HR: 1340h
AN: H33D-1628    [Abstracts]
TI: Effect of Pore-scale Velocity on the Biodegradation of Contaminants during Transport in Porous Media
AU: * Mendoza-Sanchez, I
EM: itzam@msu.edu
AF: Instituto Politecnico Nacional, Escuela Superior de Ingenieria y Arquitectura, Mexico City, 07738, Mexico
AU: * Mendoza-Sanchez, I
EM: itzam@msu.edu
AF: Michigan State University, Department of Civil and Environmental Engineering, A121 Engineering Research Complex, East Lansing, MI 48824, United States
AU: Autenrieth, R L
EM: r-autenrieth@tamu.edu
AF: Texas A&M University, Department of Civil Engineering, 3136 TAMU, College Station, TX 77843-3136, United States
AU: McDonald, T J
EM: tmcdonald@srph.tamhsc.edu
AF: Texas A&M University, Department of Environmental and Occupational Health, SRPH Bldg., Room 112, College Station, TX 77843-1266, United States
AU: Cunningham, J A
EM: cunning@eng.usf.edu
AF: University of South Florida, Department of Civil and Environmental Engineering, 4202 E Fowler Ave, ENB 118, Tampa, FL 33620, United States
AB: Column experiments were conducted to evaluate the effect of pore velocity on the extent of biodegradation of cis- dichloroethene (cis-DCE) during transport in porous media. The columns were filled with homogeneous glass beads and inoculated with the KB-1 culture (provided by SiREM, Guelph, Ontario, Canada), which is capable of complete dechlorination of perchloroethene to ethene. The columns were fed continuously with a synthetic groundwater containing a constant concentration of cis-DCE. Three different pore flow velocities (0.03, 0.08, and 0.51 m/day) were tested in duplicate, subjecting each column to a constant velocity for the entire experiment. Dechlorination of cis-DCE to vinyl chloride and ethene was monitored over time and space within the columns. Protein concentrations, also measured over time and space, were used to relate cell growth to biodegradation efficiency. At the end of the experiment, microbial DNA was harvested from the columns, and denaturing gradient gel electrophoresis (DGGE) was used to determine differences in the microbial communities that had developed in the columns subjected to different flow rates. The results show that the pore velocity has a strong influence on the microbial population and the degree of dechlorination. At high flow velocity (0.51 m/day), the degradation of cis-DCE to ethene was complete, and the organism capable of cis-DCE dechlorination ({Dehalococcoides sp.}) was present at the end of the experiment. In contrast, at medium and low flow velocities (0.08 and 0.03 m/day), incomplete dechlorination was observed with an absence or low concentration of {Dehalococcoides sp}. These results suggest that it is important for field-scale groundwater remediation to understand the interaction between physical and biological processes on the scale of single pores.
DE: 0418 Bioremediation
DE: 1800 HYDROLOGY
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2007 Fall Meeting