3 Matching Results

Search Results

Advanced search parameters have been applied.

Application of a NAPL partitioning interwell tracer test (PITT) to support DNAPL remediation at the Sandia National Laboratories/New Mexico chemical waste landfill

Description: Chlorinated solvents as dense non-aqueous phase liquid (DNAPL) are present at a large number of hazardous waste sites across the U.S. and world. DNAPL is difficult to detect in the subsurface, much less characterize to any degree of accuracy. Without proper site characterization, remedial decisions are often difficult to make and technically effective, cost-efficient remediations are even more difficult to obtain. A new non-aqueous phase liquid (NAPL) characterization technology that is superior to conventional technologies has been developed and applied at full-scale. This technology, referred to as the Partitioning Interwell Tracer Test (PITT), has been adopted from oil-field practices and tailored to environmental application in the vadose and saturated zones. A PITT has been applied for the first time at full-scale to characterize DNAPL in the vadose zone. The PITT was applied in December 1995 beneath two side-by-side organic disposal pits at Sandia National Laboratories/New Mexico (SNL/NM) RCRA Interim Status Chemical Waste Landfill (CWL), located in Albuquerque, New Mexico. DNAPL, consisting of a mixture of chlorinated solvents, aromatic hydrocarbons, and PCE oils, is known to exist in at least one of the two buried pits. The vadose zone PITT was conducted by injecting a slug of non-partitioning and NAPL-partitioning tracers into and through a zone of interest under a controlled forced gradient. The forced gradient was created by a balanced extraction of soil gas at a location 55 feet from the injector. The extracted gas stream was sampled over time to define tracer break-through curves. Soil gas sampling ports from multilevel monitoring installations were sampled to define break-through curves at specific locations and depths. Analytical instrumentation such as gas chromatographs and a photoacoustical analyzers operated autonomously, were used for tracer detection.
Date: May 1, 1996
Creator: Studer, J.E.; Mariner, P. & Jin, M.
Partner: UNT Libraries Government Documents Department

In-situ characterizations of dense non-aqueous phase liquids using partitioning tracers. Annual progress report, September 15, 1996--September 14, 1997

Description: 'This paper describes laboratory research conducted to investigate the use of partitioning tracers for the detection, volume estimation, and remediation performance assessment of vadose zones contaminated by nonaqueous phase liquids (NAPLs). These laboratory studies used Ottawa sand and field soil packed columns. The columns were saturated, then reduced to residual saturations of water and NAPL, creating a three phase system of air, water, and NAPL. Conservative and partitioning gas tracers were injected into the column and their elutions were analyzed. The method of moments was used to estimate partition coefficients between the air and NAPL phases for each of the tracers. The partition coefficients and retardation factors are used to select appropriate tracers for NAPL detection and volume estimation in the field. This research identified several perfluorocarbon tracers suitable for use in the field and demonstrated the feasibility of using partitioning tracers as a tool for NAPL detection and volume estimation in the vadose zone.'
Date: January 23, 1998
Creator: Pope, G.A.; McKinney, D.C.; Gupta, A.D.; Jackson, R.E. & Jin, M.
Partner: UNT Libraries Government Documents Department