• Journal of Korean Society of Water and Wastewater
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• v.23 no.5
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• pp.539-545
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• 2009

A feasibility of a pilot scale two-phase anaerobic digestion with ultra filtration system treating garbage leachate were evaluated. The treatment system consisted of a thermophilic acidogenic reactor, a mesophilic methanogenic reactor, and an UF membrane. The average COD removal efficiency of the treatment system was 95% up to the OLR of 3.1 g COD/L/d. The higher COD removal efficiency with membrane unit resulted from the removal of some portion of soluble organics by membrane as well as particulate materials. When the membrane unit was in operation, bulk liquid in acidogenic and methanogenic reactors was partially interchanged, which maintained the acidogenic reactor pH over 5.0 without external chemical addition. Also, with the production of methane in the acidogenic reactor, the organic loading rate of the methanogenic reactor reduced. The initial flux of the membrane unit was $50{\sim}60L/m^2/hr$, but decreased to $5 L/m^2/hr$ after 95 days of operation due to clogging caused by particulate materials such as fibrous materials in garbage leachate. To prevent clogging caused by particulate materials, a pretreatment system such as screening is required. With the improvement with membrane unit operation, the two-phase anaerobic digestion with ultra filtration system is expected to have the possibility of treating garbage leachate.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.414-423
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• 2006

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925, Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower and the motion of grout is also a function of formation permeability. Viscosity of grout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this thesis, characteristics of new cement grout material that is developed recently is studied: injectable volume of new grout material is tested in two different sizes of sands, and the method to calculate injectable volume of grout is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to be an exponential function of time. And lumped parameter $\theta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressure.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.113-124
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• 2006

The feasibility of the up- and down-flow constructed wetland was examined fur rural wastewater treatment in Korea. Many constructed wetland process was suffered from substrate clogging and high plant stresses because of long term operation. The up- and down-flow constructed wetland process used porous granule materials (charcoal pumice : SSR=10:20:70) for promoting intake rate of nutrient to plant, and especially flow type was designed continuously repeating from up-flow to down-flow. $BOD_5$ and SS was removed effectively by the process with the average removal rate being about 75% respectively. The wetland process was effective in treating nutrient as well as organic pollutant. Removal of TN and TP were more effective than other wetland system and mean effluent concentrations were approximately 7.5 and $0.4mg\;L^{-1}$ which satisfied the water quality standard for WWTPs. The treatment system did not experience any clogging or accumulations of pollutants and reduction of treatment efficiency during winter period because constructed polycarbonate glass structure prevented temperature drop. Considering stable performance and effective removal of pollutant in wastewater, low maintenance, and cost-effectiveness, the up- and down-flow constructed wetland was thought to be an effective and feasible alternative in rural area.

• Journal of the Korean Geosynthetics Society
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• v.8 no.2
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• pp.41-46
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• 2009

In this paper, a series of model tests were performed in laboratory to evaluate promoting consolidation of compaction pile methods for soft ground improvement. For the model tests, composite soil samples that have 10% replacement area ratio were prepared by using sand, gravel, and sandy gravel for the materials of compaction piles. After loading to each composite soil sample, the excess pore pressure dissipation and settlement were investigated. In addition, the behavior of clay mixed with each compaction pile was also monitored at the end of consolidation to evaluate clogging phenomenon. As a test result, the effects for decreasing settlement and promoting consolidation by GCP were prominent, and the mixed clay was not monitored in all of the three compaction piles.

• KSBB Journal
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• v.8 no.4
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• pp.351-357
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• 1993

Three immobilization techniques and free cell system were tested to determine the most effective technique for the treatment of pulp waste effluent. The tests were conducted using Phanerochaete chrysosporium as a biocatalyst in a process designed to treat pulp waste effluent. The results show that Ca-alginate gel was the best immobilization material. The chosen material improved the stability and increased the removal efficiency of the system. The experiment using the chosen material was mom- bored for 400 hours with no significant changes in the state of the fungus. Common problems with other immobilization materials and free cell system were oxygen transfer resistance caused by air channelling and clogging in the bioreactor.

