• 한국산학기술학회논문지
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• 제12권8호
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• pp.3644-3653
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• 2011

본 연구는 수처리 주요공정의 소독공정에 대한 자동운전 구축현황과 목표주입율 결정시 체류시간동안 염소 소모량을 분석하고 활용하기 위한 기술을 연구하고 제시하는데 있다. 본 연구를 위하여 자동운전을 위한 시설물 구조 및 하부설비 설치현황을 조사하였으며, 현 시스템의 문제점을 분석하고 해결을 위한 자동운전 프로그램을 개발하여 적용하였으며 이에 따른 효과도 분석 제시하였다. 특히 시지연공정 및 다변수 공정제어에 적합한 모델예측제어 알고리즘을 적용하여 환경인자와 반응시간 등의 상관관계를 분석하고 최적 제어 입력값을 추론할 수 있도록 함으로써 안정적인 공정제어가 가능함을 모델평가를 통하여 확인하였다.

• 한국환경과학회지
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• 제21권9호
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• pp.1031-1041
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• 2012

This study was carried out to investigate the characteristics of disinfection by-products (DBPs-trihalomethanes (THMs), haloacetic acids (HAAs) and haloacetonitriles (HANs) formation in chlorination of principal raw waters used for drinking water on Jeju Island, Korea. The domestic water supply of other area and humic acid solution (HA) were used as a reference point. The effects of chlorine contact time, solution temperature and pH on DBPs formation potential (DBPFP) were investigated for raw waters. In addition, the effect of $Br^-$ was studied for HA. The DBPFP (THMFP, HAAFP and HANFP) were increased with increasing chlorine contact time. Comparing the individual DBPFPs for raw waters, they decreased in the order of HAAFP > THMFP ${\geq}$ HANFP. As the solution temperature was increased, the THMFP, HAAFP and HANFP increased. With increasing the solution pH, the THMFP was increased, but HAAFP and HANFP were decreased. With the addition of 0.3 mg/L $Br^-$ for HA, the DBPFP was increased and the major chemical species changed: from trichloromethane to dibromochloromethane and tribromomethane for THMs; from dichloroacetic acid and trichloroacetic acid to tribromoacetic acid for HAAs; and from dichloroacetonitrile to dibromoacetonitrile for HANs.

• 환경위생공학
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• 제14권1호
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• pp.11-16
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• 1999

This study was performed to investigate THMs formation by chloramination as a secondary disinfection in drinking water distribution system. As the $Cl_2/NH_3-N$ ratio increased from 1:1 to 4:1, the THMs concentration had actually no change in the breakpoint curve of pH 6, 7. At pH 8, THMs level was not augmented at between 1:1 and 5:1. In the $Cl_2/NH_3-N$ ratio of more than 5:1 and 6:1 respectively, THMs level was raised. Only the chloroform of THMs was insignificantly detected by both preformed chloramine and preammoniation applications, which was probably attributed to the stoichiometrically unstable equilibrium in the preparation of chloramine, whereas $CHCl_3$, $CHCl_2Br$ and $CHClBr_2$ of THMs were found in the application of free chlorine. However it turned out that the THMs levels by chloramine was incomparably inferior to that of free chlorine.

• 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.

• 한국환경보건학회지
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• 제23권2호
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• pp.106-114
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• 1997

When surfactants meet chlorine bleaches not only in the washing drums but also through the whole path from the stream to the river, it is not difficult to expect that they produce the harmful substances like DBPs. Furthermore considering wastewater that is contaminated by surfactants is used to discharge into drinking water sources via sewer system, it also can be imagined that residual surfactants would contribute to the some extent of DBPs' formation during chlorine disinfection in water treatment plants. Although the main behavior observed was the formation of chloroform during the reaction of LAS with free chlorine, the other manifest behaviors like the trends of pH, MBAS, free chlorine, the mole concentration of benzene ring and etc. were also investigated.

• 수도
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• 통권62호
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• pp.69-79
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• 1993

• 한국양식학회지
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• 제16권2호
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• pp.118-123
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• 2003

이산화염소($ClO_2$) 처리에 의한 어병 세균의 살균 효과를 조사하기 위하여 감염어 유래 분리주인 Vibrio anguillarum, Edwardsiella tarda, Streptococcus sp. 및 Streptococcus sp.를 대상으로$ClO_2$유효 농도 0.455, 0.246 및 0.129 ppm에 30초, 1분, 3분, 5분 및 10분간 처리하여 ClO$_2$의 살균효과를 조사하였다. V. anguillarum과 E. tarda는 ClO$_2$ 0.246 ppm에서, 30초 이 상의 처리에 의하여 세균의 증식이 완전히 저해되었다. 그러나 상대적으로 저농도인 0.129 ppm에서는 5분 이상의 염소처리 조건이 필요하였다. Streptococcus sp.는 실험에 사용된 어병 세균 중 $ClO_2$의 살균능이 가장 낮은 것으로 나타났다. 0.455 ppm에서 Streptococcus sp.는 30초 반응 후 그 증식이 완전히 저해되었고, 0.246 ppm과 0.129 ppm의 ClO$_2$에서는 각각 배양 3시간, 8시간 이후부터 그 생잔에 의한 증식이 확인되어졌다. Streptococcus sp.는 본 실험에서 설정한 최저농도인 0.129 ppm 에 30초간의 반응으로 균이 사멸됨으로서 실험에 사용된 세균 중 ClO$_2$에 가장 민감한 것으로 나타났다. 그러므로 Streptococcus sp. 는 0.455 ppm, V. anguillarum과 E. tarda는 0.246 ppm, Streptococcus sp. 는 0.129 ppm의$ClO_2$농도로 30초 전후로 처리하는 조건이 가장 효과적임을 본 연구를 통해 확인할 수 있었다.

