DISSOLUTION OF BENZENE IN THE SATURATED POROUS MEDIA

Abstract

The aim of the present research is to study the dissolution and transport process ofbenzene as a light nonaqueous phase liquid (LNAPL) in saturated porous media.Unidirectional flow at water velocities ranged from 0.90 to 3.60 cm/hr was adopted to studythis process in a three dimensional saturated sand tank (100 cm×40 cm×35 cm). This tankrepresents a laboratory-scale aquifer. The aquifer was constructed by packing homogeneoussand in the rectangular tank. The experimental results were used to characterize thedissolution behavior of an entrapped nonaqueous phase benzene source in a three dimensionalaquifer model. The time invariant average mass transfer coefficient was determined at eachinterstitial velocity, the values of this coefficient were ranged from 0.016 to 0.061 cm/hr. Itwas increased proportionally with velocity toward a limiting value. The results show that theconcentration of the LNAPL reduces as the distance increased in x and/or z direction from thesource of pollution. In most cases the benzene concentration declines with velocity more than2.34 cm/hr at downstream of the LNAPL pool.