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Session B
Remediation – of Soil
and Groundwater
Part I
Chair: Marja Tuomela
Ph.D., Co-op Bionautical and University of Helsinki, Finland
Environmental forensics. Searching for a major unknown PCE source
in an industrial area using different tools, Birkerød, Denmark
Thomas Hauerberg Larsen
M.Sc., Ph.D., Orbicon, Denmark
Development of an iron-based soil mixing remediation method
for energyefficient treatment of chlorinated solvents
Per Lindh
Ph.D., Swedish Geotechnical Institut, Sweden
Da Nang – an outstanding thermal remedy 5 years later
Niels Ploug
Sales and Product Manager, Krüger, Denmark
Danang
An out standing thermal remedy
five years later
Nordrocs 2018
Use of Agent Orange in Danang
Krüger Soil Remediation
• Operation Ranch Hand – herbicides for
defoliation
• Agent Orange contained dioxin as
2,3,7,8-TCDD
• Over 100,000 barrels used in Danang
• USAID lead agency for cleanup
Danang Airbase - 1972
Impacted areas
Krüger Soil Remediation
o Environmental assessment – 151 samples
o Excavation areas
o ~20 Ha total area
o 15 cm til > 3 m depth
o 80.000 – 90.000 m3
Choice of technology
Krüger Soil Remediation
Efficiency Only known alternativ to reach Vietnamese dioxin standards (1,000 ppt)/(150 ppt)
Environmental impact IPTD scores lowest impact in EA
Economy IPTD costs in same range as other alternatives when long term landfill O&M was considered
Why IPTD?
Krüger Soil Remediation
Design
Krüger Soil Remediation
Design
Krüger Soil Remediation
Pile
Structure
Grade Level
Insulated
Sidewall Panel
Steel Sheeting
Drain Piped
to Sump
Drainage
Layer
Insulated
Floor
Insulated Surface
Cover
Air Inlet Well Heater-Only
Well
Horizontal Vapor
Extraction Well
• 105 m x 70 m x 6 m pile
• Volume = 43.750 m3
• 1,254 heater wells
• Horizontal extraction
• Air inlet
• 56 temperature-monitering wells
• Treatment of gas & fluid by cooling,
phase separation, filtering and adsorption
Krüger Soil Remediation
Phase 1 - operation
Krüger Soil Remediation
Phase 1: October 2014 continuous rain
Krüger Soil Remediation
Temperature avg.
by treatment zone
depth
Phase 1 – Soil temperatures
Krüger Soil Remediation
Confirmatory sampling
Krüger Soil Remediation
• Verify concentrations < 150 ppt
• Pile divide into 1 m decision units
• Triplicate collected for one layer
-1 m
-0 m
-2 m
-3 m
-4 m
DU-1
DU-2
DU-3
DU-4
Phase 1 Final Sample Reults May 2015
Krüger Soil Remediation
Cooling and Removing Treated Material
Krüger Soil Remediation
o Phase 1 pile quenched May-July 2015
o Treated soil removed Sep/Oct 2015
Design modifications for Phase 2
Krüger Soil Remediation
Phase 2 – Design Modifications
Krüger Soil Remediation
Design
o Heater elements
o Cover
o Liquid Treatment Plant
o Mass balance
o Collect initial samples in pile
o Increase sampling on Liquid
Treatment Plant
Modified Heater Design
Krüger Soil Remediation
Bottom 2m boost
Re design vapor cover
Krüger Soil Remediation
210 kg/cm2
210 kg/cm2
Phase 2 - Operation
Krüger Soil Remediation
Phase 2 – Pre-tretament concentrations
Krüger Soil Remediation
Phase 2 – Soil temperatures
Krüger Soil Remediation
50100150200250300350400450500550600650700750800850900950100010501100
104070
100130160190220250280310340370400430460490520550580610
10/07/16 11/26/16 01/15/17 03/06/17 04/25/17 06/14/17 08/03/17
Tem
pe
ratu
re [º
F]
Tem
pe
ratu
re [º
C]
Date
50 cm 150 cm 250cm 350 cm 450 cm 550 cm 600 cm
Start heatin
g
Qu
ench
start
10
0ºC
Heaters o
ff &start
of
con
firmatio
nsam
plin
gTemperature avg.
