Centralized or Onsite Testing? Examining the Costs of Water Quality Monitoring in Rural Africa.

Rural water systems in Africa have room to improve water quality monitoring. However, the most cost-effective approach for microbial water testing remains uncertain. This study compared the cost per E. coli test (membrane filtration) of four approaches representing different levels of centralization: (i) one centralized laboratory serving all water systems, (ii) a mobile laboratory serving all systems, (iii) multiple semi-centralized laboratories serving clusters of systems, and (iv) decentralized analysis at each system. We employed Monte Carlo analyses to model the costs of these approaches in three real-world contexts in Ghana and Uganda and in hypothetical simulations capturing various conditions across rural Africa. Centralized testing was the lowest cost in two real-world settings and the widest variety of simulations, especially those with water systems close to a central laboratory (<36 km). Semi-centralized testing was the lowest cost in one real-world setting and in simulations with clustered water systems and intermediate sampling frequencies (1-2 monthly samples per system). The mobile lab was the lowest cost in the fewest simulations, requiring few systems and infrequent sampling. Decentralized testing was cost-effective for remote systems and frequent sampling, but only if sampling did not require a dedicated vehicle. Alternative low-cost testing methods could make decentralized testing more competitive.

Where Does CLTS Work Best? Quantifying Predictors of CLTS Performance in Four Countries.

Improving the effectiveness of rural sanitation interventions is critical for meeting the United Nations' Sustainable Development Goals and improving public health. Community-led total sanitation (CLTS) is the most widely used rural sanitation intervention globally; however, evidence shows that CLTS does not work equally well everywhere. Contextual factors outside the control of implementers may partially determine CLTS outcomes, although the extent of these influences is poorly understood. In this study, we investigate the extent to which 18 contextual factors from readily available datasets can help predict the achievement and sustainability of open-defecation-free (ODF) status in Cambodia, Ghana, Liberia, and Zambia. Using multilevel logistic regressions, we found that the predictors of CLTS performance varied between countries, with the exception of small community size. Accessibility and literacy levels were correlated with CLTS outcomes, but the direction of correlation differed between countries. To translate findings into practical guidance for CLTS implementers, we used classification and regression trees to identify a "split point" for each contextual factor significantly associated with ODF achievement. We also identified the combinations of factors conducive to a minimum of 50% ODF achievement. This study demonstrates that publicly available, high-resolution datasets on accessibility, socioeconomic, and environmental factors can be leveraged to target CLTS activities to the most favorable contexts.

How Much Will Safe Sanitation for all Cost? Evidence from Five Cities.

Global sustainable development goals call for universal access to safely managed sanitation by 2030. Here, we demonstrate methods to estimate the financial requirements for meeting this commitment in urban settings of low-income countries. Our methods considered two financial requirements: (i) the subsidies needed to bridge the gap between the willingness-to-pay of low-income households and actual market prices of toilets and emptying services and (ii) the amounts needed to expand the municipal waste management infrastructure for unserved populations. We applied our methods in five cities- Kisumu, Malindi, Nakuru in Kenya; Kumasi in Ghana; and Rangpur in Bangladesh and compared three to five sanitation approaches in each city. We collected detailed cost data on the sanitation infrastructure, products, and services from 76 key informants across the five cities, and we surveyed a total of 2381 low-income households to estimate willingness-to-pay. We found that the total financial requirements for achieving universal sanitation in the next 10 years and their breakdown between household subsidies and municipal infrastructure varied greatly between sanitation approaches. Across our study cities, sewerage was the costliest approach (total financial requirements of 16-24 USD/person/year), followed by container-based sanitation (10-17 USD/person/year), onsite sanitation (2-14 USD/person/year), and mini-sewers connecting several toilets to communal septic tanks (3-5 USD/person/year). Further applications of our methods can guide sanitation planning in other cities.

What Environmental Factors Influence the Concentration of Fecal Indicator Bacteria in Groundwater? Insights from Explanatory Modeling in Uganda and Bangladesh.

