Download Full Text (377 KB)
Civil and Environmental Engineering
Although biosand filters (BSFs) have been implemented in over 55 countries to provide safe drinking water, the necessity of operating filters on a daily basis has raised questions about filter efficacy after a period of abandonment (e.g., due to travels away from home or school vacations when students/faculty are not present to use institutional filters every day). Presently, the safe recommendation for abandoned filters is to deconstruct and rebuild. An assessment of the effectiveness of revitalized BSFs was conducted on two full-scale concrete BSFs, two 5-gallon bucket BSFs, and two 2-gallon bucket BSFs that were abandoned for two years. The filters were revitalized by rehydration (as needed), swirl-and-dump sand cleaning, tubing disinfection, and flushing. The performance of the revitalized filters was compared to that of two newly built concrete filters by measuring influent and effluent levels of Escherichia coli, Cryptosporidium parvum oocysts, and turbidity. Influent water was collected from a local creek to provide adequate nutrients to support biolayer development and to emulate field use. The log removal of E. coli and C. parvum by each filter was calculated by testing the two subsequent effluents following each spike. In addition, turbidity of each influent and effluent was measured to determine percent reduction. Flow rates of the filters, as well as water quality measurements of influent and effluent water (i.e., conductivity, phosphates, ammonia, total nitrogen), were evaluated weekly. The data show that revitalized BSFs are comparable to newly built filters, simplifying the continued use of drinking water treatment systems in developing nations.
Fedun, Michelle; Fletcher, Cathy; Heinbokel, Leigh; and Mejia, Kristen, "Revitalization of Abandoned Biosand Filters" (2016). David and Lorraine Freed Undergraduate Research Symposium Winning Posters. 4.