• Geomechanics and Engineering
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• v.33 no.1
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• pp.65-75
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• 2023

Recycled concrete aggregate (RCA) is widely used as a construction material in road construction, concrete structures, embankments, etc. However, it has been reported that calcite (CaCO₃) precipitation from RCA can be a cause of clogging when used in drainage applications. An accelerated calcite precipitation (ACP) procedure has been devised to evaluate the long-term geochemical performance of RCA in subsurface drainage systems. While the ACP procedure was useful for the French Drain application, there remained opportunities for improvement. In this study, key factors that control the formation of calcite precipitation were quantitatively evaluated, and the results were used to improve the current prototype ACP method. A laboratory parametric study was carried out by investigating the effects of reaction temperature and time on the formation of calcite precipitation of RCA, with determining an optimum reaction temperature and time which maximizes calcite precipitation. The improved ACP procedure was then applied to RCA samples that were graded for Type I Underdrain application, to compare the calcite precipitation. Two key findings are (1) that calcite precipitation can be maximized with the optimum heating temperature (75℃) and time (17 hours), and (2) the potential for calcite precipitation from RCA is not as significant as for limestone. With the improved ACP procedure, the total amount of calcite precipitation from RCAs within the life cycle of a drain system can be determined when RCAs from different sources are used as pipe backfill materials in a drain system.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.5-13
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• 2007

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925. Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower one and the motion of grout is also a function of formation permeability. Viscosity of pout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this paper, characteristics of new cement grout material that has been developed recently are studied: injectable volume of new grout material is tested in two different grain sizes of sands; and the method to calculate injectable volume of grout Is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to increase as an exponential function of time. And lumped parameter $\delta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressures. Injection test results show that grout penetration rate is decreased by the increase of grout viscosity and clogging phenomena.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.35-36
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• 2018

Korea has many problems due to the asphalt pavement or impermeable pavement. Many methods are being implemented to improve water circulation. Among them, permeable packaging materials are used. However, existing permeable packaging materials have a problem of causing efflorescence and clogging the pores. The pores of the permeable packing material are clogged and the permeability is lost. This leads to economic problems and product problems. The purpose of this study was to develop a block to prevent efflorescence.

• Analytical Science and Technology
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• v.20 no.2
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• pp.124-130
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• 2007

In this study, we present the preparation and characterization of oxidized fullerene and fullerene dimer [$C_{120}$]. From the XRD data, other weak peaks with pristine fullerene [$C_{60}$] peaks were observed in the X-ray diffraction patterns for fullerene dimer [$C_{120}$]. SEM micrographs for the fullerene dimer [$C_{120}$] indicated that practically all the surface state was shown the drastic morphology changes and its outer surface is clearly visible and resulted in clogging and frost-like formation. From the MALDI-TOF mass spectra, the differences in the spectra recorded on two kinds of fullerene are due to the oxidation including chemical bonding and bridging between the $C_{60}$ molecules. We also obtained additional information from FT-IR spectra on functional component on the chemically modified surface of oxidized fullerene and fullerene dimer [$C_{120}$].

• Geomechanics and Engineering
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• v.25 no.1
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• pp.31-40
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• 2021

Injection grouting is one of the most common ground improvement practice to increase the strength and reduce the hydraulic conductivity of soils. Owing to the environmental concerns of conventional grout materials, such as cement-based or silicate-based materials, bio-inspired biogeotechnical approaches are considered to be new sustainable and environmentally friendly ground improvement methods. Biopolymers, which are excretory products from living organisms, have been shown to significantly reduce the hydraulic conductivity via pore-clogging and increase the strength of soils. To study the practical application of biopolymers for seepage and ground water control, in this study, we explored the injection capabilities of biopolymer-based grout materials in both linear aperture and particulate media (i.e., sand and glassbeads) considering different injection pressures, biopolymer concentrations, and flow channel geometries. The hydraulic conductivity control of a biopolymer-based grout material was evaluated after injection into sandy soil under confined boundary conditions. The results showed that the performance of xanthan gum injection was mainly affected by the injection pressure and pore geometry (e.g., porosity) inside the soil. Additionally, with an increase in the xanthan gum concentration, the injection efficiency diminished while the hydraulic conductivity reduction efficiency enhanced significantly. The results of this study provide the potential capabilities of injection grouting to be performed with biopolymer-based materials for field application.