• 상하수도학회지
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• 제24권2호
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• pp.231-236
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• 2010

A compressible media filtration process with synthetic fiber media was studied for combined sewer overflows (CSOs) treatment. Since the operation performance of fiber media filtration was dependent on the pattern of CSOs, the flow rate of CSOs was investigated and it was characterized by a big fluctuation. Thus, in this study, the fiber media filtration process was tested with wide range of filtration velocity. The removal efficiency was proportion to the increase in compressibility. As the filtration velocity was increased, the treatment efficiency was decreased and consequently leveled off when the velocity exceeded 750 $m^3/m^2$/d. An exponential equation was introduced to express the relationship between the removal efficiency and up-flow velocity. At columm test, six repetition of filtration and backwash cycle did not after the filtering velocity under the constant pressure condition.

• 상하수도학회지
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• 제25권5호
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• pp.751-757
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• 2011

The monitoring technique based on electrical conductivity (EC) can provide researchers with some advantages in maintenance management and is cost-effective as compared with existing CSOs monitoring. In this study, the flow rate estimation using EC data was executed in two sites where storm overflow chamber had installed. In the result of A-site, R2 of second order multinomial between dilution ratio of EC and observed flow rate was showed the range of 0.68 ~ 0.77. And $R^{2}$ of B-site was 0.62 ~ 0.81. On the other hand, cumulative frequency of A-site was 43.4 ~ 52.2% in the relative error level of under 20%. And B-site was 10.1 ~ 46.5%. The flow rate estimation formula was improved through consideration of some parameters including antecedent dry days and rainfall duration. And difference between estimated flow rate and observed flow rate in total rainfall event was very small.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.1199-1203
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• 2005

Combined sewer overflows(CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available(which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a contiunous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban dranage system used analytical Probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics or the subject area using analytical Probabilistic model. Runoff characteristics manifasted the unique characteristics of the subject area with the infiltration capacity of soil and recovery of depression storage and was examined appropriately by sensitivity analysis. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range 3xDWF(dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a dicision of storage volume for CSOs reduction and water quality protection.

• 대한환경공학회지
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• 제28권6호
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• pp.654-660
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• 2006

본 연구에서는 대전천에 위치한 오정천지역의 소유역을 대상으로 CSOs 배출특성에 관한 모델링을 실시하였다. SWMM을 이용하여 대상유역에서 $2001{\sim}2004$년까지의 연간 유량, 수질, 및 부하량 변화에 대하여 모의를 실시하였다. 모의결과에 의하면, 강우에 의해 발생된 SS 유출부하량은 강우가 집중되는 $7{\sim}8$월에 가장 높게 나타났으나, 이때 강우의 증가에 비하여 부하량의 증가는 크지 않았는데 이는 강우가 잦은 $7{\sim}8$월에는 짧은 건기일수로 인하여 유출수의 SS농도가 낮아졌기 때문이다. $2001{\sim}2004$년 동안의 유량과 수질을 기초로 유출부하량을 산정한 결과 SS가 연간 하천에 미치는 부하량은 건기에 9.3%, 우기에 90.7%로 우기시에 미치는 영향이 매우 큰 것으로 나타났다. 우기시에 우수토실에서 월류를 통해 유출되는 CSOs는 38.4%, 차집관거로 차집 되어 하수처리장 방류구를 통해 방류되는 부분은 61.6%로 산정되었다.

• 한국물환경학회지
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• 제22권6호
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• pp.1068-1074
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• 2006

For receiving water quality protection a control systems of urban drainage for CSOs reduction is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as storm-water detention storage is highly dependant on the temporal variability of storage capacity available as well as the infiltration capacity of soil and recovery of depression storage. For the continuous long-term analysis of urban drainage system this study used analytical probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model has evolved that offers much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics of the subject area using analytical probabilistic model. Runoff characteristics manifested the unique characteristics of the subject area with the infiltration capacity of soil and recovery of depression storage and was examined appropriately by sensitivity analysis. This study presented the average annual CSOs, number of CSOs and event mean CSOs for the decision of storage volume.

• 상하수도학회지
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• 제18권3호
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• pp.320-330
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• 2004

Most of domestic city is served combined sewer system among various sewer system like as separate sanitary, combined sewer system and storm sewers. During the wet weather, sewer and rainfall have been overflowed because it is over capacity of the combined sewer system; that is called combined sewer overflows(CSOs) This research was carried out to investigate runoff characteristics of combined sewer and to evaluate the effective CSOs volume in Hong-Chun gun. During wet weather, SS load of first rainfall at H-1, H-2, and H-3 were 600kg/event, 370kg/event, and 289kg/event, respectively. 55 load of second rainfall were 216kg/event, 113kg/event, and 37.2kg/event. When the first rainfall, event mean concentrations(EMCs) at each site were 702mg/L, 816mgjL and 861.5mg/L. The second rainfall's event mean concentrations(EMCs) were 99.9gm/L, 161.9mg/L, 103.6mg/L. Rrst flush coefficient b at each site were 0.237,0.166, and 0.151. When the first rainfall, the flow containing 80% of pollutant mass of CSOs at each site were 0.55, 0.23, 0.48 in first rainfall, respectively. The case of second rainfall were 0.79, 0.83, 0.81. Most of all, characteristics of rainfall like as analysis of first-flush, CSOs volume, pollutant loadings is investigated to decide intercepted volume for control of CSOs.

