Pub Date : 2023-11-14DOI: 10.1371/journal.pwat.0000201
Judith Glienke, Michael Stelter, Patrick Braeutigam
As the demand of freshwater increases with simultaneously aggravated climatic challenges, the development of efficient and effective water purification methods is of high importance. Qualitative Structure-Property Relationships (QSPRs) can support this process by calculating a correlation between the molecular structure and the degradability of water pollutants in a defined removal procedure, expressed by the kinetic constant of their removal. This can help to receive more mechanistical interpretation of the underlying process, but also to reduce experimental costs and time. As most QSPR models in wastewater treatment research are based on experimental data using ultrapure water as reaction solutions, it is still unknown to which extent QSPR models for different water matrices differ from each other with regard to selected descriptors and performance. Therefore, in this study the sonolytic degradation of 32 phenol derivates was investigated for three different water matrices (NaCl, Glucose, NaCl+Glucose) and compared to a previous study in ultrapure water. With only very few exceptions, the addition of water additives reduced the degradability of the target analytes. Based on these four datasets, QSPR modelling, respecting all five OECD principles for reliable QSPR models, were performed using numerous internal and external validations as well as statistical quality assurances to ensure good regression abilities as well as stability and predictivity. As the final four models were compared, it was observed that the descriptor selection and model calculation were highly impacted by the water additives. This was also confirmed when the descriptor pools of the best 10 models for each water composition were compared, as the descriptor pools were also highly dissimilar, indicating a shift in structural importance when changing the water composition. It could be shown that water matrices significantly influence the results of QSPR modelling even at very low concentrations of the matrix components.
{"title":"How do water matrices influence QSPR models in wastewater treatment?–A case study on the sonolytic elimination of phenol derivates","authors":"Judith Glienke, Michael Stelter, Patrick Braeutigam","doi":"10.1371/journal.pwat.0000201","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000201","url":null,"abstract":"As the demand of freshwater increases with simultaneously aggravated climatic challenges, the development of efficient and effective water purification methods is of high importance. Qualitative Structure-Property Relationships (QSPRs) can support this process by calculating a correlation between the molecular structure and the degradability of water pollutants in a defined removal procedure, expressed by the kinetic constant of their removal. This can help to receive more mechanistical interpretation of the underlying process, but also to reduce experimental costs and time. As most QSPR models in wastewater treatment research are based on experimental data using ultrapure water as reaction solutions, it is still unknown to which extent QSPR models for different water matrices differ from each other with regard to selected descriptors and performance. Therefore, in this study the sonolytic degradation of 32 phenol derivates was investigated for three different water matrices (NaCl, Glucose, NaCl+Glucose) and compared to a previous study in ultrapure water. With only very few exceptions, the addition of water additives reduced the degradability of the target analytes. Based on these four datasets, QSPR modelling, respecting all five OECD principles for reliable QSPR models, were performed using numerous internal and external validations as well as statistical quality assurances to ensure good regression abilities as well as stability and predictivity. As the final four models were compared, it was observed that the descriptor selection and model calculation were highly impacted by the water additives. This was also confirmed when the descriptor pools of the best 10 models for each water composition were compared, as the descriptor pools were also highly dissimilar, indicating a shift in structural importance when changing the water composition. It could be shown that water matrices significantly influence the results of QSPR modelling even at very low concentrations of the matrix components.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"16 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134991619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.1371/journal.pwat.0000129
Fabiana Almerinda G. Palma, Jonatas Fernandes Araújo Sodré, Nivison Nery, Luciana Joaquim Oliveira, Joe Brown, Anu Bourgeois, Claire A. Spears, Cassandra White, Federico Costa, Christine E. Stauber
Problems of access and quality of sanitary sewage disproportionately impact the health of populations in urban peripheries of low-and middle-income countries. The condominial sewer system is a practical, low-cost, effective, and simplified engineering approach compared to conventional sewer systems. In support of meeting the sanitation needs in highly populated urban settings, there is a need to understand the residents’ perceptions regarding the advantages and disadvantages of this sanitation model compared to conventional sewer systems. We conducted a cross-sectional study from September to December 2021 in two urban communities of Salvador, Bahia, Brazil, where condominial and conventional sewer systems had been implemented in the last five years. Of the 203 residents we interviewed, 50.7% lived in a site served by a condominial sewer system. Residents in the condominial sewer site reported not connecting to public sewage network (23.7% vs. 11.2%; p = 0.022) more often than in the conventional site. They reported more collective action to solve urban sanitation problems (69.9% vs. 54.0%; p = 0.020), such as manhole cleaning and unclogging efforts to fix plumbing. Despite these challenges, these residents expressed that the current service quality is better than it was in the previous two years. Our results suggest that even within urban periphery communities of a large Brazilian city, disparities exist in access to and quality of sanitation services that may be linked to sewage system implementation. Implementing simplified sewer systems is important to meet the growing sanitation demands of urban areas. However, these systems should also play a role in reducing sanitation disparities and the adoption of participatory approaches to meet the needs of populations in the most disadvantaged conditions. Despite challenging conditions, there is the potential for community engagement and active participation in sanitation-related matters, which could enhance the implementation and long-term sustainability of these systems.
