In-Situ Enhanced Biodegradation Injections

In-Situ Enhanced Biodegradation Injections, Camp Bullis, Joint Base San Antonio (JBSA), San Antonio, TX – Air Force Civil Engineer Center (AFCEC)

KGS/Trinity performed remedial injections of emulsified vegetable oil (EVO) substrate into five horizontal injection wells beneath a former landfill site to remediate chlorinated hydrocarbon impacts in groundwater.  Initial field efforts included jetting of the injection wells and a video camera survey to ensure that the wells were clear and useable for EVO injection after 11 years of inactivity. Daily operations included transporting water from a potable water source approximately 5 miles from the site, mixing 5,000-gallon batches of potable water and EVO in specified proportions, and pumping the batches in alternating injection wells.  A microbial consortium of Dehalococcoides mccartyi, designed to anaerobically degrade PCE and TCE, was injected at two intermediate stages using nitrogen to pressurize the substrate for injection while maintaining anaerobic conditions necessary for the survival and effectiveness of the bacterial consortium.  Pumping activities were projected to take up to seven weeks based on previous well performance.  However, adjustments made by the project team to the injection well heads allowed for injection of the complete volume of 125,000 gallons of EVO in just 19 days, more than four weeks ahead of schedule.