Spelling suggestions: "subject:"groundwater purification"" "subject:"groundwater urification""
1 |
Experimental design of physical aquifer models for evaluation of groundwater remediation strategiesHumphrey, Mark D. 21 July 1992 (has links)
Groundwater resources have become seriously threatened
due to improper use by industrial, municipal, and even public
sectors. Widespread contamination of aquifer systems has
jeopardized human health and the environment and methods for
restoring these systems are needed. Biological and chemical
in situ remediation, where contaminants are degraded within
the natural system, has become the foremost technique for
cleaning up affected sites. However, before in situ
remediation can be implemented, studies of the sites'
physical, chemical, and biological characteristics must be
done.
Physical aquifer models (PAM's) were constructed for use
in evaluating groundwater remediation strategies in porous
media. The PAM's offer a unique approach for work of this
kind, the most important of which are opportunity for
conducting large-scale transport experiments under controlled
conditions, and maintaining geometric, dynamic, and reactive
similitude. The PAM's consist of aluminum reactors, 4.00 m
(length) x 2.00 m (width) x 0.20 m (height), supported by a
steel framework. Reservoirs at each end of the reactor
permit adjustment of hydraulic gradient across its length.
An array of 40 fully-penetrating wells allows versatility in
sampling, injection, or extraction of solutes. Experiments
can be performed under confined or unconfined, steady-state
or transient conditions where temperature, pressure, and
hydraulic gradient can be controlled.
Plumbing design, well design, sampling protocol, and
media-packing procedure were developed and tested in dye and
bromide tracer experiments. The results of dye experiments
in a water-filled PAM demonstrated the effectiveness of the
inlet and outlet port design and construction of the wells.
This was evident through control of a symmetrical plume that
developed within a uniform flow field. Protocols for
sampling, injection, and extraction using the well array were
also effective based on observed dye plume development and
bromide concentration contour plots. A new approach for
packing sand was used to create a statistically equivalent
homogeneous and isotropic porous media. Results of bromide
tracer experiments indicate that this condition of
homogeneity and isotropy was achieved.
The PAM's worked well for creating the desired
experimental conditions needed for studying transport of
solutes (non-reactive in this case) in porous media.
Additional experimental work will be done to develop and
expand more of their capabilities (e.g. transient flow,
confined conditions, heterogeneic media) for which they were
designed. Remediation strategies will be investigated using
the developed PAM's and it is hoped that results obtained
from these studies will be successfully applied to field
situations. / Graduation date: 1993
|
2 |
Kinetic modeling of heterogeneous chemical reactions with applications to the reduction of environmental contaminants on iron metalBandstra, Joel Zachary 05 1900 (has links) (PDF)
Ph.D. / Environmental Science and Engineering / In the past decade, permeable reactive barriers containing zero-valent iron metal (FePRBs) have emerged as the most significant new technology for the treatment of groundwaters contaminated with chlorinated organic compounds and, more recently, other organic contaminants such as 2,4,6-trinitrotoluene (TNT). Principle issues relating to the design, implementation, and monitoring of FePRBs include the rates of contaminant transformation, the resulting distribution of products, and the potential changes in FePRB performance due to aging of the iron material. Each of these issues is, at its root, a problem of chemical kinetics. In this thesis, commonly observed kinetic expressions for contaminant transformation are derived. Analyses of the simplifications involved in these derivations indicate that the forms of the rate laws are correct (either exactly or approximately) over a wider range of conditions than previously expected and that reaction rates may respond in unexpected fashion to changes in concentrations of reacting species or iron loading. These theoretical developments are applied to experimental investigations of product distribution and FePRB longevity for the treatment of TNT contaminated groundwaters.
|
3 |
Effect of 2,4,6-trinitrotoluene (TNT) on carbon fixation rates in elodea nutalliBenton, Mona Kathryn 05 1900 (has links)
No description available.
