R. Guy Riefler's Research Group
Department of Civil Engineering
Ohio University

Purpose:

I seek to investigate chemical and biological interactions that affect the transport and transformation of pollutants in the environment. My research currently focuses on remediation of explosives contamination and restoration of lands impacted by coal mining. In my work, I frequently employ analytical chemistry, molecular biology, and numerical models.

Current Research Projects:
Jeremy Krohn (MS expected March 2006) is investigating the biofouling of a wetland system designed to treat acid mine drainage. A series of vertical flow wetlands and aerobic wetlands receiving highly acidic underground mine leachate with high iron and aluminum concentrations has filled with viscous black sludge. Tracer tests have shown significant short-circuiting and a significant decline in treatment efficiency. Through detailed sampling and mass balance analysis, the locations of significant limestone dissolution, sulfur reducing bacteria activity, and metal deposition have been identified. Based on Jeremy's biological and chemical analysis, a remedy for the treatment system is being proposed. A journal article manuscript is also being prepared.

sponsored by Ohio Department of Natural Resources

 Regan Welch (MS expected June 2006) is investigating the use of iron nanoparticles for remediation of TNT and perchlorate contaminated aquifers. Particles have been synthesized and characterized by size distribution and iron content. Through batch kinetic assays, Regan is determining the kinetics of reduction reactions with the contaminants. Transport of the particles and pollutants will be assessed in a column study.

sponsored by United States Geological Survey through Ohio State University
Sushma Guruswamy (MS expected June 2006) is investigating the use of native grasses to detoxify soil contaminated with propellants. US Army firing ranges and training facilities are routinely contaminated with low levels of propellants like 2,4-dinitrotoluene, nitroglycerine, and perchlorate, due to incomplete combustion. The US Army seeks remediation and stabilization alternatives that do not intrude on training operations. Phytoremediation with native grasses could accomplish that objective. In this study, Sushma is growing three native grasses hydroponically and in contaminated soil, to measure uptake and transformation of the contaminants.

sponsored by Army Corps of Engineers

 John Krinks (MS expected June 2007) is investigating the microbial community established in constructed wetlands treating acid mine drainage. Manganese contaminated seeps are increasingly treated by Pyroluscite systems in which a limestone bed is inoculated with proprietary iron and manganese oxidizing bacteria. The systems have been effective over the short term, but it is not clear how long the inoculated bacteria community persists in the limestone bed. Using selective media, tRFLP (terminal restriction fragment length polymorphism), and clone libraries, John is determining the microbial community at various locations in the limestone bed.

proposal under review by Ohio Department of Natural Resources
In the 1950s parts of Southeastern Ohio were strip-mined resulting in severe erosion. Little Leading Creek in Rutland, Ohio continues to be inundated with sand even though the mine in the watershed have been reclaimed. The sand deposition has resulted in heavy flooding in the area and has greatly impacted the habitat for fish in the creek. In this study, we are determining sediment transport rates through the watershed to determine zones for erosion and aggradation, characterizing the sediment to estimate sediment origin, developing a GIS, HEC Ras model, and a sediment transport model for the watershed, and proposing possible remedies to reduce flooding and improve fish habitat. This project, directed by Dr. Riefler, is being tackled with two co-PIs, three graduate students, and two undergraduate researchers.

sponsored by Ohio Department of Natural Resources and Leading Creek Watershed Group

Grants:

