Important tools in the toolbox - Renare Mark · • Henrys law constant increases ... than 99.9% at...
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Transcript of Important tools in the toolbox - Renare Mark · • Henrys law constant increases ... than 99.9% at...
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StockholmStockholmHelsinkiHelsinki
OdenseOdense WarszwaWarszwa
AalborgAalborgÅÅrhusrhus
EsbjergEsbjerg KKøøbenhavnbenhavn
KrakKrakóóvv
PoznanPoznan KiKiéévv
SofiaSofia
1050 colleques
250 environmentalists
Tom HeronDivision Director, geologist
Thermally enhancedremediation
In Situ Thermal Desorption
Joakim Andersson
Karin Tornberg
Emma Evertsson
Ebba Svanström
Important tools in the toolbox
• Heavily contaminated source zones• Stringent remediation requirements• Fast clean-up• Large volumes• Clay/silts/fractured• Deep contamination• Many contaminants and mixtures
Source zone
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• Chlorinated Ethenes• Oil products, BTEX• Coal Tar• Creosote• PAH’s, Naphthalene• PCB’s• Chlorobenzenes• Pentachlorophenol (PCP)• Dioxins• Mercury• Many pesticides• Mixtures
Treatable contaminants
Data on much of this in NIRAS’ and Krügers booth up stairs!!
Remediation Mechanisms
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• Boiling point in multiphase system and steam-drive
Mechanisms and values for TCE
• Vapor pressure increases• TCE: 18 times for 10 - 100 °C
• Henrys law constant increases• TCE: 12 times for 25 - 100 °C
• The enthalpy of sorption decreases• TCE: 20 % from 10 - 100 °C
• In Situ degradation
• Viscosity, interfacial tensions and densityreduced: ~ 1 – 2 times
Liquid
Gas Phase25
20
15
10
5
00 20 40 60 80 100
TCE
Nafthalene
TemperatureoC
R
Boiling point in a two phase system
1,50
1,25
1,00
0,75
0,50
0,25
0,00
0 20 40 60 80 100 120 140
Water + PCE
Water
PCE
Pres
sure
(atm
)
Temperature oC
87 121
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Technologies
SEE - heating governed by hydraulic conductivity – non-uniform steam flow
ERH - heating governed by electrical conductivity
ISTD/TCH - heating governed by thermal conductivity – nearly uniform distribution of heat
Important Heating Technologies - Summary
Electrical
Conductive
Steam
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In Situ Thermal Desorption and destruction
Heater-OnlyWell
Heater-VacuumWell
To Off-Gas Treatment Unit
Volatilization and Destruction of Contaminants
Target T: 100oC to 300oC
Very Hot Thermal Destruction Zone300oC to 700oC
Off-Gas Residence Time Several Hours
1 to 2 feet 1 to 2 feet
Important design issues:
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• Goals / effect on risk or value• Time• Price
• Liquid and vapor capture• Condensation fronts• Boiling water is expensive• Temperature distribution• Energy balance• Organic rich soils• Underground utilities / buildings etc.
Important design issues
Examples of completed projects
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UC Berkeley
TCE: 2 mg/kg og 5 µg/l
Typical chromatogram:Soil before Steam
After thermal treatment
Naval Air Station Alameda, Site 5, San Francisco
Goal: MCL in soil and groundwater for BTEX og chlorinated solvents
Motor oil
TCE,
BTE
X, e
tc
Courtesy of Kent S. Udell
ISTD – Free phase PCE in tight alluvial clay
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0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
Soil
Con
cent
ratio
n - u
g/kg
PCE TCE cis-1,2-DCE VC
AVG PostRemedial GoalsAVG Pre
2,000 2,000
17,000
23012 < RL 65 5
34,222
1,055
6,650
932
99.96% 99.63% 99.03% 99.49%Reductions:
Results are based on 17 pre-treatment and 64 post-treatment samples
Results – Average concentrations
Ongoing Danish Projects
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Knullen – Odense, Denmark
Worlds first thermal remediation using af combinationof steam and ISTD
TTZ
COC’s: PCE, chlorinatedsolvents (800 kg)
Soil: Clay and sand
Treatment interv.: 3 – 14 m.b.g.
Area: 240 m2
Volume: 1.900 m3
Estimated cost: 15 mio. dkr
Number of HV-borings: 45
Steam injection wells: 5
Steam extraction wells: 2
All wells installed under a building
Skuldelev – Denmark
Full-scale design based on results from pilot testCOC’s: PCE, chlorinatedsolvents (4000 kg)
Soil: Clay and sand
Treatment depth: 7,5 meters
Area: 250 m2
Volume: 1.600 m3
Estimated cost: 12 mio. dkr
ISTD-wells: 53
Vacuum wells: 21
Water extraction wells: 3
Building
Sheet piling
TTZ
Lake
ISTD-heater
Water extraction boring
Vacuum boring
Pilot test, Skuldelev
Monitoring well, Skuldelev
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Ongoing projects
Reerslev – DenmarkCOC: PCE – 10.000 kg
Soil: Clay
Treatment depth: 8 meters
Area: 900 – 4.700 m2
Netherlands – Confidential siteCOC: Diesel (mass currently unknown)
Soil: Fractured limestone
Treatment depth: 6,5 meters
Area: 100 – 3.500 m2
Design based on treatability study –indicated remediation efficiencies better than 99.9% at treatment temperatures between 100 and 200 °C.
