• 상하수도학회지
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• 제33권6호
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• pp.447-456
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• 2019

This study focused on natural organic matter and trihalomethane removal by ozonation with various ferrous concentration in surface water. Ozonation is more affected by injection concentration than reaction time. dissolved organic carbon removal rates in ozonation increased with the increase in ferrous concentration. The highest removal was obtained at 6 mg/L of ferrous concentration. When 1 mg/L of ferrous was added with 2 mg/L of ozone concentration, it was found to be a rapid decrease in specific ultraviolet absorbance at the beginning of the reaction because ferrous acts as a catalyst for producing hydroxyl radical in ozonation. As ozone concentration increased, trihalomethane formation potential decreased. When 2 mg/L of ozone was injected, trihalomethane formation potential was shown to decrease and then increase again with the increase in ferrous concentration.

• Advances in environmental research
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• 제1권3호
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• pp.181-189
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• 2012

Trihalomethanes, produced as a result of chlorination of drinking water, are considered a potential health hazard. The trihalomethane formation potential (THMFP) of a raw water source may indicate the maximum trihalomethanes (THMs) that are likely to be produced when chlorine reacts with natural organic matter (NOM) present in the water. A study was conducted to evaluate the THMFP in seven different drinking water sources in the vicinity of Kalpakkam, a rural township, on the east coast of India. Water from seven stations were analysed for THMFP. THMFP was compared with surrogate parameters such as dissolved organic carbon (DOC), ultraviolet absorbance ($UV_{254}$) and bromide. The data showed that THMFP was high in water from open wells as compared to closed bore wells, possibly due to more photosynthetic activity. Proximity to sea, and consequently the levels of bromide, was an important factor that influenced THM formation. THM surrogate parameters showed good correlation with THMFP.

• 상하수도학회지
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• 제7권2호
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• pp.34-38
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• 1993

An experimental study was conducted to investigate the effects of chlorine dioxide and ozone on reduction of THM(trihalomethane) formation. Precursor concentration, chlorine concentration, reaction time, pH, and temperature were governing compornents of THM formation. When other conditions are constant, THM formation increased linearly with precursor concentration increased. THM formation increased when pH increased from 5 to 9. In combined treatment with chlorine and chlorine dioxide, chlorine treatment after chlorine dioxide treatment made less THM than any other case does. Ozonation reduced THMFP(THM formation potential) of THM precursor. THMFP decreased exponentially with reaction time increased. Also biodegradability of humic acid was enhanced by ozonation.

• 한국물환경학회지
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• 제20권1호
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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.

• 수도
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• 통권62호
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• pp.69-79
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• 1993

• 한국염색가공학회지
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• 제16권2호
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• pp.34-40
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• 2004

This study was conducted to remove the reactive dyes by the Ozone demand flask method which are one of the main pollutants in dye wastewater, Ozone oxidation of three kinds of the reactive dyes was examined to investigate the reactivity of dyes with ozone, Trihalomethane formation potentials(THMFPs), competition reaction and ozone utilization on various conditions for single- and multi-solute dye solution. Concentration of dyes was decreased continuously with increasing ozone dosage in the single-solute dye solutions. THMFPs per unit dye concentration were gradually increased with increase of ozone dosage. By the result of THMFPs change with reaction time, THMFPs were rapidly decreased within 1 minute in single-solute dye solutions. Dey were increased after 1 minute of reaction time, and then they were consistently decreased again after longer reaction time. Competition quotient values were calculated to investigate the preferential oxidation of individual dyes in multi-solute dye solutions. Competition quotients$(CQ_i)$ and values of the overall utilization efficiency, no$_3$, were increased at 40mg/1 of ozone dosage in multi-solute dye solutions.

