• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.779-783
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• 2000

• Journal of Korea Water Resources Association
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• v.33 no.S1
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• pp.779-783
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• 2000

• Journal of Korean Society on Water Environment
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• v.31 no.4
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• pp.351-359
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• 2015

The study on the improvement of discharge water quality from domestic wastewater treatment plant (DWTP) was performed in a filter type bioelectrochemical system. The COD removal efficiency for a synthetic discharge water was about 88%, and the effluent COD was less than 5mg/L. The nitrification efficiency of the bioelectrochemical system was over 97%, but a considerable amount of the nitrogen was remained as nitrate form in the effluent. The total nitrogen removal efficiency was only around 30%. There are no significant differences in the removal of COD and nitrogen at 0.6 and 0.8V of the applied voltages between anode and cathode. The removal of COD and nitrogen in the system were quite stable when the HRT ranged from 60 to 15 minutes, and at 10 minutes of HRT, the nitrification efficiency was slightly decreased. The performance of the bioelectrochemical system has quickly recovered from the shocks in the influent due to high concentration of COD and nitrogen. For the effluent that discharged from the DWTP, the removal efficiencies of COD and total nitrogen from the bioelectrochemical system were 50 and 30%, respectively. Thus the bioelectrochemical system was a feasible process for further polishing the effluent quality from DWTP.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.789-797
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• 2006

This study was conducted to establish the refined model for prediction of flocculation/sedimentation efficiency in factual drinking water treatment plants using model tree technique. In order to carry out machine leaning for determining each linear model, five parameters; time, coagulant dose, raw water turbidity, SCD and conductivity, which were measured and collected from the field (K_DWTP), were selected and used. The existing analytical models developed by previous researchers were used only to examine closely the mechanism of flocculation rather than to apply it for practical purpose. The refined model established using model tree technique in this study could predict the factual sedimentation efficiency accurately (below 9% of average absolute error). Also, in aspect of engineering convenience, without any additional manipulation of parameters, it can be applied to practical works.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.3
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• pp.240-250
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• 2000

In this study, DWTP Advisor developed from U.S. EPA was adapted for performance assessment in small water treatment plant and studied for improvement advice about the problem. From results of performance assessment, the ability of each major unit process meets to Peak Instantaneous Flow(PIF) as Type I (above 95% of PIF) in N WTP. But, outlet condition in the sedimentation basin are permitting the loss of solids from the basin and the lack of proper solids removal is degrading the performance in N WTP. From results of the hydraulic analysis using fluoride tracer, flow rate in sedimentation basin is rapidly more lower than upper. The Reynolds number, Re, and Froude number, Fr which are used to predict flow condition in sedimentation basin is calculated to be 3159.98 and $2.06{\times}10^{-7}$, respectively. There is possibility of occurrence of short-circuiting and turbulence. Also, the different type of effluent trough makes unstable flow in sedimentation basin and increases carry-overing of sedimented solids.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.691-700
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• 2006

This study conducted to optimize the design and operation of orifice typed distribution channels which were generally constructed to link the rapid mixing process and flocculation/sedimentation basin. To accomplish the goal of this study, programming step method using FORTRAN 90, was applied it to simulate the performance of existing distribution channel in the selected S DWTP (Drinking Water Treatment Plant). The proposed step method program was validated in terms of the feasibility with comparison between the measurement and prediction value in each orifice. From the evaluation results of the current conditions with the design and operation, it was revealed that the existing gradient of the tapered channel is not appropriate. Also, we suggested that in the case of the inlet width being 3.5m, reducing the downstream width by about 0.5m would make more equitable distribution flow in the channel. Consequently, dealing with various conditions of the design and operation with distribution channel, we could conclude that for the parallel typed channel, as the width is wider and the diameter of orifice is smaller, the more equitable distribution occur. In addition, the inlet flowrate and the number of orifice can affect the flow velocity in the channel.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.389-398
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• 2018

A nationwide survey of 8 N-nitrosamines in finished water samples from drinking water treatment plants (DWTPs) in Korea was conducted. The samples were pre-treated by solid-phase extraction (SPE) and analyzed using a gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). According to the study results, four N-nitrosamines (NDMA, NDEA, NMOR, NDBA) were detected for three consecutive years, NMEA and NPYR were only found in samples collected in 2013. Two of these N-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), have received attention and were the most commonly detected. The concentration of NDMA and NDEA in this study ranged from $0.002{\mu}g/L$ to $0.013{\mu}g/L$ and in $0.001{\mu}g/L$ to $0.008{\mu}g/L$, respectively. In comparison to studies performed in EPA(UCMR2), the concentrations of NDMA (from $0.002{\mu}g/L$ to $0.630{\mu}g/L$) and NDEA (from $0.005{\mu}g/L$ to $0.100{\mu}g/L$) observed in the this study were low.

• Analytical Science and Technology
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• v.17 no.5
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• pp.423-433
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• 2004

This study was examined occurrence of bisphenol A (BPA) and nonylphenol (NP) in waterworks system of Seoul, Korea from September 2002 to December 2003. The levels of BPA and NP in Han-river and its tributaries were as followed: Paldang-dam, ND(not detected)${\sim}0.033{\mu}g/L$ and $ND{\sim}0.823{\mu}g/L$; Kyungahn-creek, $ND{\sim}0.659{\mu}g/L$ and $ND{\sim}3.827{\mu}g/L$; Whangsuk-creek, $ND{\sim}0.528{\mu}g/L$ and $ND{\sim}12.724{\mu}g/L$, respectively. In water of 6 intake-station, the contents of NP and BPA were detected $0.122{\sim}2.724{\mu}g/L$, and $ND{\sim}0.260{\mu}g/L$, respectively. In the finished- and tap-water of three drinking water treatment plants (DWTPs) around Whangsuk-creek, BPA was not detected in all samples, while NP was in ppt levels in whole. Through the process of DWTP, also, the removal ratio of NP was above 80% in all this. Therefore, this result was suggested that levels of BPA and NP in waterworks system depended on non-point contaminants and swage treatment plants in the Han-river shed.