• 한국습지학회지
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• 제13권3호
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• pp.633-641
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• 2011

필리핀의 연평균강수량은 약 965mm ~ 4,100mm로 수자원이 비교적 풍부하다. 필리핀의 최근 급증하는 도시화로 인해, 필리핀의 마닐라 지역에서는 용수의 수요량이 매년 증가하는 추세이다. 용수의 부족을 해소시키기 위해 필리핀의 풍부한 수자원을 적절하게 사용하여야 하며, 이를 위한 방법 중의 하나로 강우의 유출수를 이용하는 우수저류시설이 가용하다고 판단된다. 따라서 본 연구에서는 마닐라 주거지역에서의 우수저류시설에 대한 잠재가용성을 분석하였으며, 그 방법으로는 일별강우, 유역면적, 유출계수, 인구밀도 그리고 용수수요량 등을 매개변수로 사용하는 물수지방정식을 이용하였다. 세 가지 강우조건(연평균 강우중 최소, 중간, 최대값)과 세 가지 화장실종류(저효율식, 재래식, 절수식)에 따른 가정용수탱크 사용에 대하여 분석하였다. 그리고 대상지역에서의 최적의 강우 저장 면적을 결정하기 위해 월류용적을 사용하였다. 연구결과 세 가지 강우조건에서, 재래식과 절수식 화장실이 우수저류시설에 가장 부합되며, $60m^3$저류용량의 탱크는 3개월간 90가구의 용수수요를 충분히 공급 가능 하다고 나타났다. 본 연구를 통해 주거지역의 장기간 용수수요를 충족시키기 위해서는 저류탱크 용량은 $1,100m^3{\sim}2,500m^3$이 적당하다고 판단된다.

• 상하수도학회지
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• 제26권2호
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• pp.191-199
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• 2012

Rainwater harvesting systems (RWHS), one of measures for on site rainwater management, have been promoted by laws, regulations and guidelines and have been increased. However, more evaluation of economic feasibility on RWHS is still needed due to seasonal imbalance of rainfall and little experiences and analysis on design and operation of RWHS. In this study, we investigated tank capacity of RWHS to secure economic validity considering catchment area and water demand, which is affected by building scale. Moreover, sensitivity analysis was performed to examine the effect of design factors, cost items and increase rate of water service charge on economic feasibility. The BCR (benefit cost ratio) is proportional to the increase in tank capacity. It is increased steeply in small tank capacity due to the effect of cost and, since then, gently in middle and large tank capacity. In case of 0.05 in the rate of tank volume to catchment area and 0.005 in water demand to catchment area, BCR was over one from the tank capacity of 160 $m^{3}$ taking into account of private benefits and from the tank capacity of 100 $m^{3}$ taking into account of private and public benefits. Sensitivity analysis shows that increase of water demand can improve BCR values with little cost so that it is needed to extend application of rainwater use and select a proper range of design factor. Decrease of construction and maintenance cost reduced the tank volume to secure economic validity. Finally, increase rate of water service charge had considerable impact on economic feasibility.

• 한국물환경학회지
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• 제28권2호
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• pp.269-276
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• 2012

The surface characteristics and performance of PTFE (polytetrafluoroethylene) hollow fiber membranes have been systematically investigated at lab- and pilot-scale to assess their application to membrane-bioreactor, particularly for integrating wastewater reclamation and rainwater harvesting. The PTFE membrane expressed some surface features, such as hydrophobicity, which might enhance membrane fouling. However, lab-scale performance and cleaning experiments under various conditions demonstrated that the PTFE membrane could produce the desirable water flux with good cleaning efficiency, implying easy operation and maintenance due to superior chemical resistance of PTFE membranes. Most of effluent water qualities were met with Korean standard for discharge and reuse, except color. Color level was further reduced by blending with rainwater at 75:25 ratio. Based on the lab-scale experimental results, the pilot plant was designed and operated. Pilot operation clearly showed sTable performance with satisfactory water quality, suggesting that PTFE membrane could be applied for decentralized MBR integrated with rainwater use.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.386-389
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• 2013

