A water balance study was conducted at an agricultural and a pristine site on the Konza Prairie research area. The hydrologic variables of interest were precipitation, surface runoff, evapotranspiration, infiltration and soil water content. Surface infiltration properties were measured at 40 locations over each site. Spatial variability of these properties was incorporated into compution of areally averaged infiltration rates. The water budget model was used to predict average soil water contents. These were compared with measured values for model evaluation.
Keyword(s): infiltration, spatial variability.
Poster presentation.
The use of vegetation at waste sites is a
logical approach to improving microbial
degradation of xenobiotics by overcoming
some of the inherent limitations to biological
cleanup approaches such as low microbial
populations or inadequate microbial activity.
Plants are known to influence soil
microorganisms in positive ways by exuding
organic substances into the root zone and
providing a microhabitat conducive to
proliferation. Previous research has
demonstrated that rhizosphere soils or
microorganisms isolated from rhizosphere
soils often exhibit accelerated rates of
xenobiotic metabolism, suggesting that
plants might be valuable as a cost-effective
approach for biological remediation of waste
sites.
An area where cost-effective approaches to
remediation are in particular need is retail
agrochemical dealer sites. Many of these
dealerships have experienced soil and water
contamination problems from normal
operating procedures and accidents during
the last 40 years. In most instances, the
costs associated with current cleanup
technologies preclude their use at these
facilities.
A potential limitation to using vegetation
exists at these sites because of the
presence of mixtures of herbicide
contaminants at concentrations several-fold
above the field application rate. Nonetheless,
herbicide-tolerant and herbicide-resistant
plants, including kochia (Kochia scoparia),
barnyardgrass (Echinochloa crus-galli) and
pigweed (Amaranthus retroflexus) routinely
inhabit these environments. Previously, we
demonstrated that the degradation of
atrazine, metolachlor and trifluralin was
significantly greater in rhizosphere soils
from Kochia scoparia than in nonvegetated
soils. In addition, mineralization of 14C-
atrazine in a mixture of atrazine and
metolachlor (50 mg/g each) was significantly
greater in Kochia scoparia rhizosphere soils
than nonvegetated soils. In both studies,
soils were collected from retail
agrochemical dealer sites where mixtures of
herbicides were present in the soil at
concentrations several-fold above the field
application rate. In addition, rhizosphere
soils from other plant species were tested
for their ability to mineralize atrazine or
metolachlor at concentrations typical of
point-source contamination (50 mg/g).
Several rhizosphere soils tested positive for
14C-atrazine mineralization (³ 8.5%)
including lambsquarters (Chenopodium
berlandieri), foxtail barley (Hordeum
jubatum), witchgrass (Panicum capillare),
catnip (Nepeta cataria) and musk thistle
(Carduus nutans). These results suggest
that plants might be managed at pesticide-
contaminated sites to help facilitate
microbial degradation of wastes in soils.
Keyword(s): rhizosphere, bioremediation, atrazine, vegetation.
Poster presentation.
Soil hydraulic properties are needed for
modeling water movement in soils. Past
attempts at relating hydraulic properties to
easily measurable quantities like pore size
distribution have relied on empirical and
semi-empirical relationships. This study
proposes to use Artificial Neural Networks
(ANNs) for predicting soil hydraulic
properties (hydraulic conductivity, saturated
water content and the alpha parameter of
Gardner's relationship) from percentages of
sand, silt and clay and bulks density of the
soil. The backpropagation algorithm is used
for this purpose. The performance of ANNs
will be compared with some existing
models.
Keyword(s): soil hydraulic properties, particle size distribution, neural networks, backpropagation algorithm.
Oral presentation in environmental assessment and
decision making session.
The presence of vegetation has been
demonstrated to increase the
biodegradation of several classes of organic
compounds. Polycyclic aromatic
hydrocarbons (PAHs) are highly recalcitrant
and hydrophobic contaminants. Once
incorporated into the soil, biodegradation
seems to be the most effective means of
remediation. Laboratory experiments were
conducted to evaluate the mineralization of
PAHs (pyrene and phenanthrene) in the
rhizosphere due to cometabolism and
assess their fate in the rhizosphere of
several species of grasses and legumes.
The mechanism of cometabolism was
tested by adding phenanthrene to soil
containing 14C-pyrene. The cometabolic
environment induced due to phenanthrene
resulted in an increased generation of 14CO2
especially in the rhizosphere soil with
organic acids. The dissipation of 14C-
phenanthrene in various rhizosphere soils
was assessed for mineralization,
volatilization and residual 14C in soil.
Mineralization was significantly greater in the
warm season grasses, sorghum (Sorghum
bicolor L.), bermuda grass (Cynodon
dactylon L.) and the legume soybean
(Glycene max L.) compared to soil from
alfalfa (Medicago sativa L.) which did not
differ from control soil. It was found that a
large portion of the biodegraded 14C-
phenanthrene was incorporated into soil
organic matter either as microbial biomass
or degradation products.
Keyword(s): biodegradation, PAH, rhizosphere, cometabolism.
Poster presentation.
A common environmental problem
associated with the pumping and refining of
crude oil is contamination of soil with
petroleum products. Vegetation may play an
important role in the biodegradation of
petroleum contaminants in soil. The
establishment of vegetation may be an
economical, effective, low maintenance
approach to remediation and stabilization.
The use of plants for remediation may be
especially well-suited for soils contaminated
to depths of less than 2 meters.
In this project, several petroleum
contaminated field sites have been chosen
in collaboration with industrial partners.
These sites have been thoroughly
characterized for chemical properties,
physical properties and initial TPH
concentrations. A variety of plant species
have been established on two of the sites.
Soil analyses for target compounds over
time will be reported. Results from this study
will allow us to assess the efficiency and
applicability of this remediation method.
Keyword(s): bioremediation, vegetation, petroleum, biodegradation, rhizosphere.
Poster presentation.
The design of a “washing” process for the
removal and recovery of toxic metals from
contaminated soil requires in-depth
knowledge of the speciation of the metals. In
addition to being present in their original
forms (e.g. oxides particulates emitted by a
smelter), the contaminating metals may
come to be associated with a variety of solid
phases commonly present in the soil. A
sequential chemical extraction procedure
has been used to characterize lead and
cadmium speciation in soil collected in the
vicinity of a zinc smelter that was in
operation for 70 years.
Keyword(s): soil, lead, cadmium, speciation.
Poster presentation.
The Waste-Management Education and
Research Consortium (WERC) was formed
four years ago for the purpose of developing
human and technological resources that can
address issues related to the environment
and the management of waste. For the past
four years, WERC has supported
development of innovative technologies
proposed by researchers from the
academic institutions, in partnership with
researchers from national laboratories and
industrial partners. Researchers from four
universities in New Mexico have teamed with
Sandia National Laboratories, Los Alamos
National Laboratory and industrial partners
to develop over 50 advanced technologies.
Several of these have moved to field
application. One such project is the
development of a unique system that
detects and provides a 3-D display of buried
waste from sites. This system is now in the
commercial stage and assists industrial and
national laboratories such that remediation
can proceed in a safe and economical
manner. Another project involves application
of bioremediation and other chemical
techniques to the Uranium Mill Tailings
Remediation Act project of the U.S.
Department of Energy (DOE). A third project
in partnership is a Petroleum Organizational
in the process of application of a technique
using tailored zeolites to absorb organic
contaminance from ground water. This
system is under application at refinery and
production operations. Another major
application uses advanced monitoring
technologies to totally monitor the soil, air,
water, humans, flora and fauna around a
nuclear repository.
These are just examples of some of the
technologies developed by the partnership.
We have gone beyond the theoretical or the
laboratory stages and are now at
applications stages contributing to the safety
and cleanup of our environment at
government and industrial sites. In addition
to the technological impact, these are
making a real contribution to the education
of students who are involved in the
development. Students gain real life
experience which can assist them in their
careers as environmental professionals.
This paper will describe advanced
technologicies as well as the system that
has led to the successful application of
technologies.
Keyword(s): remediation, site applications, advanced technologies.
Oral presentation in technology transfer session.
Poor waste management practices at
munitions production facilities have
contaminated surrounding soil and water
with hazardous materials, particularly TNT
(2,4,6-trinitrotoluene) and cyclonite (RDX,
hexahydro-1,3,5-trinitro-1,3,5-triazine).
Remediating these contaminated sites is
necessary to ensure public safety. Soil
cleanup by the conventional technique of
incineration, however, is very expensive and
often unacceptable to the public. Cost-
effective and environmentally acceptable
remediation treatments are needed. We
determined the efficiency of an abiotic
oxidative treatment (Fenton oxidation) and a
reduction treatment (metal reduction) for
remediating RDX-contaminated soil.
Oxidation experiments evaluated the effects
of H2O2, Fe2+, and initial RDX
concentrations, UV light, and contaminated
soil extracts on rates of RDX transformation
and mineralization. Treating an aqueous
solution of 20 mg 14C-RDX L-1 in the dark
with Fenton reagent (1% H202 and 80 mg
Fe2+ L-1) resulted in complete removal of
RDX within 24 h. This coincided with 70 to
85% RDX mineralization. Similar results
were found with aqueous extracts of RDX-
contaminated soil. UV light enhanced both
RDX transformation and mineralization
rates. The metal reduction experiments
were performed with elemental Zn or Fe in
aqueous solutions of RDX, contaminated
soil extracts and soil-slurries. Treating 40
mg L-1 14C-RDX with Zn (5:1 solution:metal
ratio) resulted in complete destruction of
RDX within 2 h. Higher transformation rates
were generally observed at lower pH. Iron
was also effective in reducing RDX in
solution. Mineralization of RDX by Zn
reduction was not observed. The metal
reduction treatment was also effective in
removing RDX from contaminated-soil
extracts and soil-slurries. These results
indicate that both abiotic oxidative and
reductive treatments can effectively
remediate RDX-contaminated soil and
water.
Keyword(s): munitions, RDX, cyclonite, Fenton oxidation, remediation, metal reduction.
Poster presentation.
By virtue of their large surface area and high
sorption potential, fine clay particles adsorb
significant quantities of subsurface
contaminants and may be considered
particulate contaminants. Understanding the
mobility of these particulate contaminants in
porous media is essential to predict the
contaminant transport in ground water. In a
geoenvironmental engineering context, the
mobility of the fine particles has recently
been viewed as desirable in subsurface
remediation. The stability of these particles
depends on both physical and chemical
effects induced through pore water flow. The
combined effect of dynamics and
composition of pore fluid may significantly
alter the permeability and transport
characteristics of the porous media. In this
study, various hydraulic gradients were
considered in a theoretical analysis to
account for the effect of pore fluid dynamics
on the mobility of the contaminants. Pore
fluid characteristics such as ionic strength
and valency were considered in the analysis
by accounting for London-van der Walls
attractive forces and electrical double-layer
attractive or repulsive forces. The study
addresses the interaction of forces at a
microscopic level acting on individual
clusters of particles to assess the
significance of the two effects. Finally, the
significance of the fine particle stability is
assessed in light of the standard transport
mechanisms (advection and diffusion).
Keyword(s): particulate contaminants, pore fluid, permeability, porous media, transport mechanism.
Oral presentation in fate and transport session.
An investigation of the chemical composition
of mining and smelter wastes and the
composition's effect on the bioavailability of
lead, as predicted by geochemical modeling,
will be presented. Chemical sequential
extraction was used to quantify the different
types of chemical bonding in the samples.
X-ray analysis of the samples and their
sand, silt and clay fractions was also
performed. The results from these
laboratory investigations were compared
with geochemical modeling. Modeling
predictions and laboratory results were
similar.
Keyword(s): mining wastes, characterization, sequential extraction.
Oral presentation in heavy metals session.
New fuels and pollution solutions can be
realized with cells on rotating fibers. Fibers
have high area and when Celite is entrapped
in the fibers, even more area is provided.
Zymomonas can ferment glucose to ethanol
in 15 minutes, and a recombinant version
can ferment pentose sugars.
Zymomonas on Tyvek fiber removes lead
from wastewater in two seconds. Some
people think all bacteria are poisonous, but
in Brazil scientists have found it to be
therapeutic. Dried grain from a Zymomonas
fermentation is generally recognized as safe
(GRAS) for animal feed. Several large cities
are over the limit for lead in drinking water.
Other metals can be removed also.
Calcium magnesium acetate, a non-
corrosive road deicer is made with cells on
rotating fibers. Salt causes millions of
dollars damage to roads and bridges.
Inexpensive raw material such as cheese
whey and corn steep liquor can be used.
When a rotary biological contactor is run half
full and a light shone in the top, the light hits
a thin moving film. In other photo reactors,
colored solution blocks the light. Light can
degrade chlorine compounds and produce
hydrogen, a non-polluting fuel. Rapid
increase of CO2 threatens the very
existence of mankind. Titania entrapped in
the fiber increases the rate of the reaction. In
a horizontal RBC, hydrogen has an easy
exit, just like CO2 has an easy exit when
fermenting sugar to alcohol.
White rot fungus grows on fibers like old
cardboard boxes to degrade chlorine
compounds, azo dyes and TNT. The
corrugations entrap air which is necessary
for growth of the fungi when buried in soil.
Keyword(s): ethanol, lead, deicer, hydrogen.
Poster presentation.
The investigation of past operational and
disposal practices at federal facilities and
formerly used defense sites (FUDS) has
dramatically increased in the past several
years. The manufacture, load, assembly
and pack (LAP), demilitarization, washout
operations, and open burn/open detonation
(OB/OD) of ordnance and explosives has
resulted in contamination of soils with
munitions residues. The primary
constituents are nitroaromatic and nitramine
organic compounds, and heavy metals. A
number of sites have soil contamination
remaining where waste disposal practices
were discontinued 20 to 50 years ago.
In conjunction with site investigations,
biological treatment studies have been
undertaken to evaluate the potential for full
scale remediation of organic contaminants.
This paper evaluates the results of 15
bioremediation treatability studies conducted
at eight sites for explosives contaminated
soils, and discusses the full scale remedial
implementation status. Five basic types of
biological treatment processes have been
evaluated, including: (1) composting, (2)
anaerobic bioslurry, (3) aerobic bioslurry, (4)
white rot fungus treatment, and (5) solid
phase treatment. Representative bench and
pilot scale studies were conducted using
site-specific munitions residues to
determine the ability to meet preliminary
remediation goals (PRGs) or cleanup levels,
and to identify issues related to scale-up of
the technologies.
Composting has been selected as the full
scale remedial action treatment remedy at
two National Priority List (NPL) sites: (1)
Umatilla Army Depot Activity, Hermiston,
Oregon, for 15,000 tons of soil contaminated
with TNT (2,4,6-trinitrotoluene), RDX
(hexahydro-1,3,5-trinitro-1,3,5-triazine) and
HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-
tetrazocine), and (2) U.S. Naval Submarine
Base, Bangor, Washington, for 2,200 tons of
TNT-contaminated soils. Pilot scale
composting treatability studies have
demonstrated the ability to achieve risk-
based cleanup levels of 30 to 33 parts per
million (ppm) for TNT and 9 to 30 ppm for
RDX after 40 days of treatment, with a
destruction and removal efficiency (DRE) of
greater than 99.0%. Feasibility Study (FS)
estimates of treatment costs range from
$206 to $766 per ton for quantities of 1,200
to 30,000 tons, 40% to 50% less than on-
site incineration. In the past, all NPL sites
with explosives contamination have used
incineration as the selected treatment
technology. Actual costs for biotreatment will
be refined during full scale remediation.
Keyword(s): explosives, munitions, ordnance, bioremediation, biological treatment.
Oral presentation in technology transfer session.
Disagreement often exists between
degradation rate constants obtained from
batch degradation experiments and leaching
experiments. Although degradation can be
quantified successfully in a batch-type
experiment, no satisfactory method exists
for this purpose in a leaching experiment,
apart from curve-fitting. During leaching, the
simultaneous occurrence of sorption,
dispersion and convection confounds the
duration for which true degradation takes
place within the soil. A correct description of
the true degradation opportunity time is
needed for computing the degradation rate
constant in this case. We have used
statistical moments to show that when
degradation follows first-order kinetics, the
time of degradation is an adjusted
convection time (ACT). It is defined as the
harmonic mean of m1/R and the convection
time (L/v), where m1 is the first moment, R
is the retardation factor, L is the length of
soil column, and v is the pore water velocity.
The adjustment in the convection time scale
is a direct result of both dispersion and
degradation occurring simultaneously in soil.
We show that these two processes tend to
slightly reduce the true convection time for
the leaching event. Therefore, the ACT is
smaller than L/v when both dispersion and
degradation occur. We have tested our
result by generating artificial breakthrough
curves with known first-order degradation
rate constants and then successfully
estimating the rate constant from the
breakthrough curve by using our approach.
We have outlined a detailed procedure to
estimate the degradation rate constant from
the information generated in a typical
leaching experiment.
Keyword(s): degradation, breakthrough curve, moment, travel time, convection time.
Poster presentation.
Chlorinated organic compounds are a
hazard to the environment and to humans.
Although many of these compounds are
generated by nature, there has been
concern about the effect of manmade
chlorinated compounds on the environment.
This recent concern has spurred research
investigating environmentally benign
disposal methods for these chemicals.
Previous research has shown that
nanometer sized calcium oxide particles are
effective in destroying some simple
compounds of hazardous concern. It has
also been shown that magnesium oxide will
also destroy some of these chemicals and
that iron coated magnesium oxide shows an
enhanced reactivity relative to uncoated
magnesium oxide. Typically the transition
metal loading is 1-5% of the molar amount
of the magnesium oxide substrate.
The purpose of the current research is to
see if the same enhanced reactivity occurs
with CaO particles which are less expensive
to manufacture. This research investigates
the effect of nickel, copper and zinc coatings
on the ability of calcium oxide particles to
destructively adsorb carbon tetrachloride.
Carbon tetrachloride was chosen as a
model compound because its reaction with
CaO is simple and easy to monitor. The
products of the reaction are simply calcium
chloride and carbon dioxide.
Preliminary results show that nickel coated
calcium oxide has an enhanced reactivity
relative to uncoated calcium oxide. It has
also been observed that the particles may
exhibit a “catalytic” reactivity rather than
stoichiometric and, therefore, may be
extremely useful in the degradation of
harmful chlorinated organic compounds.
Keyword(s): destructive adsorption, chlorinated organics.
Oral presentation in chemical destruction session.
This research was undertaken to simplify
the selection of the least-cost treatment
option for treating waters contaminated with
synthetic organic chemicals (SOCs). Five
aqueous treatment processes were
considered: air stripping, liquid-phase
adsorption, steam stripping, biofilm reactor,
and combined biodegradation and
adsorption (bio-adsorption). Because off
gases from air stripping towers are
frequently regulated, four off-gas treatment
processes also were considered: gas-
phase adsorption (both on- and off-site
regeneration), thermal incineration and
catalytic oxidation. Mathematical process
performance and cost models were
developed for each process. The least-cost
design for each process was identified for a
set of typical contaminated waters, and the
results were synthesized to create
generalizations concerning process
selection based on fundamental process
variables.
For example, the cost of treating air stripper
off gases was found to be primarily a
function of a compound's adsorbability,
volatility, flow rate and influent concentration.
A set of diagrams was created to identify the
least-cost off-gas treatment for a given set
of conditions.
For aqueous processes, the least-cost air
stripping tower design changed when off-
gas treatment was added. A methodology
for comparing the costs of air stripping with
off-gas treatment and liquid-phase
adsorption was created in the form of a
process selection diagram. The comparison
methodology is based upon physical
parameters of the target chemical.
In considering bio-adsorption, it offered
longer bed lives than adsorption alone in
nearly every case, though the degree of
improvement varies. Diagrams were
created to identify cases where bio-
adsorption is particularly economical.
Situations were identified where a biofilm
reactor and where steam stripping may be
economically viable. Heuristics concerning
when processes-in-series are valuable were
also developed. As discussed, tools and
generalizations were created to aid
engineers in making intelligent decisions
concerning preliminary treatment process
selection, with the overall goal of better,
cost-effective designs and more rapid
selection.
