• 한국물환경학회지
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• 제21권6호
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• pp.676-681
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• 2005

This study was researched for disinfection by-products (DBPs) by preozonation, prechlorination and/or postchlorination. DBPs including trihalomethanes (THMs), haloacetic acids (HAAs), halonitriles, and aldehydes were analyzed by the treatment steps of prechlorination, preozonation, sedimentation, filtration, and postchlorination comparatively. THMs were detected as $52.20{\mu}g/L$ after prechlorination and decreased during sedimentation and filtration process. The HAAs and aldehydes increased more during preozonaiton than prechlorination. However, chlorinated DBPs and aldehydes increased more by postchlorination. Chlorinated DBPs formed by preozonation increased 26% more than the chlorination process. If aldehydes were included in the total DBPs, DBPs increased up to 39% by preozonation. Preozonation could increase the removal efficiency of organic carbon during the coagulation and sedimentation processes. Ozonation might produce aldehydes that are not permitted for drinking water regulations. Also, DBPs were produced by preozonation than by chlorination. These results would bring a need for alternative disinfection studies to decrease DBPs.

• 상하수도학회지
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• 제22권6호
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• pp.633-640
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• 2008

In this research, the $3.6m^3/day$ scale pilot plant consisting preozonation, coagulation, flocculation, and ceramic membrane processes was operated for long term period to evaluate the validity of ceramic membrane filtration process for treating lake water containing high concentration manganese. The higher concentration of dissolved manganese($Mn^{2+}$) was effectively oxidized to the bigger insoluble colloidal manganese ($MnO^2$) by 1~2 mg/L ozone. The colloidal manganese reacted with coagulant (poly aluminium chloride, PAC) and then formed the big floc. Ceramic membrane rejected effectively manganese floc during membrane filtration. Dissolved organic carbon(DOC) removal was dependent upon $Mn^{2+}$ concentration. While average $Mn^{2+}$ concentration was 0.43 and 0.85 mg/L in raw water, DOC removal rate in preozonation was 26.5 and 13.5%, respectively. The decrease rate of membrane permeability was faster without preozonation than with preozonation while membrane fouling decreased with NOM oxidation by ozone. In conclusion, raw water containing high concentration of manganese can be effectively treated in preozonation-coagulation-ceramic membrane filtration system.

• Environmental Engineering Research
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• 제7권4호
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• pp.191-198
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• 2002

• 환경위생공학
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• 제12권1호
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• pp.69-75
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• 1997

Biological drinking water treatment is widely used in Europe for the removal of ammonia nitrogen and organics. During the last 16 years, the deterioration of the quality of surface waters used to produce drinking water has resulted in the widespread use of ozone-biological treatment in Korea. This study were conducted to determine the effect of media weight and preozonation on the biodegradability enhancement in biological fluidized bed(BFB) using Han river water. When the carbon weight was increased, $NH_{3}-N$ and DOC removal increased, but turbidity and SS removal decreased. To remove turbidity and SS, the bed depth in 40% expansion rate/total bed depth was very important. Preozonation of raw water was not effective in $NH_{3}-N$, but increased in biodegradable organic fraction about 10-30% with 0.425-0.85 mg $O_{3}/mg$ DOC.

• 환경위생공학
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• 제13권1호
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• pp.166-173
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• 1998

This study was to investigate the effects of preozonation on the waterborne organic removal by the biologically active GAC fluidized bed on a laboratory scale. The raw water to be treated comes from midstream of Han river. As the ozone dose was increased in the range of $1~3{;\}mgO_{3}/mgDOC$, it produced BDOC from 1.82 to 2.65 times. And BDOC formation can be expressed as [BDOC] = 0.74 + 0.21[DOC] ($R^{2}{\;}={\;}0.8399$). The effects of combination of ozonation followed by BACFB (Biological Activated Carbon Fluidized Bed) process were analyzed. At the ozone doze of $1~3{\;}mgO_{3}/mgDOC$, the large fraction of BDOC was removed by BACFB, but parameter revealed only around 10% reduction.

• 한국환경보건학회지
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• 제22권4호
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• pp.69-76
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• 1996

Biological process have the potential to remove pollutants such as biodegradable organic fraction, $NH_3-N$, ABS, etc. that may be partially removed by conventional water treatment. This study was performed to evaluate four different processes of biological pretreatment as Biological Fluidized Bed(BFB), Biological Filter(BF), Rotating Biological Contactor(RBC) and Honey Comb(HC). In a given condition it proved out that BFB and BF are prospective biological pretreatment processes because they were the most effective on the removal of organic matter and ammonia. Preozonation of raw water for biological processes increased in biodegradable organic fraction about 10-40% with 0.425-0.85 mg $O_3/mg$ DOC.

