Thesis jointly supervised by the University of Western Brittany. PhD jointly supervised by: Michel MOAN, professeur à l'UBO
Committee: Michel GIRIN, Jean OUDOT, Kenneth LEE, Nathalie POUPART, François-Xavier MERLIN
Abstract: Experience shows that spills of heavy fuel oils are among the most difficult to combat. Their persistence as well as changes in chemical composition when stranded on hard substrates was studied through experiments performed in laboratory, pilot scale, in situ and under real condition, by sampling of Erika's oil remaining on Atlantic shores. Adhesion of heavy fuel oil is higher and remobilisation from substrate to water columm weak when the viscosity increase. The porosity of substrate decreases the remobilisation kinetics. Roughness of substrate allows a higher adhesion of the pollutant which is easily remobilized due to wave's action. Moreover, due to its significant amount of aromatics compounds, heavy fuel oil is sensitive to solar radiations. Samples exposed to solar radiation loose their elasticity and were more sensitive to abrasive remobilisation due to the presence of sediments of biodegradation kinetic and a decrease of photo-oxydation kinetic. A weathering index was defined with the experimental results and used, in real condition, in order to assess statistically the influence of environmental parameter on the degradation process kinetics. Five years after the Erika's spill, the total degradation rate of the heavy fuel oil remaining on Atlantic shores reach 50 % when stranded on environments exposed to solar radiation : pollutant looks like asphalt with a high amount of polar compounds. When stranded on environments not exposed to solar radiation, the total degradation rate reach not more 16 %.
Bibliographical reference: www.cedre.fr/pmb/opac_css/index.php?lvl=notice_display&id=4298