Keyword(s): organic chemicals, treatment, remediation, heuristics.
Oral presentation in environmental assessment and
decision making session.
The practical application of chemical
analyses begins with a request for the
analysis and concludes with provision of the
requested analytical data. The key to
successful execution of this activity is
timely, professional communication between
the requester and the analyst. Often
chemical analyses are not satisfactorily
executed, either because the requester
failed to give adequate instructions or
because the analyst simply “did what he/she
was told.” The request for and the conduct
of an analysis represent a contract for the
procurement of a product (information about
the sample); if both parties recognize and
abide by this contractual relationship, the
process generally proceeds smoothly. Note
that the “customer” and “analyst” may be the
same person, especially in a university
research environment; these same issues
hold even in this single-person interaction.
Chemical analysis is traditionally defined as
the determination of what is in the sample
and how much of that constituent is present.
More rigorously, we also need to know if the
analysis was conducted correctly and we
need documentation. In short, we need
quality control. Before a chemical analysis
begins, it is important to establish the data
quality objectives: What are we looking for,
and how much error can we tolerate?
This presentation will provide a practical
tutorial on how to get chemical analyses
done properly and cost-effectively.
Suggestions will be provided for improving
the quality of the analytical product through
the requester-analyst interface.
This work was supported by the U.S. Department of
Energy, Assistant Secretary for Environmental
Management, under contract W-31-l09-Eng-38.
The submitted manuscript has been authored by a
contractor of the U.S. Government under contract No. W-
31-109-ENG-35. Accordingly, the U.S. Government retains
a nonexclusive, royalty-free license to publish or reproduce
the published form of this contribution, or allow others to do
so, for U.S. Government purposes.
Keyword(s): chemical analysis, analysis.
Oral presentation in conducting HSRC research
session.
Various technologies are currently being
investigated to remediate aquifers
contaminated with organic chemicals that
are in the from of non-aqueous phase liquids
(NAPLs). After a spill, NAPLs remain
entrapped in the soil for long periods of time,
thus acting as a source of contamination.
The possible use of surfactants as a way of
enhancing dissolution and thus depleting the
source is under study. In our ongoing
research we have demonstrated the
importance of heterogeneity in the transport
and entrapment distribution of NAPLs in
aquifers. We have identified two modes of
entrapment, namely microscale entrapment
at the pore scale and macro-scale
entrapment that is produced by the larger
heterogeneities of the aquifer. We have
investigated the effects of relative
permeability and dimensionality on the
dissolution of these chemicals, both under
micro- and macroscale entrapment. This
paper presents the results from a study
where we have investigated the process of
enhance dissolution under macro- and
microscale entrapment. These results will
be used to develop and validate models that
can be used to design and evaluate field
remediation schemes that use surfactants.
A series of two-dimensional experiments
were conducted to investigate the
dissolution of non-aqueous phase liquids
(NAPLs). Experiments were conducted for
NAPLs at both residual saturations and
under macroscale entrapment conditions.
Aqueous phase samples were collected
downgradient of the source, and the
dissolved NAPL concentrations were
measured by gas chromatography. The
breakthrough curves were analyzed to
determine the overall mass transfer
coefficients. The mass transfer coefficients
were used to investigate the effects of
entrapment saturations and the
dimensionality of flow on enhanced
dissolution. The experimental design, results
and data analysis are presented.
Conclusions on the use of these results for
the design of large pilot-scale, enhanced-
dissolution experiments to study scale
effects are presented.
Keyword(s): ground water, NAPL, dissolution, surfactants, heterogeneities.
Oral presentation in non-aqueous phase liquids session.
Scrap tires represent a major environmental
problem. It is estimated that approximately
2.5 million tons of scrap tires are generated
each year in North America. Most of these
materials are discarded and have found little
use through reclamation. The reclaimed
rubber and other materials are not suitable
for production of tires or other durable
rubber goods. As a result, most of the scrap
tires accumulate in dumps and create
hazards for infestation, water pollution and
fire.
Automobile tires are composed of carbon
black reinforced rubber. Typical composition
of tires is 62% styrene butadiene copolymer
rubber, 31% carbon black, and other
materials, such as extender oils, sulfur, zinc
oxide and stearic acid, which are present in
smaller amounts. Potential reuse of the
polymeric contents of tires has received
considerable attention. Processes have
been evaluated for production of goods such
as construction fillers; however, fillers and
other reclamation applications have shown
relatively small economic potential. Another
process of interest is the pyrolysis of tires to
produce liquid hydrocarbons and gases with
high calorific values. Pyrolysis yields solid
char residues which generally contain higher
amounts of elemental carbon than the
original tires. Most studies on conversion of
tire char to activated carbon rely on further
pyrolysis at 600-850 C under nitrogen
atmosphere followed by activation with acid
for reaction with superheated steam. All of
the processes are energy intensive.
An alternative low energy conversion
process has been evaluated in our
laboratory. The process is based on a
counterflow oxidative technique. The
technique utilizes a flame front which
propagates in a direction counter to the
oxygen flow. The results obtained show that,
under optimal conditions, the process yields
carbon with adsorptive characteristic similar
to those of commercially available activated
carbons. Breakthrough curves for toluene,
phenol and aniline were found to be
comparable to those obtained with
commercial carbons. Similarly, comparable
adsorptive capacities were obtained for
polychlorinated biphenyls (PCBs) in mineral
oils.
One of the major concerns for scrap tire
derived carbon is the presence of leachable
materials. Initial results of the U.S. EPA
extraction procedure and soxhlet extraction
are very encouraging and show that the
material is essentially free of leachable
chemicals.
Keyword(s): scrap tires, carbon, counterflow oxidation.
Oral presentation in pollution prevention/waste minimization.
Ground water is an important source of
water for much of the United States.
Contamination from agricultural pesticides
presents a serious problem. Fluctuating
water tables may increase microbial
degradation of these contaminants by: (1)
optimization of moisture content, (2)
increased transport of the contaminant to
the microbes, and (3) increased transport of
soil organic matter to the area. This
research is investigating the effects of a
fluctuating water table on microbial
degradation of pesticides. Multiple soil
columns are being used in this experiment.
We expect to observe increased pesticide
degradation with a fluctuating water table.
Keyword(s): pesticide, microorganism, degradation.
Poster presentation.
The performance of the in-well air sparging
process has been examined for cleaning up
a site contaminated with a mixture of non-
aqueous phase liquids (NAPLs). The
process remediates in situ a contaminated
aquifer by combining chemical, physical and
biological processes. A blower at the top of
the well induces upward motion of air and
water in the well, thereby creating a
circulatory flow pattern in the aquifer. The
flow of water in the aquifer has been
modeled as a potential flow between the
sources and sinks.
Biodegradation may be enhanced by
installing a packed-bed bioreactor within the
well casing. Since oxygen-enriched water
flows out of the bioreactor into the aquifer at
the upper screened segment of the well,
biodegradation is also enhanced in the
aquifer. The results of simulation
demonstrate that the compositions of the
NAPLs in the aquifer vary with time and that
the size of the packed-bed bioreactor
influences the pathway through which the
contaminants are removed from the aquifer.
As a general rule, however, biodegradation
plays a more dominant role in removing the
less soluble contaminants.
Keyword(s): aquifer, biodegradation, modeling, air sparging.
Oral presentation in non-aqueous phase liquids session.
Several different varieties of alfalfa plant
tissues were tested for their potential to
uptake copper ions from solution. Batch
experiments were performed to determine
the pH profiles, time dependency, capacity
of copper uptake, and desorption of the
metal bound. Also optimal drying conditions
(oven/lyophilized) as well as buffering
effects were examined. Differences in roots
and shoots were examined to determine the
uptake properties of seven alfalfa varieties
(germplasms). Protein analysis and crude
fiber content was determined for all
biomasses studied. Most of the biomasses
studied showed a high affinity for copper
ions as the pH increased from 2 to 6 with
optimum copper binding around pH 5.0.
Time dependency experiments for copper
binding showed a very rapid absorption of
the copper ions by the various alfalfa
species. Binding capacity experiments for
copper binding showed that the capacities of
the shoots is very similar, with african and
ladak germplasms being the highest.
Binding capacities for the roots also showed
to be similar with malone germplasm as the
highest. Overall, the shoots have higher
binding capacity than the roots. More than
90% recovery of the copper bound to the
various species by treatment with 0.1 M HCl.
This innovative technology has great
potential for the removal and recovery of
heavy metal ions from contaminated waters.
Keyword(s): bioremediation, alfalfa, Medicago sativa, copper, metal binding.
Oral presentation in phytoremediation session.
In this study, we used the Canadian
sphagnum peat moss, humic acid and
humin (extracted from the peat moss) to
investigate the copper binding properties of
the different biomasses. Batch pH profile
experiments indicated that the adsorption of
Cu was pH dependent. At pH 4.0 and pH
5.0, 99% of copper was bound by all three
samples (peat moss, humic acids and
humin) under our experimental conditions.
Time dependency and capacities of
adsorption showed that humic substances
extracted from sphagnum peat moss had
better metal binding properties. A high
percentage of the bound copper was
released by acid treatment. This
corroborates that humic substances coming
from peatland were an ideal media to adsorb
heavy metal ions from contaminated water.
It is believed that carboxyl groups are
primarily involved in copper ion binding.
Experiments are underway in our laboratory
to determine the possible role of carboxyl
groups in copper binding. These
experiments consist of chemical
modification of the carboxyl groups.
Description of these experiments will be
presented at the conference.
Keyword(s): sphagnum, peat moss, copper, uptake, humic substances.
Poster presentation.
Different varieties of Medicago sativa
(Alfalfa) were exposed to nickel
concentrations to determine their metal
binding capabilities. The Alfalfa samples
were divided into roots and shoots for
experimental purposes. Studies to
determine the pH profile for nickel binding
were conducted. These experiments
indicated that the metal binding to the
biomass was better between pH 5 and pH 6,
showing above 80% bound. We also
determined that between pH 2 and pH 3 the
binding of nickel was very low. This may
suggest that if the process is reversed
nickel could be recovered from the plant
cells. Time dependency experiments for
nickel binding as well as binding capacity
results would be presented at the
conference. In addition, studies to determine
the reversibility on the nickel binding as well
as binding capacities for various Alfalfa
varieties will be discussed.
Keyword(s): bioremediation, alfalfa, Medicago sativa, nickel, metal binding.
Poster presentation.
Inactivated copper-sensible and copper-
tolerant strains of Mucor rouxii cultured in
the presence and also absence of the metal
were tested for their potential to uptake
copper ions from solution. Batch
experiments were performed to determine
the pH profile, time dependency, binding
capacity and reversibility on the binding.
Biomasses studied showed a high affinity
for copper ions at pH 5, and the highest
capacity for Cu(II) uptake was exhibited by a
tolerant strain grown in the presence of
copper. Approximately 100% stripping or
removal of the copper absorbed was
obtained when the metal was extracted by
treatment with 0.1 M HCl.
These preliminary findings suggest that the
presence of copper in the media allows
development of chemical functional groups
(most likely carboxyl groups) on the fungal
cell walls. This phenomenon can have
useful applications for metal removal from
contaminated water.
Keyword(s): Mucor rouxii, copper binding, bioremediation.
Oral presentation in bioremediation session.
Organotin compounds are used as
fungicides and antifouling agents which are
incorporated into paints for use in sea
vessels. These compounds have been
found to be a threat to the environment.
Method development for the determination of
tin by Zeeman GFAAS was studied. Different
matrix modifiers were evaluated including
NH4H2PO4/Mg(NO3)2 which produced the
optimum tin signal. The effect of acids such
as HNO3 and HCl on the tin signal was
investigated. The analytical method
developed in our investigation was used to
determine tin content in marine sediment
from La Paz, Baja California Sur, Mexico.
Keyword(s): tin, method development, marine environment.
Poster presentation.
Growth of a Pseudomonas fluorescens
species has been demonstrated with TNT
as the sole nitrogen source and acetate as
the carbon source. While only 10% of the
transformed TNT was accounted for by
HPLC analysis, growth measurements
indicate that a significant amount of the TNT
nitrogen present was converted to biomass.
2-amino-4,6-dinitrotoluene was identified as
a dead end metabolite. Picric acid and
trinitrobenzene were also identified as
intermediates and may be part of the
nitrogen use pathway. The use of TNT as a
nitrogen source may lead to ring cleavage
and mineralization, since growth has also
been observed with TNT as the sole
nitrogen and carbon source.
Keyword(s): trinitrotoluene, bioremediation.
Oral presentation in bioremediation session.
A model was developed to assist in
determining the fate and transport
anticipated during remediation of
trinitrotoluene (TNT) contaminated soils. The
model is physically based to incorporate
biological, physical, chemical and
environmental factors in predicting the
degradation fate of trinitrotoluene (TNT).
Model applications range from contaminant
sources such as abandoned mines, waste
heap piles, munitions industrial waste water
lagoons, military bombing ranges, and
weapons maintenance and disposal
operations.
Keyword(s): remediation, model, TNT, munitions, wastes.
Movement of chemicals on land surfaces
due to shallow overland flow of infiltration
excess rain water poses a potential
environmental hazard to receiving waters
downstream. Such problems are abundant
in the chat-contaminated soils of southeast
Kansas. Surface water travels two to three
orders of magnitude faster than subsurface
flow and is sometimes responsible for
removing substantial amounts of chemicals
which are initially mixed in shallow soils. A
physically-based mathematical model will be
presented to represent this mode of
contaminant movement, with emphasis on
overland flows in regions neighboring
streams. Some modeling results will be
presented and future applications will be
discussed.
Keyword(s): surface water, contaminant transport.
Poster presentation.
During the summer of 1994, an agricultural
and a pristine site within the Konza prairie
research area were identified to study the
spatial structure of the surface infiltration
properties. About 40 surface locations were
selected for sampling over 10 m by 10 m
areas at each of the two sites. The spatial
locations were designed to obtain a
balanced support for variogram
computations. The Guelph Permeameter
was used for the determination of soil
properties. The infiltration properties
examined were the saturated hydraulic
conductivity, the matrix flux potential,
sorptivity and the alpha parameter. These
properties were analyzed using
geostatistical tools. Even though the
individual plots appeared homogeneous, the
hydraulic properties (specially saturated
hydraulic conductivity) exhibited very wide
variability. Correlation lengths of these
properties were found to be in the order of
meters. The utility of such analysis in our
understanding and modeling of field scale
behavior of subsurface water will be
investigated.
Keyword(s): infiltration, spatial variability, geostatistics.
Poster presentation.
Determining the efficacy of treatment effects
by replicated field trials is truly confounded
by the presence of spatial variability in most
field soils. It is not possible to construct two
field sites which are perfectly alike with
respect to their soil properties and initial
contaminant concentrations. When the
treatments involve vegetative remediation
strategies, this problem is further
aggravated by the additional uncertainty
introduced by factors like root density.
Geostatistics provides us a powerful
mathematical tool for designing, analyzing
and comparing treatment effects. It has
been demonstrated that inclusion of
information on covariance structure of
spatially varying quantities (in this case
contaminant concentrations) increases the
statistical power of hypothesis tests. Some
applications of geostatistics to actual design
and implementation of field sites will be
presented.
Keyword(s): spatial variability, hypothesis testing, geostatistics.
Oral presentation in environmental assessment and
decision making session.
Macropores can be significant paths of flow
in the vadose zone and can transport water
and chemicals at velocities much faster
than predicted with conventional solute
transport models. At the Rocky Flats
Environmental Technology Site in Golden,
Colorado, plutonium-contaminated oil leaked
from deteriorated drums and was
subsequently airlifted by winds and
deposited on soils in a cast and south east-
trending plume. Macropores have been
shown to occur at that site and must be
considered in a model predicting the fate of
Pu-238-239. While macropore models exist,
few studies have calibrated using field data.
This study was conducted to determine the
feasibility of using a 2-D finite element
macropore model at that site to predict the
fate of Pu-238-239.
A well-defined system will be used to
determine the feasibility of modeling
macropores and to calibrate the model.
Presently, a column is being manually
packed with sieved soil into a 80 cm long
and 30 cm diameter column. A macropore
will then be created in the column. The
sample will be tested under a variety of
rainfall rates and boundary conditions.
Field samples will also be used to evaluate
the model. Two undisturbed soil columns
(35 cm by 50 cm) were excavated from a
structured clay soil near Boulder Creek. A
rain simulator, which consisted of
hypodermic needles attached to the bottom
of a short cylinder, applied water at 6 cm/hr.
A 49 cell grid sampling device collected the
outflow. Tensiometers showed that no flow
occurred until the sample was fully
saturated. Most of the flow occurred within
two grid cells, and conservative tracers
exhibited breakthrough at 0.5 pore volumes
which suggest some type of macropore
flow.
Keyword(s): macropore, model calibration, radio active waste, vadose zone modeling.
Oral presentation in fate and transport session.
The Haskell Environmental Research
Studies Center (HERS), located at Haskell
Indian Nations University (HINU) has joined
with the Great Plains-Rocky Mountain
Hazardous Substance Research Center
(GP-RM HSRC) to administer the Native
American and Other Minority Institutions
Program (NAOMI). The NAOMI Program
was funded to involve minority educational
institutions in research, training and
technology transfer. The HERS Center
currently administers several programs.
One primary element of the NAOMI Program
is a Seminar Series which provides public
education on hazardous substances and
related environmental issues. Seminars are
disseminated by the mailing of videotapes or
through satellite downlinks. The NAOMI
Program has been able to provide funding
for several individuals from participating
institutions to attend the Tenth Annual
Conference on Hazardous Waste Research
in Manhattan, Kansas, during May 23-24. In
addition, NAOMI was able to match five
scholars from Native American and other
minority academic institutions with HSRC
researchers through the Summer
Cooperation Program. HERS Staff, in
association with the U.S. Department of
Agriculture, worked to coordinate a program
which was part of the twenty-fifth
anniversary celebration of Earth Day in
Washington, DC. The program brought
together tribal leaders, elders and scientists
in a panel discussion of global change
issues. HERS also received funds from the
Department of Defense to provide certified
training to students from Tribal Community
Colleges. This workshop is part of an on-
going curriculum development project. The
first workshop under this program is
tentatively scheduled for June 18-30, 1995,
at Haskell Indian Nations University. The
HERS Staff is hoping to provide training for
forty participants. HERS has been able to
act as an information clearing house by
sending grant solicitations to participating
institutions where applicable. NAOMI
Seminar videotapes are available for use in
the library of Kansas State University and
can be obtained nationwide through
interlibrary loan.
Keyword(s): Native American, minority, research, technology transfer, hazardous substances.
Poster presentation.
Organic ligands may affect the adsorption of
heavy metals to soil by the formation of
complexes. Batch adsorption experiments
were conducted to determine the effect of
citrate on the adsorption of zinc to soil. At
concentrations ranging from 0 to 1500 mmol
L-1, the adsorption of zinc by a soil under
constant pH was measured in the presence
of citrate of 0 to 10000 mmol L-1. It was found
that the adsorption of citrate by soil was
independent of zinc concentration, but the
adsorption of zinc by soil was dependent on
citrate concentration. Zinc adsorption
increased with increasing citrate
concentration up to 3000 mmol L-1; zinc
adsorption decreased with increasing citrate
concentration beyond 3000 mmol L-1. The
adsorption of the zinc-citrate complex was
ligandlike at this pH, and the increase or
decrease of zinc adsorption was due to the
formation of the zinc-citrate complex.
Keyword(s): adsorption, heavy metal, organic ligand, ligandlike complex.
Oral presentation in heavy metals session.
Bioremediation, the process of
microorganisms controlling and degrading
contaminants, is one of the fastest growing
hazardous waste cleanup alternatives.
