A laboratory investigation was conducted to determine the effects of biologically produced surfactants (biosurfactants) on petroleum hydrocarbons and their potential for the removal of hydrocarbons from groundwater systems. Bioaurfactanta have been found to be produced by microorganisms during growth on insoluble substrates for the purpose of increasing substrate solubility so as to promote biological degradation. In this study, three types of biosurfactants were produced by microorganisms grown on gasoline and a mixture of glucose with vegetable oil. Solubilization and biodegradation of selected gasoline compounds in the presence of bioeurfactante were measured in both static batch and flow through column systems. Batch experiments were conducted in culture tubes, using only liquid phases. A clean sand was used in the column system to monitor physical and chemical interactions yet minimize adsorption effects. A mixed culture of gasoline degrading microorganisms along with isolated cultures grown on selected compounds were used in the biodegradation studies. The biosurfactants produced and used in this study acted similarly to synthetic surfactants and increased, to various degrees, the solubility of the monitored gasoline compounds. Biosurfactants produced from growth on glucose and vegetable oil were very effective surfactants, markedly increasing solubility of the gasoline compounds, but inhibiting biological degradation of these same compounds. Biosurfactants produced by microorganisms from growth on gasoline were effective surfactants, but they did not inhibit biodegradation of the gasoline compounds. This indicated that the biosurfactants may be substrate or microorganism specific, produced for growth on a particular insoluble substrate by a specific microorganism. Biosurfactants produced from growth on gasoline or an insoluble hydrocarbon could therefore be used to enhance solubility and subsequent biodegradation of that same hydrocarbon. The effectiveness of the biosurfactants during application by injection or recirculation for groundwater remediation would be limited by the adsorption and removal of the biosurfactant to the soil. The surfactant demand (by adsorption) of the soil would have to be met before the effects of the biosurfactants would become apparent. Biosurfactanta added to groundwater could also create an additional oxygen demand in a system already low in oxygen. / Master of Science

Increased production of petroleum based products to keep pace with technological advances has taken its toll on the environment. Hydrocarbon contamination of the subsoil and groundwater has become a major problem facing scientists and environmentalists in the 20th century. Initial treatment of contamination sites include the removal of the contaminant from the subsurface for subsequent above ground remediation. Once these methods are exhausted, some type of <i>in-situ</i> remediation, particularly aerobic biodegradation, is sought. Although considered the preferred treatment method, <i>in-situ</i> biodegradation's usefulness is currently limited by oxygen delivery and retention techniques. A novel method of delivering supplemental oxygen to the subsoil, colloidal gas aphrons, has been studied. In addition, this method was compared to the current technique of sparged air injection. The methods and equipment for conducting experimentation on the aeration of an unconfined aquifer, as a vertical slice of soil, have been developed. A specific number of parameters including dissolved oxygen concentration, hydraulic conductivity and tracer dye concentration were measured in order to determine the state of aeration of the saturated soil. Colloidal gas aphrons, CGA, were generated using both NaDBS (sodium dodecylebenzenesulfonate) and Tergitol 15-S-12 surfactants. These dispersions were injected into a 7ft by 7ft by 5in wide two-dimensional vertical slice test cell, which contained about 1600lbs of soil. Continuous dissolved oxygen measurements were conducted using an in-line analysis chamber. Samples were removed through the back of the cell via double-ended shutoff valves and a peristaltic pump. Hydraulic conductivities were monitored to observe variations in fluid flow following the injection of CGA/sparged air. The main conclusions of this work are: l. Both CGA and sparged air introduce dramatic increases in groundwater dissolved oxygen concentrations after injection into the saturated soil. 2. CGA, unlike sparged air/air saturated water, provide supplemental oxygen which forms an "oxygen wall". CGA accumulate near the injection tube forming a stationary front which enhances the dissolved oxygen concentrations of groundwater flowing through the cell. 3. Air sparging does not appear to be as efficient a means of oxygen enhancement of the subsoil as CGA delivery. / Master of Science

Cysteamine (CA), which is an aminothiol drug medically known as Cystagon® was studied in this thesis. Cysteamine was reacted with a binary toxin called peroxynitrite (PN) which is assembled spontaneously whenever nitric oxide and superoxide are produced together and the decomposition of peroxyinitrite was monitored. PN was able to nitrosate CA in highly acidic medium and excess CA to form S-nitrosocysteamine (CANO) in a 1:1 with the formation of one mole of CANO from one mole of ONOOH. In excess oxidant (PN) the following 1:2 stoichiometric ratio was obtained; ONOO- + 2CA → CA-CA + NO2- + H2O . In alkali medium the oxidation of CA went through a series of stages from sulfenic acid, sulfinic acid and then sulfonic acid which was followed by the cleavage of the C-S bond to form a reducing sulfur leaving group, which is easily oxidized to sulfate. The nitrosation reaction was first order in peroxynitrite, thus implicating it as a nitrosating agent in highly acidic pH conditions. Acid catalyzes nitrosation reaction, whitst nitrate catalyzed and increased the amount of CANO product, This means that the nitrosonium cation, NO+ which is produced from the protonation of nitrous acid(in situ) as also contributing to the nitrosation of CA species in highly acidic environments. The acid catalysis at constant peroxynitrite concentrations suggests that the protonated peroxynitrous acid nitrosates at a much higher rate than the peroxynitrite and peroxynitrous acid. Bimolecular rate constants for the nitrosation of CA, was deduced to be 10.23 M-1 s-1. A linear correlation was obtained between the initial rate constants and the pH. The oxidation of CA was modeled by a simple reaction scheme containing 12 reactions.