by treatment zone
depth
Phase 2 – Final Sample Results (June 2017)
Krüger Soil Remediation
IPTD met stringent cleanup standard with > 99,99%
Robust design necessary
Pre design to complete
cleanup in less than 9 years
Danang Airport ready for
transfer in 2018
Conclusions
Krüger Soil Remediation
Project team
Krüger Soil Remediation
1
Development of an iron-based soil mixing
remediation method for energy
efficient treatment of chlorinated solvents
Per Lindh, PhD
2
Clarification
In geotechnical engineering stabilization with a binder is to blend
a soil with a binder to enhance the geotechnical performance
of the soil.
In remediation this technique is called solidification.
3
Background
A former remediation project with TCE contaminated soil
run by Region Hovedstaden has shown good results
regarding degradation of the pollution. However, it resulted in
low strength and bearing capacity of the treated soil.
This problem was caused by the method used,
blending a slurry mix of bentonite and ZVI in the soil.
4
Goal
Our goal is to find an energy efficient, robust soil mixing
method to reduce the pollutant and stabilize/solidify any
remaining pollution.
The treatment should also give a stable ground for future
development of the treated area.
5
Spiked soil or in situ polluted soil?
During the first discussion regarding spiked or in situ polluted
soil we chose spiked soil due to;
• Less spread in pollution level – better control
• We could design the experiment in a better way
• Less handling of pollutants in the lab
6
Challenges
This project involves new testing methods that need to
be developed including handling of the specimens due
to the volatile compounds. How do we produce a specimen
were we are sure to measure degradation not evaporation?
Optimizing testing program with respect to quality,
reproducibility and budget
Choosing a good iron oxide source together with different
binders – iron sulfate adversely affect strength development.
Finding a strength increase that is both practical and slow
enough to let the iron oxide decompose the pollution.
7
Nondestructive testing - method
8
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 5 10 15 20 25 30 35 40 45 50
P-w
ave
ve
loci
ty (
m/s
)
Curing time (days)
1_5050_55_0_1
1_5050_55_0_2
1_5050_0_6000_1
1_5050_0_6000_2
2_5050_XX_0_1
2_5050_XX_0_2
3_5050_XX_0_1
3_5050_XX_0_2
5%_5050_0_0_2
5%_5050_0_0_5
Nondestructive testing - results
9
Specimen one, blend one for strength testing
Specimen two, blend one for degradation testing (day x)
Recipe one blend one
Blending mould
Specimen three, blend one for degradation testing (day x + 30)
Specimen four, blend one for degradation testing (day x + 90)
Specimen one, blend two for strength testing
Specimen two, blend two for degradation testing (day x)
Recipe one blend two
Blending mould
Specimen three, blend two for degradation testing (day x + 30)
Specimen four, blend two for degradation testing (day x + 90)
How do we reduce laboratory work and keep quality
10
Specimen one, blend one for strength testing
Specimen two, blend one for degradation testing (day x)
Recipe one blend one
Blending mould
Specimen three, blend one for degradation testing (day x + 30)
Specimen four, blend one for degradation testing (day x + 90)
Specimen one, blend two for strength testing
Specimen two, blend two for degradation testing (day x)
Recipe one blend two
Blending mould
Specimen three, blend two for degradation testing (day x + 30)
Specimen four, blend two for degradation testing (day x + 90)
How do we reduce laboratory work and keep quality
If necessary additional specimens
11
Mixing parameters
Binder component one
0.0 0.2 0.4 0.6 0.8 1.0
Bin
de
r co
mp
on
en
t tw
o
0.0
0.2
0.4
0.6
0.8
1.0
Y = 1 - X
0.0
0.2
0.4
0.6
0.8
1.0
0.00.2
0.40.6
0.8
1.0
0.20.4
0.60.8
1.0
Z =
Bin
der
com
ponent th
ree
X = Binder component oneY = Binder component two
(1,0,0)
(0,0,1)
(0,1,0)
Z =
1 - X
X =
1 - Z
Y = 1 - X
x+y+z=1
12
Bin
der
conte
nt
TC
E le
vel
Fe(II) content
23-Factor design
33-Factor design
Low
Low
Low
Medium
Medium
Medium
High
High
High
Process parameters
13
Bin
der
conte
nt
TC
E le
vel
Fe(II) content
33-Faktorförsök
FC CCD
Low
Medium
High
Low
LowMedium
Medium
High
High
Process parameters
14
Bin
der
conte
nt
TC
E le
vel
Fe(II) content
33-Faktorförsök
Box-Behnken design
Low
Medium
High
Low
LowMedium
Medium
High
High
Process parameters
15
Different goals – How to choose?
