Date of Award

1998

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

First Advisor

John H. Pardue

Abstract

The biodegradation of the crude oil in a salt marsh was monitored by tracking the decline of the ratio of various components in the crude oil to a stable marker, hopane. In studies of mesocosms, addition of nitrogen as ammonium nitrate resulted in more rapid biodegradation of the oil at 0.10 significance. In field plots, addition of nitrogen was found to not significantly increase the rate of oil degradation over the rate in the control plots. The degradation of the oil is best described by a first order decay equation. The kinetic rate parameter k was 0.0054/day in the control field plots. Average kinetic parameters for control plots for various n-alkanes, from dodecane to dotriacontane were within the range of 0.0034 to 0.0078/day. Kinetic parameters for the mesocosms were approximately three times faster than for the field plots. The findings are strictly applicable only to the conditions of the research, i.e., Louisiana sweet crude oil, application rate of 1.16 kg/square meter, a salt marsh populated by Spartina alterniflora, and application of the oil in late summer. The findings may, however, be considered a point of beginning for similar but not identical situations. While nutrient addition to the field plots was not significantly beneficial to biodegradation under the subject conditions, under other situations it may offer significant improvement of degradation rates. A logic diagram to determine whether a given spill in a marsh should have nutrients added is presented. A scenario with a work plan and budget outline to conduct a pilot nutrient application in the case where nutrient addition is indicated as beneficial is presented in Appendix H. The scenario continues through budget preparation for full scale field application of the nutrients.

ISBN

9780599213258

Pages

208

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