Date of Award

12-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Mohamed Mostafa Mohamed,

Second Advisor

Aly EI-Kadndi

Third Advisor

Ben Bennani

Abstract

The release of non-aqueous phase liquids (NAPLs) to groundwater reservoirs is a serious and widespread environmental problem. In 2000, free phase hydrocarbon was discovered in Liwa aquifer under Bu Hasa Liquid Recovery Plant (LRP). Liwa aquifer is a shallow unconfined aquifer and represents the main water supply in the camp area of Bu Hasa field. Dissolved benzene is observed in at least one observation well in the site. This research is conducted to simulate the fate and transport of the dissolved benzene plume in the groundwater of Liwa aquifer using the finite element model (METABIOTRANS).

The mam objective of this thesis is to mInImIZe the flux of the dissolved contaminant into the nearest production well downstream of contaminated Liwa aquifer in the camp area. A sensitivity analysis study was performed to assess the sensitivity of the dissolved plume migration to several physical and biological parameters. Results of the sensitivity analysis show that the plume migration is more sensitive to changes in microbial growth rate and substrate half saturation constant and less sensitive to microbial yield factor and dispersion. Different remediation scenarios were performed in which electron acceptor are injected to enhance biodegradation. Remediation scenario with minimum hydrocarbon flux into the camp production wells downstream of the source zone will be suggested as remediation option. The results of the remediation scenarios assured that highest biodegradation rate occurs at injection wells located near the center of the plume where higher contaminant concentrations exist. Placing an injection well near the source zone helps in stimulating the bacterial growth for longer time and therefore, enhances biodegradation. Increasing electron acceptor flux in a well located near the source zone enhances the plume core biodegradation.

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