• 한국방재안전학회논문집
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• 제9권2호
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• pp.63-75
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• 2016

안전한 수돗물 공급을 위해 정수처리장부터 최종 단계인 수도꼭지까지 일정 수준 이상의 잔류염소농도가 유지되어야 한다. 하지만 국내 문헌에 따르면 상수공급의 전체 과정 중에 30-60%의 잔류염소가 소실되고, 이에 대한 주요 원인으로 정수처리 과정에서 염소 사용량 감소 추세, 급수배관 내에서 염소분해 손실, 여름철의 높은 온도에 의한 잔류염소 분해 속도 증가, 급수배관의 노후화에 따른 잔류염소 손실, 저수조 내 저장 시 잔류염소 감소 발생 등이 파악되었다. 이러한 이유로 저수조를 거치는 급수 방식의 경우 최종 수도꼭지의 잔류염소 농도가 기준치보다 낮아질 개연성이 높고, 용량과 체류시간을 단순히 고려하는 기존의 저수조 설계 방식으로 인해서 수돗물 공급의 안전성에 대한 우려가 존재한다. 이의 개선 방안 도출을 위해서 본 연구에서는 저수조 내 잔류염소 감소에 관여하는 주요 기작들인 수체 내 잔류염소 분해, 벽체 표면 흡착, 그리고 증발에 의한 물질전달을 수학적으로 묘사하는 공식들과 계수 값들을 문헌을 통해서 획득하고, 일반적 저수조 조건에서 모델 시뮬레이션을 수행하였다. 그 결과 저수조에 유입되는 수돗물 내 유기물 농도, 수돗물이 저수조에 유입되는 수리학적조건(난류 정도), 그리고 저수조 벽체 표면 재질의 흡착능 등이 저수조 내 잔류염소 감소에 주요 영향 인자들임을 알 수 있었다. 본 연구에서 획득된 결과들은 잔류염소 감소를 최소화하여 안전한 수돗물 공급을 가능하게 하는 새로운 저수조 설계기법이나 기술 개발에 유용하게 활용될 것이다.

• 한국물환경학회지
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• 제33권2호
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• pp.187-196
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• 2017

To ensure hygienic safety of drinking water in a water storage tank, the concentrations of residual chlorine should be above a certain regulation level. In this study, we conducted model simulations to investigate the effects of temperature on residual chlorine in water storage tank conditions typically used in Seoul. For this, values of model parameters (decomposition rate constant, sorption coefficient, and evaporation mass transfer coefficient) were experimentally determined from laboratory experiments. The model simulations under continuous flow conditions showed that the residual chlorine concentrations were satisfied the water quality standard level (0.1 mg/L) at all the temperature conditions ($5^{\circ}C$, $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$ and $25^{\circ}C$). Meanwhile, when the tanks had a no flow condition (i.e., no tap-water influent due to a sudden shut-down), the concentrations became lower than the regulatory level after certain periods. The findings from this modeling works simulating Seoul's water storage tanks suggested disappearance rate of residual chlorine could be reduced through the tanks design optimization with maintenance of low water temperature, minimization of air flow and volume, suppression of dispersion and the use of wall materials with low sorption ability.

• 대한방사선기술학회지:방사선기술과학
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• 제24권2호
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• pp.53-57
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• 2001

The purpose of this study is to investigate the contamination rate of barium sulfate suspension made in the exposed state in usual circumstances. This study was performed in four university hospital using the contrast media by barium sulfate powder. The specimen were detected at dispensing water, agitator and mixing tank. We also classified the suspension into general bacteria, mycete, and Bacillus coli infection. The tap water were used to dispense water in the all hospitals. Bacillus colt were not detected in the all. General bacteria and mycete were not detected in the one specimen, but detected in two specimen over defined value. In the contamination rate of agitator, mixing tank, and the manufactured, Bacillus coli were not detected in all. However, general bacteria and mycete were detected too numberous to count. In conclusion, the refined water must be used in dispensing water in manufacturing suspension. The disinfectant is also used in washing the agitator and mixing tank for sterilization. Hand washing is indispensible to manufacturing suspension for preventing from infection.

