• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.627-635
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• 2006

Combined sewer overflow (CSOs) is a primary diffuse source degrading water quality of urban streams. In this study, CSOs caused by 5 different rainfall events at an urban watershed located in Daejeon city were monitored for the indicator microorganism concentrations. Event mean concentration (EMC) of the indicator microorganisms were: total coliform = $2.46{\times}10^6CFU/100mL$; fecal coliform = $1.01{\times}10^6CFU/100mL$; E.coli = $5.20{\times}10^5CFU/100mL$; and Fecal Streptococci = $6.08{\times}10^5CFU/100mL$. In addition, coliform concentrations were well correlated with suspended solid concentrations and the first flush effects were identified. Settling tests were carried out to estimate removal rate of indicator organisms by sedimentation from CSOs. As microorganisms are discharged in association with suspended solid, ten minutes of settlement can lower 44% of indicator microorganism leading.

• Journal of Korean Society on Water Environment
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• v.31 no.4
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• pp.428-435
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• 2015

This study was carried out to evaluate the performance of a inflow controller for the control of combined sewer overflows (CSOs). Because of the inflow controller could be adjusted manually by predicting the maximum amount of peak flow, the mechanical adjustment of this controller was higher than the existing fixed-type controller in field application. Standardizing the relationship between the flow and the clearance and angle of an inlet cover plate on the inflow conditions can selected to the optimum conditions for the on-site. It was concluded that BOD pollutant loading at the region in which inflow controller was installed had shown the removal efficiency rate of 42%.

• Environmental Engineering Research
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• v.10 no.2
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• pp.62-70
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• 2005

Pollution loading of Combined Sewer Overflows (CSOs) is frequently over the capacity of a wastewater treatment plant (WWTP) receiving the water. The objectives of this study are to investigate water quality of CSOs in Anmyun-ueup, Tean province and to apply Storm Water Management Model to predict flow rate and water quality of the CSOs. The capacity of a local WWTP was also estimated according to rainfall duration and intensity. Eleven water quality parameters were analyzed to characterize overflows. SWMM model was applied to predict the flow rate and pollutant load of CSOs during rain event. Overall, profile of the flow and pollutant load predicted by the model well followed the observed data. Based on model prediction and observed data, CSOs frequently occurs in the study area, even with light precipitation or short rainfall duration. Model analysis also indicated that the local WWTP’s capacity was short to cover the CSOs.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1075-1081
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• 2006

In this research, mortality rates of pathogen indicator microorganisms discharged from various point sources and diffuse sources in urban area were measured. Water samples were taken at domestic sewer, combined sewer overflow, effluent from a wastewater treatment plant, urban river, and sediment of an urban river. Mortality rates of indicator microorganisms in domestic sewer estimated by assuming the first order kinetics at $20^{\circ}C$ were as follows: total coliform = 0.092/day, fecal coliform = 0.185/day, E. coli = 0.252/day, and fecal streptococci = 0.281/day. Sensitivity of mortality rates of total coliform on temperature was estimated as $K_{temp}=K_{20}{\times}1.162^{(temp-20)}$ for the range of $10-20^{\circ}C$. Mortality rates due to sunlight were measured as 1.22-1.59/day while mortality rate due to settling for 40 min were estimated as $9.21{\times}10^3-20.0{\times}10^3/day$.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.935-947
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• 2011

In the era of climate change, the feasibility of a 'multi-functional storage facility' was evaluated in terms of various key performance indices such as flooding prevention effects, urban pollution reduction effects, and rainwater harvesting effects. As a result, the Korea Ministry of Environment introduced a new concept of 'multi-functional storage facility' for sewer flooding prevention and urban non-point pollution reduction. Prior to introducing these infrastructure (a large underground storage facility), the more details were needed to be examined carefully in all of technical aspects of construction and management. It was also well known that the validity of installation of 'multi-functional storage facility' was sometimes weakened because of a low B/C ratio.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.9-14
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• 2008

• Journal of Korean Society on Water Environment
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• v.36 no.3
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• pp.206-219
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• 2020