卫生污水的获取和质量问题对低收入和中等收入国家城市边缘地区人口的健康产生了不成比例的影响。与传统的下水道系统相比，共用下水道系统是一种实用、低成本、有效和简化的工程方法。为了支持满足人口密集的城市环境中的卫生需求，需要了解居民对这种卫生模式与传统下水道系统相比的优缺点的看法。我们于2021年9月至12月在巴西巴伊亚州萨尔瓦多的两个城市社区进行了一项横断面研究，这些社区在过去五年中实施了共有和传统的下水道系统。在我们采访的203名居民中，50.7%的人居住在共用下水道系统的地方。合用下水道工地的居民报告没有连接到公共污水管网(23.7%对11.2%;P = 0.022)。他们报告了更多的集体行动来解决城市卫生问题(69.9% vs. 54.0%;P = 0.020)，例如检修孔的清洁和疏通管道的努力。尽管面临这些挑战，但这些居民表示，目前的服务质量比前两年要好。我们的研究结果表明，即使在巴西大城市的城市外围社区，卫生服务的获取和质量也存在差异，这可能与污水处理系统的实施有关。实施简化的下水道系统对于满足城市地区日益增长的卫生需求非常重要。但是，这些系统也应在减少卫生差距和采取参与性办法以满足处境最不利的人口的需要方面发挥作用。尽管条件具有挑战性，但社区参与和积极参与与卫生有关的事项是有潜力的，这可以加强这些系统的实施和长期可持续性。
{"title":"A tale of two communities: Comparing user perceptions of condominial and conventional sewer systems in Salvador, Brazil","authors":"Fabiana Almerinda G. Palma, Jonatas Fernandes Araújo Sodré, Nivison Nery, Luciana Joaquim Oliveira, Joe Brown, Anu Bourgeois, Claire A. Spears, Cassandra White, Federico Costa, Christine E. Stauber","doi":"10.1371/journal.pwat.0000129","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000129","url":null,"abstract":"Problems of access and quality of sanitary sewage disproportionately impact the health of populations in urban peripheries of low-and middle-income countries. The condominial sewer system is a practical, low-cost, effective, and simplified engineering approach compared to conventional sewer systems. In support of meeting the sanitation needs in highly populated urban settings, there is a need to understand the residents’ perceptions regarding the advantages and disadvantages of this sanitation model compared to conventional sewer systems. We conducted a cross-sectional study from September to December 2021 in two urban communities of Salvador, Bahia, Brazil, where condominial and conventional sewer systems had been implemented in the last five years. Of the 203 residents we interviewed, 50.7% lived in a site served by a condominial sewer system. Residents in the condominial sewer site reported not connecting to public sewage network (23.7% vs. 11.2%; p = 0.022) more often than in the conventional site. They reported more collective action to solve urban sanitation problems (69.9% vs. 54.0%; p = 0.020), such as manhole cleaning and unclogging efforts to fix plumbing. Despite these challenges, these residents expressed that the current service quality is better than it was in the previous two years. Our results suggest that even within urban periphery communities of a large Brazilian city, disparities exist in access to and quality of sanitation services that may be linked to sewage system implementation. Implementing simplified sewer systems is important to meet the growing sanitation demands of urban areas. However, these systems should also play a role in reducing sanitation disparities and the adoption of participatory approaches to meet the needs of populations in the most disadvantaged conditions. Despite challenging conditions, there is the potential for community engagement and active participation in sanitation-related matters, which could enhance the implementation and long-term sustainability of these systems.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"8 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135589494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-03DOI: 10.1371/journal.pwat.0000186
Naomi Francis, Becky Batagol, Allison P. Salinger, Litea Meo-Sewabu, Audra C. Bass, Sudirman Nasir, Daša Moschonas, Ruzka R. Taruc, Syaidah Syamsul, Hamdan Habsji, Autiko Tela, Isoa Vakarewa, Michaela F. Prescott, Isabel Charles, Idha Riu, Alexander Wilson, Mere Jane Sawailau, Losalini Malumu, Sheela S. Sinharoy
Globally, more than one billion people live in urban informal settlements and experience suboptimal access to safe water, sanitation and hygiene (WASH). Participatory approaches are increasingly being promoted in WASH interventions, but the key elements of these approaches are not well-defined. The Revitalising Informal Settlements and their Environments (RISE) program launched in 2017 uses a participatory approach to co-design water-sensitive infrastructure with residents of 24 urban informal settlements in Makassar, Indonesia and Suva, Fiji. Our objective was to identify key mechanisms of a gender and socially inclusive participatory approach for engaging diverse people in RISE. We conducted and analysed semi-structured in-depth interviews (IDIs) with 49 RISE program staff; IDIs with 29 residents from RISE settlements in Indonesia and Fiji; and 6 focus group discussions (FGDs) with RISE residents in Fiji in 2020–2021, after participatory design activities were complete. Resident participants were purposively selected for representation of women and men; high and low participation in RISE; and different levels of disability/impairment. The question guides were informed by the Consolidated Framework for Implementation Research (CFIR), which defines 39 constructs (grouped into five domains) that describe an intervention. The IDI and FGD transcripts were analysed thematically with deductive codes based on the CFIR. For each of the five CFIR domains, the construct that was most relevant to mechanisms for the engagement of diverse people was used for the final analysis. The findings identified several key mechanisms for engaging diverse residents in programs like RISE. Four of these are recommended for future implementation and scale-ups of RISE and similar programs: engaging with residents at the household level (and potentially the individual level); incorporating flexibility and adaptability throughout the program; having a diverse team; and maintaining regular contact and positive rapport between the staff and participants.
