Providing safe drinking water in the developing world has, thus far, been an elusive task and continues to pose an enormous challenge. Approximately 1/5th of the population still lack access to improved drinking water. The situation is most concerning in sub-Saharan Africa, where only 58 percent of the population has access to improved water. Communities within the Njoro River watershed (the study area) typifies high-risk areas relying on grossly contaminated water (average turbidity level of 125 NTU and fecal coliform concentration of 8 x 103 CFU/100 mL). Aid agencies are gradually shifting from centralized solutions to in-home point-of-use (POU) treatment solutions for poor rural and peri-urban communities with inadequate infrastructure and disperse populations. The intermittent slow sand filter (ISSF) has various advantages and has been identified as one of the most promising POU technologies.;The overall goal of this research was to determine the effect of ISSFs on improving health among marginalized communities (specifically communities in the Njoro River watershed). The objective was achieved following a typical three-phase engineering approach. Phase 1 consisted of the effects of inexpensive design parameters to improve ISSF performance through bench scale testing at the University of California, Davis. Phase 2 consisted of pilot testing under close-to-real conditions at Egerton University, Njoro. Phase 3 involved monitoring of a randomized control field level behavioral trial of the ISSF.;Major findings included: (1) ISSF performance was significantly improved through inexpensive measures such as reduction of the effective grain size and nominal head and increased residence time. (2) In-country pilot testing was essential, and revealed unexpectedly low turbidity reductions of the actual river water used by the community for drinking purposes. (3) Intervention households (ISSF users) had significantly better water quality than control households (non-ISSF users). (4) Recontamination due to storage of ISSF treated water in the household was not observed. (5) The risk of diarrhea was reduced by half among children (≤15 years) in the intervention group as compared with the control group. (6) The ISSF was easily incorporated into daily water use routines and habits, and the communities realized the benefits of the ISSF.
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