• Environmental Engineering Research
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• 제21권4호
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• pp.319-332
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• 2016

Micropollutants are often discharged to surface waters through untreated wastewater from sewage treatment plants and wastewater treatment plants. The presence of micropollutants in surface waters is a serious concern because surface water is usually provided to water treatment plants (WTP) to produce drinking water. Many micropollutants can withstand conventional WTP systems and stay in tap water. In particular, pharmaceuticals and endocrine disruptors are examples of micropollutants that are detected at the drinking water, ppb, or even ppb level. A variety of techniques and processes, especially advanced oxidation processes, have been applied to remove micropollutants from water to control drinking water contamination. This paper reviews recent researches on the occurrence and removal of micropollutants in the aquatic environments and during water treatment processes.

• Journal of the Korean Wood Science and Technology
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• 제32권3호
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• pp.1-7
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• 2004

The application of abrasive-assisted high energy water-jet was investigated as a possible new method of cutting wood. In this study the maximum cutting speeds for species of various wood density were determined and water-jet machining characteristics were investigated for sixteen Korean domestic species. The maximum cutting speed ranged from 200 to 750 mm/min. The results indicate that wood density affects machining characteristics such as maximum cutting speed, surface roughness, and kerf width. Roughness of surface generated increased and kerf width decreased as penetration depth increased.

• 지질공학
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• 제21권1호
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• pp.45-55
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• 2011

본 연구에서는 소하천변 충적층을 대상으로 9개 지하수 관측공내 유속 실험과 온도 계측을 통한 시간별, 심도별 온도 변화 추이 평가 및 지화학 분석 등을 통하여 지표수와 지하수간의 상호 작용에 대하여 분석하였다. 하천변에 근접한 2개 지하수 관측공은 타 관측공과 달려 지하수 유향이 하천에서 주변 충적층으로 향하고 있으며, 계절에 따른 온도 변화가 대기 및 하천과 유사하게 나타난다. 또한 이들 지점은 하천수의 영향을 받은 지화학 특성을 보일 뿐 아니라 계절에 따라 지화학 특성이 변화하는 등 지표수의 유입 유출이 활발한 지점에 해당한다. 본 연구에서 사용된 온도 측정 장치인 Thermochron I-button은 저비용의 소규모 장치로서 지표수와 지하수의 상호 작용 평가에 활용도가 높다.

• 한국해양학회지
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• 제11권2호
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• pp.89-95
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• 1976

우리 나라 연안에 대한 해양학적 조사는 그렇게 조직적으로 조사된 편이 못된다. 1960년대 이후로 수질오염과 관련해서 연안수질조사를 많이 실시해왔지만(원;1963, 1964, 1970, 장과 배;1968, 박 등;1969, 이 등;1969, 김;1970, 원과 박;1970, 1973, 최와 정;1971, 1972, 강;1972, 이 등;1972a, b, 1973, 1974a, b, c, d, e, 1975a, b, 변 등;1973, 한 등;1973, 황 등;1973, 1974, 1975, 김과 조;1974a, b, 박 등;1974a, b 박과 조;1974, 이 등;1974, 정과 권;1974, 곽과 이;1975, 박 등;1975, 박;1975a, b, 김 등;1976, 김 등;1976, 김과 김;1976) 대부분이 해양의 특성을 파악하는데 불충분했고 단 한번을 조사하더라도 면밀한 조사를 실시한 예는 그리 많지 못하다.

• 한국도로학회논문집
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• 제8권2호
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• pp.13-22
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• 2006

Surface fog coating methods to porous pavements with a polymer, that contains MMA as a main ingredient, are being widely used in Japan and called 'Top-Coat Processes'. They have lots of effects such as to prevention of the pavement void choking, improvement of the water permeability of the pavements and so on. The purpose of this research is to show the characterization of the polymer to optimize the functions of the polymer fog-coat methods. This study focused on the difference of 'wetting' by water among polymers used for the fog coatings, and calculation the surface free energy from the water contact angle on each material. At the end, the water permeability test were conducted using porous asphalt mixtures that were coated with several kinds of polymers. The permeability was also measured on the specimens that were forcibly choked by muddy water and the resistance to choking was compared. It is concluded that the reduction of the surface free energy between water and a polymer improves the life of the permeability functions of porous pavements. Improvement of water permeation capacity and void-blocking controlling effects can be quantitatively evaluated using the interfacial tension ($\gamma$sl) with water for the coating material (high-viscosity asphalt and hardening resin binder). Consequently, the smaller the $\gamma$sl of the coating material the higher the water permeation capacity and void-blocking controlling effects of the porous asphalt pavements.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.272-273
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• 2013

