This study investigated the capability of vacuum UV to reduce the concentration of cyanobacterial toxin microcystin-LR (MC-LR) using low-pressure Hg lamps emitting 185 nm and 254 nm light. A collimated beam setup was used to irradiate samples of MC-LR solutions prepared in Milli-Q® water. The impact of competing water compounds was tested using solutions containing dissolved organic carbon (DOC), alkalinity (NaHCO3), and chloride (NaCl). Results showed that MC-LR in pure water at typical concentrations found in cyanobacterial bloom waters (17 and 40 μg/L) could be reduced below detection limits (0.5 μg/L) within one minute of irradiation time by a UV dose less than 40 mJ/cm2. A solution with a much higher initial concentration of MC-LR (870 μg/L) did show a reduced degradation rate. The presence of competing compounds does appear to reduce observed MC-LR degradation rates with the greatest impact caused by DOC followed by alkalinity followed by chloride. MC-LR degradation appears to occur by both direct photolysis by 254 nm photons and by advanced oxidation by hydroxyl radicals generated from 185 nm photons. Vacuum UV has shown promising capability at reducing MC-LR concentration.
Water stress is increasingly affecting hundreds of millions of people around the world. In East Africa, severe and persistent drought periods negatively impact health and livelihoods. Drought increases reliance on mechanized boreholes to extract groundwater. However, without adequate resource allocations, effective monitoring of borehole functionality, and reliable maintenance service, breakdown rates increase and downtimes last many months. Our study applies system dynamics modeling to investigate the effects of allocating resources to borehole maintenance and repair in the Afar Region in Ethiopia and Turkana County in Kenya. We inform model calibration with runtime and functionality estimates derived from sensors installed on 245 boreholes and apply sensitivity analyses varying budget allocations to optimize for functionality. We conclude that increasing the borehole repair and maintenance budgets in Turkana from the current 30% to 85% of available budgets could result in an additional 83 working boreholes and 95% functionality in 2030. In Afar, increasing maintenance budgets from 38% to 79% could result in functionality levels of 75% by 2030, well above currently projected levels of 54%.
While preventive maintenance services have emerged as promising interventions to improve the continuity of water service delivery, the operational and contextual requirements for sustained functionality within maintenance models are not well understood. This paper uses data analysis to better understand factors influencing the success of rural water service delivery within the circuit rider maintenance model in fragile contexts. Incorporating operational data from a large scale circuit rider hand-pump maintenance program in the Central African Republic, mixed-effect logistic regression models were used to identify determinants of water point functionality and payment compliance. Models were informed by data from over 16,000 maintenance visits across nine years. Faster response time, proximity to urban centers, and proximity to other hand-pumps emerged as significant factors for improving water point functionality, while proximity to maintenance program headquarters, pump functionality, and frequency of maintenance visits significantly influenced payment compliance. The observed high functionality rates of hand-pumps serviced by the maintenance program indicates the potential benefits of professionalized maintenance through the circuit rider model at promoting water system reliability in fragile contexts. Despite adaptability and resilience in implementation of the circuit rider model, insecurity and conflict remain barriers to sustaining service delivery in the Central African Republic.
Reliable water service delivery continues to be a complex global issue that is particularly challenging in rural communities. Despite billions of dollars of infrastructure interventions, sustainable water services remain out of reach for millions of people. Professionalized maintenance services have emerged as a service provision strategy to supplement the community-based rural water management approach. This study applies system dynamics modeling to assess the potential impact of scaling up professionalized maintenance services on piped water systems in Kitui County, Kenya. The study results show that over a 10 year simulation, calibrated with 21 months of empirical data and based on a range of key assumptions, delivery of professionalized maintenance services across the county may increase countywide functionality rates from 54% to over 83%, leading to a 67% increase in water production. Furthermore, the increase in preventive maintenance activities and proactive repairs can lead to less frequent major breakdowns and reduction in county government spending on major repairs by over 60%. However, current service fee income from communities accounts for 8% of the total cost of service, necessitating substantial sustained external financing or government subsidies to be financially viable at scale.
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