• 한국물환경학회지
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• 제23권4호
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• pp.490-497
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• 2007

A Combined sewer overflows (CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available (which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a continuous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban drainage system used analytical probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics of the subject area using analytical probabilistic model. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range $3{\times}DWF$ (dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a decision of storage volume for CSOs reduction and water quality protection.

• 한국산학기술학회논문지
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• 제15권5호
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• pp.3270-3278
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• 2014

도시배수시스템에서는 초기유출수(first flush)에 의한 하천오염이 심각한 문제로 대두되고 있다. 이는 강우발생시 강우에 의해 도시지역의 비점오염원들에 의해서 오염물이 하수관거로 유입되고 한정된 하수처리장의 용량으로는 제대로 처리하지 못하는 월류수에 의해 하천의 수질이 악화되기 때문이다. 대상유역으로 선정한 경기도 구리시 돌다리분구는 합류식 관거로 이루어져 있어 우기시 강우에 의한 월류가 발생할 확률이 높다. 월류에 의해 인근 왕숙천의 수질오염이 가중될 우려가 있어 적절한 처리시설의 설치가 필요하였다. 기존의 CSOs 설계에서는 강우의 최대치를 이용하여 설계가 연구되었다. 그러나, 강우의 최대치를 이용한 설계는 시설의 과다계획으로 이어져 많은 예산낭비를 초래할 수 있으며, 처리시설의 적정규모를 산정하지 못한다. 본 연구에서는 강우특성을 분석하여 매개변수들을 산정하고 이에 따른 유출분석을 실시하였다. 또한 위험도를 고려한 강우-유출분석을 이용하여 유출량을 계산하였다. 유출량을 포함한 유출특성에 의해 월류특성을 분석하였다. 왕숙천 BOD 오염농도를 기준으로 설계하기 위해 하수처리장 용량별 처리시설 요구효율을 산정하였으며 현재 하수처리장의 하수처리를 고려하여 간이 CSOs 처리시설의 효율을 71.48%로 하여 설계하였다.

• 한국물환경학회지
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• 제27권1호
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• pp.36-43
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• 2011

This study is selected two points of combined sewer that occurred Fish Kill after first flush, that analyzed generation of pollutants and stream runoff generation of combined sewer overflows (CSOs) as fine weather and rainfall. In addition, this study was to analyze the relationship between CSOs and sediments, to propose measures to reduce the sediment relevant with CSOs and rainfall runoff from entering sewage treatment plants and measures for discharged directly into streams when indicate relatively good water quality after overflow. Sediments in combined sewer system was discharged about 50~80% as overflows during rainfall and we can reduce the amount of the CSOs at least 50% or more if the sewer does not exist in the sediments because of the amount of discharge about the amount of intercept has been investigated by 3~5 times. Because of velocity at sediment interval in sewer is very low, sewage velocity of about 3~5 times as much as it can increase the amount of sediment can be reduced if the separation wall is installed. Effective control of BOD overflow load is respectively 77.5%, 75.8% at first point, second point by the separation wall is installed. Drainage area greater than area in this study or many combined sewer overflows region is increased the more effective control of separation wall. Turbidity to measure changes in water quality of overflows can be used as an factor to control the intercept flows because the intercept flows(3Q) after the first flush has lowered removal efficiency and increases the operational load of sewage treatment plants. Sewage water quality after a overflow when the reasonable turbidity was measured at this point flows to excluded intercept flow(1Q) can be discharged to stream.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.241-241
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• 2021

Recent developments recommend the use of SSS to prevent combined sewer overflows and reduce excessive pollutant deposition in the receiving waters; however, other studies also suggest that SSS have minimal or no advantage over CSS in terms of reducing the pollutant loads being discharged in natural waterways. This study was conducted to evaluate the effectiveness of employing SSS in improving the water quality of the rivers in Okcheon-gun, South Korea. The former combined sewer outfalls (CSOs) were monitored to determine the presence of illicit connections or leaks in the newly-established SSS. Dry and wet-day monitoring was conducted alongside the collection of water samples on 14 points along the reach of the rivers and four former CSOs to determine water quality changes and patterns of pollutant loading. Among the 34 former CSOs in the study area, eight former CSOs exhibited dry-day discharges, implying the possibility of having illicit connections, leaks, or illegal wastewater discharge in the system. Moreover, relatively high biochemical oxygen demand (BOD) chemical oxygen demand (COD) concentrations, ranging from 4.8 mg/L to 24.9 mg/L and 6.4 mg/L to 10.1 mg/L, respectively were observed on three out of the four monitored CSOs. Fluctuations in the pollutant concentrations in the different monitored points along the river was also observed due to the presence of pipes discharging polluted water. Ultimately, further studies are necessary to identify the sources of dry-day discharges in the CSOs to successfully improve the water quality of the rivers in the area.