• Journal of Environmental Health Sciences
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• v.22 no.3
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• pp.116-122
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• 1996

This study has been focused on the applicability of microwave treatment of soil contaminated by volitile organic chemicals. Substrates studied were sand and sandy soil. These substrates were impregnated with toluene, tetrachloroethylene, o-xylene and p-dichlorobenzene. The microwave treatment was conducted in a modified domestic microwave oven: 2450 MHz, 700 W. The sandy soil temperature added water went up rapidly to about 130$\circ$C for 4 minutes. And then, the temperature appeared to plateau out. A series of tests were performed to depict the effectiveness of microwave treatment technique to organic contaminants from soils. Removal efficiencies in sandy soil and sand were increased with increasing water content and exposure time. Microwave radiation penetrates the soil and heats water throughout the matrix. 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. And the vapour pressure of impregnated organic contaminants becomes lower. the removal efficiency becomes poor.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.73-81
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• 2013

Various remediation methods have been applied to clean soils contaminated with pollutants. They remove contaminants from the soils by utilizing physicochemical, biological, and thermal processes and can satisfy soil remediation standards within a limited time; however, they also have an effect on the biological functions of soils by changing soil properties. In this study, changes of the biological properties of soils before and after treatment with three frequently used remediation methods-soil washing, land farming, and thermal desorption-were monitored to investigate the effects of remediation methods on soil biological functions. Total microbial number and soil enzyme activities, germination rate and growth of Brassica juncea, biomass change of Eisenia andrei were examined the effects on soil microorganisms, plant, and soil organisms, respectively. After soil washing, the germination rate of Brassica juncea increased but the above-ground growth and total microbial number decreased. Dehydrogenase activity, germination rate and above-ground growth increased in both land farming and thermal desorption treated soil. Although the growth of Eisenia andrei in thermal desorption treated soil was higher than any other treatment, it was still lower than that in non-contaminated soil. These results show that the remediation processes used to clean contaminated soil also affect soil biological functions. To utilize the cleaned soil for healthy and more value-added purposes, soil improvement and process development are needed.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1463-1474
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• 2008

In order to investigate stabilization effect and sustainability on As-contaminated farmland soils which were affected the abandoned mine site and stabilized by zerovalent iron(ZVI) and industrial by-products, batch-scale and pilot-scale tests were carried out. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used in treatment materials to reduce the As leaching. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. The results of batch-scale tests was shown that the reduction of As concentration was observed in all samples and it was expected that ZVI and steel refining slag were more effective than other treatment materials to stabilize As compounds. In pilot-scale tests, columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag in the same mixing ratio of 3%. Distilled water was discharged into the columns with the velocity of 0.3 pore volume/day. During the test, pH, EC, Eh and As concentration were measured in the regular term(1pore volume). after six months, pilot-scale tests were retested to investigate sustainability of treatment materials. As a result, It was shown that the leachate from control column was continuously released during the test period and its concentration was greater than $100ug{\cdot}L^{-1}$ which was exceeded the national regulation of water discharged to river or stream ($50ug{\cdot}L^{-1}$). On the other hand, soil treated with ZVI and steel refining slag showed that the concentrations of leachate were lower than national regulation of water discharged to river or stream. Therefore it was expected that ZVI and steel refining slag could be applied to the farmland site as the alternative treatment materials.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.401-406
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• 2000

Spilling of petroleum hydrocarbons such as gasoline, motor oils, and diesel fuel from underground storage tanks (USTs) is a major source of contamination to ground water and soils. In response to the need of developing an effective and economical cleanup technique, this study investigates the effectiveness of using sonication to enhance the soil flushing method. The study involves laboratory testing, and the testing was conducted using a specially designed and fabricated device to determine the effect of sonication on contaminant removal. The sonication was applied at 20 kHz frequency under different power levels. Test soil was Joomoonjin Sand, and diesel fuel was used as a contaminant of soil flushing test. The results of the investigation show that sonication enhanced the contaminant removal from soils significantly, and the degree of enhancement varied with power levels of sonication. Based on the results of the study, it is concluded that the flushing method with sonication has a great potential to become an effective method for removing petroleum hydrocarbons from the contaminated ground.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1512-1517
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• 2008

Laboratory column tests were conducted in this study using $Cl^-$ tracers on Jumunjin sand to analyze contaminant transport in mixed contaminated soils. Results obtained from clean soils and soils containing residual diesel verified heterogeneous distribution of residual diesel, and clear acceleration of solute movement. In addition, asymmetric breakthrough curves indicated development of immobile region where solute movement becomes stagnant and creates tailing phenomenon.

• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.62-73
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• 2020

PAHs commonly found in industrial sites such as manufactured gas plants (MGP) are potentially toxic, mutagenic and carcinogenic, and thus require immediate remediation. In-situ chemical oxidation (ISCO) is known as a highly efficient technology for soil and groundwater remediation. Among the several types of oxidants utilized in ISCO, persulfate has gained significant attention in recent years. Peroxydisulfate ion (S₂O₈^2-) is a strong oxidant with very high redox potential (E⁰ = 2.01 V). When mixed with Fe²⁺, it is capable of forming the sulfate radical (SO₄^-·) that has an even higher redox potential (E⁰ = 2.6 V). In this study, the influence of various iron activators on the persulfate oxidation of PAHs in contaminated soils was investigated. Several iron sources such as ferrous sulfate (FeSO₄), ferrous sulfide (FeS) and zero-valent iron (Fe(0)) were tested as a persulfate activator. Acenaphthene (ANE), dibenzofuran (DBF) and fluorene (FLE) were selected as model compounds because they were the dominant PAHs found in the field-contaminated soil collected from a MGP site. Oxidation kinetics of these PAHs in an artificially contaminated soil and the PAH-contaminated field soil were investigated. For all soils, Fe(0) was the most effective iron activator. The maximum PAHs removal rate in Fe(0)-mediated reactions was 92.7% for ANE, 83.0% for FLE, and 59.3% for DBF in the artificially contaminated soil, while the removal rate of total PAHs was 72.7% in the field-contaminated soil. To promote the iron activator effect, the effects of hydroxylamine as a reducing agent on reduction of Fe³⁺ to Fe²⁺, and EDTA and pyrophosphate as chelating agents on iron stabilization in persulfate oxidation were also investigated. As hydroxylamine and chelating agents (EDTA, pyrophosphate) dosage increased, the individual PAH removal rate in the artificially contaminated soil and the total PAHs removal rate in the field-contaminated soil increased.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.15-28
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• 2007

The study is for contaminations of major, rare earth and trace elements of the farmland soils from the Boeunjeil mine area. The results are compared with the soils of Chungjoo, Deokpyeong, Boeun and Chubu areas. Fe and S contents of the contaminated area are high relative to those from the uncontaminated areas, Chungjoo and Boeun areas. Trace elements of the contaminated area are high relative to those from uncontaminated area, Chunajoo, Deokpyeong, Boeun and Chubu areas. The trace elements ares divided into Cd, Ni, Sr, U, V, Zn and As, Co, Cu, Mo, Pb, Sb, based on these dispersion and correlation. Two groups show the positive correlation. Enrichment factor of potentially toxic elements from contaminated area is >5 value, but <4 value in the uncontaminated area. In the geoaccumulation index of the minor elements, the contaminated area has >1 value and the uncontaminated area has <1 value except Mn. Enrichment index of potentially toxic elements(As, Cd, Co, Cu, Ni, U, Zn) ranges from 0.3 to 87.0 in the contaminated area and from 0.4 to 3.9 in the uncontaminated area. Overall results show that the high contents of farmland soils for the elements(Fe, S, As, Cd, Co, Cu, Ni, U, Zn) indicate the contamination by coal-related activities.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.127-136
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• 1999

