• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.869-872
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• 2004

A study on the solidification of sludge by reactive amendment agent was carried out in this paper. The reactive amendment agent used in this study is mainly composed of inorganic solidification agent and reactive adsorptive material. The reactive agent has a function of soil-cement-agent solidification and harmlessness of contaminant in waste. The reactive agent is environmentally friendly material to the surrounding environment. In this study, a series of tests and experiments including unconfined compressive strength, permeability, pH test, constituent analysis, leaching test were carried out to analyse engineering and environmental characteristics of solidified sludge treated reactive agent. The result of this research shows that the solidified sludge treated reactive agent is increased in strength and decreased in contaminant concentration.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.45-57
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• 1996

Flow characteristics and contamination behavior in a three-dimensional room with the desk-type obstacle have been investigated numerically by the k-${\varepsilon}$ two equation turbulence model. The room model has one supply opening on the ceiling and two exhaust openings on the side walls. Thirty six sets of calculation have been performed for twelve contamination sources of $1{\times}10^{-4}kg_c/(m^3{\cdot}s)$ strength at different inlet velocities(0.1, 1, 10m/s). This study can conclude that the source points of contaminant are located near the obstacle edge of Z-axis, at which the maximum contaminant diffusion fields are occured.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2001.11a
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• pp.77-82
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• 2001

This paper is contents that measure the ventilation rates and temperature by driving condition of exhaust fan, vapor, contaminant occurrence amount of carbon dioxide etc. In kitchen of apartment house. The ventilation rates in the apartment kitchen measured by Tracer Gas Method. And, temperature of when cook by gas table hood lower part 10cm and floor upside 10cm of kitchen central part, 120cm, 210cm heights measure. As ventilation rates measurement result, ventilation number of times was 0.7(number of times/hour) when did not to operate exhaust fan. but we were measured by 2.3(number of times/hour) when drove strongly. As temperature measurement result at cooking by gas table, temperature showed highest in hood lower part 10cm of case that do not operate exhaust fan. Temperature at kitchen central was most low in 10cm height in talc floor, and 210cm were measured highest. Concentration of carbon dioxide is very high by 4,350ppm after measurement time 10 minutes in state who do not operate exhaust fan at cooking by gas table.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.405-410
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• 2006

This paper presents a control algorithm of supply and exhaust diffusers by recognizing a contaminant source location. CFD analysis has been conducted to calculate steady state airflow and concentration distributions in a model room, which has two supply and two exhaust openings on the ceiling. Calculations have been performed for five cases out of nine different ventilation modes by combining on/off control of the supply and exhaust openings. Local mean residual life times are obtained and compared at 9 internal points for each ventilation case. Depending on the contaminant source location, the ventilation system is operated at an optimum ventilation mode, which can results in maximum exhaust performance.

• Particle and aerosol research
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• v.14 no.4
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• pp.181-189
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• 2018

In this study, the risk rates of different contamination sources of the contaminant in a minienvironment were analyzed through Computational Fluid Dynamics (CFD) simulation. The airflow pattern characteristics can only predict the qualitative variation of contaminant concentration, but cannot evaluate the quantitative variations in the risk rate of sources. From the results, the ambient contamination sources mainly affect wafers in the Front Opening Unified Pod (FOUP), whereas the internal contamination sources mainly affect wafers laid on the robot arm in the minienvironment. And the purging plenum system is very useful in protecting the wafers in the FOUP from contaminants transferred from the Fan Filter Unit (FFU). However, this system is unable to protect the wafers on the robot arm from internal contaminants and the wafers in the FOUP from sources of the interface between the FOUP and the minienvironment.

• Proceedings of the KSEEG Conference
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• 2002.06a
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• pp.81-100
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• 2002

