• 산업기술연구
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• 제21권B호
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• pp.11-20
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• 2001

This laboratory study examined the impact of free chlorine residual and pipe material on the formation of biofilm in drinking water distribution pipe surfaces. Result of heterotrophic plate counts(HPC) of the biofilm in the tap water-supplied reactor averaged $2.17{\times}10^5CFU/cm^2$ on PVC and $2.43{\times}10^5CFU/cm^2$ on STS 316, respectively. HPCs on the surface exposed to the tap water containing 0.2mg/L of free chlorinne residual averaged $4.24{\times}10^4CFU/cm^2$ on PVC and $6.54{\times}10^4CFU/cm^2$ on STS 316, respectively. Average of HPC/Total direct counts in the tap water-supplied reactor ranged from 1.08%(PVC) to 1.26%(STS 316) and from 0.38%(PVC) to 0.65%(STS 316) in the reactor supplemented with disinfectant, respectively. No correlation was observed between disinfectant addition and biofilm density. With regard to the biofilm formation, little difference existed between PVC and STS 316. Yellow and red pigmented bacteria were the dominant expressions in bulk fluid, whereas non-pigmented bacteria were found dominant in the biofilm. Pink/red pigmented bacteria were found to be facultative anaerobic, while yellow pigmented bacteria and non-pigmented bacteria were found to be obligate aerobic.

• 대한환경공학회지
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• 제29권6호
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• pp.706-714
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• 2007

본 연구에서는 배급수계통에서 잔류염소와 THMs의 분포를 예측하는 방안을 제시하였다. 잔류염소와 THMs의 등의 수질변화에 대해 현장조사를 실시하였고, 수체와 관벽에 대한 잔류염소 감소계수와 THMs의 생성계수를 산출하여 관망해석에 의한 수질모델링에 적용하였다. 병실험을 통해 잔류염소 병렬 1차 수체 반응계수를 구하고, 5개 관벽 감소 모델을 비교 평가하여 1차 관벽 감소계수 산출하고 적용했을 때 잔류염소 현장 측정값과 관망 수질모델링에 의한 예측간의 평균절대오차 및 평균제곱근오차가 각각 0.03, 0.037 mg/L로 가장 작았다. 또한 병실험에 의한 THMs생성량을 비선형 회귀분석으로 1차 생성계수를 구하고 현장 측정값과 비교하였다. 그 결과, 9월의 현장 측정값과 예측값의 결정계수 $R^2$는 0.98, 11월에는 0.82로 예측이 가능하였다.

• ETRI Journal
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• 제21권3호
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• pp.16-21
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• 1999

After etching Al-Cu alloy films using SiCl4/Cl_2/He/CHF3 mixed gas plasma, the corrosion phenomenon at the grain boundary of the etched surface and a passivation layer on the etched surface with an SF6 plasma treatment subsequent to the etching were studied. In Al-Cu alloy system, corrosion occurs rapidly on the etched surface by residual chlorine atoms, and it occurs dominantly at the grain boundaries rather than the crystalline surfaces. To prevent corrosion, the SF6 gas plasma treatment subsequent to etching was carried out. The passivation layer is composed of fluorine-related compounds on the etched Al-Cu surface after the SF6 treatment, and it suppresses effectively corrosion on the surface as the SF6 treatment pressure increases. Corrosion could be suppressed successfully with the SF6 treatment at a total pressure of 300 mTorr. To investigate the reason why corrosion could be suppressed with the SF6 treatment, behaviors of chlorine and fluorine were studied by various analysis techniques. It was also found that the residual chlorine incorporated at the grain boundary of the etched surface accelerated corrosion and could not be removed after the SF6 plasma treatment.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.47-47
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• 2010

Discharge under the water is very hard and demand considerable high voltage. But specially improved electrode can generate plasma discharge to salty water with relatively low voltage. A round shape ceramic electrode having many pinholes combined with metallic one can generate plasma. 400 volt, 10 kHz and 3 micro second pulse width were applied to repeatedly running synthetic seawater with 10 L/m velocity, containing cultivated E. coli and Bacillus. As a result, 18, 94, 99.97, 100, 100 % disinfection rates to E. coli and 17.1, 17.1, 82.9, 99.4, 99.9 % disinfection rates to Bacillus subtilis were achieved to 1, 2, 3, 4, 5 times repetitive treatment respectively. In the plasma condition, the ions and electrons are separated and new kinds of components are re-synthesized by the intensive movement of the components. Especially chlorine ions are separated and recombined to residual free chlorine like HOCl, $OCl^-$. The residual free chlorine concentrations of discharged water were 0.25, 0.88, 1.39, 1.59, 1.66 mg $Cl_2$/L after 5 times treatment respectively. Another unconfirmed radical and oxidants for example, OH, $H_2O_2$, and $O_3$ can have an effect on microorganism of course.

