Engineering Commons^™

Anaerobic Toluene Biodegradation Potential At A Superfund Site Where Toluene Biosynthesis Was Observed, George Carson

LSU Master's Theses

At a Superfund site near Baton Rouge, LA, the subsurface injection of molasses has been used to stimulate anerobic reductive dechlorination of halogenated organic compounds (e.g., 1,2-dichloroethane and vinyl chloride) present in the groundwater. Following some molasses injections, temporary accumulation of toluene and p-cresol was observed in the groundwater. Accumulation of these aromatic hydrocarbons, which were not detected in the molasses, has been attributed to anaerobic biotransformation of the amino acids phenylalanine and tyrosine. Experiments reported here were conducted in support of an effort to determine if toluene biodegrading bacteria were present in the area where anaerobic toluene accumulation was …

P-Cresol Biogenesis During Bioremediation Aimed At Stimulating Chlorinated Solvent Dehalogenation, Alexis Gathings

LSU Master's Theses

The broad goal of the research described in this thesis was to better understand the potential for biologically mediated production of p-cresol in groundwater at a Superfund site located in south Louisiana. Previous literature reports that microorganisms known to carry out the transformation from L-tyrosine to p-cresol occur in diverse environments.

In the research described in this thesis, studies were conducted utilizing groundwater from the Superfund site during the course of enhanced in situ bioremediation practices aimed at stimulating reductive dehalogenation of chlorinated solvent contamination. Microbial communities established with groundwater sampled from the Superfund site were observed to …

Coupled Chemical Pre-Oxidation And Aerobic Bioremediation Of Buried Mc252 Oil Across A Headlands Beach Profile, Olivia Bramlet

LSU Master's Theses

The release of MC252 crude oil following the Deepwater Horizon event has emphasized the need to investigate factors controlling the extent of contamination degradation in coastal environments. Dam structures created on Fourchon Beach, LA established conditions for PAH and n-alkane accumulation and burial along a vertical profile that persists today due to the anaerobic, often anoxic, and hypersaline conditions of the groundwater. The ability to remove the oxygen limitation present on in situ aerobic biodegradation of buried petroleum-based hydrocarbons in this environment was investigated through the coupled process of chemical oxidation and enhanced bioremediation using a proprietary formulation of activated …

Biodegradation Of Buried Mc252 Oil In Coastal Beach Sands By Pah Degraders In Response To Oxygen Biostimulation, Leeann Renee Fitch

LSU Master's Theses

Six years following the Deepwater Horizon oil spill, buried MC252 oil persists on a beach segment in Fourchon, LA due to the natural anaerobic conditions of tidal groundwater. A field trial of in situ aerobic bioremediation of buried oil began on July 2015. Oxygen was added to the subsurface using Waterloo emitters which deliver O2 through diffusion via pressurized tubing in fixed groundwater wells. The multi-well injection system provided sufficient oxygen concentration in the groundwater in the immediate area of the emitters, resulting in a shift in the composition of the diverse, halophilic, hydrocarbon-degrading microbial population. Stable isotopic and radiocarbon …

Spatial Biodegradation Of Mc252 Crude Oil On A Coastal Headland Beach, Zachary Joseph Romaine

LSU Master's Theses

Following the Deepwater Horizon oil spill in April, 2010, hard structures were constructed to deter oil migration into sensitive marsh areas behind Fourchon Beach, LA These hard structures created conditions for accumulation and burial of oil across an 8 foot deep beach vertical profile. Buried oil persists in these areas due to anaerobic conditions of beach groundwater. The objectives of this thesis are to compare the rate and extent of biodegradation of 3-ring PAHs in crude oil deposits from the surface and subsurface, and to investigate effects on beach groundwater after introduction of O2. Field samples were removed from 2011-2016 …

A Sustainable Remediation Approach For Complete Destruction Of Chloroethanes In Groundwater, Michael Joseph Cheatham

LSU Master's Theses

An up-flow column study was operated in a greenhouse composed of a sand/peat mixed media to investigate the effectiveness of an aerobic zone on the disappearances of chloroethane. The oxygen was supplied by mean of porous Silastic tubing under pressure with a breathing air gas cylinder. Chloroethane was generated via reductive dechlorination of 1,1,1-trichloroethane (TCA) and 1,1-dichloroethane (DCA) in anaerobic bioreactors (ABRs). The columns study was conducted with two duplicate reactors (operated in parallel) that underwent separate perturbations of breathing air introduction. Aqueous samples were collected in 160 mL microcosm bottles and analyzed on a GC equipped with a Flame …

Degradation And Inhibition Of Chlorinated Ethanes And Ethenes In A Two Bed, Sequential Bioremediation System, Alex Boudreau

LSU Master's Theses

A continuous-flow system composed of two anaerobic bioreactor (ABR) columns (based on engineered wetland systems) connected in series was tested to observe the ability of such a system to treat multiple volatile organic compounds (VOCs) possessing suspected inhibitory effects on the dechlorination of other compounds with cis-1,2-dichloroethylene (cDCE) and 1,1-dichloroethane (1,1-DCA) as the main test chemicals. Following the establishment of cDCE and 1,1-DCA dechlorinating ability at baseline conditions, system perturbations of breakthrough and starvation were conducted to measure the response and recovery of the system dechlorination. In all column experiments, it was observed cDCE dechlorination inhibited the dechlorination of 1,1-DCA …

Enhanced Bioremediation Of 1,1,2,2-Tetrachloroethane In Wetland Soils, Jason S. House

LSU Master's Theses

This research investigated the capability of wetland soils to function as a medium for the degradation of 1,1,2,2-TeCA and its daughter products, and the influence of different hydrogen donors and nutrients on this process. The rate constants calculated for this study, show that removal of 1,1,2,2-TeCA is occurring in the microcosms receiving hydrogen donors as well as the biotic controls. The parent compound was undergoing complete degradation to ethene, which was confirmed by ethene analysis, as well as monitoring the intermediate compounds. The analysis for the degradation products of 1,1,2,2-tetrachloroethene is important in determining the overall potential for successful degradation …