LNAPL Dissolution in Porous Media and  Dissolution Rate Computations

Asal Gzar, Hatem

	LNAPL Dissolution in Porous Media and Dissolution Rate Computations
Journal of University of Babylon
Article 1, Volume 20, Issue 4, 2012, Pages 1122-1135
Author
Hatem Asal Gzar
Abstract
Benzene is the most toxic of the soluble components of gasoline. It is more mobile than the other aromatic hydrocarbons. Thus, benzene concentrations often determine the need for remedial action in contaminated sites. This paper aims to study the fate of dissolution and transport of benzene in saturated porous media and dissolution rate computations. A three dimensional bench-scale aquifer has been designed and constructed for this purpose. The experiments were conducted under unidirectional flow at different water flow velocities. The results characterized the dissolution behavior and distribution of an entrapped nonaqueous phase benzene source in a three dimensional aquifer model. The time invariant average mass transfer coefficient is determined at each interstitial velocity. The values of this coefficient ranged from 0.016 to 0.061 cm/hr. It is increased proportionally with velocity toward a limiting value. The results showed that the concentration of dissolved benzene reduces as the distance increased in x and/or z direction from the source of pollution. In most cases the concentration values were not stable with time at different values of the interstitial velocity. The dissolution rate of benzene in the aquifer is computed by two methods. The first method is taken from the effluent concentration and flow rate, the second is conducted by using Fick's first law. The resulted dissolution rates from the first method are higher than those of the second one.
Keywords
Benzene; saturated porous media; dissolution; Contamination; dissolution rate; computations

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