• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.9 no.1
• /
• pp.1-8
• /
• 1997

A horizontal 2-D model which includes the wetting-drying treatment technique in the intertidal zone is established for the prediction of tidal changes and contaminant transport due to the development of Incheon coastal zone. The flow model is verified by the measurement data at Jeong-Do, and then the computed values are closely matched to the observed water elevations and velocities of main-flow direction. And then, the tidal change patterns are simulated using this model before and after the construction of the Youngjongdo New Airport and Shihwa Seadike. In the spring tide condition, pollutants transport pattern is also simulated for the arbitrary pollutants loads. By the analysis of this numerical simulation results, the velocities after development are decreased, and discharged pollutants are mainly transported by the advection along a narrow deep trough. Thus, this model can be used as the compatible prediction model for the tidal change and pollutant transport due to the development plan of Incheon coastal zone.

• Journal of Soil and Groundwater Environment
• /
• v.8 no.4
• /
• pp.12-20
• /
• 2003

This study presents a mathematical model for simulating the fate and transport of a reactive organic contaminant, TCE, degraded by cometabolism in dual-porosity soils during the installation of in situ biobarrier. To investigate the effect of dual-porosity on transport and biodegradation of organic hydrocarbons, a bimodal approach was incorporated into the model. Modified Monod kinetics and a microcolony concept were employed to represent the effects of biodegrading microbes on the transport and biodegradation of an organic contaminant. The effect of permeability reduction in biobarrier due to biomass accumulation on the flow field were examined in the simulation of a hypothetical field-scale in situ bioaugmentation. Simulation results indicate that the presence of the immobile region can decrease the bioavailability of biodegradable contaminants and that the placement of microbes and nutrients injection wells should be considered for an effective installation of biobarrier during in situ bioaugmentation scheme.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.12 no.2
• /
• pp.229-237
• /
• 1992

Series system reliability analysis of non-reactive contaminant transport is performed in a two dimensional horizontal domain with two different limit state functions: (1) concentration threshold and (2) exposure time threshold. The transient source transport model is combined with the system reliability model to evaluate the probability that a specified maximum concentration at a node of interest would be exceeded or that a moderate concentration would exceed some exposure limit over a given period of time. The results give probabilities of exceedence greater than probability of each component and they tend to be dominanted by the component with larger probability. Transverse dispersivity turns out to be an important parameter in addition to hydraulic conductivity in a two-dimensional contaminant transport model with transient source. System sensitivity is found to reflect the corresponding sensitivity of both components, with the component with larger probability having a greater influence.

• Wind and Structures
• /
• v.3 no.1
• /
• pp.11-21
• /
• 2000

This paper presents results of modeling of the passive contaminant diffusion from a continuous line finite-size source located on the underlying surface of a neutral near-ground atmospheric layer obtained by using the non-local two-parameteric turbulence model and the transport equation of mean concentration. In the proposed diffusion model the turbulent diffusion coefficient changes not only with the vertical coordinate but also with the distance downstream from the source according to the experimental data. The results of the modeling reproduce structural features of the concentration field.

• Journal of Korea Water Resources Association
• /
• v.35 no.3
• /
• pp.261-274
• /
• 2002

The purpose of this study was to develop two dimensional contaminant transport numerical model by finite element method. The developed model system was tested for water quality analysis when contaminants from tributaries and sewage treatment Plants flow into the main river. In this study, the model was to perform calibration for reasonable parameter production and verification for reliability and accuracy. And, the proposed model was applied on the downstream of Han river using calibrated parameters. These results represented real con taminant distribution profile along the channel, and produced the good agreement in comparing calculated vague with measured value.

• Journal of Radiation Protection and Research
• /
• v.27 no.1
• /
• pp.67-75
• /
• 2002

The groundwater flow and contaminant transport numerical models have been established for understanding the movement of pollutants in surface soil environment. The numerical solutions were compared with the analytic solutions for the verification and the application of the models. The numerical solutions from the groundwater and transport models agreed welt with analytic solutions. Especially, the results of groundwater flow model were validated in one- and two-dimensional heterogeneous media. Therefore, it will represent well the characteristics of the heterogeneous media in the field applications. Also, the phenomena of the pollutant dispersion represented quite well by the advection and the hydrodynamic dispersion in the results of the transport model. The important input factor is the choice of complicated boundary conditions in operating the numerical models. The numerical results are influenced by the choice of the proper boundary conditions.

• Journal of Environmental Science International
• /
• v.5 no.4
• /
• pp.495-511
• /
• 1996

The quantitative study of the groundwater contamination in a porous media is a difficult task. For complex problems, numerical solutions are the most effective means to study the movement of contaminants in the groundwater, The solute transport model used in this study has proved to be an efficient tool to model contaminant transport for complex problems. The model demonstrates its effectiveness in reproducing the coniamination by ihlorides of the groundwater at the landfill site due to leachath from the wastes. It describes the two dimentional solute transport and alteration of the water quality and forecasts the contamination for different management alternatives of the landfill. The model also indicates how the groundwater contamination can be contained within the lower site if a barrier is constructed downstream of the disposed wastes.

• Journal of Korea Water Resources Association
• /
• v.39 no.6 s.167
• /
• pp.511-520
• /
• 2006

Riverbank filtration is a natural process, using alluvial aquifers to remove contaminants and pathogens in river water for the production of drinking water. In Korea, most of the drinking water is supplied by surface water in-take. However, maintaining the quality of the drinking water becomes more and more difficult due to the increase of contamination. In riverbank filtration, the understanding of contaminant transport is an important task for the production of high quality drinking water and for the maintenance of facilities. In this paper, the transport behavior of hydrophobic organic contaminants is investigated when contaminants coexist with dissolved organic matter (DOM) and bacteria. In the developed model, the aquifer is thought of as a four phase system: two mobile colloidal phases, an aqueous phase, and a stationary solid matrix phase. The model equations are solved numerically for various situations. Results indicate that the presence of colloidal matters can enhance the mobility of contaminant significantly and that partitioning coefficients play an important role in the process.

• Journal of Korea Soil Environment Society
• /
• v.3 no.3
• /
• pp.3-10
• /
• 1998

Acid/Base buffer capacity of soil is very important in prediction of contaminant transport for its direct impact on pH change of the system composed of soil-contaminant-water, In this research, diffuse double layer theory as well as two layer electrostatic adsorption model are applied to develop a theoretical model of buffer capacity of soil. Model application procedures are presented as well. Buffer capacity of Georgia kaolinite and Milwhite kaolinite was measured by acid-base titration. Model prediction and experimental results are compared.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.99-101
• /
• 2003

Unsaturated hydraulic conductivity models have been widely used for the numerical modeling of water flow and contaminant transport in soils. In this study, a simple hydraulic conductivity model is developed by using information of particle-size distribution from the lognormal distribution model and its results are compared with those from the Kosugi-Mualem (KM) model. The accuracy of the proposed model is verified for observed data chosen from the international UNSODA database. Results showed that the proposed model produces adequate predictions of hydraulic conductivities. Performance of this model is generally better than the KM function.