works based on which these criteria were established.
4. A map showing the different areas into which the city has been divided would be desirable. There is also no mention of the population of Ambriz.
5. An important point in the paper: It is not clear if the assessment was done by the research team in an internal workshop or if there was any interaction with the community. Please explain in more detail the different steps in which the assessment was done in the case study.

Responses:

The authors thank the reviewer for the time and effort dedicated to review the manuscript and for the comments and suggestions to improve it.

Point 1- This comment diverges from the feedback received from other reviewer, regarding the length and extent of information that should appear in the Introduction section. However, the Introduction was rewritten: In line with this comment, in the Introduction section, an overview of onsite sanitation, particularly dry-on site sanitation around the World was included, as follows (Lines 44-55):

“The year of 2020 was the first when the percentage of the world population served by onsite systems was higher than the percentage of population served by sewered sanitation, with the onsite services growth coming mostly from rural areas. From 2000 to 2020, the rate of sewered solutions increased 0.51% per year, while onsite sanitation rate (measured by the sum of the individual increasing rates of septic tanks (0.46%) and improved latrines (0.25%)) increased 0.71%. Also in 2020, 34% of the people with access to safely managed sanitation services had it through sewered sanitation, while 20% had it through on-site sanitation. [1]

However, focusing on the particular situation of Sub-Saharan Africa, Central and Southern Asia and Oceania, onsite sanitation is more common than sewered sanitation even in the urban areas. In urban areas, septic tanks are increasing at a rate of 0.24% per year and dry pit latrines at 0.06%, while sewers are increasing at 0.14% [1].”

 

Point 2: In line with the comment, the technologies were explained in greater detail, as follows (Lines 170-192):

“Detailed explanations of the different dry sanitation options can be found in references 2, 11, 20, 22. Nonetheless, a brief description for each alternative considered in SETEds is presented, based on the findings of those authors. An improved single pit is a pit dug on the ground for the excreta to fall in after the toilet is used.  It must have a proper slab to ensures separation of excreta from human contact.

VIP stands for Ventilated Improved Pit, which is an improvement comparing to the Improved single pit as it works the same way but in the case of the single VIP there is a specific ventilation channel for the odours and flies to escape the pit. The Double VIP is, as the name implies, a technology constituted by two ventilated improved pits. The superstructure where the user interface has place is changed from one pit to the other, staying in the pit that is filling while the filled pit is draining, degrading, and reducing volume.

The Fossa Alterna technology consists of a double pit with alternating use. When one pit is filling the other is full and the excreta is degrading, and then can be removed manually, just like in the Double VIP technology. The difference from Double VIP to Fossa Alterna is that the Fossa Alterna is designed to produce compost/Ecohumus, while the main purpose of the Double VIP is to collect the excreta, and, only if possible, reuse the content after it rested in the full pit. The Fossa Alterna pits are shallow pits with around 1.5m depth.

The Container-based toilet is a toilet, most of the times urine diverting, that stores the excreta in containers that are sealable and removable on a regular basis. The containers are above ground, one for the urine and another for the faeces, both inside the structure of the toilet. It requires a collection team that goes door to door swapping the full containers for empty ones.

Point 3: OK, Rather concise justifications were given in lines 322 to 325 of the original document. The thresholds set in the exclusion criteria were derived either from national and international references or from co-authors experience gathering in sanitation projects for African countries. The value 3 m in criterion C1 was adopted from [26]. The value 500 m in criterion C5 and the minimum areas for implementation in criterion C3 were derived from [11]. The values 7 years in criterion C2, and 30 inhabitants/ha in criterion C4 were the result of the co-authors’ experience in developing sanitation projects in Sub-Saharan Africa with the adopted criteria discussed with local stakeholders [24, 25, 27, 28]. This additional information was inserted in the paper (lines 352-358)

Point 4: A map was added (figure 5), as well information about the urban and peri-urban population in Ambriz. According to the last Census (2014) the population in that area was of 11 640 inhabitants, with projected growths to 14 460 inhabitants in 2020 and 27 330 inhabitants in 2040. The information was included in the paper as follows (Lines 500-502):

“According to the last Census (2014), the population in the urban and peri-urban area of Ambriz was of 11 640 inhabitants that year, with projected growths to 14 460 inhabitants in 2020 and 27 330 inhabitants in 2040 [31].”

