Field efficacy evaluation and post-treatment contamination risk assessment of an ultraviolet disinfection and safe storage system.

Inconsistent use of household water treatment and safe storage (HWTS) systems reduces their potential health benefits. Ultraviolet (UV) disinfection is more convenient than some existing HWTS systems, but it does not provide post-treatment residual disinfectant, which could leave drinking water vulnerable to recontamination. In this paper, using as-treated analyses, we report on the field efficacy of a UV disinfection system at improving household drinking water quality in rural Mexico. We further assess the risk of post-treatment contamination from the UV system, and develop a process-based model to better understand household risk factors for recontamination. This study was part of a larger cluster-randomized stepped wedge trial, and the results complement previously published population-level results of the intervention on diarrheal prevalence and water quality. Based on the presence of Escherichia coli (proportion of households with ≥ 1 E. coli/100 mL), we estimated a risk difference of -28.0% (95% confidence interval (CI): -33.9%, -22.1%) when comparing intervention to control households; -38.6% (CI: -48.9%, -28.2%) when comparing post- and pre-intervention results; and -37.1% (CI: -45.2%, -28.9%) when comparing UV disinfected water to alternatives within the household. We found substantial increases in post-treatment E. coli contamination when comparing samples from the UV system effluent (5.0%) to samples taken from the storage container (21.1%) and drinking glasses (26.0%). We found that improved household infrastructure, additional extractions from the storage container, additional time from when the storage container was filled, and increased experience of the UV system operator were associated with reductions in post-treatment contamination. Our results suggest that the UV system is efficacious at improving household water quality when used as intended. Promoting safe storage habits is essential for an effective UV system dissemination. The drinking glass appears to represent a small but significant source of recontamination that is likely to impact all HWTS systems

Drivers of Microbial Risk for Direct Potable Reuse and de Facto Reuse Treatment Schemes: The Impacts of Source Water Quality and Blending.

Although reclaimed water for potable applications has many potential benefits, it poses concerns for chemical and microbial risks to consumers. We present a quantitative microbial risk assessment (QMRA) Monte Carlo framework to compare a de facto water reuse scenario (treated wastewater-impacted surface water) with four hypothetical Direct Potable Reuse (DPR) scenarios for Norovirus, Cryptosporidium, and Salmonella. Consumer microbial risks of surface source water quality (impacted by 0-100% treated wastewater effluent) were assessed. Additionally, we assessed risks for different blending ratios (0-100% surface water blended into advanced-treated DPR water) when source surface water consisted of 50% wastewater effluent. De facto reuse risks exceeded the yearly 10-4 infections risk benchmark while all modeled DPR risks were significantly lower. Contamination with 1% or more wastewater effluent in the source water, and blending 1% or more wastewater-impacted surface water into the advanced-treated DPR water drove the risk closer to the 10-4 benchmark. We demonstrate that de facto reuse by itself, or as an input into DPR, drives microbial risks more so than the advanced-treated DPR water. When applied using location-specific inputs, this framework can contribute to project design and public awareness campaigns to build legitimacy for DPR

States Taking Charge: Examining the Role of Race, Party Affliation, and Preemption in the Development of in-state tuition laws for undocumented immigrant students

Part I of this Article details both the legislative and legal history of undocumented immigrants’ access to education in the United States. Part II then describes the current U.S. state laws in effect regarding in-state tuition for undocumented immigrant students at state-funded colleges and universities. Part III further explores the development of laws and policies with a keen focus on potential correlations between (1) the racial composition of state legislatures and the passage of in-state tuition policies; (2) the race of governors and the passage of in-state tuition policies; (3) partisan composition of state legislatures and the passage of in-state tuition policies; and (4) party affiliation of governors and in-state tuition policies. Part IV describes the concept of preemption and discusses the extent to which preemption has impacted the state statutes identified in Part II of this Article. Finally, Part V discusses the practical and normative implications of this research

States Taking Charge: Examining the Role of Race, Party Affliation, and Preemption in the Development of in-state tuition laws for undocumented immigrant students

Part I of this Article details both the legislative and legal history of undocumented immigrants’ access to education in the United States. Part II then describes the current U.S. state laws in effect regarding in-state tuition for undocumented immigrant students at state-funded colleges and universities. Part III further explores the development of laws and policies with a keen focus on potential correlations between (1) the racial composition of state legislatures and the passage of in-state tuition policies; (2) the race of governors and the passage of in-state tuition policies; (3) partisan composition of state legislatures and the passage of in-state tuition policies; and (4) party affiliation of governors and in-state tuition policies. Part IV describes the concept of preemption and discusses the extent to which preemption has impacted the state statutes identified in Part II of this Article. Finally, Part V discusses the practical and normative implications of this research

Developing Human Wellbeing Indicators in the Hood Canal Watershed

Planning for and monitoring human wellbeing as a component of ecosystem recovery is a growing trend in coastal zone management. Within the Puget Sound specifically, organizations at the watershed and basin scale have been developing recovery action plans with placeholders for human wellbeing or quality of life indicators. While the actual incorporation of human wellbeing into policy has been limited, there is significant interest to receive guidance for developing indicators and begin addressing human wellbeing in practice. This article describes the results of a pilot process to develop scientifically and practically relevant human wellbeing indicators for the Hood Canal watershed of the Puget Sound. We gathered data on why residents and visitors value the Hood Canal from prior surveys, workshops, and nineteen open-ended interviews with diverse residents from the region. We coded these values into potential indicators of human wellbeing for seven domains: Psychological, Spiritual, Cultural, Social, Physical, Economic, and Governance. Three facilitated workshops with expert-stakeholders and an online survey with social scientists helped refine and rate indicators for recommendation to the regional watershed recovery coordinating council. We present the final indicators, detail the methods for getting to them, and discuss how they will be applied to enhance watershed recovery in the Hood Canal and larger Puget Sound Basin