Some living thingsuse micro- or nano- structures for living in nature. Scientists and engineers made efforts to mimic them, and they succeeded in making new types of applications. They used 'Namib desert beetle' to self-filling device by moisture harvesting and 'lotus leaf' to self-cleaning device by water repelling. 'Namib desert beetle' and lotus leaf have micro-patterns on their surface, which consists of hydrophobic or hydrophilic materials [1]. Moreover, micro-patterns on the surface make self-filling or self-cleaning property enhanced because of the surface roughness. Surface roughness enhances wettability [2]. Micro-pattern is a significant factor to make the surface be functional, so we want to make new types of functional surface by micro-patterning. In this work,we make several functional micro-patterns (radial, line, and dot arrays) using maskless lithography and analyze the characteristics of each micro-pattern. In order to analyze and understand surface characteristics, micro-patterns with varying sizes are investigated. All experiments are proceeded on mr-DWL5 photo resists coated on silicon wafers in same condition. All the experiments have demonstrated good performances about hydrophobic or hydrophilic property corresponding to their material and structural combinations. In radial micro-pattern, although the surface is flat, water drops on hydrophilic radial pattern can be convergent to a middle point and water drops on hydrophobic radial pattern can be divergent from the middle point. In line array micro-pattern, water drops can roll off along only one direction in parallel with the line arrays. Such phenomena might be mainly caused by the local change of surface roughness. From these results, controlling the movement and direction of water drops is made feasible without introducing a slope, which can potentially be used for new types of applications.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.389-394
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• 2008

The purpose of this research was to develop a methodology to determine whether conjunctive surface water and groundwater management could significantly reduce deficits in a river basin with a relatively limited alluvial aquifer. The Geum River basin is one of major river basins in South Korea. The upper region of the Geum River basin is typical of many river basins in Korea where the shape of river basin is narrow with small alluvial aquifer depths from 10m to 20m and where most of the groundwater pumped comes quickly from the steamflow. The basin has two surface reservoirs, Daecheong and Yongdam. The most recent reservoir, Yongdam, provides water to a trans-basin diversion, and therefore reduces the water resources available in the Geum River basin. After the completion of Yongdam reservoir, the reduced water supply in the Geum basin resulted in increasing conflicts between downstream water needs and required instream flows, particularly during the low flow season. Historically, the operation of groundwater pumping has had limited control and is administered separately from surface water diversions. Given the limited size of the alluvial aquifer, it is apparent that groundwater pumping is essentially taking its water from the stream. Therefore, the operation of the surface water withdrawals and groundwater pumping must be considered together. The major component of the conjunction water management in this study is a goal-programmin g based optimization model that simultaneously considers surface water withdrawals, groundwater pumping and instream flow requirements. A 10-day time step is used in the model. The interactions between groundwater pumping and the stream are handled through the use of response and lag coefficients. The impacts of pumping on streamflow are considered for multiple time periods. The model is formulated as a linear goal-programming problem that is solved with the commercial LINGO optimization software package.

• 자원환경지질
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• 제30권1호
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• pp.25-33
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• 1997

The purpose of this study is to examine the feasibility of using stable isotopes as a hydrologic tracer, and to elucidate the groundwater circulation system and the source of S component dissolved in thermal water of the Chonju Jukrim thermal spring district based on the O, H and S isotopic variabilities of environmental materials including bedrock, rainwater, surface water, shallow subsurface water and thermal spring water. The ${\delta}^{18}O$ and ${\delta}D$ of subsurface waters and surface water show highly restricted range and plotted on the same meteoric water line as a ${\delta}D=8{\delta}^{18}O+19$ line, and derivate from the mean annual isotopic composition of the rain water but are analogous to those of rain waters precipitated during winter season, indicating that ground waters are originated from the meteoric water and are strongly affected by the seasonal variation of air mass. Thermal spring waters are more depleted in ${\delta}^{18}O$ and ${\delta}D$ than those of shallow ground water and surface water. It can be explained by the difference of recharge area. The hydrochemical properties of subsurface waters and surface water devide into two groups: $Ca(HCO_3)_2$ type including shallow subsurface water and surface water, and $Na(HCO_3)$ type of thermal spring waters. The ${\delta}^{34}S$ values of thermal spring water show very high positive and quitely distinct from those of shallow subsurface water and surface water that are similar to those of bed rocks, indicating that sulfate dissolved in thermal spring water has not only a terrigenic origin, but also originates partially from the foreign source containing very heavy ${\delta}^{34}S$ component such as an ancient sea water. However, the presence of $H_2S$ can not be ignore the affact of the isotopic fractionation to explaine the heavy ${\delta}^{34}S$ of thermal spring water. Overall, the Oxygen and Hydrogen stable isotopes can identify the source and the circulation system of the natural waters and the S-isotopes can provide a crucial clue on tracing the dissolved material transports in the circulation system of the natural water.

