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Green Remediation ofPetroleum ContaminatedGroundwater Using OxygenInjection in Western MaineBrian Bachmann, CGKeith Taylor...
IntroductionTypically in Maine, petroleum contaminationis remediated utilizing:    • techniques that don’t take into accou...
Soil Excavation• Environmental  impacts from  excavator, trucks,  recycling plant:   ° Air emissions   ° Fossil fuel     c...
Pump and Treat• Groundwater extraction and  treatment systems (GETS)  are used for sensitive  groundwater resources.• Envi...
Natural Attenuation• Allows hydrocarbons to  biodegrade completely on  their own; we only monitor• Low-carbon footprint• B...
Site Description
Site Description• Contamination first  documented in 2004.• Free product diesel fuel  present, but erratic in  location an...
Hydrogeology• Glaciofluvial, deltaic, and  eolian sand deposits  mapped in area.• Soil borings at site  penetrated up to 3...
Hydrogeology
Contamination Approximate  Extent ofContamination
Remedial Goals• The goal of remediation was to reduce the  high concentrations of dissolved petroleum  downgradient of the...
Remediation• Certain conditions lead to choosing oxygen  injection:    – High permeability (easy for oxygen to move)    – ...
Remediation• Evidence of anaerobic biodegradation:   – Low DO, SO4, NO3 in the middle of the plume   – High Fe, Methane, H...
Remediation                      Sulfate (ppm)St.Germain Collins
Remediation                        • 10 oxygen injection wells                          installed:                        ...
System Design                          • Each well connected                            to the oxygen source              ...
Oxygen Source and Delivery                     • Cylinder connected to a                       manifold designed to       ...
Contamination Approximate  Extent ofContamination
Initial Groundwater Quality• In January 2011,  impacts dominated  by volatile petroleum  hydrocarbons (VPH)• Highest total...
Operation and Maintenance• The system ran for six months without  interruption.• Visit the site every two weeks, install n...
Dissolved Oxygen Trends• System operated without problems from  January 2011 until shutdown in June 2011.• Background DO l...
Groundwater Quality at System              Shutdown                     • By June 2011, total                       VPH at...
Groundwater Quality 2 Months             After Shutdown• In August 2011, 2 months after system  shutdown, another round of...
Groundwater Quality 2 Months      After Shutdown                   • Very little                     rebound              ...
How Green are these         technologies?              IN SITU              BIODEGRADATION?DIG?PUMP?
For More Information Contact:St.Germain Collins846 Main Street, Suite 3Westbrook, ME 04103info@stgermaincollins.com(207) 5...
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Green Remediation - 2012 Maine Water Conference

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Typically in Maine, petroleum contamination is remediated utilizing techniques that don’t take into account energy consumption or the overall “carbon footprint” of the remedial option. Soil excavation is the most common method, while groundwater extraction and treatment is used for sensitive groundwater resources. Trucking contaminated soil has the obvious environmental impacts of fuel consumption and air emissions. Pump and treat groundwater systems consume large amounts of electricity for pumps and filters, and often generate wastes that requires special disposal.

At a site in western Maine, St.Germain Collins designed and implemented a green technology for groundwater treatment that consumed no electricity, generated no waste, and had a carbon footprint limited to vehicle use for periodic site visits. This system was based on the fact that petroleum hydrocarbons in groundwater are degraded by microbes naturally present in the subsurface. Biodegradation is often limited by a lack of oxygen, and to accelerate the process, St.Germain Collins installed a ten well oxygen injection system.

The effectiveness of the system was monitored by sampling five wells known to be contaminated. Before system startup, groundwater impacts were dominated by volatile petroleum hydrocarbons (VPH) with a high of 11,961 ug/L. After six months of operation, VPH at the same location was reduced to 4,599 ug/L. A similar pattern was observed across the Site with no significant rebound observed two months after system shutdown. Because of its effectiveness and minimal environmental impact, oxygen injection should be considered as a viable remedial method for petroleum contaminated groundwater in Maine.

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  • Typically in Maine, petroleum contamination is remediated utilizing techniques that don’t take into account energy consumption or the overall “carbon footprint” of the remedial option. Soil excavation is the most common method, while groundwater extraction and treatment is used for sensitive groundwater resources. Trucking contaminated soil has the obvious environmental impacts of fuel consumption and air emissions. Pump and treat groundwater systems consume large amounts of electricity for pumps and filters, and often generate wastes that requires special disposal.
  • The groundwater flow path has consistently been to the north-northeast, but the water table elevations have fluctuated up to seven feet since 2003.
  • The groundwater flow path has consistently been to the north-northeast, but the water table elevations have fluctuated up to seven feet since 2003.
  • The groundwater flow path has consistently been to the north-northeast, but the water table elevations have fluctuated up to seven feet since 2003.
  • Transcript of "Green Remediation - 2012 Maine Water Conference"

