Pathogen removal and use of biosand water filters in the Region Autonoma Atlantico Sur of Nicaragua

This study examined usage of biosand filters amongst 86 families in three different communities in the Región Autónoma Atlántico Sur (RAAS) of Nicaragua. 75% of the families in the study were actively using their filter whilst the remaining 25% no longer used their filter. Pathogen levels (thermotolerant coliforms) were examined in samples of the unfiltered source water, the filtrate and the stored water post-filtration. Average pathogen removal efficiency was 89% and was not significantly higher amongst families who followed the recommended patterns of use of the filter. While the filters in the study typically produced water that was considered safe to drink, recontamination of the stored, filtered water was a significant problem that occurred in 66% of the families. This study affirms the effectiveness of biosand water filters in the field and highlights the need for a focus on prevention of recontamination of the stored, filtered water.