• Journal of Korea Soil Environment Society
• /
• v.2 no.1
• /
• pp.51-61
• /
• 1997

The objective of this study is to evaluate the feasibility of Pumping-and-Treatment system (PTS) for remediation of the saturated zones contaminated with NAPLs. A simulation is carried out for the removal of DNAPLs (denser-than-water non-aqueous phase liquids) and LNAPLS (lighter-than-water non-aqueous phase liquids) distributing at and below the water table. In the study, LNAPL and DNAPL are assumed to be n-hexane and 1,1-dichloroacetone, respectively. The model system studied consists of four heterogeneous soil layers with different permeabilities. Groundwater flows through the bottom layer and a pumping well is located under the initial water table. The time-driven deformation of the water table and removal efficiency of contaminants are estimated after vacuum application to the inlet of the well. In the calculation, FVM (Finite Volumetric Method) with SIMPLEC algorithm is applied. Results show that removal efficiencies of both DNAPL and LNAPL are negligible for the first 5 days after the PTS operation. However, when the cone-shape water table is formed around the inlet of the pumping well, the rapid removal rate is obtained since NAPLs migrate rapidly through the curvature of the water table. The removal efficiency of DNAPL is estimated to be higher than that of LNAPL due to the gravity. The results also show that the fluctuation or cone-shaped depression of the water table enhances the removal efficiency of NAPLs in saturated zones. The simulation results could provide a basis of the PTS design for the removal of NAPLs in saturated zones.

• Journal of Soil and Groundwater Environment
• /
• v.11 no.6
• /
• pp.28-34
• /
• 2006

Laboratory column tests using $Cl^-$ tracer were conducted to study the correlation of soil particle distribution and hydrodynamic dispersion mechanism with three kinds of ununiformed soil samples, in which the ratio of gravel and sand versus silt and clay is 24.5 for S-1 soil, 4.48 for S-2 soil, and 0.4 for S-3 soil. Chloride breakthrough curves with time were fitted with gaussian functions. The relative concentrations of chloride were converged to 1.0 after 0.7 hours for S-1, 6.3 hours for S-2, and 389 hours for S-3. Average linear velocity, longitudinal dispersion coefficient, and longitudinal dispersivity were calculated by chloride breakthrough curves. Longitudinal dispersion coefficients were $1.20{\times}10^{-4}\;m^2/sec$ for S-1, $8.87{\times}10^{-7}\;m^2/sec$ for S-2, and $1.94{\times}10^{-9}\;m^2/sec$ for S-3. Peclet numbers calculated by the molecular diffusion coefficient of chloride and the mean grain diameters of soils were $2.59{\times}10^2$ for S-1, $6.27{\times}10^0$ for S-2, and $1.35{\times}10^{-4}$ for S-3. Mechanical dispersion was dominant for the hydrodynamic dispersion mechanism of S-1. Both mechanical dispersion and molecular diffusion were dominant for the hydrodynamic dispersion mechanism of S-2, but mechanical dispersion was ascendant over molecular diffusion. Hydrodynamic dispersion in S-3 was occurred mainly by molecular diffusion. When plotting three soils on the graph of $D_L/D_m$ versus Peclet number produced by Bijeljic and Blunt (2006), the values of $D_L/D_m$ for S-1 and S-2 were more than 2.0 order compared to their graph. S-3 was not plotted on their graph because the Peclet number was as small as $1.35{\times}10^{-4}$.

• Korean Journal of Soil Science and Fertilizer
• /
• v.29 no.2
• /
• pp.86-91
• /
• 1996

Water vapor adsorption isotherms were measured for samples of the A horizons of five typical Korean soils. The experimental data were fitted to the BET and Aranovich adsorption equations. The adsorption isotherms studied followed the BET equation for the relative water vapor pressures in 0.03-0.33 range and the Aranovich equation in 0.03-0.6 range. The calculated surface areas were higher for Aranovich than for BET and opposite relations were found for adsorption energies. For the description of the water adsorption on soils, the use of the Aranovich theory is recommended.

• Journal of Conservation Science
• /
• v.25 no.2
• /
• pp.155-160
• /
• 2009

This study is designed to optimize the method of using SE-101 for strengthening the durability and the stabilization of moving historical site. The permeability and the shear strength of The epoxy SE-101 with low viscosity were measured on different particle sizes and moisture content of soil. Like it can be expected from the data of viscosity, as the soil particle size was increased, the permeability was also increased, while the shear strength was decreased. And especially, it is noted that the deviation of permeability can be more extreme according to the different hardening speed of macromolecule and mineral additives. As the rate of moisture content in soil sample is increased, the deviation between permeability and shear strength is also increased. Even though among the same soil sample, some parts of it can be weaker than others, which cause the breakages of epoxy products. Thus, it is necessary that the soil should be dried over 50% of permeation depth of SE-101 before use.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.11 no.4
• /
• pp.90-96
• /
• 2003

This study was performed to evaluate effect of extraction mode on SVE efficiency for fuel-contaminated soil. A gas station was selected for this study. As a result of pressure test in well head, soil texture of contaminated site under the gas station was very different from site to site. SVE system was operated in intermittent mode (1hr extraction / 3hr rest) or continuous mode. Capacity of air blower was $1m^3/min$. Extration mode test was conducted in two severe contaminated sites. In both two sites, cumulative TPHgas mass of intermittent extraction mode was higher than that of continuous mode. Considering long term operation of SVE in a field, in general, it was thought that intermittent extraction mode was effective in view of vaporized TPHgas mass and electrical cost.

