Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, 913-532-5584
The development of remediation technologies poses a serious challenge for certain classes of compounds, such as polycyclic aromatic hydrocarbons (PAHs). These compounds are hydrophobic and, therefore, readily sorb onto soil. The available technologies, e.g., pump-and-treat, are inefficient for treating hydrophobic compounds because of their low solubilities. A promising approach for circumventing this difficulty is to solubilize such compounds by adding surfactants.
A model has been derived for the system implementing simultaneously the pump-and-treat and rhizosphere technologies for remediating a hydrophobic contaminant. The model is comprised of two zones, the aquifer and rhizosphere, in which all participating material species are uniformly distributed; the contaminant is flushed with an aqueous surfactant solution from the former zone to the latter. The model takes into account dissolution, sorption and biodegradation of the contaminant in the aquifer zone under the assumption that local equilibrium prevails; it also takes into account sorption, mineralization and plant uptake in the rhizosphere zone under the assumption that mineralization obeys Monod's kinetics. Simulation has been performed with the model to determine the effects of surfactant concentration in enhancing the contaminant removal, the number of flushings to remove the contaminant from the aquifer zone, and the time required to degrade the contaminant in the rhizosphere zone.
hydrophobic contaminant, remediation, rhizosphere, surfactant
This paper is from the Proceedings of the 10th Annual Conference on Hazardous Waste Research 1995, published in hard copy and on the Web by the Great Plains/Rocky Mountain Hazardous Substance Research Center.