{"title":"Key mechanisms of a gender and socially inclusive community engagement and participatory design approach in the RISE program in Makassar, Indonesia and Suva, Fiji","authors":"Naomi Francis, Becky Batagol, Allison P. Salinger, Litea Meo-Sewabu, Audra C. Bass, Sudirman Nasir, Daša Moschonas, Ruzka R. Taruc, Syaidah Syamsul, Hamdan Habsji, Autiko Tela, Isoa Vakarewa, Michaela F. Prescott, Isabel Charles, Idha Riu, Alexander Wilson, Mere Jane Sawailau, Losalini Malumu, Sheela S. Sinharoy","doi":"10.1371/journal.pwat.0000186","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000186","url":null,"abstract":"Globally, more than one billion people live in urban informal settlements and experience suboptimal access to safe water, sanitation and hygiene (WASH). Participatory approaches are increasingly being promoted in WASH interventions, but the key elements of these approaches are not well-defined. The Revitalising Informal Settlements and their Environments (RISE) program launched in 2017 uses a participatory approach to co-design water-sensitive infrastructure with residents of 24 urban informal settlements in Makassar, Indonesia and Suva, Fiji. Our objective was to identify key mechanisms of a gender and socially inclusive participatory approach for engaging diverse people in RISE. We conducted and analysed semi-structured in-depth interviews (IDIs) with 49 RISE program staff; IDIs with 29 residents from RISE settlements in Indonesia and Fiji; and 6 focus group discussions (FGDs) with RISE residents in Fiji in 2020–2021, after participatory design activities were complete. Resident participants were purposively selected for representation of women and men; high and low participation in RISE; and different levels of disability/impairment. The question guides were informed by the Consolidated Framework for Implementation Research (CFIR), which defines 39 constructs (grouped into five domains) that describe an intervention. The IDI and FGD transcripts were analysed thematically with deductive codes based on the CFIR. For each of the five CFIR domains, the construct that was most relevant to mechanisms for the engagement of diverse people was used for the final analysis. The findings identified several key mechanisms for engaging diverse residents in programs like RISE. Four of these are recommended for future implementation and scale-ups of RISE and similar programs: engaging with residents at the household level (and potentially the individual level); incorporating flexibility and adaptability throughout the program; having a diverse team; and maintaining regular contact and positive rapport between the staff and participants.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"13 29","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135818621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.1371/journal.pwat.0000116
Pénélope Brueder, Alexandra Schleyer-Lindenmann, Corinne Curt, Franck Taillandier
In the context of intensification of flood risks, Nature Based Solutions constitute an interesting approach to conciliate population’s protection and biodiversity. While this recently emerging concept has been the subject of studies in social sciences, there is no work yet with a social representation approach. In this work, we propose to study Nature Based Solutions for flood risk management through the prism of social representations and how they frame the implementation of Nature Based Solutions projects in the field (obstacles and levers). We interviewed 19 flood experts who can be divided into two groups regarding Nature Based Solutions: theorists and practitioners. We studied their discourses using two types of analyses: a lexicometric analysis of the similarities and a thematic analysis. The results showed that Nature Based Solution is a social representation object in its complexity, the polarisation it creates and its technicality. The two groups of participants have different representations. The practitioners may consider the Nature Based Solutions as "greenwashing" since they are presented as new and innovative, while the theorists contrast their Nature Based Solutions’ vision with a "grey" vision influenced by French civil engineering culture and a need to control ecosystems. Both groups agree that Nature Based Solutions thinking is about "leaving more room for nature", which echoes Dunlap’s New Environmental Paradigm. Moreover, the results suggest that the expression “Nature Based Solutions” is not well suited to all actors. We encourage using the expression “vegetal engineering” which may provide an opportunity to reconnect with the techniques applied in the field. It also enhances the value of ancestral knowledge, which allows the general public to better connect with the concept.
