VOC Remediation Under Active Manufacturing Facility - Marietta, GA
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LMM11 ShortV ProjEx 2012-0425 VOC Remediation Under an Activ e Manufacturing Facility Lockheed Martin Airforce Plant 6 - Marietta, GA Project Summary TRS Group, Inc. ( TRS), working with Atlanta Environmental Management (AEM), performed electrical resistance heating (ERH) at hangar building B-84 at the operating Lockheed Martin Aeronautics (LMA) manufacturing facility in Marietta, Georgia. The LMA facility is also known as Air Force Plant 6 and is used to manufacture new aircraft and rehabilitate preexisting models. The B-84 building was previously used in the storage and maintenance of various aircraft which included a degreasing area in the western most area of the hangar. A release of volatile organic compounds (VOCs) including tetrachloroethene (PCE), 1,1,1-trichloroethane (TCA), 1,1-dichloroethene (DCE) and xylene occurred from the degreasing pit. During the ERH project, the B-84 building was undergoing modifications to accommodate larger aircraft. The ERH treatment area focused on the former degreasing area. The remediation goal for ERH area at this site was to achieve a 95% reduction in VOC concentrations in soil over a 6 month period. The ERH treatment system was i nstalled prior to a new 18 inch thick concrete s lab being poured as the hangar floor. Prior to ERH, the initial maximum concentration was 847 mg/kg with a site average of approximately 6 mg/kg. Background The site is located at building B-84 at the Lockheed Martin Air force Plant 6 location in Marietta, Georgia. The B - 84 building was used as an aircraft hangar and staging area during the manufacturing process. Previous activities included use of a degreasing area in the western most portion of the building. Initially, soil contamination was detected during a utility repair under the B-84 building slab in the vicinity of the degreasing area. Further delineation of the building and surrounding area identified the source area and su bsequent remediation volume. Prior to ERH installation, a major portion of the original building floor was removed. The upper two feet of top soil was determined to be an incompetent substrate for the new floor. The two feet of top soil was replaced with a graded aggregate backfill (GAB). Soil type is described as silty clay with fine to medium sands and is typically referred to as Saprolite. Groundwater was encountered below 18 feet bgs. Site Characteristics & Design Parameters The ERH treatment area was approximately 4400 square feet (ft 2 ) in area. The depth of the treatment volume was from below slab or 2 feet to 20 feet bgs. The total volume of the ERH treatment region was 3 100 cubic yards. TRS based the system design to heat the subsurface and maintain suitable temperatures for 180 days applying 800,000 kW hours of energy in the process. The electrodes were designed to apply this energy safely and without excessive dry out by including subsurface rehydration capability. Vapor collection was based upon providing 20 co-located electrode VR vents to safely and efficiently remove air, steam and soil vapors from the subsurface. The resulting recovered steam condensate was utilized as cooling water and drip hydration water during the process. The vapor treatment design was based upon the estimated 90 pounds of recovered soil vapors requiring 2000 pounds of vapor phase GAC assuming a conservative GAC loading. A list of key design considerations ar e listed below in no order of priori ty: • Maintain site and public safety at all times; • Design a system that would safely and efficiently operate beneath an occupied facility. • Recover and convey VOC vapors and steam to the above grade treatment systems; • Treat recovered vapors and steam to acceptable discharge limits; • Measure subsurface temperatures, vacuum, and air flow; • Sample and analyze recovered vapors for monitoring system performance; • Perform the installation of ERH equipment and remediation in a compressed time frame; • Quickly heat the treatment area to efficiently remove VOCs from the subsurface
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LMM11 ShortV ProjEx 2012-0425
VOC Remediation Under an Active Manufacturing FacilityLockheed Martin Airforce Plant 6 - Marietta, GA
Project Summary
TRS Group, Inc. (TRS), working with Atlanta Environmental Management (AEM), performed electrical resistanceheating (ERH) at hangar building B-84 at the operating Lockheed Martin Aeronautics (LMA) manufacturing facilityin Marietta, Georgia. The LMA facility is also known as Air Force Plant 6 and is used to manufacture new aircraftand rehabilitate preexisting models. The B-84 building was previously used in the storage and maintenance of various aircraft which included a degreasing area in the western most area of the hangar. A release of volatileorganic compounds (VOCs) including tetrachloroethene (PCE), 1,1,1-trichloroethane (TCA), 1,1-dichloroethene(DCE) and xylene occurred from the degreasing pit. During the ERH project, the B-84 building was undergoingmodifications to accommodate larger aircraft. The ERH treatment area focused on the former degreasing area.The remediation goal for ERH area at this site was to achieve a 95% reduction in VOC concentrations in soil overa 6 month period. The ERH treatment system was installed prior to a new 18 inch thick concrete slab beingpoured as the hangar floor. Prior to ERH, the initial maximum concentration was 847 mg/kg with a site average
of approximately 6 mg/kg.