Information about microbial water quality is critical for managing water safety and protecting public health. In low-income countries, monitoring all drinking water supplies is impractical because financial resources and capacity are insufficient. Data sets derived from satellite imagery, census, and hydrological models provide an opportunity to examine relationships between a suite of environmental risk factors and microbial water quality over large geographical scales. We investigated the relationships between groundwater fecal contamination and different environmental parameters in Uganda and Bangladesh. In Uganda, groundwater contamination was associated with high population density (p < 0.001; OR = 1.27), high cropland coverage (p < 0.001; OR = 1.47), high average monthly precipitation (p < 0.001; OR = 1.14), and high surface runoff (p < 0.001; OR = 1.37), while low groundwater contamination was more likely in areas further from cities (p < 0.001; OR = 0.66) and with higher forest coverage (p < 0.001; OR = 0.70). In Bangladesh, contamination was associated with higher weekly precipitation (p < 0.001; OR = 1.44) and higher livestock density (p = 0.05; OR = 1.11), while low contamination was associated with low forest coverage (p < 0.001; OR = 1.23) and high cropland coverage (p < 0.001; OR = 0.80). We developed a groundwater contamination index for each country to help decision-makers identify areas where groundwater is most prone to fecal contamination and prioritize monitoring activities. Our approach demonstrates how to harness satellite-derived data to guide water safety management.

The effect of sodium thiosulfate dechlorination on fecal indicator bacteria enumeration: laboratory and field data.

In microbiological water quality testing, sample dechlorination with sodium thiosulfate is recommended to ensure that results accurately reflect the water quality at sample collection. Nevertheless, monitoring institutions in low-resource settings do not always dechlorinate samples, and there is limited research describing how this practice impacts drinking water quality results. The effect of dechlorination on indicator bacteria counts was evaluated by spiking laboratory water with five Escherichia coli (E. coli) concentrations (104-108 CFU/100 mL), chlorinating at six doses (0-0.6 mg/L), holding samples with and without sodium thiosulfate for 5-7 hours, and enumerating E. coli by membrane filtration with m-lauryl sulfate media. Additionally, sub-Saharan African water suppliers enumerated thermotolerant coliform by membrane filtration in paired chlorinated water samples collected with and without sodium thiosulfate. Across all E. coli and chlorine doses in the laboratory, and all field tests, samples held without sodium thiosulfate had lower bacteria counts (p < 0.001). Additionally, chlorinated water supply samples held without sodium thiosulfate had an 87.5% false negative rate. Results indicate the importance of dechlorinating microbiological water quality samples, discarding data from chlorinated samples collected without dechlorination, and reinforcing dechlorination recommendations in resource-limited environments to improve water safety management.

How Much Will It Cost To Monitor Microbial Drinking Water Quality in Sub-Saharan Africa?

Microbial water quality monitoring is crucial for managing water resources and protecting public health. However, institutional testing activities in sub-Saharan Africa are currently limited. Because the economics of water quality testing are poorly understood, the extent to which cost may be a barrier to monitoring in different settings is unclear. This study used cost data from 18 African monitoring institutions (piped water suppliers and health surveillance agencies in six countries) and estimates of water supply type coverage from 15 countries to assess the annual financial requirements for microbial water testing at both national and regional levels, using World Health Organization recommendations for sampling frequency. We found that a microbial water quality test costs 21.0 ± 11.3 USD, on average, including consumables, equipment, labor, and logistics, which is higher than previously calculated. Our annual cost estimates for microbial monitoring of piped supplies and improved point sources ranged between 8 000 USD for Equatorial Guinea and 1.9 million USD for Ethiopia, depending primarily on the population served but also on the distribution of piped water system sizes. A comparison with current national water and sanitation budgets showed that the cost of implementing prescribed testing levels represents a relatively modest proportion of existing budgets (<2%). At the regional level, we estimated that monitoring the microbial quality of all improved water sources in sub-Saharan Africa would cost 16.0 million USD per year, which is minimal in comparison to the projected annual capital costs of achieving Sustainable Development Goal 6.1 of safe water for all (14.8 billion USD).

Supply and Demand for Improved Sanitation: Results from Randomized Pricing Experiments in Rural Tanzania.

