Objective:
Partitioning electron donors (PED) are electron donors that partition directly into the dense nonaqueous phase liquid (DNAPL), promoting the growth of dechlorinating biomass close to the DNAPL and enhancing DNAPL dissolution rates. The objective of this project is to demonstrate and validate the application of a PED to improve the biologically enhanced dissolution rate of DNAPLs and ultimately to reduce costs associated with the application of electron donors in source zones. Technology Description: This project involves both laboratory and field evaluations. The laboratory assessment will screen the suitability of the candidate PEDs and collect key data that will be used to design the PED field application. The field application will involve loading a DNAPL area with a PED by injecting and intermittently recirculating the PED through the source area. The recirculation system will allow efficient loading of the DNAPL with the PED and give the operator control over achieving the desired target loading. The degree of PED loading into the DNAPL will be assessed by measuring the change in aqueous phase concentration of the PED. The properties of the PEDs allow for short duration application (less than their degradation rate) and periodic recirculation for approximately 1 month. Efforts will be made, however, to select a demonstration site with appropriate groundwater velocity that eliminates the need for recirculation and allows for a passive approach to achieve the desired PED loading. Expected Benefits: Successful application of this technology will significantly enhance the performance of bioremediation to treat DNAPL source zones in shorter time frames and with reduced costs. The PED approach is fully compatible with biobarrier establishment through biostimulation and bioaugmentation to achieve plume control, thus allowing broad implementation at Department of Defense sites. Furthermore, existing pump-and-treat systems could be retrofitted to create a small biological degradation/containment zone in and around the source area, eliminating or significantly reducing the amount of water extraction required to maintain containment (and associated costs) while reducing the overall treatment time. (Anticipated Project Completion - 2011) Principal Investigator: Ms. Carmen Lebrón Naval Facilities Engineering Service Center Restoration Development Branch 1100 23rd Avenue, ESC-411 Port Hueneme, CA 93043-4370 Telephone: (805) 982-1616 Fax: (805) 982-4304 E-mail: carmen.lebron@navy.mil
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