• 한국환경보건학회지
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• 제29권1호
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• pp.8-15
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• 2003

In this study, chlorine dose at water storage tank was predicted to meet the recommended guideline for free chlorine residual in drinking water distribution system, using EPANET which is a computer program that performs extended Period simulation of hydraulic and water quality behavior within pressurized pipe networks. The results may be summarized as follows. The decay of chlorine residual by season varied considerably in the following order; in summer ($25^{\circ}C$) > spring and fall (15$^{\circ}C$) > winter (5$^{\circ}C$). For re-chlorination at water storage tank by season, season-varying chlorine dose was required at its maximum of 1.00 mg/l in summer and minimum of 0.40 mg/l in winter as free chlorine residual. The decay of chlorine residual through out the networks increased with water age spent by a parcel of water in the network except for some points with low water demand. In conclusion, the season-varying chlorine dose as well as the monitoring of water quality parameters at the some points which showed high decay of chlorine residual may be necessary to deliver the safe drinking water.

• 상하수도학회지
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• 제20권2호
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• pp.281-287
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• 2006

Maintaining adequate chlorine residual is crucial in water treatment facilities, Treatment technique, newly promulgated regulation, requires sufficient disinfection in order to control more resistant microorganisms such as Viruses and Giardia lamblia. Each water treatment plant should report various water qualities including chlorine residual and disinfection by-products, thus plenty of data has been generated. Even though statistical analysis using these data are forced to investigate the status and effect of water qualities in water facilities very few researches have been performed in korea. This study performed statistical analysis of chlorine residual during three years in Korean drinking water. The average chlorine residual concentrations were 0.701mg/L, 0.738mg/L, 0.763mg/L in 2002, 2003, 2004, respectively. Monthly variations of chlorine residual was not significant. ANOVA result showed that yearly variance of chlorine residual is different in only less than $5000m^3/day$ of water treatment capacity. The statistical analysis can help government to establish new regulation with scientific basis.

• 상하수도학회지
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• 제14권1호
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• pp.108-116
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• 2000

Chlorine is widely used as a disinfectant in drinking-water systems throughout the world. Chlorine residual was used as an indicator for prediction of water quality in water distribution systems. The variation of chlorine residual in drinking water distribution systems of Suwon city was simulated using EPANET. EPANET is a computerized simulation model which predicts the dynamic hydraulic and water quality behavior within a water distribution system operating over an extended time period. Sampling and analysis were performed to calibrated the computer model in 1999 (Aug. Summer). Water quality variables used in simulations are temperature, roughness coefficient, pipe diameter, pipe length, water demand, velocity and so on. Extended water residence time affected water quality due to the extended reaction time in some areas. All area showed the higher concentration of chlorine residual than 0.2mg/l(standard). So it can be concluded that any area in Suwon city is not in biological regrowth problem. Rechlorination turned out to be an useful method for uniform concentration of free chlorine residual in distribution system. The cost of disinfectant could be saved remarkably by cutting down the initial chlorine concentration to the level which guarantees minimum concentration (0.2mg/l) throughout the distribution system.

• 한국수자원학회논문집
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• 제55권spc1호
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• pp.1197-1210
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• 2022

최근 국내에서는 관로 노후화 및 다양한 수질사고 발생으로 인해 상수도 분야에 대한 관심이 급증함에 따라, 상수도 서비스에 대한 이용자들의 수질민원 또한 증가하고 있다. 수질민원의 경우 실제 수질오염뿐만 아니라 소독을 위한 잔류염소농도에 대한 불편을 포함하고 있으며, 따라서 사용자에게 공급되는 잔류염소농도를 균등하게 유지하기 위해 재염소 처리와 같은 다양한 노력이 시도되고 있다. 본 연구에서는 상수관망 내 잔류염소농도 모의를 위해 적용 대상지역의 수질반응계수를 추정하였으며, 수질기준을 만족시키는 동시에 잔류염소농도 균등화를 고려하기 위한 염소 투입 및 재투입 최적화 방법을 제안하였다. 제안된 방법은 국내 대규모 지방상수도를 대상으로 적용하였으며, 격자탐색법을 통해 다양한 염소 투입/재투입 계획을 비교 분석하고, 공급 잔류염소농도의 적합성 및 균등성을 중심으로 최적화한 결과를 제시하였다.