{"title":"Nature based solutions for flood risks: What insights do the social representations of experts provide?","authors":"Pénélope Brueder, Alexandra Schleyer-Lindenmann, Corinne Curt, Franck Taillandier","doi":"10.1371/journal.pwat.0000116","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000116","url":null,"abstract":"In the context of intensification of flood risks, Nature Based Solutions constitute an interesting approach to conciliate population’s protection and biodiversity. While this recently emerging concept has been the subject of studies in social sciences, there is no work yet with a social representation approach. In this work, we propose to study Nature Based Solutions for flood risk management through the prism of social representations and how they frame the implementation of Nature Based Solutions projects in the field (obstacles and levers). We interviewed 19 flood experts who can be divided into two groups regarding Nature Based Solutions: theorists and practitioners. We studied their discourses using two types of analyses: a lexicometric analysis of the similarities and a thematic analysis. The results showed that Nature Based Solution is a social representation object in its complexity, the polarisation it creates and its technicality. The two groups of participants have different representations. The practitioners may consider the Nature Based Solutions as \"greenwashing\" since they are presented as new and innovative, while the theorists contrast their Nature Based Solutions’ vision with a \"grey\" vision influenced by French civil engineering culture and a need to control ecosystems. Both groups agree that Nature Based Solutions thinking is about \"leaving more room for nature\", which echoes Dunlap’s New Environmental Paradigm. Moreover, the results suggest that the expression “Nature Based Solutions” is not well suited to all actors. We encourage using the expression “vegetal engineering” which may provide an opportunity to reconnect with the techniques applied in the field. It also enhances the value of ancestral knowledge, which allows the general public to better connect with the concept.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"4 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135271644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-30DOI: 10.1371/journal.pwat.0000202
Abishek Sankara Narayan, Jennifer Davis
{"title":"Safe and sustainable water in cities","authors":"Abishek Sankara Narayan, Jennifer Davis","doi":"10.1371/journal.pwat.0000202","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000202","url":null,"abstract":"","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"225 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136102786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-27DOI: 10.1371/journal.pwat.0000177
Emma T. Brentjens, Elizabeth A. K. Beall, Robert M. Zucker
M . aeruginosa fluorescent changes were observed using a Cytek Aurora spectral flow cytometer that contains 5 lasers and 64 narrow band detectors located between 365 and 829 nm. Cyanobacteria were treated with different concentrations of H 2 O 2 and then monitored after exposure between 1 and 8 days. The red fluorescence emission derived from the excitation of cyanobacteria with a yellow green laser (550 nm) was measured in the 652–669 nm detector while green fluorescence from excitation with a violet laser (405 nm) was measured in the 532–550 nm detector. The changes in these parameters were measured after the addition of H 2 O 2 . There was an initial increase in red fluorescence intensity at 24 hours. This was followed by a daily decrease in red fluorescence intensity. In contrast, green fluorescence increased at 24 hours and remained higher than the control for the duration of the 8-day study. A similar fluorescence intensity effect as H 2 O 2 on M . aeruginosa fluorescence emissions was observed after exposure to acetylacetone, diuron (DCMU), peracetic acid, and tryptoline. Minimal growth was also observed in H 2 O 2 treated cyanobacteria during exposure of H 2 O 2 for 24 days. In another experiment, H 2 O 2 -treated cyanobacteria were exposed to high-intensity blue (14 mW) and UV (1 mW) lights to assess the effects of light stress on fluorescence emissions. The combination of blue and UV light with H 2 O 2 had a synergistic effect on M . aeruginosa that induced greater fluorescent differences between control and treated samples than exposure to either stimulus individually. These experiments suggest that the early increase in red and green fluorescence may be due to an inhibition in the ability of photosynthesis to process photons. Further research into the mechanisms driving these increases in fluorescence is necessary.
