This study presents a novel framework for estimating safe swimming distances at beaches and is th... more This study presents a novel framework for estimating safe swimming distances at beaches and is the first participatory environmental science study to experimentally test strategies for increasing volunteer retention.
Container-based sanitation (CBS) – in which wastes are captured in sealable containers that are t... more Container-based sanitation (CBS) – in which wastes are captured in sealable containers that are then transported to treatment facilities – is an alternative sanitation option in urban areas where on-site sanitation and sewerage are infeasible. This paper presents the results of a pilot household CBS service in Cap Haitien, Haiti. We quantify the excreta generated weekly in a dense urban slum,(1) the proportion safely removed via container-based public and household toilets, and the costs associated with these systems. The CBS service yielded an approximately 3.5-fold decrease in the unmanaged share of faeces produced, and nearly eliminated the reported use of open defecation and “flying toilets” among service recipients. The costs of this pilot small-scale service were higher than those of large-scale waterborne sewerage, but economies of scale have the potential to reduce CBS costs over time. The paper concludes with a discussion of planning and policy implications of incorporating...
This paper reports the main findings of a multi-country research project designed to develop a be... more This paper reports the main findings of a multi-country research project designed to develop a better understanding of the performance of community-managed rural water supply systems in developing countries. Data were collected from households, village water committees, focus groups of village residents, system operators and key informants in 400 rural communities in Peru, Bolivia and Ghana. Our findings suggest that the demand-driven, community management model, coupled with access to spare parts and some technical expertise, has come a long way toward unraveling the puzzle of how best to design and implement rural water supply programs in developing countries. In all three countries, rural water supply projects were working. Among the households included in our sample in Peru and Bolivia, 95% had operational taps at the time of our field visit. In 90% of the villages in Ghana, all project handpumps were still working. Not only had the rural water systems not broken down, but almos...
Communal anaerobic digesters (ADs) have been promoted as a waste-to-energy strategy that can prov... more Communal anaerobic digesters (ADs) have been promoted as a waste-to-energy strategy that can provide sanitation and clean energy co-benefits. However, little empirical evidence is available regarding the performance of such systems in field conditions. This study assesses the wastewater treatment efficiency, energy production, greenhouse gas (GHG) emissions, and financial costs and benefits of communal ADs used for domestic wastewater treatment in Zambia. Primary data on the technical performance of 15 ADs were collected over a 6-month period and in-person interviews were conducted with heads of 120 households. Findings from this study suggest that ADs offer comparable wastewater treatment efficiencies and greater GHG emission reduction benefits relative to conventional septic tanks (STs), with the greatest benefits in settings with reliable access to water, use of low efficiency solid fuels and with sufficient demand for biogas in proximity to supply. However, absent a mechanism to...
Journal of Water, Sanitation and Hygiene for Development, 2014
The excreta of more than half of the world's population is discharged into the environment wi... more The excreta of more than half of the world's population is discharged into the environment without treatment of any kind. Particularly in low- and middle-income countries with limited public finance for treatment infrastructure, resource recovery from wastewater has the potential to finance part of the costs of sanitation systems. Most assessments of resource-recovering treatment systems in low-income settings have focused on their technical performance. In this study, using data collected from 14 upward-flow anaerobic sludge blanket septic tanks in rural Panama, we estimate the proportion of waste treatment system costs that could be offset by biogas sales. We find that biogas revenues would cover between 26% and 49% of system operation and maintenance expenses, and would improve the net present value of the wastewater system investment by 8% to 15%. Aggregate stated demand for in-home biogas delivery among sample households is more than twice the volume of gas that could be ge...
A new water supply and sanitation planning approach is now becoming accepted in many developing c... more A new water supply and sanitation planning approach is now becoming accepted in many developing countries. This new approach holds that investment in the water and sanitation sector should be demand driven, ie, that households should be provided with services they want and for ...
Support is growing for the incorporation of fetching time and/or distance considerations in the d... more Support is growing for the incorporation of fetching time and/or distance considerations in the definition of access to improved water supply used for global monitoring. Current efforts typically rely on self-reported distance and/or travel time data that have been shown to be unreliable. To date, however, there has been no head-to-head comparison of such indicators with other possible distance/time metrics. This study provides such a comparison. We examine the association between both straight-line distance and self-reported one-way travel time with measured route distances to water sources for 1,103 households in Nampula province, Mozambique. We find straight-line, or Euclidean, distance to be a good proxy for route distance (R2 = 0.98), while self-reported travel time is a poor proxy (R2 = 0.12). We also apply a variety of time- and distance-based indicators proposed in the literature to our sample data, finding that the share of households classified as having versus lacking acc...
In sub-Saharan Africa only 35% of the urban population has access to a piped water connection on ... more In sub-Saharan Africa only 35% of the urban population has access to a piped water connection on their premises. The majority of households obtain water from public standpipes or from neighbors who are connected to the municipal network. Water resale is often prohibited, however, because of concerns about affordability and risks to public health. Using data collected from 1,377 households in Maputo, Mozambique, we compare the microbiological quality, as well as the time and money costs of water supply from individual house connections, public standpipes, and water obtained from neighbors. Households with their own water connections have better service across virtually all indicators measured, and express greater satisfaction with their service, as compared with those using other water sources. Households purchasing water from their neighbors pay lower time and money costs per liter of water, on average, as compared with those using standpipes. Resale competes favorably with standpip...