Under climate change and urbanization, rainwater harvesting (RWH) systems are emerging as an alternative source of water supply because of growing concern about water sustainability. RWH systems can satisfy the various watering needs and provide the environmental benefits of lessening the damages from flood, drought, and runoff. The economic success of a RWH system is vitally concerned with the determination of the design capacity of storage tank to be built in the system. The design capacity is determined by the factors of average annual rainfall, period of water scarcity, and water price during the whole life-cycles. Despite the high uncertainties inherent in these factors, the current engineering design of RWH system construction often assumes that storage tanks should be built all at once. This assumption implicitly ignores the managerial flexibility in responds to the future as new information comes out-the right to build storage tanks stage by stage depending on the evolution of demand. This study evaluates the value of a multistage storage tank construction using a real option approach. A case study involving a typical RWH system construction in Jeonju, the Republic of Korea is conducted. The managerial flexibility obtained from the real option perspective allows engineers to develop investment strategies to better cope with the issue of water sustainability.

• Environmental Engineering Research
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• 제18권2호
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• pp.103-108
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• 2013

Vietnam is a developing country with the rate around 5%-6% per year, especially in urban areas. Rapidly developed urban areas lead to stress for infrastructure and the water supply is also stressed. In Hanoi city, total water capacity from the manufactories is around one million cubic meters per day and almost the entire main water source is groundwater but it is not enough to supply all of Hanoi's people, especially in the summer. A demo project is implemented in Hanoi University of Civil Engineering (HUCE) to produce drinking water by using the rainwater and membrane system and supply for people. In this project, rainwater is collected on the rooftop of the lecture building with an area of around $500m^2$ and $100m^3$ volumetric rainwater tanks. Afterwards, the rainwater is treated by the micro-membrane system and supplied to the tap water. Total cost for construction, technology and operation in the first year is around USD 48,558. In the long-term (15 yr) if HUCE invests in the same system, with $20m^3$ volumetric storage tank, it can provide drinking water for 500 staffs in every year. The cost of investment and operation for this system is lower than 30% compared to buying bottled water with the price USD 1.8/bottle. The drinking water parameters after treatment are pH, 7.3-7.75; turbidity, 0.6-0.8 NUT; total dissolved solids, 60-89 mg/L; coliform, 0; heavy metal similar with water quality in the bottle water in Vietnam.

• 한국수자원학회논문집
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• 제53권9호
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• pp.681-690
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• 2020

일반적으로 빗물이용시설의 설계 저류 용량은 다양한 시나리오(저류 용량, 공급 보장률, 우수 이용률 등)에 대한 반복적인 계산을 통해 결정된다. 이 방법은 분석에 많은 시간이 소요될 뿐만 아니라 많은 계산이 수반되므로 분석 오류가 나타날 수도 있다. 본 연구에서는 이러한 문제점을 해결하기 위해 최적화 기법을 이용하여 임의의 목표 보장률을 만족하는 최소의 저류 용량을 직접적으로 결정할 수 있는 방법을 제시하였다. 해당 방법은 Python 언어를 이용하여 모의 모형과 입자 군집 최적화를 연계하여 구현되었다. 최적화 기법은 Python의 오픈 소스로 제공되는 pyswarm을 이용하였는데, 해당 알고리즘은 전역 최적해 탐색이 가능하고, 제약조건을 고려할 수 있다. 최적화 기법을 이용한 빗물이용시설의 저류 용량 결정 방법은 인천 청라지구 1공구에 설치된 빗물이용시설의 설계자료에 적용하여 분석의 효율성, 안정성, 정확성을 검증하였다. 본 연구에서 제시한 빗물이용시설의 저류 용량 결정 방법은 현재의 분석 기술 수준을 개선할 수 있으므로 실용적 가치가 있는 것으로 판단된다.