{"title":"Analysis of Microcystis aeruginosa physiology by spectral flow cytometry: Impact of chemical and light exposure","authors":"Emma T. Brentjens, Elizabeth A. K. Beall, Robert M. Zucker","doi":"10.1371/journal.pwat.0000177","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000177","url":null,"abstract":"M . aeruginosa fluorescent changes were observed using a Cytek Aurora spectral flow cytometer that contains 5 lasers and 64 narrow band detectors located between 365 and 829 nm. Cyanobacteria were treated with different concentrations of H 2 O 2 and then monitored after exposure between 1 and 8 days. The red fluorescence emission derived from the excitation of cyanobacteria with a yellow green laser (550 nm) was measured in the 652–669 nm detector while green fluorescence from excitation with a violet laser (405 nm) was measured in the 532–550 nm detector. The changes in these parameters were measured after the addition of H 2 O 2 . There was an initial increase in red fluorescence intensity at 24 hours. This was followed by a daily decrease in red fluorescence intensity. In contrast, green fluorescence increased at 24 hours and remained higher than the control for the duration of the 8-day study. A similar fluorescence intensity effect as H 2 O 2 on M . aeruginosa fluorescence emissions was observed after exposure to acetylacetone, diuron (DCMU), peracetic acid, and tryptoline. Minimal growth was also observed in H 2 O 2 treated cyanobacteria during exposure of H 2 O 2 for 24 days. In another experiment, H 2 O 2 -treated cyanobacteria were exposed to high-intensity blue (14 mW) and UV (1 mW) lights to assess the effects of light stress on fluorescence emissions. The combination of blue and UV light with H 2 O 2 had a synergistic effect on M . aeruginosa that induced greater fluorescent differences between control and treated samples than exposure to either stimulus individually. These experiments suggest that the early increase in red and green fluorescence may be due to an inhibition in the ability of photosynthesis to process photons. Further research into the mechanisms driving these increases in fluorescence is necessary.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"82 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136263271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-25DOI: 10.1371/journal.pwat.0000053
Jasmine Kelly, Mamonjisoa Tsilahatsy, Tolotra Carnot, Ramanantsiadiana Wilmin Fidelos, Giona Randriamanampy, Andrianarivelo Zafindrazana Charlier, Emilie Kowalczewski, Lomba Hasoavana, Mamy Andriatsihosena, Harry Chaplin, Hugo Legge
In settings where communities rely on unimproved water sources, household rainwater harvesting (HRWH) may improve the quality and quantity of water available. This research presents results from a two-year controlled before-and-after study that evaluated the impact of low-cost HRWH on household water collection habits, hygiene practices and prevalence of childhood diarrhoea in rural Madagascar. The study assessed system functionality, water quality and the acceptability of requesting household financial investment (16–20 USD). Surveys were administered to enrolled intervention households (n = 138) and control households (n = 276) at baseline and endline. Water quality tests at endline compared microbial contamination in a sub-sample of HRWH systems (n = 22) and public water sources (n = 8). Difference-in-difference analyses were used to compare changes in outcomes between study arms at baseline and endline. At endline 111 (75%) of systems were functional with an average age of 1.25 years. Microbial contamination was 39.3 TTC/100ml in community water sources compared with 23.3 TTC/100ml in the HRWH systems (coef: -16.0, 95CI: -37.3 to 5.2, p = 0.133). 85 (57%) of households completed their repayment plans while remaining households owed on average 3.7 USD. There was weak evidence to suggest that intervention households collected more water per capita day than controls (adj coefficient: 3.45; 95CI: -2.51 to 9.41, p = 0.257). Intervention households had 11% higher absolute risk of owning a handwashing station compared against controls (95CI: 0.00 to 0.23; p = 0.06). There was no evidence of differences in ownership of soap or prevalence of childhood diarrhoea between study arms. Overall, operation and maintenance of the systems remained high, users demonstrated willingness to pay, and there was weak evidence that water provision at the household increased domestic consumption. However, the systems did not provide contaminant-free water. We conclude that HRWH using low-cost, locally available materials can increase household access to water in areas reliant on limited communal water sources.
