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Page Contents
- Introduction
- Granular iron research
- Direct measurement of groundwater velocity
- In situ denitrification
- Research Highlights
- Projects at a glance
Research Group
Welcome and thank you for your interest in my research the program in the Geology Department at KU. See the summaries below for information about the various research projects underway and planned by my group. Relevant papers produced from the research are cited and full reference information is given on my Publications page. |
Granular Iron Research
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The work began with investigations into the effects of sorption, competition, aging and and assessment of
the role of Fe2+ on the reduction of organic compounds by granular iron (Devlin et al., 1998).
An evaluation of Fe0 as an electron donor for denitrification followed (Devlin et al., 2000).
To preserve the iron surface from abrasion during batch tests, the GEM reactor was developed, in which the iron
is held stationary by a magnet while the solution is stirred (Devlin and Allin, 2005). This apparatus was
used to show that common anions in groundwater, at concentrations within the typical range, exert a notable effect
on iron reactivity (Devlin and Allin, 2005). Carbonate was paradoxically reported to be a reactivity enhancer
and a reactivity depressant in various studies by others. The GEM reactor was used to show that the complex behavior was
due in part to shifting stabilities of iron oxides and carbonates, depending on the carbonate solution concentration
(Bi et al., 2009). The limitations of mass transport on contaminant reduction rates was investigated
in sand-granular iron mixtures. It was found in experiments with both chlorinated solvents, and the much
faster reacting nitroaromatics, that more than 25% by weight sand caused notable declines in contaminant transformation
rates (Bi et al., 2009). The preceding work was based primarily on a simple conceptual model of reactions on the iron surface, i.e., that the surface can be treated as an homogeneous one with sorption occurring only to reactive sites. The development of a Kinetic Iron Model (KIM) provided a means of divorcing the contributions of sorption from those of reaction in contaminant disappearance rates (Devlin, 2009). The KIM permitted quantification of the isotherm parameters describing sorption to reactive sites as distinct from non-reacting sites, which could be evaluated from retarded transport (Bi et al., 2010). Work is underway examining the changes to these parameters as iron ages, to develop numerical models that incorporate these processes explicitely, and that compare parameter values across different classes of organic compounds. Work is also underway to link microscale changes to the iron surface to changes observed in the KIM parameters. |
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Direct Measurement of Groundwater Velocity
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The Point Velocity Probe (PVP) research began with prototypes designed by Devlin, and constructed by undergraduates
at the University of Waterloo (Steve DiBiasi, Nora Donald). This led to more detailed testing by Labaky et al. (2007),
who demonstrated the technology in the laboratory and with numerical models. Field comparisons of the PVP against other
velocity estimation methods were reported by Labaky et al. (2009).
The first application of PVPs was for investigating the effects of biostimulation on flow in a gasoline plume (Schillig et al. 2011). For this project, PVPs were stacked in multilevel arrays to provide a detailed picture of groundwater velocity on a transect across the ambiant flow direction (Devlin et al., 2009, see image at right). This work also linked bioactivity to measureable ground penetrating radar response, raising the possibility that radar could be used to infer zones of altered flow in in situ treatment zones (Schillig et al., 2010). Subsequently, PVPs were used to map the velocity field around a recirculating well in an effort to define the flow experimentally and explain tracer behavior (Devlin et al., in revision). Ongoing work is underway to simplify the assembly of PVPs using a a 3D model of the device and a prototype printer. PVPs are also being used to localize the onset of microbial growth in an heterogeneous aquifer by examining local flow changes in a denitrification treatment zone that differ from background changes. Further plans are underway to use PVPs to document flow in stream banks in the USA and the South Pacific, and in regional flow studies of flow through thin, continuous beds in western Canada. |
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In situ denitrification
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Nitrate is the most common groundwater contaminant in the world. It is introduced to groundwater mainly through
agricultural activity, and is widespread as a result. Removal of nitrate from groundwater is difficult to do at a
reasonable cost. Removal in situ is a promising alternative. This research began with an assessment of
stimulating in situ denitrification in an aquifer near the town of Baden, Ontario. A carbon source in the
form of acetate was shown to be a highly effective electron donor for denitrification throughout the aquifer (Devlin
et al., 2000). A pilot test ensued in which acetate was injected across the ambient flow direction in
weekly pulses that were allowed mix by dispersion as the acetate was transported toward a pumping municipal well.