Fourier transform infrared (FT-IR)
spectrometry is used to monitor the uptake
and degradation of volatile organic
compounds (VOCs) in contaminated ground
water. Previous studies, using FT-IR
spectrometry to monitor, suggest that
toluene was degraded by adapted alfalfa
plants and/or their associated
microorganisms. A plant chamber was
designed to model contaminated ground
water flow. Alfalfa was planted in a 90 cm x
40 cm x 35 cm chamber. 200 mL/L of
trichloroethylene (TCE) spiked ground water
was continually fed into one half of the
chamber. The other half of the chamber
received 100 mL/L each of 1,1,1-
trichloroethane (TCA) and chloroform
(CHCl3). Present studies include monitoring
1,1,1-trichloroethane, chloroform and
trichloroethylene from a population of
adapted plants. The gas phase above the
plants in the chamber at various growing
stages was monitored for accumulation and
depletion of contaminants. Also headspace
gas samples of the inlet and outlet wells of
the plant chamber were measured. The
transpiration rate of individual plants was
successfully monitored using deuterium as
an internal standard in contaminated ground
water. Studies suggest very little
contaminant was taken up from the flow of
water through individual plants. Also a mass
balance of the alfalfa plants and the plant
chamber is being determined. The
concentrations of the contaminants and their
by-products in the alfalfa plants are being
measured. The FT-IR spectrometer can
quickly and efficiently monitor the effects of
plant bioremediation.
Keyword(s): FT-IR, bioremediation, volatile organic compounds (VOCs).
Oral presentation in phytoremediation session.
The United States Department of Defense
(DoD) has literally thousands of sites that
have been contaminated from past military
activities. The cost of remediating these
sites using existing technologies, such as
activated carbon, will be astronomical.
Advanced oxidation processes (AOPs) have
promise because they effect on-site
destruction of the contaminants. However,
AOPs must be optimized for treatment,
because without increased process
optimization AOPs could result in costs
similar to that of activated carbon. AOPs are
by definition those oxidation processes that
utilize the hydroxyl radical ( OH) as one of
the (or the) primary contaminant oxidation
mechanisms. Since the hydroxyl radical is
an unstable chemical species, AOPs must
be designed to produce the radical on-site
through a variety of photolytic (illuminated)
and/or chemical reactions (dark).
To optimize AOPs and reduce remediation
costs, the mechanistic workings of various
AOPs must be understood. The kinetics of
AOP systems are complex. The rates of
contaminant removal and reaction orders
often change according to the water matrix
and oxidant concentrations. Maximum rates
of treatment have occasionally been
observed for certain oxidant concentrations
and ratios. We have developed a kinetic
model and used the model to derive a rate
expression that describes the OH radical
concentration given a set of operating
conditions. The model explains well some of
the observed complex dependence
behaviors of AOPs, with the following
expression:
This model and derived expression is useful
for process optimization. In its final form,
this paper will present experimental results
of process optimization for hazardous waste
treatment. Kinetic constants of contaminant
degradation will be presented as a function
of test parameters such as pH, O3 and
H2O2 concentrations and ratios,
contaminant concentration, water
characteristics including hardness,
carbonate content, alkalinity, and radical
scavenger concentration. A major emphasis
of this paper will be to test the mechanism
proposed for AOPs. The kinetic results will
be used to validate or modify the proposed
AOP kinetic model. Limitations of the model
will be identified. Optimal operating
conditions and recommendations for
hazardous waste treatment will be made
according to the experimentally validated
kinetic model.
Keyword(s): advanced oxidation processes, contaminants degradation, remediation, optimization.
Oral presentation in chemical destruction session.
Heavy metal contamination of soil is a
common problem encountered at many
hazardous waste sites. Lead, chromium,
cadmium, copper, zinc and mercury are
among the most frequently observed metal
contaminants. They are present at elevated
concentrations at many National Priority List
sites. Heavy metals are toxic to people and
pose a great risk for safe ground water
supply. Once released into the soil matrix,
most heavy metals are strongly retained and
their adverse effects can last for a long time.
Chelating extraction of heavy metals from
contaminated soils has recently been seen
as a treatment method. However, results
from our laboratories show that, in order to
recover the heavy metals and reclaim the
chelating agents, only suitable chelating
agents should be used for this application.
The structure and electronic configuration of
a chelating agent are important to its metal-
complexing ability, speciation, selectivity,
biodegradability, toxicity and transportability.
The molecular connectivity index model
which can encode the structural and
electronic information of a chelate is seen
as a useful tool to predict the said properties
and aid in the selection of useful chelating
agents for extractive removal of heavy
metals from contaminated soils. The
previous findings of various researchers
have provided a simple method of encoding
the essential information concerning a
molecule into terms which can be employed
in a linear equation; the latter is employed to
validate or reject any or all variables. The
approach is based on the assumption that
there is, within the structural formula,
sufficient information such that a useful
index based upon non-empirical counts of
atoms can be calculated. The technique has
been found useful for correlating molecular
structures with properties such as molar
refraction, polarizability, water solubility,
chromatographic retention data, orientation
of ring substitution, phenol toxicity to fathead
minnows, antimicrobial action of phenyl-
propylethers, flavor and taste threshold, and
many others. Relevant properties of the
metals can be included in the LFER
providing a basis for developing a “designer”
chelator. New methods for selection of
variables and regression diagnostics have
been employed.
In its final form, this paper will present the
results of using the molecular connectivity
index model to correlate the metal-
complexing ability of a large number of
chelating agents with their molecular
structure. The developed model will be
useful for predicting metal complexation for
other agents for which the complexing
constants are unavailable. The limitations of
this model will be identified. This paper will
also present the experimental results of
heavy metal extraction from soil using a few
selected chelating agents. The removal of
metals including cadmium, copper, lead and
zinc has been studied under different pH,
soil suspension, total chelator concentration,
total carbonate concentration, and age
conditions and will be presented. In
particular, the selectivity and subsequent
recovery of heavy metals will be
emphasized.
Keyword(s): structure-activity, metal, soil, chelator, contamination, remediation.
Oral presentation in heavy metals session.
The environmental fate and biological effects
of methyl-tertiary-butyl ether (MTBE) is of
concern because, among other factors, it is
highly soluble in water, and potential ground
water contaminations may occur through
accidental exposures and spills. The effect
of MTBE on the hexadecane mineralization
by natural consortia of hydrocarbon
degrading microorganisms was investigated
using radiorespirometric techniques. We
found that MTBE increased oxygen
consumption but that concentrations
approaching 1.8 mg/l inhibited the
hexadecane mineralization potential of
consortia found in a variety of soils by up to
50%. These results indicate that MTBE can
be metabolized in the environment but that
toxicity may adversely affect overall
biodegradation of hydrocarbon constituents
of liquid fuel.
Keyword(s): MTBE, hexadecane, radiorespirometry.
Oral presentation in bioremediation session.
Each year approximately 285 million scrap
tires are added to stockpiles, landfills or
illegal dumps across the United States. The
Environmental Protection Agency (EPA)
estimates that the present size of the scrap
tire problem is 2 to 3 billion tires. The
existing tire piles pose fire and health
hazards. There is a large number of tires
being accumulated in rural areas. For
example, Cloud County, a rural county in
Kansas, has a tire pile consisting of
approximately 573,000 mixed car, truck and
tractor tires. Under current state law in
Kansas, these tires must be shredded
before storing in landfills. Introduction of
scrap tire rubber into roads has the potential
for reducing this waste problem. The
feasibility of using larger rubber chunks from
shredded tires as aggregates in cold-mixes
for road construction was investigated in a
study conducted at Kansas State University
under the sponsorship of Kansas
Department of Transportation (KDOT). The
research was directed toward development
of a chunk rubber asphalt concrete (CRAC)
mix design for low volume road construction
using local aggregate, shredded tire rubber
chunks and cationic emulsion (CMS-1).
Various parameters of cold mix as well as
inclusion of fly ash following KDOT's
practice of using Type C fly ash in cold mix
were studied. Low Marshall stability and high
flow values were obtained for asphalt mixes
with CMS-1 emulsion. A medium-curing
cutback was also experimented in the cold
mix. A set of mixes using different
combinations of chunk rubber content,
emulsion content and fly ash amount were
tested. Based on the Marshall stability
results, some of these mixes appeared to
be suitable as binder courses or stabilized
drainable bases for low volume roads.
Marshall stability results of mixes with 10%
Type C fly ash showed optimum CMS-1
emulsion contents of 6.8, 7.3 and 7.8% for
2, 4 and 6% rubber, respectively. The
Marshall stability values decreased for
increasing rubber contents. The target
Marshall stability value of a suitable cold mix
at 110 F was required to be 500 Ibs. A mix
with 10% Type C fly ash, 2% rubber and 6%
CMS-1 emulsion showed an average
Marshall stability value of 420 Ibs. Higher
stability values are expected if the maximum
aggregate size in the mix is increased. If 20
Ibs of chunk rubber equivalent is produced
per tire, then a one mile long and 24-ft wide
low volume road with a 4-in thick base built
with this mix can incorporate approximately
5,360 tires. This application can minimize
the scrap-tire waste problems of rural
communities.
Keyword(s): chunk rubber, cold-mix, scrap tires, low-volume road, mix design.
Oral presentation in pollution prevention/waste
minimization.
Environmental hazards are posed by the
presence of 2,4,6-trinitrotoluene (TNT) and
its degradates in munitions-contaminated
soils. TNT sorption and bound residue
formation must be characterized accurately
to predict TNT transport and fate in soils.
We found TNT sorption was concentration
dependent and nonlinear for concentrations
between 80 mM and 300 mM L-1. Sorption did
not approach equilibrium even after 168 d.
Consequently, predictions regarding
transport and fate of TNT made on 24 h
equilibration and linear adsorption may not
be accurate. Particularly critical are TNT
interactions with the top several centimeters
of soil, which are highly contaminated at the
sampling site. TNT sorption was determined
in the presence and absence of solid phase
TNT. We observed TNT adsorption
continued to increase until the end of the
experiment (168 d). Adsorption was rapid
and 35 and 38% of the total 14C (added as
14C-TNT) was adsorbed within 0.5 h in both
soils (with and without solid phase TNT).
After 168 d, 79% of 14C was adsorbed by
soils with solid phase TNT versus 93% for
soils without solid phase TNT. The readily
available (CaCl2-extractable) and potentially
available (acetonitrile-extractable) pools of
adsorbed TNT decreased rapidly with time.
The 14C-activity continued to increase in the
organic fractions (fulvic acid and humic
acid) and a higher percentage of 14C was
found in fulvic acid than in the humic acid
fraction. Approximately one-half of the total
14C was irreversibly bound, and only a very
small amount was released when treated
with strong alkali (10% KOH in methanol)
and strong acid (1N HCI in methanol). Our
observations indicate that bound residue
formation constitutes a significant route of
detoxification in soil.
Keyword(s): TNT, bound residue, sorption.
Poster presentation.
Volatile organic chemicals present at
Superfund sites preferentially partition into
the soil gas and may be available for
microbial degradation. A simple mass
transfer model for biodegradation for volatile
substrates is developed for the aerobic
decomposition of aromatic and aliphatic
hydrocarbons. The mass transfer analysis
calculates diffusive fluxes from soil gas
through water and membrane films and into
the cell. The model predicts an extreme
sensitivity of potential biodegradation rates
to the air-water partition coefficients of the
compounds. Aromatic hydrocarbons are
removed rapidly while the aliphatic
hydrocarbons are much slower by orders of
magnitude. Furthermore, oxygen transfer is
likely to limit aromatic hydrocarbon
degradation rates. The model presents
results that cast doubt on the practicality of
using methane or propane for the
cometabolic destruction of trichloroethylene
in a gas phase bioreactor. Toluene as a
primary substrate has better mass transfer
characteristics to achieve more efficient
trichloroethylene degradation. Hence, in
sites where these contaminants coexist,
bioremediation could be improved. The
model is extended further to examine the
influence of water potential on transport and
transformation rates within microbial
biofilms present in unsaturated soils. Water
potential has multiple effects on overall VOC
removal through the thickness of the biofilm,
the molecular diffusivity of substrates
through the biofilm, and microbial
physiology.
Funding for this work was provided by the National Institute
of Environmental Health Sciences Superfund grant 3P42
ES04705-08.
Keyword(s): VOC, biodegradation, unsaturated soil, biofilms.
Poster presentation.
The effect of five different soil gas oxygen
concentrations on the rates of degradation
of pentachlorophenol (PCP) and polycyclic
aromatic hydrocarbons (PAHs) was
investigated by conducting a laboratory
evaluation of field contaminated samples.
The soil used in this evaluation was taken
from the Champion International Superfund
Site in Libby, Montana. Radiolabeled PCP
and pyrene were spiked onto the soil, and
mineralization was measured. In addition,
the fate of the contaminants in soil was
determined by conducting a chemical mass
balance on 14C that included volatilized,
solvent-extractable, and non-solvent
extractable fractions. Results are applicable
to the design and management of prepared-
bed bioreactors treating wood preservative-
contaminated soil.
Keyword(s): bioremediation, prepared-bed bioreactor, oxygen tension, contaminated soil.
Oral presentation in bioremediation session.
The goal of this project is to understand
factors which promote or retard biomass
accumulation in porous media with an intent
to apply such understanding toward
beneficial manipulation of permeability and
mass transport properties. Creation of
subsurface biobarriers by selectively
plugging permeable strata with microbial
biomass is being explored as a means of
reducing migration of ground water
contaminants from hazardous water sites.
Likewise, impermeable biobarriers may
serve as a means of prohibiting subsurface
dissolved oxygen transport to sites
producing acid mine drainage. However
fundamental questions must be answered in
order to properly establish both the technical
feasibility and methodology for applying
biobarrier technology. Such questions
include: 1) are biobarriers an effective
means of plugging high permeability zones?,
if so, 2) what length of formation flow path
can be plugged?, 3) how long will they
persist?, 4) can aerobic conditions be
created and sustained, and 5) once
developed, what are the residual
permeability and mass transport capacity?
Research results which address these
questions will be reported in this paper.
Cylindrical columns (6” diameter x 36”
length), constructed by MSE Inc. were
treated with epoxy polymers to prevent
water channeling along the walls and filled
with sand. Initial permeability of these
columns was in the range of 10-14 darcy.
Two pore volumes of Ultramicrobacteria
(UMB), derived from an environmental strain
of Klebsiella spp., were introduced into the
columns at a concentration of 1.0 x 106
cells/ml, followed immediately by two pore
volumes of citrate nutrient. Permeabilities at
all levels sharply declined after two days and
continued until column permeability was 5%
of its original value.
Keyword(s): ground water quality, permeability reduction, bioremediation, selective plugging.
Oral presentation in fate and transport session.
The water quantity and quality of two
adjacent agricultural watersheds were
compared. The stream draining one
watershed was farmed to the edge of the
stream (unbuffered) and the stream draining
the other watershed was “buffered” with 9 m
(4 rows) of poplar trees on each side. The
buffer was designed as a living filter to
reduce agricultural non-point source
pollution.
The pattern of nitrate concentration in the
outflow of the watersheds in 1994 was
similar to 1993; the buffered watershed
consistently had lower nitrate levels. The
nitrate concentration in the tile lines feeding
each stream closely paralleled watershed
outlet concentrations, showing that the tile
line flow must be intercepted to fully control
water quality at this site. Ground water
nitrate levels in piezometer transects
through the buffer showed generally low
levels of nitrate, with a trend of decreasing
nitrate concentration across the buffer from
the field to the stream.
A section of the buffer which has been in
place for 7 years was excavated to
determine the distribution of macronutrients,
rnicronutrients and carbon in the trees
(leaves, stem, roots) and in the soil to a
depth of 1.8 m. In addition, preliminary data
was collected to determine the impact of the
poplar buffer on rhizosphere microbial
populations potentially important to
bioremediation. Increased populations of
heterotrophic and denitrifying organisms
relative to the surrounding soil were
observed in the rhizosphere of poplar.
Keyword(s): nitrate, non-point source, phytoremediation.
Poster presentation.
Losses of fuel hydrocarbon contaminants
and geochemical evidence were obtained in
a shallow sandy aquifer downgradient from
a gasoline station operation at Patrick Air
Force Base in Florida. Aerobic respiration,
denitrification, ferric iron reduction, sulfate
reduction and methanogenesis patterns
were measured in relationship to the
dissolved fuel constituents benzene,
toluene, ethylbenzene and xylene (BTEX).
Aerobic respiration and methanogenesis
accounted for the greatest mass of BTEX
mineralization. Calculated first order
biodegradation rate constant was 0.014
week-1 for the dissolved BTEX. Based on
stoichiometry of benzene oxidation
reactions, the ground water at the site had
an assimilative capacity to degrade the
highest detected dissolved BTEX level of 7.3
mg/liter before the plume would migrate 370
meters from the source area.
Keyword(s): intrinsic bioremediation, BTEX, rate constant, stoichiometry
Oral presentation in bioremediation session.
Significant amounts of freons, predominantly
CFC-11 (trichlorofluoromethane), are
trapped over long periods in polyurethane
foams. These foams are one of the most
widely used forms of plastic with varied
applications. Polyurethane and polystyrene
form the bulk of polymeric foams for which
freons have been used as the foaming
agents. Initial concentrations of freons in
such foams are in the 20-30% range.
Results of a survey of freon residues in
polyurethane foam revealed that, in the
absence of free exchange with air, these
foams effectively retain freon for long
periods of time. Polyurethane foam samples
from 15 year old refrigerators were found to
contain freon at concentrations ranging from
15-20% w/w. These concentrations clearly
indicate that polyurethane represents a
large, long-term source of freon in the
environment.
To estimate the long-term release of freon,
an experimental release model has been
developed. The model takes into account
such parameters as polymer film thickness,
temperature and photoinduced degradation
of polyurethane foam. The model has been
validated with experimental results. The
results show that the release of freon from a
polymeric foam is dependent on
permeability across the polymer film. The
permeability is dependent on environmental
parameters to which the foams are
exposed. The most pertinent of these are
temperature and exposure to sunlight. To
monitor the effects of these parameters, a
series of weathering experiments were
undertaken. A QUV accelerated weathering
tester was used for simulation of the
damage to the polymer structure from
exposure to the elements. Some of the foam
samples were also aged under natural sun
light. Freon content of foam was determined
periodically. The determinations were
carried out by extracting freon with methanol
and injecting methanol solution into a
calibrated gas chromatograph-mass
spectrometer (GC-MS). Studies showed
that freon release from foams is accelerated
by exposure to near UV region of the solar
radiation and an increase in temperature.
The rate of release of freon from foam was
found to be significantly higher at
temperatures greater than 70 C. The
release was found to follow first order
kinetics with respect to time and
temperature.
Keyword(s): freon, polyurethane foam, experimental model.
Oral presentation in environmental assessment and
decision making session.
The term “Community Involvement” is the
environmental catch phrase of the 90's. The
commitment to keeping communities
involved in the process of cleaning up
hazardous waste sites has been important
since the early 80's with the “lessons
learned” at Love Canal, the canal that
seeped huge quantities of poisonous
chemicals onto a community in the City of
Niagara Falls, New York.
The Superfund Program, under the
jurisdiction of the Environmental Protection
Agency (EPA), is committed to the timely
and efficient identification and cleanup of
hazardous materials spills and
contaminated sites, with the ultimate goal of
protecting human health.
For years, communities with culturally
diverse populations have felt the lack of
involvement and active participation in the
decision making process for cleanup
alternatives at hazardous waste sites.
This presentation will look at various
communication tools and will highlight
research on three Superfund sites with
culturally diverse populations where the
community involvement process really
worked.
Implementation of the community
involvement process consists of developing
innovative approaches with the affected
communities to ensure that the
communities regard specific approaches as
“meaningful participation.”
Keyword(s): community involvement, culturally diverse, Superfund.
Oral presentation in community involvement session.
As the Great Plains-Rocky Mountain
Hazardous Substance Research Center
celebrates its 10th anniversary of its annual
conferences with the theme, “10 Years of
Progress: Solving Old Problems and
Preventing New Ones,” this paper presents
industry perspective on environmental
management history and shows how
Corporate America is responding to
regulatory challenges and public pressure.
This paper consists of three parts. The first
part deals with a brief regulatory history
particularly relative to U.S. Environmental
Protection Agency's approach on end-of-
pipe controls vs. pollution prevention. The
role of Emergency Planning and
Community-Right-to-Know Act and Toxics
Release Inventories in moving the
environmental management direction
towards pollution prevention is highlighted.