• Parasites, Hosts and Diseases
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• 제51권4호
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• pp.461-466
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• 2013

From May to June 2012, a waterborne outbreak of 124 cases of cryptosporidiosis occurred in the plumbing system of an older high-rise apartment complex in Seoul, Republic of Korea. The residents of this apartment complex had symptoms of watery diarrhea and vomiting. Tap water samples in the apartment complex and its adjacent buildings were collected and tested for 57 parameters under the Korean Drinking Water Standards and for additional 11 microbiological parameters. The microbiological parameters included total colony counts, Clostridium perfringens, Enterococcus, fecal streptococcus, Salmonella, Shigella, Pseudomonas aeruginosa, Cryptosporidium oocysts, Giardia cysts, total culturable virus, and Norovirus. While the tap water samples of the adjacent buildings complied with the Korean Drinking Water Standards for all parameters, fecal bacteria and Cryptosporidium oocysts were detected in the tap water samples of the outbreak apartment complex. It turned out that the agent of the disease was Cryptosporidium parvum. The drinking water was polluted with sewage from a septic tank in the apartment complex. To remove C. parvum oocysts, we conducted physical processes of cleaning the water storage tanks, flushing the indoor pipes, and replacing old pipes with new ones. Finally we restored the clean drinking water to the apartment complex after identification of no oocysts.

• 한국수산과학회지
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• 제21권5호
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• pp.288-291
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• 1988

마비성패류독으로 독화된 진주담치를 시료로 하여 축양 또는 가공방법에 따른 제독실험을 한 결과를 요약하면 다음과 같다. 1. 독화된 진주담치를 순환수조에서 축양하였을 때는 유의할 만한 제독효과는 나타나지 않았으나 유수수조에서 축양한 경우는 5일만에 약 $94\%$가 감소하였다. 2. PSP를 0.1N HCl 용액으로 유출하였을 때가 증류수로 추출하였을 때 보다 그 독성이 약 2-5배 높았다. 3. PSP가 $100\~150{\mu}g/100g$ 정도로 독화된 진주담치를 수도수에서 30분간 자숙하였을 때 그 독성은 동물실험결과 검출되지 않았다. 4. PSP가 $175{\mu}g/100g$ of digestive gland인 진주담치를 $116^{\circ}C$에서 65분간 가압살균하였을 때는 동물 실험결과 독성이 검출되지 않았으나 독소함양이 $9539{\mu}g/100g$ of digestive gland인 고독력의 진주담치는 같은 조건에서 가압살균하여도 $171{\mu}g$의 독력이 잔존하였다.

• 한국수산과학회지
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• 제21권5호
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• pp.297-302
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• 1988

마비성패류독으로 독화된 진주담치를 시료로 하여 축양 또는 가공방법에 따른 제독실험을 한 결과를 요약하면 다음과 같다. 1. 독화된 진주담치를 순환수조에서 축양하였을 때는 유의할 만한 제독효과는 나타나지 않았으나 유수수조에서 축양한 경우는 5일만에 약 $94\%$가 감소하였다. 2. PSP를 0.1N HCl 용액으로 유출하였을 때가 증류수로 추출하였을 때 보다 그 독성이 약 2-5배 높았다. 3. PSP가 $100\~150{\mu}g/100g$ 정도로 독화된 진주담치를 수도수에서 30분간 자숙하였을 때 그 독성은 동물실험결과 검출되지 않았다. 4. PSP가 $175{\mu}g/100g$ of digestive gland인 진주담치를 $116^{\circ}C$에서 65분간 가압살균하였을 때는 동물 실험결과 독성이 검출되지 않았으나 독소함양이 $9539{\mu}g/100g$ of digestive gland인 고독력의 진주담치는 같은 조건에서 가압살균하여도 $171{\mu}g$의 독력이 잔존하였다.

