• 상하수도학회지
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• 제23권3호
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• pp.339-344
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• 2009

The authors investigated the bacterial community attached to granular activated carbon(GAC) particles and the susceptibility of the community to chlorine disinfection. The study was carried out at the G Water Treatment Plant in Seoul, which was in full-scale operation. Bacteria attached to the surface of GAC increased gradually with treatment from $0.4{\times}106{\sim}8.5{\times}106 CFU/g$. TOC removal was under 1.0 mg/L due to increased bacterial community on the surface of GAC. It was found that TOC removal was closely related with physical and biological parameters such as pore volume and the number of attached bacteria. When the washed and the attached cells were disinfected with 1.0mg/L of chlorine for 1 hour, the washed cells with chlorination could be controlled, but the number of the attached cells increased gradually. The results suggest a possibility that the treatment and disinfection barriers can be penetrated and pathogenic bacteria may break into the drinking water supplying system.

• 상하수도학회지
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• 제19권3호
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• pp.330-337
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• 2005

This study was carried out to propose the managemental improvement of the purification plants and the distribution facilities which can minimize the formation of disinfection by-products in drinking water distribution system. The disinfection by-products were highly created in the water treatment plant that the organic matters were high and the chlorine dosage was excessive. The concentration of DSPs was shown the highest value in August and the lowest value in December, because of temperature and pre-chlorine dosage effect. From the result of tracer test, the travel time from the treatment plant to the end of pipeline was around 3-4 days in summer, 5-6 days in winter, respectively, and the DSPs concentration of the reservoir(end of pipe) was 2-3 times higher than that of the beginning point. The improvement of the chlorination process and structural reformation of distribution facility was demanded to minimize the DSPs increase from purification plant to the end of pipe.

• 한국물환경학회지
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• 제21권2호
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• pp.176-183
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• 2005

Chlorination of wastewater is recently practiced in Korea. While many researchers have studied the kinetics of aqueous chlorine(HOCl) with nitrogeneous compounds and other organic/inorganic contaminants in drinking water, the researches of wastewater chlorination are relatively few. The purpose of this study was to investigate the chlorine decay kinetics and parameters on wastewater chlorination. Chlorine decay rate increased with increasing initial chlorine concentration. The parameters affecting chlorine decay rate were different in each wastewater treatment plant. One of the most important parameters affecting chlorine decay was initial chlorine concentration, and other parameters such as $NH_3-N$, total coliform, $UV_{254}$ and Fe were also affected. The decay ratio of chlorine was decreased with increasing initial chlorine concentration, and the disinfection efficiency showed good correlation with the decay ratio.

• 대한환경공학회지
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• 제38권2호
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• pp.63-70
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• 2016

수돗물 공급과정에서의 소독부산물 발생현황과 이와 관련된 수질 인자와의 상관성을 조사하여 소독부산물 발생특성을 규명하고자 K-water에서 관리하는 정수장의 수돗물 공급과정 5개 계통에 대하여 조사를 실시하였다. 수돗물 공급과정에서의 공급계통별 Water age 및 노후관 공급계통을 구분하여 조사대상을 선정하였으며, 소독부산물인 트리할로메탄 (THMs) 및 할로아세틱에시드 (HAAs), 유기물 항목으로서 BDOC 및 DOC를 포함하여 7개 항목에 대해 월 1회 조사하였다. 조사결과 노후관계통 및 Water age가 길수록 공급과정 내 유기물 농도가 높아지는 경향성을 확인할 수 있었다. 소독부산물과 관련 영향인자들의 상관관계를 분석한 결과 계통별 잔류염소 감소와 Water age간 상관관계가 매우 높은 것으로 나타났다. 또한 Water age와 THMs 생성간의 결정계수값이 매우 높아 THMs 생성에 Water age가 중요한 인자임을 알 수 있었다. 잔류염소 감소율이 THMs 증가에 미치는 영향 또한 매우 높게 나타났으며, Water age가 길어질수록 수온과 THMs 생성에 미치는 영향은 증가하는 것으로 나타났다. 이와 반면 HAAs는 THMs와는 달리 Water age, 잔류염소, 수온과의 상관관계 조사결과 결정계수 값이 낮게 나타났다.