{"title":"Low-cost domestic rainwater harvesting in rural southeast Madagascar: A process and outcome evaluation","authors":"Jasmine Kelly, Mamonjisoa Tsilahatsy, Tolotra Carnot, Ramanantsiadiana Wilmin Fidelos, Giona Randriamanampy, Andrianarivelo Zafindrazana Charlier, Emilie Kowalczewski, Lomba Hasoavana, Mamy Andriatsihosena, Harry Chaplin, Hugo Legge","doi":"10.1371/journal.pwat.0000053","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000053","url":null,"abstract":"In settings where communities rely on unimproved water sources, household rainwater harvesting (HRWH) may improve the quality and quantity of water available. This research presents results from a two-year controlled before-and-after study that evaluated the impact of low-cost HRWH on household water collection habits, hygiene practices and prevalence of childhood diarrhoea in rural Madagascar. The study assessed system functionality, water quality and the acceptability of requesting household financial investment (16–20 USD). Surveys were administered to enrolled intervention households (n = 138) and control households (n = 276) at baseline and endline. Water quality tests at endline compared microbial contamination in a sub-sample of HRWH systems (n = 22) and public water sources (n = 8). Difference-in-difference analyses were used to compare changes in outcomes between study arms at baseline and endline. At endline 111 (75%) of systems were functional with an average age of 1.25 years. Microbial contamination was 39.3 TTC/100ml in community water sources compared with 23.3 TTC/100ml in the HRWH systems (coef: -16.0, 95CI: -37.3 to 5.2, p = 0.133). 85 (57%) of households completed their repayment plans while remaining households owed on average 3.7 USD. There was weak evidence to suggest that intervention households collected more water per capita day than controls (adj coefficient: 3.45; 95CI: -2.51 to 9.41, p = 0.257). Intervention households had 11% higher absolute risk of owning a handwashing station compared against controls (95CI: 0.00 to 0.23; p = 0.06). There was no evidence of differences in ownership of soap or prevalence of childhood diarrhoea between study arms. Overall, operation and maintenance of the systems remained high, users demonstrated willingness to pay, and there was weak evidence that water provision at the household increased domestic consumption. However, the systems did not provide contaminant-free water. We conclude that HRWH using low-cost, locally available materials can increase household access to water in areas reliant on limited communal water sources.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"27 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134974069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.1371/journal.pwat.0000171
Savanna K. Smith, Benjamin B. Risk, Rochelle H. Holm, Elizabeth Tilley, Petros Chigwechokha, Drew Capone, Joe Brown, Francis L. de los Reyes
Despite the widespread global reliance on pit latrines as improved sanitation systems, the decomposition of waste within pit latrines is poorly understood. One area needing elucidation is the characterization and function of microbial communities within pit latrines. To address this gap, we characterized the microbial communities of 55 lined pit latrines at three sampling layers from two communities in peri-urban Malawi. The microbial communities of the fecal sludge samples were analyzed for beta diversity, pathogen presence, and functional profiling. Household surveys were conducted and used to compare microbial community patterns to household characteristics and pit latrine use patterns. Compared to activated sludge, anaerobic digestion in municipal wastewater systems, and human gut microbiomes, pit latrines were found to contain unique microbial communities. While the microbial community composition as a whole did not vary by sampling depth, pathogen composition varied by sampling depth, location, and household water source. The inferred microbial function also varied by depth ( e . g ., increase in methanogens and decrease in aerobes with depth). The richness of lined pit latrines determined from surface samples from eight latrines was found to be representative for a given area. Samples from middle and lower depths collected using a Gulper pump did not provide more information on richness, a result that informs future sampling designs. These findings are important for improving waste-based epidemiology (WBE) approaches to understand community health and waste degradation characterization of lined pit latrines.