Point 5: The information about Ambriz is sourced from a sanitation project conducted by Hidra et al. [31] which also involved the participation of paper’s co-authors. In fact, interaction with the community involved multiple meetings and two workshops with local stakeholders, encompassing national and regional wastewater service decision makers, sanitation experts and local communities.

More detailed explanations were included in the paper as follows (Lines 472-478):

“Interaction with the community involved multiple meetings, enquiries and two workshops with local stakeholders, encompassing national and regional wastewater service decision makers, sanitation experts and local communities, within the scope of the sanitation project conducted by Hidra et al. [31]. Workshops dealt with: a) Existing situation and sanitation challenges and b) Planning criteria, and feasibility options. Overall, 339 people were involved in the participatory processes”.

 

Reviewer 3 Report

Dear authors,

I consider your contribution to be improving decision making according to the availability of resources in countries with limited economy resources. I also appreciate your concern for people to have better sanitary services. In the word document you will find some observations and suggestions in favor of the document.

 

Best regards

Comments for author File: Comments.pdf

Author Response

The authors are grateful for the opportunity to resubmit a revised version of our manuscript. We thank the reviewers for the insightful comments to improve the quality of the manuscript, and we address each comment individually.

Most substantial revisions comprise rewriting part of the Introduction section to make the objectives of the research clearer, presenting a conceptual comparison with existing decision modelling approaches and highlighting the novelty of the research. In addition, the various dry sanitation solutions were explained in greater detail, along with our model’s criteria for exclusion of alternatives. An additional figure was also included, showing the different areas into which the Ambriz city (case study) has been divided.

Apart from that, minor adjustments were made to the text to make it clearer to the reader, according to reviewers’ comments. Also, some tables were reorganized for the same effect.

Incorporating all the suggestions and clarifications, we are confident that the manuscript has significantly improved, making it considerably more attractive to a wider readership.

Detailed answers to reviewers ensue in the following pages. The authors the received comments in black type and our replies follow in blue colour. All changes to the original manuscript are tracked.

 

 

Reviewer 3

I consider your contribution to be improving decision making according to the availability of resources in countries with limited economy resources. I also appreciate your concern for people to have better sanitary services. In the word document you will find some observations and suggestions in favour of the document.

Responses:

The authors thank the reviewer for the time and effort dedicated to review the manuscript and for the comments and suggestions to improve it. We quote the received comments in black type and our replies follow in blue colour

 

Observations and suggestions

Line 7. Please complete the address, I found in internet address this for Hydra Hidraulica Campo da bola, R. Afonso Botelho 8A, 1600-117 Lisboa, Portugal

The address was completed as follows: Hidra, Hidráulica e Ambiente, Av. Defensores de Chaves, 31 – 1º Esq. 1000-111 Lisboa, Portugal

Line 8. Please complete the address, I found in internet this for DNA. Rua 21 de Janeiro, Sector A, Quarteirao 2, Casa 12 (Ex-escritorios do COCAN), Bairro Morro Bento„ Luanda, Angola.

The address was completed as follows: Direção Nacional de Águas (DNA) de Angola, Condomínio Dolce Vita, Prédio 1 D 6 andar, Luanda, Angola

Line 26. The introduction presented is very complete, however, following the indication of the authors guide, it could be delimited to have a more concise introduction.

