CisCis-Dichloroethylene (ciscis-DCE), 1,1,1-Trichloroethane (1,1,1-TCA), and 1,4-Dioxane (1,4-D) are chlorinated solvents used as solvents and degreasers in industrial cleaning agents that have become common groundwater contaminants. To develop an effective treatment method for these compounds, polyvinyl alcohol (PVA) and sodium alginate (SA) hydrogel beads were co-entrappcapsulated with Rhodococcus rhodochrous Strain ATCC...
Chlorinated aliphatic hydrocarbons (CAHs) like trichloroethene (TCE) were mostly used to replace drying cleaning fluids which contained hydrocarbons like benzene, and were highly flammable. Through improper disposal, storage, and spills, TCE and its downstream products, like cis-dichloroethene (cDCE) and vinyl chloride (VC), leached into groundwater and threaten human and environmental...
Methods were developed for the co-encapsulation of slow release compounds (SRC) with viable microbial cells in alginate and gellan gum hydrogel beads, for the in-situ aerobic cometabolic treatment of groundwater contaminated with mixtures of 1,4-dioxane and chlorinated aliphatic hydrocarbons, which will be referred to as contaminants of concern (CoC). The...
The transformation of 1,1,1 -trichioroethane (1,1,1 -TCA) and 1,1 -dichioroethene (1,1 -
DCE) was evaluated in a continuous flow column reactor using a mixed culture that grew
on butane. The column was packed with aquifer materials and groundwater obtained
from the in-situ bioremediation test site at Moffett Field, CA. The...
The aerobic transformation of TCE and cis-DCE by a tetrabutoxysilane-grown microorganism (Vancheeswaran et al., 1999) led to the investigation of novel substrates, including benzyl alcohol, for promoting cometabolism. The culture grew on carboxylic compounds and alcohols, but did not grow on formate, methanol, methane, propane, butane, ethylene, benzene, toluene, or...
Laboratory scale microcosm studies were conducted using site specific groundwater and aquifer solids to assess the feasibility of stimulating indigenous microorganisms in-situ to biologically transform Trichloroethylene (TCE) and its lesser chlorinated daughter products dichloroethylene (DCE) and vinyl chloride (VC). Three different treatments were conducted to determine the best approach for...
Chlorinated solvents are common groundwater pollutants that often exist as mixtures resulting from the use of multiple solvents and their transformation into chlorinated daughter products. These sites are often co-contaminated with the solvent stabilizer 1,4-dioxane (1,4-D), which is not treated by traditional chlorinated solvent remediation techniques. Both 1,4-D and chlorinated...
Laboratory and modeling studies were performed with a mixed-anaerobic-culture obtained from the Evanite site in Corvallis, Oregon. The culture completely transforms trichloroethene (TCE) to cis-dichloroethene (c-DCE), vinyl chloride (VC), and finally to ethene. Acetylene inhibition studies were used to examine the culture's microbial activities. Kinetic studies determined the half-saturated constant...
A mix-culture of methanogenic and sulfate-reducing bacteria was capable of degrading trichloroethylene (TCE) to dichloroethylene (DCE). The culture was incubated under anaerobic conditions within a soil sample taken from Gilbert-Mosley site, Wichita, Kansas. To stimulate the growth of indigenous bacteria, a carbon and energy source was added in this microcosm...
This research focused on anaerobic transformation of trichloroethene (TCE), a
groundwater contaminant. The mixed anaerobic Evanite culture (EV) was studied to determine community behavior and composition responses to different electron donors and chloroethene electron acceptors. The potential toxicity from high concentrations of TCE and its daughter product cis-1,2-dichloroethene (cDCE) was...
This study investigated complete reductive dechlorination of chlorinated aliphatic hydrocarbons (CAHs) over a broad range of concentrations. Tetrabutoxysilane (TBOS), as a slow-release anaerobic substrate, was studied for enhanced reductive dechlorination of tetrachioroethylene (PCE) present as a dense non-aqueous liquid (DNAPL). Four different site-mixed cultures were used in the study: Site-300...
This study investigated the use of radon-222 as an in situ partitioning tracer for quantifying nonaqueous phase liquid (NAPL) saturations in the subsurface. Laboratory physical aquifer models (PAMs), field experiments, and numerical simulations were used to investigate radon partitioning in static (no-flow) experiments and in single-well, 'push-pull' tests conducted in...
Carbon tetrachloride (CT) and chloroform (CF) were transformed in batch reactor experiments conducted with anaerobic dechlorinating cultures and supernatant (ADC+S) harvested from continuous flow reactors. The Evanite (EV-5L) and Victoria/Stanford (VS-5L) cultures capable of respiring trichloroethene (TCE), 1,2-cis-dichloroethene (cDCE), and vinyl chloride (VC) to ethene (ETH) were grown in continuous...
The inhibitory effects of Corexit 9500A, Alaska North Slope Crude oil (ANSC), and mixtures of the two on the ammonia-oxidizing bacteria, Nitrosomonas europaea, and the ammonia-oxidizing archaea, Nitrosopumilus maritimus, were investigated. Corexit 9500A was found to be minimally toxic to both microorganisms with concentrations of 2000 and 3000 ppm yielding...
The cometabolic ability of Burkholderia vietnamiensis G4 grown on aromatic substrates was first assessed by resting suspended cells, and subsequently for cells encapsulated with and without slow release compounds (SRCs). In Chapter 3, benzyl alcohol was assessed as a food-grade growth substrate for promoting cometabolism of trichloroethene (TCE), via the...
1,4-dioxane and chlorinated aliphatic hydrocarbons (CAHs) such as trichloroethylene (TCE) and 1,1-dichloroethene (1,1-DCE) are hazardous compounds commonly found in soil and groundwater. Bioremediation through aerobic cometabolism is a potential option for the remediation of these contaminated sites. The purpose of this study was to examine the use of different primary...
Ammonia oxidizing bacteria, including Nitrosomonas europaea, are inhibited by aromatic hydrocarbons which can be found in wastewater treatment plants. In recent studies, changes have been observed in N. europaea cell size upon exposure to benzene, but not toluene. Additionally, NE 1545, a gene proposed to be involved in fatty acid...
Radon-222 gas has unique properties allowing it to be used as an indicator for the
presence of organic phase liquids in the saturated zone. It naturally occurs in soils. It is
radioactive, making quantitative detection straight forward. A noble gas, it is chemically
inert and does not react with aquifer...