• Degradation
• Strength
• Resistance
• Economy
• Environmental aspects
16
Simplex lattice
How to choose the optimum blend?
S lag0 10 20 30 40 50 60 70 80 90 100
P ersu lfa te
0
10
20
30
40
50
60
70
80
90
100
C em ent
0
10
20
30
40
50
60
70
80
90
100
> 3 5 0 0
< 3 5 0 0
< 3 0 0 0
< 2 5 0 0
< 2 0 0 0
< 1 5 0 0
< 1 0 0 0
< 5 0 0
< 0
Fi tte d S u rfa ce ; V a ri a b l e : UCS
DV : UCS ; R-sq r= .9 9 0 9 ; A d j :.9 8 8 5
M o d e l : Q u a d ra ti c (so m e te rm s we re re m o ve d fro m fu l l m o d e l )
Example from PAH contaminated sediment
17
How to choose the optimum level?
18
Shear strength as a function of P-wave velocity
P-wave velocity (m/s)
200 400 600 800
Sh
ea
r str
en
gth
(kP
a)
0
100
200
300
400
500
600
in situ sampled specimens tested in labregression from in situ sampleHW LB 14 day specimens from this study
pl-2017
Can we use same parameters in lab and in situ?
19
I would like to thank you for your attention and also thank
my colleagues in this project
Katerina Hantzi, Region Hovedstaden
Anna Toft, Region Hovedstaden
Annika Fjordbøgge, DTU
Cecilia Toomväli, SGI
Annika Åberg, former at SGI (Sweco)
Erik Bergstedt, SGU
Wilhelm Rankka, SGI
Torben Højbjerg Jørgensen, COWI
Fredrik Burman, SGI
Christopher Robb, Geosyntec
Control group
Helen Kennedy, SGI
Klas Arnerdal, SGU
Carsten Bagge Jensen, Region Hovedstaden
Contact information: [email protected]
Once upon a time…or the mystery of the
hidden PCE source Thomas Hauerberg Larsen, Orbicon
Ida Damgaard, Capital Region of Denmark
(CRD)
Anna Toft, CRD
Katerina Hantzi, CRD
Arne Rokkjær, CRD
Flemming Vormbak, CRD
Kresten Andersen, Orbicon
Simon Hansen, Orbicon
Outline
• Once upon a time….
• The set-out – triggering of the quest for a PCE source
• Finding the source (or almost we believe…..)
– Analysis of the remedial stream
– Model with particle tracking
– Comparing known source with remedial stream (CSIA)
– A new set of wells, and another new set of wells….
• Whats next?
• Wrap up
Once upon a time in 1961 (my year of
birth) and now
Primary developement of Birkerød Industrial Area (BIA) took place in the 1960’ies – some newer buildings too. Total area around 50 ha.
Activities/sources in the area
Small – medium sized companies
12. september
2018
4
Chrome plating
TCE storage and handling for degreasing metal & electronics
Broken sewers
Production of glues, detergents etc.
