• 상하수도학회지
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• 제25권4호
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• pp.547-554
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• 2011

In small-scale water systems, the measurement of quality of raw water in running water is generally implemented when the quality of water is stable and frequency of measurement is low. However, units such as water temperature and pH, which are easily monitored, are frequently measured. In establishing an improvement plan for a water treatment system, the range of concentration of the target material present in the raw water of the running water provides relevant information. If the concentration of target material can be specified by the quality of water of data items that are measured daily, inverse estimation of the range of concentration is possible as well. In this paper, we took note of manganese in the raw water from Ogasawara-mura, Tokyo, and estimated the manganese concentration in the raw water of the running water for the past five years. Based on the results obtained, we have proposed a manganese removal system, considering the current situation and geographical conditions of Ogasawara-mura.

• 한국환경과학회지
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• 제24권7호
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• pp.907-915
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• 2015

The tap water is generally known to be corrosive in the pH range at 6.5 ~ 7.5. And the degree of corrosion varies depending on the types of raw water such as river surface water or lake water of the dam. Although several corrosion index represents the corrosivity of tap water, the typical corrosion indexes such as Langelier saturation index (LI) and calcium carbonate precipitation potential (CCPP) were calculated to monitoring the corrosive water quality about raw and tap water in water distribution system. To control the corrosive water quality, the correlation between corrosion index and water quality factors were examined. In this study, corrosion index (LI, CCPP) and the pH was found to be most highly correlated.

• 한국환경보건학회지
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• 제10권2호
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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.

• 상하수도학회지
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• 제18권2호
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• pp.191-200
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• 2004

DAF process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when the freshwater blooms occut or raw water turbidity become high. Pre-sedimentation iS prepared in case when raw water turbidity is very high by rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while it is difficult to remove in sedimentation. One of the main concerns in adoption of DAF (Dissolved Air-Flotation) process is a high raw water turbidity problem. That is, DAF is not adequate for raw water, which is more turbid than 100NTU. In order to avoid this problem, pre-sedimentation basins are prepared in DAF plant to decrease the turbidity of DAF influent. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, DAF process coupled with sedimentation is suggested that pre-sedimentation with optimum coagulation prior to DAF would be appropriate.

• 상하수도학회지
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• 제34권4호
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• pp.239-250
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• 2020

In this study, effects of five raw water quality parameters (turbidity, odor compounds caused by algae, filter clogging caused by algae, pH increase caused by algae, and organic matter) on improvements and operations costs of typical water treatment plant (WTP) were estimated. The raw water quality parameters were assumed the worst possible conditions based on the past data and costs were subsequently estimated. Results showed that new water treatment facilities were needed, such as a selective intake system, an advanced water treatment processes, a dual media filter, a carbonation facility, and a re-chlorination facility depending on water quality. Furthermore, changes needed to be made in WTP operations, such as adding powered activated carbon, increasing the injection of chlorine, adding coagulation aid, increasing the discharge of backwashed water, and increasing the operation time of dewatering facilities. Such findings showed that to reliably produce high-quality tap water and reduce water treatment costs, continuous improvements to the quality of water sources are needed.

• 상하수도학회지
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• 제13권1호
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• pp.81-94
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• 1999

This study aims at a proposal of the plan that can improve raw water quality by an experimental study using influent water of Nak-dong river, which has been used as raw water for drinking in U-city, through the establishment of the submerged biofilter process PILOT PLANT of media packing channel method. From the analysis of removal efficiency for each water quality item of the collected sample, following results are obtained. First of all, the removal rate of suspended material, BOD, COD, T-N, TOC, turbidity, and $NH_3$ -N appear 82%, 78%, 42%, 15%, 57%, 43%, 54%, and 55% respectively and it is known that the submerged biofilter process of media packing channel method takes effects on water quality improvement from the above analysis results of water treatment efficiency. And the analyzed results for water temperature, residence time, and activities of microorganism, which can be the factors affect on water quality improvement, are as follows. 1) The removal rate variation of SS, BOD, and COD attendant on water temperature change is examined and it is known that the removal rate increases at $13^{\circ}C$ or above. 2) The removal rate of SS, BOD, and COD attendant on residence time is most active in the range of 0~18hr, 0~1.8hr, 0~2.7hr respectively, so it is found that the removal rate becomes smaller after 2.7hr. 3) From the examination of microorganism activity with the abundance of normal bacteria, it is found that the floating bacteria decrease as the flow distance from raw water inflow point of PILOT PLANT increases, and the adhesive bacteria have no concern with the flow distance. And it its known that the biomass of fine algae decreases as the flow distance from the raw water inflow point of PILOT PLANT increases from the examination with Chl-a.