• 한국농공학회논문집
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• 제62권6호
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• pp.1-9
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• 2020

Reservoir storage and water level information is essential for accurate drought monitoring and prediction. In particular, the agricultural drought has increased the risk of agricultural water shortages due to regional bias in reservoirs and water supply facilities, which are major water supply facilities for agricultural water. Therefore, it is important to evaluate the available water capacity of the reservoir, and it is necessary to determine the water surface area and water capacity. Remote sensing provides images of temporal water storage and level variations, and a combination of both measurement techniques can indicate a change in water volume. In areas of ungauged water volume, satellite remote sensing image acts as a powerful tool to measure changes in surface water level. The purpose of this study is to estimate of reservoir storage and level variations using satellite remote sensing image combined with hydrological statistical data and the Normalized Difference Water Index (NDWI). Water surface areas were estimated using the Sentinel-2 satellite images in Seosan, Chungcheongnam-do from 2016 to 2018. The remote sensing-based reservoir storage estimation algorithm from this study is general and transferable to applications for lakes and reservoirs. The data set can be used for improving the representation of water resources management for incorporating lakes into weather forecasting models and climate models, and hydrologic processes.

• 생태와환경
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• 제38권1호통권110호
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• pp.118-127
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• 2005

관개방법이 논에서의 수문 및 수질특성에 미치는 영향을 파악하기 위하여 관개용수가 풍부한 지표수 관개지역과 관개용수가 부족한 지하수관개지역에서의 물수지 및 영양물질수지 분석을 실시하였다. 지표수 관개논은 영농 기간동안 지속적으로 관개가 이루어졌으나, 지하수 관개논은 영농초기에만 이루어졌으며, 그 이후에는 강우에 의해 담수심이 유지되어 지표유출은 지표수 관개논에 비해 상대적으로 낮은 빈도를 나타내었다. 지표수의 영양물질 농도는 시비에 의해 크게 영향을 받는 것으로 나타났으며, 특히 다량의 시비가 이루어지는 영농초기 (5 ${\sim}$ 6월 중순)에는 높은 영양물질 농도를 나타내어 이 시기에 논에서 유출이 이루어진다면 하류 수계에 영향을 줄 것으로 판단되었다. 물수지 분석결과 지하수 관개논의 관개량, 지표유출량 등이 상대적으로 지표수 관개논에 비해 낮은 값을 나타내었다. 영양물질수지분석 결과 대부분의 유입은 시비에 의해 이루어졌으며, 유출은 지표유출이 많은 비중을 차지하였으나 지표유출과 침투유출사이의 비율은 토양의 특성에 좌우되는 것으로 판단된다. 외부에서의 유입을 제외하고 시스템내에서의 유출입만 고려한다면, 물관리가 효율적으로 이루어진 지하수 관개논에서 낮은 부하량을 나타내었다. 그러나 기비가 이루어지고 인위적인 낙수나 강우에 의한 유출이 발생할 경우, 높은 부하량 뿐만 아니라 고농도의 영양물질질이 수계로 유입되는 것으로 나타났다. 논에서의 비점오염관리를 대안으로 현재 시행되고 있는 시비량 감소 뿐 아니라, 효율적인 물관리기법 개발이 포함되어야 할 것으로 판단된다. 특히 영농초기의 강우특성과 논에서의 담수기능을 고려해 볼 때 시비에 의한 높은 영양물질 농도를 나타내는 논 표면수의 유출을 효율적으로 억제할 수 있을 것으로 판단된다. 물꼬높이의 증가와 천수간단관개 영농초기의 강우에 의한 유출을 억제시킴으로써 부족한 관개용수의 절약 뿐만 아니라 하류수계의 수질보호에 기여를 할 것으로 판단되며, 다양한 조건에 따른 환경적인 측면 뿐 아니라 벼의 생리적인 측면은 장기적인 모니터링을 통해 반드시 고려되어야 할 것이다.