• 상하수도학회지
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• 제13권2호
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• pp.95-104
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• 1999

A simulation of water hammer, introduced by abruptly varied motion of a pumping machine, was performed at a one of typical pumping station in Korea. Impact of hydraulic structure such as check valve, pressure relief valve and air valve in mitigating water hammer effect was estimated gradually. Method of characteristic was employed for the effective calculation of discharge and head. The relationship between various hydraulic structures and flow was properly integrated on the base of the method of characteristic. The methodology in this approach can provide significant contribution in decision making procedure for the design of hydraulic structure at a typical pumping station in Korea.

• 상하수도학회지
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• 제26권6호
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• pp.915-925
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• 2012

On-off control performance of target pumping station was experimented by changing measurement methods for storage level or inflow and operating logic for control system setting. Four scenarios with different measurement methods and operational logic were examined in the Matlab/Simulink environment. Controller's on-off control repetition that was frequent before has been reduced and more effective and stable system operation was found to be possible with the scenarios. Moreover, defensive operation enforced prevention of floods by changing measurement methods enabled economic operation that made an utmost use of storage volumes.

• 상하수도학회지
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• 제25권6호
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• pp.847-859
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• 2011

This paper presents an alarm system for the integrated monitoring and control station of waterworks in Daegu City. An alarm system informs the operator or other responsible individuals about the abnormality in the process so that an appropriate action can be taken. In practice, operators receive far more false and nuisance alarms than valid and useful alarms. Too many false and nuisance alarms can distract the operator from operating the plant, and thus critical alarms may be ignored. This problem can lead to the point that the operator no longer trusts the alarms or even shuts down the whole monitoring system. This paper proposes an efficient method to reduce false and nuisance alarms by prioritizing every fault using the Fault Tree Analysis (FTA) technique. The effectiveness of the proposed method is evaluated with a set of computer simulation under various faulty conditions.

• 상하수도학회지
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• 제26권3호
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• pp.383-397
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• 2012

In this study, a System Dynamics (SD) simulation model for the efficient operations of an industrial water supply system was developed by investigating the feedback loop mechanisms involved in the operations of the system. The system was modeled so that as demand is determined the water supply quantity of intake pumping stations and dams are allocated. The main feedback loop showed that many variables such as the combinations of pump operation, unit electric power(kWh/$m^3$), unit electric power costs(won/$m^3$), water level of water way tunnel, suction pressure and discharge of pumping station, and tank and service reservoir water level had causal effects and produced results depending on their causal relationship. The configurations of the model included an intake pumping station model, water way tunnel model, pumping station model (including the tank and service reservoir water level control model), and unit electric power model. The model was verified using the data from the case study industrial water supply system that consisted of a water treatment plant, two pumping stations and four dams with an annual energy costs of 5 billion won. It was shown that the electric power costs could have been saved 7~26% during the past six years if the operations had been based on the findings of this study.

• 상하수도학회지
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• 제25권3호
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• pp.349-357
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• 2011

This study has an objective to estimate effect on water-quality enhancement by removal of contaminated river-bed material using a two-dimensional numerical modeling in the Seonakdong River, the Pyunggang River and the Maekdo River. RMA2 and RMA4 models were used for flow and contaminant transport simulation, respectively. After the analysis of the effects of flow restoration plan for the Seonakdong River system made by Lee et al (2008), simulation have been performed about scenarios which contains operations of the Daejeo Gate, the Noksan Gate, the Makdo Gate (on planning), and the Noksan Pumping Station. Because there is no option for elution from bed sediment in the RMA4 model, a simple technique has been used for initial condition modification for elution. The analyses revealed that the effect on water quality improvement due to dredging of bed sediment seemed to be less than 10 % of the total effect. The most efficient measure for the water quality improvement of the river system was the linked operation of water-gates and pumping station.

• 한국미생물·생명공학회지
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• 제32권3호
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• pp.265-270
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• 2004

하수 중계펌프장에서 발생되는 악취를 효율적으로 저감할 수 있는 기술로 4가지 기술(활성탄 흡착법, 약액세정법, 지렁이 분변로를 이용한 탈취법, 바이오필터법)의 탈취 효율과 경제성을 조사하였다. PU 바이오필터와 활성탄 흡착법의 평균탈취 효율은 98% 이상이었으나, 지렁이 분변토 바이오필터와 약액세정법은 60-80%의 탈취율을 보였다. PU 바이오필터 탈취 성능은 악취가스의 체류시간이 4-36초에서 체류시간과 무관하게 약 98-99%로 매우 안정적이었고, 최대 탈취능은 으로 평가되었다. $1.6${\times}$10^{ 7}$ $OUm^{-3}$$h^{-1}$ PU 바이오필터와 활성탄 흡착법의 탈취비용을 조사하였다. 악취 강도가 증가함에 따라 활성탄 흡탁법의 운전비는 선형적으로 증가하였지만 바이오필터법은 약간 증가하였다. 바이오필터의 초기 시설비의 비용이 활성탄 흡탁법의 2배 이상이었지만 운전비가 활성탄 보다 아주 저렴한 것으로 평가되었다. 결론적으로 탈취효율과 경제성이 우수한 생물여과법이 가장 유망한 기술로 평가되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.540-545
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• 2006