As urbanization and impermeable areas have increased, stormwater and non-point pollutants entering the stream have increased. Additionally, in the case of the old town comprising a combined sewer pipe system, there is a problem of stream water pollution caused by the combined sewer overflow. To resolve this problem, many cities globally are pursuing an environmentally friendly low impact development strategy that can infiltrate, evaporate, and store rainwater. This study analyzed the expected effects and efficiency when the LID facility was installed as a measure to improve hydrologic cycle and water quality in the Oncheon stream in Busan. The EPA-SWMM, previously calibrated for hydrological and water quality parameters, was used, and standard parameters of the LID facilities supported by the EPA-SWMM were set. Benchmarking the green infrastructure plan in New York City, USA, has created various installation scenarios for the LID facilities in the Oncheon stream drainage area. The installation and maintenance cost of the LID facility for scenarios were estimated, and the effect of each LID facility was analyzed through a long-term EPA-SWMM simulation. Among the applied LID facilities, the infiltration trench showed the best effect, and the bio-retention cell and permeable pavement system followed. Conversely, in terms of cost-efficiency, the permeable pavement systems showed the best efficiency, followed by the infiltration trenches and bio-retention cells.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.949-957
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• 2011

This aim of study was to investigate the characteristics of discharge of pollutants as well as the correlation between flow rate and water quality constituents in a combined sewer system according to the characteristics of rainfall. For the loading rates for each pollutant, the median concentrations of all pollutants except T-N was increased when a CSO took place. The loading rates of BOD, COD, SS, T-N, T-P, Cu and Zn at the CSOs were 328-1255, 25-129, 83-2009, 4-12, 14-51, 5-11 and 5-13 times higher than the DWF (Dry Whether Flow), respectively. Especially, SS loading rate was found to be highest in all pollutants. On the other hand, the range of the first flush coefficient, b for water quality constituents such as BOD, COD, SS, T-N, T-P, Cu and Zn were 0.537-0.878, 0.589-0.888, 0.516-1.062, 0.852-1.031, 0.649-0.954, 0.975-1.015 and 0.900-1.114, respectively. In term of correlation between flow rate and pollutant concentrations, SS concentration was highly correlated to flow rate. However, there was an inverse correlation between EC (Electrical Conductivity) and flow rate because of the high dilution of flow rate. In case of correlation between pollutants, there was a high correlation between SS and T-P.

• Journal of Environmental Science International
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• v.19 no.6
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• pp.747-753
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• 2010

It follows in quality and sewage exclusion method of the investigation objective sector and the Combined Sewer Overflows which is suitable in regional characteristics and the confluence area against the rainfall initially a flow and the medulla and measurement - it analyzes the initial rainfall outflow possibility control plan which is suitable in the domestic actual condition and it proposes the monitor ring plan for the long-term flow and pollution load data accumulation. From the research which it sees the Infiltration water/Influent water and CSOs investigation it passes by the phase of hazard chain and Namwon right time 4 it does not hold reverse under selecting, Measurement it used the hazard automatic flow joint seal Sigma 910 machine and in case 15 minute interval of the I/I, it measured a flow at case 5, 15 minute standing of the CSOs. The water quality investigation for the water leakage investigation of the I/I and the sewage from the point which is identical with flow measurement during on-the-spot inspection duration against 6 items which include the BOD sampling and an analysis, when the rainfall analysis for CSOs fundamental investigation analyzed against 18 items which include the BOD sampling. Consequently, for the optimum interpretation invasion water / inflow water of the this investigation area day average the lowest flow - water quality assessment veterinarian optimum interpretation hazard average per day - lowest flow - it averages a medulla evaluation law department one lowest flow evaluation technique and it selects, it presentation collectively from here it gets, position result with base flow analysis of invasion water / inflow water.

• Journal of Korea Water Resources Association
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• v.48 no.9
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• pp.695-709
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• 2015

The inflow of nonpoint pollution sources due to sustainable development and urbanization is gradually increasing and causes a diversity of water pollution. There are lots of difficulties to find a solution as the problems related to variation of hydrological and natural phenomenon. A differentiated method to estimate the nonpoint pollution sources has been proposed using rainfall and characteristics of urbanization and observed data from sewage treatment districts in the study. The types of nonpoint pollution sources on an assumption of combined sewer system have been classified as three types which are inflow of rainfall, bypass of sewage treatments, and combined sewer overflows from a river. Three types for estimation of nonpoint pollution sources applied more accurately to generate a amount of nonpoint pollution loads. This study is expecting a wide application for effective water resource management on TMDL (total maximum delivery load) unit watershed and sewage treatment districts.