VII Seminário Internacional Sobre Remediação e Revitalização de Áreas Contaminadas São Paulo, 21.10.2010, 1/7 VII Seminário Internacional Sobre Remediação e Revitalização de Áreas Contaminadas São Paulo, 21.10.2010 Dr.-Ing. Uwe Hiester (reconsite GmbH) Dr.-Ing. Hans-Peter Koschitzky, Dipl.-Ing. (FH) Oliver Trötschler (VEGAS – Research Facility for Subsurface Remediation, Uni Stuttgart) Dr.-Ing. Frank Holzer, Dr.-Ing. Ulf Roland (Helmholtz Centre for Environmental Research, Leipzig) Thermally Enhanced In Situ Source Zone Removal 21. Oct. 2010 Seite 2 Thermally enhanced in situ source zone removal Oilphase 21. Oct. 2010 Seite 3 Thermally enhanced in situ source zone removal • in-situ source removal • organic contaminants boiling point up to app. 200°C • LNAPL & DNAPL • non cohesive & cohesive soil • unsat. & satur. zone Silt DNAPL LNAPL Groundwater Loam Sand Application of thermally enhanced in-situ remediation 21. Oct. 2010 Seite 4 Thermally enhanced in situ source zone removal 0,01 0,1 1 10 100 0 14 28 42 56 70 84 98 112 126 140 154 Time [d] CVOC-Mass Flux from Source Zone 1 [kg/d] 'cold' SVE Okt.1998 - Mar.1999 'cold' SVE June 2009 Comparison ‘cold‘ SVE with THERIS 21. Oct. 2010 Seite 5 Thermally enhanced in situ source zone removal Comparison ‘cold‘ SVE with THERIS 0,01 0,1 1 10 100 0 14 28 42 56 70 84 98 112 126 140 154 Time [d] CVOC-Mass Flux from Source Zone 1 [kg/d] 'cold' SVE Okt.1998 - Mar.1999 'cold' SVE June 2009 THERIS (only SB26) June-Okt. 2009 21. Oct. 2010 Seite 6 Thermally enhanced in situ source zone removal Conventional ‘cold‘ SVE Altenbockum et al. 1997 groundwater sand sand, filling loam, marl, silt conta- mination SVE continuous operation intermittent operation concentration concentration time time initial concentration c 0 conventional soil vapor extraction (SVE): usually several years of operation
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VII Seminário Internacional Sobre Remediação e Revitalizaçãode Áreas Contaminadas São Paulo, 21.10.2010, 1/7
VII Seminário Internacional SobreRemediação e Revitalizaçãode Áreas Contaminadas
São Paulo, 21.10.2010
Dr.-Ing. Uwe Hiester (reconsite GmbH)Dr.-Ing. Hans-Peter Koschitzky, Dipl.-Ing. (FH) Oliver Trötschler (VEGAS – Research Facility for Subsurface Remediation, Uni Stuttgart)Dr.-Ing. Frank Holzer, Dr.-Ing. Ulf Roland (Helmholtz Centre for Environmental Research, Leipzig)
Thermally Enhanced In Situ Source Zone Removal
21. Oct. 2010 Seite 2Thermally enhanced in situ source zone removal
Oilphase
21. Oct. 2010 Seite 3Thermally enhanced in situ source zone removal
• in-situ sourceremoval
• organiccontaminantsboiling point up to app. 200°C
• LNAPL & DNAPL
• non cohesive & cohesive soil
• unsat. & satur. zone
Silt
DNAPLLNAPL
Groundwater
Loam
Sand
Application of thermally enhanced in-situ remediation
21. Oct. 2010 Seite 4Thermally enhanced in situ source zone removal
0,01
0,1
1
10
100
0 14 28 42 56 70 84 98 112 126 140 154
Time [d]
CVO
C-M
ass
Flux
from
Sou
rce
Zone
1 [k
g/d]
'cold' SVE Okt.1998 - Mar.1999'cold' SVE June 2009
Comparison ‘cold‘ SVE with THERIS
21. Oct. 2010 Seite 5Thermally enhanced in situ source zone removal
Comparison ‘cold‘ SVE with THERIS
0,01
