Transport of Bacterial Endospores in Silica Sand Sibylle Tesar, Fulbright Scholar Dr. Barbara Williams, Faculty Dr. Robin Nimmer, Res. Supp. Sci. Angelina Cernick, Undergraduate Kristina Beaulieau, NSF REU Department of Biological and Agricultural Engineering University of Idaho
Transport of Bacterial Endospores in Silica Sand. Sibylle Tesar, Fulbright Scholar Dr. Barbara Williams, Faculty Dr. Robin Nimmer, Res. Supp. Sci. Angelina Cernick, Undergraduate Kristina Beaulieau, NSF REU. Department of Biological and Agricultural Engineering University of Idaho. - PowerPoint PPT Presentation
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Transport of Bacterial Endospores in Silica Sand
Sibylle Tesar, Fulbright ScholarDr. Barbara Williams, FacultyDr. Robin Nimmer, Res. Supp. Sci.Angelina Cernick, UndergraduateKristina Beaulieau, NSF REU
Department of Biologicaland Agricultural Engineering
University of Idaho
Outline
Research Goals – transport mechanisms / endospores
Preliminary Results Preliminary Conclusions Future Work – B. cereus, other microbes
Preliminary Research Questions
Do spores obey CFT, exhibiting more retention in higher ionic strength solution or does spore transport deviate from CFT theory as do other negatively charged particles (unfavorable attachment)?
Future: Do vegetative cells and endospores have a different charge?
Future: Do vegetative cells exhibit more attachment than endospores?
Outline
Research Goals – transport mechanisms / endospores
Preliminary Results Preliminary Conclusions Future Work – B. cereus, other microbes
Materials: Sand Properties
Saturated conductivity: Ksat = 1.8x10-4 m/sec
Dry bulk density:
b = 1.65 g/cm3
Porosity:
n = 0.34
dp/d50 .00170
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 20 40 60 80 100
Cumulative %
Par
ticl
e D
iam
eter
(m
m)
Method: Constant Head, Sand Column
Breakthrough (C/Co) of B. cereus spores as a function of ionic strength
C/Co Breakthough of B. cereus spores at different solution chemistries
-20%
0%
20%
40%
60%
80%
100%
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Dimensionless Time pore volumes
rela
tive
bre
akth
rou
gh
%
Artificial Groundwater
DDI run
start bacteria stop bacteria stop bacteria
Artificial groundwater
DDI
Column Dissection
Column Dissection
Drain column to field capacity, in the flow direction. Dissect into seven 2 cm increments STR 1: Gently place sand, allowing bridging and
loose packing, in a funnel that has been plugged with Scotchbritetm pad
STR 2: Wash off the strained bacteria by pouring the solution (the solution used in that particular experiment) over the sand into a graduated cylinder
ATT: To remove the attached bacteria, place a known amount of 2% Tweentm 80 solution into a beaker containing the sand. Stir then sonicate.
Used optical density (OD) measurements in addition to plate counting to enumerate.
(Tween and sonication proven not to affect germination efficiency)
Depth Distribution Data
"strained" bacteria in AGW run
1,E+05
1,E+06
1,E+07
1,E+08
1,E+09
1,E+10
section1
section2
section3
section4
section5
section6
section7
Bac
teri
a to
tal
in s
ecti
on
“Strained” spores in AGW run
Depth Distribution Data
"attached" bacteria in GW run
1,E+08
1,E+09
1,E+10
section1
section2
section3
section4
section5
section6
section7
Ba
cte
ria
to
tal i
n s
ec
tio
n
“Attached” spores in AGW run
Depth Distribution DataStrained and attached fractions combined
0.00E+00
2.00E+09
4.00E+09
6.00E+09
8.00E+09
1.00E+10
1.20E+10
1.40E+10
1 2 3 4 5 6 7
Strained
Attached
Outline
Research Goals – transport mechanisms / endospores
Preliminary Results Preliminary Conclusions Future Work – B. cereus, other microbes
Future Work
Compare attachment/straining of spores versus vegetative cells
Column experiments Micromodels and photographs Wet AFM
Compare zeta potential pH and more ionic strength effects Different endospore bacteria, such as S.
pasteurii, for biomineralization
Acknowledgements
Dr. Ron Crawford, Director, Environmental Biotechnology Institute, UI
Nick Benardini, PhD Candidate, MMBB Elizabeth Scherling, MS, BAE Dr. Markus Tuller, PSES David Christian, Research Support Sci.
Funding Acknowledgements
Fulbright Scholars Program USDA Hatch UI URO Seed Grant Program NSF REU program
References
Bradford, S.A., J. Šimůnek, M. Bettahar, M. vanGenuchten, and S.R. Yates. 2003. Modeling colloid attachment, straining, and exclusion in saturated porous media. Environmental Science and Technology 37: 2242-2250.
Bradford, S.A., J. Šimůnek, M. Bettahar, M.Th. vanGenuchten, and S.R. Yates. 2006a. Significance of straining in colloid deposition: evidence and implications. Water Resources Research, 42:doi:10.1029/2005WR004791.
Bradford, S.A., J. Šimůnek, and S.L. Walker. 2006b. Transport and straining of E. coli 0157:H7 in saturated porous media. Water Resources Research (in review).
Li, X., TD. Scheibe, and W.P. Johnson. 2004. Apparent decreases in colloid deposition rate coefficient with distance of transport under unfavorable deposition conditions: a general phenomenon. Environ. Sci. Technol., 38: 5616-5625.
Redman, J.A., S.L. Walker, and M. Elimelech. 2004. Bacterial adhesion and transport in porous media: Role of the secondary energy minimum, Environ. Sci. Technol., 38:1777-1785.
Tufenkji, N., J.A. Redman, and M. Elimelech. 2003. Interpreting deposition patterns of microbial particles in laboratory-scale column experiments, Environ. Sci. Technol., 37: 616-623.
Tufenkji, N., Elimelech, M. 2005. Breakdown of colloid filtration theory: Role of the secondary energy minimum and surface charge heterogeneities. Langmuir 21: 841-852.