• 대한환경공학회지
• /
• 제29권4호
• /
• pp.412-418
• /
• 2007

THM 생성은 염소접촉 후 4시간까지 선형적인 증가추세를 보이며, 많은 양의 THM이 생성되는 것으로 나타났으며, 반응 30분만에 168시간 동안 생성된 양의 총 $25\sim43%$의 비율을 차지하였다. 또한, 수중의 브롬이온 농도에 따른 THM 생성특성 조사에서 유기성 전구물질인 humic acid의 농도는 일정하고, 브롬이온의 농도만 $0\sim50{\mu}g/L$까지 변화시켜 염소처리하였을 경우에는 생성되는 총 THM의 농도는 접촉시간 별로 큰 차이가 없는 것으로 나타났다. 수온변화에 따른 THM 생성특성 조사에서 수온이 낮은 $4^{\circ}C$일 때는 PF(parabolic formation) phase로 접어들어서도 THM 생성량이 계속적으로 증가하는 양상을 나타내었으며, $20^{\circ}C$와 $35^{\circ}C$의 경우에는 IF(instantaneous formation) phase까지 급격한 증가추세를 보인 후 PF phase에 도달하여서는 그 증가추세가 둔화되는 것으로 나타났다. pH 변화에 따른 THM 생성특성 조사에서 pH가 5일 경우 IF phase까지 증가추세를 보인 후, PF phase로 접어들어서도 계속적으로 증가하는 것으로 나타났지만 pH가 7과 pH가 9의 경우에는 IF phase까지 급격한 증가추세를 보인 후 PF phase에 도달하여서는 그 증가 경향이 아주 둔화되는 것을 볼 수 있으며, 이런 현상은 pH가 9일 경우에는 더욱 두드러지게 나타났다.

• 분석과학
• /
• 제16권3호
• /
• pp.249-260
• /
• 2003

한강에서 채취한 원수에 염소소독제인 hypochlorite를 $10{\mu}g/m{\ell}$의 농도로 투여한 후 1시간~14일까지 TOC (total organic carbon), 잔류염소량 및 탁도 등을 측정하고 THMs (trihalomethanes), HANs (haloacetonitriles), HKs (haloketones), chloral hydrate 및 HAAs (haloacetic acids) 등의 염소소독 부산물의 생성율을 조사하였다. 그 결과 잔류염소량은 투여후 1시간 경과 시 $6{\mu}g/m{\ell}$ 이상에서 14일째에 $1.23{\mu}g/m{\ell}$으로 감소하였으며 TOC 및 탁도는 큰 차이가 없었다. 7일 후 발생한 총 소독부산 물의 농도는 $101.3ng/m{\ell}$ (789.6 nM)이며 이 중 THMs이 69%로 가장 큰 비중을 차지하였다. 그 외에 HAAs가 19%, chloral hydrate가 10% 정도 검출되었으며, HANs와 HKs 및 chloropicrin 등은 미량 검출되었다. THMs 중에서는 chloroform이 $61.5ng/m{\ell}$로 총 THMs 중 약 89% 정도를 차지하였으며 HANs 중에서는 DCAN이 95%인 $0.72ng/m{\ell}$, HAAs 중에서는 TCAA가 50% 등으로 가장 높은 비율로 검출되었다. 각 부산물의 발생량의 상관관계를 조사한 결과 THMs과 HANs의 경우 THMs의 농도가 $40ng/m{\ell}$인 지점을 경계로 HANs과 경쟁적 발생관계가 있음이 나타났다. HAAs의 경우는 특별한 경향성을 나타내지 않았으나 전체적으로 초기에 산화상태가 큰 화합물에서 산화상태가 작은 화합물로 점차 변화하는 것으로 관찰되었다.

• 한국환경과학회지
• /
• 제14권10호
• /
• pp.965-972
• /
• 2005

This research studied the effect of factors that are able to form disinfection by-products (DBPs) of chlorination, including natural organic matter (NOM) with sewage, bromide ions, pH and contact time. Trihalomethane (THMs) yield of $0.95{\mu}mol/mg$ was higher than other DBPs yield for the chlorinated humic acid samples. THMs yield of sewage sample was $0.14{\mu}mol/mg$ and haloacetonitriles (HANs) yield in the sewage samples were $0.13{\mu}mol/mg$ but only $0.02{\mu}mol/mg$ for the humic acid samples. As the concentration of bromide ions increased, brominated DBPs increased while chlorinated DBPs decreased, because bromide ions produce brominated DBPs. THMs were highest $(55.55{\mu}g/L)$ at a pH of 7.9 and haloacetic acids (HAAs) were highest $(34.98{\mu}g/L)$ at a pH of 5. Also THMs increased with increasing pH while HAAs decreased with increasing pH. After chlorination, the rate of THMs and HAA formation are faster at initial contact time and then reaches a nearly constant value after 24 hours. This study considers ways to reduce DBP formation by chlorination.

