색도물질과 옥살산의 오존분해를 위한 고효율 Jet Loop 반응기의 적용

변석종,조순행,윤제용,김수명,Byun, Seok-jong,Geissen, Sven-Uwe,Vogelpohl, Aflons,Cho, Soon-haing,Yoon, Je-yong,Kim, Soo-Myung 한국물환경학회 2004 한국물환경학회지 Vol.32 No.2

As an ozone contactor, we newly adopted HJLR (High-performance Jet Loop Reactor) for the decolorization of Reactive black 5 and the mineralization of oxalic acid, which has been applied exclusively in biological wastewater treatments and well-known for high oxygen transfer characteristics. The ozonation efficiency for organic removals and ozone utilization depending on the mass transfer rate were compared to those of Stirred bubble column reactor, which was controlled by varing energy input in the HJLR and Stirred bubble column reactor. The results were as follows; first, the decolorization rate of Reactive black 5 in the HJLR reactor was nearly proportional to the increasing $k_La$. When the $k_La$ was increased by 25 % from $13.0hr^{-1}$ to $16.4hr^{-1}$, 30 % of the k' (apparent reaction rate constant) was increased from 0.1966 to $0.2665min^{-1}$ (Stirred bubble column; from 0.1790 to $0.2564min^{-1}$). Ozone transfer was found to be a rate-determining step in decolorizing Reactive black 5, which was supported by that no residual ozone was detected in all of the experiments. Second, the mineralization of oxalic acid was not always proportional to the increasing $k_La$ in the RJLR reactor. The rate-determining step for this reaction was OH(OH radical) production with ozone transfer, because residual ozone was always detected during the ozonation of oxalic acid in contrast with Reactive black 5. This result indicates that the increase of $k_La$ in the HJLR reactor is beneficial only when there are in ozone transfer limited regions. In addition, regardless of $k_La$, the mineralization of oxalic acid was nearly accomplished within 60 minutes. It was interpreted as that the longer staying of residual ozone by whirling liquid in the HJLR reactor contributed to an high ozone utilization(83-94%), producing more OR radicals.

추적자 실험에 의한 정수장 침전지내 구조물의 수리학적 영향평가에 관한 연구

윤제용(Je Yong Yoon),변석종(Seok Jong Byun),이상덕(Sang Deok Lee),김정현(Jeong Hyun Kim),권순범(Soon Buhm Kwon) 한국수처리학회 1999 한국수처리학회지 Vol.7 No.1

Sedimentation basin is one of the most common and important units in the conventional water treatment plant. It plays an important role in removing the floc formed in mixing and coagulation basin, and then has a great impact on the backwash cycle of filtration process. Plug flow pattern in sedimentation basin which is the most desirable, never exists on its own in a real basin. It is always accompanied by a certain degree of mixing and dead space. Structures such as the inlet and outlet of basin, the location of baffle wall, the installation of sludge collector may be the obstacles to the horizontal flow when it is poorly designed. Therefore, to know how these structures in the settling basin have an influence on the characteristics of hydraulic flow is beneficial to improve the settling efficiency of the floc. The hydraulic characteristics of the sedimentation basin in the three real WTPs(B, K, I) which have the different structural characteristics inside the settling basin were qualitatively investigated by the tracer test. Quantitative evaluation was not attempted due to the poor recovery of tracer chemical. First plant(B plant) has a plate settler. Second plant(K plant) has baffle wall cut about 60 cm in the bottom for the purpose of installation of the sludge collector. Third plant (I plant) does not have any structure in the basin. It was found that structures such as plate settler(B plant) and baffle wall cut in the bottom had an profound undesirable impact on the horizontal flow in the settling basin. Tracer distributions clearly indicated that any space occupied by plate settler in B plant was the complete dead zone, on the contrary to its intended role. Also, the baffle wall cut in the bottom in K plant was not as good as the plate settler in B plant in having the horizontal flow in the sedimentation basin. Even for I plant which has no structure in the basin, the limited horizontal flow was observed, though showing the best hydraulic performance among the three plants.

국내 상수원수 및 정수에서 암모니아성질소 검출특성

윤제용(Je Yong Yoon),변석종(Seok Jong Byun),김해심(Hae Shim Kim),조순행(Soon Haing Cho) 한국물환경학회 2001 한국물환경학회지 Vol.17 No.4

Ammonia is sometimes considered as a indicator parameter for organic pollution in fresh water. The presence of ammonia in fresh water could be harmful to aqueous ecosystem, depending upon its concentration and pH. In addition, the reaction of ammonia with chlorine may produce organic chloramines causing taste and odor problems in treated water. We investigated the characteristics of ammonia concentration (NH₃-N) in raw water and treated water in Korea. The water quality data during 5 years (1994-1998) were collected from the Ministry of Environment. The number of ammonia data in raw water and treated water was 7,091 from 592 raw water monitoring sites, and 34,134 from 600 water treatment plants, respectively. Ammonia was detected in 37.6% out of 7,091 raw water monitoring data. 88.4 out of the ammonia detected samples were below 0.1 ㎎/L. The frequency of ammonia detection in both raw water and treated water has been gradually decreased for last five years. The number of data exceeding 0.5 ㎎/L was 283(3.6%) and many of these samples occurred in winter. It is attributed to the lack of nitrification of ammonia due to low temperature.

