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Why we need upscaling to describe microbiological processes in groundwater: Examples from fractured porous media and bioaugmentation technologies
P.J. Binning
Two problems where upscaling is needed
Bioaugmentation
Enhanced biodegradation in clays
Pesticide contamination of groundwater
GEUS, 2006, 2009
% W
ater
sup
ply
wel
ls w
ith p
estic
ides
Non detect
0 %
100 %
“the technique for improvement of the capacity of a contaminated matrix (...) to remove pollution by the introduction of specific competent strains or consortia of microorganisms”(El Fantroussi and Agathos, Curr. Opin. Microbiol. 2005)
liquid microbial culture immobilized
microbes
activated soil microbes with mobile genes rhizosphere
biaogumentation
Boldt et al. 2004
phyto-augmentation
Shimidzu et al. 2002
Bioaugmentation
Immobilized microbes
Time (day)
0 5 10 15 20 25 30
Sim
azin
e (m
g kg
-1)
020406080
100120
• simazine, agricultural soil• 50% water saturation• 2-mm alginate beads• Pseudomonas sp. MHP41
Morgante et al. (2010) FEMS Microbiol. Ecol. 71:114-126
Data
Model
Linuron
Herbicide used since 1965, now banned in 7 of 27 EU countries
Suspected developmental or reproductive toxin
First-order mineralization rate
Time (h)
0 96 192 288 384 480
14C
O2 (
% o
f ini
tial 14
C)
0
20
40
60
80
100
( )ktCC −= exp0
k=0.216 day-1
Reaction time scales about 5 days
Variovorax sp. SRS16
Diffusive transport
0)()(=+∇+•∇−
∂+∂
wwwaHwwaHw kCCK
tCK θθθθθ
aw DD
Expected diffusive time scales17 days for 20mm bead separation
Mineralization time scale
Bead spacing (mm)
5 10 15 20 25 30
Tim
e (d
ay)
102
103
104
105
106
100%35%10%
90% removal, 2mm beads
1 year
20 years
saturation
, ,w b b w s sb s eff
b s b s
m V m Vdm k k k mdt V V V V
θ θ= − − = −
+ +
, ,w b b b w s s seff
b s
k V k Vk
V Vθ θ+
=+
( )tkmm eff−= exp0
A simple mixing model
sV
bVFor Vb/(Vs+Vb)=1% reaction rate reduced by a factor of 100
Bead spacing (mm)
0 20 40 60 80 100
k eff
(day
-1)
10-7
10-6
10-5
10-4
10-3
10-2
10-1
100
t 90%
(day
)
100
101
102
103
104
105
106
Simple mixing model
Degradation rate in beads
Degradation rate for soil
effk 90t
2mm beads, 100% saturation
Application of technologyRequire ~24 tons 2mm beads for 1 ha to remove 90% linuron in 100 days
(spaced at <10 mm in a layer of 100 mm)
ww
w.g
eogr
aph.
org.
uk/p
hoto
/393
25
Effect of water infiltration
0)()(=+
∂∂
+∇+•∇−∂
+∂ww
wwwaHw
waHw kCz
CqCKt
CK θθθθθaw DD
Effect of water infiltration
Bead spacing (mm)
5 10 15 20 25 30
C/C
0
0,0
0,2
0,4
0,6
0,8
1,0
100%35% 10%
column 18.5 cm
Reduction in outlet concentration
100%35% 10%
Saturation
Increasing column length, decreasing
bead density
mineralization rate predicted by the model(% of benzoate mineralized per day)
0.0 0.5 1.0 1.5 2.0 2.5 3.0
expe
rimen
tal m
iner
aliz
atio
n ra
te(%
of b
enzo
ate
min
eral
ized
per
day
)
0
10
20
30
40
50
60
70
7%27%68%
Effect of cell dispersal
Dechesne et al. (2010) Env. Sci. Technol. 44:2386-2392
full colonization=bugs everywhere
minor colonization=bugs in beads
Conclusions
Bioaugmentation has poorer performance in field than expected from lab results
Models developed to predict field performance• Simple Mixing Models: Can upscaling help here?• Process models
Soil moisture, infiltration and other environmental conditions affect performance
Cell dispersal may potentially improve the technology (observed in sand, but limited in soil)
Sand aquiferChalk aquifer
Clayey till
DTU og Orbicon
Enhanced biodegradation in clays
•Long term secondary source of contamination!