• Journal of Yeungnam Medical Science
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• 제5권1호
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• pp.69-75
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• 1988

대구시내 6개구에서 각 2개소의 아파트와 각 1개소의 단독주책을 선정하여 총 18개소의 가정상수를 1987년 5월 12일에서 10월 15일 사이에 봄, 여름, 가을 3회에 걸쳐 채취하여 이화학적 및 미생물학적 수질검사를 시행하였다. pH치는 최저 6.80에서 최고 8.10으로 모두 정상범위였으며, 잔류염소치 0.2ppm미만인 경우가 아파트군 16.7%, 단독주택군 5.6%였다. 아질산성 질소양성은 아파트군에서만 2.8%로 나타났다. 일반세균수가 $m{\ell}$당 100개 이상인 경우는 아파트군 11.1%, 단독주택군 11.1%였고, 대장균군의 MPN이 1.8%이상인 경우가 아파트군 27.8%, 단독주택군 33.3%였다. 잔류염소치, 아질산성 질소, 일반세균수 및 대장균군 검사에서 4가지 음용기준에 부적당한 것은 아파트군에서만, 2.7%였고, 3가지 검사에서 부적당한 것이 아파트군 2.7% 단독주택군 5.6%, 2가지 검사에서 부적당한 것이 아파트군 8.3% 단독주택군 5.6%, 1가지 검사에서 부적당한 것이 아파트군 25.0% 단독주택군 22.2%였다. 이화학적 및 미생물학적 검사성적의 상호비교에서 잔류염소치와 일반세균수 사이에, 그리고 대장균균수와 일반세균수 사이에 연관성이 있었다. 아파트의 건립년수가 길수록 수질이 좋지 않은 것으로 관찰되었다.

• 한국기계기술학회지
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• 제20권6호
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• pp.917-923
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• 2018

The drinking water supply system applicable to the laying hen consists of air-water heat pumps, drinking water tanks, heat stroage tank, circulation pumps, PE pipes, nipples, and control panels. When the heat pump system has power of 7.7 to 8.7 kW per hour, the performance coefficient is between 3.1 and 3.5. The supply temperature from the heat pump to the heat stroage tank was stabilized at about $12{\pm}1^{\circ}C$, but the return temperature showed a variation of from 8 to $14^{\circ}C$. Stratified temperature in the storage tank appeared at $12.^{\circ}C$, $13.5^{\circ}C$ and $14.4^{\circ}C$, respectively. The drinking water supply temperature remained set at $15^{\circ}C$ and $25^{\circ}C$, and the conventional tap water showed a variation for $23^{\circ}C$ to $30^{\circ}C$. As chickens grow older, the amount of food intake and drinking water increased. $y=-0.0563x^2+4.7383x+8.743$, $R^2=0.98$ and the feed intake showed $y=-0.1013x^2+8.5611x$. In the future, further studies will need to figure out the cooling effect on heat stress of livestock.

• 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.

• Environmental Engineering Research
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• 제18권2호
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• pp.103-108
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• 2013

Vietnam is a developing country with the rate around 5%-6% per year, especially in urban areas. Rapidly developed urban areas lead to stress for infrastructure and the water supply is also stressed. In Hanoi city, total water capacity from the manufactories is around one million cubic meters per day and almost the entire main water source is groundwater but it is not enough to supply all of Hanoi's people, especially in the summer. A demo project is implemented in Hanoi University of Civil Engineering (HUCE) to produce drinking water by using the rainwater and membrane system and supply for people. In this project, rainwater is collected on the rooftop of the lecture building with an area of around $500m^2$ and $100m^3$ volumetric rainwater tanks. Afterwards, the rainwater is treated by the micro-membrane system and supplied to the tap water. Total cost for construction, technology and operation in the first year is around USD 48,558. In the long-term (15 yr) if HUCE invests in the same system, with $20m^3$ volumetric storage tank, it can provide drinking water for 500 staffs in every year. The cost of investment and operation for this system is lower than 30% compared to buying bottled water with the price USD 1.8/bottle. The drinking water parameters after treatment are pH, 7.3-7.75; turbidity, 0.6-0.8 NUT; total dissolved solids, 60-89 mg/L; coliform, 0; heavy metal similar with water quality in the bottle water in Vietnam.