Improving access to sanitation is a global public health priority. Sufficient consumer demand is required for sanitation coverage to expand through private provision. To measure consumer demand for hygienic latrine platform products in rural Tanzania, we conducted a randomized, voucher-based real-money sales trial with 1638 households with unimproved latrines. We also evaluated multiple supply chain options to determine the costs of supplying latrine platform products to rural households. For concrete latrine SanPlats, 60% of households were willing to pay US$0.48 and 10% of households were willing to pay US$4.05, yet the average cost of supplying the SanPlat to households was US$7.51. Similarly, for plastic sanitary platforms, willingness-to-pay (WTP) dropped from almost 60% at a price of US$1.43 to 5% at a price of US$12.29, compared to an average supply cost of US$23.28. WTP was not significantly different between villages that had participated in the National Sanitation Campaign and those that had not. Randomized informational interventions, including hygiene data-sharing and peer-based exposure to latrine platform products, had minimal effects on WTP. In conclusion, current household demand for latrine platform products is too low to achieve national goals for improved sanitation coverage through fully commercial distribution.

Assessing Drinking Water Quality and Water Safety Management in Sub-Saharan Africa Using Regulated Monitoring Data.

Universal access to safe drinking water is prioritized in the post-2015 Sustainable Development Goals. Collecting reliable and actionable water quality information in low-resource settings, however, is challenging, and little is known about the correspondence between water quality data collected by local monitoring agencies and global frameworks for water safety. Using 42 926 microbial water quality test results from 32 surveillance agencies and water suppliers in seven sub-Saharan African countries, we determined the degree to which water sources were monitored, how water quality varied by source type, and institutional responses to results. Sixty-four percent of the water samples were collected from piped supplies, although the majority of Africans rely on nonpiped sources. Piped supplies had the lowest levels of fecal indicator bacteria (FIB) compared to any other source type: only 4% of samples of water piped to plots and 2% of samples from water piped to public taps/standpipes were positive for FIB (n = 14 948 and n = 12 278, respectively). Among other types of improved sources, samples from harvested rainwater and boreholes were less often positive for FIB (22%, n = 167 and 31%, n = 3329, respectively) than protected springs or protected dug wells (39%, n = 472 and 65%, n = 505). When data from different settings were aggregated, the FIB levels in different source types broadly reflected the source-type water safety framework used by the Joint Monitoring Programme. However, the insufficient testing of nonpiped sources relative to their use indicates important gaps in current assessments. Our results emphasize the importance of local data collection for water safety management and measurement of progress toward universal safe drinking water access.

Interventions to improve water quality for preventing diarrhoea.