{"title":"Microbial community function and bacterial pathogen composition in pit latrines in peri-urban Malawi","authors":"Savanna K. Smith, Benjamin B. Risk, Rochelle H. Holm, Elizabeth Tilley, Petros Chigwechokha, Drew Capone, Joe Brown, Francis L. de los Reyes","doi":"10.1371/journal.pwat.0000171","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000171","url":null,"abstract":"Despite the widespread global reliance on pit latrines as improved sanitation systems, the decomposition of waste within pit latrines is poorly understood. One area needing elucidation is the characterization and function of microbial communities within pit latrines. To address this gap, we characterized the microbial communities of 55 lined pit latrines at three sampling layers from two communities in peri-urban Malawi. The microbial communities of the fecal sludge samples were analyzed for beta diversity, pathogen presence, and functional profiling. Household surveys were conducted and used to compare microbial community patterns to household characteristics and pit latrine use patterns. Compared to activated sludge, anaerobic digestion in municipal wastewater systems, and human gut microbiomes, pit latrines were found to contain unique microbial communities. While the microbial community composition as a whole did not vary by sampling depth, pathogen composition varied by sampling depth, location, and household water source. The inferred microbial function also varied by depth ( e . g ., increase in methanogens and decrease in aerobes with depth). The richness of lined pit latrines determined from surface samples from eight latrines was found to be representative for a given area. Samples from middle and lower depths collected using a Gulper pump did not provide more information on richness, a result that informs future sampling designs. These findings are important for improving waste-based epidemiology (WBE) approaches to understand community health and waste degradation characterization of lined pit latrines.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"875 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135887997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.1371/journal.pwat.0000140
Kelly Hoffman, David Holcomb, Stacie Reckling, Thomas Clerkin, Denene Blackwood, Rachelle Beattie, Francis de los Reyes, Angela Harris, Helena Mitasova, Nadine Kotlarz, Jill Stewart, Jacob Kazenelson, Lawrence Cahoon, Arthur Frampton, Mariya Munir, Allison Lee, Steven Berkowitz, Rachel Noble, Virginia T. Guidry, Lawrence Engel, Marc Serre, Ariel Christensen
Wastewater surveillance emerged during the COVID-19 pandemic as a novel strategy for tracking the burden of illness in communities. Previous work has shown that trends in wastewater SARS-CoV-2 viral loads correlate well with reported COVID-19 case trends over longer time periods (i.e., months). We used detrending time series to reveal shorter sub-trend patterns (i.e., weeks) to identify leads or lags in the temporal alignment of the wastewater/case relationship. Daily incident COVID-19 cases and twice-weekly wastewater SARS-CoV-2 viral loads measured at 20 North Carolina sewersheds in 2021 were detrended using smoothing ranges of ∞, 16, 8, 4 and 2 weeks, to produce detrended cases and wastewater viral loads at progressively finer time scales. For each sewershed and smoothing range, we calculated the Spearman correlation between the cases and the wastewater viral loads with offsets of -7 to +7 days. We identified a conclusive lead/lag relationship at 15 of 20 sewersheds, with detrended wastewater loads temporally leading detrended COVID-19 cases at 11 of these sites. For the 11 leading sites, the correlation between wastewater loads and cases was greatest for wastewater loads sampled at a median lead time of 6 days before the cases were reported. Distinct lead/lag relationships were the most pronounced after detrending with smoothing ranges of 4–8 weeks, suggesting that SARS-CoV-2 wastewater viral loads can track fluctuations in COVID-19 case incidence rates at fine time scales and may serve as a leading indicator in many settings. These results could help public health officials identify, and deploy timely responses in, areas where cases are increasing faster than the overall pandemic trend.
{"title":"Using detrending to assess SARS-CoV-2 wastewater loads as a leading indicator of fluctuations in COVID-19 cases at fine temporal scales: Correlations across twenty sewersheds in North Carolina","authors":"Kelly Hoffman, David Holcomb, Stacie Reckling, Thomas Clerkin, Denene Blackwood, Rachelle Beattie, Francis de los Reyes, Angela Harris, Helena Mitasova, Nadine Kotlarz, Jill Stewart, Jacob Kazenelson, Lawrence Cahoon, Arthur Frampton, Mariya Munir, Allison Lee, Steven Berkowitz, Rachel Noble, Virginia T. Guidry, Lawrence Engel, Marc Serre, Ariel Christensen","doi":"10.1371/journal.pwat.0000140","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000140","url":null,"abstract":"Wastewater surveillance emerged during the COVID-19 pandemic as a novel strategy for tracking the burden of illness in communities. Previous work has shown that trends in wastewater SARS-CoV-2 viral loads correlate well with reported COVID-19 case trends over longer time periods (i.e., months). We used detrending time series to reveal shorter sub-trend patterns (i.e., weeks) to identify leads or lags in the temporal alignment of the wastewater/case relationship. Daily incident COVID-19 cases and twice-weekly wastewater SARS-CoV-2 viral loads measured