MPE/SVE REMEDIATION SYSTEM
HUNTSVILLE, ALABAMA

LBG engineers excel at working closely with our clients to meet both required environmental and business objectives associated with site remediation. LBG is currently installing a combination multi-phase extraction (MPE) and soil vapor extraction (SVE) system designed to remediate trichloroethane and dichloroethene impacted soil and ground water at on operating electronics assembly facility. The site had several limitations, which had to be integrated into the system design to ensure that the system would be successful. These limitations included:

• Complex layering of relatively impermeable clays with more permeable layers of chert and clay. Pilot test data indicated pneumatic permeability of the soil ranged from 10-7 to 10-9 cm2.
  
  
• The measured radius of influence of ground-water extraction measured during pilot testing was limited to 15 feet. 
   
• The area which required treatment is located under an outdoor storage area used by the electronics facility and must remain accessible during installation and operation of the system.

The final result of this type of cooperation and planning is a remediation system that is capable of meeting the site clean-up criteria while minimizing both cost and operational impact to the electronics facility.

The LBG engineers and geologists working with the client developed an innovative design to remediate the impacted soil and ground water while minimizing the impact to the facility. These design parameters include:

• Performing an electrical conductivity (EC) investigation of the site to determine the location of the more permeable layers.
  
  
• Designing the combination MPE\SVE extraction points as 30 nested pairs with the screened interval of the points matched to the location of the more permeable zones as shown by the EC investigation.
  
  
• The MPE system was designed to extract ground water at between 0.5 and 2.0 gallons per minute and air at 50 to 75 actual cubic feet per minute. The SVE system will extract air at between 50 acfm and 75 acfm.
  
  
• The operating strategy is to use the MPE system to dewater the formation and then apply the SVE system to extract the VOC’s from the exposed soil.
  
  
• To minimize the impact of installation on the operation of the facility, the points were manifolded together at three separate locations with only a main pipe from each manifold to the equipment location. This design allowed the use of stationary equipment while eliminating the need to bring all 120 pipes required by the system to a single large manifold saving piping costs and disruption to plant operations.