• Journal of Korean Society of Environmental Engineers
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• v.37 no.9
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• pp.505-510
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• 2015

This study investigated formation potential of 16 disinfection byproducts (DBPs) (e.g., g trihalomethanes, haloacetic acids, haloacetonitriles, chloral hydrate, etc.) upon chlorination of raw water at various pH, water temperatures, and chlorine doses. We also compared the DBP formation potential (DBPFP) of raw and filtered waters. Most of DBPs were formed higher at neutral pH, but dichloroacetic acid, chloroform, and bromodichloromethane were formed higher over pH 7. As water temperature increased, concentrations of chloral hydrate, haloacetic acids, and haloacetonitriles linearly increased while that of trihalomethanes exponentially increased. Formation of chloral hydrate, trihalomethanes, and trihaloacetonitriles significantly increased up to 2.0 mg/L $Cl_2$ of chlorine addition, then gradually increased at 2.0~5.6 mg/L $Cl_2$. Filtered water formed less DBPs than raw water in most DBPs except for trihalomethanes.

• Environmental Analysis Health and Toxicology
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• v.20 no.1
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• pp.29-37
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• 2005

Recently, significant contamination problems by residual chemicals have occasionally been occurred from major rivers and drinking water in Korea. Therefore, the management for use of them and risk assessment should be more strictly performed. In this study, we have analyzed trihalomethanes in treated water samples taken from water plants located in the region of four major rivers (i.e. Han river, Geum river, Youngsan river and Nakdong river) in Korea for eight years (1997～2004). From the data, we could assess the excess cancer risk by calculating the chronic daily intakes (CDI) multiplied by individual oral slope factors, Q₁＊, for the cancer suspected matters such as trihalomethanes, moreover the hazard index which is calculated by dividing the CDI by the acceptable daily reference dose (R/sub f/D) was determined for the risk assessment. As a result, in the case of 95 percentile excess cancer risk, it was shown that the excess cancer risk for dichlorobromomethane in the Nakdong river region is highest among the tested samples as 8.73 x 10/sup -6/. The 95 percentile total hazard index (the sum of individual hazard indices considering R/sub f/D), in addition, was below 1.0 for all samples, and therefore it was assessed that water samples taken from treatment plants of four major rivers are not harmful.

• Journal of Environmental Science International
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• v.24 no.1
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• pp.65-71
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• 2015

This study accessed the adsorption characteristics of the 9 trihalomethanes (THMs) on coal-based granular activated carbon (GAC). The breakthrough appeared first for $CHCl_3$ and sequentially for $CHBr_2Cl$, $CHBr_3$, $CHCl_2I$, CHBrClI, $CHBr_2I$, $CHClI_2$, $CHBrI_2$, and $CHI_3$. The maximum adsorption capacity (X/M) for the 9 THMs with apparent breakthrough points ranged from $1,175{\mu}g/g$ (for $CHCl_3$) to $11,087{\mu}g/g$ (for $CHI_3$). Carbon usage rate (CUR) for $CHCl_3$ was 0.149 g/day, 5.5 times higher than for $CHCl_3$ (0.027 g/day).

• 수도
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• s.29
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• pp.48-51
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• 1983

다음의 기사는 AWWA에 의하여 출판되었고, AWWA 연수계획조정자인 MR. Dee Cooperider에 의해 준비된 THM 세미나 자료중에서 "상수중의 THM규제를 위한 처리 기술" 중에서 발화 것이다.

• Journal of Environmental Science International
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• v.13 no.3
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• pp.297-300
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• 2004

We have been proposed model equation which is able to predict the trihalomethane producing concentration formation, that is one of byproduct, in the water treatment processes. In proposed model, the effects of trihalomethane factors like chlorine contact time, pH, temperature, TOC and UV-254 are considered. The concentration of the trihalomethane produced is proportion to the contact with chlorine, pH of water, temperature of water TOC and UV-254, respectively. This proposed model could be predicted the formed concentration of trihalomethanes by trihalomethane factors.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.472-479
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• 1994

This study was conducted to determine the effective removal method of THMs and humic material in drinking water when the doses of oxidants, coagulants, and activated carbon, and the points of oxidants treatment were changed in the drinking water treatment process. The inhibition of THMs formation and the removal of humic matter were more effectively achieved by $ClO_2$ than by other oxidants, $Cl_2,\;NH_2Cl,\;KMnO_4\;and\;O_3$. By changing the point of oxidant treatment, the formation of THMs was reduced by about 36.7 to 8.2% on treatment after coagulation, but the content of humic matter was not affected. The coagulation efficiency of alum and ferric sulfate to coagulate organic materials in water was affected by the molecular weight of humic matter in drinking water. The treatment of activated carbon after filtration was found to be more effective than that before oxidation in inhibiting THMs formation and removing THMs.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.83-87
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• 2012

