When Biosand filters cannot be constructed with crushed quarry rock due to resource limitations, a suitable alternative filter media is needed. In this research, two crushed quarry rock alternatives were examined. Three bench-scale Biosand filters with crushed rock, beach sand, and heat-treated beach sand media were simultaneously dosed with Willamette River water seeded with K-12 E. coli for 31 days. Influent and effluent filtrate was analyzed for E. coli using 3M Petrifilm E. coli/Coliform plate counts; influent and effluent pH, conductivity, turbidity, dissolved oxygen, and temperature were monitored. All three filters achieved stable E. coli removal efficiencies of 99% or greater after filter maturation, suggesting that it is possible to effectively use beach sand and heat-treated beach sand in Biosand filters for pathogenic bacteria removal. Mean effluent E. coli concentrations for crushed rock, beach sand, and heat-treated beach sand filters were 12, 29, and 30 CFU/mL respectively. Crushed rock filter effluent was significantly lower in mean effluent E. coli concentration than beach sand (P < 0.001) and heat-treated beach sand (P < 0.001)
filter effluents, suggesting that beach sand and heat-treated beach sand media should only be used as a secondary option to crushed rock media due to potentially greater exposure risk to pathogenic bacteria. / Graduation date: 2013
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33194 |
| Date | 16 August 2012 |
| Creators | Fulton, Nathan J. |
| Contributors | Wood, Brian D. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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