The second part of this paper presents
“Environmental Management Continuum”
(Continuum) describing how the regulated
industry has responded to the evolving
regulations. Different phases of the
Continuum including denial, avoidance,
compliance and pro-action are illustrated. A
discussion on how the environment has
become a strategic issue (rather than just a
compliance problem) for Corporate America
is presented.
Finally, this paper presents a 10-step
approach to achieving environmental
excellence, the final stage in the Continuum.
Examples of industry leaders that are
successfully applying elements of this
approach are provided.
Keyword(s): regulations, pollution prevention, environmental management, environmental excellence.
Oral presentation in technology transfer session.
The objective of this research is to
investigate the impact of vegetation—fescue
(Festuca arundinacea)—on the fate of
carcinogenic and recalcitrant
benzo(a)pyrene in soil. The effect of
vegetation will be evaluated by determining
the distribution of 14C among soil, plant
tissue, leachate and CO2 evolved in planted
and unplanted soils using plant growth
chambers during a 6-month experiment.
These data will be analyzed to ascertain if
there are differences between vegetated and
non-vegetated soils with regard to leaching,
degradation, plant uptake and mineralization
of the 14C-benzo(a)pyrene. The beneficial
effects of vegetation planted in soil
contaminated by benzo(a)pyrene is
anticipated.
Keyword(s): vegetation, benzo(a)pyrene, soil, plant, rhizosphere.
Oral presentation in phytoremediation session.
Past disposal practices at munitions
production facilities have resulted in
numerous acres of soil contaminated with
nitroaromatics, particularly 2,4,6-
trinitrotoluene (TNT). TNT and its
degradates are toxic to biota, and
contaminated soils need to be remediated to
ensure environmental quality and safety. We
previously demonstrated that Fenton
oxidation effectively destroyed and
mineralized TNT in both pure solution and
aqueous extracts of TNT-contaminated soil.
Our objectives were to develop practical
approaches for remediating TNT-
contaminated soils by Fenton oxidation. This
was accomplished by proposing three
possible remediation schemes. The first
considered combining soil washing of TNT-
contaminated soils with Fenton oxidation of
wash waters. Using this approach, we
determined the effects of temperature and
humic and fulvic acids on efficiency of TNT
removal and destruction. Secondly, we
proposed combining soil washing with
phytoremediation and determined the
phytoxicity of the washed soil to tall fescue
(Festuca arundinacea) germination and
early development. The third approach
considered direct Fenton oxidation of
contaminated soil-slurries. Results indicated
that aqueous soil washing can effectively
reduce CH3CN-extractable TNT
concentrations but large H20 volumes are
required to meet EPA's remediation goal
(17.2 mg TNT kg-1). The volume of H20
required can be reduced if wash water
temperature is increased. Fenton oxidation
of TNT in contaminated wash water was
also demonstrated with greater than 90%
mineralization achieved. Addition of humic
and fulvic acids to aqueous TNT did not
greatly alter the efficiency of destruction and
indicates that Fenton oxidation could be
effective on a variety of aqueous soil
extracts. We also demonstrated that direct
Fenton oxidation of soil slurries removed
TNT from solution and produced extractable
soil concentrations below remediation goals.
These results indicate that when Fenton
oxidation is combined with soil washing,
phytoremediation, or used directly on soil-
slurries, it is an effective abiotic remediation
treatment for TNT-contaminated soils.
Keyword(s): munitions, TNT, Fenton oxidation, remediation.
Poster presentation.
Due to the chemical spills, leaking
underground storage tanks, landfills and
other pollution sources, soil and ground
water are commonly polluted by hazardous
organic chemicals. The interface between a
clay subsoil and overlying sandy soil is a
zone of high concentration of contaminants,
water, organic carbon, soil nutrients and
microorganisms. A study to investigate
optimal bioremediation methods for clean-up
of contaminated textural interfaces is being
conducted. In the first step of the study,
multi-layer soil columns will be constructed
and contaminated with PAHs. Relationships
between bioremediation and microbial
nutrients, water table levels, fluctuation of
water level, and type of the soil will be
investigated in the columns. For assessing
the relationship, physical, chemical, and
microbial properties of soil and column
effluent, flow of nutrients and PAHs, the
degradation rate will be measured. In the
second step of the study, a pilot scale
microcosm will be constructed. It will include
experiments to survey the multi-dimensional
nature of the fate and transport of organic
contaminants at the interface, and
biodegradation variables will be optimized.
To make use of the interfacial biokinetics
observed in the column experiments and
predict the effectiveness of bioremediation
under similar in situ conditions, a
mathematical model will be developed,
which will focus on evaluating fate and
transport of organic contaminants as a
result of bioremediation at textural interfaces
between coarse and fine soils. The model
formulation accounts for the fate and
transport of discontinuous immiscible phase
in terms of biodegradation variables.
Keyword(s): bioremediation, microorganisms, polyaromatic hydrocarbons, NAPLs, ground water.
Poster presentation.
Destructive adsorption of chlorocarbons on
nanoscale calcium oxide particles has been
successful in laboratory scale experiments.
For effective implementation of
nanotechnology, studies are being carried
out at the bench scale level for these
reactions. For experimental convenience,
the reaction between CCl4 and CaO is
considered as a representative reaction.
The first phase of the work involved the
determination of optimum parameters that
affect the surface area of the activated
particles. The particles were heated under a
constant supply of nitrogen. Rate of heating,
duration of heating, temperature, flow rate of
nitrogen, and particle size were found to be
the important factors.
The second phase of the work involves
design and fabrication of the reactor
assembly system and study of the
adsorption reaction. A batch of 50 gms of
the activated CaO particles can be treated in
the fixed-bed reactor. Nitrogen is employed
as a carrier gas for the CCl4 vapors.
Temperature of reaction, duration of
reaction, pressure inside the reactor,
surface area of CaO, particle size, and the
flow rate of the gas mixture are important
parameters that govern the extent of
conversion of CaO particles.
Keyword(s): destructive adsorption, nanotechnology, chlorocarbons.
Oral presentation in chemical destruction session.
Many numerical models developed to
describe the two phase flow of hazardous
organic liquids in the subsurface requires
the capillary pressure saturation relationship
as an input parameter. Due to the lack of
data, a variety of techniques are used in
multiflow flow models for estimation of
capillary pressure saturation relationship for
the liquids and conditions prevailing at
hazardous waste sites. Furthermore these
estimations are limited mostly to drainage
curves neglecting the hysteresis effect. This
paper present a new and rapid method to
obtain the capillary pressure saturation
relationship using a flexible wall
permiameter and a continuous flow pump.
The advantages of this method include
eliminating artificially large pores between
the sample container and porous medium,
achieving complete initial saturation as the
sample can be tested at elevated pressures,
and obtaining complete drainage and
imbibition curves in 4 to 5 days.
The porous medium used was a crushed
and sieved industrial silica sand with a mean
grain size of 0.41 cm. The drainage and
imbibition capillary pressure saturation
relationships were first obtained for a
water/air system. Water was withdrawn at a
rate of 1 cc/h using a continuous flow pump
from the initially saturated sample through
the bottom porous plate. At the same time
the non-wetting fluid (air) was allowed to
enter from the top of the sample. The
differential pressure between the non-
wetting phase at the top and the wetting
phase at the bottom was recorded at 100
second intervals using a pressure
transducer and a data acquisition system. At
residual saturation the direction of the pump
was reversed to obtain the imbibition curve.
The porosity of the sample and the pump
rate was used to calculate the saturation
corresponding to pressure measurements.
The same sample was then tested for a
water/p-xylene system. P-xylene was
allowed to enter from the top of sample as
the non-wetting fluid, instead of air, while
water was withdrawn from the bottom of the
sample. The drainage and imbibition
capillary pressure relationships for the
water/air and water/p-xylene systems will be
presented.
Keyword(s): capillary pressure saturation relationship, porous medium, two phase systems.
Oral presentation in non-aqueous phase liquids session.
Soils at the former Nebraska Ordnance
Plant (NOP) are grossly contaminated with
TNT (2,4,6-trinitrotoluene). We found that
this TNT-contaminated soil contains a
variety of Pseudomonads. Our objective
was to determine the potential of a single
microbial species (Pseudomonas
savastanoi) to degrade and mineralize TNT.
All experiments were performed in
Pseudomonas minimal medium (PMM)
containing TNT (60 to 65 mg L-1) as the sole
C source. Cells were prepared as inocula by
growing to approximately mid-log phase in
PMM (with glucose) for 9.5 h. Cells were
then washed twice with saline and
suspended in PMM (TNT sole C source).
The inoculum was added to a concurrent
set of experimental units containing PMM
with either labeled (14C-TNT) or unlabeled
TNT. Unlabeled medium was used for
chemical (TNT, aminodinitrotoluenes, NO2
and NO3) and viable cell count
determinations; samples were taken every 5
to 10 d for 72 d. Daily emissions of 14CO2
and 14C-volatiles were determined from
labeled medium. Results indicate that 14CO2
emissions mimic viable cell populations with
highest emissions within 24 h after
inoculation. When we reinoculated the
medium with a second and third inoculum
(day 36 and 55), 14CO2 production was
similar to the first inoculum. Inoculating the
medium with killed cells did not produce
14CO2. Although 14CO2 production was
related to cell density, overall mineralization
was limited and less than 1% of total 14C
applied. Chemical analysis revealed TNT
concentrations declined to approximately 5
mg TNT L-1 within 72 d; the largest decrease
in TNT concentration occurred within 24 h
after inoculation. The production of
aminodinitrotoluene was minimal and can
not solely account for the loss of TNT. We
also observed a steadily increasing NO2
concentration with time. These results
indicate that Pseudomonas savastanoi can
readily degrade but may have a limited
potential to mineralize TNT.
Keyword(s): TNT, degradation, mineralization.
Poster presentation.
Many projects underway in Kansas involve
application of geophysical and geological
methods to a variety of environmental
questions and problems associated with salt
dissolution. The Permian salts are present
in the shallow subsurface of the central and
southern parts of Kansas. Environmental
problems differ in scale from large-scale salt
water contamination of entire aquifers, to
localized dissolution collapse features.
Causation is a combination of natural
processes and anthropogenic activities
(e.g., irrigation and oil field activities).
An underutilized application of the
workstation is color image transformation
and treatment of the transformed wireline
log data as “seismic” traces for the
purposes of processing, interpretation and
display. Such a transform can combine data
from porosity, gamma and density tools
generating a color coded “crossplot log” for
each well. A well-designed color
transformation of wireline log data from
multiple wells maximizes both spatial and
compositional information content and
provides a readily interpretable image of the
subsurface geology. The transformed
image, in either 2-D or 3-D, can be treated
on the workstation as “seismic” data, easing
the data handling burdens through use of
computerized techniques designed for
interpretation of seismic data.
Various geophysical methods are also used
to image the geology of the shallow
subsurface (0-100 m). These methods
include high-resolution seismic reflection (2-
D and 3-D) vertical seismic profiling, and
ground penetrating radar, and are used in
conjunction with a computerized
interpretation system. The system allows
efficient, detailed and integrated study to be
performed at these sites. Examples from
throughout Kansas are used to illustrate the
utility of using the computer workstation to
perform integrated studies of environmental
problems.
Keyword(s): computer workstations, environmental geology, Permian salts, seismic data.
Poster presentation.
The significance of risk assessment is the
fact that the financial resources allocated for
remediation and environmental services
depend on the magnitude—real or
perceived—of the environmental risk. This
attitude is very important in the middle
European countries where a privatization
process of former state companies has
been underway for about five years. Before
privatization can occur it is necessary to
remediate any damages caused during the
former so called “state care” period.
Damages have occurred, for example, due
to improper storage and handling of fuels,
improper storage of industrial chemicals,
and improper waste disposal practices. In
this situation, a knowledge of risk
assessment procedures has become an
integral part of hydrogeological consulting
practice. However, there are many cases
where the damage assessments appear to
be in error due to problems associated with
the choice of the risk assessment criteria,
both environmental and economic. The
different risk assessment procedures,
criteria and outcomes are demonstrated
using several case histories. In concluding,
the necessity to introduce additional criteria
in the risk assessment procedures is
stressed.
Keyword(s): risk assessment, economics, criteria, soil pollution, ground water pollution.
Oral presentation in environmental assessment and
decision making session.
The mobilization of discrete ganglia, formed
by the residual entrapment of NAPL (non-
aqueous phase liquids) in the soil, is of
utmost importance in subsurface
remediation. This paper utilizes a network
modeling approach to address the stability
of ganglia of various dimensions and to
come up with probabilities of mobilization,
stagnation and break-up of individual
ganglia. A random allocation of pore-sizes
and connecting pore-throats is carried out,
and the stability of a given ganglion is
studied by using a mobilization criteria at
each of the nodes it occupies. The approach
takes into account spatial and temporal
changes in capillary number during pumping
due to changes in pumping velocities and
accelerations. It also takes into account the
changes in capillary number due to possible
changes in pore structure. The model is
used to study the effect of a number of
random pore-size and pore-throat
allocations of a given pore-size distribution,
on a single ganglion. Using these results,
the mobilization and stagnation probabilities
are determined. Results from column and
micromodel experiments are used to
assess the usefulness of network modeling
in evaluating the fate and transport of NAPL
ganglia.
Keyword(s): NAPL, network modeling, mobilization, stagnation probabilities.
Oral presentation in non-aqueous phase liquids
session.
Contamination of ground water and soil is
most often a mixture of pollutants, yet most
quantitative studies of biodegradation either
focus on one compound or describe the
mixture as a single concentration (e.g.,
TOC). Information can be obtained from
these approaches but they do not allow
prediction of the fate of a single pollutant in
the mixture or extrapolation of results to
different mixtures.
As an initial step in the study of the
biodegradation of organic pollutant mixtures,
the biodegradation of benzene, toluene and
phenol by Pseudomonas putida F1 has
been measured and modeled. Each of these
compounds can serve as the sole source of
carbon and energy for this microorganism,
and the initial step in the metabolism of each
is catalyzed by toluene dioxygenase. Batch
cultivation experiments were performed and
the measurements of cell and pollutant
concentration used to test different models
of mixed pollutant biodegradation. In
addition, toxicity tests have been conducted
to verify the effectiveness of biodegradation.
Experiments are currently underway to
measure levels of toluene dioxygenase
activity during biodegradation of different
mixtures with the goal of relating these
levels to the pollutant removal rates.
Keyword(s): biodegradation, mixtures, kinetics, toluene dioxygenase.
Poster presentation.
Di- and Trinitrotoluenes (DNT and TNT) are
contaminants in waste streams from the
manufacture of high explosives;
dinitrotoluene is also a high-volume
intermediate in the production of
polyurethane plastics. These sources have
resulted in soil contamination at weapons
manufacturing sites and chemical plants as
well as bombing ranges and blast sites.
DNT is a potent carcinogen for which the
EPA has established stringent ambient
water quality standards. Because of their
high toxicity to microorganisms, the
nitrotoluene wastes are considered hard to
treat; ppm-level residues in the intake water
can upset the operation of biological
treatment systems. Early studies with
Jimson weed (Datura innoxia) in suspension
culture at LANL indicated that the plant cells
can remove TNT from solution. Our
subsequent research at NMSU has shown
that the removal mechanism is not just
adsorption to the cell surface, but that the
plant cells actively internalize the TNT and
break it down rapidly into a variety of
biotransformation products. Investigation of
the metabolic fate of TNT in Datura species
and in Lycopersicon peruvianum, a wild
tomato species, has shown that reduction of
nitro groups produces aminodinitro- and
diaminonitrotoluenes; oxidation of the methyl
group and denitration or deamination result
in aminobenzyl alcohols,
aminobenzaldehydes and aminobenzoic
acids. The plant cell cultures can tolerate
TNT concentrations up to 200 ppm and
reduce the TNT to low ppm levels within 24
hours. Studies with whole plants of Datura
innoxia, Datura quercifolia, and
Lycopersicon peruvianum in soils
contaminated with 14C-labeled TNT at levels
up to 1000 ppm have shown that the plants
take TNT up from the soil and accumulate
14C-labeled material to concentrations
exceeding the soil levels of TNT up to ten-
fold. Analysis of plant extracts shows that
most of the stored radioactivity is in the form
of the TNT metabolites identified in the cell
culture work. These results show that
uptake, biotransformation and accumulation
by growing plants can be used as an
approach to bioremediate soils
contaminated with nitrated toluenes. Plant
cells in batch culture or whole plants in
hydroponic culture or as components of
constructed wetlands could be used to
bioremediate nitrotoluene-containing waste
water.
Keyword(s): DNT, TNT, bioremediation, plants.
Oral presentation in phytoremediation session.
Alfalfa plants were grown in sandy silt soil
(silt<10%) in a laboratory chamber with two
channels, each with dimensions 35 cm in
depth, 1.8 m in axial length, and 10 cm in
width. The daily water feeding operation to
the growing plants was accomplished by
introducing either pure distilled water or
water contaminated with organics of
interest. Experiments were conducted to
investigate the influence of these alfalfa
plants in bioremediating soil and ground
water contaminated with 1,1,1-
trichloroethane (TCA) and trichloroethylene
(TCE). From July '93 to October '93, TCA
and TCE were fed at 50 and 200 mL/L,
respectively. The contaminants were
introduced into the channel that had been
previously fed with phenol at 500 mg/L. The
fate of these volatile chlorinated compounds
in the saturated zone was monitored using
the gas chromatographic headspace
analysis technique. Methane at a
concentration of about 14 mg/L was
observed in the saturated zone of the
channel. Measurements of the gas phase
samples in the enclosed chamber using FT-
IR indicated the presence of TCA and small
quantities of TCE. No intermediates of
biodegradation were observed during the
gas phase measurements. After
subsequently washing out the contaminants
for 2 months, TCA and TCE were
reintroduced into the plant growth chamber.
One channel was fed with TCA and
chloroform in the entering ground water at a
concentration of 100 mL/L of water; the other
channel was fed with TCE at a
concentration of 200 mL/L of water. Daily
phenol additions in the second case were
accomplished through recharging wells. The
results obtained from this study were
compared to earlier experiments with TCA
and TCE as contaminants where phenol
had been previously fed into the channel as
the inflow contaminated ground water.
Recent studies indicate the presence of
some biodegradation intermediates and the
absence of methane in the ground water
samples; however, using FT-IR, no
intermediates were detected in the gas
phase. The fate of these chlorinated
compounds was also monitored for nearly
two months in the absence of alfalfa plants.
Keyword(s): vegetation, volatile chlorinated compounds, headspace analysis, ground water.
Oral presentation in phytoremediation session.
The energetic utilization of untreated
biomass results in solid waste streams in
the form of wood ash. Despite the fact that
biomass utilization is environmentally
advantageous, because of a steep decrease
in the contribution to the greenhouse effect,
the wood ash produced from biomass
heating systems may well pose an
environmental hazard. This is due to the fact
that biomass concentrates some heavy
metals like cadmium and lead, which result
mostly from the utilization of fossil energy
sources.
The content of heavy metals decides to a
large extent the fate of the resulting waste
streams. If the contamination reaches high
levels, a recycling of the wood ash into
agriculture is made impossible. This is
disadvantageous for two reasons: first, the
disposal of wood ash becomes cost
intensive and further diminishes the
chances of biomass utilization in economic
terms; second, nutrient substances like
calcium, potassium and phosphor, which
are also contained in wood and which make
this kind of material potentially valuable for
fertilizing purposes, are lost and have to be
replaced by virgin raw materials.
Substantial investigations in Austria have
revealed that a large amount of the wood
ash generated by energetic utilization can be
recycled to agricultural use. The base of
these investigations was a rigorous balance
of the process of heat generation by
biomass. This resulted in a clear picture of
the ways heavy metals, especially
cadmium, take through biomass heating
systems. On the base of these findings,
new technological solutions are envisaged
that reduce the waste flow, increase the
amount of wood ash utilized in agriculture,
and decrease the overall hazard which
biomass heating systems pose to the
environment. A detailed review of these
results will be given in the presentation.
