• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.124-127
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• 2003

Laboratory scale experiments on in-situ ozonation were carried out to delineate the effects of liquid phases, such as soil water and nonaqeous phase liquid (NAPL) on the transport of gaseous ozone in unsaturated soil. Soil water enhanced the transport of ozone due to water film effect, which prevent direct reaction between soil particles and gaseous ozone, and increased water content reduced the breakthrough time of ozone because of increased average linear velocity of ozone and decreased air-water interface area. Diesel fuel as NAPL also played a similar role with water film, so the breakthrough time of ozone in diesel-contaminated soil was significantly reduced compared with uncontaminated soil. However, ozone breakthrough time was retarded with increased diesel concentration, because of high reactivity of diesel fuel with ozone. In multiphase liquid system of unsaturated soil, the ozone transport was mainly Influenced by nonwetting fluid, diesel fuel in this study.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.151-156
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• 1995

Single-drop splash/detachment studies and multiple-drop splash/detachment experiments were carried out to measure detachment by single and multiple drops. A raindrop tower 7.0 m in height was used to study soil splash by single drop raindrop impact over time on repacked soil samples in containers 76.2 mm in diameter. The waterdrop diameter and kinetic energy were 4.1 mm and $1.22{\times}10^{-3}$ J $drop^{-1}$, respectively. The samples consisted of five agricultural topsoils sieved to <2 mm, varying from sandy loam to clay loam in texture. The average weight of splashed soil particles after 75 drops did not show any significant difference between the five soils. The average weight of particles splashed by the first 15 drops showed that the sandy Pelham soil splashed to a greater degree than the others, and was therefore more detachable (p=0.05) than the other soils. The average weight of particles splashed by the last 15 drops also showed that the Pelham soil was the most detachable, with Cecil, Appling, Dyke, and Worsham soils being progressively less detachable. The effect of multiple drops on detachment was studied under a nozzle-type rainfall simulator at 74.9 mm $h^{-1}$ intensity for 85 min using the same soils as the single drop experiments. The total soil splash value for 85 min on Appling, Cecil, Dyke, Pelham, and Worsham soils were 6121, 6206, 4183, 5160, and 3247 g $m^{-2}$, respectively. There were no obvious relationships between soil loss measured from the different experiments.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.6
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• pp.823-832
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• 2004

Atmospheric aerosol particles collected in Seoul on four single days, each in every seasons of 2001, were characterized and classified on the basis of their chemical species using low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA). Low-Z particle EPMA technique can analyze both the size and the chemical species of individual aerosol particles of micrometer size and provide detailed information on the size distribution of each chemical species. The major chemical species observed in Seoul aerosol were aluminosilicate, silicon dioxide, calcium carbonate, organic, carbon-rich, marine originated, and ammonium sulfate particles, etc. The soil originated species, such as aluminosilicate, silicon dioxide, and calcium carbonate were the most popular in the coarse fraction, meanwhile, carbonaceous and ammonium sulfate were the dominant species found in the fine fraction. Marine originated species such as sodium nitrate was frequently encountered, up to 30% of the analyzed aerosol particles.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.2
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• pp.60-63
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• 2004

The electrical breakdown characteristics of different types of soil samples have been measured. It is shown that the threshold soil breakdown strength is affected by many factors, such as types of soil, grain size, and soil compaction. The breakdown process in the test soil samples appears to be due to air ionization in the voids between the soil particles. The results have been compared with the relevant experimental results of other researchers.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.381-388
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• 1999

Several large scale reclamation projects are being underway along the coastal line in Korea. Therefore the large quantity of economical backfill material is necessary to cope with the shortage of dredged soil. In this study, the amount of volume reduction of dredged soil from detention basin was evaluated based on the laboratory tests. The percentage of soil particles in dredged organic soil is about 12.5∼21.9% by weight. The content of heavy metal and environmental effect for dredged soil itself and solidified dredged soil were analysed and the results are far below than those of environmental requirement.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.140-143
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• 2001

The packed column experiments were conducted with commercial Jumunjin sand(SOM content : 0.01 %) and a field soil(SOM content : 0.08 %) in order to understand the effects of water content and soil organic matter(SOM) on the transport of gaseous ozone in unsaturated soil contaminated with phenanthrene. Water content and SOM content were artificially controlled. As water content increased, earlier breakthrough was observed in the beginning of BTC of ozone, because direct contact of gaseous ozone with SOM and phenanthrene was prevented by water film formed between soil particles and gaseous ozone. The total removal of phenanthrene in Jumunjin sand was not affected by water content which was more than 99% at different water content(4.4, 8, 17.3%). However, the removal in field soil at water content 6.5 % and 20 % was 98% and 80 %.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.559-562
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• 2001

