• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.51-51
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• 2020

본 연구에서는 기수역에서의 GPS 전자부자를 활용한 계측 데이터와 염분측정 데이터를 비교분석하여 GPS 전자부자의 거동 특성이 담수의 실제 거동특성과 같이 일치하게 나타나는지 확인하고, GPS 전자부자에 대한 활용성을 증명하고자 하였다. 기수역에서의 담수와 해수의 분포를 확인하기 위해서는 많은 인력과 장비를 소모하며 수리량과 염분도에 대한 측정을 통해 분석을 할 수 있는데, 대표적인 수리량 측정장비인 ADCP 또는 ADV는 각종 측정 한계들이 존재한다. 따라서 이러한 기수역에서의 수체 구간별 흐름 특성이 어떻게 나타나는지 확인하기 위해서 GPS 전자부자를 활용하고자 하였으며. GPS 전자부자의 데이터와 수직방향으로 측정한 염분도 데이터와 비교하고자 하였다. 수영강 좌수영교 상류 1km지점에서 주입하였으며 간조 시와 만조 시에 유하시켜 수영강에 위치한 좌수영교와 수영교에서 각각 좌측, 중간, 우측에서 수심방향으로 측정한 염분도를 상층 중층 하층으로 평균하여 비교하였다. 본 연구에서 사용한 GPS 전자부자는 표면부자이기 때문에 만조 시 하류방향으로 더 뻗어 나가는것으로 확인하였고, 간조 시에는 흐름이 더디거나 정체하는 것으로 나타났다. 이러한 계측 결과는 담수의 흐름 특성과 일치하게 나타나는 것을 확인하였고 이러한 GPS Floater를 활용한다면 굳이 각종 수질을 측정하지 않아도 흐름 상황으로 간조인지 만조인지에 대한 상황과 염분 분포를 대략적으로 알 수 있다. 이러한 GPS 전자부자의 위치데이터와 시간을 잘 이용한다면 ADCP의 유속 측정에 대한 단점을 보완할 수 있는 Lagrangian 타입의 유속을 측정 할 수 있다. 이러한 GPS 전자부자를 하천에서 선주입으로 활용한다면 각 구간별로 수체에 대한 흐름과 유속들을 분석할 수 있을 것으로 사료된다. 또한 GPS 전자부자를 좀더 활용하여 IoT 기반 수질센서 등과 같은 각종 센서가 GPS Floater에 결합이 된다면, 흘러가면서 각종 데이터 정보취득을 통해 수체내 흐름을 분석하는 것뿐만 아니라 수환경 유출오염사고들에 대한 초기대응에 많은 도움이 될 것으로 사료 된다.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.8
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• pp.591-597
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• 2011

The purpose of this study was to determine optimum conditions for the cultivation of Chlorella sp. FC-21 using light emitting diodes (LEDs). Specific growth rate and cell concentration were measured for the reactors at the illuminations of different wavelengths of LEDs. Among various types of LEDs, red LEDs were the most effective light source, and also greatest increases of specific growth rate and cell concentrations were obtained when light intensity of red LEDs increased. The specific growth rate decreased when initial cell concentration increased due to the shading effect of each cell in the reactor. To determine beneficial effect of aeration to cell cultivation, micro-air bubbles were aerated at 0.35 vvm in the reactor at the illumination of red LEDs. Two and ten times greater specific growth rate and cell concentration were obtained when aeration was applied. From this study, we found that red LEDs with aeration were the most appropriate light source for the cultivation of Chlorella sp. FC-21.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.113-119
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• 2006

Recently, the ground injection method using water glasses as one of the main resources and the products of these constructions have basic problems in terms of the method of constructions for the permanent foundation reinforcement and stopping leakage of water because they have some serious problems such as durability, compressive strength, injectant eluviation and so forth even though they are still used to stop leakage of water in the temporary structures. The purpose of this study is to demonstrate the strength characteristic and environment friendliness of NDS method by unconfined compressive strenth test, permeability test, length change test, leaching test, and assessment of environmental impact in comparison water glass type material. The test results show that NDS method has significant improvement of strength, permeability, volume change, and leaching. An assessment of environmental impact also demonstrates that the NDS material is environmentally friendly.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.1
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• pp.62-69
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• 2000

