Air and Ozone Sparging of TCE Using a Directionally Drilled Horizontal Well Site 86, Camp Lejeune

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Air and Ozone Sparging of TCE Using a
Directionally Drilled Horizontal WellSite 86,
Camp Lejeune

• Mark Strong, P.E. CH2M HILL
• Christopher Bozzini, P.E. CH2M HILL
• Daniel Hood, NAVFAC Mid-Atlantic
• Bob Lowder, MCB Camp Lejeune EMD

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Camp Lejeune Background

• Second largest U.S. Marine Corps Base in the
  Country
• Camp Lejeune was established near the city of
  Jacksonville, N.C, in 1942.
• Base covers 236 square miles
• CERCLA site since 1989
• 22 Operable Units (OUs), 97 Sites.

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Site Location and History

• Site 86 is associated with three former waste oil
  ASTs, used during the 70s and 80s
• Over the course of several investigations since
  1992, the solvent plume migrated away from the
  source area and now extends several hundred feet
  off-site

Bld. 25
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Pilot Test Objectives

• Prevent further migration of the TCE plume
  off-site
• Evaluate air (and ozone) distribution using a
  horizontal well
• Determine if ozone and/or air sparging can reduce
  TCE impacts to below regulatory standards within
  one year

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TCE in Plume in 2002 (30-35 bgs)
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TCE in Plume in 2002 (40-45 bgs)
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TCE in Plume in 2002 (50-55 bgs)
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Site 86 Cross Section
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Directional Drill Rig On-Site
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Air Sparge Screen
4 SDR 11 HDPE Pipe 0.020 Inch Wide Slots 0.5
Open Area
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Directional Sparge Well Layout
Total Length of Drill 950 Total Slotted Length
- 350
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Compressor and Ozone Generator Temporary
Buildings (Connex Boxes)
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Ozone Generator Chiller
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Air Compressor, Receiver, Gas Cooler
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Ozonia Generator (CFV-03, 60 ppd, air feed)
Photo courtesy Ozonia North America
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Baseline TCE Concentrations, Feb 05 30-35 ft bgs
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Baseline TCE Concentrations, Feb 05 40-45 ft bgs
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Baseline TCE Concentrations, Feb 05 50-55 ft bgs
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Schedule

• Three Months of Air Sparging (120-140 cfm)
• One Month of Rebound Monitoring
• Six Months of Ozone Enhanced Air Sparging ( 7000
  ppmv)
• Three Months of Rebound Monitoring (Recently
  Completed)

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Ozone Injection Performance

• Ozone production began in late July, 2005
• Intermittent operation from July to December
• Mechanical issues desiccant dryer and chiller
• Total aggregate run time 2-1/2 months (50 up
  time)
• Total mass of ozone delivered 3900 pounds

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Average TCE ConcentrationsZone A Monitoring
Wells (30-35 Screen Depth)
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Average TCE ConcentrationsZone B Monitoring
Wells (40 - 45 Screen Depth)
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Average TCE ConcentrationsZone C Monitoring
Wells (50 - 55 Screen Depth)
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Discussion

• SVE was not conducted because of low permeability
  overburden trace levels of TCE measured in
  shallow vapor during operation (ppbv)
• Air was diverted horizontally by overburden air
  bubbling was observed 300 feet from the well
• Lateral propagation of air fingering was
  estimated to be 50 feet on either side of the
  well, as indicated by dissolved oxygen
  concentrations
• Negligible increases in dissolved chloride from
  baseline levels

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Conceptual Model
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Example Dissolved Oxygen and ORP Trend
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Summary of Analytical Data
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Conclusions

• 90 average reduction of TCE within three months
  in wells with baseline TCE gt 50 µg/L
• 99 average reduction within one year in wells
  with baseline TCE gt 50 µg/L
• No significant rebound after three months
  (greater than 25 µg/L)
• Distance of influence 50 ft on both sides of
  the well (as indicated by DO measurements)
• Possible contribution of ozone to TCE mass
  reduction inconclusive - low TCE concentrations
  and limited period of operation

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Summary of Costs

• 750K Total Budget
• Horizontal Well, Compressed Air System,
  Container, Electrical 250K
• Ozone System and Container 300K
• Monitoring 100K
• OM 100K