Activated carbon fiber (ACF) was used to remove four kinds of trihalomethanes(THMs) from tap water which were remained as by-products during the chlorination of water. Adsorption capacity was investigated as a function of THMs concentration and solution temperature, and adsorption mechanism was studied in relating to the surface characteristics of ACF. All the four kinds of THMs were rapidly adsorbed on the surface of ACF by physical adsorption due to the enormous surface micropores and chemical adsorption due to the hydrogen bonds, showing a Langmuir type adsorption isotherm. Langmuir type is especially profitable for the adsorption of low level adsorptives. ACF was very effective for the removal of THMs from tap water because the THMs concentration is below $30{\mu}g/L$ in tap water. The adsorption amount of THMs on ACF increased in order of the number of brom atom; chloroform, bromodichloromethane, dibromochloromethane, and bromoform. The adsorption capacity increased as increasing the number of brom atom due to the decrease of polarity in solution. The adsorption capacity of THMs on ACF can be enhanced by proper surface treatment of ACF.

• Analytical Science and Technology
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• v.28 no.1
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• pp.58-64
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• 2015

This study aimed to investigate the concentration distributions and formation characteristics of trihalomethanes (THMs) in drinking water supplies to rural communities. Water samples were collected twice from 40 rural households located on the outskirts of Chuncheon city of Gangwon Province in the summers of 2010 and 2011, and urban drinking water samples were collected from 20 faucets during the same period in 2011 for comparison purpose. Water temperature, pH, and residual chlorine (total and free) concentrations were measured in the field, and samples were analyzed for dissolved organic carbon (DOC) and THM concentrations in the laboratory. The average DOC concentrations in rural water samples were not greatly different between groundwater (n = 20) and surface water (n = 20) which were used as sources for drinking water (1.81 vs. 1.91 mg/L). However, the average concentrations of total THMs (TTHMs) in groundwater ($9.77{\mu}g/L$) were much higher than those in surface water ($2.85{\mu}g/L$) and similar to those in urban drinking water samples ($10.8{\mu}g/L$). Unlike urban water supply, rural water (particularly groundwater) contained more brominated THM species such as dibromochloromethane (DBCM), suggesting its relatively high content of bromide ion (Br-). This study showed that rural water supplies have different THM formation characteristics from urban water supplies, probably due to their differences in source water quality properties.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.1
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• pp.121-130
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• 1996

Adsorption isotherms of three trihalomethanes(THMs: $CHCl_3$, $CHBrCl_2$ and $CHBr_2Cl$) and the other organics(p-chlorophenol and sucrose)on activated carbon fibers(ACFs) were measured. Adsorption capacities of the ACFs for these THMs were found to be comparable with or slightly larger than those of granular activated car bons(GACs) which have been widely used for trihalomethanes control in drinking water. Also, the breakthrough curve prediction was successfully carried out using a mathematical model on basis of the assumption that the adsorption equilibrium is instantaneously established when a THM solution contacts the ACF. In practice, THM removal from drinking water was investigated at water works using benchscale ACF adsorptJOn columns. The volume of water treated at a space velocity(SV) of about $100h^{-1}$ was approximately 40 l/g-ACF. The practical adsorption capacities of PCP and sucrose in column adsorption were in good agreement with those of theoretically calculated results using the batch adsorption measurments. And the saturation time model of these substrates in the columns was also agreed succesfully with practical measurments.

• Journal of Korea Water Resources Association
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• v.30 no.3
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• pp.235-245
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• 1997

A pilot scale study for removing odor and trihalomethane formation potential (THMFP) was investigated in the standard water treatment plant equipped with ozone oxidation and granular activated carbon (GAC) adsorption processes. The removal efficiency of dissolved organic carbon (DOC) in the pilot scale standard water treatment process (PSWTP) was about 25%, however, no more removal in the ozone oxidation process. On a GAC after 30 days operation, DOC removal efficiency was about 75%. Odor removal efficiency was about 30% in PSWTP, 60% in ozone oxidation, and almost complete in well as DOC. Mid-1 and 2 that showed breakthrough in odor inducing material as well as DOC. Mid-1 and 2 chlorination was able to reduce trihalomethanes (THM) by 25% compared to prechloringation, while postchlorination alone could reduce them by 30%.