River nitrate gains from groundwater discharge at waste application fields. Neuse River, North Carolina.

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dc.contributor.advisor William Showers, Committee Chair en_US
dc.contributor.advisor DelWayne Bohnenstiehl, Committee Member en_US
dc.contributor.advisor David Genereux, Committee Member en_US
dc.contributor.author Reyes, Manuel Miguel en_US
dc.date.accessioned 2010-04-02T17:59:41Z
dc.date.available 2010-04-02T17:59:41Z
dc.date.issued 2009-12-03 en_US
dc.identifier.other etd-10172009-171159 en_US
dc.identifier.uri http://www.lib.ncsu.edu/resolver/1840.16/947
dc.description.abstract Nitrate is a common pollutant in rivers worldwide. Samples of groundwater discharging into the Neuse River adjacent the Neuse River Wastewater Treatment Plant (NRWWTP) waste application fields (WAFs) have been measured as high as 86 mg NO3/L. The NC surface water standard is 10 mg NO3/L (N.C. Division of Water Quality, 2007). Geophysical surveys of the NRWWTP WAFs revealed diabase dikes intruded into the granitic bedrock. Groundwater flow is occluded across these dikes; however, fractures around the contact metamorphic zone along these dikes are likely candidates for high groundwater flow. At the NRWWTP, four seasonal sampling periods were conducted at a dike/river crossing in the NW, and one sampling period at another crossing in the E. Samples were analyzed for NO3, NH4, Si, and Cl concentrations. At each sample point, parameters of hydraulic conductivity (K), hydraulic gradient (j) were measured yielding specific discharge (v) and nitrate flux. A ‘hot spot’ of nitrate flux discharging into the river was found downstream of the dike at the NW reach. Using sampling data from each period, a multiquadric radial basis function with anisotropy interpolation was computed and prediction maps for NO3, Si, Cl conc., j, K, v, riverbed elevation, and nitrate flux were made. Assuming an accurate interpolation, the nitrate flux at this ‘hot spot’ was measured in some hydrologic conditions to discharge amounts of nitrate as high as 27 kg NO3/d over an area of 1181.25 m3. This nitrate has an isotopic signature of bio-solid nitrate with denitrification in some areas. In areas of high nitrate, dissolved organic carbon (DOC) concentration was found to be a controlling factor for denitrification. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dis sertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject bio-solids en_US
dc.subject nitrate en_US
dc.subject groundwater en_US
dc.subject nitrogen en_US
dc.subject diabase dike en_US
dc.subject waste application fields en_US
dc.subject groundwater discharge en_US
dc.title River nitrate gains from groundwater discharge at waste application fields. Neuse River, North Carolina. en_US
dc.degree.name MS en_US
dc.degree.level thesis en_US
dc.degree.discipline Marine, Earth and Atmospheric Sciences en_US


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