Pamela Schultz Birak, University
of North Carolina at Chapel Hill, Chapel Hill, NC
abstract
Kayleigh Dunnett, University of
Illinois at Urbana Champaign,
Urbana, IL
abstract
Laura Nicklaus, Bradley University,
Peoria, IL
abstract
Pamela Schultz
Birak
Rheological Characteristics of
Manufactured Gas Plant Tars and Implications for
Remediation
Pamela Schultz
Birak, University of North Carolina at Chapel Hill, 148
Rosenau Hall CB 7431, Chapel Hill, NC 27599-7431,
U.S.A., Tel: (919) 966-6332, Fax: (919) 966-7911,
pamela_birak@unc.edu
Scott
C. Hauswirth, University of North Carolina at Chapel
Hill, 148 Rosenau Hall CB 7431, Chapel Hill, NC
27599-7431, U.S.A., Tel: (919) 966-6332, Fax: (919)
966-7911, shauswirth@unc.edu;
Cass T. Miller, University of North Carolina at Chapel
Hill, 148 Rosenau Hall CB 7431, Chapel Hill, NC
27599-7431, U.S.A., Tel: (919) 966-1024, Fax: (919)
966-7911, casey_miller@unc.edu
Thousands of former manufactured
gas plants (MGPs) are located across the U.S.
At these sites, one of the
most significant sources of contamination is by-product
tar.
The viscosity of MGP tars
can vary several orders of magnitude and plays an
important role in affecting the migration and
distribution of these dense non-aqueous phase liquids in
the subsurface.
Understanding the flow or
rheological behavior of a particular tar is critical for
designing effective pumping strategies and for
understanding potential further migration of subsurface
tar plumes.
In this work, we conducted a
rheological analysis of tars recovered from two former
MGPs, as well as a recently produced coal tar.
Viscosity
was measured using a rotational viscometer, where both
temperature and shear rate can be controlled.
Data from the rotational
viscometer were fit to standard functions to allow for
the prediction of viscosity for various temperatures and
shear rates.
At low shear rates and
temperatures relevant to subsurface systems, tars were
found to be non-Newtonian such that the viscosity was no
longer constant and increased with decreasing shear
rate.
Thus, the movement of a
creeping tar plume could be over- predicted by relying
on viscosity measurements in the Newtonian range.
Viscosity was also found to
be very sensitive to temperature and decreased by orders
of magnitude from 5 to 80 degrees C.
This decreased viscosity
could be useful for thermal approaches to remediation
when the mobilization of trapped residual is a desired
effect.
Kayleigh Dunnett
Biodegradation of Tert-butyl Alcohol
(TBA) using Biological Granular Activated Carbon
(Bio-GAC)
Kayleigh
Dunnett, University
of Illinois at Urbana Champaign, 4162 Newmark Civil
Engineering Laboratory, 205 N. Mathews Ave, Urbana
IL 61801- 2352, Tel: 217-333-8121, Email:
dunnett2@illinois.edu
Dr. Kevin T. Finneran, University of Illinois at
Urbana Champaign, 3221 Newmark Civil Engineering
Laboratory, 205 N. Mathews Ave, Urbana IL 61801-
2352, Tel: 217-244-7956, Email:
finneran@illinois.edu
Tert-butyl
alcohol (TBA), a metabolite of the gasoline additive
methyl tert-butyl ether (MTBE), is a common
groundwater contaminant encountered at petroleum
remediation sites.
This work explored the
capability of YZ2, a novel pure culture, to
completely degrade TBA aerobically in both batch
studies and in continuous-flow columns containing
biologically activated granular carbon (bio-GAC),
simulating an ex-situ remedial system.
YZ2 mineralized TBA from
0.5mM to 50mM, which is significantly higher than
previously reported cultures.
The level at which TBA
limited the cellular activity was 45mM; however,
mineralization still proceeded up to 50mM.
YZ2
growth and corresponding TBA oxidation rates within
saturated activated carbon were compared with rates
quantified in pure aqueous media; results
demonstrate that GAC decreases oxidation kinetics
for TBA.
Batch studies quantified
the kinetics of abiotic TBA sorption to activated
carbon versus biological TBA oxidation using bio-GAC
to compare the rates and efficiencies of physical
removal processes to biological strategies.
Data demonstrate that adsorption may be more
efficient at high TBA concentration, and that
previously reported KOC
values for TBA
were underestimates.
In addition, pH levels
increased to as high as 10.2 once activated carbon
was added to solutions containing TBA, which
inhibited microbial growth.
The
continuous-flow bio-GAC columns mimicked a field
bio-GAC unit and focused on different potential
inoculation strategies and the long-term
capabilities of YZ2 to degrade TBA as a continuous
culture.
Current
data indicate lower effluent TBA concentrations
within the bio-GAC column for 70 days, compared to a
sterile GAC control column.
However, the overall
stoichiometry of the mineralization pathway
indicates that dissolved oxygen concentrations in
influent water may limit TBA degradation in the
bio-GAC column, preventing complete degradation.
We are using these data
to develop a strategy for biological regeneration of
GAC, which may be the most effective use of
inoculated, TBA degrading cultures.
Laura Nicklaus
Magnesium Corrosion and Stabilization/Solidification
Effectiveness Using the Toxicity Characteristic Leaching
Procedure
Laura Nicklaus
(Student), Department of Civil Engineering and
Construction, Bradley University, 1501 W. Main, Peoria,
IL 61625, USA, Tel: 309-677-2778, Fax: 309-677-2867
Mariana
Caffaro(Student), Department of Civil Engineering and
Construction, Bradley University, 1501 W. Main, Peoria,
IL 61625, USA, Tel: 309-677-2778, Fax: 309-677-2867
Robert W. Fuessle, PhD, Department of Civil Engineering
and Construction, Bradley University, 1501 W. Main,
Peoria, IL 61625, USA, Tel: 309-677-2778, Fax:
309-677-2867, Email: fues@bradley.edu
Max. A. Taylor, PhD, Department of Chemistry and
Biochemistry, Bradley University, 1501 W. Main, Peoria,
IL 61625, USA, Tel: 309-677-3026, Fax: 309-677-3023,
Email:
mtaylor@bradley.edu
Stabilization/Solidification (S/S)
is designated by EPA as the “Best Demonstrated Available
Technology” for 68 waste codes described by the Resource
Conservation and Recovery Act, and it is the second
most-used technology at Superfund sites.
Binders for S/S are
frequently proprietary, but they often include Portland
cement and pozzolans such as fly ash.
The advantages of using fly
ash are twofold: a reduction in cost of materials as the
waste fly ash partially replaces cement, and an
improvement in the microstructure of the binder as the
pozzolan reacts with calcium hydroxide to create
additional calcium silicate hydrate (CSH).
CSH represents about 65% by
volume of normal completely-hydrated cements.
CSH is largely responsible
for concrete strength and impermeability. These
potential improvements are offset by deleterious
elements frequently found in hazardous wastes.
Past research in S/S has
focused on regulated metals and their effects on cement
microstructure.
However, less dangerous
metals such as magnesium frequently found in hazardous
wastes have not received the same level of scrutiny.
In recent years, research in
cement has investigated the mechanisms of magnesium
corrosion; magnesium reacting with CSH and destroying
its durability.
Relatively high levels of
magnesium may be found in certain cements, or it may
penetrate cements from seawater or soils.
Magnesium is especially
harmful in conjunction with sulfate, another common
industrial waste component.
Recent research indicates
that magnesium corrosion may be less harmful for cements
without pozzolans.
This research investigates
how magnesium and fly ash addition impacts S/S treatment
effectiveness after short and long-term curing.
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