Little is known about the extent or pattern of environmental fecal contamination among households... more Little is known about the extent or pattern of environmental fecal contamination among households using low-cost, on-site sanitation facilities, or what role environmental contamination plays in the transmission of diarrheal disease. A microbial survey of fecal contamination and selected diarrheal pathogens in soil (n = 200), surface (n = 120), and produce samples (n = 24) was conducted in peri-urban Bagamoyo, Tanzania, among 20 households using private pit latrines. All samples were analyzed for E. coli and enterococci. A subset was analyzed for enterovirus, rotavirus, norovirus GI, norovirus GII, diarrheagenic E. coli, and general and human-specific Bacteroidales fecal markers using molecular methods. Soil collected from the house floor had significantly higher concentrations of E. coli and enterococci than soil collected from the latrine floor. There was no significant difference in fecal indicator bacteria levels between households using pit latrines with a concrete slab (improved sanitation) versus those without a slab. These findings imply that the presence of a concrete slab does not affect the level of fecal contamination in the household environment in this setting. Human Bacteroidales, pathogenic E. coli, enterovirus, and rotavirus genes were detected in soil samples, suggesting that soil should be given more attention as a transmission pathway of diarrheal illness in low-income countries.
ABSTRACT Despite substantial programmatic investment in domestic bio-digesters across sub-Saharan... more ABSTRACT Despite substantial programmatic investment in domestic bio-digesters across sub-Saharan Africa in recent years, little empirical evidence has been published regarding the existence or magnitude of socioeconomic or environmental benefits accruing from bio-digester implementation. A cross-sectional study of 40 households in Arusha, Tanzania, suggests that bio-digester adoption has the potential to reduce fuel-wood use, energy-related expenditures, and time-costs of energy procurement; to lower CO2e emissions; and to increase farm incomes. No significant differences in synthetic fertilizer use were observed between households with and without bio-digesters. Domestic bio-digester investments were found to have a positive net present value across a wide range of discount rates. Further, we estimate that domestic bio-digester implementation at the country wide level in Tanzania could potentially access $80–$115 million annually in carbon emissions reduction (CER) financing through the Clean Development Mechanism.
This study presents a novel framework for estimating safe swimming distances at beaches and is th... more This study presents a novel framework for estimating safe swimming distances at beaches and is the first participatory environmental science study to experimentally test strategies for increasing volunteer retention.
Container-based sanitation (CBS) – in which wastes are captured in sealable containers that are t... more Container-based sanitation (CBS) – in which wastes are captured in sealable containers that are then transported to treatment facilities – is an alternative sanitation option in urban areas where on-site sanitation and sewerage are infeasible. This paper presents the results of a pilot household CBS service in Cap Haitien, Haiti. We quantify the excreta generated weekly in a dense urban slum,(1) the proportion safely removed via container-based public and household toilets, and the costs associated with these systems. The CBS service yielded an approximately 3.5-fold decrease in the unmanaged share of faeces produced, and nearly eliminated the reported use of open defecation and “flying toilets” among service recipients. The costs of this pilot small-scale service were higher than those of large-scale waterborne sewerage, but economies of scale have the potential to reduce CBS costs over time. The paper concludes with a discussion of planning and policy implications of incorporating...
This paper reports the main findings of a multi-country research project designed to develop a be... more This paper reports the main findings of a multi-country research project designed to develop a better understanding of the performance of community-managed rural water supply systems in developing countries. Data were collected from households, village water committees, focus groups of village residents, system operators and key informants in 400 rural communities in Peru, Bolivia and Ghana. Our findings suggest that the demand-driven, community management model, coupled with access to spare parts and some technical expertise, has come a long way toward unraveling the puzzle of how best to design and implement rural water supply programs in developing countries. In all three countries, rural water supply projects were working. Among the households included in our sample in Peru and Bolivia, 95% had operational taps at the time of our field visit. In 90% of the villages in Ghana, all project handpumps were still working. Not only had the rural water systems not broken down, but almos...
Communal anaerobic digesters (ADs) have been promoted as a waste-to-energy strategy that can prov... more Communal anaerobic digesters (ADs) have been promoted as a waste-to-energy strategy that can provide sanitation and clean energy co-benefits. However, little empirical evidence is available regarding the performance of such systems in field conditions. This study assesses the wastewater treatment efficiency, energy production, greenhouse gas (GHG) emissions, and financial costs and benefits of communal ADs used for domestic wastewater treatment in Zambia. Primary data on the technical performance of 15 ADs were collected over a 6-month period and in-person interviews were conducted with heads of 120 households. Findings from this study suggest that ADs offer comparable wastewater treatment efficiencies and greater GHG emission reduction benefits relative to conventional septic tanks (STs), with the greatest benefits in settings with reliable access to water, use of low efficiency solid fuels and with sufficient demand for biogas in proximity to supply. However, absent a mechanism to...
