Groundwater resources have become seriously threatened
due to improper use by industrial, municipal, and even public
sectors. Widespread contamination of aquifer systems has
jeopardized human health and the environment and methods for
restoring these systems are needed. Biological and chemical
in situ remediation, where contaminants are degraded within
the natural...
This research focused on the enhanced reductive dechlorination of trichloroethene (TCE) and its surrogate, trichlorofluoroethene (TCFE), using two bioremediation methods in anaerobic conditions. Two anaerobic bioremediation studies were conducted to investigate the effects of microbial communities in the presence of different electron acceptors and donors during anaerobic reductive dechlorination of...
A pilot scale demonstration of a biological permeable barrier was conducted in a pentachlorophenol-contaminated aquifer at a wood preserving facility. A permeable reactor was constructed to fit within a
large diameter well. Arranged in series, a cylindrical reactor 24" x 36" (0.61 x 0.91m) (diameter x height)
was partitioned to...
In situ bioremediation of pentachlorophenol-contaminated ground water in a sequential anaerobic-aerobic down borehole permeable barrier reactor requires a non-toxic primary substrate for dichlorophenol cometabolism. Serum bottle tests comparing the effectiveness of eight primary substrates for aerobic dichlorophenol degradation showed phenol to be the most effective followed by imitation vanilla flavoring,...
Groundwater at Oak Ridge National Laboratory's Field Research Center (FRC) is contaminated with U(VI) and Tc(VII), has pH values as low as 3.3, and nitrate concentrations as high as 120 mM. The objective of this research was to determine if in-situ bio-immobilization is a viable treatment alternative for this water....
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...
At Site-300, Lawrence Livermore National Laboratory (LLNL), CA,
trichloroethene (TCE) is present along with tetraalkoxysilanes such as tetrabutoxysilane
(TBOS) and tetrakis(2-ethylbutoxy) silane (TKEBS), as subsurface contaminants.
Intrinsic transformation of TCE to cis-dichloroethene (c-DCE) was observed in the
groundwater at locations co-contaminated with TBOS or TKEBS. Attenuation of TBOS
and TKEBS...
Aquifers are an important storage location and source of fresh groundwater. They may become polluted by a number of contaminants including mobile divalent radionuclides such as strontium-90 which is a byproduct of uranium fission. A method for remediating such divalent radionuclides is sequestration through co-precipitation into calcium carbonate. Calcium carbonate...
Chlorinated aliphatic hydrocarbons (CAHs) such as vinyl chloride (VC) and 1,-2 dichioroethane (DCA), are wide-spread groundwater pollutants found at many contaminated field sites around the world. Quantitative tools are needed to determine the in situ rates of VC and DCA transformation to ethene in contaminated groundwater. The objective of this...
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...
Halogenated organic compounds have had widespread and massive applications in industry, agriculture, and private households, for example, as degreasing solvents, flame retardants and in polymer production. They are released to the environment through both anthropogenic and natural sources. The most common chlorinated solvents present as contaminants include tetrachloroethene (PCE, perchloroethene)...
Batch microcosm studies were carried out to screen for microorganisms from the
subsurface of Hanford DOE site that could cometabolically transform chloroform (CF)
under aerobic conditions. The potential need for CF bioremediation at the Hanford site
has resulted from the large release of carbon tetrachloride (CT) to the subsurface, of...
Metal and hydrogen ion acidity and extreme nitrate concentrations typical of
Department of Energy (DOE) legacy waste sites pose formidable challenges to
successful implementation of in situ bio-immobilization. Intermediate-scale (~ 2.5 m),
flow through models of an in situ bio-barrier were constructed to investigate U and Tc
removal from groundwater...
Iodine-129 is a key risk driver at sites where nuclear materials have been fabricated or processed, and it is a predominant isotope of concern in long-term waste storage strategies. I-129 exists primarily as iodate in the subsurface at the Hanford Site in south-central Washington State. Between 15 and 40% of...
Linear alkylbenzenesulfonate (LAS) is the most widely used anionic surfactant in
commercial detergent formulations. The environmental fate of LAS is of interest because
of its disposal to wastewater treatment facilities and subsequent occurrence as a
micropollutant in surface waters and groundwater. While LAS fate in wastewater
treatment systems and surface...