Three sources of contamination have resulted in groundwater quality
impacts at the New Mexico Department of Transportation (NMDOT) Las Vegas Service
Center in Las Vegas, New Mexico. Leaking underground storage tanks, leaking
distribution piping, and formerly unlined, salted cinder storage have contaminated
groundwater with petroleum hydrocarbons, 1,1,1-trichloroethane (TCA), and total
dissolved solids (TDS), respectively. The plumes are distinct at the source areas, but
commingle downgradient. The low permeability of the shallow water-bearing zone
makes groundwater extraction via wells impractical due to low production rates. The
nature of the commingled contaminants and low permeability of the subsurface, were
considered in the selection of an extraction and ex-situ treatment remedy for
contaminated groundwater. Because a trench has greater access to contaminant flow
pathways (fractures and bedding planes) than a single, or multiple wells, trench-based
dual phase extraction (DPE) was piloted to evaluate its ability to dewater a significantly
larger volume of the subsurface, and to provide a higher groundwater production rate
than extraction wells. During a 2-week pilot test, the DPE trench achieved a steady state
groundwater extraction rate of approximately 2.5 gallons per minute (gpm). This
pumping rate represents an average groundwater extraction rate 10 times greater than was
attainable with the previous multi-well groundwater extraction system. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 830 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 8 |
| Published : | 06/17/2005 |
