Browsing by Author "Dr. Sarah Liehr, Committee Co-Chair"

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    Detection of Ammonia-Oxidizing Beta-Proteobacteria in Swine Waste Treatment Systems.
    (2004-09-17) Smith, Jennifer Mary; Dr. James W. Brown, Committee Member; Dr. Sarah Liehr, Committee Co-Chair; Dr. John J. Classen, Committee Co-Chair
    In order to obtain supporting evidence for biological denitrification in anaerobic lagoons degenerate β-Proteobacterial AOB primers were used to create and sequence clone libraries to detect the presence of ammonia-oxidizing bacteria at three field sites. Although there were PCR products from almost all samples, the clone libraries that were created show that not all PCR reactions produce only PCR products from ammonia-oxidizing bacteria. However, these primers did verify the presence of ammonia-oxidizers at one site, although their presence was not verified at the other sites. The presence of ammonia-oxidizers at the Battelle site implies that aerobic ammonia-oxidation is occurring. Clones were created and sequenced that were significantly different from other known sequences and tended to form very closely related phylogenetic groups. These phylogenetic groups were not isolated to one field site, and often more than one site had representatives in a closely related group. Future research in this field includes the design of new primer sets based on the sequences of the nitrifying bacteria clones reported in this research, creation of enrichment cultures, and use of new primers for fluorescent in situ hybridization.
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    Measuring dinitrogen gas emissions from a lagoon treatment system
    (2004-04-05) Larsen, Julie Melissa; Dr. Sarah Liehr, Committee Co-Chair; Dr. Wayne Robarge, Committee Member; Dr. John Classen, Committee Co-Chair
    A method for collecting dinitrogen gas emissions from open pond waste treatment systems was developed. The method was critically tested in a laboratory for sources of air contamination to ensure reliable gas measurements. A laboratory experiment was done to estimate the rate at which dissolved dinitrogen would be stripped out of solution due to non-dinitrogen bubbles rising through the water column. A volumetric mass transfer coefficient for the process was estimated for clean water. The gas collection method was implemented in a partially aerated lagoon treatment system for dinitrogen and methane gas sampling. The volumetric mass transfer coefficient found in the laboratory for clean water was adjusted to compensate for field gas production rates, temperatures and wastewater quality to estimate the rate of stripped dinitrogen from the partially aerated lagoon. The estimated rate of stripped dinitrogen was subtracted from the total measured dinitrogen flux to estimate the dinitrogen produced biologically. Results from laboratory testing revealed that dinitrogen can be measured with low amounts of dinitrogen atmospheric contamination (0.57% N₂) and the preliminary field results suggest that biological denitrification did occur at this lagoon treatment system.