• Journal of Soil and Groundwater Environment
• /
• v.11 no.2
• /
• pp.1-12
• /
• 2006

A model describing the distributions of surfactants and HOCs (hydrophobic organic chemicals) in surfactant/HOC/activated carbon systems for surfactant reuse in soil washing process was developed. The model simulation was conducted for the evaluation of the effect of concentrations of surfactant, HOC, or activated carbons. Phenanthrene as a target HOC, Triton X-100 as surfactant and three granular activated carbons with different particle sizes (4-12, 12-20, and 20-40 mesh) were used in the model simulation. The distributions of HOC were significantly affected by surfactant dosages, especially at around the CMC(s). The results of selectivities for phenanthrene were much larger than 1 at various concentrations of surfactants, phenanthrene and activated carbons, which mean that the selective adsorption of phenanthrene by activated carbons is a proper separation method from surfactant solution. The model can be applied for the design of the surfactant reuse process using activated carbons without extra experimental efforts.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.12 no.1
• /
• pp.1-6
• /
• 2014

A large amount of acidic waste solution is generated from the practical electrokinetic decontamination equipments for the remediation of soil contaminated with uranium. After filtration of uranium hydroxides formed by adding CaO into the waste solution, the filtrate was recycled in order to reduce the volume of waste solution. However, when the filtrate was used in an electrokinetic equipment, the low permeability of the filtrate from anode cell to cathode cell due to a high concentration of calcium made several problems such as the weakening of a fabric tamis, the corrosion of electric wire and the adhension of metallic oxides to the surface of cathode electrode. To solve these problems, sulfuric acid was added into the filtrate and calcium in the solution was removed as $CaSO_4$ precipitate. A decontamination test using a small electrokinetic equipment for 20 days indicated that Ca-removed waste solution decreased uranium concentration of the waste soil to 0.35 Bq/g, which is a similar to a decontamination result obtained by distilled water.

• Journal of Soil and Groundwater Environment
• /
• v.11 no.2
• /
• pp.22-37
• /
• 2006

The applicability of biobarrier or in situ microbial filter technology for the remediation of groundwater contaminated with chlorinated solvent was investigated through batch microcosm study. The efficiency and rates of reductive dechlorination of tetrachloroethylene (PCE) are known to be highly dependent on hydrogen concentration. In this study, the effect of electron donors on the reductive dechlorination of PCE was investigated using vermicompost (or worm casting) and peat as a biobarrier medium. The effect of organic acids (lactate, butyrate and benzoate), yeast extract and vitamin $B_{12}$ on the reductive dechlorination was investigated. In the absence of biobarrier medium (adsorbent), addition of electron donors stimulated the dechlorination rate of PCE compared to the control experiment (i.e., no electron donor added). Among the treatments, addition of lactate or lactate/benzoate as hydrogen donor exhibited the highest dechlorination rate ($k_1=0.0260{\sim}0.0266\;day^{-1}$). In case of using vermicompost as a biobarrier medium, amendment of lactate/benzoate exhibited the highest dechlorination rate following with a pseudo-first-order degradation rate constant of $k_1=0.0849\;day^{-1}$. In contrast, when Pahokee peat was used as a biobarrier medium, either butyrate or lactate addition exhibited the highest dechlorination rate with $k_1$ values of 0.1092 and $0.1067\;day^{-1}$, respectively. The results of this study showed the potential applicability of in situ biobarrier technology using vermicompost or peat as a barrier material for the remediation of groundwater contaminated with chlorinated solvent.