국내 정수장에서 염소주입 특성 및 잔류염소 분포에 관한 연구

윤제용,변석종,이상덕 ( Je Yong Yoon,Seok Jong Byun,Sang Duck Lee ) 한국물환경학회 1997 한국물환경학회지 Vol.13 No.3

Chlorine is currently being used to control microorganism, odor, color and inorganics such as Fe, Mn in nearly all domestic water treatment plants. However, an overdose of chlorine can cause the formation of unexpectedly high disinfection byproducts(DBPs) such as trihalomethanes, besides being econonomically not sound. On the other hand, under dosage of chlorine may increase public health risk resulting from waterborne disease. Therefore, it is necessary to investigate the characteristics of chlorine dosage in water treatment plants to provide the proper guideline of chlorine practice. In this study, five water treatment plants were selected for investigating for characteristics of chlorine dosage and distribution of residual chlorine. Three major characteristics of chlorine dosage were found. First, for raw water with high ammonia concentration(3∼5㎎/L), a large quantity of chlorine was added to get rid of ammonia through breakpoint chlorination. Post-chlorination practice in this case becomes unnecessary because the chlorine residual prior to clear well is sufficiently high in maintaining chlorine residual in distribution system. Second, for the same type of raw water with first case in terms of ammonia content, only small amount of chlorine was added to the water two sites (as pre-chlorine & post -chlorine) to form the combined chlorine as residual chlorine. This type of chlorine practice is called as $quot;chloramination$quot;. Chloramination in Korea is unique in two ways. 1) naturally occurring ammonia was used far ammonia source 2) this was chosen due to the shortage of chlorine capacity not for the control of chlorinated byproducts. Third, for the water which does not contain high ammonia content, dual chlorine addition practice was selected. Pre-chlorination is performed to meet the chlorine demand of raw water. Post-chlorination is performed to maintain the proper residual chlorine in distribution system.

국내 정수장 소독공정 설계 및 운전특성 파악

윤제용(Je Yong Yoon),변석종(Seok Jong Byun),조순행(Soon Haing Cho) 한국물환경학회 2001 한국물환경학회지 Vol.17 No.3

In a nationwide scale, we investigated the characteristics of disinfection facilities & operation practices of the water treatment plants. Disinfection requirement based on the SWTR (Surface Water Treatment Rule) of the U.S. (0.5-log and 1-log Giardia removal) was applied in estimating the compliance, considering only postdisinfection process in clearwells. All of the water treatment plants mainly used the chlorine as a disinfectant and 43 % of those adopted predisinfection. 55∼81% of the water treatment plants failed to satisfy CT value required for the removal of 0.5-log Giardia., depending upon the retention time based on design or operation. The plants showing the high non-compliance rate were largely than 50,000 ㎥/day. One of the main reasons was that the effective residence time was not achieved due to the lack of baffle wall in clearwells. Seventy plants, which failed to comply with the CT requirement for 2-log virus inactivation, were found.

금강지역 정수장 원수에서 Cl2/NH3 에 따른 THMs 및 TOXs 생성특성에 관한 연구

윤제용(Je Yong Yoon),변석종(Seok Jong Byun),이상덕(Sang Duk Lee) 한국물환경학회 1998 한국물환경학회지 Vol.14 No.4

Chlorine is currently being used for the disinfection process in nearly all domestic water treatment plants. Trihalomethanes(THMs) and a lot of chlorinated disinfection byproducts(DBPs) are inevitably produced as a result of chlorine use. The chlorinated DBPs other than THMs are hard to measure and regulate individually. Total organic halides(TOXs) which indicate the sum of chlorinated DBPs may be used as a process control variable for the control of DBPs. In this study, the formation characteristics of THMs and TOXs as a function of the ratio of Cl₂ to NH₃-N in two types of raw water which have the different characteristics of ammonia concentration were investigated. The breakpoint chlorination of the drinking water treatment plants was simulated to represent the characteristics of DBPs formation. Breakpoint chlorination curves with naturally occurring ammonia were not significantly different, when compared to those with chemical ammonia. The breakpoint was observed at Cl₂/NH₃-N ratio of 7.0∼7.7. When Cl₂/NH₃-N ratio was below 5, where chloraminations were practiced, THMs & TOXs formation were low, becoming up to 8㎍/L and 78㎍/L respectively. Below Cl₂/NH₃-N ratio of 5, THMs formation was almost identical regardless of water quality presumed and the source of ammonia, while TOXs formation slightly reflected water quality. On the other hand, when the ratio of Cl₂to NH₃-N was above 7.5, the level of THMs & TOXs formation increased significantly, becoming up to 36㎍/L and 259㎍/L respectively. It was found that the overall level of THMs and TOXs formation was not high, considering the organic content and the high chlorine dose applied. The implication of this DBPs formation characteristics could be enormous for the regulation policy of DBPs. THMs that is only the regulated DBPs explained about 8∼14% of TOXs.

