Impact of Gravity-Driven Membrane Filtration Water Treatment Systems on a Rural School in Indonesia

Round 1

Reviewer 1 Report

The manuscript entitled “Impact of Gravity Driven Membrane Filtration Water Treatment Systems on a Rural School in Indonesia” explores the impact a GDM water treatment system on the water quality and student health for Indonesian children in a rural school. It demonstrates efficacy of filtration performance after several months. There are several areas in the manuscript that deserve major improvements. Following comments are provided for possible improvements in paper.

• The abstract does not provide the connections between problem statement, research gap and objectives. 

• updated literature review is missing in introduction.

• make this manuscript comprehensive by adding updated discussion as per updated articles in the literature. 

• The graphics representation of the manuscript needs to be revised. The text font written inside the Fig’s could be same with the rest font of the paper. Figures gets blur when they zoom in.

• It would be better to add the properties of the membrane material to strengthen the study.

• How about elaborating the working principle of the GDM treatment.

• The pictorial representation of the laboratory experiment could be added.

• Extensively explain about the data collection and its experimentation conducted in lab.

• The results obtained can be useful for future research as well if the variables being researched are well-defined and their nature i.e., dependent, independent etc. is clarified in the methods section. Furthermore, how this study could be useful in future.

• It would be better to compare your results with the permissible limits given by Indonesian Ministry of Health.

• Certain things in the manuscript need attention i.e., data collection, tentative validation of values of treated water.

• It is recommended to make the classes of the different characteristics of the water i.e., chemical, physical, biological. It will bring an ease to understand the results.

• The GDM treatment would be placed in which set of treatment primary, secondary, tertiary. Provide some additional details.

• Focus the results and discussion on the scientific basis solely and support the statement by published articles. 

• Based on your results how would you prefer GDM then other conventional treatments. The key details should be added from the subject point of view. 

• The paper needs to well-structured even the sharp conclusion is missing.

 

 

Author Response

The manuscript entitled “Impact of Gravity Driven Membrane Filtration Water Treatment Systems on a Rural School in Indonesia” explores the impact a GDM water treatment system on the water quality and student health for Indonesian children in a rural school. It demonstrates efficacy of filtration performance after several months. There are several areas in the manuscript that deserve major improvements. Following comments are provided for possible improvements in paper.

• The abstract does not provide the connections between problem statement, research gap and objectives. 

The abstract text has been modified.

• updated literature review is missing in introduction.

Additional references have been added to the introduction.

• make this manuscript comprehensive by adding updated discussion as per updated articles in the literature. 

Changes have been made to the discussion section, Please note that many references related to Indonesian water quality  in the original draft have been taken from 2022 publications.

• The graphics representation of the manuscript needs to be revised. The text font written inside the Fig’s could be same with the rest font of the paper. Figures gets blur when they zoom in.

Figure one has been revised to improve the text font of the locations of interest.

• It would be better to add the properties of the membrane material to strengthen the study.

Text has been updated (line 126-129.

• How about elaborating the working principle of the GDM treatment.

This has been provided in the introduction along with references (line 69-75).

• The pictorial representation of the laboratory experiment could be added.

Please see the comment below. We have opted to only use narrative description of the methods employed as water quality analysis for the study used common protocols and techniques.

• Extensively explain about the data collection and its experimentation conducted in lab.

Methods utilized in the study are common protocols for the analysis of water quality. References have been provided in the text along with descriptions of the analytical methods used, and there were no novel methods utilized in this study. Some additional details have been provided to clarify collection volumes for chemical analysis (line 136-161).

• The results obtained can be useful for future research as well if the variables being researched are well-defined and their nature i.e., dependent, independent etc. is clarified in the methods section. Furthermore, how this study could be useful in future.

Our main analytical focus for data collected was to determine the efficacy of GDM filtration. These results have been provided in the text as well as in several tables (Table 4 and Table 5).

• It would be better to compare your results with the permissible limits given by Indonesian Ministry of Health.

This was noted in the original draft of the manuscript. Additional changes have been made to the text (Table 1, line 236-252).

• Certain things in the manuscript need attention i.e., data collection, tentative validation of values of treated water.

Water quality analysis was done using standard methods, and novel procedures for chemical and microbiological analysis were not explored in this study. As such, we did not consider the need to validate the methods used to generate the water quality data.

• It is recommended to make the classes of the different characteristics of the water i.e., chemical, physical, biological. It will bring an ease to understand the results.

Water quality can encompass a broad spectrum of potential contaminants. We focused on several chemical parameters of public health interest and bacterial fecal indicators. We sought to briefly summarize these in the results section as well as provide a summary in the discussion section (Line 288-324). 

