• Journal of Environmental Science International
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• v.23 no.9
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• pp.1635-1642
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• 2014

Haloacetic acids (HAAs) concentrations have been observed to decreased at drinking water distribution system extremities. This decrease is associated with microbiological degradation by pipe wall biofilm. The objective of this study was to evaluate HAAs degradation in a drinking water system in the presence of a biofilm and to identify the factors that influence this degradation. Degradation of monochloroacetic acid (MCAA), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) was observed in a simulated distribution system. The results obtained showed that different parameters came into play simultaneously in the degradation of HAAs, including retention time, water temperature, biomass, and composition of organic matter. Seasonal variations had a major effect on HAAs degradation and biomass quantity (ATP concentration) was lower by 25% in the winter compared with the summer.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.145-150
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• 2004

This study investigated the effect of chlorine dose and chlorine reaction time for the formation of haloacetic acids (HAAs). According to the results, HAA formation was highly affected by chlorine dose and chlorine reaction time. HAA formation reached a plateau value at 30 mg/L of chlorine dose and 24 hr of chlorine reaction time. For the speciation of formed HAAs in the test water, the concentration of brominated-HAAs was significantly lower than that of chlorinated-HAAs because of low level of bromide ion concentration in the test water. It also investigated the removal efficiency of HAA precursors by several unit processes, such as ozone alone, UV alone, and combined ozone/UV system. Of them, ozone/UV system was proved as the best process to control the HAAs formation. The increase of the brominated-HAAs was observed during ozonation with and without UV irradiation showing the slight increase of total HAA concentrations.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.23-29
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• 1997

The main reason of applying chlorination is to sterilize microbes existing in the drinking water treatment. But chlorination could lead to the formation of disinfection by-products (DBPs) by the reaction of free chlorine with humic substance in the water. Especially the DBPs including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and haloketones (HKs) exist in the tap water. The US environmental protection agency (US EPA) defines that trihalomethanes, dichloroacetic acid, trichloroacetic acid, and dichloroacetonitrile among DBPs are probable/possible human carcinogens. US EPA suggests maximum contaminant levels (MCLs) for THMs (80$\mu$g/L) and HAAs (60$\mu$g/L) in drinking water. In Korea, THMs in drinking water has been surveyed but DBPs in general has not been studied in drinking water practically. Therefore only THMs have been regulating as criteria compounds since 1990 but neither HAAs nor HANs. Researches on HAAs are yet to be found. HAA formation potentials(HAAFPs) have not been practiced. HAAs depends on the characteristics of water sources by chlorination. In this study, HAAFPs from three distinct sources were investigated by laboratory chlorination experiments. This study was performed to measure the level of HAAs in drinking water in Seoul area. At April 1996, after collecting the raw waters from the three sites with the different properties, the water samples were chlorinated at various conditions(pH 5.5, pH 7.0 and without pH adjustment) in the state of raw water to have 0. 5mg/L of residual chlorine concentration. And the raw water, treated water, and tap water of water treatment were collected to measure the HAAs concentration. The quantitative analysis of HAAs was conducted by US EPA methods.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.638-648
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• 2004

In many drinking water treatment plants, chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of haloacetic acid (HAAs). In this study, headspace solid-phase microextraction (HS-SPME) was studied as a possible alternative to liquid-liquid extraction for the analysis of HAAs in drinking water. The method involves direct derivatization of the acids to their methyl esters without methyl tert-butyl ether (MTBE) extraction, followed by HS-SPME with a $2cm-50/30{\mu}m$ divinylbenzene/carboxen/polydimethylsiloxane fiber. The effects of experimental parameters such as selection of SPME fiber, the volume of sulphuric acid and methanol, derivatization temperature and time, the addition of salts, extraction temperature and time, and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The $2cm-50/30{\mu}m$-divinylbenzene/carboxen/polydimethylsiloxane fiber, sulphuric acid of 1ml, methanol of 3ml, derivatization temperature of $50^{\circ}C$ derivatization time of 2hrs, sodium chloride salt of 10g, extraction time of 30 minutes, extraction temperature of $20^{\circ}C$ and desorption time of 1 minute at $260^{\circ}C$ were selected as the optimal experimental conditions for the analysis of HAAs. The linearities ($r^2$), relative standard deviations (%RSD) and limits of detection (LOD) for HAAs were 0.9978~0.9991, 1.1~9.8% and $0.05{\sim}0.2{\mu}g/l$, respectively.

• Journal of Korean Society on Water Environment
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• v.20 no.1
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• pp.55-62
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• 2004

This study was carried out to investigate the formation of DBPs(Disinfection By-products) such as trihalomethane(THMs) and haloacetic acid(HAAs) by chlorination in raw water and finished water of Water Treatment Plant(WTP). The formation of THMs was increased with the increase of pH and reaction time. HAAs was found as a high formation at a pH 7 and low formation at pH 9. THMFP(Trihalomethane Formation Potential) was the highest formation potential in raw water of Pu-1 and the lowest in raw water of Pa-1. In case of HAAFP(Haloacetic acid formation potential), So-1 showed the highest value, while Pa-1 showed the lowest value. It was investigated the relationship between HAAs and organic matters which were described as DOC(dissolved organic carbon) and $UV_{254}$. In both DOC and $UV_{254}$ versus HAAFP, Pu-1 showed the good correlation coefficients($r^2$) with 0.95 and 0.84, respectively. For three WTP investigated, DBPs(THMs + HAAs) was shown over the range of $42.00{\sim}49.36{\mu}g/L$. This result might be due to the different characteristic of organic matters in raw water and the difference of chlorine dosage for a water treatment.