The study was performed to apply the algae removal system to coagulation-filtration process for minimize the damage to screen interruption of water treatment plants and died of fish by algae bloom on freshwater. Sample used Nokdong river water and Alkalinity, turbidity, chlorophyll-a and pH measured using Jar test and drum filter for coagulation-filtration process to determine optimum coagulation condition. A jar test apparatus and laboratory reactor were used in this study. The highest removal efficiency was observed when condition of flocculation time, coagulant dosage, drum filter rpm and chlorophyll-a concentration were to be 5min, 5mg/ℓ, 3rpm and 90㎍/ℓ, respectively. The average removal efficiencies measured of chlorophyll-a and turbidity using Alum were 50～60% and 30～50%, respectively. PAC was more effective than Alum in removal chlorophyll-a about 20%.

• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.21-33
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• 2013

The purpose of the study is to evaluate engineering properties of Ferro Nickel Slag (FNS) and to investigate the effects of FNS on potential contamination of surrounding soil and water through small and large chamber tests. Soil conditions in the chamber tests were made as closely as possibile to the field conditions. In order to simulate different types of water, we used fresh water, acidic water and seawater. Sand soils were made with relative densities of 40% and 60%, and clay with the degree of compaction of 90%. After flushing water through the FNS in the chambers was completed, the PH test was performed for the water flowing out of the chambers and the soil samples were collected for soil pollution analysis. Based on the results of the chamber tests, although the pollution level was slightly higher in the silt than in the sand, the environmental effect that FNS causes the surrounding soil was found to be very minimal. This indicates that FNS can be used as construction material in place of natural aggregates.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.8-8
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• 2019

전 세계적으로 ASR, ASTR과 같은 인공함양에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 수자원을 확보하고 생산수의 수질 개선을 꾀할 수 있는 지하 저수지 기술을 개발하고 낙동강 하구의 염 대수층에 설치한 시험시설에서 검증하였다. 국내외 대 하천의 하구에는 상부에는 점토층이 발달해 있고 하부에는 대수층이 대규모로 발달해 있으나 염 지하수로 포화되어 있는 경우가 많다. 점토층은 오염된 지표수나 지표면에서 발생한 오염사고로부터 하부의 피압 대수층을 분리하는 역할을 할 수 있다. 따라서 피압 대수층은 기존의 지표수 수자원 또는 대체 수자원의 한계를 극복할 수 있는 좋은 수자원 확보 공간이 될 수 있다. 지하 저수지 실증 연구를 위하여 낙동강 하구의 피압 대수층에 주입정, 양수정과 관측정 등을 포함한 시험 시설을 설치하였다. 낙동강에서 취수한 지표수의 부유물을 제거하고 대수층에 주입하여 기존의 염 지하수를 밀어내고 렌즈 형태의 담수체 (지하 저수지)를 조성하였다. 양수정과 관측정을 통하여 조사된 지하 저수지는 원 지하수가 배제되었고, 하천수보다 수질이 개선되었음을 보였다. 본 고에서는 실증 연구에서 도출된 수자원 확보 및 수질 개선 성과를 제시하고자 한다. 지하 저수지는 공사 규모가 작고, 수몰지가 발생하지 않으며, 수요지 인근에 위치해 있어 지역 내 수자원 자급이 가능하고, 토지 이용도 자유롭다. 또한 평상 시에 연중 균일한 양질의 수자원 공급이 가능하고 가뭄, 지표수 오염 등 비상 시에도 장기간 안정적으로 청정 수자원 공급이 가능하다. 지하 저수지는 물 안보도 제고를 위한 취수원 다변화 차원에서 기여할 수 있을 것으로 판단된다.

• Geophysics and Geophysical Exploration
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• v.18 no.3
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• pp.143-153
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• 2015

Polymer flooding for enhancing hydrocarbon production injects into a reservoir polymer solution that is viscous. It is very important to monitor the behavior pattern of the polymer solution in order to evaluate the effectiveness of polymer flooding. To monitor the distribution of polymer solution and thus fluid substitution within the reservoir, we first construct seismic and resistivity rock physics models (RPMs), which are functions of reservoir parameters such as rocks and type of fluid, fluid saturation. For the seismic and resistivity RPMs, responses of seismic and electromagnetic (EM) tomography are numerically simulated as polymer injection, using two dimensional (2D) staggered-grid finite difference elastic modeling and 2.5D finite element EM modeling algorithms, respectively. In constructing RPM for EM tomography, three different reservoir rocks are considered: clean-sand, dispersed shale-sand, and sand-shale lamination rocks. The polymer solution is assumed to have 2 wt% of polymer as normally generated, while water is freshwater or saltwater. Further, neutron logging is also considered to check its sensitivity to polymer flooding. The techniques discussed in the paper are important in monitoring not only hydrocarbon but also geothermal reservoirs.