OvenFlow of nitrogen
Condensing system Temperature measurements
OvenFlow of nitrogen
Condensing system Temperature measurements
Test setup – laboratory experiments
? ?
? ?
ThankThank youyou and:and:
[email protected]+45 87323256+45 21418302
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Component property Oil based LNAPL
Chlorinated solvents Creosote Coal tar PCB Comment
Vapor pressure increase factor 20-40 20-40 20-40 20-40 20-40 Abundance of data in literature
Solubility increase factor 2-100? 1.5-3 10-1000 10-1000 10-1000Chlorinated solvent less affected than larger hydrocarbons
Henry's constant increase factors 10-20 0-10 0-10 0-10
Data absent for most compounds, some decrease?
Viscosity reduction factor 2 to 100+ 1.3-3 5-10 20-100+ 3-100 The higher initial viscosity, the more reduction
Interfacial tension reduction factor <2 <2 2-5 1-5 <5 Typically not dramatic effect (less than
factor 2)
Density reduction (%) 10-20 10-20 10-20 10-20 10-20 Note that DNAPL may become LNAPL
Kd (reduction factor) ? 1-10 5-100 5-100 NA Estimates based on limited data
Udell (1989, 1991, 1993, 1996). Davis (1997, 1999).Imhoff et al. (1997).Sleep and Ma (1997).Heron et al. (1998, 2000).
Physical processes/changes (below 120 °C)
Energy consumption (kWh/m3)
91117219347Heating to 200 ºC
4369171299Heating to 100 ºC & evaporating all porewater
43476180Heating to 100 ºC, wet
0 %10 %80 %100 %
Initial water content
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100 -120 oC partial removal (ERH, SEE, ISTD low int.)300 oC complete removal (ISTD, dewater)
100-120 oC(ERH, SEE, ISTD)
Below water table
300 oC(ISTD)
90-100 oC(ERH, SEE, ISTD)
Above water table
SVOCVOC
Target temperatures
ERH: Electrical Resistivity HeatingSEE: Steam Enhanced ExtractionISTD: In Situ Thermal Desorption
In Situ Thermal Desorption
PCB´s
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< 0.17800PCB 1254Ferndale, CA
< 110,000PCB 1254/1260Saipan, NMI
< 0.0332,200PCB 1254/1260Vallejo, CA
< 0.03320,000PCB 1260Cape Girardeau, MO
< 0.85,000PCB 1248/1254S. Glens Falls, NY
Final Concentration
(ppm)
Initial Max. Concentration
(ppm)
ContaminantLocation
Source: Stegemeier and Vinegar (2001)Terratherm Inc.
ISTD: PCB Field Projects - Results
ISTD
PAH´s and Dioxins
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Soil:Fill, Silt with clay lenses and sand stringers
Woodtreatment facility, Alabama
0
100,000
200,000
300,000
400,000
500,000
600,000
Soil
Con
cent
ratio
n - u
g/kg
PCE TCE cis-1,2-DCE VC
Max PostRemedial GoalsMax Pre
2,000 2,000 17,000 230
44 < RL 1,500 24
510,000
6,500
57,000
6,500
99.96% 99.63% 99.03% 99.49%Reductions:Results are based on 17 pre-treatment samples and 64 post-treatment samples.
Post-treatment samples were collected from centroids (i.e., coolest locations) at random and biased depths (15 or 23% were collected between 18 and 20 ft bgs).
Results – Maximum concentrations
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Steam Zone
Sand Pack
HO Well
Mod. To high K
Tight clay/Bay
mud
DNAPL
In-Situ Temperatures
ISTD: Remediation concept
oC
1.8 –3.0 m
3.0 –4.9 m
4.9 –6.1 m
Centroi
250
354
275
200
101
101
102
94
101
96
9978
0 –1.8 m
HeaterCentroid1.8 m1.8 m
1.2 m 0.6 m 1.2 m
y
101
9496
78
101
102
101
99
250
354
275
200
1.8 –3.0 m
3.0 –4.9 m
4.9 –6.1 m
Centroi
250
354
275
200
101
101
102
94
101
96
9978
0 –1.8 m
HeaterCentroid1.8 m1.8 m
1.2 m 0.6 m 1.2 m
y
101
9496
78
101
102
101
99
250
354
275
200
Horizontal Vapor Collection Screen