Keyword(s): wood ash, cadmium, lead, energetic biomass utilization.
Oral presentation in pollution prevention/waste minimization.
In recent years, researchers have focused
on modeling of multicomponent reactive
transport and developed models to study the
mobility of potentially toxic heavy metals in
the subsurface. However, the research so
far has been concentrated on ground water
regime of the soil. In our study, a
mathematical model for understanding the
fate of a typical heavy metal (zinc) in
unsaturated soil will be developed. The
entire modeling activity will comprise of
three phases. During the first phase, a
geochemical model to describe the soil
heavy metal interactions will be developed.
In the second phase, a solute transport
model will be developed and linked with the
unsaturated flow model which includes plant
uptake. The final phase involves the
sequential solution of the transport and
geochemical models. Local equilibrium
assumption (LEA) will be adopted, so that
the transport and geochemical models can
be decoupled while solving for heavy metal
transport. The model will be used to
simulate heavy metal movement through
unsaturated soil at the laboratory column
scale. The study will provide insight on
movement of heavy metals in chat-
contaminated fields of Southeast Kansas.
Keyword(s): heavy metal, geochemistry, solute transport, mathematical model, unsaturated flow, remediation.
Oral presentation in heavy metals session.
Some of the most common releases of
organic chemicals in the environment, i.e.
gasoline and jet fuel, do not consist of a
single component, but are NAPLs
composed of many water-immiscible and
partially miscible organic fluids. In a non-
homogeneous subsurface environment,
physical heterogeneities may immobilize
NAPLs, creating regions of macro-scale
entrapment. Dissolution of soluble
components from these immobile NAPL
source zones creates long term water
quality concerns.
Two-dimensional dissolution experiments
were conducted in both a 10 meter long
vertical flume and a smaller horizontal
dissolution cell. The experiments simulated
the simplified physical environment of a
coarse gravel heterogeneity in a finer sand
matrix. A synthetic gasoline mixture
consisting of 90% cyclohexane and 10%
benzene was entrapped in the gravel
heterogeneity. The down gradient aqueous
benzene concentrations were measured
along a line of samplers perpendicular to the
direction of water flow. The aqueous
concentrations decreased as the lateral
distance from the NAPL source increased
and as the experiment progressed.
The experiments were modeled using
MODFLOW and a modified version of
MT3D. The aqueous flow field was modeled
using MODFLOW, accounting for the
entrapped NAPL using aqueous relative
permeability correction. The dissolution of
the benzene and the transport of the
aqueous phase benzene solute was
modeled using MT3D incorporating a rate-
limited dissolution term.
Keyword(s): ground water modeling, NAPLs, mass transfer, solute transport.
Oral presentation in non-aqueous phase liquids session.
During start-up, an interconnected process
network, e.g., a network of chemical
reactors, often generates an exceedingly
large amount of the product or products that
do not meet the specifications and thus
should be regarded as waste to be treated
or reprocessed. Moreover, if a hazardous or
toxic component is contained in the product,
its accumulation during start-up may be
such that it potentially poses a high risk.
Naturally, it is desirable that the
accumulation be minimized. Devising the
optimal start-up strategies for an
interconnected process network
necessitates the understanding of the
process transient characteristics for the
different modes of start-up.
For illustration, the present study simulates
the start-up of a system comprising of three
CSTR's connected in series according to
the various modes of operation under either
isothermal or non-isothermal conditions.
Several simultaneous and/or sequential
chemical reactions of different orders are
considered.
Keyword(s): start-up, reactor network, hazardous waste.
Poster presentation.
Incineration has been widely used to
remediate munitions-contaminated soil;
however, rising costs and public concern
mandate less expensive, more
environmentally acceptable alternatives
such as phytoremediation. Grasses can be
effective remediators because of their high
water use, adventitious root systems and
rapid establishment. We determined the
effects of TNT (2,4,6-trinitrotoluene) and its
reduction product, 4-amino-2,6-
dinitrotoluene (4ADNT), on germination and
early seedling development of tall fescue
(Festuca arundinacea Schreb, cv. Rebel
Jr.). Tall fescue seeds were germinated in
nutrient-free agar containing 0, 1.9, 3.75,
7.5, 15, 30, 45 and 60 mg TNT L-1 or 0, 1.9,
3.75, 7.5 and 15 mg 4ADNT L-1. Radicle
emergence was observed within 4 d.
Number germinated, radicle length,
secondary root length, shoot length,
seedling dry weight and respiration were
measured for a 14-day period. Germination,
radicle emergence and seedling
development were not significantly different
from the controls at 1.9 and 3.75 mg TNT
L-1. At low TNT concentrations, respiration
rates tended to be greater than those of the
controls. With increasing TNT
concentration, germination decreased,
seedling development was delayed,
meristematic regions of the radicle were
more disorganized, and secondary root and
shoot development was reduced.
Respiration rate decreased exponentially at
7.5 mg TNT L-1 and greater. Germination
decreased to 53 and 38% at 45 and 60 mg
TNT L-1, respectively. At these high TNT
concentrations radicles emerged without
root hairs. Cell proliferation occurred in the
meristematic region; cells were circular and
disorganized. No secondary root
development was observed and shoot
growth was reduced. Tall fescue
germination was not greatly affected by
4ADNT. Radicle emergence, root and shoot
development were similar to the controls at
1.9 to 7.5 mg 4ADNT L-1. However, root and
shoot development was reduced, and
respiration was depressed at 15 mg 4ADNT
L-1. Our observations indicate a potential
use of tall fescue in remediation of soil
marginally contaminated with munitions
residues.
Keyword(s): TNT, 4ADNT, phytoremediation, tall fescue, Festuca arundinacea.
Poster presentation.
The occurrence of migration of colloidal
particles through subsurface environments
is extensively studied and well
acknowledged. Several field studies have
indicated the transport of microorganisms
and colloidal matter through the subsurface.
Therefore, a proper understanding of
mechanisms and quantification of particle
transport is essential to predict the
contaminant migration in ground water. In
this work a mathematical model to predict
particle transport through porous media is
presented. The important feature of this
model is the representation of soil matrix as
a cluster of pore tubes of different
diameters. The effects of various
parameters responsible for the particle
transport and deposition such as pH, ionic
strength, fluid properties, particle density
and concentration are accounted for in the
model. The effects of these factors are
incorporated through the utilization of a
single combined parameter.
The effects due to the variation of geometry
of the medium and changes in pore size
distribution are also taken into account in the
model formulation. A numerical solution was
obtained by using finite difference scheme to
estimate the rate of change of particle
concentration and net deposition of
particles. The sensitivity analysis of model
parameters was also conducted. The main
advantages of this model are (1) it
incorporates a unique and efficient scheme
to account for particle deposition at various
spatial and temporal levels; (2) it can be
easily modified to estimate facilitated
transport of contaminants; and (3) the
numerical scheme is simple, and an
efficient solution can be achieved without
loss of generality.
Keyword(s): colloids, concentration, density, porous media.
Oral presentation in fate and transport session.
Validation of a 3-D, finite clement, multi-
phase code, FEHMN (Finite Element Heat
and Mass Nuclear) developed at Los
Alamos National Laboratory was performed.
Results from an isothermal 2-D tank
experiment involving the injection of a dense
NAPL into an initially water-saturated, 3-
layered heterogeneous porous medium
were used for validation of the code.
Quantitative data obtained during the
experiment include saturation distributions
within the 2-D tank at various times using a
dual gamma system, injected mass of
NAPL over time, and visual propagation of
the NAPL front dyed red. Based on the
results of the numerical simulations,
additional, more focused 2-D tank
experiments were proposed for further
model validation. This validated model will
be used in our future research efforts on up-
scaling of multi-phase flow parameters to
field problems.
Keyword(s): multi-phase flow, NAPLs, numerical modeling.
Oral presentation in non-aqueous phase liquids session.
Use of thermal processes, such as hot
water flooding and steam injection for the
enhanced recovery of entrapped
hydrocarbons from petroleum reservoirs
have been practiced in the oil industry. The
potential exists for the use of similar
techniques for the mobilization and recovery
of non-aqueous phase (NAPL) waste
products from soils in contaminated
aquifers. However, the direct application of
these techniques for aquifer remediation is
precluded due to some basic differences
associated with the problem of scale, types
of chemicals, expected cleanup levels and
heterogeneities in aquifers. In our ongoing
research, we are investigating the use of hot
water for the mobilization of entrapped
NAPLs under micro and macroscale
entrapment saturations. The objectives of
this research are to understand and model
the mobilization process at various scales of
interest, from the laboratory to the field
scale.
This paper presents preliminary results from
mobilization experiments that were
conducted in soil columns. Sand is packed
homogeneously in a vertical column that
was placed in a temperature controlled
insulated chamber. The bottom of the
column is fitted with a base to which a high-
suction (bubbling pressure) porous plate
can be attached. After saturating the dry soil
with the test NAPL, the column was drained
at the bottom. Suction was then applied at
the bottom to create residual saturation.
After removing the porous plate, hot water at
a known constant temperature was pumped
from the bottom of the column. The effluent
was sampled continuously to determine the
volume of mobilized NAPL. The NAPL
saturation in the column was monitored
using a dual gamma attenuation system.
The experiments were repeated for different
temperatures of hot water (10 -50 C), sand
types and flooding velocities. The data was
analyzed to determine the recovery
efficiencies. The research results from
these experiments will be used to design
mobilization experiments in two-dimensional
tanks to evaluate the recovery efficiencies in
more realistic field systems where the flow
is multi-dimensional and heterogeneities
control the flow behavior.
Keyword(s): ground water, NAPL, remediation, thermally enhanced recovery, up-scaling.
Oral presentation in non-aqueous phase liquids session.
The residual NAPL (non-aqueous phase
liquid) ganglia remain entrapped in the
saturated domain, posing a problem of
paramount importance in ground water
remediation. This paper addresses pumping
with either pulsed or monotonic
accelerations to recover trapped NAPL.
Laboratory tests were conducted on both
glass beads and sands to investigate the
mechanisms involved. The results reveal
that the durations of the accelerations are as
important as the magnitudes in causing
recovery. Though lower accelerations
induce lower viscous forces, they allow
unhindered transport of mobilized ganglia.
Higher accelerations on the other hand
result in sudden mobilization of a larger
population of ganglia, consequently
stranding them. The results are explained
using capillary number approach that
accounts for the effect of accelerations. The
results suggest that controlled accelerations
may be utilized for in situ recovery of
residually trapped NAPL ganglia. This study
provides a rational basis for implementation
of pulsed pumping in the field. Ongoing
studies are oriented towards optimizing the
pulse pumping parameters for maximal
recovery.
Keyword(s): NAPL ganglia, pulse pumping, pore fluid accelerations, capillary number.
Oral presentation in non-aqueous phase liquids session.
Recent studies have shown that
phytoremediation is an effective means of
reducing organic toxic compounds, such as
polynuclear aromatic hydrocarbons (PAHs).
However, little is known about the effect of
specific plant traits on phytoremediation
potential. Our objectives are to evaluate the
role of biological nitrogen fixation, fertilization
and their interactions in alfalfa (Medicago
Sativa L.) on the phytoremediation of pyrene
and benzo(a)pyrene in soil.
Experimental design was a 2 x 2 factorial
with 16 replications. Four replications were
destructively sampled at 3, 6, 9 and 12
months. Alfalfa varieties (representing
nitrogen fixation levels) and fertilization
levels were the variables, and an
unvegetated control was included. Alfalfa
varieties “Saranac” and “Ineffective
Saranac” were utilized in the study. The two
varieties are genetically and phenotypically
identical except for nitrogen fixing capability.
Saranac is capable of nitrogen fixation while
Ineffective Saranac is not. Two levels of
supplemental N, 0 and 50 lbs/acre, were the
second factor. Three seedlings were
germinated in each pot of an agricultural soil
contaminated with pyrene and
benzo(a)pyrene at initial concentrations of
100 ppm and 50 ppm per kilogram soil,
respectively. Degradation of pyrene and
benzo(a)pyrene were monitored by
destructive soil sampling at 3, 6, 9 and 12
months. Results (3 month) indicate that no
significant difference exist between N-
fixation level or fertilization level for pyrene
and benzo(a)pyrene degradation. In addition,
there is no difference between the
unvegetated control and treatments. Early
sampling indicates little difference between
vegetated and unvegetated tests. It is
expected that at 6, 9 and 12 month sampling
times, significant differences between
treatments will emerge.
Keyword(s): phytoremediation, nitrogen fixation, fertilization, alfalfa, PAHs, hazardous wastes.
Oral presentation in phytoremediation session.
In subsurface water systems, cationic
contaminants such as plutonium are often
adsorbed to soil particles because most soil
particles are negatively charged. Those
contaminants are mobilized only through the
transport of colloids. In the vadose zone, soil
interstitial water moves normally in fine
pores rather than in coarse pores due to the
capillary force. Moving in fine pores, colloids
are easily coagulated, filtered and then are
less mobile. However, preferential flow
through continuous macropores such as
earth worm holes have been observed and
investigated for decades. Such preferential
flow, if it occurs, will transport colloids much
more easily and rapidly into the deep soil
horizons and the ground water system.
Preferential flow through a vertical cylindrical
macropore was simulated at the monolith
scale using a two-dimensional finite element
method. Preferential flow in the macropore
is coupled with the flow in the soil matrix.
Flow in the macropore is mainly controlled
by surface ponding, flow loss to the soil
matrix around the macropore or lateral
infiltration, and the macropore size. Flow in
the soil matrix is simulated by the Richards
equation. A constant colloid concentration
was assumed when the flow enters the
macropore. The colloid transport in the
macropore and in the soil matrix was then
simulated using the computed flow field in
both the macropore and the soil matrix. The
colloid flux from the macropore is assumed
to be controlled mainly by the combination of
five factors. The first is the lateral infiltration
rate through the macropore wall. The
second factor is the ratio of the pore size in
the soil matrix to the colloid size. A small
ratio will cause the colloid coagulation in the
soil matrix near the macropore and
decrease the further transport of colloids
and the lateral infiltration rate. The third
factor is saturation of the soil matrix around
the macropore. Water moves in larger pores
when saturation is higher. The fourth factor
is the flow velocity in the macropore. Higher
velocity moves more colloids into a deeper
part of the macropore. The last is the
cumulative amount of colloids generated
through a unit length of the macropore wall.
This factor is similar to the second factor.
The sensitivity analysis was performed for a
hypothetical single macropore monolith, and
quantitative results were obtained.
Keyword(s): colloid transport, macropores, preferential flow.
Oral presentation in fate and transport session.
The development of remediation
technologies poses a serious challenge for
certain classes of compounds, such as
polycyclic aromatic hydrocarbons (PAHs).
These compounds are hydrophobic and,
therefore, readily sorb onto soil. The
available technologies, e.g., pump-and-treat,
are inefficient for treating hydrophobic
compounds because of their low solubilities.
A promising approach for circumventing this
difficulty is to solubilize such compounds by
adding surfactants.
A model has been derived for the system
implementing simultaneously the pump-and-
treat and rhizosphere technologies for
remediating a hydrophobic contaminant. The
model is comprised of two zones, the
aquifer and rhizosphere, in which all
participating material species are uniformly
distributed; the contaminant is flushed with
an aqueous surfactant solution from the
former zone to the latter. The model takes
into account dissolution, sorption and
biodegradation of the contaminant in the
aquifer zone under the assumption that local
equilibrium prevails; it also takes into
account sorption, mineralization and plant
uptake in the rhizosphere zone under the
assumption that mineralization obeys
Monod's kinetics. Simulation has been
performed with the model to determine the
effects of surfactant concentration in
enhancing the contaminant removal, the
number of flushings to remove the
contaminant from the aquifer zone, and the
time required to degrade the contaminant in
the rhizosphere zone.
Keyword(s): hydrophobic contaminant, remediation, rhizosphere, surfactant.
Poster presentation.
Phytoremediation is an emerging technology
for contaminated sites that is attractive due
to its low cost and versatility. It is a form of
ecological engineering that has proven
effective in several full-scale applications of
shallow contaminated sites. Plants have the
ability to withstand greater concentrations of
organic pollutants than most
microorganisms, and they can take up
chemicals quickly and convert them to less
toxic metabolites. In addition, they stimulate
degradation of organic chemicals in the
rhizosphere by root exudates, enzymes, the
build-up of organic carbon in the soil, and
the enrichment of rhizosphere microbial
communities.
In this paper, the direct uptake of organic
chemicals by plants and enzyme activity,
both within the plants and from exudates,
will be discussed. Nitroreductase,
dehalogenase, laccase, peroxidase and
nitrilase activity have been examined for a
number of plant species at the EPA
Environmental Research Laboratory in
Athens, Georgia. Full scale applications of
hybrid poplar trees have been used by
investigators at The University of Iowa to
take up excess nutrients and atrazine in
agricultural runoff, to close and cap landfills,
and to treat landfill leachate. Trinitrotoluene
(TNT) and ammunition wastes are a
candidate for remediation using this
technology.
Keyword(s): phytoremediation, exudates, enzymes, plants, organics.
Oral presentation in phytoremediation session.
Several bioreactor configurations have been
employed in experimental studies
addressing the aerobic cometabolism of
chlorinated solvents such as trichloroethene
(TCE). Application of these reactors is
primarily for the treatment of contaminated
ground water extracted during remediation.
Basically, these reactors can be classified
as either suspended or biofilm type and as
either continuous or intermittent operation.
This paper will examine how the reactor
configuration impacts the predicted
performance for different applications, as
measured by degree of TCE removal and
TCE destruction rate per unit volume of
reactor. Design methodology based on
underlying kinetic principals of
cometabolism, such as enzyme competition
and endogenous decay, will be developed.
The impact of microorganism type,
substrates, growth requirements and media
type on reactor performance will be
addressed.
Keyword(s): design, bioreactor, trichloroethene, ground water, remediation.
Oral presentation in technology transfer session.
Herbicides have been detected with
increasing frequency in ground water
supplies throughout the United States.
Some of these compounds mineralize
readily and others may persist for some
time. During herbicide degradation, products
are formed; some of these could be
environmental hazards. These metabolites
may also be short-lived and subsequently
degraded, or they may persist in the
environment. The behavior of these
herbicides and their products becomes
increasingly important as herbicide use
increases. Alachlor, a commonly used
herbicide, is known to be biodegradable to
varying degrees under various electron
acceptor conditions (aerobic, denitrifying,
sulfate reducing and methanogenic)
depending on experimental conditions and
the organisms present. Alachlor is a
suspected human carcinogen. Of 6 million
wells surveyed in 1987,1% contained
alachlor residuals, with 1200 of these wells
exceeding the maximum contaminant level
of 2 mg/l as set by the Environmental
Protection Agency. A survey of the literature
indicates that little documentation exists on
the degradation and transformation products
of alachlor.
Enrichment cultures were developed on
synthetic media under three terminal
electron acceptor conditions (denitrifying,
sulfate reducing and methanogenic). Under
denitrifying conditions with acetate-fed
organisms and resazurin (a color indicator
of redox potential) present, acetyl alachlor,
diethyl aniline, aniline and m-xylene were
positively identified as transformation
products of alachlor. Acetyl alachlor, a
reductive dechlorination product, and diethyl
aniline were expected metabolites. Aniline
and m-xylene, however, have not been
previously reported as metabolites of
alachlor under denitrifying conditions.
Aniline, a poison that poses a severe health
risk, and m-xylene, a compound that
damages the human nervous system, are of
particular concern. An abiotic reaction
mediated by resazurin was implicated in the
formation of these two compounds. On-
going research is focusing on the specific
role of resazurin and other electron carriers
in the production of these alachlor
metabolites. The goal is to determine which
transformation steps are biologically
mediated and which are abiotic. Acetyl
alachlor and diethyl aniline were also major
metabolites in sulfate-reducing and
methanogenic systems.
Keyword(s): alachlor, metabolites, biodegradation.
Poster presentation.
