Enhancing Natural Attenuation through Bioaugmentation with Aerobic Bacteria that Degrade cis-1,2-Dichloroethene
Abstract
Monitored natural attenuation (MNA) and enhanced in situ bioremediation (EISB) remedies hold the promise of reducing the costs associated with the cleanup of Department of Defense (DoD) sites impacted by chlorinated solvents. However, there are many DoD sites where tetrachloroethene (PCE) and trichloroethene (TCE) are undergoing only partial dechlorination to cis-1,2-dichloroethene (cDCE), even when sufficient electron donor is present either because of the absence of required bacteria (Dehalococcoides) or aerobic conditions. Under SERDP sponsorship (ER-1168), a novel aerobic bacterium (Polaromonas sp. strain JS666) that uses cDCE as a sole carbon and energy source was isolated and characterized (Coleman et al., 2002a,b). Since it requires no exotic growth factors, JS666 is a promising bioaugmentation culture for aerobic sites where cDCE is recalcitrant. The microorganism will grow and thrive where oxygen and cDCE are co-located, and JS666 also degrades 1,2- dichloroethane (DCA) and cometabolizes TCE and vinyl chloride (VC). Ideal groundwater conditions for JS666 include: dissolved oxygen (DO) levels between 0.01 mg/L and 8 mg/L; low ionic strength (conductivity <15 milliSiemens per centimeter [mS/cm]); a pH of 6.5 to 8; and relatively low concentrations of TCE, 1,2-DCA and VC (<500 g/L). The goal of this first field demonstration was to evaluate the effectiveness of JS666 in biodegrading cDCE. The demonstration was conducted at Site 21, St. Julien s Creek Annex in Chesapeake, Virginia. This site had several relatively well-characterized groundwater plumes of chlorinated volatile organic compounds (VOCs; primarily cDCE, TCE and VC), appropriate site conditions, and a suitable on-site support network. In the vicinity of the pilot test area, groundwater flow is towards the west. Shallow groundwater typically ranges from 2 to 7 ft below ground surface (bgs).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2010
- Accession Number
- ADA604013
Entities
People
- Carol Aziz
- Dave Major
- James Gossett
- Jim C. Spain
- Mark Watling
- Shirley Nishino
Organizations
- Geosyntec Consultants (United States)