0,1
1
10
100
0 14 28 42 56 70 84 98 112 126 140 154
Time [d]
CVO
C-M
ass
Flux
from
Sou
rce
Zone
1 [k
g/d]
'cold' SVE Okt.1998 - Mar.1999'cold' SVE June 2009THERIS (only SB26) June-Okt. 2009
21. Oct. 2010 Seite 6Thermally enhanced in situ source zone removal
Conventional ‘cold‘ SVE
Altenbockum et al. 1997groundwater
sand
sand, filling
loam, marl, silt
conta-mination
SVE
continuousoperation
intermittentoperation
conc
entr
atio
n
conc
entr
atio
n
time time
initialconcentration c0
conventional soil vapor extraction (SVE):usually several years of operation
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21. Oct. 2010 Seite 7Thermally enhanced in situ source zone removal
Thermally enhanced SVE
groundwater
sand
sand, filling
loam, marl, silt
conta-mination Target:
• liquid contaminant (10 °C)⇒ gaseous phase
• short remediation time
THERIS = Thermally enhanced in-situ remediation with thermal wells
HE HE
SVETHE: 500°C • soil vapor extraction (SVE)
• air treatment system
21. Oct. 2010 Seite 8Thermally enhanced in situ source zone removal
200
300
400
500
600
700
800
900
1000
60 80 100Temperature [°C]
Stea
m P
ress
ure
[mba
r]
Tetra-chloro-ethen (PCE)
co-boilingPCE and Water
Water
Boiling of water and contaminant phase
∼ 60%
0
200
400
600
800
1000
0 25 50 75 100 125Temperature [°C]
Stea
m P
ress
ure
[mba
r]
Tetra-chloro-ethen (PCE)
co-boilingPCE and Water
Water
21. Oct. 2010 Seite 9Thermally enhanced in situ source zone removal
Thermally enhanced in-situ remediation
• convective heat supply into soil layer withgood to high permeability e.g. sand
Steam- (Air-) Injection (TUBA-method)
• direct heat generation e.g. in dry or humid sand
Radio frequency
• conductive heat supply into soil layer moderate to low soil permeablility, e.g. silt, loam, clay
Thermal wells (THERIS-method)
21. Oct. 2010 Seite 10Thermally enhanced in situ source zone removal
Steam-Air Injection: Field of Applicationvadoze zone:high to medium permeability(gravel to sandy silt)
saturated zone:porous aquifersK: 5 x 10-5 to 1 x 10-3 m/s(sand -> silt) for
thermal range in saturated zone:
K: 0,5 – 5 x 10-4 m/s radial steam propagation:
3 - 5 m in radius for 150 kg/h steam (120 kW)
the higher anisotropy thewider steam propagation
21. Oct. 2010 Seite 11Thermally enhanced in situ source zone removal
test field after completion of
installation (February 2007)
test field during operation (June 2007)
injection well
Remediation goals of the pilot in-situ remediationhorizontal radial steam expansion > 2.5 m in the saturated zonereduction of benzene concentration in soil vapor > 99%removal of contaminant mass > 95%
to be achieved during six months (1600 m³ of soil)
Zeitz - Impressions From The Pilot Field
21. Oct. 2010 Seite 12Thermally enhanced in situ source zone removal
1„cold“SVE
2air-
sparging
3 steam-air-injection
4 cooling (SVE)
target temperature
target average temperature in subsurface > 75°C
Zeitz - Heating Of The Subsurface
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21. Oct. 2010 Seite 13Thermally enhanced in situ source zone removal
I1o + I2o + I3o +EK3 SAI (I1u) SAI (I1u+I2u) --> entire field intermittent and pulsingair venting, sparging + SVE
ASI1
UZ (silt)SVE + SAI