• 한국식품영양과학회지
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• 제38권5호
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• pp.601-604
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• 2009

본 연구는 이산화염소수 처리가 식품에서의 잔류농약 제거에 효과가 있는지 조사하기 위해서 수행되었다. 10, 50, 100 ppm 이산화염소수로 채소류에 흔히 쓰이는 농약인chlrpyrifos, diazinon, metalaxyl을 처리하여 GC를 이용하여 농약의 분해율을 측정하였다. 상기 세 가지 농약 성분은 이산화염소수 처리 농도뿐만 아니라 처리시간에 비례하여 분해되었으며 특히 100 ppm 이산화염소수 처리가 가장 효과적이었다. 또한, 인위적으로 농약을 오염시킨 상추를 증류수, 100 ppm 이산화염소수에 각각 침지하여 농약의 제거율을 비교해 보았을 때, 100 ppm 이산화염소수에 10분 동안 침지하였을 때가 가장 효과가 좋았다. 본 연구 결과, 이산화염소수 처리는 신선농산물에서의 잔류농약을 제거하기 위한 세척수로 이용될 수 있을 것으로 판단된다.

• 환경위생공학
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• 제4권1호
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• pp.37-42
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• 1989

Management of Swimming pool is focused on Swimming pool samitation in relation with chlorination of swimming water and potable water, disposal of waste and excrement within the boundry of swimming pool that may be summerised as follows: 1. Chlorination of Swimming Water Residual chlorine must be kept within the range of $0.4\~0.6 mg/l$ and in case of chloramine should be $0.7\~1.0mg/l$ while swimming pool is in operation 2. Chlorination of potable Water Residual chlorine must be kept within the rangs of $0.2\~04 mg/l$ at all time 3. Disposal of litters must be kept in the water tight waste bin with fitted lid, and waste should not be overflow -out of the bin. When waste in landfilled, the sufficient amount of cover material should be used daily. 4. Disposal of excrement Toilet must be water-flush type. However, The establishment of pit latrine is unavoidable the excrement must be covered with lime or dirt so that excrement should not be exposed to air.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2000년도 춘계총회 및 학술발표회
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• pp.17-17
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• 2000

• 한국환경보건학회지
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• 제29권3호
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• pp.65-71
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• 2003

The injection concentration of corrosion inhibitor increases under the pH 7, temperature of 2$0^{\circ}C$, and alkalinity of 35 mg/l (as CaCO$_3$), the corrosion rate gradually decreased. When the corrosion inhibitor of 10 mg/l is injected, the corrosion rate for carbon steel pipe, galvanized steel pipe, and copper pipe reduces for 37, 66 and 61 % respectively that it is more efficient on galvanized steel pipe and copper pipe. As a result of examination of corrosion rate at pH 6, 7, and 8 when injecting 10 mg/l of corrosion inhibitor under the conditions of 2$0^{\circ}C$ in water temperature and 35 mg/l (as CaCO$_3$) in alkalinity, the efficiency of the corrosion inhibitor increases as the pH increases. For carbon steel pipe, it does not show much a difference with the change of the pH condition, but galvanized steel pipe and copper pipe clearly show the corrosion rate depending on the change of the pH condition. The efficiency of corrosion inhibitor is low as the concentration of residual chlorine is high, but it does not show a great influence at 0.4 mg/l or less. For each pipe type, in the case of carbon steel pipe, the range of increase of corrosion speed following the residual chloride is higher than the other pipe types. In the meantime, the effect following the residual chlorine in copper pipe is low.

• 한국전자통신학회논문지
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• 제14권4호
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• pp.723-728
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• 2019

우리가 일상적으로 마시는 수돗물의 경우 수질의 오염에 대한 시민들의 불신은 매우 높은 편이다. 또한 수돗물의 수질오염사고는 예측이 어렵고 그 위험이 커서 실시간 모니터링과 관리가 필요하다. 따라서 사물인터넷을 이용한 실시간 수질 모니터링의 도입이 필요한 분야라 할 수 있다. 잔류염소는 다른 소독제보다 잔류성 및 경제성이 우수하고 잔류효과 확인이 쉬워 상수도에서 주로 소독 지표로 활용되는데 수돗물의 안전성을 확보하는 차원에서 사물인터넷기술을 이용하여 실시간으로 감시가 가능하다. 본 연구에서는 전류법 센서를 이용하여 실시간 수질 모니터링을 위한 스마트 디바이스를 개발하고 그 성능을 분석하였다.

• 상하수도학회지
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• 제19권4호
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• pp.487-496
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• 2005

Chlorine bulk decay tests were carried out by bottle test under controlled conditions in a laboratory. Experiments were performed at different temperatures: $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and the water temperatures when samples were taken from the effluent just before entering to its distribution system. 38 bulk tests were performed for water of Al (water treatment plant), 4 bulk tests for A2 (large service reservoir), and A3(pumping station). Residual chlorine concentrations in the amber bottles were measured over time till about 100 hours and bulk decay coefficients were evaluated by assuming first-order, parallel first-order, second-order. and $n^{th}-order$ reaction. The $n^{th}-order$ coefficients were obtained using Fourth-order Runge-Kutta Method. A good-fit by the average coefficient of determination ($R^2$) was first-order ($R^2=0.90$) < parallel first-order ($R^2{_{fast}}=0.92$, $R^2{_{slow}}=0.95$) < second-order ($R^2=0.95$) < $n^{th}-order$ ($R^2=0.99$). But if fast reaction of parallel first-order bulk decay were applied to the effluent of large service reservoir with ca. 20 hours of travel time and slow reaction in the water distribution system following the first 20 hours, parallel first-order bulk decay would be best and easy for application of water quality modeling technique.