Phyto remediation groundwater trends at the DOE portsmouth gaseous
- CDM, Piketon, OH (United States)
This paper describes the progress of a phyto-remediation action being performed at the Department of Energy (DOE) Portsmouth Gaseous Diffusion Plant (PORTS) X-740 Waste Oil Handling Facility to remediate contaminated groundwater under a Resource Conservation and Recovery Act (RCRA) closure action. This action was effected by an Ohio Environmental Protection Agency (OEPA) decision to use phyto-remediation as the preferred remedy for the X-740 groundwater contamination. This remedy was recognized as a cost-effective, low-maintenance, and promising method to remediate groundwater contaminated with volatile organic compounds (VOCs), primarily trichloroethylene (TCE). During 1999, prior to the tree installation at the X-740 Phyto-remediation Area, water level measurements in the area were collected from 10 monitoring wells completed in the Gallia Formation. The Gallia is the uppermost water-bearing zone and contains most of the groundwater contamination at PORTS. During the tree installation which took place during the summer of 1999, four new Gallia monitoring wells were installed at the X-740 Area in addition to the 10 Gallia wells which had been installed in the same area during the early 1990's. Manual water level measurements were collected quarterly from these 14 Gallia monitoring wells between 1998 and 2001. These manual water level measurements were collected to monitor the combined impact of the trees on the groundwater prior to root development. Beginning in 2001, water level measurements were collected monthly during the growing season (April-September) and quarterly during the dormant season (October-March). A total of eight water level measurements were collected annually to monitor the phyto-remediation system's effect on the groundwater in the X- 740 Area. The primary function of the X-740 Phyto-remediation Area is to hydraulically prevent further spreading of the TCE plume. This process utilizes deep-rooted plants, such as poplar trees, to extract large quantities of water from the saturated zone. The focus of any phyto-remediation system is to develop a cone of depression under the entire plantation area. This cone of depression can halt migration of the contaminant plume and can create a hydraulic barrier, thereby maintaining plume capture. While a cone of depression is not yet evident at the X-740 Phyto-remediation Area, water level measurements in 2004 and 2005 differed from measurements taken in previous years, indicating that the now mature trees are influencing groundwater flow direction and gradient at the site. Water level measurements taken from 2003 through 2005 indicate a trend whereby groundwater elevations steadily decreased in the X-740 Phyto-remediation System. During this time, an average groundwater table drop of 0.30 feet was observed. Although the time for the phyto-remediation system to mature had been estimated at two to three years, these monitoring data indicate a period of four to five years for the trees to reach maturity. Although, these trends are not apparent from analysis of the potentiometric surface contours, it does appear that the head gradient across the site is higher during the spring and lower during the fall. It is not clear, however, whether this trend was initiated by the installation of the phyto-remediation system. This paper will present the groundwater data collected to date to illustrate the effects of the trees on the groundwater table. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 21294665
- Report Number(s):
- INIS-US-09-WM-07127; TRN: US10V0080040855
- Resource Relation:
- Conference: WM'07: 2007 Waste Management Symposium - Global Accomplishments in Environmental and Radioactive Waste Management: Education and Opportunity for the Next Generation of Waste Management Professionals, Tucson, AZ (United States), 25 Feb - 1 Mar 2007; Other Information: Country of input: France; 7 refs
- Country of Publication:
- United States
- Language:
- English
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