• Korean Journal of Plant Resources
• /
• v.32 no.1
• /
• pp.1-8
• /
• 2019

This study was performed to select the effective plant for phytoremediation of heavy metal contaminated areas. After cultivation of fifteen Compositae plants on soil contaminated with heavy metals for 8 weeks, the growth response and accumulation ability of each parts for heavy metal, such as arsenic, cadmium, copper, lead, and zinc were analyzed. Except Adiantum capillus-veneris, growth of Aster incisus, Coreopsis drumondii), Dendranthema indicum, Saussurea pulchella were relatively fine. Arsenic accumulation ability was the highest by Artemisia gmelini ($25.52mg{\cdot}kg^{-1}$ DW) in underground part, and D. sichotense ($3.35mg{\cdot}kg^{-1}$) in aerial part. Cadmium was the highest by Aster magnus ($2.50mg{\cdot}kg^{-1}$) in aerial part. Aerial and underground part of S. pulchella showed the highest copper accumulation (24.29, $99.92mg{\cdot}kg^{-1}$). In lead, 1.43 (A. magnus)${\sim}5.00mg{\cdot}kg^{-1}$ (S. deltoides) were accumulated in aerial part among fifteen Compositae plants. Aster hayatae ($140.09mg{\cdot}kg^{-1}$), Aster yomena ($109.07mg{\cdot}kg^{-1}$), A. magnus ($100.21mg{\cdot}kg^{-1}$) are absorbed more than $100mg{\cdot}kg^{-1}$ of Zinc. Therefore, they are considered to be phytoremediation material of zinc contaminated areas.

• The Journal of Engineering Geology
• /
• v.14 no.1
• /
• pp.29-46
• /
• 2004

It is important to identify geometries of fracture that act as a conduit of fluid flow for characterization of ground water flow in fractured rock. Fracture geometries control hydraulic conductivity and stream lines in a rock mass. However, we have difficulties to acquire whole geometric data of fractures in a field scale because of discontinuous distribution of outcrops and impossibility of continuous collecting of subsurface data. Therefore, it is needed to develop a method to describe whole feature of a target fracture geometry. This study suggests a new approach to develop a method to characterize on the whole feature of a target fracture geometry based on the Fourier transform. After sampling of specimens along a target fracture from borehole cores, effective frequencies among roughness components were selected by the Fourier transform on each specimen. Then, the selected effective frequencies were averaged on each frequency. Because the averaged spectrum includes all the frequency profiles of each specimen, it shows the representative components of the fracture roughness of the target fracture. The inverse Fourier transform is conducted to reconstruct an averaged whole roughness feature after low pass filtering. The reconstructed roughness feature also shows the representative roughness of the target subsurface fracture including the geometrical characteristics of each specimen. It also means that overall roughness feature by scaling up of a fracture. In order to identify the characteristics of permeability coefficients along the target fracture, fracture models were constructed based on the reconstructed roughness feature. The computation of permeability coefficient was performed by the homogenization analysis that can calculate accurate permeability coefficients with full consideration of fracture geometry. The results show a range between $10^{-4}{\;}and{\;}10^{-3}{\;}cm/sec$, indicating reasonable values of permeability coefficient along a large fracture. This approach will be effectively applied to the analysis of permeability characteristics along a large fracture as well as identification of the whole feature of a fracture in a field scale.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.11 no.3
• /
• pp.39-49
• /
• 2008

A study was carried out on the physico-chemical properties of soil and content of heavy metals and benzo(a)pyrene that might have been introduced through by-product fertilizers or air pollution to growing turfgrass at natural turfgrass playgrounds in elementary schools located at the western coast and eastern mountain areas in Jeollabuk-do, Korea. The soil of turfgrass playgrounds is composed of loamy sand, and the CEC and organic matters were very low. Compared to agricultural land in Korea, the concentrations of nitrogen, phosphorus and potassium were very low, requiring control in terms of nutrients. The contents of total and fraction heavy metals in soil were found to be background level. The reason may lie in the fact that unpolluted sand soil or sand was used to construct the foundation for the natural grass playground in the first place. However, any change in oxidation-reduction conditions or acceleration of decomposition of organic compounds may release some heavy metals from the soil and be transformed into forms that may be easily absorbed by plants or grass. It is believed that sustained monitoring and environment impact assessments should be carried out. The contents of benzo(a)pyrene in soil showed an average 0.60ng/g with a range between 0.06 to 1.47ng/g. The detected contents were found as background level.