• The GDM treatment would be placed in which set of treatment primary, secondary, tertiary. Provide some additional details.

Additional details have been provided in the text to clarify this (line 124-131). 

• Focus the results and discussion on the scientific basis solely and support the statement by published articles. 

We feel that in addition to summarizing the findings of our work, we also have provided several references of Indonesian water quality, burden and incidence of diarrhea in Indonesia, and the filtration efficacy of GDM technology employed in other studies (line 287-388).

• Based on your results how would you prefer GDM then other conventional treatments. The key details should be added from the subject point of view. 

We have discussed the advantages of the GDM system (low comparative lifetime costs to purchased bottled water, no energy requirement, and operational long lifetime (approximately 8 years), as well as limitations to GDM filtration systems (line 352-389).

• The paper needs to well-structured even the sharp conclusion is missing.

We have adopted a stance on providing a conclusion as per the journal author guidelines that a conclusion section is optional. As the manuscript currently provides a relatively focused study and a brief discussion section, we did not think an additional conclusion section was warranted. However, we will defer to the journal editorial decision and include a conclusion section if they deem it necessary.

Reviewer 2 Report

The manuscript by Sudiyani et al. is an interesting work describing the practical utilization of a GDM system aiming to improve the water quality in rural areas. A minor revision is required with several suggestions below:

 1) Line 39-41: The declined mortality may not be simply attributed to improved water quality. Actually, the availability of more vaccines is another important factor. Approximately 5.1 million child deaths in 1990 could be ascribed to vaccine-preventable diseases. From this point of view, the improved water quality may help to protect the children without vaccination. Please report more related data here and enrich the discussions.

 2) Line 164-165, “students were allowed to freely consume water from the GDM treatment system under the supervision of school staff.” Would the students drink the water directly or drink before boiling? Please add more details.

 3) Line 217, Table 3: For the question of “Where does the water you drink at school come from?”, the answers were “Bottled, bought, supplied by school or Home”. Please describe the classifications in more details. For example, where did the bottled water come from? And what was the form of the “Bought” water? And what is the classification if the water supplied by school was in the Bottled form?

 4) Line 217, Table 3: For the control group, the source of water supply also changed obviously. More students tend to drink bought water or water supplied by school. What may be the possible reason?

Author Response

 1) Line 39-41: The declined mortality may not be simply attributed to improved water quality. Actually, the availability of more vaccines is another important factor. Approximately 5.1 million child deaths in 1990 could be ascribed to vaccine-preventable diseases. From this point of view, the improved water quality may help to protect the children without vaccination. Please report more related data here and enrich the discussions.

The original intention was to emphasize that year 5 and under child mortality is still a looming challenge globally, and that diarrheal diseases are one factor among many that contribute to this. We have included additional references and made changes to the text to broaden the discussion more within the introduction and illustrate this point better (line 46-51, and 65-68).

 2) Line 164-165, “students were allowed to freely consume water from the GDM treatment system under the supervision of school staff.” Would the students drink the water directly or drink before boiling? Please add more details.

Water was consumed directly from the GDM system. More details in the materials and methods describing the GDM system design was added to include language indicating the filtration water tank acted as a point-of-use water drinking source.

 3) Line 217, Table 3: For the question of “Where does the water you drink at school come from?”, the answers were “Bottled, bought, supplied by school or Home”. Please describe the classifications in more details. For example, where did the bottled water come from? And what was the form of the “Bought” water? And what is the classification if the water supplied by school was in the Bottled form?

More details on characterizing the school water sources for consumption have been added to the manuscript (Line 158-162). We also have added more to the discussion and recognize that there may have been some confusion in the participants’ responses regarding this (Line 357-361).

 4) Line 217, Table 3: For the control group, the source of water supply also changed obviously. More students tend to drink bought water or water supplied by school. What may be the possible reason?

Private discussion from the schoolmasters at the control school site indicated they instructed students the tap water at the school was considered unsafe to drink. While there appears to be a large increase (10%) of students at the conclusion of the study that consumed water from the school source, overall (85%) students drank bottled water either that they bought, or was provided by the school. This is close to the overall percentage at the beginning of the study (78.1%) and we felt that this overall increase was not significant enough to highlight for additional discussion. In comparison, the roughly 76% increase of consumption of school supplied water for the GDM site was deemed to be substantial enough to bring up in the results and discussion sections (lines 209-210 and 361-363, respectively).

Round 2

Reviewer 1 Report

The paper has been revised.