Nonaqueous-phase liquid

The majority of trichloroethylene present on soil surfaces will volatilize to the atmosphere or leach into the subsurface. Once trichloroethylene leaches into the soil, it appears not to become chemically transformed or undergo covalent bonding with soil components. When trichloroethylene was absorbed onto kaolinite and bentonite, the nuclear magnetic resonance (NMR) spectra showed no evidence of chemical reactions (Jurkiewicz and Maciel 1995). Because trichloroethylene is a dense nonaqueous phase liquid, it can move through the imsaturated zone into the saturated zone where it can displace soil pore water (Wershaw et al. 1994). 

Ghoshal S, RG Luthy (1996) Bioavailability of hydrophobic organic compounds from nonaqueous-phase liquids the biodegradation of naphthalene from coal tar. Environ Toxicol Chem 15 1894-1900. 

As an immiscible organic liquid retained by capillary forces in the pore space between the soil particles. This free organic phase is often referred to with the abbreviation NAPL (nonaqueous phase liquid). 

The formation of semirigid films around nonaqueous-phase liquids (NAPL) with a high resistance to NAPL-water mass transfer... 

Besides petroleum products, other hazardous substances (see Tables 18.7-18.9) are also stored in USTs. Among them, a common and important group is the dense nonaqueous phase liquids (DNAPLs). This group has some different physical properties from petroleum (especially gasoline) that make them behave differently in the way they move underground. This section presents the important factors associated with the cleanup of DNAPLs. 

An insoluble liquid or gas will separate from water, resulting in immiscible-phase separation. The behavior of nonaqueous-phase liquids (NAPLs) that may be lighter (LNAPLs) or denser (DNAPLs)... 

Palmer, C.D. and Johnson, R.L., Physical processes controlling the transport of nonaqueous phase liquids in the subsurface, in Transport and Fate of Contaminants in the Subsurface, EPA 625/4-89/019, U.S. EPA, Washington, 1989. 

High airflow rates may result in unintended fracturing leading to nonuniform flow or short-circuiting of injected air in the subsurface, or may result in unintended mobilization of contaminants as nonaqueous phase liquids (NAPL), dissolved in groundwater, or in soil gas. 

Carroquino, M.J. and M. Alexander. 1998. Factors affecting the biodegradation of phenanthrene initially dissolved in different nonaqueous-phase liquids. Environ. Toxicol. Chem. 17 265-270. 

Microbes were frequently found to synthesise surface-active molecules in order to mobilise hydrophobic organic substrates. These biosurfactants, which are either excreted by the producing organisms or remain bound to their cell surfaces, are composed of a hydrophilic part making them soluble in water and a lipophilic part making them accumulate at interfaces. With respect to their physical effects, one can distinguish two types of biosurfactants firstly, molecules that drastically reduce the surface and interfacial tensions of gas-liquid, liquid-liquid and liquid-solid systems, and, secondly, compounds that stabilise emulsions of nonaqueous phase liquids in water, often also referred to as bioemulsifiers. The former molecules are typically low-molar-mass... 

Dense metal membranes, 15 800 Dense nonaqueous phase liquids... 

Nonaqueous phase liquids (NAPLs), 3 766 in soil and ground water treatment, 25 834... 

Hunt JR, Sitar N, Udell KS. 1988. Nonaqueous phase liquid transport and cleanup 1. Analysis of mechanisms. Water Resources Research 24(8) 1247-1258. 

Environmental issues associated with the subsurface release of petroleum hydrocarbons and other organics fall into four areas (1) vapors (Figure 1.5), (2) impacted soils, (3) the presence of nonaqueous phase liquids (NAPLs), and (4) dissolved constituents (i.e., benzene, toluene, ethylbenzene, and xylenes (BTEX), and other components) in groundwater. 

Hunt, J. R., Sitar, N., and Udell, J., 1988, Nonaqueous Phase Liquid Transport and Cleanup, Part 1. Analysis of Mechanisms Water Resources Research., Vol. 24, No. 8, pp. 1247-1258. 

Panday, S., Forsyth, R A., Falta, R. W., Wu, Y., and Huyakorn, P. S., 1995, Considerations for Robust Compositional Simulations of Subsurface Nonaqueous Phase Liquid Contamination and Remediation Water Resources Research, Vol. 31, No. 5, pp. 1273-1289. 

Adams, M. L., Sinclair, N., and Fox, T., 1998, 3-D Seismic Reflection Surveys for Direct Detection of DNAPL In Nonaqueous-Phase Liquids, Remediation of Chlorinated and Recalcitrant Compounds (edited by G. B. Wickramanayake and E. Hinchee), Battelle Press, Columbus, OH, pp. 155-160. 

---