• 한국식품조리과학회지
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• 제20권6호
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• pp.684-694
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• 2004

The purpose of this study was to estimate the microbial and physicochemical quality of some raw vegetables and suggest safer methods of sanitization and storage for foodservice operations. Three sanitization methods were utilized during pre-preparation (tap water, chlorine water and electrolyzed water). Leek and Chicory were monitored as ingredient, with different storage temperatures $(3,\;10^{\circ}C)$ and periods (1, 2, 3, 4 and 7 days). The largest reduction in the microbial counts was shown with the electrolyzed water and for the case before immersion in chlorine water, performing a first washing was more effective in reducing the microbial counts than with no washing. The results showed that the storage temperature, pH, moisture content and microbial loads were important factors affecting the quality of vegetables.

• 한국물환경학회지
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• 제29권3호
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• pp.409-419
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• 2013

In this study, the analytical method for 27 residual pharmaceuticals in raw water was developed. Online sample preconcentration/extraction and analysis with high resolution Orbitrap mass spectrometry (LC-ESI/Orbitrap MS) were performed. The calibration curves showed good linearities (above $r^2$ = 0.998) in the range of 5 ~ 1,000 ng/L. The method detection limit and the limit of quantification were 1.1 ~ 10.0 ng/L and 3.4 ~ 31.7 ng/L, respectively. Recoveries of the target compounds were between 70.1% and 115.8% (except cefadroxil, cefradine, vancomycin, and iopromide (50.2 ~ 67.0%)). The optimized analytical method can be useful to determine the residual pharmaceuticals in raw water.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.48-55
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• 2024

The safety-related raw water system's strong operational condition supports the radiation defense and biological shield of nuclear plant containment structures. Gaps and failures in maintaining proper working condition of main equipment like pump were among the most common causes of unavailability of safety related raw water systems. We integrated the advanced data analytics tools to evaluate the maintenance records of water systems and gave special consideration to deficiencies related to pump. We utilized maintenance data over a three-and-a-half-year period to produce metrics like MTBF, MTTF, MTTR, and failure rate. The visual analytic platform using tableau identified the efficacy of maintenance & deficiency in the safety raw water systems. When the number of water quality violation was compared to the other O&M deficiencies, it was discovered that water quality violations account for roughly 15% of the system's deficiencies. The pumps were substantial contributors to the deficit. Pump availability was predicted and optimized with real time data using response surface method. The prediction model was significant with r-squared value of 0.98. This prediction model can be used to predict forth coming pump failures in nuclear plant.

• 한국물환경학회지
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• 제25권2호
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• pp.205-211
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• 2009

In this study, the membrane filter method was compared to the MPN method for the analysis of total coliforms from raw water using raw test waters and controls including 6 standard strains of coliforms, and the various factors were analyzed on the detection of general and fecal origin coliforms. The range of error rate for the detection of 5 standard strains using the membrane filter and the MPN methods was 0 to 6% and 45 to 133%, respectively. The error rate of the membrane filter method was lower than that of the MPN method. The membrane filter method (m-Endo) showed 10% (11 out of 111) of difference for the detection sensitivity of coliforms isolated from raw water compared to the MPN method (BGLB). The membrane filter method was less affected by the factors including temperature, turbidity, charcoals of powder form, contamination, and reverse pressure. In conclusion, the membrane filter method is a better method for the analysis of total coliforms from raw water than the MPN method, considering the accuracy of detection and the tolerance to various experimental factors.