English

Abstract

Concern over the behavior and remediation of dissolved hydrophobic organic contaminants in groundwater at oil and gas facilities has led to this research investigation. In this study, sorption of PAHs, PCBs, Phenols, benzene, ethylbenzene, toluene and xylenes (BTEX) hydrocarbon from groundwater onto a subsoil core sample was examined as well as their destruction in ClO2/UV solution systems whereby methanol was the carrier solvent. All sorbate-sorbent systems yielded the S-type isotherms indicating co-operative interactions among sorbed organic species. Sorption of the sorbates could be best represented mathematically by the Freundlich equation with 1/n values ranging from 0.4338 to 2.226. Empirical Kf values ranged from 0.89 to 3.049. It is postulated that sorption of sorbates occurs through a combination of hydrogen bonding, dipole-dipole and hydrophobic interactions. Off site travel time for the sorbates ranged from 145 to 80,817 years. Destruction of solutes in UV/ClO2 solution systems is believed to occur through UV quantum vibration enhancement in molecules and free radical processes. Under the most efficient treatment system, 76 to 98% of the chemicals of concern were destroyed. No dioxins or furans were formed as by-products in any of the treatment systems investigated.This highly effective ClO2/UV destructive method has the potential to be applied as a new risk management approach for remediating recalcitrant organic contaminants in impacted groundwater.