Journal of Water, Sanitation and Hygiene for Development, 2014
The excreta of more than half of the world's population is discharged into the environment wi... more The excreta of more than half of the world's population is discharged into the environment without treatment of any kind. Particularly in low- and middle-income countries with limited public finance for treatment infrastructure, resource recovery from wastewater has the potential to finance part of the costs of sanitation systems. Most assessments of resource-recovering treatment systems in low-income settings have focused on their technical performance. In this study, using data collected from 14 upward-flow anaerobic sludge blanket septic tanks in rural Panama, we estimate the proportion of waste treatment system costs that could be offset by biogas sales. We find that biogas revenues would cover between 26% and 49% of system operation and maintenance expenses, and would improve the net present value of the wastewater system investment by 8% to 15%. Aggregate stated demand for in-home biogas delivery among sample households is more than twice the volume of gas that could be ge...
A new water supply and sanitation planning approach is now becoming accepted in many developing c... more A new water supply and sanitation planning approach is now becoming accepted in many developing countries. This new approach holds that investment in the water and sanitation sector should be demand driven, ie, that households should be provided with services they want and for ...
Support is growing for the incorporation of fetching time and/or distance considerations in the d... more Support is growing for the incorporation of fetching time and/or distance considerations in the definition of access to improved water supply used for global monitoring. Current efforts typically rely on self-reported distance and/or travel time data that have been shown to be unreliable. To date, however, there has been no head-to-head comparison of such indicators with other possible distance/time metrics. This study provides such a comparison. We examine the association between both straight-line distance and self-reported one-way travel time with measured route distances to water sources for 1,103 households in Nampula province, Mozambique. We find straight-line, or Euclidean, distance to be a good proxy for route distance (R2 = 0.98), while self-reported travel time is a poor proxy (R2 = 0.12). We also apply a variety of time- and distance-based indicators proposed in the literature to our sample data, finding that the share of households classified as having versus lacking acc...
In sub-Saharan Africa only 35% of the urban population has access to a piped water connection on ... more In sub-Saharan Africa only 35% of the urban population has access to a piped water connection on their premises. The majority of households obtain water from public standpipes or from neighbors who are connected to the municipal network. Water resale is often prohibited, however, because of concerns about affordability and risks to public health. Using data collected from 1,377 households in Maputo, Mozambique, we compare the microbiological quality, as well as the time and money costs of water supply from individual house connections, public standpipes, and water obtained from neighbors. Households with their own water connections have better service across virtually all indicators measured, and express greater satisfaction with their service, as compared with those using other water sources. Households purchasing water from their neighbors pay lower time and money costs per liter of water, on average, as compared with those using standpipes. Resale competes favorably with standpip...
Little is known about the extent or pattern of environmental fecal contamination among households... more Little is known about the extent or pattern of environmental fecal contamination among households using low-cost, on-site sanitation facilities, or what role environmental contamination plays in the transmission of diarrheal disease. A microbial survey of fecal contamination and selected diarrheal pathogens in soil (n = 200), surface (n = 120), and produce samples (n = 24) was conducted in peri-urban Bagamoyo, Tanzania, among 20 households using private pit latrines. All samples were analyzed for E. coli and enterococci. A subset was analyzed for enterovirus, rotavirus, norovirus GI, norovirus GII, diarrheagenic E. coli, and general and human-specific Bacteroidales fecal markers using molecular methods. Soil collected from the house floor had significantly higher concentrations of E. coli and enterococci than soil collected from the latrine floor. There was no significant difference in fecal indicator bacteria levels between households using pit latrines with a concrete slab (improved sanitation) versus those without a slab. These findings imply that the presence of a concrete slab does not affect the level of fecal contamination in the household environment in this setting. Human Bacteroidales, pathogenic E. coli, enterovirus, and rotavirus genes were detected in soil samples, suggesting that soil should be given more attention as a transmission pathway of diarrheal illness in low-income countries.
ABSTRACT Despite substantial programmatic investment in domestic bio-digesters across sub-Saharan... more ABSTRACT Despite substantial programmatic investment in domestic bio-digesters across sub-Saharan Africa in recent years, little empirical evidence has been published regarding the existence or magnitude of socioeconomic or environmental benefits accruing from bio-digester implementation. A cross-sectional study of 40 households in Arusha, Tanzania, suggests that bio-digester adoption has the potential to reduce fuel-wood use, energy-related expenditures, and time-costs of energy procurement; to lower CO2e emissions; and to increase farm incomes. No significant differences in synthetic fertilizer use were observed between households with and without bio-digesters. Domestic bio-digester investments were found to have a positive net present value across a wide range of discount rates. Further, we estimate that domestic bio-digester implementation at the country wide level in Tanzania could potentially access $80–$115 million annually in carbon emissions reduction (CER) financing through the Clean Development Mechanism.
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Papers by Jenna Davis