BACKGROUND: Diarrhoea is a major cause of death and disease, especially among young children in low-income countries. In these settings, many infectious agents associated with diarrhoea are spread through water contaminated with faeces.In remote and low-income settings, source-based water quality improvement includes providing protected groundwater (springs, wells, and bore holes), or harvested rainwater as an alternative to surface sources (rivers and lakes). Point-of-use water quality improvement interventions include boiling, chlorination, flocculation, filtration, or solar disinfection, mainly conducted at home. OBJECTIVES: To assess the effectiveness of interventions to improve water quality for preventing diarrhoea. SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register (11 November 2014), CENTRAL (the Cochrane Library, 7 November 2014), MEDLINE (1966 to 10 November 2014), EMBASE (1974 to 10 November 2014), and LILACS (1982 to 7 November 2014). We also handsearched relevant conference proceedings, contacted researchers and organizations working in the field, and checked references from identified studies through 11 November 2014. SELECTION CRITERIA: Randomized controlled trials (RCTs), quasi-RCTs, and controlled before-and-after studies (CBA) comparing interventions aimed at improving the microbiological quality of drinking water with no intervention in children and adults. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. We used meta-analyses to estimate pooled measures of effect, where appropriate, and investigated potential sources of heterogeneity using subgroup analyses. We assessed the quality of evidence using the GRADE approach. MAIN RESULTS: Forty-five cluster-RCTs, two quasi-RCTs, and eight CBA studies, including over 84,000 participants, met the inclusion criteria. Most included studies were conducted in low- or middle-income countries (LMICs) (50 studies) with unimproved water sources (30 studies) and unimproved or unclear sanitation (34 studies). The primary outcome in most studies was self-reported diarrhoea, which is at high risk of bias due to the lack of blinding in over 80% of the included studies. Source-based water quality improvementsThere is currently insufficient evidence to know if source-based improvements such as protected wells, communal tap stands, or chlorination/filtration of community sources consistently reduce diarrhoea (one cluster-RCT, five CBA studies, very low quality evidence). We found no studies evaluating reliable piped-in water supplies delivered to households. Point-of-use water quality interventionsOn average, distributing water disinfection products for use at the household level may reduce diarrhoea by around one quarter (Home chlorination products: RR 0.77, 95% CI 0.65 to 0.91; 14 trials, 30,746 participants, low quality evidence; flocculation and disinfection sachets: RR 0.69, 95% CI 0.58 to 0.82, four trials, 11,788 participants, moderate quality evidence). However, there was substantial heterogeneity in the size of the effect estimates between individual studies.Point-of-use filtration systems probably reduce diarrhoea by around a half (RR 0.48, 95% CI 0.38 to 0.59, 18 trials, 15,582 participants, moderate quality evidence). Important reductions in diarrhoea episodes were shown with ceramic filters, biosand systems and LifeStraw® filters; (Ceramic: RR 0.39, 95% CI 0.28 to 0.53; eight trials, 5763 participants, moderate quality evidence; Biosand: RR 0.47, 95% CI 0.39 to 0.57; four trials, 5504 participants, moderate quality evidence; LifeStraw®: RR 0.69, 95% CI 0.51 to 0.93; three trials, 3259 participants, low quality evidence). Plumbed in filters have only been evaluated in high-income settings (RR 0.81, 95% CI 0.71 to 0.94, three trials, 1056 participants, fixed effects model).In low-income settings, solar water disinfection (SODIS) by distribution of plastic bottles with instructions to leave filled bottles in direct sunlight for at least six hours before drinking probably reduces diarrhoea by around a third (RR 0.62, 95% CI 0.42 to 0.94; four trials, 3460 participants, moderate quality evidence).In subgroup analyses, larger effects were seen in trials with higher adherence, and trials that provided a safe storage container. In most cases, the reduction in diarrhoea shown in the studies was evident in settings with improved and unimproved water sources and sanitation. AUTHORS' CONCLUSIONS: Interventions that address the microbial contamination of water at the point-of-use may be important interim measures to improve drinking water quality until homes can be reached with safe, reliable, piped-in water connections. The average estimates of effect for each individual point-of-use intervention generally show important effects. Comparisons between these estimates do not provide evidence of superiority of one intervention over another, as such comparisons are confounded by the study setting, design, and population.Further studies assessing the effects of household connections and chlorination at the point of delivery will help improve our knowledge base. As evidence suggests effectiveness improves with adherence, studies assessing programmatic approaches to optimising coverage and long-term utilization of these interventions among vulnerable populations could also help strategies to improve health outcomes.

Can open-defecation free (ODF) communities be sustained? A cross-sectional study in rural Ghana.

Community-led total sanitation (CLTS) is a widely used approach to reduce open defecation in rural areas of low-income countries. Following CLTS programs, communities are designated as open defecation free (ODF) when household-level toilet coverage reaches the threshold specified by national guidelines (e.g., 80% in Ghana). However, because sanitation conditions are rarely monitored after communities are declared ODF, the ability of CLTS to generate lasting reductions in open defecation is poorly understood. In this study, we examined the extent to which levels of toilet ownership and use were sustained in 109 communities in rural Northern Ghana up to two and a half years after they had obtained ODF status. We found that the majority of communities (75%) did not meet Ghana's ODF requirements. Over a third of households had either never owned (16%) or no longer owned (24%) a functional toilet, and 25% reported practicing open defecation regularly. Toilet pit and superstructure collapse were the primary causes of reversion to open defecation. Multivariate regression analysis indicated that communities had higher toilet coverage when they were located further from major roads, were not located on rocky soil, reported having a system of fines to punish open defecation, and when less time had elapsed since ODF status achievement. Households were more likely to own a functional toilet if they were larger, wealthier, had a male household head who had not completed primary education, had no children under the age of five, and benefitted from the national Livelihood Empowerment Against Poverty (LEAP) program. Wealthier households were also more likely to use a toilet for defecation and to rebuild their toilet when it collapsed. Our findings suggest that interventions that address toilet collapse and the difficulty of rebuilding, particularly among the poorest and most vulnerable households, will improve the longevity of CLTS-driven sanitation improvements in rural Ghana.

