Estimation of LNAPL saturation in fine sand using time-domain reflectometry

• Recently, substantial progress has been made in detection and observation of non-aqueous phase liquids (NAPLs) in the subsurface using different experimental techniques. However, there is still a lack of appropriate direct methods to measure the saturation of NAPL theta(NAPL)). This paper provides a guide for estimating theta(NAPL) and water content (theta(a)) in unsaturated and saturated sand based on direct measurements of soil dielectric constant (K-a) and electrical conductivity (sigma(a)) using time domain reflectometry (TDR). The results show that the previously used dielectric mixing model fails to predict, theta(NAPL) in the case of a four-phase system. A new methodology is suggested and exemplified by showing that the measured K-a gives accurate estimation of theta(NAPL) for a three-phase system while in a four-phase system, both sigma(a) and K-a need to be measured. The results show that using the suggested methodology, accurate predictions of theta(w) (R-2 = 0.9998) and theta(NAPL) lower than 0.20 m(3) m(-3) (average R-2 = 0.9756) are possible.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Vattenteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Water Engineering (hsv//eng)

Keyword

time domain

LNAPL

dielectric constant

electric conductivity

water content

reflectometry

Publication and Content Type

art (subject category)

ref (subject category)