Online Program

Laboratory and field studies to compare fecal coliform counts in water from biosand filters following periods of either intermittent use or following a pause in use in Boston MA and san juan del Sur, Nicaragua

Wednesday, November 6, 2013

Kathleen Mudie, Biology/Undergraduate program in public health, Simmons College, Boston, MA
Aris Walker, Biology/Undergraduate program in public health, Simmons College, Boston, MA
Elizabeth Scott, PhD, Biology & Undergraduate Program in Public Health, Simmons College, Boston, MA
Guidelines indicate that biosand filters should be primed with source water every two days and not paused for longer than 48h1. Once paused, it is not clear how quickly the filters can be re-primed. The efficacy of filters following intermittent priming and re-priming following pause is reported here. River water in Boston was filtered through a plastic filter and field testing was conducted on disused, re-primed concrete filters in Nicaragua. All filters were based on CAWST specifications1. Fecal coliform counts were analyzed from source and filtered water. The water was tested using either MPN count or membrane filtration. Intermittent mean data ranged from 99.7% and 99.8% removal of fecal coliforms whereas re-primed data for a paused plastic filter ranged from 92%-98.3%, mean 95.5%. This did not meet MANZ standards but fell within WHO ‘low risk' for drinking water in developing countries2. For re-primed concrete filters in Nicaragua, the mean fecal coliform count in well water samples was 647/100 ml. The mean count in filtered water samples was 17/100 ml. Of eight filters tested, three showed zero fecal coliforms, giving an average 96.95% removal efficiency. The filters that did not meet MANZ and WHO standards were those where the source water was most heavily contaminated. Of eight concrete filters tested following pause, removal efficiency ranged from 88% to 100%. Whilst all of the re-started filters showed reduction in fecal coliforms compared to source water, further investigation is required to better understand why some of the paused, re-primed biosand filters under-performed

Learning Areas:

Environmental health sciences

Learning Objectives:
Describe the action of a biosand filter and why intermittent use and pauses in use can negatively impact the effectiveness of the filter. Compare different methods of water testing. Observe two different types of filter construction. Assess the effectiveness of re-priming with source water after pauses in filter use

Keyword(s): Water Quality, Developing Countries

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am an undergraduate student in the Department of Biology at Simmons college, majoring in Public Health. I received internal funding to begin my research project on biosand filters in 2012 and I traveled to Nicaragua to do the field studies in January 2013. I do my research in collaboration with Professor Elizabeth Scott
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.