• 한국물환경학회지
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• 제38권6호
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• pp.275-281
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• 2022

To maintain water quality after water treatment, monitoring whether the quality of treated tap water quality changes is essential. However, current investigations are insufficient to prevent secondary contamination in drinking water supply systems. This study investigated Gyeonggi's e apartment where a red water problem occurred and monitored the water quality and corrosiveness of the overall water supply system to the apartment from June 2021 to April 2022. In a comparison of drinking water quality after water treatment and the influent of the reservoir, turbidity and heavy metal concentrations were increased and residual chlorine was decreased due to increases in temperature. Correlation analysis and principal component analysis (PCA) indicated that a low level of residual chlorine may cause the abscission of Mn²⁺ and Fe²⁺ through microorganism activation, which also causes a high level of turbidity. The corrosion index (LI) in the influent of the reservoir tank was increased due to Ca²⁺ and temperature. These results indicate that the corrosiveness of drinking water and the deterioration of drinking water quality were mainly increased between the drinking water treatment plant and the reservoir tank's influent. The findings provide clear evidence that it is essential to manage water supply systems and reservoir tanks to prevent the secondary contamination of drinking water.

• 한국환경과학회지
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• 제11권7호
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• pp.721-727
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• 2002

The characteristics of drinking groundwater quality at Chung Cheong Nam Do was analyzed by investigating the 3,086 groundwater data which were carried out the water quality inspection from Jan. 1998 to Dec. 1998. It was found that all the mean concentration of items was not over the drinking water quality standard except Zn at Yeongee area. The highest mean concentration of nitrate was $8.2 mg/{\ell}$ at Hongsung area. And the mean concentrations of nitrate and ammonium at Sucheon, Yesan, Yeongee were relatively higher. It was considered that the groundwater of that area was contaminated by breeding livestock as farm pollutants. The mean concentrations of chloride, hardness and evaporation residual at coastal regions were higher than inland regions. Especially the mean concentration of chloride was 2.5 times higher. It was considered that the groundwater at coastal regions was affected by seawater. It was found that the correlation between Fe and Mn was relatively high(r=0.776) and the correlation between hardness and evaporation residual was very high(r=0.983). The rainfall series and detection rate of E-coli had the hydrologic persistence. The correlation between the detection rate and rainfall series over 150 mm was very high (r=0.9146). Therefore it is surely required to control the groundwater sanitation in the rainy season.

• 상하수도학회지
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• 제29권2호
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• pp.155-163
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• 2015

Many advanced treatment processes have been introduced to WTPs, however, the consumer confidence on tap water is still low and the percentage of drinking water directly from the tap is less than 2 %. One of the methods to improve the credibility of tap water is to introduce a drinking water certification system. By introducing the system, water treatment processes can be optimized, which in turn, can significantly improve drinking water quality. In this paper, 6 water quality parameters(i.e., turbidity, CT, residual chlorine, geosmin, 2-MIB, Mn) which have significant influences on tap water quality and consumer confidence were identified, and their recommended guidelines were proposed. 3-Star or 5-Star certification can be awarded to the WTPs which have met the certification criteria. The drinking water certification system can be carried out as a voluntary program among drinking water suppliers.