In the past several years phytoremediation, defined as the use of plants for removing contaminants from media such as soils or water, has attracted a great deal of interest as a potentially useful remediation technology We attempted to assess the effectiveness of phytoremediation of diesel-contaminated soils in a green house. Screening test for selecting an appropriate plant was performed by observing the harmful effects of diesel dosage on the growth of 4 plants. Alfalfa was selected as a potentially useful plant among corn and barnyard grasses due to its high tolerance to the toxicity of diesel in growth. Bioremediation of the artificial diesel-contaminated soil packed in the PVC columns(0.3m in diameter $\times$ 1m in length) with air supplied, alfalfa planted, and alfalfa and air supplied was investigated for 100 days. The results of the column test showed plant effects on enhancing the biodegradation of diesel in the contaminated soils compared to the control column which had no plant. Injecting air to the columns during phytoremediation also showed additional effects on the removal rate of diesel. Comparison of microbial activity in each test column showed a beneficial effect of plants in the soil remediation processes. This results can be explained microbial activity in rhizosphere is a crucial factor for removing diesel.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.413-424
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• 2021

In order to enhance rhizoremediation performance, which remediates contaminated soils using the interactions between plants and microorganisms in rhizosphere, it is required to develop effective microbial resources that simultaneously degrade contaminants and promote plant growth. In this study, heavy metal-resistant rhizobacteria, which had been cultivated in soils contaminated with heavy metals (copper, cadmium, and lead) and diesel were isolated from rhizospheres of maize and tall fescue. After that, the isolates were qualitatively evaluated for plant growth promoting (PGP) activities, heavy metal tolerance, and diesel degradability. As a result, six strains with heavy metal tolerance, PGP activities, and diesel degradability were isolated. Strains CuM5 and CdM2 were isolated from the rhizosphere soils of maize, and were identified as belonging to the genus Cupriavidus. From the rhizosphere soils of tall fescue, strains CuT6, CdT2, CdT5, and PbT3 were isolated and were identified as Fulvimonas soli, Cupriavidus sp., Novosphingobium sp., and Bacillus sp., respectively. Cupriavidus sp. CuM5 and CdM2 showed a low heavy metal tolerance and diesel degradability, but exhibited an excellent PGP ability. Among the six isolates, Cupriavidus sp. CdT2 and Bacillus sp. PbT3 showed the best diesel degradability. Additionally, Bacillus sp. PbT3 also exhibited excellent heavy metal tolerance and PGP abilities. These results indicate that the isolates can be used as promising microbial resources to promote plant growth and restore soils with contaminated heavy metals and diesel.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.469-480
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• 2003

Laboratory leaching experiment study carried out to estimate a extent of heavy metals that could be leached out when acid rain(pH 5.0-3.0) and strong acidic solution(pH 2.5-1.0) reacted with tailings and contaminated soils from abandoned metal mines. In slightly to moderately acid conditions(pH 5.0-3.0), As, Pb and Zn dissolutions became significantly increased with decreased pH in tailing, while dissolution of these elements was very limited in contaminated soil. These results suggested that moderately acid rainwater leaches Pb, As and Zn from the tailings, while these elements would remain fixed in contaminated soil. In the pH range of 2.5-1.0(strongly acid condition), Zn, Cd and Cu concentrations of leachate rapidly increased with decreased pH in contaminated soil, while Pb, As and Co dissolutions became importantly increased in tailings. The experimental solubility of Zn. Cd and Cu was very low even at very low pH values(up to pH 1), except for CY4(Cheongyang mine). These can result from an incomplete dissolution or the presence of less soluble mineral phases. So, the solubility of heavy metals depends not only on the pH values of leachate but also on the speciation of metals associated with contaminated soils and tailings. The relative mobility of each element within failings at the pH 5.0-3.0 of the reaction solution was in the order of Pb>Zn>Cd>Co=Cu>As. In case of pH 2.5-1.0 of the reaction solution, the relative mobility of each element within contaminated soils and tailings were in the order of Zn＞Cd>Cu>Co>Pb=As for contaminated soils, and Pb>Zn>Cd>hs>Co>Cu for tailings. The obtained results could be useful for assessing the environmental effects and setting up the restoration plan in the areas.