Steam Enhanced Remediation

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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
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Visalia Pole Yard
160,000 gallons removed from subsurface In-situ
destruction significant UC Berkeley LLNL - SCE
Creosote DNAPL to 140 ft depth Alluvial sands
and gravels with clays Both LNAPL and
DNAPL Approaching MCLs in 2002 Craig Eaker, SCE
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Alameda Point
Alameda Point (Berkeley Environmental Restoration
Center)
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Edwards AFB Site 61
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Beale AFB
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Loring Fractured limestone
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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)

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Well types
Perimeter steam injection wells (SI)
Extraction well with Hawthorn electrode (EE)
Area A steam injection well with Hawthorn
electrode (SE)
Deep electrode (DE)
Steam
Electrode
Sand
Clay
Electrode
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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

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Fractured granite (quartz monzonite)
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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?

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Hydrogeology
Weathered zone
30 ft
Fractured granite
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TCE distribution
?
?
?
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Vertical distribution of contaminants before
operations PID readings on cores
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Extraction and steam injection wells
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Injection well design
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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
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Subsurface monitoring network
VEA-2
VEA-4
EW-3
TMA-D
EW-4
TMA-C
IW-1
VEA-5
TMA-B
EW-1
EW-2
TMA-A
VEA-3
VEA-1
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ERT data planes
ERT data planes
VEA-2
VEA-4
VEA-5
VEA-3
VEA-1
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Example ERT data plane
6/23
6/27
6/10
7/6
7/10
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Thermocouple data
Depth below grade (ft)
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Depth below grade (ft)
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Depth below grade (ft)
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Water balance
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Energy balance
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Vapor flow rate and PID readings
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Headspace PID data
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Recovery of NAPL
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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