Background
The site is located at building B-84 at the Lockheed Martin Air force Plant 6 location in Marietta, Georgia. The B-84 building was used as an aircraft hangar and staging area during the manufacturing process. Previous activitiesincluded use of a degreasing area in the western most portion of the building. Initially, soil contamination wasdetected during a utility repair under the B-84 building slab in the vicinity of the degreasing area. Furtherdelineation of the building and surrounding area identified the source area and subsequent remediation volume.Prior to ERH installation, a major portion of the original building floor was removed. The upper two feet of top soilwas determined to be an incompetent substrate for the new floor. The two feet of top soil was replaced with agraded aggregate backfill (GAB).
Soil type is described as silty clay with fine to medium sands and is typically referred to as Saprolite. Groundwaterwas encountered below 18 feet bgs.
Site Characteristics & Design Parameters
The ERH treatment area was approximately 4400 square feet (ft2) in area. The depth of the treatment volumewas from below slab or 2 feet to 20 feet bgs. The total volume of the ERH treatment region was 3100 cubicyards. TRS based the system design to heat the subsurface and maintain suitable temperatures for 180 daysapplying 800,000 kW hours of energy in the process. The electrodes were designed to apply this energy safelyand without excessive dry out by including subsurface rehydration capability. Vapor collection was based upon
providing 20 co-located electrode VR vents to safely and efficiently remove air, steam and soil vapors from thesubsurface. The resulting recovered steam condensate was utilized as cooling water and drip hydration waterduring the process. The vapor treatment design was based upon the estimated 90 pounds of recovered soil
vapors requiring 2000 pounds of vapor phase GAC assuming a conservative GAC loading.
A list of key design considerations are listed below in no order of priority:
• Maintain site and public safety at all times;
• Design a system that would safely and efficiently operate beneath an occupied facility.
• Recover and convey VOC vapors and steam to the above grade treatment systems;
• Treat recovered vapors and steam to acceptable discharge limits;
• Measure subsurface temperatures, vacuum, and air flow;
• Sample and analyze recovered vapors for monitoring system performance;
• Perform the installation of ERH equipment and remediation in a compressed time frame;
• Quickly heat the treatment area to efficiently remove VOCs from the subsurface
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LMM11 ShortV ProjEx 2012-0425
©2012- TRS Group®, Inc. All rights reserved.
System Construction/Operations
Construction and subsurface installation of the ERH system began on March 24, 2011 with mobilization of the
drilling equipment and subsurface materials to the site and a pre-construction safety and kickoff meeting with AEM and LMA. Subsurface construction included the installation of 20 electrodes and four TMP’s. Installation wasachieved using a 12-inch outside diameter hollow stem auger. The installation of electrodes and TMPs wascompleted on March 31, 2011. Installation of the horizontal vapor recovery points, subsurface neutral and linerbegan on April 4, 2011 and was completed on April 13, 2011. The new 18 inch concrete floor was poured overthe treatment area by the hanger construction contractor, Swofford Construction.
Installation of the surface portion of the ERH system began on April 25, 2011 with the delivery and placement of
the TRS owned 500 kW PCU, condenser, cooling tower and vacuum blower. Surface piping, electrical terminationsand system integration was completed on May 4, 2011.
Results
Confirmatory soil sampling was conducted by AEM starting on August 24, 2011 at the 70% completion point of ERHsystem operations based on time and energy. Based on analytical reports provided by AEM, the ERH system reducedthe total VOC soil concentration within the treatment area (shown graphically below) by 99.2% at the 70%completion point. Additional confirmatory sampling was conducted at the 100% completion point of the project and
the total VOC concentrations were reduced to a final percent reduction of 98.5%.
Summary
Site Geology and Hydrology Silty clay with fine to medium sands. Groundwater, 18 ft bgs
Treatment Area Size, Volume, and Depth 4,400 ft 2 ; 3,100 yd
3 ; 2 to 20 ft bgs
Beginning Maximum Contaminant Concentrations Soil: 847 mg/kg total CVOCs initial maximum concentrations
Remedial Goal(s) Soil: Reduce total VOCs in soil by 95% within 6 months of operations.
Reduction Achieved 98.5% total VOCs in soil
Period of Performance 180 days of operation
Contract Terms Standard Fixed Price Remediation
TRS Contact InformationMr. David Fleming, (425) 396-4266, [email protected] , www.thermalrs.com