• 한국환경과학회지
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• 제8권3호
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• pp.337-347
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• 1999

This study was carried out to evaluate the characteristics of dissolved organics based on their origins, which were divided into two categories. The first group consisted of river, lake and secondary sewage treatment effluent, which were chosen as representative of their origins. The second group were artificial samples which were made of AHA(Aldrich humic acids) and WHA(Wako humic acids). Physicochemical characteristics, biological degradability and THMEP(trihalomethane formation potential) of the samples were analysed based on the AMWD(apparent molecular weight distribution). Large portion of dissolved organic carbon(DOC) in the river and lake samples was comprised of LMW(low molecular weight), which that of AHA and WHA was HMW(high molecular weight). The DOC of the lake was evenly distributed in the all range of molecular weight. The river, lake and secondary treated effluent have lower ultraviolet(UV) absorbance at 254nm, and have a higher amount of humic acids. Higher absorbance of humic acids means that aliphatic bond and benzenoid type components that absorb UV light were contained in these kind of humic acids. It was expected that lake sample was the most biodegradable in the different samples investigated, and in order of secondary sewage treatment effluent, river, WHA and AHA based on the result of determination of specific ultraviolet absorbance(SUVA). Biodegradability showed similar result except for AHA, while dissolved organics in the range of LMW decreased during the biodegradability test, and on the contrary those of HMW increased. Production of the SMPs(soluble micobial products) was observed during humicfication of dissolved organics and the SMPs were higher production of the SMPs. THM formation was high in the samples containing HMW and similar tendency was shown in the THMEP(trihalomethane formation potential), except for WHA.

• 상하수도학회지
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• 제27권1호
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• pp.101-112
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• 2013

Integrated process with coagulation and microfiltration as an advanced water treatment has been expanded its application in recent years due to its superb removal of particles and natural organic matter. In usual, effectiveness of coagulation sometimes determines performance of the whole system. Several new polymeric coagulants introduced to water utilities for better efficiency were studied in this paper. Three polymeric coagulants (i.e., PACl, PACs, and PAHCs) along with alum were evaluated for removal of natural organic matter, especially for reduction of trihalomethane formation potential, for which regulation has become stringent. Turbidity removal was closely related to pH variation showing the reduced turbidity removal by PACs due to the decreases in the pH of supernants at high doses. The four coagulants showed different organic matter removal during coagulation and affected the removal in microfiltration. For instance, DOC concentration was not reduced by microfiltration when PAHCs were used however 10 % of DOC removal was observed by microfiltration with alum coagulation. Coagulation pretreatment also impacted the THM removals, i.e., approximately 30 % of THMs and 13 % of DOC was removed by microfiltration only, but 40 to 67 % of THMs and 30 % of DOC was removed by the integrated process. Strategies on selection of coagulants are needed depending on characteristics of target pollutants in raw waters.

• 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.

• 대한환경공학회지
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• 제29권2호
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• pp.205-213
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• 2007

입상활성탄 및 생물여과 공정에서 활성탄 종류별 DOC(dissolved organic carbon) 흡착능은 석탄계가 가장 우수한 것으로 나타났고, 다음으로 야자계, 목탄계 순으로 조사되었으며, 활성탄 종류별 부착 미생물의 생체량과 활성도는 석탄계에서 가장 높게 나타났으며, 다음으로 목탄계, 야자계, 안트라사이트 순으로 나타났다. 안트라사이트를 이용한 생물여과 공정에서 OM(natural organic matters)의 생분해율은 15분 이상의 EBCT(empty bed contact time)가 주어져야 bed volume에 따라 평균 $10\sim17%$, 최대 $18\sim24%$ 정도의 생분해율을 얻을 수 있었다. NOM의 활성탄 흡착은 주로 친수성 보다 소수성 유기물질과 10,000 Da 이하의 유기물질의 제거가 용이하였으며 HAA5FP(haloacetic acid 5 formation potential) 보다 THMFP(trihalomethane formation potential), BDOC(biodegradable dissolved organic carbon)$_{rapid}$ 보다는 $BDOC_{slow}$의 제거가 용이한 것으로 조사되었다. 생물여과 공정에 의한 유기물질 제거 특성은 주로 친수성과 1,000 Da 이하의 유기물질 제거가 용이하였으며, THMFP 보다는 HAASFP, $BDOC_{slow}$ 보다는 $BDOC_{rapid}$의 제거가 용이한 것으로 조사되었다.