• 대한환경공학회지
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• 제37권9호
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• pp.505-510
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• 2015

본 연구는 경북 소재 A정수장의 원수를 대상으로 pH, 수온, 염소주입량에 대한 소독부산물(trihalomethanes, haloacetic acids, haloacetonitriles, chloral hydrate 등 16종) 생성능을 조사하고 여과수의 소독부산물 생성능과 비교하였다. 조사한 소독부산물의 생성능은 대부분 중성 pH에서 높았다. 다만, dichloroacetic acid, chloroform, bromodichloromethane의 생성능은 염기성 pH에서 증가하였다. Chloral hydrate, haloacetic acids, haloacetonitriles의 생성능은 수온의 증가와 함께 직선형으로 증가하였고, trihalomethanes의 생성능은 지수함수의 증가추세를 보였다. Chloral hydrate, trihalomethanes, trihaloacetonitriles의 생성능은 염소주입농도 2.0 mg/L $Cl_2$까지 급격하게 상승하였고, 2.0~5.6 mg/L $Cl_2$에서는 완만하게 증가하였다. 여과수의 소독부산물 생성능은 원수에 비해 대부분의 물질에서 낮게 나타났다. 다만, trihalomethanes은 여과수가 원수보다 약 1.4배 높은 생성률을 나타냈다.

• 한국환경과학회지
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• 제11권5호
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• pp.411-418
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• 2002

The current study evaluated the disinfection efficiency of free chlorine and chloramine for microorganisms on various pipe materials, such as copper, galvanized steel, carbon steel, and stainless steel. In addition, the effect of internal pipe corrosion and corrosion inhibitors on the bactericidal efficiency was evaluated using a simulated loop. For disinfection with a phosphate corrosion inhibitor, chloramination was found to be more effective than chlorination due to its persistence. Free chlorine disinfection was optimized with a high phosphoric acid concentration, while chloramine disinfection was optimized with a high phosphoric acid or low polyphosphate concentration. In simulated copper and galvanized steel loop tests, chloramination with phosphoric acid was demonstrated to be more effective.

• 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.

• 한국환경보건학회지
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• 제31권2호
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• pp.147-151
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• 2005

The disinfection effect of free residual chlorine and monochloramine on biofilm communities were investigated by CLPP (community level physiology profile) using Biolog GN plates. Low concentration of disinfectant, $0.5\;mg/\iota$ free chlorine and $1.0\;mg/\iota$ monochloramine, stimulated the growth of bacteria rather than disinfection. Bacterial concentrations were decreased at more than $1.0\;mg/\iota$ of disinfectants. CLPP was different with the type and concentration of disinfectant and sampling time. Common and different carbon sources were actively used with similar bacterial concentration in free chlorine and monochloramine. This represents the differences of bacterial communities with tap water contact times and disinfectant.

• 공업화학
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• 제19권1호
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• pp.122-128
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• 2008

본 연구에서는 J 하수 처리장의 최종 방류수를 대상으로 종속영양세균의 증식과 수중 물리, 화학적 영향인자와의 관계를 고찰하였다. 하수 중의 용존 유기물질 농도는 종속영양세균의 성장과 가장 밀접한 관계를 보였다. 미생물의 영양원인 단백질, 지방, 전분, 섬유소, 팩틴의 분해 세균 분포를 파악한 결과 하수 중 단백질 및 지방세균의 비율은 전체의 81%로 가장 높았다. 종속영양세균은 연중 8월에 가장 높은 수치를 나타냈다. 하수 방류수에 대해 10 mg/L의 유리염소를 주입하여 15 min간 접촉시 THMs의 농도는 $71{\mu}/L$ (< $100{\mu}/L$- 먹는 물 수질기준)의 값을 나타내어 높지 않았다.

• 한국물환경학회지
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• 제21권1호
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• pp.7-13
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• 2005

With the appearance of pathogenic microorganisms, which were resistant to free chlorine, the significant attention to the necessity of powerful alternative disinfection methods such as ozone, chlorine dioxide, LTV irradiation to inactivating pathogens has been increased in water treatment. Among these alternative disinfection methods, ozone is well known as strong biocidal method and the usage of ozone is also increasing in Korea. However, in Korea, there has been no report on the quantitative study of Cryptosporidium parvum with ozone and its evaluation in advanced drinking water treatments. This study reports on the methodology for predicting the ozone inactivation of Cryptosporidium parvum by ozone disinfection in advanced drinking water treatment. The method is based on the fact that a specific inactivation level of microorganisms is achieved at a unique value of ozone exposures, independent of ozone dose and type of water, and quantitatively described by a delayed Chick-Watson model. The required values ${\bar{C}}T$ for 2 log inactivation of Cryptosporidium parvum was $6.0mg/L{\cdot}min$ and $15.5mg/L{\cdot}min$ at $20^{\circ}C$ and $5^{\circ}C$, respectively. From this obtained Cryptosporidium parvum inactivation curves and calculated ${\bar{C}}T$ values of advanced drinking water treatment water in Korea with FIA (Flow injection alaysis), we can predict that water treatment plant can achieve a 1.1~1.8 log inactivation and 0~0.4 log inactivation at $20^{\circ}C$ and $5^{\circ}C$, respectively. This methodology will be useful for drinking water treatment plants which intend to evaluate the disinfection efficiencies of their ozonation process without full scale test and direct experiments with Cryptosporidium parvum.