For this project ARCADIS is demonstrating the procedures for its In-situ Reactive Zone (IRZ) technology to remediate chlorinated aliphatic hydrocarbons (CAH) and metals. Though the primary requirement of the selected demonstration sites is in-situ treatment of CAHs, this technology can also be successfully implemented for certain metal contaminants. Advantages of this innovative in-situ groundwater remediation alternative include significant reduction in the cost of remediation and the remedial time frame. The IRZ demonstration proposed here involves the addition of a harmless solution of sugars and sulfur, which serve as a supplemental energy source for microbiological processes in the subsurface. Through subsurface molasses injection existing aerobic or mildly anoxic aquifers will be transformed into highly anaerobic reactive zones creating suitable conditions for the biodegradation of CAHs. Ultimately, the results of the demonstration will furnish design parameters to be used to estimate the costs associated with a full scale IRZ implementation and develop a protocol for using the IRZ technology for CAHs at DoD facilities.
This program is funded and overseen by the Air Force Center For Environmental Excellence (AFCEE) and the Environmental Security Technology Certification Program (ESTCP).
An initial characterization of biogeochemical conditions and a feasibility evaluation for implementation of this technology has been performed at each facility. Three of these sites will then be selected for this demonstration (one as a "beta test") following preparation of a protocol for this approach. The bases that have been selected for demonstrations represent a broad array of geologic conditions ranging from coastal plain sands to glacial silts and bedrock. Therefore, the sites vary in geochemistry as well. This will provide insight on the range of sites where the technology can be applied. Similarly, the sites were chosen to evaluate the success of the IRZ approach at addressing contaminants at both relatively high and low concentrations. The primary goal of these technology demonstrations is to use them to develop a protocol for use of the IRZ technology for CAHs at DoD facilities.
ARCADIS has successfully managed a series of minor issues during the execution of this project to date including:
- Very thorough demonstration plan questions from a wide variety of stakeholder reviewers - those employed by ESTCP, bases, other contractors and regulators.
- Difficult drilling conditions requiring changes in drilling techniques.
- Difficult field conditions including a brush fire in the vicinity of the field site at Vandenberg AFB.
n Intensive and extensive regulatory negotiations with federal, state, and local authorities.
- Coordination of three laboratories (one central analytical and two specialty labs) and multiple drilling contractors.
Project Highlights
Management – This project has required regulatory negotiation skills to obtain acceptance of injection of the molasses reagent in three state jurisdictions. It has also required seamless coordination of three laboratories (one central analytical laboratory and two specialty labs) and multiple drilling subcontractors. We have also recently presented the demonstration project to community leaders at Vandenberg AFB and it was well received.
Technical – As discussed above, although this is not a task order contract, activities are being conducted simultaneously at three widely geographically separated locations coordinated by a single ARCADIS project manager. This project spotlights a technology - enhanced in situ biodegradation in which ARCADIS is an acknowledged leader in the commercial marketplace. This project requires seamless integration of skills in microbiology, geology, environmental chemistry and engineering.