While most of regulatory communities in abroad recognize ' 'natural attenuation " to include degradation, dispersion, dilution, sorption (including precipitation and transformation), and volatilization as governing Processes, regulators prefer "degradation" because this mechanism destroys the contaminant of concern. Unfortunately, true degradation only applies to organic contaminants and short- lived radionuclides, and leaves most metals and long-lived radionuclides. The natural attenuation Processes may reduce the potential risk Posed by site contaminants in three ways: (i)contaminants could be converted to a less toxic form througy destructive processes such as biodegradation or abiotic transformations; (ii) potential exposure levels may be reduced by lowering concentrations (dilution and dispersion); and (iii) contaminant mobility and bioavailability may be reduced by sorption to geomedia. In this review, authors will focus will focul on "sorption" among the natural attenuation processes of hazardous inorganic contaminants including radionuclides. Note though that sorption and transformation processes of inorganic contaminants in the natural setting could be influenced by biotic activities but our discussion would limit only to geochemical reactions involved in the natural attenuation. All of the geochemical reactions have been studied in-depth by numerous researchers for many years to understand "retardation" process of contaminants in the geomedia. The most common approach for estimating retardation is the determination of distrubution coefficiendts ($K_{d}$) of contaminants using parametric or mechanistic models. As typocally used in fate and contaminant transport calculations such as predictive models of the natural attenuation, the $K_{d}$ is defined as the ratio of the contaminant concentration in the surrounding aqueous solution when the system is at equilibrium. Unfortunately, generic or default $K_{d}$ values can result in significant error when used to predict contaminant migration rate and to select a site remediation alternative. Thus, to input the best $K_{d}$ value in the contaminant transport model, it is essential that important geochemical processes affecting the transport should be identified and understood. Precipitation/dissolution and adsorption/desorption are considered the most important geochemical processes affecting the interaction of inorganic and radionuclide contaminants with geomedia at the near and far field, respectively. Most of contaminants to be discussed in this presentation are relatively immobile, i.e., have very high $K_{d}$ values under natural geochemical environments. Unfortunately, the obvious containment in a source area may not be good enough to qualify as monitored natural attenuation site unless owner demonstrate the efficacy if institutional controls that were put in place to protect potential receptors. In this view, natural attenuation as a remedial alternative for some of sites contaminated by hazardous-inorganic components is regulatory and public acceptance issues rather than scientific issue.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.346-349
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• 2004

Surfactant-enhanced electrokinetic (EK) process was investigated to remove polycyclic aromatic hydrocarbons (PAHs) from low-permeable soils. Phenanthrene and kaolinite were selected as a representative PAH and a model soil, respectively. A nonionic surfactant Tergitol 15-S-12 was applied to improve the solubility of phenanthrene and sodium chloride was used as an electrolyte at the various concentrations from 0.001 to 0.1M. The addition of electrolyte affected both the removal efficiency and operation cost. When electrolyte was introduced, the electrical potential gradient became low and thus power consumption was reduced. However, as electrolyte concentration increased, the electroosmotic flow also decreased, so the removal efficiency of contaminant decreased. Therefore, the removal efficiency and power consumption should be considered simultaneously to determine the iptimum surfactant concentration, so a relatively lower concentration of electrolyte than certain value is desired.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.415-418
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• 2000

There has been a steady increase in geoenvironmental engineering projects where geotechnical engineering has been combined with environmental concerns. Many of these projects involve some investigation on contaminant around unplaned waste landfill. In this study, investigation and test on contamination characteristics of wastes dumped at municipal site were carried out. Testing wastes were sampled at this site. Sampled wastes were divided into waste itself and soil to analysis the characteristics of waste and soil. As a result of this study, the concentration of soil and waste were investigated. And measured concentration were compared with related concentration criteria.

• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.155-163
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• 2003

The groundwater flow and contaminant transport numerical models have been established for analyzing the movements of pollutants in subsurface soil at Daeduk site. The groundwater flow and concentration of U-234 using the numerical models were simulated around Daeduk nuclear facilities. The computed groundwater flow was mainly advected toward the direction of east and southeast around HANARO in the site. The radioactive material entered into the subsurface soil was transported along the same direction with groundwater flow. The radioactive material deposited on the surface from the calculated concentration distributions was not affected by surrounding environment of the site.

• Journal of computational fluids engineering
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• v.6 no.4
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• pp.1-7
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• 2001

Wind flow perturbations, recirculations and turbulence generated by buildings often dominate air pollutant distributions around buildings. This paper describes dispersion of contaminants in the vicinity of a building by solving the concentration equation based on previously simulated wind flow field. Turbulence closure is achieved by using the standard k-ε two-equation model. The paper shows application of the CIP method for solving a species concentration equation of contaminant gas around a rectangular building for two different sources under conditions of neutral atmospheric stratification. Results have been compared to the experimental data and the previous numerical results by hybrid scheme. The computational results of concentration profiles by the CIP method agree well with experimental data.