Quantitative and qualitative evaluation of compost is necessary in order to provide consumers with basic knowledge about the products composition, and to protect public health and the environment by preventing the spread of contaminated material. Current methods for analysis of basic compost properties give accurate results but are time consuming and require numerous laboratory procedures. This study evaluated the use of visible near-infrared diffuse reflectance spectroscopy (VisNIR DRS) for organic matter (OM) determination and field portable X-ray fluorescence (PXRF) spectroscopy for determination of elemental composition of composted materials. These technologies were evaluated as alternatives to standard laboratory methods for their use in rapid in situ analysis. Thirty-six compost samples from a wide range of feedstocks were gathered and tested with VisNIR DRS and PXRF. For VisNIR DRS, the influence of sample moisture on scanning results was evaluated and the use of raw reflectance, first-derivatives, and second-derivatives of the reflectance spectra were compared. Partial least squares regression (PLS) and principal component regression (PCR) were used to build regression models of VisNIR DRS scans and lab measured OM. For PXRF, the influences of sample moisture, particle size, inter-elemental interactions, and OM on PXRF scanning results were investigated. Results from the VisNIR DRS study produced a promising r2 value of 0.82 and residual prediction deviation (RPD) value of 1.72 for the ovendried first-derivative PLS model. Results indicate that VisNIR DRS shows great promise as a technique for analysis of OM content of dried compost samples, however further investigation with a larger sample set is necessary before VisNIR DRS can replace laboratory methods. Results of PXRF for elemental analysis were most promising for dried samples and for determining the elements Ca, Cr, Cu, Fe, K, Mn, P, and Zn. Arsenic detection was found to be greatly limited due to the influence of elevated Pb concentrations in the samples. Additionally, sample moisture, particle size, and
OM were found to have varying influences on PXRF scan results for different elements. Compost elemental screening and definitive quantification of certain elements via PXRF is recommended by this study.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-06252012-100224 |
| Date | 28 June 2012 |
| Creators | McWhirt, Amanda Lynne |
| Contributors | Weindorf, David, Motsenbocker, Carl, Sabliov, Cristina |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-06252012-100224/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, 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 LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, 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. |
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