• Parasites, Hosts and Diseases
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• v.29 no.2
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• pp.129-138
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• 1991

Tetrahymena pyriformis is a free-living ciliate protozoan in the freshwater system. Experiments were carried out to determine whether intraperitoneal administration of T. pyriformis (GL strain) to mice activates macrophages to be able to kill Toxoplasma gondii tachyzoites in vitro. Mice were also injected intraperitoneally with several synthetic activators; dimethyldioctadecylammonium bromide (DDA), dextran sulfate, complete Freund's adjutant (CFA) as well as Toxoplasma and Tetrehymena Iysates in order to activate mouse peritoneal macrophages. One week after the administration of activators, peritoneal cells were harvested and the adherent macrophages were challenged with Toxoplasma tachyzoites. Macrophage monolayers were then fixed with absolute methanol after washing, and stained with Giemsa solution. The percentage of the adherent cells infected and total number of organisms per 100 macrophages were calculated to make toxoplasma-cidal activity of macrophages according to the cultivation time. Peritoneal macrophages from mice administered with Tetrahymena exhibited significant protection against target parasites as compared with those treated with synthetic activators. Among non-biological synthetic activators, DDA was evaluated as an ellcellent activator.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.8
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• pp.554-560
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• 2014

To investigate the applicability of montmorillonite to capping material for the remediation of contaminated marine sediment, adsorption characteristics of $PO{_4}{^{3-}}$ onto montmorillonite were studied in a batch system with respect to changes in contact time, initial concentration, pH, adsorbent dose amount, competing anions, adsorbent mixture, and seawater. Sorption equilibrium reached in 1 h at 50 mg/L but 3 h was required to reach sorption equilibrium at 300 mg/L. Freundlich model was more suitable to describe equilibrium sorption data than Langmuir model. The $PO{_4}{^{3-}}$ adsorption decreased as pH increased, due to the $PO{_4}{^{3-}}$ competition for favorable adsorption site with OH- at higher pH. The presence of anions such as nitrate, sulfate, and bicarbonate had no significant effect on the $PO{_4}{^{3-}}$ adsorption onto the montmorillonite. The use of the montmorillonite alone was more effective for the removal of the $PO{_4}{^{3-}}$ than mixing the montmorillonite with red mud and steel slag. The $PO{_4}{^{3-}}$ adsorption capacity of the montmorillonite was higher in seawater than deionized water, resulting from the presence of calcium ion in seawater. The water tank elution experiments showed that montmorillonite capping blocked well the elution of $PO{_4}{^{3-}}$, which was not measured up to 14 days. It was concluded that the montmirillonite has a potential capping material for the removal of the $PO{_4}{^{3-}}$ from the aqueous solutions.

• Korean Chemical Engineering Research
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• v.44 no.1
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• pp.46-51
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• 2006

As one of the $CO_2$ reduction strategies, a biological method was proposed to convert $CO_2$ to useful biomass with antioxidant carotenoids by photosynthetic microorganisms. One of the photoautotrophs, Haematococcus pluvialis is a freshwater green microalga and accumulates the secondary carotenoid astaxanthin during induction of green vegetative cells to red cyst cells. In this study, $CO_2$ fixation and astaxanthin production using H. pluvialis was conducted by photoautotrophic culture in the $CO_2$ supplemented photo-incubator. Maximum growth rate of H. pluvialis was obtained at a 5％ $CO_2$ environment on basic N and P conditions of NIES-C medium. The photoautotrophic induction consisted of 5％ $CO_2$ supply and high light illumination promoted astaxanthin synthesis in H. pluvialis, yielding an astaxanthin productivity of $9.6mg/L{\cdot}day$ and a $CO_2$ conversion rate of $27.8mg/L{\cdot}day$ to astaxanthin. From the results the sequential photoautotrophic culture and induction process using H. pluvialis is expecting an alternative $CO_2$ reduction technology with a function of valuable biosubstance production.