A detailed assessment of the heterogeneity of the site was made prior to a pilot scale remediation test (Gierczak
et al., 2006). The system achieved complete nitrate removal within the test zone, with no noticeable
iron or sulfate reduction, and no nitrite production (Gierczak et al., 2007).
The success of the Baden experiments led to the work continuing at the municipal wells located outside Woodstock, Ontario, in collaboration with Dr. David Rudolph at the University of Waterloo and Oxford County, Ontario. The heterogeneity at the Woodstock site was found to be more pronounced than what had been observed at Baden, based on PVP velocity measurements and a natural gradient tracer test (Critchley et al., in preparation). Groundwater velocities at the site were observed to be as high as 30 m/day. Nonetheless, laboratory testing of core material has shown that denitrifying bacteria are present throughout the aquifer. A pilot scale cross-injection test, similar to the Baden experiment, indicated acetate could stimulate denitrification at the site, but additional work is needed to optimize the process in the highest velocity layers. |
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Research Highlights
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Prototype PVPs. The first printed plastic PVPs came off the prototype printer early in 2011. KevinWalter produced the first units using Google Sketchup and the hardware in Dr. Dan Hirmas' lab in the Geography Dept. The first designs were aimed at measuring horizontal flow only, and the PVPs were intended to be dedicated as single probes per borehole. Kevin has since gone on to design a multilevel version of the probes, and the most recent prototypes will have the ability to measure vertical and horizontal flow. |
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GPR response to microbial growth in porous media. Undergraduate Elisheva Patterson, and graduate student Peter Schillig, shown at right, were awarded the top two places for their research presentations in the G-Hawker Symposium, held at the University of Kansas in October, 2007. The presentations dealt with complimentary studies in the field (Schillig) and laboratory (Patterson) demonstrating a relationship between ground penetrating radar (GPR) wave velocities and microbial activity in biostimulated sand. This research has application in the bioremediation industry and in the monitoring of natural attenuation of pollutant plumes. |
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Effect of microbial activity on flow. With the rise of permeable reactive barriers for groundwater remediation, questions need to be asked concerning how long they last and what controls their performance. It is frequently noted that rates of pollutant transformation in laboratory tests do not match rates observed in the field. In this work it is hypothesized that residence time in the reactive zone of an aquifer undergoing bioremediation is affected by the microbial activity there. Peter Schillig performed his Masters research on this topic for which he was awarded best student paper at the AGU Joint Assembly, Acapulco, Mexico, in May, 2007. Peter was also awarded the prestigious Self Fellowship to continue his research at the doctoral level at KU. In 2009 he was awarded a GSA grant to conduct laboratory column tests aimed at linking aquifer texture to microbial hot spots. At right Peter poses beside the grill of a Dept. SUV containing feathers from a turkey vulture he bagged in flight. |