  1. Assessment of Uptake and Transformation of the Propellants, 2,4-Dinitrotoluene, Nitroglycerine, and Perchlorate, in Grasses, Army Corps of Engineers, 4/1/05 - 12/31/05, $25,000.
  2. Little Leading Creek Sediment Study, ODNR and Meigs Soil and Water Conservation District, 4/1/05 - 3/31/07, $116,000.
  3. Transport and Fate of Iron Nanoparticles in Groundwater, US Geological Survey, 4/1/05 - 2/28/06, $53,232.
  4. Studies to Support of Rhizodegradation of RDX and Propellants in Range Soils, U.S. Army Faculty Research and Engineering Program, 6/1/04 - 3/31/05, $14,500.
  5. Identification of Sludge Forming Bacteria in a Treatment Wetland, Stocker Undergraduate Intern Program, 9/1/04 - 3/31/05, $2,900.
  6. Assessment of the Simmons Run AMD Treatment Wetland, Ohio Department of Natural Resources, 1/1/04-7/1/05, $65,000.
  7. Analysis of the role of plants and bacteria in TNT contaminated soil to improve phytoremediation strategies. Ohio University Student Enhancement Award. 5/8/03-5/8/04, $3,994.
  8. Phytoremediation (microbial stimulation) of distributed source contaminants from soils using native grasses, Ohio University Challenge Grant, 5/13/03-5/13/04, $6,000.
  9. Humification of 2,4,6-trinitrotoluene by nitroreductase activity in the rhizosphere, Ohio University Challenge Grant, 11/19/02-11/19/03, $2,400.
  10. Ion chromatograph for environmental program, Ohio University Stocker Endowment, 2/15/2002, $30,375.
  11. The environmental relationship to bacterial transformation kinetics is governed by intracellular cofactors, Ohio University Challenge Grant, 7/24/01-7/24/02, $6,000.
  12. Internal redox potential controls TNT biotransformation rates, Ohio University Research Council, 11/15/00-11/15/01, $6,500.

Peer Reviewed Publications:

  1. Riefler, R. G. and V. Medina. submitted. Fate of RDX and TNT in decaying plant material. Chemosphere.
  2. Riefler, R. G. and V. Medina. in press. Phytotreatment of propellant contamination. Chemosphere.
  3. King, S., McCord, B, and Riefler, R. 2005. Capillary electrophoresis single-strand conformation polymorphism analysis for monitoring soil bacteria. J Microbiol Meth. 60(1):83-92.
  4. Riefler, R. G., and B. F. Smets. 2003. Comparison of a type curve and a least squared errors method to estimate biofilm kinetic parameters. Water Res. 37(13):3279-3285.
  5. Riefler, R. G., and B. F. Smets. 2002. NAD(P)H:FMN oxidoreductase inactivation during 2,4,6-trinitrotoluene reduction. Appl. Environ. Microbiol. 68(4):1690-1696.
  6. Riefler, R. G. and Smets, B. F. 2000. Enzymatic reduction of 2,4,6-trinitrotoluene and related nitroarenes: Kinetics linked to one-electron redox potentials. Env. Sci. Technol. 34(18):3900-3906.
  7. Smets, B. F., Riefler, R. G., Lendenmann, U. and Spain, J. C. 1999. Kinetic analysis of dinitrotoluene biodegradation in an aerobic fluidized bed biofilm reactor. Biotechnol. Bioeng. 63(6):642-653.
  8. Riefler, R. G., Ahlfeld, D. P. and Smets, B. F. 1998. Respirometric assay for biofilm kinetics estimation: Parameter identifiability and retrievability. Biotechnol. Bioeng. 57(1):35-45.
  9. Ahlfeld, D. P., Zafirakou, A. and Riefler, R. G. 1998. Solution of the groundwater transport management problem by sequential relaxation. Adv. Water Resour. 21(7):591-604.
  10. Riefler, R. G. and Ahlfeld, D. P. 1996. The impact of numerical precision on the solution of confined and unconfined optimal hydraulic control problems. Haz. Waste Haz. Mat 13(2):167-176.

Other Publications:

