A pilot study to evaluate efficiency of plastic biosand filtration units in removing coliforms from drinking water: a model for application to rural communities in the developing world

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An undergraduate student project that built a BSF from a plastic garbage pail.
TitleA pilot study to evaluate efficiency of plastic biosand filtration units in removing coliforms from drinking water: a model for application to rural communities in the developing world
Publication TypeThesis
Year of Publication2009
AuthorsBoswell, EN
Academic DepartmentBiology
Date Published2009
CityBoston
AbstractThe UN states that more than 1 billion people have no access to safe drinking water. Biosand filters provide an alternative option for people without access to safe water. This project explores the effectiveness of a plastic unit modeled after the Manz Filter. The objective of this project was to explore the effectiveness for bacterial removal of a plastic trash barrel as an alternative to concrete. The filter was examined under semi-continuous and intermittent use. River water in Boston, MA was tested. Coliform contamination was analyzed before and after filtration. Water was collected three times a week and tested using a multiple tube fermentation test and Most Probable Number count. Presence of fecal coliforms was also evaluated. Descriptive statistical analysis was performed. Mean and median coliform counts for unfiltered water were 291.25 and 290. Mean and median coliform counts for filtered water were 4 and 3 indicating that the filter produced significant reductions in coliform counts. All unfiltered samples were positive for fecal coliforms. They were absent from 6 out of 8 filtered samples. Using coliforms removed divided by total coliforms the unit maintains 98% removal efficiency. The plastic Biosand filter proved to be effective in reducing the coliform count. CAWST (20) indicates 98% removal efficiency for E. coli for the Manz concrete system. Our results meet that level of efficiency; we observed a significant trend towards removal of both coliforms and fecal coliforms. Further sampling will be performed to confirm the removal efficiency of the plastic filter unit.

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