• Journal of Environmental Health Sciences
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• v.10 no.2
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• pp.41-51
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• 1984

This study was performed using samples collected at Myungryundong and at Reservoirs. The purpose of this study was to investigate the differences of water quality between tap and raw water, and to analyse drinking water quality by Fe, Zn from corroded galvanized steel pipe. Results were as follows 1. The older the pipe was, the higher the concentration of Ferrum and Zinc was (t-test : p<0.05). Ferrum and Zinc also exceeded the limits in the older galvanized steel pipe. I think that this comes from the corrosion of pipe. 2. Mercury, Arsenic, Cadmium, Lead, Chomium, Argentum and Aurum not detected in raw water were not detected in tap water. Cobalt, Bismuth and Molybudenum detected in raw water were not detected in tap water. I think that this comes from the quality of raw water, the result of water treatment and the improbability of detection of above metals in water delivery system. 3. Silicon measured 2.4698ppm in raw water, but it ranged from 0.4769ppm to 1.982 ppm in tap water. Manganese measured 0.0638ppm in raw water, but it ranged from 0.0026ppm to 0.0198ppm in 17cases(31%) out of 55samples in tap water. I think that this comes from the water treatment. 4. Aluminium not detected in raw water was found in 17 cases (31%) out of the samples (55cases). It may be considered as the use of coagulants $Al_2(SO_4)_3$. $18H_2O$ and PAC (Poly Aluminium Chloride). The concentration of copper in tap water was much higher in 2 cases(3.6%) out of the samples(55) than that of copper in raw water. I think that this may come from the use of ${CuSO}_4$, the preventive of algae growth, and the result of chlorination, but further study must be necoessary to support the proof.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.171.2-171.2
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• 2010

Geothermal effects on the underground water conveyance pipe system have been investigated through the multiregional water supply system from Paldang water intake station. To make an investigation of raw water thermal energy, temperature sensors are installed the surface of the pipes of metropolitan area water supply system. In 2009 winter and early spring seasons, the monthly averaged temperatures at Paldang 2 intake stations are $1.94^{\circ}C$ in February, $4.96^{\circ}C$ in March, and $10.56^{\circ}C$ in April. After the transfer in 26.0 km distance of tunnel and buried pipe, the raw water temperatures are raised to $3.13^{\circ}C$, $6.04^{\circ}C$, and $11.39^{\circ}C$ respectively. As the temperature difference between the raw water and the air reduces, the temperature increasement is reduced by $1.19^{\circ}C$ in Feb., $1.08^{\circ}C$ in Mar., and $0.83^{\circ}C$ in Apr. Since the flowrate is over 1,150,000 $m^3$/day, it is estimated that the water exchanges a huge amount of heat over 1.0 Tcal a day with the ground.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.170.2-170.2
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• 2010

The amount of the heating and cooling energy of water source heat pump using the raw water from the Paldang water intake station is investigated in the study. The Han river water is conveyed in the large-size shallowly buried pipe. Averaged water temperature at the position, 27 km from the Paldang water intake station, is increased by $1.11^{\circ}C$ due to the geothermal energy transfer under the ground, therefore the raw water has more thermal energy than the river water. To estimate of the thermal energy for the raw water, it is assumed that the water source heat pump is used for the heating and cooling ventilation. When $5.0^{\circ}C$ temperature difference energy of the raw water is used in the heat pump system all the year except for the January and February in which $3.0^{\circ}C$ temperature difference energy is used. It is predicted that total 5,766.3 Tcal could be used in the metropolitan area a year, which is about 3.0% of the river water unutilized energy resources.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.615-623
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• 2012

In this study, we evaluate the corrosion indexes (CI) such as Langelier Index (LI), Larson ratio (LR), Ryznar saturation index (RSI), Aggressiveness index (AI) of water quality for raw water, treated water and water in distribution reservoir at major eight drinking water treatment plants (DWTPs) in Korea. By analyzing secondary contamination of tap water, the variation of secondary contaminants was investigated with regard to pipe materials, aging and corrosion index (CI). In addition, we suggested an appropriate CI applicable water quality and the management plan for CI monitoriing. All CI showed corrosive water quality, and they did not change significantly in the distribution network. However, Copper (Cu), iron (Fe) and zinc (Zn) concentrations as secondary contaminants increased through the distribution network. Among CI, LI was most sensitive to changes in raw water quality and drinking water treatment. Also, it has high correlations with other indexes such as RSI, AI. Therefore, LI is considered as an appropriate CI to the domestic water quality. Based on these result, we propose LI as a drinking water quality standard to control the pipe corrosion from DWTPs.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.36-44
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• 1994

A study was carried out in order to investigate the removal efficiencies and removal characteristics of heaw metals such as Pb, Cd, Cr, Cu in raw water by one of conventional water treatment processes. The coagulants used in this study were Alum and PAC. Three kinds of water samples were provided: kaolin water, kaolin water mixed with humic acid and raw water from Han River mixed with suspended matter deposited on raw water inlet pipe. Heaw metals were added to the water samples with their respective turbidity, and jar tests were performed. In the results from heaw metal removal studies, lead might be adsorbed or exchanged on the particle surface (SS) rather than react with organic matter added. Cadmium was affected on the dissolved organic matter. Chromium was affected by the both dissolved organic matter and SS concentration, and the restabilization and the enmeshment appeared at moderate (50~80 NTU) and high (100 NTU) turbidity as defined in this experimenL The removal efficiency of copper was relatively little affected by the dissolved organic matter but by SS concentration in comparison with other heavy metals. In these studies as to the raw water turbidities and concentration of heaw metals, it is proved out that the removal efficiency on heaw metals in both cases of PAC and Alum as coagulants was not significantly different.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.313-320
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• 2013