• 한국물환경학회지
• /
• 제20권3호
• /
• pp.275-280
• /
• 2004

This study was performed to investigate the disinfection efficiency and the formation characteristics of disinfection by-products(DBPs) by chlorination in the sewage effluent. The effluent was sampled from the sewage treatment plants operated in the activated sludge process and the advanced sewage process. The type of DBPs investigated were Trihalomethanes(THMs), Dichloroacetonitrile(DCAN), Chloral hydrate(CH), Dichloroacetic acid(DCAA), Trichloroacetic acid(TCAA). Major findings are as follows. First, the optimum injection concentration for chlorination in sewage effluent were found to be in the range $0.5{\sim}1.0mg\;cl_2/L$. Also, It was found that the chlorine dosage in the effluent of activated sludge process was higher than in the effluent of advanced sewage process. Second, the maximum formation concentration of THMs were $12.7{\mu}g/L$. The THMs formation reaction was finished in a short time of several seconds and chloroform was mainly formed. Also, it was found that the concentration of ammonium nitrogen is higher, the concentration of THMs is lower. Third, it was found that DCAA and TCAA were mainly formed as DBPs by disinfection.

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

• 분석과학
• /
• 제17권1호
• /
• pp.69-81
• /
• 2004

한강과 낙동강에서 채취한 원수에 염소소독제인 hypochlorite를 $10{\mu}g/mL$의 농도로 투여한 후 1시간 ~ 14일까지 TOC (total organic carbon), 잔류염소량 및 14종의 염소소독부산물 생성율을 조사하였다. 그 결과 TOC 및 탁도는 큰 차이가 없었으며 잔류염소량은 한강에서 투여 후 1시간 경과 시 $6{\mu}g/mL$ 이상에서 14일째에 $1.23{\mu}g/mL$으로 감소한 반면 낙동강의 경우 3일 이후 거의 존재하지 않았다. 7일 후 발생한 총 소독부산물의 농도는 한강의 경우 101.3 ng/mL (789.6 nM)이며 이 중 THMs (trihalomethanes)가 68%로 가장 큰 비중을 차지하였다. 그 외에 HAAs (haloacetic acids, 19%), chloral hydrate(10%)가 검출되었으며, 낙동강의 경우 총 소독부산물의 농도가 98.4 ng/mL (678.6 nM)이며 이 중 HAAs가 57%로 가장 큰 비중을 차지하였다. 그 외에 THMs (34%), HANs (haloacetonitriles, 5%) 및 chloropicrin등 질소화합물의 농도가 증가하였다. 이는 낙동강의 경우 한강에 비해 상대적으로 많이 포함된 암모니아성 질소가 소독제인 염소와 반응하여 클로라민을 생성함으로써 염소에 의한 소독효과와 클로라민에 의한 소독효과를 함께 나타내기 때문인 것으로 사료되며 전체적인 소독부산물들의 생성비율 경향을 살펴보면 소독제의 종류에 따라 소독부산물의 생성패턴에 차이가 있으나 산성도가 큰 HAAs의 초기 생성농도가 높고 점차 THMs의 생성속도가 증가하였다.

• 상하수도학회지
• /
• 제33권3호
• /
• pp.225-234
• /
• 2019

This study is focused on effects of factors that affect the formation of THMs during chlorination in drinking water treatment. During the chlorination, chlorine consumption is increased by increasing the initial chlorine dose, the pH and the total dissolved solid (TDS) concentration. Also THMs formation is increased up to $58.82{\mu}g/L$ and $55.54{\mu}g/L$ by increasing initial chlorine concentration and increasing pH. However, concentration of chloroform is decreased by increasing TDS concentration. This is caused the cation($Na^+$) of the total dissolved solids preferentially reacts with the functional groups of the organic material which influence the trihalomethane formation. But total trihalomethane formation is increased up to $127.46{\mu}g/L$ by $Br^-$ contained in the total dissolved solids. DOC reduction was not influenced by any of the factors.

