Date of Award

12-2012

Degree Type

Thesis

Degree Name

Biology (M.S.)

Department

Biology

Abstract

The research presented here is summary two years of studying the Biosand filter (BSF) both in Haiti during March 2011 and in the laboratory. In Chapter 2, we examined the long term use and sustainability 55 BSF systems near Deschapelles, Haiti and 47% were found to be no longer in use. Interviews with BSF owners revealed problems related to intermittent filter use. A review of 17 BSF field studies also was included to compare and substantiate observations made in Haiti. Together, previous field studies and our observations point toward the importance of providing culturally appropriate technologies and education materials explaining proper maintenance and operation for improved filter performance and sustainability.

In Chapter 3, we assessed the E. coli removal efficiency of the 29 functioning BSFs studied in Haiti. Filtered water from 86% of functioning filters contained E. coli concentrations less than 0-10 MPN/100 mL. Bacterial removal efficiency was 94.7% (SE=4.8%). Duration of filter use ranged from <1 to 12 years. Kaplan-Meier analysis of filter lifespans revealed that filter usage remained high (>85%) up to 7 years after installation. Comparable results from previous studies in the same region and elsewhere show that BSF technology continues to be an effective and sustainable water treatment method in developing countries world-wide.

Finally in Chapter 4, we conducted controlled laboratory experiments to analyze filtration efficiencies of the HydrAid® BSF using two field use practices observed while in Haiti: daily filtering more water than the filter media pore space and extended pause periods of 1 to 4 weeks. Six HydrAid® BSFs were divided into two groups of three replicates each to examine both scenarios. Significantly lower filtration efficiencies occurred when dosing volume exceeded the filter media pore space of 15 liters and extended pause periods up to one month had negative effects on filtration efficiencies for about 4 days before returning to normal. Recommendations were made that filter manuals should more accurately reflect the scientific literature that supports these results to limit the amount of potable water per 12 hour period to 15 liters and more strongly encourage daily use of filters without extended pause periods.

Included in

Biology Commons

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