Water quality effects of intermittent water supply in Arraiján, Panama

Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause waterquality to degrade in the distribution system.In this study,we characterized waterquality in one study zone with continuous supply and three zoneswith intermittentsupply in the drinking waterdistribution network in Arraija!n,Panama.Low orzero pressuresoccurred in allzones,and negative pressuresoccurred in the continuouszone and two ofthe intermittentzones.Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samplescollected atrandom timeswere positive fortotalcoliform bacteria and only one waspositive for E.coli.Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had !0.2 mg/L free chlorine residual.In contrast,water quality was often degraded during the first-flush period (when supply first returned after an outage).Still, routine and first-flush water quality under intermittent supply was much better in Arraija!n than that reported in a previous study conducted in India.Better waterquality in Arraija!n could be due to betterwaterquality leaving the treatmentplant,shortersupply outages,highersupply pressures,a more consistentand higherchlorine residual,and fewercontaminant sourcesnearpipes.The resultsillustrate thatintermittentsupply and itseffectson waterquality can vary greatly between and within distribution networks.The study also demonstrated thatmonitoring techniques designed specifically for intermittentsupply,such as continuous pressure monitoring and sampling the firstflush,can detectwaterquality threats and degradation thatwould notlikely be detected with conventionalmonitoring.Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause waterquality to degrade in the distribution system.In this study,we characterized waterquality in one study zone with continuous supply and three zoneswith intermittentsupply in the drinking waterdistribution network in Arraija!n,Panama.Low orzero pressuresoccurred in allzones,and negative pressuresoccurred in the continuouszone and two ofthe intermittentzones.Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samplescollected atrandom timeswere positive fortotalcoliform bacteria and only one waspositive for E.coli.Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had !0.2 mg/L free chlorine residual.In contrast,water quality was often degraded during the first-flush period (when supply first returned after an outage).Still, routine and first-flush water quality under intermittent supply was much better in Arraija!n than that reported in a previous study conducted in India.Better waterquality in Arraija!n could be due to betterwaterquality leaving the treatmentplant,shortersupply outages,highersupply pressures,a more consistentand higherchlorine residual,and fewercontaminant sourcesnearpipes.The resultsillustrate thatintermittentsupply and itseffectson waterquality can vary greatly between and within distribution networks.The study also demonstrated thatmonitoring techniques designed specifically for intermittentsupply,such as continuous pressure monitoring and sampling the firstflush,can detectwaterquality threats and degradation thatwould notlikely be detected with conventionalmonitoring

Household stored water quality in an intermittent water supply network in Panama

Safe water storage is critical to preserve water quality, especially when intermittent piped drinking water supply creates a need for household storage. This study characterized household storage practices and stored water quality in 94 households (N = 94) among four peri-urban neighborhoods in Arraiján, Panama with varying degrees of supply intermittency. We found that 18 (19.1%) households stored drinking water in unsafe containers. Forty-four (47%) samples of household stored drinking water had residual chlorine levels 10 most probable number (MPN)/100 mL total coliform bacteria. Eight (44%) samples were positive for Escherichia coli, whereas only one (1.3%) sample from the safe containers was positive. Twenty-nine (30.9%) samples had >500 MPN/mL heterotrophic plate count bacteria. These findings suggest that longer supply interruptions were associated with longer storage times and lower chlorine residual, which were associated with higher concentrations of indicator bacteria. This is one of the first studies in the Central-American region to show an association between the lack of turnover (replacement with fresh water) and greater contamination during household water storage. Thus, when drinking water supply is not completely continuous and household storage is required, decreasing the time between supply periods can facilitate safer water storage. Public awareness and education are also recommended to increase hygiene practices during water collection and storage.Safe water storage is critical to preserve water quality, especially when intermittent piped drinking water supply creates a need for household storage. This study characterized household storage practices and stored water quality in 94 households (N = 94) among four peri-urban neighborhoods in Arraiján, Panama with varying degrees of supply intermittency. We found that 18 (19.1%) households stored drinking water in unsafe containers. Forty-four (47%) samples of household stored drinking water had residual chlorine levels 10 most probable number (MPN)/100 mL total coliform bacteria. Eight (44%) samples were positive for Escherichia coli, whereas only one (1.3%) sample from the safe containers was positive. Twenty-nine (30.9%) samples had >500 MPN/mL heterotrophic plate count bacteria. These findings suggest that longer supply interruptions were associated with longer storage times and lower chlorine residual, which were associated with higher concentrations of indicator bacteria. This is one of the first studies in the Central-American region to show an association between the lack of turnover (replacement with fresh water) and greater contamination during household water storage. Thus, when drinking water supply is not completely continuous and household storage is required, decreasing the time between supply periods can facilitate safer water storage. Public awareness and education are also recommended to increase hygiene practices during water collection and storage