• 한국물환경학회지
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• 제21권1호
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• pp.52-58
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• 2005

The assessment on characteristics of hydraulic behavior and water quality variations of underground reservoirs of buildings were studied. Firstly, it was thought that underground reservoir capacities($m^3$) of buildings should be not determinated by the uniform and same methods but be estimated on the basis of the dwelling areas on dominated households and their residential characteristics, because these characteristics influence significantly on actual water usages and patterns of buildings. Secondly, it was likely that the average reduction rate of residual chlorine in underground reservoirs were affected from the their capacities, because the average reduction rate of residual chlorine in underground reservoirs under $1,000m^3$ was 43 percent, on the other hand, that rate of underground reservoirs over $1,000m^3$ was 60 percent. Thirdly, through the field investigation, the retention time of drinking water in underground reservoirs were in the range from 0.3 day to 3.9 day. In addition to, the average reduction rate of residual chlorine were depended largely on the retention time of drinking water. When the retention time was under 24 hours, the average reduction rate of residual chlorine was 45 percent, and in case of over 24 hours, was 49 percent. Fourth, water level in underground reservoirs was averagely varied in the range from 0.1 m to 2.65 m at the height of underground reservoirs. If considered actual height of underground reservoirs, 37.6 percent of the height of underground reservoirs was only used. Consequently, the frequency of the inflow and outflow of drinking water in underground reservoir were very increased, and had an effect on the reduction of residual chlorine. Lastly, the investigations on hydraulic structure characteristics of underground reservoirs inside showed the locations of inflow and outflow of drinking water almost were in the opposite direction. And some buildings had several baffles in the middle. Nevertheless, their installations had no beneficial for the improvement of water quality.

• 융합신호처리학회논문지
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• 제7권3호
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• pp.143-148
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• 2006

정수장에서 생산한 수돗물이 수용가까지 안전하게 공급하기 위해서는 관내 및 배수지 등의 공급과정에서 철저한 수질관 리가 필요하다. 그러나 배수지의 수질관리 및 모니터링이 전혀 이루어지지 않고 있다. 최근 정부는 먹는 물에 대한 수질관리기준을 강화하고 있으나, 먹는 물에 대한 수질측정 기반기술은 미국, 일본, 독일 등에 비하여 매우 빈약하다. 특히 수질 검사 및 분석기기의 핵심은 센서이나 이들 센서에 대한 기술이 매우 부족하다. 본 논문에서는 국내 먹는 물 수질관리에 대한 관계 법령 및 규정을 분석하고, 먹는 물 수질측정 기준에 적합한 pH, 전도도, 잔류염소, 탁도 및 수온에 대한 센서 및 측정기기의 최적 성능기준을 제안하고, 대표적인 전극센서인 pH, 전도도 및 잔류염소 센서의 상호간섭 및 영향을 분석한다.

• 환경위생공학
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• 제6권2호
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• pp.33-47
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• 1991

1. Water supply treatment plants personnel could not test the water quality control, because most of them rely on the provincial health laboratories about water quality rely rant test. However, in future, plants have to been provided the facilities and equipment of water quality laboratory. 2. Chlorination methods are 89.5% of liquid chlorine and 10.5% of solid chlorine, and the cost per 1 $\m^{3}$ of chlorination is about 1.30 won which chlorination cost is very cheap as 1/142 of drinking water production cost. Input method of chlorine is 35% of automatic method, 56% of semi-automatic, and 9% of other methods, and this is no problem 3. Residual effects of chlorination, in the case of distilled water as a standardized material and 0.2 ppm of seperated residual chlorine, were continued 32 hours in $0^{\circ}C$, and 25 hour in $20^{\circ}C$, of water temperature and in the case of 0.4 ppm of seperated residual chlorine were continued 47 hours in $0^{\circ}C$ and 23 hours in $20^{\circ}C$. 4. In the case of 4 ppm of seperated residual chlorine, residual effects were continued 23 hours in $5^{\circ}C$, 90 hours in $10^{\circ}C$, 78 hours in $15^{\circ}C$, and 60 hours in $20^{\circ}C$ : by the temper; lure of water, continuing residual effects of chlorination are different, so we have to car for the warm season chlorination in the hider temperature. 5. Chlorination effects of drinking waters in the case of 0.4 ppm of seperated residual chlorine were continued 237 hours in $22^{\circ}C$ water : and in the case of rechlorination as 4 ppm of residual chlorine, continued 71 hours in $22^{\circ}C$ water.