• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.9-19
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• 2021

This study evaluated the feasibility of combined use of physical separation and soil washing to remediate heavy metals (Pb and Cu) contaminated soil in a military shooting range. The soils were classified into two types based on the level of heavy metal concentrations: a higher contaminated soil (HCS) with Pb and Cu concentrations of 6,243 mg/kg and 407 mg/kg, respectively, and a lower contaminated soil (LCS) with their concentrations of 1,658 mg/kg and 232 mg/kg. Pb level in both soils exceeded the regulatory limit (700 mg/kg), and its concentration generally increased with decreasing soil particle size. However, in some cases, Pb concentrations increased with increasing soil particle size, presumably due to the presence of residues of bullets in the soil matrix. As a pretreatment step, a shaking table was used for physical separation of soil to remove bullet residues while fractionating the contaminated soils into different sizes. The most effective separation and fractionation were achieved at vibration velocity of 296 rpm/min, the table slope of 7.0°, and the separating water flow rate of 23 L/min. The efficiency of ensuing soil washing process for LCS was maximized by using 0.5% HCl with the soil:washing solution mixing ratio of 1:3 for 1 hr treatment. On the contrary, HCS was most effectively remediated by using 1.0% HCl with the same soil:solution mixing ratio for 3 hr. This work demonstrated that the combined use of physical separation and soil washing could be a viable option to remediate soils highly contaminated with heavy metals.

• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.36-50
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• 2023

Soil health can deteriorate through both contamination and remediation. Accordingly, revitalization processes are needed to reuse or recycle the remediated soil. The study was conducted to assess the changes in soil health parameters of heavy metals-contaminated soil during soil washing process. In addition, unit processes were proposed to improve the quality of the remediated soil relevant to its reclamation purposes, such as agricultural and forest lands. A total of 21 indicators were used to determine whether the soil health was degraded or recovered. The performance of 6 amendments in improving soil health was quantitatively evaluated according to their dosage and application duration. Finally, the experimental results were assessed by simple regression analyses to determine the statistical significance and relative performance of each amendment. The results indicated that 18 health indicators out of 21 deteriorated through the soil washing process. Based on the results, it is recommended that several effective amendments be complementarily combined and applied in real applications because use of single amendment does not likely improve the quality of remediated soils.

• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.59-67
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• 2023

This review examined the current administrative policies and guidelines for management of reclaimed soils after remediation processes and proposed practical strategies to improve the potential value of the remediated soil as a resource. Three management practices are proposed to facilitate more efficient recycling of remediated soil; obligatory use, quality certification, and tracking of the remediated soils. If properly implemented in utilization of remediated soil, these strategies could contribute to enhancing public safety by assuring soil quality. Such administrative tools, for both suppliers and demanders, are expected to mitigate potential risks associated with the transactions of remediated soil. To enhance the quality assurance process, a soil quality certification combined with the soil health assessment index was proposed. The systematic integration of the suggested practices with soil health assessment can allow to produce optimal results, encompassing affordability, efficiency, and accessibility, which helps establishing more robust 'Remediated Soil Recycling Management System (RSRMS)'. Subsequent researches should be conducted to develop more effective policies that incorporate soil health assessment tools. The proposed management practices for remediated soil, coupled with soil health assessment, can be a pioneering effort to achieve such goals. By fostering an environmentally friendly policies, the sustainable utilization of remediated soil can be attained. Overall, the proposed strategies can provide a sound framework for responsible and sustainable soil management practices.

• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.87-94
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• 2009