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Sorption vs. reaction on granular iron. Observed reaction rates of organics with granular iron depends on both the quantity sorbed and the surface reaction rate. Similar rates might be observed for the two distinct cases in which either sorption is large but surface reactions are low, or sorption is low but surface reaction rates are high. Unfortunately, uniquely calculating the sorption and reaction parameters necessary to model such scenarios is difficult for reacting species. The literature reports only one extraction based method to accomplish this separation of processes. However, a new method, involving combined column and batch tests, was tested by Melissa Marietta with promising results (undergraduate thesis work) for three nitroaromatic compounds. The work won her the AEG student paper award, 2005. At right Melissa presents her work to the AEG membership after winning the award. |
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In situ sequential treatment. Over the past few years, field trials were carried out to test the viability of sequencing in situ technologies for groundwater remediation. The first such test was conducted at the Alameda Naval Air Station (pictured at right), where granular iron and a biosparge unit were coupled to remove a mixture of chlorinated solvents and petroleum hydrocarbons from the groundwater The test facility performed very well, removing over 99% of the cis-dichloroethene that was initially present in the water (> 200 mg/L in some locations) and all detectable hydrocarbons (max. BTEX = 10 mg/L). This work was published in 2000 in the Journal of Contaminant Hydrology with Morkin, Barker and Butler. See Publications for the complete citation. |
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Sequenced in situ treatment was also tested in a controlled field experiment at the CFB Borden site. In that test, two biodegradation systems were constructed in series to treat a plume containing carbon tetrachloride, chloroform, tetrachloroethene and toluene. The first treatment was anaerobic biodegradation stimulated by benzoate and nutrient additions made from a nutrient injection wall (NIW). The second treatment was aerobic biodegradation from a residual oxygen barrier (ROB). The two treatment units were constructed in a 24 m long sheet pile alleyway. Pictured at right is the enclosure built to protect the experiment. Removal rates exceeding 99% were experienced for all primary compounds except toluene. Also, low but detectable amounts of cis-dichloroethene were close to breakthrough a the end of the experiment. Both these problems could be alleviated with diminished benzoate additions at the NIW, thus reducing oxygen demand at the ROB. This work was coauthored with Katic and Barker, and was published in the Journal of Contaminant Hydrology in 2004. |
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Selected Projects at a Glance
| Research Topic | Graduate Student
Undergraduate (U) or Collaborators (C) |
Status | Completion |
| TBA | Brian Gibson | M.S. in progress | Fall 2013 |
| Measuring groundwater velocity in coarse-grained deposits | Kevin Walters | M.S. in progress | Fall 2012 |
| Diffusion in heterogeneous porous media | Angela Eichler | M.S. in progress | Fall, 2012 |
| Scale dependent processes affecting granular iron reactivity | Rubina Firdous | Ph.D. Research in progress | Ph.D. Fall 2012 |
| M.S.: Microbial Activity and its Effects on
Groundwater Velocity in a Contaminated Aquifer
Ph.D. Localizing microbial growth in heterogeneous aquifers (tentative) |
Peter Schillig | M.S. Research complete
Ph.D. research in progress Best Student Paper at AGU Joint Assembly, May, 2007 First place presentation at the G-Hawker Symposium, University of Kansas Dept. of Geology, Oct., 2007 Awarded honors for M.Sc. work Awarded Self Fellowship for Ph.D. studies 1)Schillig, P., Devlin, J.F., McGlashan, M., Tsoflias, G., Roberts, J.A. 2011. Transient heterogeneity in an aquifer undergoing bioremediation of hydrocarbons. Ground Water, v. 49, no. 2, 184-196. 2) Schillig, P.C., Tsoflias, G.P., Roberts, J.A., Patterson, E.M., Devlin, J.F. 2010. Ground-penetrating radar observations of enhanced biological activity in a sandbox reactor, Journal of Geophysical Research, v. 115, G00G10, doi:10.1029/2009JG001151. |
M.S. Feb. 2008