• Journal of Environmental Science International
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• v.21 no.9
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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.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.2
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• pp.63-70
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• 2016

The distributed systems managed by K-water were surveyed to study the characteristic of disinfection-by-product (Trihalomethans & Haloacetic acids) formation and the correlations between the concentrations of disinfection-by-product and physico-chemical parameters. Five distribted system were selected according to their water ages and the degree of deterioration of their pipelines. Total seven items including Trihalomethans (THMs), Haloacetic acids (HAAs), BDOC, DOC, pH, chlorine residual, and temperature were analysed in monthly basis. The concentration of organic matter were increased according to water age and pipeline deterioration in this study. The coefficient of determination between the decline of residual chlorine and the increase of water age was revealed as high. Also, the coefficient of determination between the decline rate of residual chlorine and the increase of the Trihalomethans concentration were studied as high. Furthermore the longer water age is the bigger the effect on Trihalomethans formation and temperature. However, the coefficient of determination between the concentraion of Haloacetic acid and water age, residual chlorine, and temperature were revealed as low in this study.

• Analytical Science and Technology
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• v.16 no.3
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• pp.249-260
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• 2003

The disinfection of drinking water to control microbial contaminants results in the formation of secondary chemical contaminants, DBPs (disinfection by-products). It was studied the formation pattern of DBPs in drinking raw water after hypochlorite, chlorine disinfectant, was added in this study. It was determined TOC (total organic carbon), residual chlorine, turbidity and DBPs in raw water from Han-river during 1~14 days. Total DBPs was $101.3ng/m{\ell}$ (789.6 nM) after 7days and THMs (trihalomethanes) are the dominant portion of 69%. HAAs (haloacetic acids) and chloral hydrate were determined 19% and 10% respectively, and HANs (haloacetonitriles), HKs (haloketones) and chloropicrin were analyzed in trace level. Chloroform occupied about 89% in total THMs in concentration of $61.5ng/m{\ell}$, 95% of HANs was DCAN (dichloroacetonitrile) in $0.72ng/m{\ell}$, 50% of HAAs was TCAA (trichloroacetic acid). On the study of relationship in formation among the DBPs, HANs forms with THMs competitively to the point of the concentration of $40ng/m{\ell}$ of THMs. For HAAs, it did not show the prominent tendency. But it was observed that the compounds of large oxidation state are formed at first, and becomes to the compounds of low oxidation states.

• Journal of Environmental Science International
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• v.15 no.8
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• pp.785-797
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• 2006

The formation characteristics of trihalomethanes (THMs) and haloacetic acids (HAAs) were investigated in chlorination of raw water of different organic mallet characteristics. The samples used in this study were hydrophobic (N-HPO) and hydrophilic fraction (N-HPI) (which were concentrated and separated from Nakdong river water), and humic acid (HA) (which is known as a strong hydrophobic acid) as a reference organic matter, the specific UV absorbance (SUVA) of which was 2.19, 1.15 and 7.92, respectively. With increasing chlorine contact time, THMFP and HAAFP (the formation potential of THMs and HAAs) increased, but their increase was different depending on the organic mallet characteristics (i.e., for N-HPI, THMFP was higher than HAAFP, but the inverse result was obtained for N-HPO and HA and the ratio between them was greater for HA), and the mainly formed chemical species were CHCI$_3$ in case of THMs and dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) in case of HAAs for N-HPO and HA (and the ratios of CHCI$_3$ to total THMs and DCAA and TCAA to total HAAs for HA were higher than those for N-HPO), but for N-HPI, the ratio of brominated THMs was a little higher than that of CHCI$_3$ and the ratio of DCAA and TCAA to total HAAs was lower than that of N-HPO, although they are main chemical species in case of HAAs. Comparing THMFP and HAAFP with the increase in bromide concentration added with those in not adding it, the former increased greatly and its increase was higher for the organic mallet with stronger hydrophobicity, but the latter was lower for N-HPO and N-HPI and was similar for HA. The main chemical species with increasing bromide concentration were CHBt$_3$ in case of THMs regardless of organic matter characteristics, and dibromoacetic acid (DBAA) for N-HPO and N-HPI, DBAA and tribromoacetic acid (TBAA) for HA in case of HAAs. With increasing reaction temperature and pH, THMFP and HAAFP increased for the former, but for the latter, THMFP increased and HAAFP decreased, although the rate of increase or decrease was different with organic mallet characteristics.

• Analytical Science and Technology
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• v.17 no.1
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• pp.69-81
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• 2004

The formation pattern of DBPs (disinfection by-products) in raw water treated with hypochlorite, chlorine disinfectant was studied. TOC (total organic carbon), residual chlorine, turbidity and 14 DBPs in raw water from Han-river and Nakdong river during 1 ~ 14 days were determined. Total DBPs in Han river was 101.3 ng/mL (789.6 nM) after 7days and THMs (trihalomethanes) are the dominant portion of 68%. HAAs (haloacetic acids) and chloral hydrate were determined 19% and 10% respectively. In Nakdong river total DBPs was 98.4 ng/mL (678.6 nM) and dominant class was HAAs. (55.8 ng/mL, 57%) THMs(34%) and N-compounds like HANs (haloacetonitriles, 5%) and chloropicrin were increased. It may be explained that high concentration of NH4-N in Nakdong river react with chlorine produced chloramine and this formed different pattern of DBPs. As a result, total DBPs formation pattern depends on raw water and disinfectant and in generally the initial concentration of acidic HAAs was high and THMs was increased gradually.