CT 값에 의한 정수장의 소독능 평가

윤제용(Je Yong Yoon),변석종(Seok Jong Byun),이상덕(Sang Deok Lee),석관수(Kwan Su Seok) 한국물환경학회 1998 한국물환경학회지 Vol.14 No.4

Disinfection process in water treatment plants is one of the most important step in order to inactivate waterborne disease. However, what is the necessary disinfection which has to be achieved in water plants was not properly established in Korea. In this study, we introduced the concept of CT values and evaluated CT in several water treatment plants to propose reasonable guidelines of necessary disinfection capabilities. The concept of CT was referred to the SWTR(Surface Water Treatment Rule) which is current US-EPA regulation. The necessary disinfection capability is expressed by CT which may be variable depending on the type of disinfectant, temperature, and pH etc. C is the concentration of disinfectant in the effluent of clearwell and T(=T-10) is the detention time at which 90% of the water passing through the unit is retained within the basin. Total of 8 water treatment plants(CJ, SS, BS, KG, BW, YC, KC, YJ) were intended to investigate the necessary disinfection capability in clearwell. For two of them, tracer study to find out T_(10) was not possible due to the unavailability of the port of chemical addition in the clearwell. It was found that T-10/T were varied widely from 0.2 to 0.5 even though all the clearwell in water treatment plants investigated were not baffled. For reference, T_(10)/T of 0.1 were given for unbaffled clearwell in terms of US-EPA recommendation. Considering the operation condition of plants and water quality characteristics at the time of study, 6 of water treatment plants successfully met the necessary disinfection capability based on 90% giardia removal. However, under the scenario of worst case which can be anticipated year round, nearly all the water treatment plants failed to meet CT requirements. Therefore, the necessities for adjusting disinfection process to the condition of various water quality were raised.

연구논문 - 에너지 , 환경분과 : 음용수에서 생성되는 염소계 소독부산물 중 HAAs 생성특성에 관한 연구

윤제용,변석종 ( Je Yong Yoon,Seok Jong Byun ) 한국공업화학회 1997 한국공업화학회 연구논문 초록집 Vol.1990 No.3

전염소 투입 및 정수지 구조가 정수장 총소독능에서 갖는 중요성 평가

윤제용(Je Yong Yoon),변석종(Seok Jong Byun),최유식(Yu Sik Choi) 한국물환경학회 2001 한국물환경학회지 Vol.17 No.3

Disinfection is one of the most important processes in water treatment plants since it protects consumers from waterborne diseases. In Korea, chlorine which is most frequently used as a disinfectant is generally applied in two ways: prechlorination and postchlorination. Postchlorination is to supply chlorine to the influent of a clearwell. While, prechlorination is to add chlorine to rapid mixing chamber or water intake in plants. Major disinfection reaction occurs in the step of post chlorination. Therefore, frequently, prechlorination is not counted on in evaluating disinfection credit. This study was conducted to evaluate the importance of prechlorination and the existence of baffling wall in clearwell with the United States disinfection requirement(Surface Water Treatment Rule). Eight water plants were considered. Yoon`s classification(1997) was selected in classifying the prechlorination practice in water treatment plant. It was found that most of the prechlorination practices performed in water plants(three out of four types) were not important in gaining any significant disinfection credit. One prechlorination practice conducted to remove ammonia in raw water became significant in meeting the disinfection requirement. Despite the existence of baffling walls of clearwell, T_(10)/T varied considerably in the range of 0.3-0.6, indicating that the existence of baffling wall itself does not guarantee the goodness of plug flow characteristics. For some plants, T_(10)/T were lower than that of US-EPA conservative recommendation which is considered when tracer test could not be performed.

국내 상수원수의 유기물 특성에 따른 소독부산물 생성능

염철민,변석종,조순행,윤제용 대한상하수도학회 2003 상하수도학회지 Vol.17 No.1

This study was conducted to investigate the characteristics of disinfection by-products formation potential (DBPFPs) of dissolved organics. Dissolved organics in raw water were separated into two fractions ((1) hydrophilic and (2) hydrophobic) for the measurement of DBPs. Three types of DBPs (trihalomethanes (THMs), haloacetic acids (HAAs), and total organic halides (TOX)) were measured at 3days and 7days incubation time. Sample waters were collected from the Han River and the Wonchun Reservoir. Two major findings are as follows. First, THMFPs/DOC, HAAFPs/DOC and TOXFPs/DOC in the hydrophilic organic component had a level of lower value than those of the hydrophobic organic component. Brominated THMs and bominated HAAs were not found in the chlorinated hydrophobic organic component. Second, the magnitude of HAAFPs/DOC were higher than that of THMFPs/DOC in both hydrophilic and hydrophobic organic components. This results support the reported observation that HAAs formations were higher than that of THMs in chlorinated drinking water. THMFPs and HAAFPs comprised 53-91% of TOXFP.