Ph.D. Fall 2011 |
| Diffusion of solutes in heterogeneous porous media | James Lyons | M.S. project in progress | M.S. Fall 2012 |
| Effect of mixed anions
(HCO3- - SO42-, ClO4-
- SO42-) on Fe0 reactivity |
Hillary Kelly (U) | B.S. Research in progress with IMSD support:
Kelly, H.S., Devlin, J.F. 2011. Effect of mixed anions (HCO3- - SO42-, ClO4- - SO42-) on Fe0 reactivity. Presented at the University of Kansas-Haskell Indian Nations University Undergraduate Research Symposium, Haskell University, Lawrence, KS, April 26. |
B.S. Spring 2012 |
| B.S.: Assessment of three mixing methods for
studying reaction kinetics with granular iron
M.S.: Mapping a nitrate plume at a fertilizer manufacturing plant |
Natalie Garven (Burris) | B.S. thesis complete, manuscript published as:
Garven, N.L., Devlin, J.F. 2006. Minimizing Mass Transfer Effects in Granular Iron Batch Tests Using GEM Reactors. J. Envir. Eng. 132, 1673. M.S. Research in progress |
B.S. Spring 2005
M.S. Fall 2010 |
| Separating the kinetic and sorption parameters of mixed chlorinated solvents in contact with granular iron | Huang Bei | Ph.D. Research complete
Thesis awarded honors Bi, E., Devlin, J.F., Huang, B., Firdous, R. 2010. Transport and kinetic studies to characterize reactive and non-reactive sites on granular iron. Environmental Science and Technology, v. 44, no. 14, 5564–5569. Additional articles in progress |
Spring, 2011 |
| B.S.: Investigation of the effects of anion mixtures
on the reactivity of granular iron
M.S.: Characterization of a Dipole Flow System Using Point Velocity Probes |
Ian Bowen | B.S. Complete: Bi, E., Bowen, I., Devlin, J.F. 2009. Effect of Mixed Anions (HCO3--SO42- - ClO4-) on Fe0 Reactivity. Environmental Science and Technology v. 43, no. 15, 5975-5981. M.S. Complete: papers pending |
B.S. Spring 2008
M.S. Fall 2010 |
| Accuracy and angular range of mini-PVPs for groundwater velocity measurement in 3D | Alek McElroy (U) | Research Assistant, Spring, 2010 | Spring 2010 |
| 1)Optimizing iron/sand mixtures for TCE removal from water
2) Investigating effects of mixed anions on Fe0 reactivity 3) Use of the KIM to characterize reactive and non-reactive sites on granular iron 4) A novel interactive teaching tool for graduate studies |
Erping Bi (C) | Post doctoral Research complete
1) Bi, E., Devlin, J.F., Huang, B., Firdous, R. (in press). Transport and kinetic studies to characterize reactive and non-reactive sites on granular iron. Submitted to Environmental Science and Technology. 2) Bi, E., Bowen, I., Devlin, J.F. 2009. Effect of Mixed Anions (HCO3- - SO42- - ClO4-) on Fe0 Reactivity. Environmental Science and Technology v. 43, no. 15, 5975-5981. 3) Bi, E., Devlin, J.F., Huang, B. 2009. Effects of mixing granular iron with sand on the kinetics of trichloroethylene reduction. Ground Water Monitoring and Remediation, v. 29, no. 2, 56-62. |
Fall 2008 |
| Assessment of GPR response to microbial growth | Elisheva Patterson (U) | B.S. Complete
Second place presentation at the G-Hawker Symposium, University of Kansas Dept. of Geology, Oct., 2007 Schillig, P.C., Tsoflias, G.P., Roberts, J.A., Patterson, E.M., Devlin, J.F. (in press) Ground penetrating radar observations of enhanced biological activity in a sandbox reactor. Submitted to the Journal of Geophysical Research Letters. |
Spring 2009 |
| Detailed assessment of groundwater velocities on the surface of a point velocity probe | Neil Kinnebrew (U) | Research Assistant, Fall 2006 | Spring 2007 |
| Estimating groundwater velocity with a point velocity probe | Shawn Showman (U) | Research Assistant, Summer 2006 | Summer 2006 |
| Using grid distortion to simulate the effects of heterogeneity on modeled plumes | Kathy Baker | M.S. Project complete | Mar. 2008 |
| Permeability versus Surface Reactivity on the Longevity of Granular Iron Reactive Barriers | Michelle Dambacher | M.S. thesis complete, manuscripts in progress
Thesis awarded honors |
Fall 2005 |
