Reinforcing feedbacks for sustainable implementation of rural drinking-water treatment technology

Progress towards universal access to safe drinking water depends on rural water service delivery models that incorporate water safety management. Water supplies of all types have high rates of faecal contamination unless water safety risks are actively managed through water source protection, treatment, distribution, and storage. Recognizing the role of treatment within this broader risk-based framing, this study focuses on the implementation of passive chlorination and ultraviolet (UV) disinfection technologies in rural settings. These technologies can reduce health risk from microbiological contaminants in drinking water; however, technology-focused treatment interventions have had limited sustainability in rural settings. This study examines the requirements for sustainable implementation of rural water treatment through qualitative content analysis of 26 key informant interviews, representing passive chlorination and UV disinfection projects in rural areas in South America, Africa and Asia. The analysis is aligned with the RE-AIM framework and delivers insight into 18 principal enablers and barriers of rural water treatment sustainability. Analysis of the interrelationships between these factors identifies leverage points and encourages fit-for-purpose intervention design reinforced by collaboration between facilitating actors through hybrid service delivery models. Further work should prioritize health impact evidence, water quality reporting guidance, and technological capabilities that optimize tradeoffs in fit-for-purpose treatment design

Global prospects to deliver safe drinking water services for 100 million rural people by 2030

The climate crisis and global pandemic have accelerated the urgency of providing safe drinking water services around the world. Global progress to safe drinking water is off-track with uncertain and limited data on the extent and performance of rural water service providers to inform policy and investment decisions. This report documents a global diagnostic survey to evaluate the status and prospects of rural water service providers from 68 countries. The service providers describe providing drinking water services to a population of around 15 million people through over 3 million waterpoints

Results-based funding for safe drinking water services

Rural infrastructure investments have accelerated the installation of decentralised water supply without corresponding investment in the management and oversight of drinking water quality. The assumption that certain types of infrastructure provide safe drinking water has been widely disproven, with faecal and chemical contamination common in piped systems and boreholes. Managing drinking water safety in rural areas is difficult due to the distances involved and the cost implications, with ongoing responsibilities primarily borne by users. As a result, drinking water safety remains unmanaged for much of the global rural population, which coincides with the majority of people living in extreme poverty. Uptime and partners have demonstrated the ability of professional models to improve reliability of water services in rural environments, with results-based funding supporting sustainability and expansion of the services. Recognising that water safety management activities are critical, this working paper presents an approach that advances contracts for results-based funding to incentivise delivery of safe drinking water services. Standardised metrics for water quality, volume, and revenue are proposed within a framework for protected and reliable drinking water services

Assessing microbiological contamination in water sources: Field note on using the UviLux Tryptophan-Like Fluorescence (TLF) Probe

This Field Note provides some practical guidance on the use of tryptophan-like fluorescence (TLF) sensors for assessing water quality in drinking water sources. The guidance is based on experience gained using TLF sensors to assess microbiological contamination risks in groundwater sources used for drinking water in Africa and the Indian Subcontinent. This note covers the use of TLF sensors to make measurements of grab samples from groundwater sources. A suggested reading list of selected research papers that have used TLF sensors in the field is provided at the end of the Note for those interested in further details related to the use of TLF sensors in the field

Tryptophan-like fluorescence as a measure of microbial contamination risk in groundwater

Microbial water quality is frequently assessed with a risk indicator approach that relies on Escherichia coli. Relying exclusively on E. coli is limiting, particularly in low-resource settings, and we argue that risk assessments could be improved by a complementary parameter, tryptophan-like fluorescence (TLF). Over two campaigns (June 2016 and March 2017) we sampled 37 water points in rural Kwale County, Kenya for TLF, E. coli and thermotolerant coliforms (total n = 1,082). Using three World Health Organization defined classes (very high, high, and low/intermediate), risk indicated by TLF was not significantly different from risk indicated by E. coli (p=0.85). However, the TLF and E. coli risk classifications did show disagreement, with TLF indicating higher risk for 14% of samples and lower risk for 13% of samples. Comparisons of duplicate/replicate results demonstrated that precision is higher for TLF (average relative percent difference of duplicates = 14%) compared to culture-based methods (average RPD of duplicates >= 26%). Additionally, TLF sampling is more practical because it requires less time and resources. Precision and practicality make TLF well-suited to high-frequency sampling in low resource contexts. Interpretation and interference challenges are minimised when TLF is measured in groundwaters, which typically have low dissolved organic carbon, relatively consistent temperature, negligible turbidity and pH between 5 and 8. TLF cannot be used as a proxy for E. coli on an individual sample basis, but it can add value to groundwater risk assessments by improving prioritization of sampling and by increasing understanding of spatiotemporal variability

Water chemistry poses health risks as reliance on groundwater increases: a systematic review of hydrogeochemistry research from Ethiopia and Kenya

Reliance on groundwater is increasing in Sub-Saharan Africa as development programmes work towards improving water access and strengthening resilience to climate change. In lower-income areas, groundwater supplies are typically installed without water quality treatment infrastructure or services. This practice is underpinned by an assumption that untreated groundwater is typically suitable for drinking due to the relative microbiological safety of groundwater compared to surface water; however, chemistry risks are largely disregarded. This article systematically reviews groundwater chemistry results from 160 studies to evaluate potential health risk in two case countries: Ethiopia and Kenya. Most studies evaluated drinking water suitability, focusing on priority parameters (fluoride, arsenic, nitrate, or salinity; 18 %), pollution impacts (10 %), or overall suitability (45 %). The remainder characterised general hydrogeochemistry (13 %), flow dynamics (10 %), or water quality suitability for irrigation (3 %). Only six studies (4 %) reported no exceedance of drinking water quality thresholds. Thus, chemical contaminants occur widely in groundwaters that are used for drinking but are not regularly monitored: 78 % of studies reported exceedance of contaminants that have direct health consequences ranging from hypertension to disrupted cognitive development and degenerative disease, and 81 % reported exceedance of aesthetic parameters that have indirect health impacts by influencing perception and use of groundwater versus surface water. Nevertheless, the spatiotemporal coverage of sampling has substantial gaps and data availability bias is driven by a) the tendency for research to concentrate in areas with known water quality problems, and b) analytical capacity limitations. Improved in-country analytical capacity could bolster more efficient assessment and prioritisation of water chemistry risks. Overall, this review demonstrates that universal and equitable access to safe drinking water (Sustainable Development Goal target 6.1) will not be achieved without wider implementation of groundwater treatment, thus a shift is required in how water systems are designed and managed

Multi-messenger searches via IceCube’s high-energy neutrinos and gravitational-wave detections of LIGO/Virgo

We summarize initial results for high-energy neutrino counterpart searches coinciding with gravitational-wave events in LIGO/Virgo\u27s GWTC-2 catalog using IceCube\u27s neutrino triggers. We did not find any statistically significant high-energy neutrino counterpart and derived upper limits on the time-integrated neutrino emission on Earth as well as the isotropic equivalent energy emitted in high-energy neutrinos for each event

In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p