DSpace DSpace

University of Minnesota Digital Conservancy >
University of Minnesota - Twin Cities >
Dissertations and Theses >
Master's Theses (Plan A and Professional Engineering Design Projects) >

Please use this identifier to cite or link to this item: http://hdl.handle.net/11299/140031

Title: Investigation of biologically active granular activated carbon filters.
Authors: Hope Wilkinson, Katheryn Rachel
Keywords: ARISA
Drinking water treatment
Granular activated carbon filters
Issue Date: Sep-2012
Abstract: Geosmin is naturally produced by numerous cyanobacteria and actinomycetes in surface waters. Although it is non-toxic, it causes an unpleasant taste and odor even at very low concentrations. Water utilities, therefore, often must expend great effort and funds to remove geosmin to avoid customer complaints when the compound is present in the source water. Saint Paul Regional Water Services in St. Paul, MN successfully uses granular activated carbon (GAC) filters to remove geosmin from its drinking water, but, curiously, the useful life of their full-scale GAC filters has exceeded estimates based on batch sorption isotherms and AdDesignS modeling. It has been hypothesized that geosmin-degrading microorganisms on the GAC filters degrade geosmin, thereby extending the GAC filter bed life. In this study, the microbial communities growing in full-scale, biologically active GAC filters at Saint Paul Regional Water Services were characterized using automated ribosomal spacer analysis (ARISA) and high throughput DNA sequencing (Illumina sequencing) of 16S rRNA gene fragments. This study showed that Saint Paul Regional Water Services has highly diverse bacterial filter communities that are functionally stable throughout year. Illumina sequencing revealed that a dominatnt bacterial phylum on the GAC filters was Nitrospira and that pathogen levels (e.g., Enterobacteria) were negligible. Additionally, the effects of mediatype and inoculation on the development of a geosmindegrading bacterial community on GAC filters was investigated using a pilot-scale column system that was fed geosmin. A geosmin-degrading biofilm developed after 40 days of being enriched with 100 ng/L of geosmin. Additionally, the geosmin-degrading organisms proved to be robust in that they were able to resume geosmin degradation after 6 weeks when geosmin was absent. The effects of GAC type and inoculation did not impact the biomass levels or geosmin removal.
Description: University of Minnesota M.S. thesis. September 2012. Major: Civil Engineering. Advisors: Dr. Raymond Hozalski and Dr. Timothy LaPara. 1 computer file (PDF); vii, 98 pages, appendices A-G.
URI: http://purl.umn.edu/140031
Appears in Collections:Master's Theses (Plan A and Professional Engineering Design Projects)

Files in This Item:

File Description SizeFormat
HopeWilkinson_umn_0130M_13033.pdf33.55 MBPDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.