• Economic and Environmental Geology
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• v.44 no.3
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• pp.203-215
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• 2011

Geochemical and mineralogical properties of a contamited soil should be taken into account to decide a remediation strategy for a given contaminant because development and optimization of soil remedial technologies are based on geochemical and mineralogical separation techniques. The objective of this study was to investigate the geochemical and mineralogical characteristics of arsenic-contaminated soils. The arsenic-contaminated soil samples were obtained from Chonam gold mine, Gwangyang, Chonnam, Particle size analysis, sequential extraction, and mineralogical analyses were used to characterize geochemical and mineralogical characteristics of the As-contaminated soils. Particle size analyses of the As-contaminated soils showed the soils contained 17-36% sand, 25-54% silt, 9-28% clay and the soil texture were sandy loam, loam, and silt loam. The soil pH ranged from 4.5 to 6.6. The amount of arsenic concentrations from the sequential soil leaching is mainly associated with iron oxides (1 to 75%) and residuals (12 to 91%). Major minerals of sand and silt fractions in the soils were feldspar, kaolinite, mica, and quartz and minor mineral of which is an iron oxide. Major minerals of clay fraction were composed of illite, kaolinite, quartz, and vermiculite. And minor minerals are iron oxide and rutile. The geochemical and mineralogical analyses indicated the arsenic is adsorbed or coprecipitated with iron oxides or phyllosilicate minerals. The results may provide understanding of geochemical and mineralogical characteristics for the site remediation of arsenic-contaminated soils.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.55-62
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• 1999

The solvent flushing apparatus for soil remediation was designed. After the soil around nuclear facilities was sampled and compulsorily contaminated by Co, the characteristics remediated by solvent flushing were analyzed. Meanwhile, the nonequilibrium sorption code was developed for modelling of the soil remediation by solvent flushing, input parameters needed for modelling were measured by laboratory experiment. Experimental results are as follows : The soil around nuclear facilities belongs to Silt Loam including a lot of silt and sand. When water was used as a solvent, the higher was the hydraulic conductivity. the higher the efficiency of soil remediation was. The values calculated by the nonequilibrium sorption code agreed with experimental values more exactly than the values calculated by the equilibrium sorption code. When EDTA solution was used as a solvent. the soil remediation efficiency by EDTA solution showed higher than that by water.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1076-1086
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• 2010

Soil remediation technologies were experimented to evaluate whether the technologies could be used to apply remediation of contaminated marine sediment. In this research, marine sediments were sampled at "Ulsan" and "Jinhae" where remediation projects are considered, and then the possibility of heavy metal removal was evaluated throughout the technologies. Heavy metal concentration of silt and clay fraction was higher than that of sand fraction at "Ulsan". Heavy metal removal of the silt and clay fraction was arsenic (As) 81.5%, mercury (Hg) 93.8% by particle separation, cadmium (Cd) 72.2%, mercury (Hg) 93.8% by soil washing technology, cadmium (Cd) 70.8%, lead (Pb) 65.6% by another soil washing technology. Based on experimental results, tested particle separation and soil washing technologies could be used to remove heavy metals of sand fraction and silt and clay fraction. Heavy metal removal by soil washing technology which was composed of separation, washing and physical or chemical reaction by additives such as acid, organic solvents was more effective comparing to that of particle separation. Since heavy metal concentration of all treated samples was suitable for national soil standards, all the tested technologies were could be used not only to remove heavy metals of marine contaminated sediment but also to reuse treated samples in land.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1121-1129
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• 2003

We report the distributions of Sb and As in the surface sediment of the Yellow Sea and the coastal areas of Korea. The mean concentrations of Sb and As range from 0.68 ppm to 1.01 ppm and from 7.4 ppm to 15.8 ppm, respectively, and show relatively the high concentrations at the coast of Weolseong in the East Sea for Sb and at the coast of Gadeok Island in the South Sea far As. This may be due to the anthropogenic input of these elements via river and atmosphere from industry complex and agriculture regions around the study areas. Because of the difference of clay to silt proportion, the correlation between silt plus clay contents and Sb, As in the coastal surface sediment of Korea is not shown, the concentrations of Sb and As vary widely for the sample in which the silt plus clay contents are the same. Therefore, we suggest that the distribution patterns of Sb and As in surface sediment of the Yellow Sea and the coastal areas of Korea are mainly controlled by the anthropogenic inputs and the sediment characteristics. On the other hand, the Sb concentrations are lower than those of the lowest effect level which is the standard of judgment for contamination, while the As concentrations are higher than those of the lowest effect level. This implies that the surface sediments of the Yellow Sea and the coastal areas of Korea are considerably contaminated for As.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.43-51
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• 2018

In order to systematically and scientifically manage the organic and heavy metals against sediment at Daecheon Port, this study conducted particle composition, organic materials and heavy metals irradiation studies of sediments. Analysis of the grain size composition of sediments in the target study area showed the distribution characteristics of the mix of sand, silt and clay. That is, Station C (Stn. C) showed superior by fine-grained sediment, Station A and B (Stn. A and B) showed superior by coarse-grained sediment. The organic matter(COD, TOC, and IL) of Stn. C was appeared to be heavily polluted more than Stn. A and B. These data for the spatial properties in sediment showed that organic matter was related positively to the sediment silt-clay content. Also, in the case of heavy metals contamination in surface sediments, Stn. C was higher than Stn. A and B. Particularly, at the Stn. C, high organic matter concentration and C/N ratio value( >10) indicated that the sediment was composed highly of land-derived organic matter. From these results, it considered that the correlation analysis among to silt-clay, organic matter and heavy metal was found to have a good interrelationship.