• Korean Journal of Ecology and Environment
• /
• v.46 no.2
• /
• pp.310-318
• /
• 2013

In territorial ecosystem, soil has stored considerable amount of carbon, and it is vulnerable to weakness release much of the carbon to atmosphere. In this study, we have been effort realization and discussion to the error between inter-instruments and measurement methods, time and special variations, gap filling and separation from each source included in soil respiration, used to collect soil respiration data in various ecosystems in Korea. In conclusion, it have to collect calibration data throughout comparison test between methods and instruments because accumulated data from past and accumulating data in present did not calibrated. In predicting change of soil carbon dynamic using the model method, it needs important data such as longterm and short-term data, artificial handling data of major factor, data from various ecosystem, soil texture, soil depth etc. In company with, we should collect highly qualified data through deep consideration of present problems.

• Journal of Soil and Groundwater Environment
• /
• v.14 no.1
• /
• pp.51-60
• /
• 2009

A series of experiments was performed to develop an optimized analytical procedure for the analysis of explosives in soil by HPLC with soil samples collected at two live-fire military shooting ranges. The minimum amount of soil to be collected, Wmin, for the analysis of explosive compounds was 125g, based on the segregation and homogeneity constants that account for soil heterogeneity and non-homogeneous distribution of target explosive compounds. The optimization of extraction and HPLC analytical conditions were also studied based on analytes CV values. The most effective soil/ extractant ratio was estimated to be 10g-pretreated soil/20 mL acetonitrile as extractant. The optimized HPLC elution conditions for the separation of US EPA designated 14 explosive compounds, were column temperature 30${\circ}C$, eluents ratio of isopropanol: acetonitrile: water = 18 : 12: 70, and flow rate of 0.8 mUmin at 230 nm. However, UV wavelength 254 nm was better for the analysis of NB, 2,4-DNT, 2NT, 4NT, and 3NT.

• Korean Journal of Soil Science and Fertilizer
• /
• v.11 no.2
• /
• pp.61-66
• /
• 1979

This experiment was conducted to find out the simple and economical method to improve physical properties of the soil that was very poor for the establishment of orchard. Jeonnam clay loam soils distributed mainly on rolling and hill side slope, were treated with the explosion of two kinds of dynamite at the depth of 1 m. The change of physical properties was investigated vertically and horizontally after soil profile had settled to some extent. The results were summarized as : 1. The original soil was very high in bulk density and soil hardness. Total porosity and aeration porosities were lower than critical level providing root elongation. It was more apparent in the subsoil than in the surface soil. 2. It was recognized that soil mass destruction and cracking by dynamite explosion decreased soil bulk density and soil hardness and increased porosity, especially non-capillary pores. 3. Effective radius of the improved physical properties by explosion with two dynamites was 100cm at 60cm depth and 30cm at 80cm depth. But with the use of three dynamites it was 100cm at 80cm depth. 4. It was thought that soil mass destruction and cracking caused by explosion was uneven in the two dynamites, and three dynamites was more effective to improve physical properties evenly. 5. With the use of two dynamites, Ammonium explosive was superior to gelatin dynamite.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.11 no.4
• /
• pp.151-161
• /
• 2009

Configuration of soil hydraulic property is an essential component to understand the hydrological processes at the hillslope scale. In this study, we investigated temporal variations in pore development and soil hydraulic properties during the period from March to October in 2008. Characteristics for macropore flow and hydraulic conductivity were measured at two hillslopes: one is the hillslope located at the Buprunsa in Sulmachun watershed, and the other is the hillslope located in Gwangneung Research Forest. Vertical fluxes through macropore were measured using a tension infiltrometer at the depth of surface. The saturated hydraulic conductivities in March, June, July and September were relatively high compared to those in May and October. Temporal variations in several soil hydraulic features could be explained by the differences in vegetation activity and soil moisture content determined by antecedent precipitation. Particularly, the features of macropores had a substantial impact on hydraulic conductivity in the forest hillslope. The temporal nonuniformity of the soil hydraulic properties observed in this study manifests the dynamic features of hydrological processes in the hillslope scale and the experimental results will be useful to understand the internal hydrological processes in the mountainous hillslope.

• Horticultural Science & Technology
• /
• v.19 no.4
• /
• pp.511-514
• /
• 2001

Pelleting the seeds often reduces seed germinability. In an effort to alleviate this problem, the seeds of four carrot cultivars were, before pelleting, either solid-matrix primed (SMP) with Micro Cel-E or osmotically-primed with polyehtylene glycol 8000. Some batches were imbibed in 100-ppm $GA_3$ solution. In laboratory tests, pretreatment of the seeds increased the precentages of germination by as much as 50% of the controls, indicating the increase of the germination speed by 1.9 to 4.6 days as determined by the $T_{50}$ values. In field tests conducted in the year of 2000 and 2001, however, effects of SMP were not observed. There was no significant difference between the SMP seeds and the controls of the percentages and $T_{50}$ values. The emergence of the seedling in the field was affected greatly by soil water concentration.