• Journal of Environmental Science International
• /
• v.9 no.5
• /
• pp.437-441
• /
• 2000

A study on the removal of Pb ion from Pb-contaminated soil was carried out using ex-site extraction process. Tartaric acid (TA) and iminodiacetic acid sodium salt(IDA) as a washing agent were evaluated as a function of concentration reaction time mixing ratio of washing agent and recycling of washing agent. TA showed a better extraction performance than IDA. The optimum washing condition of TA and IDA were in the ratio of 1:15 and 1:20 between soil and acid solution during 1 hr reaction. The total concentrations of Pb ion by TA and IDA at three repeated extraction were 368.8 ppm and 267.5 ppm respectively. The recovery of Pb ion from washing solution was achieved by adding calcium hydroxide and sodium sulfide form the precipitation of lead hydroxide and lead sulfide and optimum amounts of sodium sulfide and calcium hydroxide were 7 g/$\ell$ for the TA washing solution and 4 g/$\ell$, 5g/$\ell$ for the IDA washing solution respectively. The efficiency of recycle for TA and IDA washing solution were 78.8% , 95.1%, and 89.2%, 96.6% at third extractions under $Na_2S$ and $Ca(OH)_2$, respectively.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.984-999
• /
• 2010

A long-term field demonstration experiment of selected stabilization method to reduce the heavy metal mobility in farmland soil contaminated by heavy metals around abandoned mine site was conducted. Field demonstration experiments were established on the contaminated farmland with the wooden plate(thickness=1cm) which dimension were width=200cm, Length=200cm, height=80cm and filled with treated soil, which was mixed with lime stone and steel refining slag except on control plot. Soil samples in the plots were collected and analyzed during the experiment period(2008. 2~2008. 8) after the installation of the plots. Field demonstration experiments results showed that the application ratio of lime stone 5% was effective for immobilizing heavy metal components in contaminated farmland soil.

• Journal of Environmental Science International
• /
• v.9 no.1
• /
• pp.43-47
• /
• 2000

A study on the remediation of heavily for ion contaminated soils from abandoned iron mine was carried out, using ex-situ extraction process. Also, oxalic acid as a complex agent was evaluated as a function of concentration, reaction time and mixing ratio of washing agent in order to evaluate Fe removability of the soil contaminated from the abandoned iron mine. Oxalic acid showed a better extraction performance than 0.1N-HCl, i.e., the concentrations of Fe ion extracted from the abandoned mine for the former at uncontrolled pH and the latter were 1,750 ppm and 1,079 ppm, respectively. The optimum washing condition of oxalic acid was in the ratio of 1:5 and 1:10 between soil and acid solution during l hr reaction. The total concentrations of Fe ion by oxalic acid and EDTA at three repeated extraction, were 4,554 ppm and 864 ppm, respectively. The recovery of Fe ions from washing solution was achieved, forming hydroxide precipitation and metal sulfide under excess of calcium hydroxide and sodium sulfide. In addition, the amounted of sodium sulfide and calcium hydroxide for the optimal revovery of Fe were 15g/$\ell$ and 5g/$\ell$ from the oxalic acid complexes, respectively.

• KSBB Journal
• /
• v.25 no.1
• /
• pp.73-78
• /
• 2010

In this study, recovering agent was produced with organic sludge and modified peat moss (MPM) in pilot plant mixer to recover oil contaminated soil, and field test of it was estimated using landfarming method. Oil contaminated soil recovering agent was thought to contain more microorganisms than raw waste sludge and was no problem to come onto the market because there were not any items of specified wastes. According to the results of TPH variation with time, it was observed the initial degradation velocity of oil with produced recovering agent was rapid up to 50% after 4 days, remarkably. Because the microorganisms in the organic sludge discharged from chemical plant already acclimated with oil, therefore, it could be estimated initial degradation velocity of recovering agent might be rapid. It was concluded that the oil contaminated soil recovering agent produced in this study have high marketability because of its two aspects on recycling of wastes and initial rapid degradation capacity.