Prepared bed land treatment is a specific
bioremedial technology that is used to
decontaminate soils under unsaturated
conditions. A prepared bed is generally used
to remove contaminants from soil to reach
target remediation levels as well as to
prepare for ultimate disposal of soils for
protection of public health and the
environment. A prepared bed is managed
through nutrient and moisture addition; the
bed consists of a soil supporting
(foundation) layer, a liner, a leachate
collection system, and a monitoring system.
After soils have been decontaminated in a
prepared bed, the bed may be closed in
place by capping, or the cleaned soils may
be removed for ultimate disposal.
Guidance concerning the application of the
prepared bed bioremediation technology is
required by decision-makers responsible for
the clean-up of contaminated soils. Although
there is considerable information available
concerning soil bioremediation as a
treatment approach, there is currently no
technology transfer guidance specifically on
the use of prepared bed systems. Personnel
from Utah State University are providing the
technology transfer by developing a
guidance manual on the use of prepared
beds (in the first year); developing an
interactive computerized decision support
system based on the guidance manual (in
the second year); and then finalizing both
the guidance manual and decision support
software (during the third year) based on
user input and review.
Keyword(s): bioremediation, prepared bed, guidance manual.
Poster presentation.
Clays are widely used in the environmental
industry as impermeable barriers,
adsorbents, molecular sieves and for
stabilization of hazardous wastes.
Impermeable barriers using bentonite
include landfill liners and caps,
geocomposite liners, slurry walls, seals in
monitoring wells, and as barriers
surrounding radioactive waste canisters.
The common clay minerals identified include
smectite (bentonite), vermiculite, attapulgite
and sepiolite. These clays are especially
important because of their micron sized
particles, swelling properties (especially in
bentonite), large surface areas, high cation
exchange capacity, chemical stability,
charge distribution, unique atomic structure
and widespread occurrence.
Fundamentals of diffuse double layer,
mineral-surface-complexation and current
research in organo-clay complexation and
pillared clays with respect to hazardous
waste remediation will be discussed.
Results of analytical electron microscopy
(quantitative thin film X-ray microanalysis,
selected area electron diffraction) and X-ray
diffraction to characterize the chemical
composition and crystal structure of these
common clays will be presented.
Keyword(s): clays, remediation, atomic structure, microscopy.
Poster presentation.
A recent report on health assessment of
chlorinated dioxin has revealed a number of
health-related issues of these controversial
chemicals. The report states that dioxins,
even at very low levels, pose health risks to
humans. However, the report has given rise
to new controversies on source and
distribution of these chemicals in the
environment. It indicated that all the known
sources of dioxin account for only one-half
of the estimated total environmental burden.
The other half results from unknown
sources including perhaps natural
processes such as forest fires. While some
of the contentions on sources may be true,
one major reason for the discrepancy could
be transformation, especially
phototransformation in the atmosphere. This
is especially relevant to the environmental
concentration when expressed as toxic
equivalents (TEQ). Since, on this scale,
conversion of certain congeners to others
can lead to significant changes in TEQ
values; e.g., conversion of
octachlorodibenzo-p-dioxin to congeners
with lower chlorine substitution will lead to
an increase in TEQ value. A study to
examine this phenomena was undertaken.
Phototransformation of chlorinated dioxins
was examined in the vapor phase and on
aerosol particles.
The gas phase studies were carried out with
a two-dimensional gas chromatographic
(GC) system. Studies on dioxin-bearing
aerosol were carried out in a photoreaction
chamber coupled to an electrostatic
classifier and particle counter. These
arrangements permitted isolation and
irradiation of selected chlorinated dioxins in
the photoreactor for varied periods and
under different atmospheres. The irradiation
experiments revealed that degradation rates
in both the gas phase and on aerosol
particles are dependent on dioxin structure;
e.g. approximately 80% of 2,3,7-
trichlorodibenzo-p-dioxin was transformed
after a 20-minute irradiation while less than
30% of 2,3,7,8-tetrachlorodibenzo-p-dioxin
was transformed over the same exposure
period. Photodegradation rates decreased
with an increase in the number of chlorines.
Degradation rates were also influenced by
the position of chlorine substitutions. The
results showed that, in contrast to solution
phase studies, congeners with peri
chlorines photodegrade more rapidly than
congeners with laterally substituted
chlorines. Addition of selected dopants to
the photoreactor atmosphere effected
changes in reaction kinetics and formation
of hydrodehalogenation photoproducts. The
addition of 100 ppm hexane to the
photoreactor chamber enhanced formation
of neutral hydrodehalogenation
photoproducts. These photoproducts
provided further evidence of peri position
dehalogenatlon. Introduction of 100 ppm O2
or H2O to the photoreactor atmosphere
increased the photodegradation rate
significantly. The increase most likely results
from the formation of highly reactive O3 and
hydroxyl radicals. Surface area experiments
indicate that the reactions occur primarily in
the gas phase and not on the photoreactor
walls. An increase in the photoreactor
surface area did not yield a significant
increase in the photodegradation rate. All of
the above results indicate that in the gas
phase more toxic (laterally substituted)
congeners are more persistent than less
toxic (peri substituted) analogs and that less
toxic congeners can be phototransformed
into more toxic congeners by elimination of
peri substituted positions, thus increasing
the TEQ of irradiated samples.
Keyword(s): phototransformation, polychlorinated dibenzo-p-dioxin, chlorinated dioxin, toxic equivalents.
Oral presentation in chemical destruction session.
Our previous study of St. Lawrence River
sediments showed evidence for a varying
degree of in situ dechlorination at all sites
except the Reynolds 001 site. The absence
of dechlorination at this site seemed due
mainly to the presence of a “tar-like” non-
aqueous phase liquid (NAPL) associated
with PAH co-contamination, since PAH's
themselves, at concentrations comparable
to ambient levels, did not inhibit
dechlorination in laboratory experiments.
When river sediments were anaerobically
incubated in the laboratory for 17 months,
dechlorination continued in sediments from
the General Motors (GM) site; it was rapid
during the first 4 months, but leveled off with
little further dechlorination up to 17 months.
The average number of Cl's per biphenyl
decreased approximately 14% from 3.0
before incubation to 2.6, (or an overall 32%
reduction from the original Aroclor 1248).
When GM sediment microorganisms were
inoculated into PCB-free Grasse River
sediments spiked with Aroclor 1248,
dechlorination was similar. Thus, the
residual PCB level in these sediments may
represent the potential limit of in situ
dechlorination. The dechlorination products
were comprised mostly of dichloro- (66
mol%), trichloro- (24%) and tetrachloro-
(10%) congeners. In contrast, river
sediments from the Reynolds site did not
show any further dechlorination under
laboratory incubation. However, the Aroclor-
1248-spiked sediments inoculated with
Reynolds-site microorganisms showed
dechlorination similar to that found with GM
microorganisms in the same sediments.
These results demonstrated that despite
little in situ dechlorination, Reynolds
sediments contained competent
microorganisms and their overall
dechlorination competence seemed to be
similar to that of GM populations when
compared in the same type of sediments.
Taken together, however, the present study
shows that in situ can vary widely depending
on the prevailing sediment conditions.
Keyword(s): polychlorinated biphenyls (PCBs), reductive dechlorination, bioremediation.
Poster presentation.
Pesticides are applied to grasses on golf
courses, home lawns, sports complexes,
industrial parks and other areas to improve
turf quality. Current public concern has
focused attention on the environmental
effects of chemical applications to turfgrass
areas. The objective of this research was to
compare the leaching characteristics of
pendimethalin, chlorpyrifos, isazofos,
metalaxyl, 2,4-D, dicamba and MCPP when
applied to a Kentucky bluegrass turf
established on 50 cm undisturbed soil
columns. The macropore system in the soil
remained intact. This study was conducted
using a heavy and light irrigation regime. The
heavy irrigation regime consisted of four
2.54 cm applications spread over the four
week test period. The light irrigation regime
consisted of sixteen 0.63 cm applications
spread over the four week test period.
Isazofos, chlorpyrifos, metalaxyl,
pendimethalin, 2,4-D, dicamba and MCPP
recovery in the leachate from soil columns
under the heavy irrigation regime averaged
6.3, 0.5, 7.7, 0.2, 0.6, 0.1 and 0.0% of the
applied, respectively. Isazofos, chlorpyrifos,
metalaxyl, pendimethalin, 2,4-D, dicamba
and MCPP recovery in the leachate from soil
columns under the light irrigation regime
averaged 0.4, 0.0, 0.2, 0.0, 0.1, 0.0 and
0.0% of the applied, respectively. From this
research, it was concluded that irrigation
practices can have an impact on the
leaching of pesticides through soil profiles.
Keyword(s): environment, urban, insecticide, herbicide, fungicide.
Poster presentation.
Pesticides are applied to grasses on golf
courses, home lawns, sports complexes,
industrial parks and other areas to improve
turf quality. Current public concern has
focused attention on the environmental
effects of chemical applications to turfgrass
areas. The objective of this research was to
investigate the fate of pendimethalin,
chlorpyrifos, isazofos and metalaxyl when
applied to a Kentucky bluegrass turf
established on 50 cm undisturbed soil
columns. The macropore system in the soil
remained intact. This study was conducted
using a heavy and a light irrigation regime.
The heavy irrigation regime consisted of four
2.54 cm applications spread over the four
week test period. The light irrigation regime
consisted of sixteen 0.63 cm applications
spread over the four week test period. The
author conducted this research while in
graduate school at lowa State University.
Average isazofos, chlorpyrifos, metalaxyl
and pendimethalin recovery from soil
columns under the heavy irrigation regime,
plus that collected in the leachate, averaged
8.8,11.5, 23.8 and 7.9%, respectively.
Isazofos, chlorpyrifos, metalaxyl and
pendimethalin recovery from soil columns
under the light irrigation regime, plus that
collected in the leachate, averaged 3.4, 6.6,
13.9 and 4.6%, respectively. On average
6.3, 0.5, 7.7 and 0.2% of the applied
isazofos, chlorpyrifos, metalaxyl and
pendimethalin, respectively, were found in
leachate from undisturbed soil columns
under the heavy irrigation in contrast to 0.4,
0.0, 0.2 and 0.0% from undisturbed soil
columns under the light irrigation. From this
research, it was concluded that irrigation
practices can have an impact on the
movement of pesticides through soil
profiles.
Keyword(s): environment, urban, insecticide, herbicide, fungicide.
Oral presentation in phytoremediation session.
Soil factors reduce the rate and amount of
mineralization of pyrene by Phanerochaete
chrysosporium. Soils from different
geographic locations with different
compositions all showed reduced amounts
of pyrene mineralization by P.
chrysosporium when compared to a non-
soil system. Two clay types differentially
decreased the transformation of pyrene by
P. chrysosporium. Artificial soils produced
with different physical compositions of sand,
silt and clay indicated that inhibition
increases with higher silt percentages. Sand
had little effect on mineralization
performance. Biotic factors also influence
mineralization of pyrene in soil. Bacteria,
found to be antagonistic to the growth of P.
chrysosporium by plate assays, inhibit
mineralization of pyrene in sterile soil.
Colony-forming units of antagonistic bacteria
decreased over time in conjunction with a
decrease in soil pH caused by P.
chrysosporium. These facts suggest that
both biotic and abiotic factors must be
investigated for each soil to be considered
for bioremediation using P. chrysosporium.
This research supported by the NIEHS Superfund grant.
Keyword(s): mineralization, soils, antagonism.
Poster presentation.
Correlations of soil characteristics with
relative rates of pesticide degradation often
fail when multiple soil types are studied. Our
objective was to provide a variety of soils
with the same population of atrazine-
degrading microbes and correlate
degradation rates with soil characteristics.
Soils from profiles of a Sharpsburg silty clay
loam (Typic Argiudoll), Ortello sandy loam
(Udic Haplustoll) and Hord silt loam (Pachic
Haplustoll) were inoculated with surface soil
of a Hord silt loam that had a history of
atrazine [6-chloro-N-ethyl-N'-(1-
methylethyl)-1,3,5-triazine-2,4-diamine]
application and a demonstrated capacity for
enhanced atrazine mineralization.
Experiments were performed by static
incubation of 25 g soil maintained at 22 C
and -50 kPa water content. Treatments
included soils (type and horizon) that were
either inoculated or uninoculated. Unlabeled
and 14C-ring labeled atrazine were applied to
yield an initial concentration of 3.2 mmol kg-1.
14CO2 was trapped in 15 mL of 0.5 N NaOH
and activity determined by scintillation
counting. 14CO2 samplings occurred every 7
to 10 d for 80 d. In addition, samples from
each soil-horizon combination were frozen
every 20 d and extracted with CH3OH for
determination of atrazine and degradates.
Bound (unextractable) residue was
determined by biological oxidation to 14CO2
for mass balance determinations. Atrazine
degradation and mineralization rates were
correlated to soil properties. Results
indicated that inoculated soils generally
produced higher rates of atrazine
degradation and mineralization. Degradation
and mineralization among inoculated soils
were found to correlate (either positively,
negatively or variably) with atrazine
adsorption coefficients (Kd) and soil
properties such as NO3-N, P, and organic C
concentrations and pH. We also observed
that some soils, in particular those with high
pH, did not show increased mineralization
when inoculated. These results illustrate the
importance of both soil characteristics and
the presence of specific microbial
populations on atrazine degradation in soil.
Keyword(s): atrazine, degradation, soil characteristics, microbial populations.
Poster presentation.
The available methods for reaction path or
network synthesis are incapable of directly
taking into account the generation of
hazardous substances. A novel method is
introduced here to alleviate this deficiency; it
prevents the occurrence of unwanted
chemical species, e.g., hazardous
substances, in a reaction network from the
outset of its synthesis. This method, based
on the combinatorial technique originally
developed for process synthesis, can
generate reaction paths satisfying either of
the following requirements: (1) no by-
products are hazardous, and (2) no
hazardous substances are involved. For
either case, the maximum reaction network
is constructed first, which, in turn, gives rise
to a set of all feasible reaction networks or
paths. The efficacy of the method has been
demonstrated with a realistic example.
Keyword(s): reaction network, hazardous substances, synthesis.
Oral presentation in pollution prevention/waste minimization.
Carbon tetrachloride (CT) and chloroform
(CF) are common ground water
contaminants. Products of CT and CF
biotransformation by mixed, methanogenic
cultures include the less-chlorinated
homologues, CF and dichloromethane
(DCM), respectively, and carbon dioxide.
The microbial transformation of CT and CF
may involve trichloromethyl and
dichloromethyl radicals, respectively. The
binding of these radicals to cellular lipids and
proteins accounts, in part, for the toxicity of
CT and CF in mammalian systems. It is
possible that CT- or CF-biotransforming
microorganisms may be harmed by these
radicals in a similar manner. Parallel
reasoning has been offered for the
inactivation of methanotrophic cells by TCE
transformation: TCE epoxide, a toxic,
reactive, known TCE metabolite in
mammals may also be produced by
methanotrophs, resulting in the loss of
methanotrophic activity following TCE
transformation. The objective of this work
was to determine the toxicity associated
with the transformation of CT and CF by a
methanogenic consortium.
An acetate-enriched, mixed, methanogenic
culture having a volatile suspended solids
(VSS) concentration of 220 mg/L was used
as a source of organisms. Experiments
were conducted in 38 mL serum bottles
using 25 mL cell suspension. Following the
biotransformation of CT or CF, bottles were
stripped with N2/CO2 (80/20 v/v) gas to
remove residual volatile compounds. The
methanogenic activity of the consortium
decreased 11% and 24% per 100 nmol of
CT or CF transformed, respectively,
corresponding to the inactivation of 5 and 14
mg VSS of methanogenic biomass per mmol
CT or CF transformed, respectively. Control
experiments determined that the inactivation
of methanogenic bacteria did not result from
inhibition by a nonvolatile CT- or CF-
metabolite, nor to exposure to DCM. Data
analysis showed that the observed
inactivation was independent of the
maximum CT or CF concentration over the
ranges studied and the time-integrated CT
or CF dose.
Keyword(s): inactivation, methanogens, carbon tetrachloride, chloroform.
Oral presentation in bioremediation session.
Several recent studies have shown that
chlorinated aliphatic hydrocarbons (CAHs)
may be reduced by metallic iron. These
studies have focused on abiotic processes,
while limited attention has been given to
combined microbial and abiotic
dechlorination. Methanogenic bacteria can
use metallic iron as an energy source by
coupling the anodic dissolution of iron, which
is an otherwise unfavorable reaction, with
the consumption of water-derived H2, which
is a very thermodynamically favorable
reaction:
4Fe0 + 8H+ ® 4Fe2+ + 4H2 DG0' = +3.5 kJ
4H2 + CO2 ® CH4 +2H2O DG0' = -139 kJ
4Fe0 + 8H+ + CO2 ® 4Fe2+ + CH4 + 2H2O DG0' = -135.5 kJ
The microbial transformation of CAHs has
been observed in pure and mixed
methanogenic cultures. Hence, under
methanogenic conditions in the presence of
zero-valent iron, two degradation
mechanisms may be important: Fe(0) may
reduce CAHs abiotically, and Fe(0) may
indirectly reduce CAHs via
biodehalogenation. In light of this, we
investigated the transformation of carbon
tetrachloride (CT), chloroform (CF) and
dichloromethane (DCM) in methanogenic
incubations amended with iron metal.
An acetate-enriched, mixed, methanogenic
culture having a volatile suspended solids
(VSS) concentration of 220 mg/L was used
as a source of organisms. Experiments
were conducted anaerobically in duplicate at
20 C using 25 mL liquid volume in 38 mL
serum bottles. Resting (unfed) cells were
used in incubations containing cell
suspension. Experiments examined the
transformation of CT, CF and DCM in
bottles containing (1) iron and cell
suspension, (2) cell suspension only, and
(3) iron in cell-free supernatant. For CT and
CF, the value of the pseudo-first order rate
constant, k, for the iron-cell (IC) treatments
was significantly greater than k for the iron-
supernatant (IS) and resting cell (RC)
treatments, respectively. DCM was not
transformed. Analysis of the rate coefficients
also revealed that the interaction between
cells and iron was synergistic with regard to
CT and CF degradation. The increased CT
and CF transformation kinetics in treatment
IC may be due to cometabolism by
hydrogen-oxidizing methanogens. Methane
production was negligible in bottles
containing cell suspension only, or in bottles
containing iron and cell-free supernatant.
Methane production was observed,
however, in CT- and CF-free bottles
containing iron and cell suspension.
These experiments indicate that
methanogens coupled the biocorrosion of
iron metal and biodehalogenation of CT and
CF via cometabolism, with water-derived
hydrogen acting as energy source. Further
work is required to investigate if the results
observed here are sustainable in flow-
through environments.
Keyword(s): iron, cometabolism, hydrogen, methanogens, biocorrosion.
Oral presentation in bioremediation session.
Contamination of soil by polycyclic aromatic
hydrocarbons (PAHs) is of considerable
importance because of their carcinogenic
and mutagenic potential. PAHs are non-
polar hydrophobic organic compounds
characterized by two or more fused
benzene rings in various arrangements.
Although these compounds occur
ubiquitously, the primary source to the
environment is anthropogenic activity,
particularly through the incomplete
combustion of petroleum hydrocarbons. As
a result, PAHs can be highly sorbed to soil
organic matter, thus making remediation
difficult. Recent evidence suggests the
potential exists for enhanced biodegradation
of toxic organic compounds in the presence
of rhizosphere soil due to increased
indigenous microbial activity and root
exudations. The study utilizes three soil
types: sterile, rhizosphere and non-
rhizosphere. The soils were amended with
anthracene and pyrene at concentrations of
100 ppm and were placed in small
bioreactors in quadruplicate. Two
amendments were added daily to the soils,
with half the bioreactors receiving 0.01 M
calcium chloride solution, while the
remaining reactors received an organic acid
mixture simulating root exudation in the
rhizosphere. The soil treatments were
maintained at optimum water content. The
bioreactors were disassembled at
predetermined times over a 56 day period
and a mass balance was performed using
gas chromatography.
