• 상하수도학회지
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• 제27권1호
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• pp.1-10
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• 2013

Major issues in water supply service have changed from expansion of service area to improvement of service quality, i.e., water quality and safety, and early response to emergency situation. This change in the service concept triggers the perceptions of limitation with the current centralized water supply system and of necessities of decentralized (distributed) water supply system (DWSS), which can make up the limitations. DWSS can reduce the possibility of water supply outage by establishing multiple barriers such as emergency water supply system, and secure better water quality by locating treatment facilities neighboring consumers. On the other hand, fluctuation of water demand will be increased due to the reduced supply area, which makes difficult to promptly respond the fluctuating demand. In order to supplement this, hybrid water supply system was proposed, which combined DWSS with conventional water supply system using distributing reservoir to secure the stability of water supply. The Optimal connection point of DWSS to existing water supply network in urban area was determined by simulating a supply network using EPANET. Optimal location of decentralized water treatment plant (or connection point) is a nodal point where changes in pressure at other nodal points can be minimized. At the same time, the optimal point should be selected to minimize hydraulic retention time in supply network (water age) to secure proper water quality. In order to locate the point where these two criteria are satisfied optimally, Distance measure method, one of multi-criteria decision making was employed to integrate the two results having different dimensions. This methodology can be used as an efficient decision-support criterion for the location of treatment plant in decentralized water supply system.

• 상하수도학회지
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• 제27권6호
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• pp.679-687
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• 2013

Although stable and safe drinking water supply to the customers is a basic function of multi-regional water supply systems in Korea, most systems have their vulnerabilities in emergency time due to the branch-type. Application of connections from the other water supply system can provide a solutions for these tentative problems. This paper describes reduction planning of water supply accidents that can minimize a service interruption to customers in multi-regional water supply system by connecting pipe lines between local water supply systems in Mokpo city areas. The result of this study shows that Juam dam multi-regional water supply systems can cover all of the water shortage in southern parts of Jeonnam multi-regional water supply systems by transmitting water through connected pipes between local networks. This can be effective to supply water interactively in various contingencies, when a pipe line accident occurs in southern area of Jeonnam multi-regional water supply systems. On the contrary, southern area of Jeonnam multi-regional water supply systems can cover 99.5 %($62,500m^3/day$) of the water shortage of Juam dam multi-regional water supply systems when service interruptions caused by various pipe accidents occur in the system.

• 상하수도학회지
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• 제35권6호
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• pp.517-531
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• 2021

The water supply facilities of Korea have achieved a rapid growth, along with the other social infrastructures consisting a city, due to the phenomenon of urbanization according to economic development. Meanwhile, the level of water supply service demanded by consumer is also steadily getting higher in keeping with economic growth. However, as an adverse effect of rapid growth, the quantity of aged water supply pipes are increasing rapidly, Bursts caused by pipe aging brought about an enormous economic loss of about 6,161 billion won as of 2019. These problems are not only worsening water supply management, also increasing the regional gap in water supply services. The purpose of this study is to classify hazard evaluation indicators and to rank the water distribution network hazard by cluster using the TOPSIS method. In conclusion, in this study, the entropy-based multi-criteria decision-making methods was applied to rank the hazard management of the water distribution network, and the hazard management ranking for each cluster according to the water supply conditions of the county-level municipalities was determined according to the evaluation indicators of water outage, water leakage, and pipe aging. As such, the hazard ranking method proposed in this study can consider various factors that can impede the tap water supply service in the water distribution network from a macroscopic point of view, and it can be reflected in evaluating the degree of hazard management of the water distribution network from a preventive point of view. Also, it can be utilized in the implementation of the maintenance plan and water distribution network management project considering the equity of water supply service and the stability of service supply.

• 상하수도학회지
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• 제28권6호
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• pp.755-763
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• 2014

In this paper, a System Dynamics(SD) computer simulation model has been developed to assess the effects of developing and providing an alternate water source. A water service index was also developed to estimate the level of overall customer satisfaction on water supply service. Data from the Busan water supply service and the Korea Development Institute regarding the Nak Dong river bank storage development were utilized during the modeling processes. Some important indicators of the system under study were analyzed by the simulations of development of the alternate water source for Busan. The developed SD model and the water service index can be further utilized as a tool that can assess the extent and timing of an additional service improvement project.

• 상하수도학회지
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• 제34권5호
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• pp.311-321
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• 2020

In this study, a model to optimize residual chlorine concentrations in a water supply system was developed using a multi-objective genetic algorithm. Moreover, to quantify the effects of optimized residual chlorine concentration management and to consider customer service requirements, this study developed indices to quantify the spatial and temporal distributions of residual chlorine concentration. Based on the results, the most economical operational method to manage booster chlorination was derived, which would supply water that satisfies the service level required by consumers, as well as the cost-effectiveness and operation requirements relevant to the service providers. A simulation model was then created based on an actual water supply system (i.e., the Multi-regional Water Supply W in Korea). Simulated optimizations were successful, evidencing that it is possible to meet the residual chlorine concentration demanded by consumers at a low cost.

