• Journal of Environmental Impact Assessment
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• v.18 no.2
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• pp.59-67
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• 2009

Water quality of the Lake Youngrang in the Sokcho City is eutrophic. Jangcheon is the largest inflow source to the lake. Major pollutant sources are stormwater runoff from resort areas and various land uses in the Jangcheon watershed. A storm sewer on the southern end of the lake is also an important pollution source. In this study, water quality modelling for Lake Youngrang was carried out considering the rainfall-runoff pollution loads from the watershed. The rainfall-runoff curves and the rainfall-runoff pollutant load curves were derived from the rainfall-runoff survey data during the recent 4 years. The rainfall-runoff pollution loads and flow from the Jangcheon watershed and the storm sewer were estimated using the two kinds of curves, and they were used as the flow and the boundary data of the WASP model. With the measured water quality data of the year 2005 and 2006, WASP model was calibrated. Non-point pollution control measures such as wet pond and infiltration trench were considered as the alternative for water quality management of the lake. The predicted water quality were compared with those under the present condition, and the improvement effect of the lake water quality were analyzed.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.418-424
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• 2004

An abrupt high pollution loads in combined sewer systems is believed to be caused by first flushing actions and the resuspension of sediments deposited in sewers. Therefore, pollution loads in each flow regulator have a different tendency. This systems control intercepting flow in each flow regulator using water quality and water level. A desired quantity of intercepting flow was adjusted and the necessary slide position for a constant intercepting is calculated by Optimization programming. This systems make it possible to reduce pollution loads caused by CSOs to water body, may be alternative for the stable operation of STP through improving water quality to STP.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.622-631
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• 2014

The purpose of this research was to find a proper disposal rainfall extent to improve water quality. SWMM was applied to select catchment area and tested first flush load and rainfall extent. BOD 40mg/L was selected to dispose the first flush and sewer overflow with the same as the criteria of Sewerage Act. Design rainfall, BOD load ratio of first flush sewer overflow, and the ratio of disposal flow were analyzed under various rainfall distribution. BOD load and design rainfall to treat overflow in situation of first flush extent with 4.3~17.4% were 56~87% and 3.8~6.8 mm/day, respectively. In urban area, first flush loads were not correspond to land activities, but tend to increase with increasing rainfall amount and drainage area. The more the distribution of rainfall is similar to Huff-frontal or central distribution of rainfall, the more increase the first flush loads.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.980-987
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• 2012

Nonpoint source pollution causes leaks and overtopping, depending on the state of the sewer network as well as aggravates the pollution load of the aqueous water system as it is introduced into the sewer by wash-off. According, the need for efficient sewer monitoring system which can manage the sewage flowrate, water quality, inflow/infiltration and overflow has increased for sewer maintenance and the prevention of environmental pollution. However, the sewer monitoring is not easy since the sewer network is built in underground with the complex nature of its structure and connections. Sewer decontamination mechanism as well as pipe network monitoring and fault diagnosis of water network system on system analysis proposed in this study. First, the pollution removal pattern and behavior of contaminants in the sewer pipe network is analyzed by using sewer process simulation program, stormwater & wastewater management model for expert (XP-SWMM). Second, the sewer network fault diagnosis was performed using the multivariate statistical monitoring to monitor water quality in the sewer and detect the sewer leakage and burst. Sewer decontamination mechanism analysis with static and dynamic state system results showed that loads of total nitrogen (TN) and total phosphorous (TP) during rainfall are greatly increased than non-rainfall, which will aggravate the pollution load of the water system. Accordingly, the sewer outflow in pipe network is analyzed due to the increased flow and inflow of pollutant concentration caused by rainfall. The proposed sewer network monitoring and fault diagnosis technique can be used effectively for the nonpoint source pollution management of the urban watershed as well as continuous monitoring system.

• Journal of Wetlands Research
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• v.11 no.1
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• pp.75-82
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• 2009

The regulation of emission concentration for stream water qualities doesn't control quantitative increase on pollution loads, it has limits for improvement of water qualities. Total water pollution load management system(TMDL) can control the total amount of pollutant in waste water which is allowed to assign and control the total discharged pollutant loads in a permissible level. When it comes to generated wastewater value of TMDL system, there is difference between calculated value based on individual pollutant unit load and observed value. Calculated sewer inflow, calculated sewer outflow, measured sewer inflow, and measured sewer outflow at dry season are $26,460.9m^3$/d, $17,778.6m^3$/d, $17,106.1m^3$/d and $19,033.9m^3$/d respectively, Calculated sewer inflow, calculated sewer outflow, measured sewer inflow, and measured sewer outflow at rainy season are $49,512.2m^3$/d, $18,628.7m^3$/d, $30,918.2m^3$/d, $19,700.7m^3$/d respectively. This result presents the necessity to acquire the precise observed data to fulfill the efficient TMDL system.