Keyword(s): polycyclic aromatic hydrocarbons, rhizosphere, biodegradation.
Oral presentation in phytoremediation session.
Significant pentachlorophenol (PCP)
degradation occurred within two weeks
when either FX66 (a non-Phanerochaete
WRF) or Phanerochaete chrysosporium
were added to soil from wood treatment
sites in Montana (550 ppm PCP) and in
Minnesota (600 ppm PCP). The best results
occurred in soil incubations with added
FX66 (84% PCP degradation in Minnesota
soil and 72% in Montana soil). The Montana
soil (79% sand, 13% silt, 9% clay) was also
contaminated with arsenic (45 ppm) and
copper (165 ppm). The Minnesota soil (70%
sand, 20% silt, 10% clay) allowed better
fungal growth. Pentachloroanisole (PCA)
appearance inversely correlated with PCP
disappearance in both soils incubated with
P. chrysosporium. However, neither PCA,
tetra nor trichlorophenols were detected by
GC analysis (EPA method 8040) in samples
incubated with FX66 or in indigenous
controls. Extensive PCP degradation
occurred with indigenous incubations (65%)
in the Minnesota soil but was negligible in
the Montana soil. Incubations were done in
triplicate vials at 25 C with 10 grams of soil.
Additions of the solid culture/sawdust
mixtures increased the soil volume by 33%,
which was taken into account when PCP
degradation was evaluated. Larger scale
incubations (1 cubic foot of soil) with FX66
showed a 56% decrease in PCP in the
Montana soil within 45 days. These results
indicate that fungal remediation of PCP-
contaminated soils should be evaluated in
field trials.
Keyword(s): white-rot fungi, PCP degradation, soil.
Poster presentation.
Increased public awareness of ground water
contamination by industrial and agricultural
chemicals has created increased attention
on the issue of solute movement through
soils. This heightened awareness is piqued
when models underestimate the transport
rate of compounds in question. Most field
solute-transport models use a simplified
form of the convective-dispersion equation.
Attempts to estimate retardation factors and
dispersion coefficients used in convective-
dispersion equations are complicated by the
spatially variable values obtained in
structured soils. Additionally, attempts to
model field-scale solute transport are
usually expensive and exacerbated by
climatic conditions not in the control of the
researcher. Alternatively, when large cores
are used in transport studies, considerable
numbers of samples are often generated. In
this study we constructed an automated
sampling system for large soil columns and
compared results to a continuous sampling
method (vacuum chamber and fraction
collector). Our objectives were to determine
if there were statistical differences between
the two methods and demonstrate the
advantages of the automated sampling
system. The automated system consisted
of three solenoid values that periodically
switched column effluent from a waste
receptacle to a sampling vial. Intact soil
columns were obtained from the field by
slowly pushing a polyvinyl chloride (PVC)
tube (0.15 m ID) into the ground and
extracting the core. The pipe with soil was
secured at both ends using acrylic caps,
with the bottom cap sealed with O-rings. A
constant 23 kPa suction was applied to the
bottom of the column. Columns receive
approximately one pore volume 3mM CaCI2-
3H20 at a constant pore water velocity.
Results indicated apex concentrations
(C/C0) were between 0.64 and 0.68 of initial
pulse concentrations of 4000 dpm mL-1;
similar breakthrough curves were observed
from both sampling methods. These results
indicate the automated collection system
can be effectively used in large column
transport studies and provides additional
advantages by reducing sample size
(numbers) and time required for sample
collection.
Keyword(s): ground water quality, solute transport.
Poster presentation.
The organic wood treatment chemicals
(creosotes, chlorinated phenols and
associated chlorinated dioxins) are highly
toxic and persistent environmental
contaminants. The only widely accepted
technology for destruction of these
contaminants in soil is high temperature
incineration. This technology, however, is
very expensive and meeting increased
public resistance.
A study to explore effective, low-cost
alternative decontamination techniques is
underway in our laboratory. One promising
technique involves removal of contaminants
with suitable solvents/surfactants,
photodegradation of contaminants and,
finally, removal of residual contaminants
from solvent with activated carbon.
The present report deals with laboratory
experiments designed to enhance
photodegradation efficiencies of polynuclear
aromatic hydrocarbons (PAHs), chlorinated
phenols, and, in particular, the
polychlorinated dibenzo-p-dioxins (PCDDs).
All irradiation experiments were conducted
in the near UV and visible regions.
Enhancements resulting from the presence
of suspended (solgels) and/or immobilized
semiconductor photocatalysts were
monitored. In addition, effects of
homogeneous photocatalysts, i.e., free
radical initiators such as hydrogen peroxide
(H2O2) and organic peroxide, were also
monitored. The results obtained showed that
the presence of photocatalysts leads to a
significant increase in photodegradation
efficiencies. The higher efficiencies were
achieved in solutions which contained
homogeneous and heterogeneous catalysts.
The highest transformation efficiency was
achieved with titanium oxide (TiO2) and
H2O2. Quantum yields in the presence of
these catalysts was approximately 50 times
higher than in solutions devoid of these
materials.
The results of field experiments showed that
soil decontamination can be obtained by
coupling solvent wash with
photodegradation. The most promising
results were obtained with the use of binary
solvent mixtures, and up to 95% of
polychlorinated dibenzo-p-dioxins were
removed from the soil. The technique with
efficient solvent recovery and reuse should
provide an economical option for
remediation of contaminated soils at wood
treatment sites. Detailed results for removal
and destruction of major contaminant
classes will be presented.
Keyword(s): photodegradation, soil, wood treatment.
Oral presentation in chemical destruction session.
In situ bioremediation is a process by which
contaminants in subsurface environments
are biologically eliminated or mineralized;
however, it is often difficult to implement.
Microbes sparsely distributed in deep soils
are incapable of degrading a chemical with
significant speed; furthermore, fine-pore
structures of soils tend to retard the
penetration and propagation of these
microbes and to hinder oxygen transfer. The
latter is particularly detrimental to the
aerobic growth of microbes, which is
essential for bioremediation. Measures
intended to promote bioremediation, such as
addition of surfactants for enhancing
dissolution and application of genetically
engineered microbes for accelerating the
biodegradation of the contaminants, are
almost impossible to adopt. This is
attributable to the fact that various facets of
the bioremediation process, e.g., distributing
the dissolved contaminants, enriching the
oxygen content, and concentrating the
microbes, cannot be readily manipulated.
The present work proposes a novel
technology, namely, bio-wall. This
technology resorts to an in situ constructed
medium with porosity and organic content
greater than those of the original soil for
promoting the adsorption and retention of
microbes and the biodegradation of
contaminants. Moreover, oxygen and
nutrient are supplied to the bio-wall to
facilitate microbial growth. The results of a
conceptual design study and simulation
have revealed that the technology is indeed
feasible and, under certain environmental
conditions, cost-effective. Particularly
noteworthy is the fact that the bio-wall can
prevent contaminant migration through
enhancement of the biodegradation rate and
reduction of the plume-distance, both by
several orders of magnitude.
Keyword(s): bio-wall, remediation, soil, ground water.
Poster presentation.
Experiments were conducted to investigate
the fate of ethylbenzoate and soil
microorganisms in shallow aquifers.
Biodegradation and volatilization have been
identified to be the major mechanisms in
attenuating ethylbenzoate. The parameters
of an available model have been obtained by
fitting it to the experimental data. Various
facets of biodegradation, including the
effects of mass transfer resistance and
initial distribution of microorganisms, have
been numerically analyzed on the basis of
the model.
Keyword(s): bioremediation, aquifer, volatilization, mass transfer.
Oral presentation in bioremediation session.HERBICIDE DEGRADATION BY
RHIZOSPHERE MICROBIAL
COMMUNITIES
Todd A. Anderson, Ellen L. Kruger and Joel R. Coats,
Pesticide Toxicology Laboratory, Iowa State
University, Ames, IA, 50011-3140, 515-294-8667ESTIMATION OF SOIL HYDRAULIC
PROPERTIES FROM PARTICLE SIZE
DISTRIBUTION USING ARTIFICIAL
NEURAL NETWORKS (ANNs)
J. Anmala and R.S. Govindaraju, Department of Civil
Engineering, Kansas State University, Manhattan,
KS, 66506, 913-532-1585BIODEGRADATION AND
DISSIPATION OF POLYCYCLIC
AROMATIC HYDROCARBONS IN
SOIL RHIZOSPHERE
M. Arunachalam1, M.K. Banks1 and A.P. Schwab2,
1Department of Civil Engineering and 2Department of
Agronomy, Kansas State University, Manhattan, KS,
66502, 913-532-1573PHYTOREMEDIATION OF
PETROLEUM CONTAMINATED SOIL:
A TECHNOLOGY TRANSFER
PROJECT
M.K. Banks1, A.P. Schwab2 and R.S. Govindaraju1,
1Department of Civil Engineering, Kansas State
University, Manhattan, KS, 66506 and 2Department
of Agronomy, Kansas State University, Manhattan,
KS 66506LEAD AND CADMIUM SPECIATION IN
SMELTER-CONTAMINATED SOIL
Matt Bergers and Thomas Harris, Department of
Chemistry, University of Tulsa, Tulsa, OK, 74104-
3189, 918-631-3090INNOVATIVE, ENVIRONMENTAL
REMEDIATION TECHNOLOGIES
DEVELOPED BY AN ACADEMIA/
GOVERNMENT/INDUSTRY
PARTNERSHIP
R. Bhada, R. Jacquez and A. Ghassemi, Waste-
Management Research Consortium, New Mexico
State University, P.O. Box 30001, Las Cruces, NM,
88003, 505-646-2038REMEDIATING RDX-CONTAMINATED
SOIL AND WATER BY FENTON
OXIDATION AND METAL-REDUCTION
Eleanor L. Bier, Jasbir Singh, S.D. Comfort and P.J.
Shea, University of Nebraska, Lincoln, NE, 68583-
0915, 402-472-1503COMBINED EFFECT OF PORE FLUID
DYNAMICS AND COMPOSITION ON
STABILITY OF PARTICULATE
CONTAMINANTS
Mohan V.S. Bonala, Rao V.V.S.R. Poduri and
Lakshmi N. Reddi, Department of Civil Engineering,
Kansas State University, Manhattan, KS, 66506, 913-
532-1586CHARACTERIZATION OF LEAD
CONTAINING MINING AND SMELTER
WASTE
S.R. Burckhard1, A.P. Schwab2 and M.K. Banks1,
1Department of Civil Engineering, Kansas State
University, Manhattan, KS, 66506, 913-532-5862,
and 2Agronomy Department, Kansas State
University, Manhattan, KS, 913-532-7213CELLS ON ROTATING FIBERS
R. Clyde, Clyde Engineering, P.O. Box 740644, New
Orleans, LA, 70174, 504-362-7929BIOREMEDIATION OF EXPLOSIVES
CONTAMINATED SOILS: A STATUS
REVIEW
H.D. Craig1, W.E. Sisk2, M.D. Nelson3 and W.H.
Dana4, 1U.S. Environmental Protection Agency
Region 10, Oregon Operations Office, 811 SW 6th
Avenue, Portland, OR, 97204, 503-326-3689; 2U.S.
Army Environmental Center, Aberdeen Proving
Ground, MD, 21010-5401, 410-612-6851; 3Seattle
District Corps of Engineers, 4735 E. Marginal Way S.,
Seattle, WA, 98124-2255, 206-764-3458; and
4Oregon Department of Environmental Quality,
Waste Management and Cleanup Division, 811 SW
6th Avenue, Portland, OR, 97204, 503-229-6530MOMENT ANALYSIS TO ESTIMATE
DEGRADATION RATE CONSTANTS
FROM LEACHING EXPERIMENTS
B.S. Das and G.J. Kluitenberg, Department of
Agronomy, Kansas State University, Manhattan, KS,
66506, 913-532-7215THE EFFECT OF TRANSITION METAL
COATINGS ON THE ABILITY OF
CALCIUM OXIDE TO
DESTRUCTIVELY ADSORB CARBON
TETRACHLORIDE
Shawn Decker1 and Kenneth J. Klabunde2,
Department of Chemistry, Kansas State University,
Manhattan, KS, 66506, 1913-532-6829 and 2913-
532-6849SELECTION AMONG TREATMENT
OPTIONS FOR REMOVING SOCS
FROM WATER
B.I. Dvorak, Department of Civil Engineering, W348
NH, University of Nebraska-Lincoln, Lincoln, NE,
68588-0531, 402-472-3431CHEMICAL ANALYSES: HOW TO GET
THEM DONE RIGHT (CUSTOMER-
ANALYST INTERACTIONS)
Mitchell D. Erickson, Argonne National Laboratory,
Argonne, IL, 60439TWO-DIMENSIONAL SURFACTANT
ENHANCED DISSOLUTION OF NON-
AQUEOUS PHASE LIQUIDS
John E. Ewing1 and Tissa H. Illangasekare2,
Department of Civil Engineering, University of
Colorado at Boulder, Boulder, CO, 80309, 1303-492-
6754 and 2303-492-6644CONVERSION OF SCRAP TIRES TO
ACTIVATED CARBON AND ITS
APPLICATION FOR TREATMENT OF
ORGANIC WASTE
V. Flanigan, S. Kapila, K.S. Ryoo and W.W. Delp,
Center for Environmental Science and Technology,
University of Missouri-Rolla, Rolla, MO, 65401INFLUENCE OF A FLUCTUATING
WATER TABLE ON MICROBIAL
DEGRADATION OF PESTICIDES
T.J. Freeborn, M.K. Banks, R.S. Govindaraju, C. Rice
and A.P. Schwab, Department of Civil Engineering,
Kansas State University, Manhattan, KS, 66506, 913-
532-5862REMOVAL OF A MIXTURE OF
IMMISCIBLE LIQUIDS BY IN-WELL
AIR SPARGING
Prashant Gandhi1, L.E. Erickson2 and L.T. Fan2,
1TapanAm Associates, Inc., 8010 State Line,
Leawood, KS, 66208 and 2Department of Chemical
Engineering, Kansas State University, Manhattan,
KS, 66506, 913-532-5584UPTAKE OF COPPER IONS FROM
SOLUTION BY DIFFERENT
VARIETIES OF MEDICAGO SATIVA
(ALFALFA)
J.L. Gardea-Torresdey, K.J. Tiemann and J.H.
Gonzalez, Department of Chemistry, University of
Texas at El Paso, El Paso, TX, 79968, 915-747-5359COPPER ADSORPTION BY
SPHAGNUM PEAT MOSS AND ITS
DIFFERENT HUMIC FRACTIONS
J.L. Gardea-Torresdey and L. Tang, Department of
Chemistry, The University of Texas at El Paso, El
Paso, TX, 79968, 915-747-5359ABILITY OF MEDICAGO SATIVA TO
UPTAKE NICKEL IONS FROM
AQUEOUS SOLUTIONS
Jorge L. Gardea-Torresdey, Jorge H. Gonzalez and
Kirk Tiemann, University of Texas at El Paso, El
Paso, TX, 79968, 915-747-5359COPPER BINDING BY MUCOR
ROUXII GROWN IN THE PRESENCE
AND ABSENCE OF COPPER IONS
J.L. Gardea-Torresdey1, I. Cano-Rodríguez1 and F.
Gutiérrez-Corona2, 1Department of Chemistry,
University of Texas at El Paso, El Paso, TX, 79968,
915-747-5359 and 2Instituto de Investigación en
Biologia Experimental (IIBE), Chemistry School,
University of Guanajuato, Guanajuato, Gto., 36000,
MexicoMETHOD DEVELOPMENT AND
DETERMINATION OF TIN IN THE
MARINE ENVIRONMENT OF LA PAZ,
B.C.S., MEXICO, USING ATOMIC
ABSORPTION SPECTROSCOPY
(AAS)
J.L. Gardea-Torresdey, S. Martinez-Gonzalez and
K.H. Pannell, Chemistry Department, University of
Texas at El Paso, El Paso, TX, 79968, 915-747-5316AEROBIC BIOTRANSFORMATION OF
2,4,6-TRINITROTOLUENE (TNT) BY
PSEUDOMONAS FLUORESCENS
P.C. Gilcrease and V.G. Murphy, Department of
Chemical and Bioresource Engineering, Colorado
State University, Fort Collins, CO, 80523, 303-491-
5252FATE AND TRANSPORT MODEL OF
TNT CONTAMINATED SOILS
J.C. Gillen, J.C. Tracy and M.S. Kennedy, Northern
Great Plains Water Resources Research Center,
South Dakota State University, Brookings, SD,
57007, 605-688-5427MODELING OVERLAND FLOW
CONTAMINATION OF CHEMICALS
MIXED IN SHALLOW SOIL HORIZONS
Rao S. Govindaraju and L.E. Erickson, Kansas State
University, Manhattan, KS, 66506, 913-532-1585SPATIAL VARIABILITY OF SURFACE
INFILTRATION PROPERTIES OVER
TWO FIELDS IN THE KONZA PRAIRIE
Rao S. Govindaraju, J.K. Koelliker, A.P. Schwab and
M.K. Banks, Kansas State University, Manhattan, KS,
66506, 913-532-1585USE OF GEOSTATISTICS IN
DESIGNING AND ANALYZING
TREATMENT EFFECTS AT THE
FIELD SCALE
Rao S. Govindaraju, M.K. Banks and A.P. Schwab,
Kansas State University, Manhattan, KS, 66506, 913-
532-1585MACROPORE FLOW AT THE
COLUMN SCALE: EXPERIMENTAL
METHODS AND MODEL
CALIBRATION
B.P. Greimann1, R. Huanxiang1, T.H. Illangasekare1
and M. Litaor2, 1Department of Civil Engineering,
University of Colorado at Boulder, Boulder, CO,
80309 and 2EG&G, Rocky Flats Environmental
Technology Site, Golden, CO, 303-966-8583THE NAOMI PROGRAM AND HERS:
WORKING TO CREATE LASTING
LINKS
W.M. Griswold1, G.L. Godfrey1, S.C. Grant2 and D.L.
Tillison1, 1Haskell Indian Nations University,
Department of Natural and Social Sciences, 155
Indian Avenue, Box 1227, Lawrence, KS, 66046 and
2Great Plains-Rocky Mountain Hazardous
Substance Research Center, Kansas State
University, 101 Ward Hall, Manhattan, KS, 66506-
2502EFFECT OF CITRATE ON THE
ADSORPTION OF ZINC TO SOIL
Y. He1, A.P. Schwab2 and M.K. Banks1, 1Department
of Civil Engineering and 2Department of Agronomy,
Kansas State University, Manhattan, KS, 66506USING FOURIER TRANSFORM
INFRARED (FT-IR) SPECTROMETRY
TO MONITOR BIOREMEDIATION AND
TRANSPIRATION OF ALFALFA
PLANTS
R.M. Hoffman1, L.C. Davis2, T.L. Marshall1, L.E.