• 대한환경공학회지
• /
• 제28권11호
• /
• pp.1135-1140
• /
• 2006

국내 정수장에서 염소소독시 발생하는 소독부산물인 트리할로메탄(THMs), 할로아세틱에시드(HAAs)의 발생농도와 각각의 종별 분포현황을 조사하였다. 조사대상은 일반적인 정수처리공정으로 구성된 한강, 금강, 섬진강, 낙동강 수계의 1개 정수장씩 총 4개소였다. THMs의 발생농도는 평균 26.9 ppb, 최대 46.7 ppb, 최소 11.0 ppb였으며, $HAA_5$의 발생농도는 평균 25.4 ppb, 최대 57.1 ppb, 최소 9.7 ppb였다. 계절적으로는 동절기에 농도가 낮았고 하절기에 높았다. THMs의 종별 분포를 조사한 결과 클로로포름의 비율이 평균 77%로 가장 높았고 다음으로는 브로모디클로로메탄(20%)이 높게 검출되었으며, 브로모포름의 농도는 정량한계 미만이었다. $HAA_5$의 경우 디클로로아세틱에시드(DCAA)와 트리클로로아세틱에시드(TCAA)의 합이 $HAA_5$의 97%를 차지하는 것으로 조사되었다. 그러나 한강수계의 경우는 이 비율이 평균 90%로 다소 낮았으며, 특히 겨울철에 비율이 가장 낮았다. 한편, 하절기를 제외하고는 DCAA가 TCAA보다 높은 것으로 조사되었다.

• 한국환경보건학회지
• /
• 제36권5호
• /
• pp.402-410
• /
• 2010

The objectives of this study were to evaluate the air quality surrounding an indoor swimming pool, to estimate the cancer risk based on the airborne exposure to trihalomethanes (THMs), and to examine the ventilation efficiency by Computational Fluid Dynamics (CFD). Chlorine and THMs were measured poolside, and in the staff room and reception area. The indoor swimming pool was modeled using the Airpak program, with ventilation drawings and actual survey data. Temperature, flow and mean age of the air were analyzed. Levels of chlorine poolside, and in the staff room, and reception area were $203\;{\mu}g/m^3$, $5\;{\mu}g/m^3$, and $10\;{\mu}g/m^3$, respectively. Chloroform was the dominant THM in all sampling sites and mean concentrations were $16.30\;{\mu}g/m^3$, $0.51\;{\mu}g/m^3$, and $0.06\;{\mu}g/m^3$ poolside, in the staff room and reception area, respectively. Bromodichloromethane and Dibromochloromethane levels were respectively estimated as $10.3\;{\mu}g/m^3$ and $1.7\;{\mu}g/m^3$ poolside, $1.3\;{\mu}g/m^3$ and $0.1\;{\mu}g/m^3$ in the staff room, and were not detected in the reception area. The cancer risks from inhalation exposure to THMs were estimated between $3.37{\times}10^{-7}$ and $1.84{\times}10^{-5}$. A short circulation phenomenon was observed from the supply air vents to the exhaust air vents located in the ceiling. A high temperature layer was formed within one meter of the ceiling, and a low temperature layer was formed under this layer due to the low velocity and high temperature of the supply air, and the improper locations of the supply air vents and exhaust air vents. The stagnation was evident at the above adult pool and the mean age of the air was 22 minutes. Disinfection by-products in the indoor swimming pool were present in higher concentrations than in the outdoor air. In order to increase the removal of pollutants, adjustment was required of the supply air volume and the supply/exhaust position.

• 한국환경보건학회지
• /
• 제20권4호
• /
• pp.53-59
• /
• 1994

Since trihalomethanes (THMs) and other volatile organic compounds (VOCs) were detected and measured in drinking water supplies in 1974, because of the frequent occurrence of these compounds and the potential health hazard they pose, several methods for detecting VOCs have been developed. The most widely accepted method for the analysis of THMs and other VOCs is a purgeand-trap method. In the analysis of VOCs by purge-and-trap,there are several factors which may give rise to errors. Some of the factors to be considered are purge time, carryover effect, cryofocusing temperature, and trap desorption temperature. In this study,many aspects of purge-and-trap were investigated. Understanding the sources of error makes it possible to adapt the analysis parameters to compensate for such effects.