The Impact of Pro-Poor Sanitation Subsidies in Open Defecation-Free Communities: A Randomized, Controlled Trial in Rural Ghana.

BACKGROUND: According to the World Health Organization/United Nations International Children's Fund Joint Monitoring Program, 494 million people practice open defecation globally. After achieving open defecation-free (ODF) status through efforts such as Community-Led Total Sanitation (CLTS), communities (particularly vulnerable households) may revert to open defecation, especially when toilet collapse is common and durable toilets are unaffordable. Accordingly, there is increasing interest in pro-poor sanitation subsidies. OBJECTIVES: This study determined the impacts of a pro-poor sanitation subsidy program on sanitation conditions among the most vulnerable households and others in the community. METHODS: In 109 post-ODF communities in Northern Ghana, we conducted a cluster randomized controlled trial to evaluate a pro-poor subsidy program that identified the most vulnerable households through community consultation to receive vouchers for durable toilet substructures. We surveyed households to assess toilet coverage, quality, and use before and after the intervention and tracked program costs. RESULTS: Overall, sanitation conditions deteriorated substantially from baseline to endline (average of 21 months). In control communities (not receiving the pro-poor subsidy), open defecation increased from 25% (baseline) to 69% (endline). The subsidy intervention attenuated this deterioration (open defecation increased from 25% to only 54% in subsidy communities), with the greatest impacts among voucher-eligible households. Noneligible households in compounds with subsidized toilets also exhibited lower open defecation levels owing to in-compound sharing (common in this context). CLTS followed by the subsidy program would benefit more households than CLTS alone but would cost 21-37% more per household that no longer practiced open defecation or upgraded to a durable toilet. DISCUSSION: Sanitation declines, often due to toilet collapse, suggest a need for approaches beyond CLTS alone. This subsidy program attenuated declines, but durable toilets likely remained unaffordable for noneligible households. Targeting criteria more closely aligned with sanitation inequities, such as household heads who are female or did not complete primary education, may help to generate greater and more sustainable impacts in Northern Ghana and, potentially, other contexts facing toilet collapse and limited market access. https://doi.org/10.1289/EHP10443.

Assessing the microbiological performance and potential cost of boiling drinking water in urban Zambia.

Boiling is the most common method of disinfecting water in the home and the benchmark against which other point-of-use water treatment is measured. In a six-week study in peri-urban Zambia, we assessed the microbiological effectiveness and potential cost of boiling among 49 households without a water connection who reported "always" or "almost always" boiling their water before drinking it. Source and household drinking water samples were compared weekly for thermotolerant coliforms (TTC), an indicator of fecal contamination. Demographics, costs, and other information were collected through surveys and structured observations. Drinking water samples taken at the household (geometric mean 7.2 TTC/100 mL, 95% CI, 5.4-9.7) were actually worse in microbiological quality than source water (geometric mean 4.0 TTC/100 mL, 95% CI, 3.1-5.1) (p < 0.001), although both are relatively low levels of contamination. Only 60% of drinking water samples were reported to have actually been boiled at the time of collection from the home, suggesting over-reporting and inconsistent compliance. However, these samples were of no higher microbiological quality. Evidence suggests that water quality deteriorated after boiling due to lack of residual protection and unsafe storage and handling. The potential cost of fuel or electricity for boiling was estimated at 5% and 7% of income, respectively. In this setting where microbiological water quality was relatively good at the source, safe-storage practices that minimize recontamination may be more effective in managing the risk of disease from drinking water at a fraction of the cost of boiling.