• International Journal of Air-Conditioning and Refrigeration
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• 제11권1호
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• pp.40-49
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• 2003

Dynamic characteristics of water hammer arresters installed in a building water supply system have been investigated numerically by utilizing a commercial code that employs the method of characteristics. Some preliminary results with those arrester models produced in this study agree well with the previously reported. Then, the arrester models have been incorporated into a water supply pipe system of a 59 $m^2$apartment unit constructed by a leading construction company, and their dynamic characteristics have been investigated, especially on the reduction in the water hammer pressure. It is found that the setting of the arresters in the pipe system, which is recommended by the company, may not be proper for reducing the pressure down below 1,082.0 kPa (10.0 kg$g_f$/$cm^2$) when quick-closure valves in the pipe system are closed within 30 ms at the static pressure of 542.6 kPa (4.5 kg$g_f$/$cm^2$). More arresters in the system may be required to meet pressure criteria stated on the related standards and codes.

• 상하수도학회지
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• 제24권1호
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• pp.25-32
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• 2010

Until now, we recognize that water supply is a public sector rather than business sector in Korea. In spite of the general recognition, water supply sector has an important role within the national economy as an industry. This study try to analyze the current status of water supply sector as a industry with input-output analysis. As we expected, water supply sector is still minor as an industry sector. However, this is not because water supply sector is not important as a industry, but because the price of water too low or free. With regard to the water price impacts, our results show that the 10% increasing water price has only increased 0.01% of the general price level, which is neglectable. To have a competitiveness as a industry, water sector should be reevaluated based on its socioeconomic value. Government policy for water supply sector should achieve two purposes; the one is for as a public service, the other is for the setting new paradigm as an industry.

• 경영과정보연구
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• 제36권3호
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• pp.89-111
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• 2017

오늘날의 시대는 블랙골드(black gold)시대를 벗어나 이제 블루골드(blue gold)의 시대가 도래되었다고 할 수 있다. 물에 대한 중요성이 증가되는 가운데, 물 산업의 발전을 위한 지원 및 정책이 제시되고 있다. 물 산업은 공공서비스이지만, 불균형한 공급으로 인한 문제점들이 존재하며 이를 해결하기 위해서 공공서비스의 민영화라는 주제와 관련해 가장 민감하고 관심이 집중된 분야라고 할 수 있다. 우리나라도 이러한 물 산업의 민영화에 대한 주제가 언급되면서 현행 수도법에 근간한 민영화 운영방식 중 하나인 전문기관(한국수자원공사)에 의한 민간위탁이라는 방식으로 공공서비스의 효율성을 높이고자 사업을 진행 중에 있다. 따라서 본 연구에서는 지방상수도 민간위탁 운영을 실행 중인 18개 지역의 위탁사업소들을 대상으로, 2012년부터 2014년까지의 데이터를 바탕으로 하여 민간위탁운영에 대한 효율성 및 생산성 분석을 실시하고자 한다. 본 연구의 효율성 분석결과, 3개년 동안 18개의 위탁기관 중 10개 기관이 효율적인 기관으로 나타났으며 생산성 변화에 대한 분석을 실시한 결과, 1기(2012-2013년)에서 2기(2013-2014년)로 넘어가는 동안 생산성이 감소된 것을 확인할 수 있었다. 이러한 생산성에 영향을 미치는 원인은 누수율과 원수의 유효이용률로 선정하였고 누수율의 경우 생산성에 부(-)의 영향을 미치는 것으로 나타났고 원수의 유효이용률의 경우, 생산성에 정(+)의 영향을 미치는 것으로 나타났다. 따라서 본 연구는 현 수도사업의 문제점을 해결하기 위한 해결책에 대한 효율성과 생산성을 분석하였다는 점에서 기존의 수도사업과 관련된 연구들이 제시하지 못한 시사점을 지니고 있다고 할 수 있다.

• 상하수도학회지
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• 제31권6호
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• pp.587-597
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• 2017

This study aimed to develop a method to optimize residual chlorine concentrations in the process of providing water supply. To this end, this study developed a model capable of optimizing the chlorine input into the clearwell in the purification plant and the optimal installation location of rechlorination facilities, and chlorine input. This study applied genetic algorithms finding the optimal point with appropriate residual chlorine concentrations and deriving a cost-optimal solution. The developed model was applied to SN purification plant supply area. As a result, it was possible to meet the target residual chlorine concentration with the minimum cost. Also, the optimal operation method in target area according to the water temperature and volume of supply was suggested. On the basis of the results, this study derived the most economical operational method of coping with water pollution in the process of providing water supply and satisfying the service level required by consumers in the aspects of cost effectiveness. It is considered possible to appropriately respond to increasing service level required by consumers in the future and to use the study results to establish an operational management plan in a short-term perspective.

• 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.