Cluster Randomized Controlled Trial of the Plastic BioSand Water Filter in Cambodia

Abstract

About half of the rural population of Cambodia lacks access to improved water; an even higher percentage lacks access to latrines. More than 35,000 concrete BioSand Water filters (BSF) have been installed in the country. However, the concrete BSF takes time to produce and weighs hundreds of pounds. A plastic BSF has been developed but may not perform to the same benchmarks established by its predecessor. To evaluate plastic BSF performance and health impact, we performed a cluster randomized controlled trial in 13 communities including 189 households and 1147 participants in the Angk Snoul district of Kandal Province from May to December 2008. The results suggest that villages with plastic BSFs had significantly lower concentrations of E. coli in drinking water and lower diarrheal disease (incidence rate ratio 0.41, 95% confidence interval: 0.24-0.69) compared to control villages. As one of the first studies on the plastic BSF in Cambodia, these are important findings, especially in a setting where the concrete BSF has seen high rates of continued use years after installation. The study suggests the plastic BSF may play an important role in scaling up the distribution/implementation of the BSF, potentially improving water quality and health in the region.

A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

“…The findings suggest that the distribution of the filter alone was sufficient to reduce diarrhea outcomes. This finding is consistent with metaregressions by Brown and others,30 Stauber and others,31 and Hunter32 on filter interventions conducted in Asia using ceramic water purifiers (CWPs) and biosand filters (BSFs) 30–32. Results from this study suggest that hollow fiber filters can reduce diarrhea prevalence in children under the age of 5 years an additional 6–13% compared with 72% reported in a study on CWPs in Bolivia 14.…”

“…Compared with the DPR values reported in a study in Cambodia on CWPs (0.58, 95% CI = 0.41–0.82) and iron-rich CWPs (0.65, 95% CI = 0.46–0.93), the diarrheal disease prevalence reductions associated with the PointONE filter seem to be noteworthy 30. Likewise, in another Cambodian study on BSF interventions, a 22% reduction in prevalence of diarrhea was observed, still markedly lower than the effect sizes reported with the PointONE filter 31. Lastly, in a meta-analysis on 33 reports from 21 different countries conducted by Clasen and others,21 chlorination and flocculation disinfection studies estimating the intervention effect in children under 5 years of age using longitudinal prevalence ratios showed that they were less effective (0.91, 95% CI = 0.82–1.02 and 0.42, 95% CI = 0.13–1.37, respectively).…”

A Randomized Controlled Trial of the Plastic-Housing BioSand Filter and Its Impact on Diarrheal Disease in Copan, Honduras

“…However, these results do not document an ability to reduce diarrheal disease in households with a BSF, which has been previously reported, including in other trials of the Hydraid plastichousing BSF. 9,12,13,32 The BSF in this trial was simultaneously tested in Cambodia with a similar study designthey found that, in households with a Hydraid plastic-housing BSF, participants had a 59% reduced risk of diarrheal disease (IRR = 0.41, 95% CI = 0.24, 0.69) and significant improvements in their water quality. 32 It is important to note that, outside of this study, International Aid only promoted the Hydraid plastic-housing BSF in conjunction with safe storage and post-filtration chlorination.…”

Bacterial Contamination on Household Toys and Association with Water, Sanitation and Hygiene Conditions in Honduras

“…Both the concrete and plastic BSF models have recently been shown to improve microbiological water quality in the home and reduce diarrheal disease [13,14,15]. In 2008, researchers conducted an RCT of the plastic BSF in Santa Rosa de Copan, Honduras [13].…”