Surfactant-enhanced air sparging (SEAS) was developed to suppress the surface tension of groundwater prior to air sparging resulting in higher air saturation and larger contact area between NAPL and gas during air sparging. Larger contacting interface between NAPL and gas means faster mass transfer of contaminants from NAPL to gas phase. This new technique, however, is limited to relatively volatile contaminants because vaporization is its basic mechanism of mass transfer. In this study, SEAS was tested at an elevated temperature for a semi-volatile n-decane, which is expected not to be a good candidate of SEAS application due to its low vapor pressure at ambient temperature. Three sparging experiments were conducted using 1-dimensional column (5 cm id, 80 cm length) packed with sand; (1) ambient temperature ($23^{\circ}C$), column saturated with distilled water, (2) SEAS at ambient temperature ($23^{\circ}C$), for n-decane contaminated sand, (3) SEAS at elevated temperature ($73^{\circ}C$), for n-decane contaminated sand. Higher air saturation was achieved by SEAS compared to that by air sparging without surfactant application. The n-decane removal efficiency of SEAS at elevated temperature was significantly higher(> 10 times) than that of ambient SEAS. The n-decane concentrations in the gas effluent from column during SEAS at $73^{\circ}C$ are found to be 10 times of those measured at ambient temperature. Thus, SEAS technique can be applied for removal of semi-volatile contaminants provided that an appropriate technique for elevating aquifer temperature is available.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.52-61
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• 2004

In order to remediate soils contaminated with oxyanionic As and cationic Zn and Ni through the pilot-scale acid washing, the effectiveness of acid washing and the properties of contaminated soils, fine soil particle and dissolved contaminants were evaluated. $H_{2}SO_4\;and\;H_{3}PO_4$ washing at pH $2{\sim}3$ enhanced the removal of As by the presence of competitive oxyanions and HCl washing effectively removed simultaneously As, Zn and Ni. The effectiveness of soil washing was little enhanced above the critical reaction time, and the carbonate, Fe/Mn oxide and organic/sulfides associated fraction were dominantly removed. The washing of coarse soil particles was highly efficient, but that of fine soil particles($<74{\mu}m$) was recalcitrant due to the enrichment with contaminants. Moreover, the physical separation of fine particles($<149{\mu}m$) enhanced the overall efficiency of soil washing. Therefore, both chemical extraction and separation of fine soil particles showed the high effectiveness of soil washing in the intersection point to minimize the amount of fine soil particles and to maximize the chemical extraction of contaminants.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.343-352
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• 2016

Effects of grinding time and chemicals dosage in arsenic removal from contaminated paddy soil in China were investigated using lab scale attrition and froth flotation combining process. Arsenic concentration in the field soil was 76.51 mg/kg, exceeding Korean and Chinese standards, and predominant arsenic compounds fraction in sequential extraction was "residual" (over 80%). After wet sieving, soil with >2 mm and < 0.038 mm showed concentration lower than 'Warning Level' in Korea. Soil with 0.038-0.075 mm, showing the highest concentration, was discarded since it occupied minor weight fraction (10.1%). Thus soil between 0.075 and 2 mm was only used in the combining process. The highest Arsenic concentration in progeny fragments smaller than 0.038 mm reached up to 981.66 mg/kg after 5 min of attrition. Optimal dosage of collector ($C_5H_{11}OCS_2K$) and modifier ($Na_2S$ and $CuSO_4$) in froth flotation process for the selective separation of the chipped progeny particles from the parent fragments were determined both as 200 g/ton. Arsenic removal efficiency in froth flotation process was 38.47% and it was increased to 72.74% in additional flotation process, scavenging. Average arsenic concentration after overall process - wet sieving, attrition and froth flotation - was estimated to 16.45 mg/kg.

• Journal of Soil and Groundwater Environment
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• v.14 no.2
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• pp.17-25
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• 2009

The applicability of soil washing/flushing to treat a contaminated soil with cadmium (Cd) and copper (Cu) using a mixture of organic/inorganic extractant was evaluated in laboratory-scale batch and column tests. Citric acid was the effective extractant to remove Cd and Cu from the soil among various organic acids except EDTA. Carbonic acid was chosen as inorganic extractant which was not only low toxicity to environment, but also increasing soil permeability. Moreover, the optimum ratio of organic and inorganic extractant to remove Cd and Cu was 10 : 1, and this ratio of organic and inorganic extractant achieved removal efficiencies of Cd (46%) and Cu (39%), respectively. The increasing flow rate of extractant could explain the phenomena of soil packing when carbonic acid was used with organic extractant (i.e. EDTA and citric acid). Therefore, a mixture of organic extractant with inorganic extractant, especially carbonic acid, could resolve a problem of soil packing when this extractant was applied to a field application to remove Cd and Cu using in-situ soil flushing process.