The introduction was rewritten, according to the comments of other reviewer in terms of increasing the clarity of this section, as follows:

Lines 44-55: “The year of 2020 was the first when the percentage of the world population served by onsite systems was higher than the percentage of population served by sewered sanitation, with the onsite services growth coming mostly from rural areas. From 2000 to 2020, the rate of sewered solutions increased 0.51% per year, while onsite sanitation rate (measured by the sum of the individual increasing rates of septic tanks (0.46%) and improved latrines (0.25%)) increased 0.71%. Also in 2020, 34% of the people with access to safely managed sanitation services had it through sewered sanitation, while 20% had it through on-site sanitation. [1]

However, focusing on the particular situation of Sub-Saharan Africa, Central and Southern Asia and Oceania, onsite sanitation is more common than sewered sanitation even in the urban areas. In urban areas, septic tanks are increasing at a rate of 0.24% per year and dry pit latrines at 0.06%, while sewers are increasing at 0.14% [1].”

Lines 57-65: ““(..) The primary purpose of the tool is to assist in infrastructure planning, by offering a systematic comparison of various sanitation technologies tailored to different areas within the city. This is particularly relevant since low-income urban and peri-urban areas often exhibit considerable variations in factors such as per capita water consumption, population density, financial resources, energy availability, communication infrastructure, road quality, and accessibility. SETEds is specifically designed to aid in the selection of technologies for the user interface and containment, within and pre-treatment stages within the faecal sludge management service chain.”

Line 34. Authors mention a figure, which figure is this, please include the correspondence number and the figure.

Previous line 34, new line 41: Figure was used as synonym of “number”. Changed for “these numbers” for more clarity.

Line 65. To have continuity to introduction section, please place the numbering 1.2 instead 2. Use italic typography as authors guide indicate.

Previous line 65, new line 83: numbering corrected for 1.2, formatted with italic typography.

Line 98 change "that a certain technology required from a community" by that a particular technology requires by a community.

Previous line 98, new line 116: “certain” changed for “particular”.

Line 141 and 142. I consider more appropriate "SETEds is a simplified tool that requires relatively little data and provides automatic multi-criteria dimensional analysis for different dry sanitation technologies".

Previous lines 141 and 142, new lines 159 and 160: Changed for “SETEds is a simplified tool that requires relatively little data and provides automatic multi-criteria dimensional analysis for different dry sanitation technologies”.

Line 162. To continue with the numerical sequency place 2.2 before the subtitle, use italic. Typography as authors guide indicate.

Previous line 162, new line 278: 2.2 placed before the subtitle, with typography as indicated in the authors guide.

Line 169. Please take out the parenthesis [10]

Previous line 169, new line 199: parenthesis removed.

Figure 1. Is a suggest. Observation of different angles of a single VIP in Sumbe, Angola or if the authors have some picture of SVIP, Double Ventilated Improved Pit (DVIP), Fossa Altema (FA) and Container-Based Toilet (CBT), authors could have a best figure. If you have these pictures, I suggest distingue each picture with a letter to located it.

Figure 1: legend changed as suggested, for “Observation of different angles of a single VIP in Sumbe”.

The authors do not have additional images (not requiring copyright permission) for all options, and therefore these were used, as they represent original content.

Table 1. In the first line include the country Angola. As a foot note indicate in empty columns data not found.

Table 1: country Angola added. Instead of “data not found” the empty spaces were signalled with NA for Not Applicable, because, for example, in the case of improved single pit, the absence of operation and maintenance costs is because it was an assumption of the methodology to consider that, once full, the pit would be sealed and covered, with no sludge removing service required, and therefore no costs.

Line 215. Please follow the author's guide as Materials and Methods.

Previous line 215, new line 249: Materials and Methods revised according to the author’s guide

Line 247. Excuse me, I do not clearly understand what the authors mean when they mention SETEds weights. Do you refer to the value in terms of the utility of the survey? Could you be more explicit please. Maybe authors referee to the percentage occupied by financing in the survey.