• 한국물환경학회지
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• 제26권5호
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• pp.740-746
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• 2010

Rainwater has been used in many countries as a way of minimizing water availability problems. Rainwater harvesting system (RHS) has been successfully implemented as alternative water supply sources even in Korea. Although RHS is an effective alternative to water supply, its efficiency is often heavily influenced by temporal distribution of rainfall. Since natural precipitation is a random process and has probabilistic characteristics, it will be more appropriate to describe these probabilistic features of rainfall and its relationship with design storage capacity as well as supply deficit of RHS. This study presents the methodology to establish the relationships between storage capacities and deficit rates using probability distributions. In this study, the real three-story building was considered and nine scenaries were developed because the daily water usage pattern of the study one was not identified. GEV, Gumbel and the generalized logistic distribution ware selected according to the results of Kolmogorov-Smirnov test and Chi-Squared test. As a result, a set of curves describing the relationships under different exceedance probabilities were generated as references to RHS storage design. In case of the study building, the deficit rate becomes larger as return period increases and will not increase any more if the storage capacity becomes the appropriate quantity. The uncertainties between design storage and the deficit can be more understood through this study on the probabilistic relationships between storage capacities and deficit rates.

• 상하수도학회지
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• 제18권2호
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• pp.99-109
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• 2004

• 한국물환경학회지
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• 제27권5호
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• pp.634-645
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• 2011

A newly developed rainwater harvesting (RWH) system reliability model is evaluated for roof area of buildings in Haeundae District of Busan. RWH system is used to supply water for toilet flushing, back garden irrigation, and air cooling. This model is portable because it is based on a non-parametric precipitation generation algorithm using a markov chain. Precipitation occurrence is simulated using transition probabilities derived for each day of the year based on the historical probability of wet and dry day state changes. Precipitation amounts are selected from a matrix of historical values within a moving 30 day window that is centered on the target day. Then, the reliability of RWH system is determined for catchment area and tank volume ranges using synthetic precipitation data. As a result, the synthetic rainfall data well reproduced the characteristics of precipitation in Busan. Also the reliabilities of RWH system for each of demands were computed to high values. Furthermore, for study area using the RWH system, reduction efficiencies for rooftop runoff inputs to the sewer system and potable water demand are evaluated for 23%, 53%, respectively.

• 멤브레인
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• 제24권1호
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• pp.31-38
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• 2014

지붕이나 여러 가지 방법과 장소에서 수집된 빗물을 처리하면 직접적 간접적으로 유익하게 사용될 수 있다. 이러한 빗물은 점점 더 높은 품질을 위해 고려되고 있고, 분리막은 이러한 빗물 처리를 위한 중요한 기술이다. 특히, 분리막은 고품질 물 생산, 높은 집적도 및 낮은 에너지 소비 등의 장점이 있다. 그럼에도 불구하고, 막오염은 수처리 및 폐수 재활용 부분과 마찬가지로 심각한 문제로 간주되고 있다. 본 연구에서는 빗물 처리에 정밀여과(MF)막을 적용하였고, 저압 자외선(LPUV) 처리를 정밀여과막의 전처리로 사용하였다. 유기물에 대한 UV의 영향을 정량화하기 위해 총 유기탄소(TOC) 및 UV 흡광도(UVA)를 모두 측정하였다. 또한 UV 전처리 효과에 따른 막의 오염 정도를 조사하였다. LPUV 전처리를 하고 실험을 한 결과 조류에 의해 오염된 빗물에서 막의 오염을 제어하는데 효과적임을 알 수 있었으며, 이것은 UV 처리 후 유기물의 양이 감소하고 특성이 변화하기 때문이었다. 따라서 UV/MF 처리는 마이크로 워터 그리드 시스템과 같은 수처리를 위한 유망한 옵션이 될 수 있을 것으로 생각된다.