Although surface water constitutes less than 1.5% of freshwater supply, historical development of surface water sources continues to mark the landscape. However, over- exploitation of groundwater is now at its highest, and 25% of the world’s 1.7 billion population live in water scare regions. As glaciers and snowpack disappear due...
Enzymes play an important role in the environment, they breakdown natural-occurring and anthropogenic molecules so that they can be transported into cells and utilized. Enzyme assays are routinely used in soil science and oceanography to measure the activities of specific processes and to serve as general indicators of microbial activity....
The objective of this study was to develop a numerical model for the movement
and fate of chlorinated phenols in groundwater. In the first part, a numerical model for
several different equilibrium and nonequilibrium sorption processes under isothermal
conditions is developed for one-dimensional, steady-state water flow in soil columns.
The...
A thermodynamic analysis of forced geoheat recovery from aquifers
has been accomplished. The system investigated consists of a single
recharging-discharging well pair, in a horizontally extensive aquifer,
with either power generation or space heating as surface applications.
The space heating systems investigated are (i)direct heating, (ii)heat
pumps and (iii)a combination...
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...
Trichloroethene (TCE) is the most frequently detected organic contaminant in groundwater, is classified as a probable human carcinogen, and exhibits toxicological effects on the human endocrine, immune, developmental, and reproductive systems. While significant research efforts have been devoted to the development of strategies for remediating TCE-contaminated groundwater, their advancement is...
The present work is a study of three degenerate, linear parabolic
systems of equations, each of which represents a version of the so-called
double porosity model for underground fluid flows in natural fractured
rock. These systems of equations together with initial and boundary
conditions describe single-phase flows in fluids, slightly...
Stream discharge is a key water balance component and important factor in global change evaluations. Nevertheless, the mechanisms for streamflow generation are poorly understood. Near- stream surface saturation during precipitation events is one of the most iconic, visible indicators of rapid runoff production in upland humid catchments around the world....
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...
Contaminant transport in ground water is an important environmental process that
affects a host of natural systems. Transport of contaminants is affected by many
processes, including aqueous complexation, adsorption, and redox reactions. One of the
most important components of an aquifer that controls transport is iron-oxide. In this
study, the...
The mixed metal compound, Chromated Copper Arsenate, or CCA, has been widely used as a wood preservative. The metal ions in CCA, CrO²⁻₄, Cu²⁺, and AsO³⁻₄, have been found in contaminated surface and subsurface soils and groundwater nearby some wood preservative facilities and nearby wood structures. Iron oxides are a...
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...
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...
Increases in food demand, favorable commodity markets and drive towards increasing productivity at a greater economic efficiency have accelerated negative agricultural
externalities, particularly erosion and water quality. The potential impact of these externalities on environmental quality and human health prompted an examination of current and potential production strategies on four...
With 97% of the world’s freshwater resources stored underground, the connection between groundwater resources to the metrics of space, scale and time common to the geographic study of natural resources has not been extensively investigated by geographers. While nearly 240 transboundary aquifers are mapped across the world, a potential “tragedy”...
Fault zones are potential paths for release of radioactive nuclides from radioactive-waste repositories in granitic rock. This research considers detailed maps of en echelon fault zones at two sites in southern Sweden, as a basis for analyses of how their internal geometry can influence groundwater flow and transport of radioactive...
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...