Dissolution rate coefficients for surface slicks on rivers

The aqueous concentrations of oils, fuels and solvents resulting from river ine spills are highly dependent upon the dissolution rate coefficients, on which there is little information available. The water-film mass transfer r are coefficient was measured for the dissolution of a hexane slick in a sti rred cylinder and in an oscillating grid chamber. In both devices, the turb ulence was generated beneath the oil-water interface, similar to the bed-ge nerated turbulence in rivers. The liquid-film coefficient was also measured during reaeration studies, conducted without a surface slick under the sam e conditions. In comparing the coefficients measured with a slick and witho ut, the presence of the surface slick was found to have minimal impact on t he water-film mass transfer coefficient after indexing properly with the Sc hmidt number. Thus, the dissolution rate coefficient for any compound can b e easily predicted from the reaeration rate coefficient for a given river r each. Additionally, no scale effects were detected between the between the 4 L stirred cylinder and the 87 L oscillating grid chamber (C) 1999 Elsevie r Science Ltd. All rights reserved.