• 상하수도학회지
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• 제29권1호
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• pp.1-9
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• 2015

A combined treatment system using multiple source water is becoming important as an alternative to conventional water supply for small-scale water systems. In this research, combined water treatment systems were investigated for simultaneous use of multi-source water including rainwater, ground water, river water, and reclaimed wastewater. A laboratory-scale system was developed to systematically compare various combinations of water treatment processes, including sand filtration, microfiltration (MF), granular activated carbon (GAC), and nanofiltration (NF). Results showed that the efficiency of combined water treatment systems was affected by the quality of feed waters. In addition, a simply approach based on the concept of linear combination was suggested to support a decision-making for the optimum water treatment systems with the consideration of final water quality.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.524-528
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• 2009

The objectives of this study were to install RCR systems at a typical single family house and a school in Alabama, and evaluate the feasibility and efficiency of using the RCR systems for water harvesting in Alabama. The RCR systemswere equipped with a control system and a CR10X data logger to monitor the system operation and to collect data on precipitation, temperature, overflow, water depth in the storage tank and daily uses of toilet flushing. Daily average water use of the home for toilet flushing was 95 liter and 2100 liter was used at the school during the school days. Rainwater harvesting efficiency was 83.3 and 89 percent and RCR use efficiency was 18 and 98 percent from the home and the school, respectively. A computer program was developed to estimate potential effectiveness of RCR systems. From the analysis result with 10 years rainfall data, a total of 67,000 liters of rainwater could be harvested for domestic uses from a typical single family house which supplies 190 liters per day.

• 신재생에너지
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• 제4권3호
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• pp.23-35
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• 2008

In the present study, performances of fuel cell driven compound source hybrid heat pump system applied to a large community building are simulated. Among several renewable energy sources, ground, river, sea, and waste water sources are chosen as available alternative energies. The performance and energy cost are varied with the hybrid heat pump sources. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a large community building. Th system is driven by fuel cell system instead of the late-night electricity due to the advantages of the low energy cost and waste heat with high temperature.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.357-362
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• 2009

As a unutilized energy, treated sewage water locates widespread near urban areas. From the previous survey, the sewage water is reported to hold energy potential up to 36,000 Tcal/year, which was 2.1% of the total domestic energy consumption and 9.7% of the energy usage in the household and business sector in 2006. Temperature of the sewage water differs locally, but its range is observed in a range of $20{\sim}25^{\circ}C$ in summer and $8{\sim}13^{\circ}C$ in winter. Since the temperature range of the sewage water has a better seasonal distribution about $5{\sim}10^{\circ}C$ compared to ambient air, it is a promising heat sink for summer or heat source for winter. The sewage water is also a high quality heat source from its abundant quantity and uniform temperature. Considering the ambient temperature of Korea is very low in winter, a heat pump system using the sewage water can be an alternative to prevent problems of capacity deficiency and frost formation.

• 한국관개배수논문집
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• 제14권2호
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• pp.181-193
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• 2007

The characteristics of non-point source pollutant loads in middle-stream of Nakdong River Were studied through analysis of pollutant loads of 8 sub-watersheds divided based on administrative district. The pollutant concentration of each sub-watershed was collected from Nakdong-River Water Research Institute and Daegu Regional Environmental Office, respectively. Pollution items analysed in this study were BOD, SS, T-N and T-P. High degree of non-point pollution was observed from Gumi, Goryeong, Gyeongsan, Daegu and Sungju, and pollution was usually increased during rainy season. This result indicates that a given pollution condition within the watershed can be more sensitive than location factor to the level of water quality. The main sources of non-point pollution were population and livestock, as well as landuse factor, and were found to significantly contribute to the water pollution. Alternative solutions for controlling pollution sources, therefore, should be provided to meet target levels of water quality in this region.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권4호
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• pp.60-70
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• 2017

As water sources become more vulnerable to the effects of climate change such as drought and contamination, the diversification of water sources is important for securing water supply. This study examines the properties of five water sources for public supply, including river and river-bed water, dams, reservoirs, and groundwater, while ensuring that the quantities available from such sources are stable and the water itself is safe for use. This study also analyzes the power, chemical, repair and maintenance, and labor costs associated with each water source. The results demonstrate that groundwater has high potential as a water source because it is readily available (about $12.89billion\;m^3/yr$), but only a small portion of it is currently used. Analyses indicated that groundwater is the most efficient source of water to meet water demand below $1,000,000m^3/yr$, which covers 62.5% of water supply facilicities. With the implementation of groundwater dams, groundwater can become cost-efficient even for larger water demand. Additionally, the water source protection areas are the smallest for groundwater among the five water sources. In conclusion, the use of groundwater as an alternative water source is feasible becasue it is readily available, safe, cost-efficient, and requires the lowest amount of environmental regulations for the diversification of water supply sources.