• Journal of Wetlands Research
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• v.20 no.3
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• pp.219-226
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• 2018

Interceptor sewer is installed underground near to the river side mostly ofstate-owned land and the management efficiency of public sewage disposal facilities is decreasing as too much infiltration/inflow(I/I) and river flow to interceptor sewer are caused by broken or deteriorated sewer. This also affects the sewer pipeline project and decreases its efficiency. Therefore, the aim of this study is to investigate interceptor sewer which has influence on the reduction of the project effect. The investigation were performed for three study areas. The study includes the investigation of current condition of interceptor sewer(sewer extension, pipe diameter, pipe type, installed year, installed locations, etc), investigation of inside of sewer by CCTV accompanied by pumping and dredging works where required, investigation of inside of manholes by eyes, calculation of pollutant load using the results of investigation of flow quantity and quality. Multipoint investigations were simultaneously performed for flow quantity at confluence area and other investigations were also performed for flow quantity and BOD for interceptor sewer and comparison of pollutant load, investigation of infiltration/inflow(I/I) caused by deterioration of interceptor sewer. As the result of the study, a main reason for reduced effect of sewer pipe improvement project was analyzed as the low-density sewage and I/I in public seweage treatment Facility due to deteriorated and unmanaged interceptor sewers.

• Membrane and Water Treatment
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• v.11 no.1
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• pp.49-57
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• 2020

The effect of Combined Sewer Overflow on the river system was investigated throughout three preliminary field tests and three main ones. As a result of the study, Combined Sewer Overflow did not affect water qualities on the main stream since the concentration of the main stream did not significantly changed during rainfall events although the water quality of tributaries has rapidly deteriorated due to the influence of the Combined Sewer Overflow during rainfall events. The main cause of the result is that the flow rate of the tributaries is considerably lower than that of the main stream, so that the tributaries with deteriorated water quality during rainfall events did not significantly affect the quality of the actual main stream. Therefore, the water quality of the Kumho River is more affected by the wastewater treatment facilities that discharges water continuously to the main stream than pollutants from non-point pollution sources during rainfall events. As a result, managements for discharges from wastewater treatment facilities should be strengthened in order to improve the water quality of the river.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.29-37
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• 2017

To estimate pollution sources in the watershed with various industries, the simulation of contamination route and distribution of 2-methyl-4,6-dinitriophenol(DNOC) were performed with a numerical model Hydro Geo Sphere. This study was performed calculations of the load using the measured concentration and simulated flow rate. And, the river was divided by the sampling sites at the mainstream, and the contribution rate at downstream sampling sites was calculated for each section. The results showed the concentration of the downstream sampling sites were decided by the concentration of upstream sites, and the contribution rates of the tributaries were calculated below 10%. The results also showed that the impact of the potential sources in Section 1(Geumho1 ~ Geumho2) and Section 5(Geumho5 ~ Geumho6) was larger than in the other area. In Section1 and Section5, It seemed to require detailed investigation.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.982-990
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• 2006

Generally CSOs (Combined Sewer Overflows) are regarded as one of the most serious nonpoint pollution source in the urban watershed, Particularly, the water quality of the Oncheon stream is seriously affected by CSOs because the capacity of interception sewer system connected to the Suyoung wastewater treatment plant is too small to intercept most storm water discharges. The objective of this study is to evaluate the effect of nonpoint source on an urban stream with regards to combined sewer system and separate sewer system using GIS (Geographic Information System) and SWMM (Storm Water Management Model), and to provide an insight for the management of urban stream water quality. In order to consider the effect of CSOs on the receiving water quality, the flow divider element in SWMM was applied. The model calibration and verification were performed by the measured data of quantity and quality on the Oncheon stream. The quantity data acquired from the Suyoung wastewater treatment plant were also used for this procedure. In case of separate sewer system, the modeling results showed the increased tendency in streamflow compared with the combined system in dry weather, In addition, the water quality is remarkably improved in rainfall events at the separate condition. The results imply that the construction of separate sewer system should be taken into first consideration to restore the quality and quantity of water in urban streams.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.85-93
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• 2021

Sewage separation which often involves installing a new pipe to separate wastewater flow from stormwater runoff flow can be costly and depends highly on its feasibility in a site. To be able to develop a potentially more economical alternative that can also lessen major road traffic disturbance during this process, a different approach where a smaller sewage separator pipe is installed inside an existing combined sewer pipe was investigated. A small-scale of a box sewer and the proposed sewage separator pipe was constructed in the laboratory to observe and compare the deposition of solids and other solid-associated major pollutants at different flow rates. In addition, three-dimensional flow simulations considering five different scenarios were conducted using Ansys Fluent to observe the effect of the proposed sewage separator pipe to the hydraulic flow if installed inside the combined sewer pipe. Results revealed that the deposition of TSS, TCOD, TN, and TP were reduced by at least 60% when the wastewater was conveyed by the sewage separator pipe instead of the combined sewer pipe. Moreover, the flow simulations conducted showed that there was little to no major disturbance in hydraulic flow and velocity distribution when the sewage separator was installed inside a straight pipe and even at pipe transitions such as intersections, turns, and drop in elevation. Considering the pipe dimensions and the results of the study, the proposed approach can be promising in terms of reduction in pollutant deposition without a major effect on the hydraulic flow. Further investigation and cost-analysis should be done in the future to support these preliminary findings and help alleviate the problems caused by combined sewer overflows by introducing an alternative approach.