Will Households Invest in Safe Sanitation? Results from an Experimental Demand Trial in Nakuru, Kenya.

Unsafe sanitation is an increasing public health concern for rapidly expanding cities in low-income countries. Understanding household demand for improved sanitation infrastructure is critical for planning effective sanitation investments. In this study, we compared the stated and revealed willingness to pay (WTP) for high-quality, pour-flush latrines among households in low-income areas in the city of Nakuru, Kenya. We found that stated WTP for high-quality, pour-flush latrines was much lower than market prices: less than 5% of households were willing to pay the full costs, which we estimated between 87,100-82,900 Kenyan Shillings (KES), or 871-829 USD. In addition, we found large discrepancies between stated and revealed WTP. For example, 90% of households stated that they would be willing to pay a discounted amount of 10,000 KES (100 USD) for a high-quality, pour-flush latrine, but only 10% of households redeemed vouchers at this price point (paid via six installment payments). Households reported that financial constraints (i.e., lack of cash, other spending priorities) were the main barriers to voucher redemption, even at highly discounted prices. Our results emphasize the importance of financial interventions that address the sizable gaps between the costs of sanitation products and customer demand among low-income populations.

When pits fill up: Supply and demand for safe pit-emptying services in Kisumu, Kenya.

Improving sanitation conditions in low-income communities is a major challenge for rapidly growing cities of the developing world. The expenses and logistical difficulties of extending sewerage infrastructure have focused increasing attention on the requirements for safe and cost-effective fecal sludge management services. These services, which are primarily provided by the private sector, include the collection and treatment of fecal waste from latrine pits and septic tanks. To determine the degree to which market forces can promote safe fecal sludge removal in low-income neighborhoods of Kisumu, Kenya, we compared household willingness-to-pay for formal pit emptying with the prices charged by service providers. Through surveys of 942 households and a real-money voucher trial with 646 households, we found that stated and revealed demand for formal emptying services were both low, with less than 20% of households willing to pay full market prices. Our results suggest that improving fecal sludge management in these neighborhoods via the private sector will require large subsides, ranging from 55.1-81.4 million KES (551,000-814,000 USD) annually, to address the gap between willingness-to-pay and market prices. Raising and administering subsidies of this scale will require the development of a city-wide sanitation master plan that includes investment, management, and regulatory procedures for fecal sludge management. In the absence of government investment and coordination, it is unlikely that the private sector will address safe sanitation needs in low-income areas of Kisumu.

Assessing the Demand for Plastic Latrine Slabs in Rural Kenya.

Improving access to safe and affordable sanitation facilities is a global health priority that is essential for meeting the United Nation's Sustainable Development Goals. To promote the use of improved sanitation in rural and low-income settings, plastic latrine slabs provide a simple option for upgrading traditional pit latrines. The International Finance Corporation/World Bank Selling Sanitation program estimated that plastic slabs would have a 34% annual growth, with a market size of US$2.53 million in Kenya by 2017. In this study, we examined the commercial viability of these plastic latrine slabs in rural Kenya by evaluating a financing and distribution model intervention, documenting household slab sales to date, and assessing consumer exposure and perceptions. We also determined household willingness to pay through a real-money auction with 322 households. We found that no households in our study area had purchased the plastic slabs. The primary barriers to slab sales were limited marketing activities and low demand compared with the sales price: households were willing to pay an average of US$5 compared with a market price of US$16. Therefore, current household demand for the plastic latrine slabs in rural Kenya is too low to support commercial distribution. Further efforts are required to align the price of plastic latrine slabs with consumer demand in this setting, such as additional demand creation, product financing, and public sector investment.

Are Presence/Absence Microbial Tests Appropriate for Monitoring Large Urban Water Supplies in Sub-Saharan Africa?

