Launch Complex 39B (LC39B) is a NASA launch site located at the Kennedy Space Center in Florida. LC39B was constructed in the mid-1960s for the Apollo Space Program, retrofitted in the mid-1970s to support the space shuttle operations, and is currently being reconfigured by NASA for future Orion missions to Mars.
Resource Conservation and Recovery Act (RCRA) Facility Investigations and supplemental assessment activities by Geosyntec identified dissolved chlorinated volatile organic compound (CVOC) groundwater impacts encompassing an area of approximately 27 acres. Following the completion of a feasibility study, a combination of monitored natural attenuation (MNA) and air sparging was selected to address the groundwater impacts. The air sparge design targeted an approximate nine-acre area where CVOC concentrations were not anticipated to decrease via natural attenuation in a timely manner. Design objectives included: (i) treating the CVOC impacted areas to facilitate a clear transition to long-term monitoring (exit strategy); (ii) completing the remediation in a short time frame (less than three years) due to NASA's proposed launch schedule; (iii) reducing the amount of time needed to complete routine operations and maintenance (O&M) activities; and (iv) reducing the amount of time needed to complete routine O&M activities.
Geosyntec's Scope of Services
Geosyntec's design for the air sparge system following the completion of the feasibility study included:
- 279 air sparge wells screened across various depth intervals, with a maximum depth of approximately 52 feet below land surface, representing the largest known air sparge system operating in the eastern United States
- 32 manifold enclosures for air distribution to the air sparge wells, with metering equipment to allow for the efficient adjustment and optimization of air flow to individual air sparge wells
- an air compressor system with a 100-horse power oil-injected rotary screw compressor to provide air to the subsurface in a pulsed/zone configuration and a control panel to allow for on-site and remote adjustments to system operations
- a network of monitoring wells within the treatment area to assess remedy performance over time
Upon completion of the design, Geosyntec procured the air compressor system, oversaw the installation of all components of the air sparge system, and successfully completed system startup activities. Monthly O&M activities, quarterly performance monitoring, and routine optimization activities have been conducted following startup.
The air sparge system installation, which included the completion of over three miles of trenching and the installation of over five miles of piping, was completed with no safety incidents. During air sparge well installation, soil cores were collected from the bottom 10 feet of each air sparge well location to identify the depth of low-permeability soils, which allowed for the refinement of individual air sparge well depths to maximize air distribution. Within six months of air sparge system startup, groundwater monitoring results have documented an average reduction in groundwater concentrations of over 90%, with an anticipation that exit-strategy objectives will be met in less than two years.