  1. Riefler, G, Krohn, J., and Stuart, B. 2005. Recomendations for redevelopment of a vertical flow wetland system impacted by biofouling. ARC Symposium. December 14-15, 2005. Athens, OH.
  2. Riefler, G, Chang, T., Stuart, B., Kleski, J., Fang, Y., and Arthur, B. 2005. Sediment transport in the Little Leading Creek watershed. ARC Symposium. December 14-15, 2005. Athens, OH.
  3. Riefler, G, Chang, T., Stuart, B., Kleski, J., Fang, Y., and Arthur, B. 2005. Sediment transport in the Little Leading Creek watershed. ORBCRE Symposium. October24-25, 2005. Dayton, OH.
  4. Riefler, R.G. and V. Medina. 2005. Grass phytoremediation: Explosives uptake and fate in decomposing plant tissue. 21st Annual International Conference on Sediment and Contaminated Soils. October 15-20, 2005. Amherst, MA.
  5. Medina, V., Larson, S., Weathersby, A., Morrow, A., Jones, M., and Riefler, R. 2005. Laboratory studies of the feasibility and optimization of perchlorate biodegradation. Eight International In Situ and On-Site Bioremediation Symposium. June 6-9, 2005. Balimore, MD.
  6. Riefler, G, Krohn, J., Romerser, R., and Stuart, B. 2004. Impact of sedimentation on the performance of a system of constructed wetlands treating acid mine drainage. ARC Symposium. December 8-9, 2004. Athens, OH.
  7. Krohn, J., Romerser, R., Riefler, G, and Stuart, B. 2004. Impact of sedimentation on the performance of a system of constructed wetlands treating acid mine drainage. ORBCRE Symposium. August 18-20, 2004. Athens, OH.
  8. Stephanie King, Bruce McCord, and R. Guy Riefler. 2004. Plant/bacteria relationship in remediation of 2,4,6-trinitrotoluene contaminated soil. Remediation of Chlorinated and Recalcitrant Compounds Conference sponsored by Battelle. Monterey, CA. May 2004.
  9. Stephanie King and R. Guy Riefler. 2004. SSCP Analysis of a Bacterial Community by Capillary Electrophoresis for Remediation of TNT-Contaminated Soil. Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy (PITTCON). Chicago, IL. March 8-11, 2004.
  10. Riefler, R., King, S., and McCord, B. 2003. Bioaugmentation of TNT contaminated soil using plants. Partners in Environmental Technology Technical Symposium & Workshop sponsored by SERDP and ESTCP. December 2-4, 2003. Washington, DC.
  11. King, S. and Riefler, R. G. 2003. Remediation of 2,4,6-trinitrotoluene contaminated soil using a plant/bacterial combination. 225th American Chemical Society National Meeting. March 23-27, 2003. New Orleans, Louisiana.
  12. Riefler, R. G. and Smets, B. F. 2001. Kinetics of NAD(P)H:FMN oxidoreductase reduction of 2,4,6-trinitrotoluene. Gordon Research Conference. July 22-27, 2001. New London, Connecticut.
  13. Smets, B. F., K. Chandran, and R. G. Riefler. 2001. Biodegradation of Invididual Organic Contaminants. In S. E. Powers (ed.), AEESP Environmental Engineering Processes Laboratory Manual.
  14. Smets, B. F., K. Chandran, and R. G. Riefler. 2001. Estimation of Biokinetic Parameters. In S. E. Powers (ed.), AEESP Environmental Engineering Processes Laboratory Manual.
  15. Riefler, R. G. and Smets, B. F. 2000. Kinetics of NAD(P)H:FMN oxidoreductase reduction of 2,4,6-trinitrotoluene. Northeast Industrial and Hazardous Waste Conference, Renselear Polytechnique Institute, Troy, New York.
  16. Smets, B. F. and Riefler, R. G. 1999. Comparison of a visual-based and least-squared-based method to estimate biofilm kinetic parameters. IAWQ Specialized Conference on Biofilm Systems. October 17-20, 1999. New York, New York.
  17. Riefler, R. G. and Smets, B. F. 1999. Kinetic studies linking enzymatic reduction of trinitrotoluene and metabolites with one-electron reduction potentials. Biodegradation of Nitroaromatic Compounds and Explosives, Second International Symposium. September 8-9, 1999. Leesburg, Virginia.
  18. Riefler, R. G. and Smets, B. F. 1999. Modeling the mineralization of trinitrotoluene and dinitrotoluenes in aerobic/anaerobic biofilm. Battelle In Situ and On-Site Bioremediation, Fifth International Symposium. April 19-22, 1999. San Diego, California.
  19. Ahlfeld, D. P., Riefler, R. G. and Mulligan, A. E. 1998. A new code for MODFLOW-coupled groundwater management of unconfined aquifers. MODFLOW'98 International Conference. Golden, Colorado.
  20. Ahlfeld, D. P. and Riefler, R. G. 1998. Documentation for MODOFC: A Program for Solving Optimal Flow Control Problems Based on MODFLOW96 Simulation. Version 2.0.
  21. Ahlfeld, D. P. and Riefler, R. G. 1996. The impact of numerical precision on optimal groundwater hydraulic control. ASCE North American Water and Environment Congress. Anaheim, California.

Laboratory Facilities:

I have primary responsibility for developing and maintaining the environmental laboratories. Much of the equipment used by students in the labs is relatively new and our capabilities have greatly explanded over the past five years. Major equipment my research group has purchased and maintains includes:

Reviews:

Courses Taught:

last update: October 1, 2005