|
4 |
Alginate Encapsulated Nanoparticle-Microorganism System for Trichloroethylene RemediationShanbhogue, Sai Sharanya January 2012 (has links)
Nanoscale zero-valent iron (NZVI) particles were encapsulated in calcium alginate capsules for application in environmental remediation. TCE degradation rates for encapsulated and bare NZVI were similar indicating no adverse effects of encapsulation on degradation kinetics. Microorganisms were separately encapsulated and used along with encapsulated NZVI and co-encapsulated in calcium alginate capsules. Batch experiments were performed to test the efficacy of the combined iron-Pseudomonas sp. (PpF1) system. The combined system removed 100% TCE over the first three hours of the experiment followed by 70% TCE removal post TCE re-dosing. Complete reduction of TCE was achieved by NZVI between 0-3 h and the second phase of treatment (3-36 h) was mostly achieved by microorganisms. Experiments conducted with co-encapsulated NZVI-D.BAV1 achieved 100% TCE removal. During the first three hours of the experiment 100% TCE removal was achieved by NZVI, and 100% removal was achieved post re-dosing where D.BAV1 accomplished the treatment. / Department of Civil Engineering, North Dakota State University
|
5 |
Adsorption of MS-2 bacteriophage to silicaStocking, Kristin, 1959- January 1989 (has links)
Batch and column experiments were performed to investigate the adsorption of bacteriophage MS-2 to silica at pH 5. Linear isotherm analysis of batch experiment data gave partition coefficient (KP) estimates of 270 cm³/g and 580 cm³/g for 4°C and 24°C, respectively. Breakthrough-type column experiments indicated that sorption and desorption were slow, as evidenced by a slow approach to breakthrough and tailing of the desorption limb. A non-equilibrium advection-dispersion model with all adsorption sites on the silica assumed to be kinetically controlled was used to model the column data. The model-generated parameters yielded Kp estimates 1000-fold smaller than those given by isotherm analysis and indicated that the time scale for desorption is on the order of 1-6 hours.
|
6 |
Innovative soil mix technology constructed permeable reactive barrier for groundwater remediationAbunada, Ziyad January 2015 (has links)
No description available.
|
7 |
Effect of particle size and natural organic matter on the transport and fate of latex nanoparticles in saturated porous mediaPelley, Andrew John. January 2007 (has links)
No description available.
|
8 |
Demonstration of a permeable barrier technology for the in-situ bioremediation of pentachlorophenol contaminated groundwaterCole, Jason David 05 May 2000 (has links)
A pilot scale demonstration of a biological permeable barrier was conducted in a pentachlorophenol-contaminated aquifer at a wood preserving facility. A permeable reactor was constructed to fit within a
large diameter well. Arranged in series, a cylindrical reactor 24" x 36" (0.61 x 0.91m) (diameter x height)
was partitioned to provide three biological treatment zones. Pentachlorophenol (PCP) biodegradation was
evaluated under several environmental conditions using a mixed microbial consortium supported on
ceramic saddles. Imitation vanilla flavoring (IVF), a mixture of propylene glycol, guaiacol, ethyl vanillin
and sodium benzoate, served as the electron donor. In the absence of exogenous substrate, PCP was not
degraded in the inoculated permeable barrier. Substrate addition under oxidizing conditions also failed to
initiate PCP removal. Anaerobic conditions however, promoted in-situ PCP degradation. PCP reductive
dechlorination resulted in the transient production of 3,4,5-trichlorophenol through sequential ortho
dechlorinations. Continued carbon reduction at the meta and para positions resulted in 3,4-dichlorophenol
and 3,5-dichlorophenol production. Complete removal of all intermediate degradation products was
observed. Reactor operation was characterized through two independent laboratory and field companion
studies. Experiments were conducted to evaluate (1) the effect of supplemental electron donor
concentration (IVF) and (2) the effect of sulfate, a competitive electron acceptor on PCP reductive
dechlorination. Results from laboratory and field conditions were consistent. (1) In the presence of an
exogenous electron donor, PCP degradation was independent of supplemental donor concentration (10, 25,
50, 100 mg COD/L). However, a comparatively slower rate of PCP degradation was observed in the
absence of electron donor. (2) The presence of sulfate was not inhibitory to PCP degradation. However,
compared to systems evaluated in the absence of sulfate, slower rates of PCP transformation were
observed. Passive operation and low energy requirements, coupled with potential contaminant
mineralization suggest that the biological permeable barrier is a highly effective tool for subsurface
restoration. / Graduation date: 2000
|
9 |
Mass transfer constraints on the feasability on in situ bioremediation of contaminated groundwaterFry, Virginia A., 1959- 24 June 1994 (has links)
Graduation date: 1995
|
10 |
Fe°-enhanced bioremediation for the treatment of perchlorate in groundwaterJose Sanchez, Aiza Fernanda, 1972- 07 July 2011 (has links)
Not available / text
|
Page generated in 0.0958 seconds