• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.25-39
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• 2003

Risk and exposure assessment for subsurface environment is very important for both aspects of health and environmental protection as well as making decision of remedial goal for engineering activities. Exposure due to hazardous chemicals in the subsurface environment is essential to assess risk lev121 to individual person, especially from soil and groundwater environmental media. In this paper, the status of soil and groundwater contamination is presented to discuss on the problem for environmental risk assessment. The methodologies of fate and exposure models are also discussed by conducting the case studies of exposure assessment for heavy metals, organic compounds, and dioxin compounds. In addition, the structure of exposure models and available data for model calculation are examined to make clear more realistic exposure scenarios and the application to the practical environmental issues. Three kinds of advanced remediation techniques for soil and groundwater contamination are described in this paper, The most practical method for VOCs is the bio-remediation technique in which biological process due to consortium of microorganisms can be applied. For more effective remediation of soil contaminated by heavy metals we have adopted the soil flushing technique and clean-up system using electro-kinetic method. We have also developed the advanced techniques of geo-melting method for soil contaminated by DXNs and PCB compounds. These techniques are planed to introduce and to apply for a lot of contaminated sites in Japan.

• Journal of Ecology and Environment
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• v.41 no.3
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• pp.93-98
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• 2017

Background: Although phytoremediation is a promising method for pollution control, biomass produced by the remediation process must be managed; otherwise, it will eventually return to the environment and cause secondary pollution. Therefore, research and policy development for the post-remediation management of biomass are both required. Results: While there are many published studies of phytoremediation, research into post-remediation management is very limited. Therefore, a new study using biomass as a co-composting material was conducted and showed positive effects on soil characteristics and plant performance. However, despite its potential, research and policies to promote this form of management are still lacking. Conclusions: We suggest public engagement in support of "Post-phytoremediation management" legislation that stipulates management of biomass after phytoremediation, promotes recycling of biomass with known environmental risks, and includes specific policies developed for managers. Further research to support and inform such policies and laws is also required.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.226-229
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• 2001

For volume reduction of the wastewater generated on washing the soil contaminated with cobalt, recycling and reuse experiments of the wastewater were executed. Also. the soil remediation efficiency by repetitive washing with fresh citric acid was analyzed. The soil around TRIGA was sampled for the experiment. Results of recycling experiment by replacement-precipitation method were as follows. The remediation efficiency of 1st recycling wastewater was 97% and that of 2nd recycling wastewater was 94%. Also, To obtain remediation efficiency over than 90%, the 5th repetitive washing with fresh citric acid was needed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.356-359
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• 2003

Polycyclic aromatic hydrocarbons (PAHs) are representative hydrophobic organic carbons (HOCs). Surfactant-enhanced electrokinetic (EK) remediation is an innovative in-situ technology that can effectively remove HOCs from low-permeability soils. In this study, the electrokinetic remediation using Tergitol 15-S-12, a nonionic surfactant, was conducted for the removal of phenanthrene from kaolinite. Tergitol 15-S-12 was used at concentrations of 1.5, 2.0, 2.5 and 7.5 g/L to enhance the solubility of phenanthrene. When the surfactant solution was applied to EK system, high electrical potential gradient was maintained and the amount of electroosmotic flow decreased. Removal efficiency of phenanthrene was proportional to the concentration of Tergitol 15-S-12 because the solubility and mobility of phenanthrene was enhanced by surfactant micelle. Therefore, the suitable concentration of nonionic surfactant Tergitol 15-S-12 is expected to improve the removal efficiency of PAHs in EK remediation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.63-66
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• 2002

Developers have, for some time now, recognised the benefits of acquiring "brownfields" sites for future urban development. The term “brownfield” generally refers to sites that have been previously occupied and in most cases this occupation has been for industrial usage. A key issue that developers face when considering the acquisition of a former industrial site is contamination and the costs associated with remediating the land to a level that renders the site suitable for its proposed use. Understanding all of the issues and implications associated with the remediation of contaminated land can be quite daunting. The process of remediation brings together a number of stakeholders that all have some influence on the outcome of the works. The stakeholders include the vendor, the purchaser, the regulatory authorities i.e. EPA and council, the Site Auditor and local residents. Careful planning and negotiation with the above stakeholders should be considered before committing to any remediation project.n project.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.10a
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• pp.28-57
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• 2003

Germany as a densely populated and heavily industrialised country has a long and broad experience in handling contaminated sites. With this presentation we want to describe some main aspects of the soil protection policies and the remediation of contaminated sites in Germany. Due to the history of working on contaminated sites in Germany the Federal Soil Protection Act came into force in 1998. A lot of programmes and network in Germany and in Europe, funded by the State or the European Union, helped developing new measures and techniques for remediation and also for implementing regulations for the involved authorities. Questions like 'who is responsible？' and 'who has to pay for measurements and the remediation？' became more and more important. In the near future there will be an official European Soil Protection Policy (is expected in June 2004). Besides the contaminated sites also other soil protection policies as 'Reducing the land consumption' are pursued and an indicator is developed.and an indicator is developed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.290-293
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• 2000

After kaolin clay was compulsorily contaminated with Co$^{2+}$ion, the remediation characteristics by electrokinetic method were analyzed. Ethanoic buffer was injected in the soil column and $CH_3$COOH was continuously inputted in cathode reservoir to restrain the pH elevation. Since pH of the cathode side of the soil column was 4.0 at initial and was restrained by 6.5 at 43.6 hours, Precipitation, Co(OH)$_2$, was not formed in the column. Effluent rate increased with time passage and remediation in the column in initial time was mainly controlled by ion migration. 13.1% of total in the soil column was remediated in 10 hours, and the 6.8% of total in 20.8 hours, and the 71.7% of total in 43.6 hours, and the 94.6% of total in 43.6 hours. Meanwhile, the residual concentrations in the column calculated by the developed model were similar to those by experiment.t.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.34-37
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• 2005

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.242-246
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• 1999

For the fluorination of $CF_2Cl_2$, the yield of $CF_4$ was found to be increased with the contact time and the reaction temperature. When the mole ratio of HF/$CF_2Cl_2$ is 3 or above, the yield of $CF_4$ was attained to 100% at $370^{\circ}C$ and contact time of 3 seconds. In the case of the fluorination of $CCl_4$ with HF, the yield of $CF_4$ was obtained above 90% at the reaction temperature of $500^{\circ}C$, the contact time of 3 seconds, and the mole ratio of HF/$CCl_4$ of 5.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.619-623
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• 1998

The influences of reaction temperature, HF/DCM mole ratio, contact time and catalyst type on activity and selectivity of difluoromethane synthesis via hydrofluoriation of dichloromethane over fluorinated catalyst have been studied. It has been found that fluorinated $Cr/Al_2O_3$ catalysts, show better performance compared to pure fluorinated $Al_2O_3$ catalyst and then, non-treated catalysts demonstrate better than catalysts pretreated with hydrogen and air. The results show that the optimum reaction conditions are found as follows : reaction temperature at $340^{\circ}C$, mole ratio of HF/DCM 5 or above and contact time 20 sec. or above. With these conditions the maximum attainable yield of difluoromethane has been found to be greater than 80%. In particular, the activity and the selectivity of difluoromethane do not change with the reaction time on stream up to 8 hours.