• Journal of Soil and Groundwater Environment
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• v.15 no.1
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• pp.50-56
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• 2010

Oil contamination soil has been one of the most environmental social issues for decades in the inside and outside of country. The law of soil environmental preservation was carried out in the 1990s and the government controlled not only soil environment management and the remediation of contaminated soil but also promoted the development of remedial technology and cleanup business of contaminated soil by national policy. In addition to agriculture areas, the main oil contaminated sites are a gas station, oil reservoir, petro-chemical complex, site of railway carriage base and military camp. The contamination-frequency of agriculture area and effect sites are low but it has significantly important area on account of producing food for human beings. Therefore, we should be concerned about oil contamination damage of agriculture area. The oil contamination damage of agriculture area influenced drop of birth and breeding since the oil directly adheres to seeds and farm products even diffusion of contaminated soil to cultivation area. The studies of the crops and the food vegetation has not enough detailed data caused by the incident of oil contamination. This study investigated the effect of oil in germination and growth of selected plant seeds. In this study, we try to verify whether the oil contamination by accidents on farmland influenced the damage of farm produce and the mutual relation both oil contaminated soil or the vegetation of crops. The impact of oil on plant development was followed by phytotoxicity assessments. The plants exhibited visual symptoms of stress, growth reduction and perturbations in developmental parameters. The increase of the degree of pollution induced more marked effects in plants, likely because of the physical effects of oil. The relationships between the phytotoxicity contents of plants and growth reduction suggest a chemical toxicity of fuel oil. In addition, while cleaned up the contaminated soil under the standard of contaminated soil we examined it was suitable for region standard and it may have practical possibility for fill material of construction of afforestation and molding soil of landfill.

• Clean Technology
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• v.23 no.3
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• pp.302-307
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• 2017

This study was conducted to evaluate the feasibility of in situ soil flushing for TPH-contaminated soil remediation with column test. The soil texture of the soil was sand and the initial TPH concentration was $9,369mg\; kg^{-1}$. 0.1% Tween-80 was selected as surfactant solution. And the acrylic and the glass syringe columns were used as reactors. In the acrylic column test, 35% of the initial TPH was removed in 1 PV of flushing and approximately 40% in 5 PV and finally 7 PV showed about 60%. The glass column test showed 3 ~ 12% higher removal efficiency than that of acrylic test until 5 PV of flushing. However, there was no difference in TPH removal efficiency when 7 PV of surfactant was finally flushed. Both of alum only and alum+polymer mixed surfactants showed also the best coagulation efficiency in $150mg\;L^{-1}$ of concentraion. When Tween 80 was newly dissolved in 0.1% to the recovered solution after the coagulation treatment, the removal efficiency was increased from 32.0% to 41.0% in comparison to the new 0.1% Tween 80 solution without reuse by coagulation treatment.

• Journal of Soil and Groundwater Environment
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• v.17 no.3
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• pp.21-31
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• 2012

This paper presents the short-term and long-term measures to determine the fugitive dust concentration in a contaminated site, which is a crucial step for the determination of particulate emission factor (PEF) for risk assessment. As a long-term measure, USEPA method employing Q/C value (inverse of the ratio of the geometric mean air concentration to the emission flux at center of a 0.5-acre square source) seems to be suitable as it reflects regional-specific meteorological conditions. However, it requires nation-wide database collection and interpretation. Use of ASTM method is an alternative as a short-term measure. The method is readily field-applicable as PEF calculation equation is simple and input parameters can be easily derived at the site of interest as well without the nation-wide efforts. Using ASTM method, PEF at the Former Janghang Smelter Site was determined. According to various mode of aggregate size distribution and fractions of vegetative cover, which are the most important factors in PEF calculation, PEF values at the Former Janghang Smelter Site varied greatly. When the mode of aggregate size distribution was set at 0.25 mm, PEF values at the Former Janghang Smelter Site was 5~20 times higher than the default PEF value (i.e., 35 ${\mu}g/m^3$) shown in the current Korean Soil Contamination Risk Assessment Guidance. On contrast, when the mode was set at 2 mm, PEF values at the Former Janghang Smelter Site was 160~640 times lower than the default PEF value in the Korean Guidance.