An assessment of continued use and health impact of the concrete biosand filter in Bonao, Dominican Republic

Abstract

The biosand filter (BSF) is a promising point of use (POU) technology for water treatment; however there has been little follow-up of initial implementation to assess sustainability. The purpose of this study was to examine continued use, performance, and sustainability of previously implemented concrete BSFs in Bonao, Dominican Republic. Of 328 households visited and interviewed, 90% of BSFs were still in use after approximately 1 year since installation. Water-quality improvement, measured by fecal indicator bacteria reduction, was found to be 84-88%, which is lower than reductions in controlled laboratory studies but similar to other field assessments. In a short prospective cohort study comparing BSF to non-BSF households, odds of reported diarrheal disease in BSF households were 0.39 times the odds of reported diarrheal disease in non-BSF households. These results document high levels of sustained and effective concrete BSF use and associated improvements in water quality and health.

Figure 1.

Diagram and timeline of household enrollment and participation in the cross-sectional survey and longitudinal prospective cohort study of concrete BSFs in Bonao, Dominican Republic in 2007.

Figure 2.

Weekly incidence rates of diarrheal disease in concrete BSF and control households for the longitudinal prospective cohort study in Bonao, Dominican Republic, from July to August 2007. *ORs for diarrheal disease are calculated using ordinary logistic regression comparing BSF with control households after adjustment for categorical age. Week 1 (OR = 0.25; CI = 0.07–0.91; sample size = 669) and week 4 (OR = 0.08; CI = 0.01–0.64; sample size = 645) were statistically significant with confidence intervals not crossing the null value of 1.00.