• 분석과학
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• 제22권3호
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• pp.272-276
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• 2009

하수처리장 방류수의 염소 소독효율과 소독부산물 발생 특성에 대해 고찰하였다. 총대장균군의 소독효율을 조사한 결과 99% 이상의 소독 효율을 얻기 위해서는 0.5 mg/L에서는 30분, 1.0 mg/L에서는 20분, 1.5 mg/L이상의 농도에서는 10분의 접촉시간이 필요한 것으로 나타났다. 염소주입농도 0.5 mg/L에서 10분간 접촉시킬 때 THMs의 최대 농도는 $32.2{\mu}g/L$이었으며, 이중 chloroform은 최대 $28.4{\mu}g/L$가 생성되어 THMs의 88.1%를 차지하였다. HANs의 최대 농도는 $2.97{\mu}g/L$이었으며, HAAs의 최대 농도는 $16.29{\mu}g/L$로 상당히 낮게 나타났다. 연구대상 하수처리장 최종 방류수의 연평균 잔류염소 농도는 0.4 mg/L이었으며, 염소소독부산물 실험 결과 THMs은 최대 $9.21{\mu}g/L$, 평균 $2.79{\mu}g/L$로 나타났으며 HANs과 HAAs는 검출한계 이하로 나타났다.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 Proceedings of KSEH.Minamata Forum
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• pp.103-114
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• 2005

Chlorine disinfection has been used in drinking water supply to disinfect the water-borne microbial disease which may cause to serious human disease. As Chlorination is still the least costly, relatively easy to use, chlorination is the primary means to disinfect portable water supplies and control bacterial growth in the distribution system. However, chlorine also reacts with natural organic matter (NOM), which presents in nearly all water sources, and then produces disinfection by-product (DBps), which may have adverse health effects. Although the existent DBPs have been reported in drinking water supplies, it is not feasible to predict the levels of the various DBPs due to the complex chemistry reaction involved. The objectives of this study were to investigate seasonal variation of DBPs formation and difference of DBPs concentration in the plant to tap water. The average concentration of THMs was 20.04 ${\mu}g/{\ell}$, HAAs 8-15 ${\mu}g/{\ell}$, HANs 2-4.5 ${\mu}g/{\ell}$ respectively. Distant variation of DBPs formation is that THMs concentration increase by 17% at 2 km point from the plant and by 28% at 7 km and HAAs, HANs also increase each by 16%, 32%, at 2 km from the plant and 35%, 56%, at 7 km. DBPs increase in water supply pipe continually. The seasonal occurrence of DBPs is that in May and August DBPs concentration is very high then in March, in May DBPs concentration is highest. The temperature is main factor of DBPs formation, precursor also. Precursor which was accumulated for winter flowed into the raw water by flooding in spring and summer and produced DBPs. Therefore for the supply of secure drinking water, it is required to protect precursor of flowing into raw water and to add to BCAA and DBAA to drinking water standards.

• 한국식품저장유통학회지
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• 제24권2호
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• pp.312-319
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• 2017

신선 농산물의 비가열 살균에 사용되는 살균소독제는 처리시간과 살균소독제의 농도에 비선형적인 감균효과를 나타낸다. 따라서 실제 사용에 있어서는 적정 농도와 적정 시간에 대한 고려가 매우 중요하다. 본 연구에서는 희석염산(6%, v/v)을 원료로 생성한 미산성 차아염소산수(slightly acidic electrolzyed water, SlAEW)($20{\pm}1^{\circ}C$에서의 유효염소 30 ppm, ORP $562{\pm}23mV$, pH 6.4)로 4종의 채소류(상추, 깻잎, 치콘 및 케일)에 대한 미생물 저감 특성을 분석하여 비가열 살균공정설계에 필요한 살균효과를 평가하였다. SlAEW에 30분간 3회 침지하면서 핵심인자인 유효염소와 미생물군수 및 잔류 미생물군수와의 관계를 분석하였다. 대부분의 총균수 감소는 1차 침지 초기 10분간 이루어졌으며 4종의 채소류에 생존하는 3 log CFU/g의 총균수가 침지를 통해 감소시킬 수 있는 한계값으로 판단되었다. 또한 SlAEW에 10분간 침지함으로써 감소시킬 수 있는 균수는 평균적으로 약 2 log CFU/g이었다. 초기 10분후의 감소된 유효염소는 상추, 깻잎, 치콘 및 케일에 대해 각각 2.2 ppm, 2.0 ppm, 1.7 ppm 및 2.5 ppm이었고 감소된 유효염소량의 약 50-80%가 초기 10분내에 감소되었다.