1 steam enhanced remediation in fractured rock (and a little about the other sites) gorm heron,...
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1
Steam Enhanced Remediation
In Fractured Rock
(and a little about the other sites)
Gorm Heron, Scientist/Engineer
Hank Sowers, CEO/Chief Operator
Dacre Bush, Geologist/Program Manager
Gregg Crisp, Site manager
SteamTech Environmental Services
Bakersfield, CA
2
Creosote DNAPL to +140 ft depth
Alluvial sands and gravels with clays
Both LNAPL and DNAPL
Approaching MCLs in 2002
Craig Eaker, SCE
160,000 gallons removed from subsurface
In-situ destruction significant
UC Berkeley – LLNL - SCE
Visalia Pole Yard
3
Alameda Point
Alameda Point (Berkeley Environmental Restoration Center)
4
Edwards AFB Site 61
5
Beale AFB
5
6
Loring: Fractured limestone
7
Florida site Full-scale clean-up with performance guarantee
Steam enhanced remediation and electrical heating
Tight pneumatic and hydraulic control
Stimulated oxidation reactions for reduction of TPH concentrations in oily areas
Detailed subsurface monitoring (temperature and electrical resistance tomography)
8
Extraction well with Hawthorn electrode
(EE)
Clay
Sand
Area A steam injection well with Hawthorn electrode (SE)
Perimeter steam injection wells (SI)
Steam
Electrode
Electrode
Deep electrode
(DE)
Well types
9
Preliminary results, Edwards AFB
Acknowledgments to:
• Stephen Watts, Edwards AFB project manager
• Dave Leeson, AFCEE
• Scott Palmer, Earth Tech project manager
• Gregg Crisp, site manager and operator
• Layi Oyelowo, Edwards AFB
Results are preliminary, conclusions have not been published or confirmed by the above persons
10
Fractured granite (quartz monzonite)
11
Objectives/questions
•Will SER be effective for removal of VOCs from fractured rock at Edwards AFB?
•How is the DNAPL mobilized and extracted?
•What are the ultimate VOC cleanup levels that can be expected at Edwards AFB using SER?
•How rapidly will the steam heat Site 61 at Edwards AFB?
•How should steam injection and extraction well-fields be designed for optimum performance at Edwards AFB?
•What is the optimal steam injection and extraction strategy for DNAPL in fractured rock at Edwards AFB?
•How long will the site stay hot after completion of the steaming?
12
Weathered zone
Fractured granite
30 ft
Hydrogeology
13
TCE distribution
14
Vertical distribution of contaminants before operations: PID readings on cores
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
0 5 10 15 20 25 30 35
Depth below grade (ft)
PID
re
ad
ing
(p
pm
)
B13 B14
15
Extraction and steam injection wells
16
Injection well
design
0
10
20
60
50
40
30
High-temperature grout (9 ft)
High-temperature grout (5 ft)
High-temperature grout (5 ft)
Coarse sand/gravel (9 ft)
Fine sand (3 ft)
#1/20 Fine sand (3 ft)
Fine sand (2 ft)
Fine sand (2 ft)
Coarse sand/gravel (13 ft)
Coarse sand/gravel (11 ft)
Wea
ther
ed z
one
(app
roxi
mat
ely
35 f
t)F
resh
bed
rock
43
34
23
12
9
52
45
65
26
31
50
#1/20 Fine sand (3 ft)
Deep injection screen (58 to 60 ft)
Middle injection screen (38 to 40 ft)
Top injection screen (18 to 20 ft)
Dep
th b
elow
gra
de (
ft)
Note: Thermocouples were attached at 5 ft intervals from 5 ft below grade to 45 ft below grade, and at 49 ft, 52 ft, 55 ft and 60 ft.
1717
1818
19
Strategy
Vacuum test: Vapor capture radius ~ 80 ft
Initially steam injection deep only, extraction shallow
Air co-injection
Extract 25 to 50 % more than injected
Monitor carefully and adjust strategy
20
VEA-5
VEA-4
VEA-3 VEA-1
VEA-2
EW-1
EW-3
EW-2
EW-4
TMA-A
TMA-D
TMA-C
TMA-B
IW-1
Subsurface monitoring network
21
ERT data planes
VEA-5
VEA-4
VEA-3 VEA-1
VEA-2
ERT data planes
22
Example ERT data plane
6/10 6/23 6/27 7/6 7/10
23
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70
Tem
per
atu
re (
OC
)
6/2
6/9
6/10
6/11
6/12
6/14
6/17
Depth below grade (ft)
Thermocouple data
24
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70
Tem
per
atu
re (
OC
)
6/2
6/9
6/10
6/11
6/12
6/14
6/17
6/20
6/21
6/22
Depth below grade (ft)
25
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70
Tem
per
atu
re (
OC
)
6/2
6/9
6/10
6/11
6/12
6/14
6/17
6/20
6/21
6/22
6/23
6/28
Depth below grade (ft)
26
Water balance
0
20,000
40,000
60,000
80,000
100,000
120,000
5/20 5/23 5/26 5/29 6/1 6/4 6/7 6/10 6/13 6/16 6/19 6/22 6/25 6/28 7/1 7/4 7/7 7/10 7/13 7/16 7/19
Tota
l v
olu
me
(g
all
on
s)
Total pumped from EW's
Total steam injected (as water)
Net extraction
27
Energy balance
0
50
100
150
200
250
300
350
400
5/20 5/23 5/26 5/29 6/1 6/4 6/7 6/10 6/13 6/16 6/19 6/22 6/25 6/28 7/1 7/4 7/7 7/10 7/13 7/16 7/19
Cum
ulat
ive
ener
gy c
onte
nt (m
illio
n B
TU)
Energy injected as steam
Energy extracted as condensate
Energy in pumped water
Energy in extacted vapors
Total energy extracted
Energy stored in formation
Energy balance
28
Vapor flow rate and PID readings
648
0
200
400
600
800
1,000
1,200
1,400
1,600
5/20 5/23 5/26 5/29 6/1 6/4 6/7 6/10 6/13 6/16 6/19 6/22 6/25 6/28 7/1 7/4 7/7 7/10 7/13 7/16 7/19
Ma
ss o
f TC
E r
em
ove
d in
va
po
r (l
bs)
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
PID
re
ad
ing
at
V-1
(p
pm
v)
lbs
ppmv
29
Headspace PID screenings on grab water samples
0
500
1,000
1,500
2,000
2,500
3,000
3,500
5/20 5/23 5/26 5/29 6/1 6/4 6/7 6/10 6/13 6/16 6/19 6/22 6/25 6/28 7/1 7/4 7/7 7/10 7/13 7/16 7/19
PID
hea
dsp
ace
read
ing
(p
pm
v)
L-1
EW-1
EW-2
EW-3
EW-4
Headspace PID data
30
Recovery of NAPL
31
Results• Successful treatability study - great data
• Steam heated site partially, and accelerated mass removal
• More than 700 lbs of VOCs removed
• NAPL recovered where no NAPL was expected
• Air injection promising for opening fractures to steam flow, and potentially for reducing risk of NAPL condensation
• ERT apparently valuable at Edwards: Heated zones showed large changes in electrical resistivity
• Very uneven steam distribution: Increased focus on temperature monitoring, also in extraction wells