The objective of the study is to assess the water quality improvement resulted from the rearrangement of the irrigation water supply systems at Mankyeong River and Ansung Chun basin. There is a mixed type of watershed composed of urban and rural areas in the region. The water intake facilities for agricultural use such as reservoir, weir and pumping station are generally located at upstream river where the water quality maintains relatively clean. However, this study focuses on moving the water intake to downstream and rearranging the irrigation water supply system, then investigating how effective they are for water quality improvement in the river. When the water intake is moved downstream, the stream flow is increased as much as the amount of irrigation water that is to be taken upstream. The augmented flow which is frequently referred to as environmental flow can function as dilution water for improving the quality of polluted water that is originated from the wastewater in tributaries.

• 상하수도학회지
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• 제19권4호
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• pp.487-496
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• 2005

Chlorine bulk decay tests were carried out by bottle test under controlled conditions in a laboratory. Experiments were performed at different temperatures: $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and the water temperatures when samples were taken from the effluent just before entering to its distribution system. 38 bulk tests were performed for water of Al (water treatment plant), 4 bulk tests for A2 (large service reservoir), and A3(pumping station). Residual chlorine concentrations in the amber bottles were measured over time till about 100 hours and bulk decay coefficients were evaluated by assuming first-order, parallel first-order, second-order. and $n^{th}-order$ reaction. The $n^{th}-order$ coefficients were obtained using Fourth-order Runge-Kutta Method. A good-fit by the average coefficient of determination ($R^2$) was first-order ($R^2=0.90$) < parallel first-order ($R^2{_{fast}}=0.92$, $R^2{_{slow}}=0.95$) < second-order ($R^2=0.95$) < $n^{th}-order$ ($R^2=0.99$). But if fast reaction of parallel first-order bulk decay were applied to the effluent of large service reservoir with ca. 20 hours of travel time and slow reaction in the water distribution system following the first 20 hours, parallel first-order bulk decay would be best and easy for application of water quality modeling technique.

• 상하수도학회지
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• 제32권2호
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• pp.169-181
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• 2018

For performance analysis of flood prevention projects, this study performed simulation (SWMM) for the five sites where the projects have been completed. The models were constructed using watershed and sewer information of the project sites and were verified using flood records in the past to improve accuracy. In this simulation, the design rainfall data (probability 30~50 years) and the rainfall data in the summer of 2017 were applied. When the design rainfall data was applied to the models, simulation results presented that all the sites were flooded before the projects, but after the projects all the sites were not flooded due to improve discharge capacity. And when the rainfall data in the summer of 2017 was applied to the models, simulation results presented that all the sites were flooded before the projects, but after the projects any sites did not occur flooding in this summer. So if the projects had not been completed, all the sites might be flooded in the summer of 2017. These effects were analyzed as the improvement of discharge capacity due to rehabilitation of sewer, construction of underground tunnel and pumping station, etc. As the results, ratio of sewer that water depth exceed diameter reduced from 52.3~75.8% to 17.1~39.8%.

• 상하수도학회지
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• 제31권2호
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• pp.177-186
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• 2017

This study concerned the analysis on the efficiency of the conversion of water tank type supply system to direct water supply system to examine the feasibility of the conversion, as well as the calculation of optimal conversion range that enables the supply of safe, high-quality water at stable pressure in accordance with the standards of water supply facility. The results of this research showed that when converting water supply system from water tank type supply system to direct water supply system, more nodal points could be properly converted and more reduction of electricity usage was expected in case water pressure rather than residence time was fixed. This means that higher efficacy can be obtained by fixing water pressure when converting water supply system. However, since the number of the locations that received on-spot inspection was small and the electricity usage measured was not exclusively by water supply facility, it is difficult to judge that such reduction of electricity usage accurately represents reduced electricity usage by water supply facility alone. therefore, after having secured on-spot information about a larger number of locations in apartment complexes that have converted water supply system, and utilizing information about electricity usage exclusively by water supply facility, the proposed method of this research could be applied to accurately deducing expected reduction of electricity usage by water supply facilities of various other apartment complexes. It is also considered possible to deduce an effective operation method of water supply system by finding out an area that shows low pressure or low residual chlorine concentration in the optimal conversion range of water supply, followed by estimating the proper location of pumping station or the proper chlorine dosage at the power purification plant that supply water to the target area.