Previous line 247, new line 281: Criteria preference weights represent the relative importance or significance assigned to each of the criteria used to evaluate and compare the different alternatives. These weights reflect the decision maker's or stakeholders' preferences and priorities regarding the criteria.

This explanation was included in the manuscript in section 2.2 (Lines 278-294)

Line 215. Please add and Methods as indicate the authors guide.

Done.

Line 350. It is suggested that Tables 7 and 8 be placed under the descriptions of the social and economic dimensions, Tables 9, 10 and 11 under the technical dimension and Table 12 under the environmental dimension.

Previous line 350: tables placed as suggested.

Table 8. In the last column, you referred to the E3 score in the criteria. If this is correct, please change T3 to E3.

Table 8: corrected for “E3”.

Table 12. For a better understanding it is suggested to add the title Permeability in the second column, since it is an important parameter, and it is the one indicated.

Table 12: title “permeability” added to the second column.

Table 14. The cost of the 0 & M in the improved of the single pit is null? If it is correct, please include the value 0 or falling that add ND not determined.

Table 14: It is null because it is recommended only for areas with low population density. When it is full, it should simply be sealed and covered, with no sludge removing, hence no operation costs. 0 was added to table 14.

Table 14 and 15. I consider that tables 14 and 15 are part of the results obtained in the case study of the Ambriz and should be presented in the appropriate section.

Table 14 shows the results of the cost analysis that was carried out, as to include total costs (default investments plus default O&M costs) in the tool. It is an integral part of how the model was built and does not correspond specifically to the case study application.

As for Table 15, we totally agree with the suggestion and changed it to the Results Section.

Line 439. I consider that the case study presented is part of the Materials and Methods section, so I suggest that number 3.7 be placed in the case study and the subsection sub, sub-title the corresponding number.

Previous line 439, new line 467: Case study included in Materials and Methods and subsequent numbering changed

Figure 3. As a suggestion, add some important information at Location of Ambriz, perhaps located in Central Africa on the south of the Atlantic Ocean at S 7° 51' 47.1024" latitude and E 13° 7' 9.3216" longitude.

Figure 3: information added. “The city is located in Central Africa, on the south of the Atlantic Ocean, at S 7° 51' 47.1024" latitude and E 13° 79.3216" longitude.”

Figure 4. Maybe you can add Promedial household in Ambriz

Figure 4: changed for “Promedial household in Ambriz”

Line 554. To have more visualization of the data, it is more appropriate to put in this part of the manuscript the table 14 and the corresponding descriptive text (see materials and methods section).

Table 14 shows the results of the cost analysis that was carried out, as to include total costs (default investments plus default O&M costs) in the tool. It is an integral part of how the model was built and does not correspond specifically to the case study application.

Line 581. To have more visualization of the data, it is more appropriate to put in this part of the manuscript the table 15 as well as the corresponding descriptive text (see materials and methods section).

We totally agree with the suggestion and changed table 15 to the Results Section.

Table 16. The correct date according to references is MINEA., 2023 not Mocamedes, please correct it.

Table 16: corrected for MINEA

Table 17. Please include the value 0, ND not determined, NA, not applicable in improved single pit and the respective foot note.

Table 17: NA added, as well as the footnote

Table 18. Please include the value 0, ND not determined, NA, not applicable in improved single pit and fossa alterna and the respective foot note

Table 18: NA added for single pit. For fossa alterna it was not added because it is not that it is “not applicable” or “not determined”, it is that not all the references used for the costs systematization presented values for both investment and OM.

Line 666. Please include the corresponding back matter, author contributions, funding, acknowledgments, and Conflicts of Interest.

Previous line 666, new line 750: Corresponding back matter, author contributions, funding, acknowledgments, and Conflicts of Interest included.

Please adapt the bibliography as indicated in the Author's Guide. Start with the author's surname followed by the initials of the first name. As example a recently free published paper in Sustainability MDPI. https://www.mdoi.com/2071-1050/15/17/12973

2. L. Strande, M. Ronteltap................. to Strande, L.; Ronteltap, M....................

3 . E. Perard change to Perard, E.