Air Venting
Air Sparging
target reduction of benzene concentration in soil vapor > 99%
Zeitz - Mass Extraction of Benzene by SVE
21. Oct. 2010 Seite 15Thermally enhanced in situ source zone removal
reduction of benzene concentration in SVE by 99% removal of more than 99% in soil (soil vapour-soil eq. KOC-method)0.16 mg benzene / kg soilsoil sampling eight months after steam-air injection confirmed 0.1 mg/kg for unsaturated zone and 0.5 mg/kg including saturatedzone
Indication of Remediation Progress by SVE
21. Oct. 2010 Seite 16Thermally enhanced in situ source zone removal
effective heating to exceed target temperatureeffective, fast & wide-ranging steam propagation in saturated zone
Heating of Subsurface
mass extraction by „cold“ SVE and air-sparging (59% of total mass) remediation target achieved by SI (35% of total mass in 13 weeks)minor mass of Benzene in saturated zone: approximately 300 kg (~ 4%)
Remediation Progress
mass removal: more than 99% of Benzene extracted (6,75 to Benzene)groundwater: reduction of benzene concentrations by 75%
Remediation goals
Zeitz - Summary
21. Oct. 2010 Seite 17Thermally enhanced in situ source zone removal
Applied electrode geometries- Parallel plate or net-shaped electrodes- Arrays of rod-like electrodes(optional: also used as extraction wells)
- Radio-wave antenna
Similar to microwave ovenfast re-orientation of polar molecules(e.g. water) or other polar structuresin the external electrical field
interaction within the materialheat formation
OH
Hδ+ δ− δ− δ+
- + + -OH
Hδ+ δ− δ− δ+
- + + -
RFgenerator
Match-box
380 V 50 Hz
T>250°Cpossible
13.56 MHz
Set up and working principle of dielectric soil heating
21. Oct. 2010 Seite 18Thermally enhanced in situ source zone removal
RF unit
RF generator(15 kW, 13.56 MHz)
Cooling system
Process control system
Fibre-opticalsensors
Gas analysis
Power measurement
PLF supply(12 kW, 50 Hz)
RF unit
Flexible PE - Hose
Measuring section V, T, p, c
Manifold
RF
-
Shielding
ElectrodeE1
ElectrodeE5
Matchbox
Coaxialcable
Catalyticoxidation
RF unit
RF generator(15 kW, 13.56 MHz)
Cooling system
Process control system
Fibre-opticalsensors
Gas analysis
Power measurement
PLF supply(12 kW, 50 Hz)
RF unit
Flexible PE - Hose
Measuring section V, T, p, c
Manifold
RF
RF unit
Flexible PE - Hose
Measuring section V, T, p, c
Manifold
RF
-
Shielding
ElectrodeE1
ElectrodeE5
Matchbox
Coaxialcable
Catalyticoxidation
coaxial cablesensors for p, T, V, c
.
shielding
matchbox
up to 50 temperature sensors9 points for vapour sampling
4 electrodes / extraction wells
Arrangement for ISRFH project
3 mElectrodedistance
ISRFH with a modular RF system
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21. Oct. 2010 Seite 19Thermally enhanced in situ source zone removal
RW electrode and extraction section(200 mm diameter)
- 5.8 m
-5.3 m
-3.8 m
Filtration sand
Bore hole Ø273 mm
FRP pipeØ 237 mm
- 0.50 mConcrete
Bentonite
RW electrode and extraction section(200 mm diameter)
- 5.8 m
-5.3 m
-3.8 m
Filtration sand
Bore hole Ø273 mm
FRP pipeØ 237 mm
- 0.50 mConcrete
Bentonite
Electrode / extraction wellSite characterization
Soil: very inhomogeneous
Groundwater table: 8.5 m bgl.
Lignite: > 9 m bgl.