| Separating sorption and kinetic paramaters using a new kinetic model for the nitroaromatic compounds 4ClNB, 4AcNB and 4MeNB reacting with granular iron | Melissa Marietta (U) | B.S. thesis complete
Winner of the 2005 AEG student paper competition Manuscript published as: Marietta, M.L., Devlin, J.F. 2005. Bringing Groundwater Quality Research to the Watershed Scale (Proceedings of GQ2004, the 4th International Groundwater Quality Conference, held at Waterloo, Canada, July 2004). IAHS Publ. 297, 2005. |
Spring 2005 |
| Development of a Point Groundwater Velocity Probe | Walid Labaky | Ph.D. research complete
Nominated for the Pearson Award Manuscript published as: 1) Labaky, W., Devlin, J.F., Gillham, R.W. 2007. A probe for measuring groundwater velocity at the centimetre scale. Environmental Science and Technology, v. 41, no. 24, 8453-8458. 2) Labaky, W., Devlin, J.F., Gillham, R.W. 2009. Field comparison of the point velocity probe with other groundwater velocity measurement methods, Water Resour. Res., 45, W00D30, doi:10.1029/2008WR007066. |
Sept., 2004 |
| Assessing Granular Iron Reactivity | Jessica Leuty (U) | Undergraduate summer research 2003 | 2003 |
| Effect of Iron Dilution (with non-reactive material) in Reactive Barriers | Janet Patchen (U) | Undergraduate summer research 2003:
Devlin, J.F., Patchen, J. 2004. The effect of diluting granular iron with a non-reactive porous medium on contaminant transformation rates. Presented at the 5th Joint Conference of the IAH-CNC and the Canadian Geotechnical Society (CGS), Quebec City, October 24-27. |
2003 |
| In situ denitrification of an aquifer near a municipal water supply well | Richard Gierczak | M.S. research complete
Nominated for the Dean of Science Award Manuscripts published as: 1) Gierczak, R., Devlin, J.F., Rudolph, D. 2006. Combined Use of Laboratory and In situ Hydraulic Testing to Predict Preferred Flow Paths of Solutions Injected Into an Aquifer. Journal of Contaminant Hydrology, v. 82, 75-98. 2) Gierczak, R., Devlin, J.F., Rudolph, D. 2007. Field test of a nutrient injection wall for stimulating in situ denitrification near a municipal water supply well. Journal of Contaminant Hydrology v. 89, 48–70. |
Aug., 2002 |
| Saturation kinetics of organics reacting with granular iron | Christine March | M.S. research complete, manuscript published as:
Devlin, J.F. March, C. 2003. Investigating the kinetic limitations of granular iron over a large range of 4-chloronitrobenzene concentrations. Presented at the 225th American Chemical Society Meeting, New Orleans, LA, March 23. |
Feb., 2002 |
| Sorption of Anilines to Master Builder's Iron | Mike Smith | M.S. Research complete, manuscript in progress.
Nominated for the Dean of Science Award |
Feb. 2001 |
| Effect of geochemical composition of water on granular iron reactivity | Kevin Allin | M.S. thesis complete
Manuscript published as: Devlin, J.F., Allin, K.O. 2005. The effects of major anions on the reactivity of granular iron using a glass encased magnet (GEM) batch reactor. Environmental Science and Technology, v. 39, no. 6, 1868-1874. |
Jun., 2000 |
| Treatment of mixed contaminant plumes with in situ sequential treatment | Denis Katic, Mary Morken, Jim Barker (C) | M.S. research complete
Manuscript published as: 1) Devlin, J.F., D. Katic, McMaster, M., Barker, J.F. 2002. Evaluating natural attenuation in a controlled field experiment by mass balances, flux fences and snapshots: a comparison of results. Groundwater Quality Natural and Enhanced Restoration of Groundwater Pollution, S.F. Thornton and S. Oswald eds., IAHS Publication no. 275. 2) Devlin, J.F., Katic, D., Barker, J.F. 2004. In situ sequenced bioremediation of mixed contaminants in groundwater. Journal of Contaminant Hydrology, v. 69, no. 3-4, 233-261. 3) Morkin, M., Devlin, J.F., Barker, J.F., Butler, B.J. 2000. In situ sequential treatment of a mixed contaminant plume. Journal of Contaminant Hydrology, v. 45, 283-302. |
2001 |