Repair shops & garages
Known & probable polluted sites in BIA
TCE
TCE TCE
TCE
TCE
PCE Cr6
TCE
Red hatch: Known pollution (V2 register) Blue hatch: Suspected pollution (V1 register) Yellow arrow: Overall groundwater flow direction appr 10 m/y Bold characters are known major sources
TCE
General conceptual model chlorinated
spills in BIA
12. september
2018
6
Sandy clay-till
Meltwater sand
Unsaturated sand
Remedies
12. september
2018
7
TCE Thermal & SVE
TCE TCE SVE
TCE
TCE
PCE Cr6
TCE
Capital Region of Denmark (CRD) • Investigate, • Risk assess • Prioritize • Remediate
Two sites are undergoing remedy at the moment: • Klintehøj Vænge 16, soil vapor
extraction (SVE), ongoing • Pilehøj Vænge 10, Thermal
and SVE, ongoing • Hammerbakken 10 are in the
making and will be started shortly
The contaminated sites in the northern part of BIA poses a threat to 2 major drinking water supplies
TCE Thermal
SVE on Klintehøj Vænge 16
• 4 wells in the unsaturated sand
• Air exchange rate 40 m³/h well
• Based on a pumping test where
pneumatic conductivity of the
sand as well as the leakage of
the sandy clay-till was
determined
• Design parameter where a total
air exchange rate of appr. 1000
PV/year below Klintehøj Vænge
16
12. september
2018
8
V2
V1
V3
V4
SVE on Klintehøj Vænge 16 - 1
12. september
2018
9 TCE removal rate in average appr. 13 kg/y
SVE on Klintehøj Vænge 16 - 2
12. september
2018
10 PCE removal in average 24 kg/y, 8,5 kg TCE/y now
PCE Concentration (µg/m³) in the wells Sept.
2017
12. september
2018
11
12000
76000 6
16
Known & probable polluted sites in BIA
TCE
TCE TCE
TCE
TCE
PCE Cr6
TCE
Red hatch: Known pollution (V2 register) Blue hatch: Suspected pollution (V1 register) Yellow arrow: Overall groundwater flow direction appr 10 m/y Bold characters are known major sources
Blokken 25
TCE
Modelling
• The two SVE plants ran at
different times with different flow
• Particle tracking analysis done
with variations in the
hydraulic/pneumatic parameters
(radial, homogenous scenarios,
transient in time)
• Conclusions
– Theoretical possible that
particles from Blokken 25 could
arrive at Klintehøj Vænge 16
after 2 years
– Suspicious that the observed
amount originate from Blokken
25 12. september
2018
13
Modelled pressure distribution (Pa) and particle tracking trajectories
CSIA sampling and analysis
• Compound Specific Isotope
Analysis (CSIA) can be used to
distinguish between sources
• Different isotope pairs can be
used, typically 13C/12C, 37C/35Cl, 2H/1H, 18O/16O, 15N/14N
• Measured by GC-MS with special
equipment (commercially
available for some isotopes)
12. september
2018
14
Composition statistically different. Klintehøj Vænge 16 less degraded
A new set of wells and sampling
12. september
2018
15
PCE in soil gas (µg/m³) in deep sand
PCE in top groundwater (µg/l) in deep sand
Area under suspicion
Back in the archives once more
• New historical reviews done on
the properties located within the
blue ring
– Minor use of solvents –
probably most TCE
– No known/suspected PCE
source based on the reviews
• The none hatched properties
within the ring has probably not
used solvents, based on a
screening done before the
reviews
• Investigation ongoing – reports
in the making
12. september
2018
16
Its warming up…….
12. september
2018
17
PCE in soil gas (µg/m³) in deep sand
PCE in top groundwater (µg/l) in deep sand
Area under suspicion
Whats next…..
12. september
2018
18
• Maybe the pollution detection dog
• Thorough soil gas investigation near surface in area of interest
• Possibly followed by drilling to get soil samples for a mass estimate
• Decision making – is running the SVE enough or….
Inside the halls
Wrap up
• Old industrial area with lots of
sources
• Already screened for major
sources early on
• PCE suddenly turns up in SVE
designed for a TCE site
• One known PCE source in area –
unlikely to be the origin based on
direction flow, intuition and
general knowledge of SVE
operation
• Modelling shows a theoretical
impact, mass flux probably
unrealistic
• CSIA shows different origin of
PCE in extracted air and the
known source
• Two round of new wells and
sampling of deep soil gas and
water narrows down area of
interest
• Area needs to be pin-pointed
more (now appr. 2500 m²)
before a mass estimate can be
made
• Decision making about the
future of the SVE operation
12. september
2018
19