• 한국환경과학회지
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• 제10권6호
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• pp.393-399
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• 2001

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using ozonation. for raw water, Nakdong River was used. By conducting batch ozonation test, the following results were obtained. when ozone dosage of 5mg/$\ell$was used, preozonation of raw water reduced turbidity, KMnO$_4$consumption, DOC(dissolved organic carbon), UV254 absorbance, THMFP(trihalomethane formation potential) as much as 3.9NTU, 5.5mg/$\ell$, 1.15mg/$\ell$, 0.112 and 0.065mg/$\ell$, respectively. In case of postozonation of sand filtered water, water quality was also improved with decrease in turbidity, KMnO$_4$consumption, DOC, UV254 absorbance and THMFP at the amount of 0.08NTU, 2.6mg/$\ell$, 0.88mg/$\ell$, 0.042 and 0.018mg/$\ell$, respectively. On the other hand, contents of dissolved oxygen increased at the level of 1.3mg/$\ell$ after preozonation process and 1.0mg/$\ell$ after postozonation process. The effect of ozone dosage was higher than that of its contact time for the removal of the pollutants.

• 한국환경과학회지
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• 제13권1호
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• pp.55-59
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• 2004

The effect of ozone on the formation and the removal of disinfection byproducts(DBPs) of chlorination process was studied to elucidate the performance of water treatment process. The samples of raw water, prechlorination process, and preozonation process were analyzed quantitatively according to the Standard Methods for the Examination of drinking water. As a result, most of total trihalomethanes(THMs) which were formed in prechlorine treatment process was not removed in the preozonation process. Most of haloacetic acids(HAAs), haloacetonitriles(HANs), and chloral hydrate(CH) was removed in sedimentation and biological activated carbon(BAC) filtration processes. However, DBPs were increased more or less by postchlorine step. In particular, the formation of THMs and HAAs depends on ozone more than chlorine, but, the formation of HANs and CH depends on chlorine more than ozone. The seasonal variation of DBPs concentration for the year needs to be investigated to study the temperature effect because DBPs strongly depend on temperature among various efficient factors.

• 한국환경농학회지
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• 제21권3호
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• pp.189-196
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• 2002

낙동강 상수원수를 대상으로 연속적 오존처리에서 오존주입농도에 따른 유기물 분해 특성을 조사하기 위하여 오존처리에 의한 DOE성분변화, UV254/DOC의 변화와 소비오존에 따른 DOC 제거효율을 조사한 결과는 다음과 같다. 유입원수의 수질변화에 따라 다소 차이는 있었으나 전반적으로 오존주입농도가 증가할수록 DOC 처리효율도 증가되었다. 오존처리에 따른 DOC 성분변화는 전오존을 3 mg/L 농도로 처리시 TDOC, ADOC, A &BDOC 및 NRDOC는 각각 0.6, 0.2, 0.1 및 1.0 mg/L 정도 오존처리에 의하여 감소되었으나 BDOC는 0.8 mg/L 증가하였다. UV254/DOC의 분율은 오존주입농도를 1, 3 및 5 mg/L처리하였을 때 전오존의 경우는 각각 0.048, 0.044 및 0.037 이였고, 후오존의 경우는 각각 0.018, 0.015 및 0.012로 나타나 오존주입농도가 증가할수록 감소하는 경향을 보였다. 초기 DOC mg당 소비되는 오존량에 대한 DOC 제거율은 전오존과 후오존처리의 초기 DOC에 대한 소비오존량이 각각 약 1.5와 2.3일 때 각각 25%와 32%로 서 최대의 DOC 처리효율을 나타내었다. 낙동강 상수원수에 전오존을 처리할 경우 오존주입량은 초기 DOC mg당 소비된 오존이 1.5 mg 이내의 농도가 되도록 주입하구 후오존은 유입수인 모래여과수의 초기 DOC mg당 소비된 오존이 2.3 mg 이내의 농도가 되도록 조절하여 주입하면 적당할 것으로 생각되었다.

• 상하수도학회지
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• 제11권2호
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• pp.65-75
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• 1997

Removal characteristics of volatile organic carbons(VOCs) by ozone oxidation and other processes in the raw water of the 1st Nakdong water treatment plant were investigated. Dichrolomethane, toluene and other 7 compounds were detected in the raw water. With regard to detected 4 compounds in finally treated water, it was found that VOCs could not be removed effectively by traditional water treatment process. Benzene, 1,2-dichlorobenzne were not detected in the raw water but they were detected in the process of treatment. The compound of highest detection frequency was dichloromethane. When the raw water was controlled at pH 7, temperature $20^{\circ}C$, 5 minutes as contact time, 10 minutes as reaction time, the removal rate of THMFP, $KMnO_4$ demand, TOC, $UV_{254nm}$ and $NH_3-N$ were 46.4%, 22%, 19.6%, 31% and 8%, respectively. From estimating the finally treated water qualities in 7 kinds of treatment processes, P-6 process(raw water-chlorination-coagulation-ozonation) was most effective for organics removal and THMs control. Removal efficiencies for $KMnO_4$ demand and TOC by the process which combined preozonation with coagulation was twice better than only preozonation. $NH_3-N$ removal rate was shown as 10% by P-3 process(raw water-coagulation-ozonation), but 83% of $NH_3-N$ was removed by P-4 process(raw water-coagulation-chlorination). It was found that the chlorination is more effective than the ozonation for the NH3-N removal as commonly known.