Previous environmental applications of partitioning tracer tests to detect and quantify nonaqueous phase liquid (NAPL) contamination in the subsurface have been limited to well-to-well tests. However, theory and numerical modeling suggests that single-well injection-extraction ("push-pull") partitioning tracer tests can also potentially detect and quantify NAPL contamination. In this type of te...

The effectiveness of removal of nonaqueous phase liquids (NAPLs) from the entrapment source zone of the subsurface has been limited by soil heterogeneity and the inability to locate all entrapped sources. The goal of this study was to demonstrate the uncertainty of degree of source removal associated with aquifer heterogeneity. In this demonstration, source zone NAPL removal using surfactant-en...

cally, water is assumed to be immobile at the residualwater saturation. In the petroleum industry, the residAt many contaminated sites, nonaqueous phase liquids (NAPLs) ual-water saturation is also called the irreducible-water persist in the vadose zone for long periods of time. This occurs because the permeability of the NAPL becomes negligible at some saturation saturation. This terminology h...

North American railroads transport a wide variety of chemicals, chemical mixtures and solutions in railroad tank cars. In the event of an accident, these materials may be spilled and impact the environment. Among the chemicals commonly transported are a number of light non-aqueous phase liquids (LNAPLs). If these are spilled they can contaminate soil and groundwater and result in costly cleanup...

Thermal remediation techniques, such as hot water flooding, are emerging technologies that have been proposed for the removal of nonaqueous phase liquids (NAPLs) from the subsurface. In this study a combined laboratory and modeling investigation was conducted to determine if hot water flooding techniques would improve NAPL mass removal compared to ambient temperature water flushing. Two experim...

A simple dissolution model based on Raoult's Law was used to derive a log-linear equation for the estimation of multicomponent nonaqueous-phase liquid (NAPL) mass in porous media. The analysis, referred to here as the ratio mass estimation (RME) method, requires aqueous concentration ratios for two components of the NAPL mixture as well as their pure phase liquid solubilities. Application of th...

Nonaqueous phase liquid (NAPL) contaminants that are chemical mixtures often contain compounds that are solids in their pure states. In the environment, weathering processes cause shifts in multicomponent NAPL composition, thereby enriching the NAPL in the less soluble compounds which may result in their eventual solidification. In this paper, we review the thermodynamic theory governing solid–...

A pore network model with cubic chambers and rectangular tubes was used to estimate the nonaqueous phase liquid (NAPL) dissolution rate coefficient, Kdissai, and NAPL/water total specific interfacial area, ai. Kdissai was computed as a function of modified Peclet number (Pe') for various NAPL saturations (SN) and ai during drainage and imbibition and during dissolution without displacement. The...

This study develops a modeling approach for simulating and evaluating entrapped light nonaqueous-phase liquid (light NAPL-LNAPL) dissolution and transport of the solute in a fractured permeable aquifer (FPA). The term FPA refers to an aquifer made of porous blocks of high permeability that embed fractures. The fracture network is part of the domain characterized by high permeability and negligi...

The removal of malathion from soil by surfactant washing was investigated under various physical-chemical states of the malathion. Three distinctive phases (without nonaqueous phase liquids (NAPL), with NAPL, and the transitional zone of NAPL) were found to be important for a better understanding of the washing process. When there is no NAPL in the system, the washing process is less dependent ...