• Journal of environmental and Sanitary engineering
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• v.11 no.2
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• pp.65-73
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• 1996

The objective of this study is to investigate the removal efficiency of volitile organic compounds in soil, and the mechanism of desorption by bench scale microwave heating, Silt soil used for experiment and was impregnated with toluene, tetrachloroethylene, o-xylene and p-dichlorobenzene and the microwave treatment was conducted in a modified domestic microwave oven : 2450MHz, 700W. According to the results of the research the removal efficiency was improved with increasing water contents and the soil temperature appeared to plateau period extending to 2-3minutes corresponds to the temperature a which steam distillation was expected. The value of removal rate constant (k) were calculated on dry and moisty silt soil, respectively, which showed linear with increasing microwave heating time. Therefore, addition of a certain amount of water to the contaminated soil can efficiently enhance the ability of the soil to absorb microwave energy and promote the evaporation of the volitile contaminants.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.418-421
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• 2003

Surfactant enhanced in-situ soil flushing was peformed to remediate the soil and groundwater at an oil contaminated site, and the effluent solution was treated by the chemical treatment process including DAF(Dissolved Air Flotation). A section from the contaminated site(4.5m$\times$4.5m$\times$6.0m) was selected for the research, which was composed of heterogeneous sandy and silt-sandy soils with average Hydraulic conductivity of 2.0$\times$10$^{-4}$ cm/sec. Two percent of sorbitan monooleate(POE 20) and 0.07% of iso-prophyl alcohol were mixed for the surfactant solution and 3 pore volumes of surfactant solution were injected to remove oil from the contaminant section. Four injection wells and two extraction wells were built in the section to flush surfactant solution. Water samples taken from extraction wells and the storage tank were analyzed by GC(gas-chromatography) for TPH concentration with different time. Five pore volumes of solution were extracted while TPH concentration in soil and groundwater at the section were below the Waste Water Discharge Limit(WWDL). Total 18.5kg of oil (TPH) was removed from the section. The concentration of heavy metals in the effluent solution also increased with the increase of TPH concentration, suggesting that the surfactant enhanced in-situ flushing be available to remove not only oil but heavy metals from contaminated sites. Results suggest that in-situ soil flushing and chemical treatment process including DAF could be a successful process to remediate contaminated sites distributed in Korea.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.53-63
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• 2010

Pneumatic fracturing is an emerging tool to enhance the remediation efficiency of contaminated unsaturated zones by injecting high pressure air and inducing artificial fracture networks. Pneumatic fracturing is reported to be well suited for the cases where the contaminated unsaturated zone thickness is less than 5 m as many contaminated domestic sites in Korea. Nevertheless, there have been almost no studies carried out on the site-specific efficiency and the optimized design of pneumatic fracturing considering the unsaturated zone characteristics of Korea. In this study, we employ numerical simulations to compare the efficiency of pneumatic fracturing on the aspect of the site remediation and the porosity improvement at several hypothetic unsaturated zones composed of four typical soil types. According to the simulation results, it is found that the zone with fine grains soil such as clay and silt shows better efficiency than the zone composed of coarse grains in terms of air flow and porosity enhancements. The results imply that pneumatic fracturing may improve the efficiency of site reclamation by jointly or independently applied to the many contaminated sites in Korea.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.2
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• pp.132-139
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• 2002

This study was carried out to investigate the effects of aging and soil texture on composting of diesel-contaminated soil. The soils used for this study were silt loam and sand. Target contaminant, diesel oil, was spiked at 10,000mgTPH/kg of dry soil. Aging times of diesel-contaminated soils were 15days and 60days, respectively. Fresh diesel-contaminated soil was also investigated. Moisture content was controlled to 70% of soil field capacity. Mix ratio of soil to sludge was 1:0.3 as wet weight basis. Temperature was maintained at $20^{\circ}C$ Volatilization loss of TPH was below 2% of initial concentration. n-Alkanes lost by volatilization were mainly by the compounds of C10 to C17. Diesel in contaminated soil was mainly removed by biodegradation mechanism. First order degradation rate constant of TPH in sandy soil was ranged from 0.081 to 0.094/day, which is higher than that in silt loam(0.056-0.061/day). From fresh to 60day-aged soils, there was little difference of TPH biodegradation rate between the soils. Carbon recovery ranged from 0.61 to 0.89. TPH degradation rate was highly correlated with $CO_2$ production rate.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.783-789
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• 2003

This study was conducted to reuse the rice straw ash as washing agent for oil contaminated soils. The results are summarized as follows. The physical characteristics of rice straw before and after burning were as follows ; In case of burning rice straw 1g, the rice straw ash was generated 0.14g and pH was changed neutrality into alkali(pH 10.9) and specific surface area was increased to five times and particle distribution was corresponded to fine silt.(under 0.05mm) The physical characteristics of rice straw ash were Carbon 10.9%, Hydrogen 1.5%, Oxygen 23.4%, Nitrogen 5.2%, Sulfate 1.2% and chemical characteristics were Si 189.2ppm, Ca 10.2ppm, Mg 4.7ppm. Oil cleanup ratio by pH variation were about 40∼50% of initial concentration of oil by pH 10∼11. As the result of cleanup comparative experiment, the rice straw ash was about 20∼30%, the tritonX-100 about 40∼50% of washing efficiency, and then in the future it will be possibility of substitute washing agent.