at 20 North Carolina sewersheds in 2021 were detrended using smoothing ranges of ∞, 16, 8, 4 and 2 weeks, to produce detrended cases and wastewater viral loads at progressively finer time scales. For each sewershed and smoothing range, we calculated the Spearman correlation between the cases and the wastewater viral loads with offsets of -7 to +7 days. We identified a conclusive lead/lag relationship at 15 of 20 sewersheds, with detrended wastewater loads temporally leading detrended COVID-19 cases at 11 of these sites. For the 11 leading sites, the correlation between wastewater loads and cases was greatest for wastewater loads sampled at a median lead time of 6 days before the cases were reported. Distinct lead/lag relationships were the most pronounced after detrending with smoothing ranges of 4–8 weeks, suggesting that SARS-CoV-2 wastewater viral loads can track fluctuations in COVID-19 case incidence rates at fine time scales and may serve as a leading indicator in many settings. These results could help public health officials identify, and deploy timely responses in, areas where cases are increasing faster than the overall pandemic trend.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135887996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study aims to investigate the impact of anthropogenic influences within the catchment areas on the sediment physico-chemical quality of Owalla Reservoir in Osun State, Nigeria with the primary aim of creating baseline information on the aspect of limnology. Twenty sampling stations were established along the reservoir representing, its three different sections and two zones. The sampling was conducted for a period of two years to cover both seasons of the year in the area. The sediment samples were collected using a Van-Veen grab of 0.04 m 2 area (0.2m × 0.2m) from the waterbed at each sampling locations; labelled, kept in cooler at 4°C and transported to the laboratory for the analysis. The reservoir sediment was mainly clayey-sand in texture, while the particle size distribution was in this order: sand (73.1%) > clay (17.4%) > silt (9.4%). The exchangeable cations order of dominance was in this order: Mg 2+ > Ca 2+ > H + > Al 3+ > K + >Na + and anions in this order: PO 3 4 - > SO 4 2- > NO 3 - > Cl - . The highest mean values for water depth, transparency, air temperature, water temperature and sediment temperature (5.28 ± 0.40 m, 1.60 ± 0.05 m, 31.90 ± 0.29°C, 30.6 ± 0.18°C and 27.6 ± 0.23°C) were recorded during the dry season compared with the rainy season. The results obtained from this study, shows that Owalla Reservoir is fairly clean and not contaminated with toxic pollutants. The sediment pH is within acidic range, and enriched with nutrients due to the anthropogenic activities around this reservoir catchment areas. However, if the organic enrichments and siltation in this reservoir is not controlled, it could lead to the future eutrophication of this waterbody, which can cause water quality degradation, alter the aquatic biota and natural ageing process of this reservoir making it unsuitable for its purposes.
{"title":"Assessing the impact of anthropogenic influences on the sediment quality of Owalla Reservoir, Southwest, Nigeria","authors":"Adedeji Idowu Aduwo, Taiwo Adekanmi Adesakin, Abayomi Tolulope Oyewale, Israel Funso Adeniyi","doi":"10.1371/journal.pwat.0000135","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000135","url":null,"abstract":"The study aims to investigate the impact of anthropogenic influences within the catchment areas on the sediment physico-chemical quality of Owalla Reservoir in Osun State, Nigeria with the primary aim of creating baseline information on the aspect of limnology. Twenty sampling stations were established along the reservoir representing, its three different sections and two zones. The sampling was conducted for a period of two years to cover both seasons of the year in the area. The sediment samples were collected using a Van-Veen grab of 0.04 m 2 area (0.2m × 0.2m) from the waterbed at each sampling locations; labelled, kept in cooler at 4°C and transported to the laboratory for the analysis. The reservoir sediment was mainly clayey-sand in texture, while the particle size distribution was in this order: sand (73.1%) > clay (17.4%) > silt (9.4%). The exchangeable cations order of dominance was in this order: Mg 2+ > Ca 2+ > H + > Al 3+ > K + >Na + and anions in this order: PO 3 4 - > SO 4 2- > NO 3 - > Cl - . The highest mean values for water depth, transparency, air temperature, water temperature and sediment temperature (5.28 ± 0.40 m, 1.60 ± 0.05 m, 31.90 ± 0.29°C, 30.6 ± 0.18°C and 27.6 ± 0.23°C) were recorded during the dry season compared with the rainy season. The results obtained from this study, shows that Owalla Reservoir is fairly clean and not contaminated with toxic pollutants. The sediment pH is within acidic range, and enriched with nutrients due to the anthropogenic activities around this reservoir catchment areas. However, if the organic enrichments and siltation in this reservoir is not controlled, it could lead to the future eutrophication of this waterbody, which can cause water quality degradation, alter the aquatic biota and natural ageing process of this reservoir making it unsuitable for its purposes.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"249 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136098107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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