    1. 1. Green Remediation ofPetroleum ContaminatedGroundwater Using OxygenInjection in Western MaineBrian Bachmann, CGKeith Taylor, CG2012 Maine Water ConferenceMarch 14, 2012
    2. 2. IntroductionTypically in Maine, petroleum contaminationis remediated utilizing: • techniques that don’t take into account energy consumption, or • the overall “environmental footprint” of the remedial option.St.Germain Collins
    3. 3. Soil Excavation• Environmental impacts from excavator, trucks, recycling plant: ° Air emissions ° Fossil fuel consumption St.Germain Collins
    4. 4. Pump and Treat• Groundwater extraction and treatment systems (GETS) are used for sensitive groundwater resources.• Environmental Impacts from GETS: ° High electricity needs ° Air emissions ° Waste from pretreatment and post treatment (e.g., iron removal)St.Germain Collins
    5. 5. Natural Attenuation• Allows hydrocarbons to biodegrade completely on their own; we only monitor• Low-carbon footprint• But it takes a very long time--some sites have been monitored since the 1990s.• Monitoring for decades still requires vehicle usage St.Germain Collins
    6. 6. Site Description
    7. 7. Site Description• Contamination first documented in 2004.• Free product diesel fuel present, but erratic in location and thickness.• Also mixed diesel and gasoline dissolved phase contamination.• Petroleum fingerprinting indicates both old and new contamination.St.Germain Collins
    8. 8. Hydrogeology• Glaciofluvial, deltaic, and eolian sand deposits mapped in area.• Soil borings at site penetrated up to 30 feet of interbedded fine to coarse sand with minor silt.• No clay or low permeability material. St.Germain Collins
    9. 9. Hydrogeology
    10. 10. Contamination Approximate Extent ofContamination
    11. 11. Remedial Goals• The goal of remediation was to reduce the high concentrations of dissolved petroleum downgradient of the site.• DEP were primarily concerned with vapor migration and free product.• Owner wanted to reduce dissolved phase concentrations to reduce vapor risk• A clean site was not the goal.St.Germain Collins
    12. 12. Remediation• Certain conditions lead to choosing oxygen injection: – High permeability (easy for oxygen to move) – Deep water table (precluded soil excavation) – Relatively inexpensive, small carbon footprint – Strong evidence of anaerobic biodegradation.• Aerobic biodegradation is more efficient at removing petroleum hydrocarbons.St.Germain Collins
    13. 13. Remediation• Evidence of anaerobic biodegradation: – Low DO, SO4, NO3 in the middle of the plume – High Fe, Methane, Heterotrophic Plate Count (bacteria) in the middle of the plume Dissolved Oxygen (ppm) St.Germain Collins
    14. 14. Remediation Sulfate (ppm)St.Germain Collins
    15. 15. Remediation • 10 oxygen injection wells installed: • 4 up-gradient of source • 6 down-gradient of source • 1-inch diameter • 3 feet of 200-micron micro- porous screen at the bottom • 30-foot depthSt.Germain Collins
    16. 16. System Design • Each well connected to the oxygen source by 0.25-inch tubing sealed in road cut • Oxygen source is 200-pound liquid oxygen cylinder.St.Germain Collins
    17. 17. Oxygen Source and Delivery • Cylinder connected to a manifold designed to regulate the amount of oxygen delivered to each well.St.Germain Collins
    18. 18. Contamination Approximate Extent ofContamination
    19. 19. Initial Groundwater Quality• In January 2011, impacts dominated by volatile petroleum hydrocarbons (VPH)• Highest total VPH level in January 2011 was 11,961 ug/L at MW-10. St.Germain Collins
    20. 20. Operation and Maintenance• The system ran for six months without interruption.• Visit the site every two weeks, install new liquid O2 tank, collect monitoring well measurements.• All site visits were coordinated with company supplying oxygen. They were already traveling to the area so additional trip was not needed.St.Germain Collins
    21. 21. Dissolved Oxygen Trends• System operated without problems from January 2011 until shutdown in June 2011.• Background DO levels before system startup were 1 to 3 mg/l.• DO level of 40 mg/l was measured at well MW-11 on May 27, 2011.• Aquifer had become highly oxygenated, even within the plume.St.Germain Collins
    22. 22. Groundwater Quality at System Shutdown • By June 2011, total VPH at MW-10 had been reduced to 4,599 ug/L. • 62% reduction at MW-10 • 84% reduction at MW-9.St.Germain Collins
    23. 23. Groundwater Quality 2 Months After Shutdown• In August 2011, 2 months after system shutdown, another round of groundwater samples were collected.• Wanted to assess potential for rebound.• Rebounding of contaminant concentrations common in groundwater remediation.• Reflects a return to equilibrium conditions.St.Germain Collins
    24. 24. Groundwater Quality 2 Months After Shutdown • Very little rebound • Total VPH reduced an average of 61%
    25. 25. How Green are these technologies? IN SITU BIODEGRADATION?DIG?PUMP?
    26. 26. For More Information Contact:St.Germain Collins846 Main Street, Suite 3Westbrook, ME 04103info@stgermaincollins.com(207) 591-7000
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