•Remediation of chlorinated solvents?
•Stimulated Reductive Dechlorination, SRD?
Geological characterizationGeostatistical toolsHydrogeological model
Modeling ofSRD in clay till
Optimization of enhancementSpreading of reagentsInjection methods
Remediation designPractical tools
Microbial and chemical process understanding
Biogeochemical site characterization
What do clays look like?
Christiansen et al. (2008). ES&T, 42, 570–576.
Fracture mapping
Sand lenses
Fracture distribution – Field data
SprækkeJAGG, 2008Klint, 2001, PhD Thesis
Cumulative fracture spacing (average distance between vertical/sub-vertical fractures)
Dep
th m
belo
w g
rou
nd
su
rface
(m
)Silstrup
Haslev 1
Gedser
Flakkebjerg
Avedøre
Havdrup
Fårdrup
Lillebæk
Ranzausgade
Slæggerup
Ringe
Haslev 2
Kamstrup
Estrup
Mammen
Grundfør
Højstrup 2HøjstrupGjorslev
TuneSigerslev 1
Sigerslev 2
Vasby
Location0 0,5 1 1,5 2 2,5 3 m
0
0.5
11.5
2
2.5
3
3.5
44.5
5
5.5
6
6.5
77.5
8
8.5
1
2
3
1
2
3
Anaerobic dechlorination
Only Dehalococcoides
species
Various microorganisms
Model system - simplification
Model developed in Comsol Multiphysics
ERD injection of donor and bacteria
fractures
Injection depths
Contaminant mass in matrixSum of chlorinated ethenes: TCE, DCE and VC
Mass in matrix
Full scale application of enhanced reductive dechlorination in clayey till (Sortebrovej, Denmark)
Anaerobic dechlorination associated with sandstringers in clayey till
14,2
14,3
14,4
14,5
14,6
14,7
0 1 2 3 4 5 6 7 8Chlorinated ethenes [mg/kg]
Dep
th [m
bgs
.]
TCE cis-DCE VC Ethen
Clay core
Modeling - scenarios
Injection of donor in high permeability conduitsSpecific degraders only related to sandstringers or fracturesReaction zones surrrounding sandstringers
Base line – no dechlorinationRZ10 – 10 cm reaction zoneRZ30 – 30 cm reaction zoneRZ60 – 60 cm reaction zoneBest case – entire matrix1 m
Generation of degradationproducts – treatment area
RZ305 year after start of remediation
Before remediation
Comparison with field data
Degree of dechlorination 2 years after remediation
Mass of contaminants in treatment area
Start of remediation at day 0
Case study challenges:
How do we model geology?
How do we model hydraulics, including injection of substrate?
Where are the bugs?
How do we model the biogeochemistry?
AcknowledgementsPart 1M. Owsianiak, A. Dechesne, B.F. SmetsMikołaj Owsianiak, Arnaud Dechesne, Philip J. Binning, Julie C. Chambon, Sebastian R. Sørensen, Barth F. Smets, Evaluation of Bioaugmentation with Entrapped Degrading Cells as a Soil Remediation Technology, Environmental Science and Technology, 44, 19, 7622-7626, doi: 10.1021/es101160u, 2010.
Part 2Julie Chambon, Gabriel Manoli, Philip Binning, Ida Damgaard, Mette Broholm, Camilla Christiansen, Gitte Lemming, Poul L. BjergJulie C. Chambon, Mette M. Broholm, Philip J. Binning and Poul L. Bjerg, Modeling multi-component transport and enhanced anaerobic dechlorination processes in a single fracture – clay matrix system, Journal of Contaminant Hydrology,112, 1-4, 77-90, 2010.