• Journal of Korea Water Resources Association
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• v.46 no.4
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• pp.413-424
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• 2013

The TMDL, the watershed-oriented water quality management policy, was introduced to inhibit the total amount of pollutant loading generation, and to develop the region environmentally friendly. However, despite the implementation of TMDL, the water quality of Nam river downstream has worsened continuously since 2005. Diverse pollution sources such as cities and industrial zone are scattered around the Nam river. Eutrophication are caused due to deterioration of water quality by low velocity. BOD concentrations in the eutrophic waters affected by the incoming BOD and the autochthonous BOD by the production of phytoplankton. In this study, the quantitative relation of incoming BOD and autochthonous BOD was analyzed for water quality management. The influence of autochthonous BOD was analyzed using QUALKO2 and QUAL2E. Considering the effects of Chl.a, BOD concentration from QUALKO2 model simulations is higher than BOD concentration from QUAL2E model. The results of QUALKO2 showed higher correlation with the measured data. Autochthonous BOD needs to be managed to solve the water pollution problem of Nam river downstream, which is looking for ways to reduce Chl.a by using the increase of the dam outflow and the improvement of the water quality from WWTP.

• Environmental Engineering Research
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• v.14 no.1
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• pp.13-18
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• 2009

In this study, specific pollutant releases during the Asian monsoon season were estimated and the information was applied to the non-point pollutant sources management from two forested watersheds of the Soyang Lake. The two watersheds are part of the 2,703 km2 Soyang Lake watershed in the northern region of the Han River. The outlets of the two watersheds were respectively analyzed for continuous water quality concentration and for discharge during various single rainfall events. Statistical power function methods are utilized to compare stream discharge and pollutant flux release during the study period. Based on the monitoring data during the study period, the specific load flux method using simulated discharge was conducted and validated in the two watersheds. The model predictions corresponded well with the measured and calculated pollutant releases. The modeling approach taken in this study was found to be applicable for the two forested watersheds.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.62-70
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• 2005

Step-feed process for biological nitrogen removal were analyzed numerically for the each unit and final total nitrogen(TN) effluent by water quality management(WQM) model and the results were compared data from these wastewater treatment plants. No bugs and logic error were occurred during simulation work. All of the simulation results tried to two times were obtained and both results were almost same as this model has become good reappearance. It was concluded that most of nitrogen removal occurred in the first oxic tank. Thus the controlling of the first anoxic tank may be more important in term of nitrogen removal. Also each unit of simulation result was kept good relationship with that of measured data. Accordingly this WQM model has good reliance. Finally, WQM model can predict final TN effluent within ${\pm}6.0mg/{\ell}$.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.3
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• pp.129-137
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• 2005

In this study, we developed a model to simulate the interaction between sediment and the overlying water. The model deals with water-sediment interaction in terms of the sedimentation of organic detritus from the pelagic zone into the benthic zone and the release of nutrients occurring in the reverse direction. The model was tested and verified by comparing the predicted release rates of phosphorus from the sediment in Osaka Bay with actual observed values. The results accurately reproduced the seasonal change in release rates. The results well represented seasonal change of the release rates. A long-term prediction of water and sediment quality was performed for the period from 1950 to 1999. Nutrient loads from land and the boundary conditions of 3-D baroclinic flows were season-adjusted. The model accurately reproduced the changing trends in phosphorus, nitrogen, and COD concentrations in Osaka Bay over a long period of time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.554-561
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• 2013

In this paper, we introduce a modeling and a process simulator developed with the aid of pRBFNNs for activated sludge process in the sewage treatment system. Activated sludge process(ASP) of sewage treatment system facilities is a process that handles biological treatment reaction and is a very complex system with non-linear characteristics. In this paper, we carry out modeling by using essential ASP factors such as water effluent quality, the manipulated value of various pumps, and water inflow quality, and so on. Intelligent algorithms used for constructing process simulator are developed by considering multi-output polynomial radial basis function Neural Networks(pRBFNNs) as well as Fuzzy C-Means clustering and Particle Swarm Optimization. Here, the apexes of the antecedent gaussian functions of fuzzy rules are decided by C-means clustering algorithm and the apexes of the consequent part of fuzzy rules are learned by using back-propagation based on gradient decent method. Also, the parameters related to the fuzzy model are optimized by means of particle swarm optimization. The coefficients of the consequent polynomial of fuzzy rules and performance index are considered by the Least Square Estimation and Mean Squared Error. The descriptions of developed process simulator architecture and ensuing operation method are handled.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.29-37
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• 2007