There are many engineering applications that demand settling acceleration and volume reduction of fine solid suspensions. It is a matter to Improve the dredged soil thickening as well as the dewatering characteristic, because settling acceleration of dredged soil decreases the scale of industrial process and volume reduction of dredged soil decreases environmetal challenge to the disposal sites. Direct electric current induces the movement of fine solid particles suspended in water. Upon formation of a soil structure, the current further induces the movement of water and contaminant in the soil skeleton. Theses phenomena are known as electrokinetics. This study investigates the viability, of using the technique of electrokinetic dewatering to river dredged soil for settling acceleration and volume reduction. The aspect, such as sedimentation velocity, final volume and current variation are discussed.

• Journal of Soil and Groundwater Environment
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• v.12 no.3
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• pp.44-52
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• 2007

Contaminated sediments more than 30 million/$m^3$ is generated from dredging work for harbours and coastal maintenance in Korea. Approximately 300 million/$m^3$ of sediments is dredged to deepen harbours and shipping lanes in US and of which $3{\sim}12million/m^3$ is highly contaminated. Although much is known about technologies for the remediation of heavy metal contaminated soil, much less is known about the treatment of contaminated sediment. In general, negatively charged fine particles will migrate towards positively charged system of electrodes under the influence of electrophoresis. However, the electrically induced migration of colloidal particles contaminated with heavy metals may be hindered by the positively charged heavy metal contaminants adsorbed onto the soil surfaces depending on the contamination level. This paper demonstrates settling behaviour of clayey soil by comparison with electrophoretic particle movement under the effects of heavy metal contamination, applied electric field strength, and its polarity changed by the electrode configuration.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.73-81
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• 1997

Retention ponds have been dug along some of the motorways to control water flow during rainstorms and to minmize environmental pollution. A retention pond located at Les Ardilleres about 20km South of Orleans along the A-71 motorway has been selected to evaluate the effectiveness of such a pond as a trap for heavy metals. Based on the "index of geoaccumulation" and the "enrichment factor" normalized to Fe introduced by Muller in 1979 and by Helz in 1976, respectively, the degree of contamination by heavy metals for the roadside soil and the settling particles was evaluated. As expected, the contamination was very severe in the roadside soil, while it was not so great in the settling particles. Using these methods, cadmium anomaly was traced in the settling particles of the retention pond, their occurrence being attributed partly to natural and partly to anthropogenic pollution. The estimated input of heavy metals associated with settling particles to the pond was 0.9 g/day Pb, 2.1 g/day Zn and 6mg/day Cd. A tentative mass balance of Pb and Zn originated by motor vehicles suggested that only 5 to l1% of heavy metals deposited on the surface of the motorway is carried to the retention pond by runoff water ; suggestions are made to improve their efficiency.ve their efficiency.

• Clean Technology
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• v.29 no.2
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• pp.118-125
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• 2023

Once a site is contaminated with polychlorinated biphenyls (PCBs), serious environmental and human health risks are inevitable. Therefore, innovative but economical in situ remediation technologies must be immediately applied to the contaminated site. Recently, nanoscale zero-valent iron (nano-ZVI) particles have successfully been applied for the dechlorination of various chlorinated organic compounds like TCE, PCE and DDT, and they are considered to be environmentally safe due to the high abundance of iron in the earth's crust. Nano-ZVIs are much more reactive than granular ones, but tend to agglomerate due to their high surface energy and magnetic properties. In order to prevent them from being agglomerated toward larger particles, TiO₂ was used as a support to immobilize the nano-ZVI particles as much as possible. 10wt% ZVI/TiO₂ was prepared by adding NaBH₄ slowly into an FeSO₄/TiO₂ aqueous slurry. In spite of their non-uniformity in size, the nano-ZVI particles were quite successfully dispersed onto the exterior surface of a non-porous TiO₂ powder. The ZVI/TiO₂ was then employed to degrade Aroclor 1242, a kind of PCBs standard, in spiked soil, and its reactivity towards the degradation of Aroclor 1242 was investigated. The fabricated ZVI/TiO₂ degraded Aroclor 1242 in soil quite effectively, but the creation of remaining dechlorinated compounds, possibly high molecular weight hydrocarbons, in the soil was unavoidable.