Biofilm formed on stainless and copper in water treatment plant was investigated for sixteen weeks. Biofilm reactor was specially designed for this study. It was similar to that of a real distribution pipe. Raw water, coagulated, settled, filtered and treated water were used in this study. The average number of heterotrophic bacteria counts was $1.6{\times}10^4CFU/ml$, $5.8{\times}10^3CFU/ml$, $1.8{\times}10^3CFU/ml$, $1.3{\times}10^2CFU/ml$, 1 CFU/ml, respectively. Density of biofilm bacteria formed on stainless and copper pipes in raw, coagulated and settled water increased above $2.9{\times}10^3CFU/cm^2$ within second weeks while more biofilm bacteria counts were found on the stainless pipe than on the copper pipe. In case of filtered water (free residue chlorine 0.44 mg/L), there was no significant difference in the number of biofilm bacteria on both pipes and biofilm bacteria below $18CFU/cm^2$ were detected on both pipe materials after fifth weeks. Biofilm bacteria were not detected on both pipe materials in treated water (free residue chlorine 0.88 mg/L). According to the results of DGGE analysis, Sphingomonadacae was a dominant species of biofilm bacteria formed on the stainless pipe while the copper pipe had Bradyrhizobiaceae and Sphingomonadaceae as dominant bands. In case of filtered water, a few bands (similar to Propionibacterium sp., Sphingomonas sp., Escherichia sp., and etc.) that have 16S rRNA sequences were detected in biofilm bacteria formed on both pipes after fifth weeks. Stainless pipe had higher species richness and diversity than the copper pipe.

• Journal of computational fluids engineering
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• v.7 no.2
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• pp.1-7
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• 2002

The present study is developed device that effectively mixes raw water and chemicals by using the residual head of fluid in the front pipe of flocculation basin, and performed non-dimensional analysis and presented design standard to apply to water plants that have different equipment capacity. The variables for design are a proper ratio between an outer diameter of deflector and a diameter of pipe, a distance between deflector and orifice and a determination of orifice diameter for an optimal mixing. Numerical study has analyzed flow field on a basis of turbulent intensity in an orifice downstream. As Reynolds number of In-Line Orifice was increased from identical design variable, the turbulent intensity of pipe center was no changed almost.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.3
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• pp.394-403
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• 2008

The effects of water injection (WI) and urea injection for NOx on a 4-cylinder Direct Injection (DI) diesel engine were investigated experimentally. For water injection, it was installed at the intake pipe and the water quantity was controlled at the intake manifold and Manifold Air Flow (MAF) temperatures while the urea injection was located at the exhaust pipe and the urea quantity was controlled by NOx quantity and MAF. The effects of WI system, urea-SCR system and the combined system were investigated with and without exhaust gas recirculation (EGR). Several experiments were performed to characterize the urea-SCR system, using engine operating points of varying raw NOx emissions. The results of the Stoichiometric Urea Flow (SUF) and NOx map were obtained. In addition, NOx results were illustrated according to the engine speed and load. It is concluded that the NOx reduction effects of the combined system without the EGR were better than those with the EGR-based engine.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.701-708
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• 2008

As a countermeasure for reduction of corrosion in the delivery and distribution pipes used for tap water, materials for the pipelines in-houses and the effect of water quality on corrosivity of water pipelines were investigated in the distribution system of Han river. As the corrosion index at 6 water purification facilities of Han river, average Langelier Saturation Index (LI) of raw and finished water were -1.0 and -1.4 respectively and average Larson Index (LR) were 9.5 and 9.9, respectively. And also corrosion potential showed corrosivity in finished water (-431~-462 mV) as well as raw water (-426~-447 mV). This results indicate that tap water quality of han river have corrosivity. To understand the corrosivity effect in pipe material used for premise distribution system, water quality of stagnant tap water and tap water were analyzed and the differences between them were calculated. The difference concentration of iron, copper and zinc were $12.9{\mu}g/L$, $31.0{\mu}g/L$ and $45.0{\mu}g/L$ respectively in galvanized steel pipe for use more than 15 years and showed highest concentration. As a result, the control to corrosivity in the water pipelines, corrosivity control treatment in the water purification system can be applied. In advance it is necessary to monitor corrosivity of water quality using corrosive index because corrosivity may differ from the seasonal and regional characteristics and water chemicals dosage. For the future the guideline for corrosion index have to be established.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.349-359
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• 2017

During the past 25 years, in the context of probabilistic safety assessment, efforts have been directed towards establishment of comprehensive pipe failure event databases as a foundation for exploratory research to better understand how to effectively organize a piping reliability analysis task. The focused pipe failure database development efforts have progressed well with the development of piping reliability analysis frameworks that utilize the full body of service experience data, fracture mechanics analysis insights, expert elicitation results that are rolled into an integrated and risk-informed approach to the estimation of piping reliability parameters with full recognition of the embedded uncertainties. The discussion in this paper builds on a major collection of operating experience data (more than 11,000 pipe failure records) and the associated lessons learned from data analysis and data applications spanning three decades. The piping reliability analysis lessons learned have been obtained from the derivation of pipe leak and rupture frequencies for corrosion resistant piping in a raw water environment, loss-of-coolant-accident frequencies given degradation mitigation, high-energy pipe break analysis, moderate-energy pipe break analysis, and numerous plant-specific applications of a statistical piping reliability model framework. Conclusions are presented regarding the feasibility of determining and incorporating aging effects into probabilistic safety assessment models.