Shallow alluvial groundwaters in Korea of tell exceed the Korean Drinking Water Standard for dissolved iron (0.3 mg/L), which is one of the important water quality problems, especially in the use of bank infiltration technique. Using the reactive transport modeling, in this study we simulated the effectiveness of injection-and-pumping technique to remove dissolved iron in groundwater. The results of simulation showed that pumping of groundwater after injection of oxygenated water into aquifers is very effective to acquire the permissible water quality level. Groundwater withdrawal up to several times of irjected water in volume can be applicable to yield drinkable water. Potential problems such as clogging and permeability lowering due to in-situ precipitation of iron hydroxides may be insignificant. We also discuss on the mechanism and spatial extent of iron removal in aquifer.

• Proceedings of the KSRS Conference
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• v.2
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• pp.647-650
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• 2006

Compact Airborne Spectrographic Imager (CASI) hyperspectral imagery was acquired over the Little Miami River Watershed (1756 square miles) in Ohio, U.S.A., which is one of the largest hyperspectral image acquisition. For the development of a 4m-resolution land cover dataset, a hierarchical approach was employed using two different classification algorithms: 'Image Object Segmentation' for level-1 and 'Spectral Angle Mapper' for level-2. This classification scheme was developed to overcome the spectral inseparability of urban and rural features and to deal with radiometric distortions due to cross-track illumination. The land cover class members were lentic, lotic, forest, corn, soybean, wheat, dry herbaceous, grass, urban barren, rural barren, urban/built, and unclassified. The final phase of processing was completed after an extensive Quality Assurance and Quality Control (QA/QC) phase. With respect to the eleven land cover class members, the overall accuracy with a total of 902 reference points was 83.9% at 4m resolution. The dataset is available for public research, and applications of this product will represent an improvement over more commonly utilized data of coarser spatial resolution such as National Land Cover Data (NLCD).

• Magazine of the Korean Society of Agricultural Engineers
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• v.42
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• pp.38-49
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• 2000

Two application rates (9 and 18 t/ha) of poultry litter and a recommended rate of commercial fertilizer were studied to determine their effects on nutrient (N and P) losses in surface and subsurface runoff and loadings in soil layers from conventionally-tilled com by the treatments. The model predicted higher sediment losses than observed data from all treatments. The overpredicted sediment losses resulted in overprediction of organic-N and sediment-P losses in surface runoff. Simulated soluble-P losses in surface runoff were close to observed data, while NO3-N losses in surface runoff were underpredicted from all treatments. Observed NO3-N concentrations in leachate at 1.0-m depth from commercial fertilizer treatment were fairly well predicted. But the concentratins were overpredicted from poultry litter treatments due to high simulation of organic-N mineralization simulated by the model.

• Journal of Korean Society on Water Environment
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• v.29 no.4
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• pp.466-475
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• 2013

Non-point source pollution management is one of the most important issues in Korean water quality/watershed management. In recent years, Low Impact Development (LID) has emerged as an effective approach to control stormwater in an urban area. This study illustrates how to design and evaluate the effect of non-point pollutant management using EPA-SWMM LID module and suggests design parameters for modeling LID facilities. In addition, optimal installation locations of LID can be determined by a simple distributed hydrologic model by using SWMM for a long-term.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.105-110
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• 1999

Unused irrigation water due to delievery losses and management losses. and ground water releases from infiltration in the paddy irrigation system are eventually returned to the stream. They are called as irrigation return flow. It affects the discharge of drought flow in the down strenamflow. And it may contain chemicals, and threaten streamflow quality . Thus, the accurage estimation of irrigation return flow is important to the streamflow modeling and water resources planning , and also to the control of agriculutral nonpoint source pollution . The irrigation return flow of pumped water was investigated in the Keum river watershed.