Treatment of the unsaturatedzone between 3 and 7 m bgl.
Contamination:mainly benzene < 3.5 g/kgvariety of aromatic andaliphatic VOC
ISRFH – new electrode design
21. Oct. 2010 Seite 20Thermally enhanced in situ source zone removal
0 20 40 60 80 100 120 1400
50
100
150
200
250
300
20
40
60
depth
3 m5 m7 m
VOC
con
c.or
g. C
/ m
3
Time / days
Start RF heating
Tem
pera
ture
/ °C
-5 -4 -3 -2 -1 0 1 2 3 4 57
6
5
4
3
2
1
0
Distance from the RF-Electrode / m
Dep
th /
m
0
20
40
60
80
100
Tem
pera
ture
/ °C
Temperature profile
Heat transport supported by SVERadius of influence up to 5 m
VOC concentrationTemperature distribution in a soil volume of about 300 m3 after 60 d RF heating with 15 kW
Increase in VOC concentrationby a factor of 4 to 8
ISRFH with a modular RF system
21. Oct. 2010 Seite 21Thermally enhanced in situ source zone removal
The demonstration project consisted of three stages:1. „cold“ SVE (24 days), 2. RF heating alone (18 days)3. combined SVE + RFH (36 days)
App. 300 m3 were heated to a mean temperature of 54°C.
The radius of influence for RF heating was about 5 m.
SVE supported heat transport in the soil.
Extraction of VOCs was significantly enhanced by heating althoughquantification was difficult due to interference with the soil around thedemonstration site (1.3 tonnes were eliminated).
ISRFH – Main Results
21. Oct. 2010 Seite 22Thermally enhanced in situ source zone removal
Site D: BTEX-petr. hydrocarbon remediation
groundwater
sand
filling
clayey finesand
THERIS-remediation
21. Oct. 2010 Seite 23Thermally enhanced in situ source zone removal
Site D: BTEX-petr. hydrocarbon remediation
surroundingSVE-wells
Thermal wells
central SVE-wells
21. Oct. 2010 Seite 24Thermally enhanced in situ source zone removal
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21. Oct. 2010 Seite 25Thermally enhanced in situ source zone removal
64 d THERIS
Factor 100 inmass recovery
21. Oct. 2010 Seite 26Thermally enhanced in situ source zone removal
THERIS mass removal'cold' SVE mass removal (extrapolation)furhter operation time with 'cold' SVE to recover the THERIS contaminant mass (supposed constant mass flux for cold SVE)
Monday, 30.07.2008:
min. 54 month (=4.5 years) further 'cold' SVE operation needed to recover the same mass from THERIS pilot test
THERIS BTEX-remediation
additional costs for ‘cold‘ SVE to recover the same contaminant mass:
constant mass flux ~ 4,5 years ~ 120.000 £
half mass flux (av. over time) ~ 9 years ~ 300.000 £
21. Oct. 2010 Seite 27Thermally enhanced in situ source zone removal
Remediation Area
21. Oct. 2010 Seite 28Thermally enhanced in situ source zone removal
THERIS application
workshop
storeage
office
parkingarea
shop
21. Oct. 2010 Seite 29Thermally enhanced in situ source zone removal
Workshop Area
21. Oct. 2010 Seite 30Thermally enhanced in situ source zone removal
Street View
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21. Oct. 2010 Seite 31Thermally enhanced in situ source zone removal
Treatment Container
21. Oct. 2010 Seite 32Thermally enhanced in situ source zone removal
Online Measurement Systems
21. Oct. 2010 Seite 33Thermally enhanced in situ source zone removal
Online Measurement Systems
21. Oct. 2010 Seite 34Thermally enhanced in situ source zone removal
d] total CHC mass flux sumtotal CHC mass flux BL5total CHC mass flux BL4total CHC mass flux BL3total CHC mass flux BL2total CHC mass flux BL1total CHC mass flux BL2btotal CHC mass flux BL1b