Screening for fecal contamination via microbial water quality monitoring is a critical component of safe drinking water provision and public health protection. Achieving adequate levels of microbial water quality testing, however, is a challenge in resource-limited settings. One strategy for addressing this challenge is to improve the efficiency of monitoring programs. In African countries, quantitative microbial testing methods are commonly used to monitor chlorinated piped water systems. However, presence/absence (P/A) tests may provide an appropriate alternative for water supplies that generally show negative fecal contamination results. This study compares 1048 water quality test results for samples collected from five African urban water systems. The operators of the systems conducted parallel tests on the 1048 samples using their standard quantitative methods (e.g., most probable number or membrane filtration) and the Colitag™ method in P/A format. Combined data demonstrates agreement rates of 97.9% (1024/1046) for detecting total coliforms and 97.8% (1025/1048) for detecting E. coli. We conclude that the P/A test offers advantages as a simpler and similarly sensitive measure of potential fecal contamination for large, urban chlorinated water systems. P/A tests may also offer a cost-effective alternative to quantitative methods, as they are quicker to perform and require less laboratory equipment.

Assessment of a low-cost, point-of-use, ultraviolet water disinfection technology.

We describe a point-of-use (POU) ultraviolet (UV) disinfection technology, the UV Tube, which can be made with locally available resources around the world for under $50 US. Laboratory and field studies were conducted to characterize the UV Tube's performance when treating a flowrate of 5 L/min. Based on biological assays with MS2 coliphage, the UV Tube delivered an average fluence of 900+/-80 J/m(2) (95% CI) in water with an absorption coefficient of 0.01 cm(-1). The residence time distribution in the UV Tube was characterized as plug flow with dispersion (Peclet Number = 19.7) and a mean hydraulic residence time of 36 s. Undesirable compounds were leached or produced from UV Tubes constructed with unlined ABS, PVC, or a galvanized steel liner. Lining the PVC pipe with stainless steel, however, prevented production of regulated halogenated organics. A small field study in two rural communities in Baja California Sur demonstrated that the UV Tube reduced E. coli concentrations to less than 1/100 ml in 65 out of 70 samples. Based on these results, we conclude that the UV Tube is a promising technology for treating household drinking water at the point of use.

Efficacy of microbial sampling recommendations and practices in sub-Saharan Africa.

Current guidelines for testing drinking water quality recommend that the sampling rate, which is the number of samples tested for fecal indicator bacteria (FIB) per year, increases as the population served by the drinking water system increases. However, in low-resource settings, prevalence of contamination tends to be higher, potentially requiring higher sampling rates and different statistical methods not addressed by current sampling recommendations. We analyzed 27,930 tests for FIB collected from 351 piped water systems in eight countries in sub-Saharan Africa to assess current sampling rates, observed contamination prevalences, and the ability of monitoring agencies to complete two common objectives of sampling programs: determine regulatory compliance and detect a change over time. Although FIB were never detected in samples from 75% of piped water systems, only 14% were sampled often enough to conclude with 90% confidence that the true contamination prevalence met an example guideline (≤5% chance of any sample positive for FIB). Similarly, after observing a ten percentage point increase in contaminated samples, 43% of PWS would still require more than a year before their monitoring agency could be confident that contamination had actually increased. We conclude that current sampling practices in these settings may provide insufficient information because they collect too few samples. We also conclude that current guidelines could be improved by specifying how to increase sampling after contamination has been detected. Our results suggest that future recommendations should explicitly consider the regulatory limit and desired confidence in results, and adapt when FIB is detected.

Measuring the Impacts of Water Safety Plans in the Asia-Pacific Region.

This study investigated the effectiveness of Water Safety Plans (WSP) implemented in 99 water supply systems across 12 countries in the Asia-Pacific region. An impact assessment methodology including 36 indicators was developed based on a conceptual framework proposed by the Center for Disease Control (CDC) and before/after data were collected between November 2014 and June 2016. WSPs were associated with infrastructure improvements at the vast majority (82) of participating sites and to increased financial support at 37 sites. In addition, significant changes were observed in operations and management practices, number of water safety-related meetings, unaccounted-for water, water quality testing activities, and monitoring of consumer satisfaction. However, the study also revealed challenges in the implementation of WSPs, including financial constraints and insufficient capacity. Finally, this study provided an opportunity to test the impact assessment methodology itself, and a series of recommendations are made to improve the approach (indicators, study design, data collection methods) for evaluating WSPs.