The use of time domain reflectometry (TDR) to determine and monitor non-aqueous phase liquids (NAPLS) in soils
This research deals with the potential use(s) of Time Domain Reflectometry (TDR) to determine and monitor Non-Aqueous Phase Liquids (NAPLs) in soils. TDR is an established method to determine water content and electrical conductivity of soils. Other applications include solute transport and NAPLs migration in subsurface. A two phase experiment was implemented to study NAPLs in soils. In the first phase, three NAPLs (gasoline, diesel and tetrachloroethylene) and five soils (fine sand, coarse sand, and 10%, 30%, and 50% silty sand) were used. The NAPL was added to the soil which contained a specific water content, until it was saturated, and the dielectric constant was monitored after each addition. In the second phase, the NAPL's transport in the subsurface was monitored in a polyethylene cell. Two NAPLs (diesel and tetrachloroethylene) and two soils (fine and coarse sand) were used in this phase. Three TDR probes were inserted into the soil, spaced 12.7 cm apart. The NAPLs migration was monitored by the reduction of the dielectric constant determined by TDR. The volumetric fraction of water displaced by the NAPL was estimated. The results of phase I revealed that the NAPLs caused the dielectric constant to increase when the soil was not saturated and to decrease when it was at saturation. In phase II, the dielectric constant was reduced as a result of the transport of the NAPL in the soil and replacing the water. The dielectric constant, however, remained unchanged under the water table in the LNAPL experiments.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:time domain reflectometry non aqueous phase liquids
Date of Publication:01/01/1997