Erickson3, R.M. Hammaker1 and W.G. Fateley1,
Departments of 1Chemistry, 2Biochemistry and
3Chemical Engineering, Kansas State University,
Manhattan, KS, 66506OPTIMIZING ADVANCED OXIDATION
PROCESSES FOR HAZARDOUS
WASTE TREATMENT
Andrew Hong1, Keith Jakob1, Mark Zappi2 and
Chiang Hai Kuo3, 1Department of Civil Engineering,
University of Utah, Salt Lake City, UT, 84112, 801 -
581-7232; 2USACE Waterways Experiment Station,
Environmental Engineering Division, Vicksburg, MS,
39180; and 3Department of Chemical Engineering,
Mississippi State University, Starkville, MS, 39705STRUCTURE-ACTIVITY
RELATIONSHIP OF HEAVY METALS
EXTRACTION FROM SOIL BY
CHELATING AGENTS
P.K.A. Hong, R.W. Okey, S.-W. Lin and T.-C. Chen,
Department of Civil Engineering, University of Utah,
Salt Lake City, UT, 84112, 801-581-7232THE EFFECTS OF METHYL-
TERTIARY-BUTYL ETHER (MTBE) ON
HEXADECANE MINERALIZATION
POTENTIALS OF NATURAL
CONSORTIA
C.M. Horan and E.J. Brown, University of Northern
Iowa, Cedar Falls, IA, 50614, 319-273-5814A STUDY OF CHUNK RUBBER FROM
RECYCLED TIRES AS A ROAD
CONSTRUCTION MATERIAL
M. Hossain1, L. Funk1, M.A. Sadeq1 and R.G. Maag2,
1Department of Civil Engineering, Kansas State
University, Manhattan, KS, 66506, 913-532-1576 and
2Bureau of Materials and Research, Kansas
Department of Transportation, 1011 North DSOB,
Topeka, KS, 66612-1568, 913-296-3711TNT SORPTION AND BOUND
RESIDUE FORMATION IN SOIL
L.S. Hundal, W.L. Powers, P.J. Shea, S.D. Comfort
and D.L. McCallister, University of Nebraska,
Lincoln, NE, 68583-0915, 402-472-6904TNT SORPTION AND BOUND
RESIDUE FORMATION IN SOIL
L.S. Hundal, W.L. Powers, P.J. Shea, S.D. Comfort
and D.L. McCallister, University of Nebraska,
Lincoln, NE, 68583-0915, 402-472-6904BIOREMEDIATION IN PREPARED-
BED BIOREACTORS: EFFECT OF
SOIL GAS OXYGEN
CONCENTRATION
C.J. Hurst, R.C. Sims, J.L. Sims, D.L. Sorensen and
J.E. McLean, Utah Water Research Laboratory, Utah
State University, Logan, UT, 84322-4110, 801-797-
2926EVALUATION OF SUBSURFACE
BIOBARRIER FORMATION AND
PERSISTENCE
G. James1, B. Warwood1, A.B. Cunningham1, J.W.
Costerton1 and R. Hiebert2, 1Center for Biofilm
Engineering, College of Engineering, Montana State
University, Bozeman, MT, 59717, 406-994 4770,
FAX 406-994 6098 and 2MSE Inc., Butte, MTRIPARIAN POPLAR TREE BUFFER
IMPACT ON AGRICULTURAL NON-
POINT SOURCE POLLUTION
J.L. Jordahl, L.A. Licht and J.L. Schnoor, Department
of Civil and Environmental Engineering, University of
Iowa, Iowa City, IA, 52242, 319-335-5178INTRINSIC BIOREMEDIATION OF
FUEL CONTAMINATION IN GROUND
WATER AT A FIELD SITE
D. Kampbell1, T. Wiedemeier2 and J. Hansen3,
1Robert S. Kerr Environmental Research Laboratory,
U.S. EPA, Ada, OK, 74820, 405-436-8564; 2Parsons
Engineering Science, Denver, CO, 80290, 303-831-
8100; and 3Air Force Center for Environmental
Excellence, Brooks AFB, TX, 78235, 210-536-4353ASSESSMENT OF FREON RELEASE
FROM POLYURETHANE FOAMS
S. Kesari, S. Kapila and G. Bertrand, Center for
Environmental Science and Technology and
Department of Chemistry, University of Missouri-
Rolla, Rolla, MO, 65401INVOLVEMENT AT SITES WITH
CULTURALLY DIVERSE
POPULATIONS
Derrick Kimbrough and Toni Lesser, United States
Environmental Protection Agency, Office of Public
Affairs (P-19J), Superfund Community Involvement
Section, 77 West Jackson Boulevard, Chicago, IL,
60604-3590, 312-886-9749 and 312-886-6685.ENVIRONMENTAL MANAGEMENT:
INDUSTRY PERSPECTIVE
Prasad S. Kodukula, Ph.D., Woodward-Clyde
Consultants, 10975 El Monte, Overland Park, KS,
66211, 913-344-1027FATE OF BENZO(A)PYRENE IN THE
RHIZOSPHERE OF FESTUCA
ARUNDINACEA
Euisang Lee1, M.K. Banks1 and A.P. Schwab2,
1Department of Civil Engineering and 2Department of
Agronomy, Kansas State University, Manhattan, KS,
66506PRACTICAL APPROACHES TO
REMEDIATING TNT-CONTAMINATED
SOIL BY FENTON OXIDATION
Z.M. Li, M. Peterson, S.D. Comfort, P.J. Shea and G.L.
Horst, University of Nebraska, Lincoln, NE, 68583-
0915, 402-472-1503BIOREMEDIATION OF NAPLS AT
TEXTUAL INTERFACES IN THE
SUBSOIL
B. Liu, W. Han, M.K. Banks and L.N. Reddi,
Department of Civil Engineering, Kansas State
University, Seaton Hall, Manhattan, KS, 66506BENCH SCALE STUDIES FOR THE
DESTRUCTIVE ADSORPTION OF
CCl4 ON CaO PARTICLES
Shubham Maheshwari1, Kenneth J. Klabunde2 and
Walter P. Walawender3, Departments of Chemistry
and Chemical Engineering, Kansas State University,
Manhattan, KS, 66506, 1913-532-4323, 2913-532-
6849 and 3913 532-5584MEASUREMENT OF TWO-PHASE
CAPILLARY PRESSURE
SATURATION RELATIONSHIP USING
THE FLEXIBLE WALL
PERMIAMETER AND FLOW PUMP
Ranjith B. Mapa and Tissa H. Illangasekare,
Department of Civil, Environmental and Architectural
Engineering, University of Colorado at Boulder,
Boulder, CO, 80309-0428, 303-492-6754MICROBIAL DEGRADATION OF TNT
BY PSEUDOMONAS SAVASTANOI
J.L. Martin, T.A. Kokjohn, S.D. Comfort and P.J.
Shea, University of Nebraska, Lincoln, NE, 68583-
0915, 402-472-1503USE OF COMPUTER
WORKSTATIONS IN THE STUDY OF
ENVIRONMENTAL GEOLOGY:
INTEGRATION OF SHALLOW
REFLECTION SEISMIC, V.S. P., AND
WELL DATA
Alex Martinez1, John F. Hopkins1, Howard R.
Feldman1, Alan J. Feltz1, Timothy R. Carr1, John H.
Doveton1, David R. Collins1, Ross A. Black2 and Neil
L. Anderson3, 1Kansas Geological Survey, Lawrence,
KS; 2University of Kansas, Lawrence, KS; and
3University of Missouri-Rolla, Rolla, MO, 65401RISKS OF RISK ASSESSMENTS
O. Mazac1, I. Landa1 and W.E. Kelly2, 1ECOLAND,
P.O. Box 512, 111 21 Prague 1, Czech Republic and
2Civil Engineering Department, University of
Nebraska, Lincoln, NE, 68588-0531, 402-472-2371NETWORK MODELING APPROACH
TO ASSESS FATE OF RESIDUAL
NAPL GANGLIA UNDER THE
INFLUENCE OF PORE FLUID
KINETICS
Sunil Menon and L.N. Reddi, Department of Civil
Engineering, Kansas State University, Manhattan,
KS, 66506, 913-532-1586, FAX 913-532-7717, E-
MAIL Reddi@ksuvm.ksu.edu and
smenon@ksu.ksu.eduBIODEGRADATION KINETICS OF
ORGANIC POLLUTANT MIXTURES
D.C. Mosteller, C.E. Larkin II and K.F. Reardon1,
Department of Chemical and Bioresource
Engineering, Colorado State University, Fort Collins,
CO, 80523-1370, 970-491-6505, E-MAIL
1reardon@lance.colostate.eduBIOREMEDIATION OF TNT WASTES
BY HIGHER PLANTS
W.F. Mueller1, G.W. Bedell1, S. Shojaee1 and Paul J.
Jackson2, 1New Mexico State University Toxicology
Program and 2Los Alamos National Laboratory, Life
Sciences DivisionMONITORING THE FATE OF 1,1,1-
TRICHLOROETHANE AND
TRICHLOROETHYLENE IN A
GROWTH CHAMBER WITH ALFALFA
PLANTS
N. Muralidharan1, R.M. Hoffman2, L.C. Davis3, L.E.
Erickson1, R.M. Hammaker2 and W.G. Fateley2,
Departments of 1Chemical Engineering, 2Chemistry
and 3Biochemistry, Kansas State University,
Manhattan, KS, 66506FROM WASTE TO RAW MATERIAL:
THE WAY OF CADMIUM AND OTHER
HEAVY METALS FROM BIOMASS TO
WOOD ASH
Michael Narodoslawksy and Ingwald Obernberger,
Institute for Chemical Engineering, University of
Technology Graz, Inffeldgasse 25, A-8010 Graz,
Austria, EuropeMODELING OF HEAVY METAL
MOVEMENT IN VEGETATED,
UNSATURATED SOILS WITH
EMPHASIS ON GEOCHEMISTRY
K.V. Nedunuri, R.S. Govindaraju and L.E. Erickson,
Kansas State University, Manhattan, KS, 66506, 913-
532-1585MODELING OF DISSOLUTION
TRANSPORT OF NON-AQUEOUS
PHASE LIQUID WASTES IN
HETEROGENEOUS AQUIFERS
S.H. Okeson1 and T.H. Illangasekare2, 1Department
of Civil Engineering, University of Colorado at
Boulder, Boulder, CO, 80309, 303-492-6754 and
2Department of Civil Engineering, University of
Colorado at Boulder, Boulder, CO, 80309, 303-492-
6644SIMULATION OF WASTE
GENERATION DURING START-UP OF
AN INTERCONNECTED PROCESS
NETWORK
B.B. Patel and L.T. Fan, Department of Chemical
Engineering, Kansas State University, Manhattan,
KS, 66506, 913-532-5584EFFECTS OF TNT AND 4-AMINO-2,6-
DINITROTOLUENE ON TALL FESCUE
GERMINATION AND EARLY
SEEDLING DEVELOPMENT
M. Peterson, G.L. Horst, P.J. Shea and S.D. Comfort,
University of Nebraska, Lincoln, NE, 68583-0724,
402-472-1143ONE-DIMENSIONAL PARTICLE
TRANSPORT MODEL IN POROUS
MEDIA
Ravandur N. Prabhushankar and Lakshmi N. Reddi,
Department of Civil Engineering, Kansas State
University, Manhattan, KS, 66506, 913-532-1586,
FAX 913-532-7717NUMERICAL CODE VALIDATION OF
MULTI-PHASE FLOW CONDITlONS
USING DATA FROM 2-D TANK
EXPERIMENTS WITH NAPLS
R. Prucha1, Tissa H. Illangasekare1 and George
Zyvoloski2, 1Civil Engineering Department, University
of Colorado, Boulder, CO, 80303, 303-492-6644 and
2Los Alamos National Laboratory, Los Alamos, NM,
505-667-1581MOBILIZATION OF NON-AQUEOUS
PHASE LIQUID WASTES IN
AQUIFERS BY HOT WATER
FLOODING
K. Pytte1 and Tissa H. Illangasekare2, 1Department of
Civil Engineering, University of Colorado at Boulder,
Boulder, CO 80309, 303-492-6754 and 2Department
of Civil Engineering, University of Colorado at
Boulder, Boulder, CO, 80309, 303-492-6644EFFECT OF PORE FLUID KINETICS
ON THE RECOVERY OF IMMISCIBLE
CONTAMINANTS FROM SOILS
L.N. Reddi and A.K. Pant, Department of Civil
Engineering, Seaton Hall, Kansas State University,
Manhattan, KS, 66506, 913-532-1586, FAX 913-532-
7717, E-MAIL Reddi@ksuvm.ksu.edu and
pant@ksu.ksu.eduTHE EFFECT OF NITROGEN
FIXATION AND FERTILIZATION IN
ALFALFA ON PHYTOREMEDIATION
OF PAHs
W.L. Rooney1, Z. Chen2, A.P. Schwab1, M.K. Banks2
and C. Wiltsie1, 1Department of Agronomy and
2Department of Civil Engineering, Kansas State
University, Manhattan, KS, 66506MODELING COLLOlD TRANSPORT IN
MACROPOROUS VADOSE ZONE
H. Ruan1 and T.H. Illangasekare2, 1Department of
Civil, Environmental and Architectural Engineering,
University of Colorado at Boulder, Boulder, CO,
80309-0428, 306-492-6754 and 2Department of
Civil, Environmental and Architectural Engineering,
University of Colorado at Boulder, Boulder, CO,
80309-0428, 306-492-6644A SIMPLE MODEL FOR
SURFACTANT-ENHANCED
REMEDIATION OF A HYDROPHOBIC
CONTAMINANT BY COMBINING THE
PUMP-AND-TREAT AND
RHIZOSPHERE TECHNOLOGIES
S.K Santharam, L.E. Erickson, L.T. Fan and P.
Gandhi, Department of Chemical Engineering,
Kansas State University, Manhattan, KS, 66506, 913-
532-5584PHYTOREMEDIATION: AN
EMERGING TECHNOLOGY FOR
CONTAMINATED SITES
J.L. Schnoor, L.A. Licht, S.C. McCutcheon, N.L. Wolfe
and L.H. Carriera, Department of Civil and
Environmental Engineering, The University of Iowa,
Iowa City, IA, 52242, 319-335-5649 and U.S.
Environmental Protection Agency, Environmental
Research Laboratory, Athens, GA, 30605, 706-546-
3301DESIGN OF BIOREACTORS FOR
AEROBIC TRICHLOROETHENE
COMETABOLISM
Robert L. Segar Jr., Department of Civil Engineering,
University of Missouri-Columbia, Columbia, MO,
65211, 314-882-0075FACTORS AFFECTING THE NATURE
OF THE METABOLITES FROM
ALACHLOR TRANSFORMATION
UNDER SIMULATED GROUND
WATER CONDITIONS
J.L. Simons, P.J. Novak, S. Christ, C. Just and G.F.
Parkin, Department of Civil and Environmental
Engineering, University of Iowa, Iowa City, IA, 52242,
319-335 5054GUIDANCE MANUAL FOR THE USE
OF PREPARED BED LAND
TREATMENT AS A BIOREMEDIAL
TECHNOLOGY
J.L. Sims, R.C. Sims and A.L. Moss, Utah Water
Research Laboratory, Utah State University, Logan,
UtT, 84322-8200, 801-797-2932ATOMIC STRUCTURE AND CRYSTAL
CHEMISTRY OF CLAYS USED IN
REMEDIATION OF HAZARDOUS
WASTE
Siva Sivalingam, TapanAm Associates, 8010 State
Line Road, KS, 66208, 913-648-5411PHOTOTRANSFORMATION OF
POLYCHLORINATED DIBENZO-P-
DIOXIN IN THE GAS PHASE AND ON
AEROSOL PARTICLES
L.D. Sivils1, S. Kapila1, Q. Yan1 and A.A. Elseewi2,
1Center for Environmental Science and Technology
and Department of Chemistry, University of Missouri-
Rolla, Rolla, MO, 65401 and 2Environmental Affairs
Division, Southern California Edison Company,
Rosemead, CA, 91770BIOTRANSFORMATION OF
POLYCHLORINATED BIPHENYLS
(PCBS) IN ST. LAWRENCE RIVER
SEDIMENTS
R.C. Sokol, C.M. Bethoney and G-Y. Rhee, School of
Public Health, State University of New York at
Albany and Wadsworth Center, NYS Department of
Health, Albany, NY, 12201-0509, E-MAIL
sokol@wadsworth.orgCOMPARING THE LEACHING
CHARACTERISTICS OF SEVEN
PESTICIDES APPLIED TO
TURFGRASS COVERED
UNDISTURBED SOIL COLUMNS
UNDER TWO IRRIGATION REGIMES
S.K. Starrett1, N.E. Christians2 and T.A. Austin3, 1Civil
Engineering Department, Kansas State University,
Manhattan, KS, 66506, 913-532-1583; 2Horticulture
Department, lowa State University, Ames, IA, 50011;
and 3Civil and Construction Engineering
Department, lowa State University, Ames, IA, 50011FATE OF ISAZOFOS,
CHLORPYRIFOS, METALAXYL AND
PENDIMETHALIN APPLIED TO
TURFGRASS COVERED
UNDISTURBED SOIL COLUMNS
S.K. Starrett, Civil Engineering Department, Kansas
State University, Manhattan, KS, 66506, 913-532-
1583FATE OF ISAZOFOS,
CHLORPYRIFOS, METALAXYL AND
PENDIMETHALIN APPLIED TO
TURFGRASS COVERED
UNDISTURBED SOIL COLUMNS
S.K. Starrett, Civil Engineering Department, Kansas
State University, Manhattan, KS, 66506, 913-532-
1583RELATIONSHIPS BETWEEN
ATRAZINE DEGRADATION, SOIL
PROPERTIES AND MICROBIAL
POPULATIONS
D.L. Tyess, P.J. Shea, S.D. Comfort and N.B. Stolpe,
University of Nebraska, Lincoln, NE, 68583-0915,
402-472-1533SYNTHESIS OF REACTION PATHS
WITH MINIMUM INVOLVEMENT OF
HAZARDOUS SUBSTANCES
J.B. Varga1, F. Friedler1,2,3, Y. Zhang3 and L.T. Fan3,
1Department of Computer Science, University of
Veszprem, H-8200 Veszprem, Hungary;
2Department of Systems Engineering, Research
Institute of Chemical Engineering, Hungary
Academy of Sciences, Veszprem, Pf. 125, H8201,
Hungary, 36-88-424-483; and 3Department of
Chemical Engineering, Kansas State University,
Manhattan, KS, 66506, 913-532-5584INACTlVATION OF METHANOGENS
RESULTING FROM THE
BIOTRANSFORMATION OF CARBON
TETRACHLORIDE AND
CHLOROFORM
L.J. Weathers and G.F. Parkin, Department of Civil
and Environmental Engineering, The University of
Iowa, Iowa City, IA, 52246, 319-335-5053TRANSFORMATION OF CARBON
TETRACHLORIDE AND
CHLOROFORM UNDER
METHANOGENIC CONDITIONS IN
THE PRESENCE OF IRON METAL
L.J. Weathers, G.F. Parkin, P.J. Novak and P.J.J.
Alvarez, Department of Civil and Environmental
Engineering, The University of Iowa, Iowa City, lA,
52246, 319-335-5053BEHAVIOR OF POLYCYCLIC
AROMATIC HYDROCARBONS (PAHs)
IN RHIZOSPHERE SOIL
S.C. Wetzel1, M.K. Banks1 and A.P. Schwab2,
1Department of Civil Engineering and 2Department of
Agronomy, Kansas State University, Manhattan, KS,
66506FUNGAL REMEDIATION OF
PENTACHLOROPHENOL
CONTAMINATED SOIL
R. Winship, M. Becerra, M. Staton and C.G. Johnston,
Mycotech Corp, 630 Utah Avenue, Butte, MT, 59701,
406-723-7770AN AUTOMATED SAMPLING SYSTEM
FOR LARGE SOIL COLUMN
TRANSPORT STUDIES
B.L. Woodbury, S.D. Comfort, M.F. Dahab and W.L.
Powers, University of Nebraska, Lincoln, NE, 68583-
0915, 402-472-1503EVALUATION OF ENHANCED
PHOTODEGRADATION FOR
DECONTAMINATION OF SOILS FROM
WOOD TREATMENT SITES
Q. Yan1, S. Kapila1, S.D. Palepu1 and A.A. Elseewi2,
1Center for Environmental Science and Technology
and Department of Chemistry, University of Missouri-
Rolla, Rolla, MO, 65401 and 2Environmental Affairs
Division, Southern California Edison Company,
Rosemead, CA, 91770BIO-WALL TECHNOLOGY:
CONCEPTUAL DESIGN AND
ANALYSIS
Xiaoqing Yang, L.T. Fan and L.E. Erickson,
Department of Chemical Engineering, Durland Hall,
Kansas State University, Manhattan, KS, 66506-
5102, 913-532-5584ROLE OF BIODEGRADATION IN THE
ATTENUATION OF ETHYLBENZOATE
IN AQUIFERS
Xiaoqing Yang, L.E. Erickson and L.T. Fan,
Department of Chemical Engineering, Durland Hall,
Kansas State University, Manhattan, KS, 66506-
5102, 913-532-5584