6. A., Bouabid,....., change to Bouabid, A.; etc........

Changed according to the example.

 

 

Round 2

Reviewer 2 Report

The authors have taken into account all my comments to the previous version.

Author Response

Manuscript ID: sustainability-2557845

Type: Article

Title: Dry sanitation Technologies: Developing a simplified Multi-Criteria Decision Analysis tool.

Authors: Margarida Fidélis Santos *, Carolina Pires Castro, Rita Ventura Matos, Liliana Alves, José Saldanha Matos

 

Responses to comments and suggestions for minor revision, from the editor

The authors are grateful for the opportunity to resubmit a minor revised version of our manuscript. We thank the editor for the comments to improve the quality of the manuscript, and we address each comment individually. The reviewers have not included further comments, accepting the responses of the first revision round.

Apart from that, minor adjustments were made to the text to make it clearer to the reader.

Incorporating all the suggestions and clarifications, we are confident that the manuscript has significantly improved, making it considerably more attractive to a wider readership.

Detailed answers to each comment are presented in the following pages. The authors the received comments in black type and our replies follow in blue colour. All changes to the original manuscript are tracked.

 

 

Please make before reference list a list of all abbreviations with their explanations.

Response: A list of all abbreviations and respective descriptions was included before the reference list (lines 854-873).

 

Table 8: Why container based toilets with compost acceptance has lower scores than if that no compost.

Response: We apologize for the editorial mistake. Container-based toilets with compost reuse acceptance have a higher score for criteria S3, E3 and A3 then when compost reuse is not accepted. Therefore, the score values were switched on table 8. The model is correct - therefore, the results of the case study application are not affected.

 

Summer: when the area has summer (line 533)?

Response: Between May and September. But we mean not exactly the summer, but the dry period. This information was corrected in lines 509-511 of the manuscript, as follows:

“The brooks in Ambriz have typically no flow in the dry period, between May and September, apart from Loge River, serving as the drainage system for the runoff of surface waters”

 

Table 13: explain! In many cases you have no space between two reference numbers in text.

Response: We are not sure of understanding the comment An explanation of the attributed fixed values is given previously to the presentation of table 13 (lines 422-438)

“Regarding fixed values for criteria S1, S2.2, T2 and T3, they are presented on table 13 and its classification is detailed next. For criterion S1 (Odor potential), ISP receives the lowest score since no cover material is added after each use and no ventilation equipment exists to reduce odors. FA also does not have ventilation equipment, but odors are reduced through the addition of cover material after each use. DVIP and SVIP receive the highest scores due to the existence of ventilation and CBT also, since the collection frequency is much higher, reducing the presence of odors. For criteria S2.2 (Health risks: flies and mosquito potential), the classification follows the same logic: ventilated solutions, as well as CBT, due to the isolation of the faecal sludge, receive the highest score and the remaining solutions receive the lowest score.

For criterion T2 (Complexity and difficulties of construction), DVIP receives the lowest score since requires a more complex construction, with a superstructure and a ventilation pipe, as well as two pits. FA also requires the construction of two pits, receiving the second lowest score. SVIP has a similar construction to DVIP, but only requires building one pit. ISP does not require a superstructure, simplifying the construction process. CBT has an industrialized construction, not implying complexity in the construction process for its users, therefore receiving the highest score.

For criterion T3 (Complexity of O&M activities), SVIP and DVIP have the lowest score due to the necessity of maintaining the superstructure in a dark environment and the ventilation pipe cleaned, to avoid flies, mosquitoes and odors presence. CBT receives a classification of 3 due to the need for a more frequent collection of faecal sludge, compared with the other solutions. FA and ISP practically do not require any maintenance, apart from the collection moment, receiving the highest score.”