• 한국관개배수논문집
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• 제13권2호
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• pp.283-292
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• 2006

The characteristics of nonpoint source pollutant loads in upstream of Nakdong River were studied through analysis of pollutant loads of 10 sub-watersheds divided based on administrative district. The discharge and pollutant concentration of each sub-watershed were collected from Nakdong-River Water Research Institute and Daegu Regional Environmental office, respectively. Pollution items analysed in this study were BOD, T-N and T-P. The delivery loads of the nonpoint source pollutions of each sub-watershed were calculated after analysing the concentration of the pollution of each site. Several points were found from the results. Firstly, in general, city areas including Sangju, Andong showed higher degree of nonpoint pollution than country areas including Cheongsong, Yeongyang. The sub-watersheds located upstream side, such as Yeongju, Bonghwa, Necessarily show better water quality than the sub-watersheds located downstream side, such as Mungyeong, Uiseong. This result indicates that a given pollution condition within the watershed can be more sensitive than location factor to the level of water quality. Secondly, the delivery load and area of watershed were not necessarily correlated in the sense of water quality, while the discharge was shown to be highly correlated to the delively load of pollution. Lastly, sewage and waste caused from population and livestock, as well as landuse factor, were found to significantly contribute to the water pollution. Alternative solutions for controlling pollution source, therefore, should be provided to meet target levels of water quality in these regions.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.170-170
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• 2023

Providing safe and readily available water is vital to maintain public health. One of the most prevalent methods to prevent the spread of waterborne diseases is applying chlorine injection to the treated water before distribution. During the water transmission and distribution, the chlorine will experience a reduction, which can imply potential risks for human health if it falls below the minimum threshold. The ability to determine the appropriate initial intensity of chlorine at the source would be significant to prevent such problems. This study proposes two methods that integrate hydraulic and water quality modeling to determine the suitable intensity of chlorine to be injected into the source water to maintain the minimum chlorine concentration (e.g., 0.2 mg/l) at each demand node. The water quality modeling employs the first-order decay to estimate the rate of chlorine reduction in the water. The first method utilizes a backtracking algorithm to trace the path of water from the demand node to the source during each time step, which helps to accurately determine the travel time through each pipe and node and facilitate the computation of time-dependent chlorine decay in the water delivery process. However, as a backtracking algorithm is computationally intensive, this study also explores an alternative approach using a water age. This approach estimates the elapsed time of water delivery from the source to the demand node and calculate the time-dependent reduction of chlorine in the water. Finally, this study compares the outcomes of two approaches and determines the suitable and effective method for calculating the chlorine intensity at the source to maintain the minimum chlorine level at demand nodes.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.634-637
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• 2008

Ground source heat pumps are clean, energy-efficient and environment-friendly systems cooling and heating. Although the initial cost of ground source heat pump system is higher than that of air source heat pump, it is now widely accepted as an economical system since the installation cost can be returned within an short period of time due to its high efficiency. In the present study, performances of ground source compound hybrid heat pump system applied to a large community building are simulated. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a large community building. If among several renewable energy sources, ground, river, sea, waste water source are chosen as available alternative energies are combined, COP of the system can be increased largely and hybrid heat pump system can reduced the fuel cost.

• 한국환경과학회지
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• 제24권10호
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• pp.1239-1251
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• 2015

Impervious areas have been expanded by urbanization and the natural structure of water circulation has been destroyed. The limits of centralized management for controlling storm water runoff in urban areas have been suggested. Low impact development (LID) technologies have been promoted as a crucial alternative, establishing a connection with city development plans to build green infrastructures in environmentally friendly cities. Thus, the improvement of water circulation and the control of nonpoint source were simulated through XP-SWMM (storm water and wastewater management model for experts) in this study. The application of multiple LID combination practices with permeable pavements, bioretention cells, and gutter filters were observed as reducing the highest runoff volume by up to 70%. The results from four different LID installation scenarios indicated that permeable paving is the most effective method for reducing storm water runoff. The rate of storm water runoff volume reduced as the rainfall duration extended. Based on the simulation results, each LID facility was designed and constructed in the target area. The LID practices in an urban area enable future studies of the analysis of the criteria, suitable capacity, and cost-efficiency, and proper management methods of various LID techniques.