عنوان

Effect of groundwater velocity and dissolved oxygen on bioremediation of gasoline-contaminated sandy aquifers

Number

TLpq304291292

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Effect of groundwater velocity and dissolved oxygen on bioremediation of gasoline-contaminated sandy aquifers

General Material Designation

[Thesis]

First Statement of Responsibility

N. Mohammed

Name of Publisher, Distributor, etc.

King Fahd University of Petroleum and Minerals (Saudi Arabia)

Date of Publication, Distribution, etc.

1995

Specific Material Designation and Extent of Item

265

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

King Fahd University of Petroleum and Minerals (Saudi Arabia)

Text preceding or following the note

1995

Text of Note

Benzene, Toluene and Xylene (BTX) compounds are the main constituents of gasoline and their presence in groundwater is common because of hydrocarbon spill and leakage of storage tanks. These compounds are relatively highly soluble and mobile in the subsurface and are toxic even at very low concentrations. Bioremediation is the most widely used technique among all the currently employed methods for treating BTX contaminated soil and groundwater. Various factors affecting bioremediation, such as dissolved oxygen, nutrient, temperature, pH, etc. have been well studied in the laboratory soil columns and microcosms. The effect of soil permeability (as groundwater velocity) has been investigated in this study using a pilot scale sand tank model. The effect of dissolved oxygen (DO) and contaminant concentration are also included in the study. Numerical models have been developed using finite difference and orthogonal collocation to simulate one dimensional transport with time-dependent pore water velocity. The modeling process includes sorption given by linear isotherm and biodegradation given by a variety of kinetics such as first-order, zero-order, Monod, Michalis-Menten, Haldane and many other inhibitory and non-inhibitory kinetics. A variety of initial and boundary conditions such as Dirichlet's, Neuman's, mixed, decaying, etc. have been modeled. Three models (first-order and/or zero-order, non growth associated Monod, and Monod) have been inverted using a Gauss-Marquardt-Levenberg algorithm to assess the transport parameter, such as retardation constant (R), first-order rate constant (mu) and zero-order rate constant (usd\gammausd). A 3(22) factorial experiment has been conducted to study three factors, groundwater velocity, BTX concentration and dissolved oxygen (DO). Observed concentration data collected from the sand tank model have been used for estimating the transport parameters. The data has been found to fit well to first-order/zero-order as well as to Monod model. Groundwater velocity has been found to be the most significant factor governing the rate of biodegradation (determined from the first-order rate constant) of BTX compounds. Dissolved oxygen and BTX concentration have also been found to be significant factors.

Applied sciences

Biological sciences

Chemical engineering

Civil engineering

Environmental engineering

Soil sciences

N. Mohammed

Electronic name

p

[Thesis]

276903

a

Y