• Journal of Korean Society of Environmental Engineers
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• v.34 no.2
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• pp.73-78
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• 2012

In this study, three different synthetic musk compounds (SMCs) in the Nakdong river water (raw water) and rapid sand filtered water were treated by $O_3$ process. The experimental results showed that the removal efficiency of musk ketone (MK) was lower than removal efficiency of AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene) and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[c]-2-benzopyran) for both the raw water and the rapid sand filtered water. And in general, the removal efficiencies of three SMCs in the raw water were lower than that in the sand filtered water. Under the $O_3$ dose of 0.5~10.0 mg/L, the removal rate constants (k) of three SMCs for the raw and sand filtered waters increased rapidly with the increased $O_3$ dose. In the case of drinking water treatment plants (DWTPs) which were selected pre- and post-$O_3$ processes (located in the downstream of Nakdong River), operation conditions of pre- and post-$O_3$ process were $0.5{\sim}2.0mg{\cdot}O_3/L$ (2~4 min) and $0.5{\sim}2.5mg{\cdot}O_3/L$ (6~8 min). Therefore, $O_3$ doses and contact times of same conditions with above were very difficult to remove SMCs in DWTPs.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.86-93
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• 2021

In order to remove particulate matter, functional construction materials are developed. However, there is no evaluation method and infrastructure for particulate matter removal rate. Therefore, the purpose of this study was to build a particulate matter removal rate test chamber and to present a method for particulate matter removal rate. As a result, since construction materials have effectiveness in an environment where particulate matter is generated, the particulate matter injection step was proposed as a comparison target. The evaluation of the particulate removal rate was proposed by relative comparison of the slope values obtained by linear regression analysis for all concentration values measured in the particulate matter injection step. In linear regression method, all measured values can be evaluated, and the variability can be evaluated with the coefficient of determination (R-square), so that the reliability of the particulate matter removal rate can be secured.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.385-394
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• 1994

Numerical solutions were obtained to the model equations for various of the parameters characterizing the pore structure, effective internal diffusion, and the chemical reaction constant. The conversion was decreased with the cause of pore closure at the surface of reacting particles, reduction of porosity, surface area of reaction and effective diffusion coefficient in the solid with the progress of reaction. Total conversion was strongly dependent on the local conversion at surface. According to the decreasing of impregnated concentration of the copper oxide and the increase of the flue gases concentration, total conversion was increased. The conversion was affected by gas flow rate and pore size distribution in the reacting solid.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.3
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• pp.1-9
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• 1984

A mult-stage rotating biological contactor process was evaluated by using the mixtures of nightsoil and sewage as influent substrate. An emphasis was concentrated on the BOD removal efficiency at each stage of the process with respect to hydraulic detention times, rotating speeds of the disc and influent organic substrate concentrations. The results indicated that the process was found to be economically feasible when operated at hyduraulic detention time of 2 hours and disc rotating speed of 3 RPH. As to treatment efficiency, BOD removal efficiency of 40 to 50 percent could be obtained at the first stage regardless of influent organic substrate concentrations. The overall BOD removal efficiency of the process was found to be 88 to 90 percent at even high organic loading of $2.0kgBOD/m^3{\cdot}day$.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.192.2-193
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• 2003

기존 저온저장고의 가습방법을 개선하고 아울러 음이온을 농산물의 선도 유지에 이용하고자 아쿠아이온발생시스템의 설계, 제작이 레너드효과를 응용하여 이루어졌다. 시스템의 아쿠아음이온의 발생량은 42,965음이온/cc, 입자크기는 $10^3$$\mu\textrm{m}$ 이하, 가습속도는 0.13$\ell$/h이었으며 85% 이상의 고습도 조건에서도 결로가 발생하지 않는 상태로 가습이 가능하였다. 아쿠아이온 클러스터에 의해 저장고는 90% 이상의 균일한 고습도와 정온을 유지할 수가 있었다. 아쿠아이온시스템의 경우 유해가스와 분진등을 흡착, 제거하여 저장고 내를 청정하게 유지시키는 기능이 있는데, 에틸렌가스 제거 효과는 초기 농도 50ppm에서 5분후에 50% 이상이 제거되고 2시간 후에는 3ppm 이하로 제거되었다. 아쿠아이온발생시스템이 브로콜리, 잎상추, 애호박 등의 보관에 적용되었다. 아쿠아이온발생시스템이 부착된 저장고($0^{\circ}C$)에서 20일동안 보관한 경우 기존 저장고에 보관한 경우에 비하여 감모율, 부패율 및 관능적 품질에 있어서 유의적으로 우수한 차이를 나타내었다.

• Journal of Life Science
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• v.8 no.5
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• pp.504-508
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• 1998

A study was conducted to evaluate a protein removal characteristics by foam separation. The foam separator was operated in well-mixed tank which would be considered as a completely mixed condition. The feasibility of foam separation to remove protein from fresh and sea water was investigated. Protein removal characteristics of the foam separator were obtained by batch reactor operations. To find the effect of the operating parameter to protein removal rate, the foam separation was carried with variation of initial protein concentration and foam height. The results indicated that the protein removal efficiency was increased with increasing protein concentration and decreased with increasing foam height. The relationship between protein concentration and protein removal rate was evaluated by linear regression.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.482-487
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• 2008

성능이 우수한 다성분계 전극을 개발하기 위하여 Ru를 주 전극성분으로 Pt, Sn, Sb 및 Gd를 보조 전극성분으로 하여 3, 4성분계 전극의 성능과 산화제 생성량 및 전극 표면 분석을 행하여 다음의 결과를 얻었다. 1. 2분 동안 단위 W당 제거된 RhB 농토는 Ru:Sn:Sb=9:1:1 > Ru:Pt:Gd=5:5:1 > Ru:Sn=9:1 > Ru:Sn:Gd=9:1:1 > Ru:Sb:Gd=9:1:1로 나타났다. Ru:Sn:Sb=9:1.1 전극에서 발생하는 free Cl, ClO$_2$ 및 H$_2$O$_2$농도가 다른 전극보다 높은 것으로 나타나 산화제 생성경향과 RhB 분해율과는 상관관계가 있는 것으로 사료되었다. 4성분계 전극 중에서 Ru:Sn:Sb:Gd 전극의 성능이 가장 우수한 것으로 나타났으나 3성분계 전극인 Ru:Sn:Sb=9:1.1 전극보다 성능이 떨어지는 것으로 나타났다. Ru:Sn:Sb=9:1:1 전극에서 생성되는 산화제 농도가 다른 두 종류의 산화제 농도보다 높은 것으로 나타났고 4성분 전극의 경우 Ru:Sn:Sb:Gd 전극의 산화제 농도가 Ru:Sn:Sb:Gd 전극이 높거나 유사한 경우로 나타나 산화제 생성 경향과 RhB분해 능과는 상관관계가 있는 것으로 나타났다. 초기 RhB 분해 속도가 높은 전극의 COD 제거율도 높은 것으로 나타났다. OH 라디칼은 발생하지 않지만 염소계 산화제 농도가 높고 RhB제거율이 높아 Ru를 주 성분으로 한 전극의 RhB분해는 주로 간접 산화작용에 의한 것이며, 개발된 3, 4성분계 산화물 전극은 간접 산화용 전극임을 알 수 있었다. 에칭을 하기 전의 Ti판은 표면이 매끄러운 것으로 나타났으며, 35% 염산으로 에칭한 후의 Ti메쉬는 매우 거친 표면조직을 가지는 것을 관찰할 수 있었다. Ru:Sn:Sb=9:1:1 전극과 Ru:Sn:Sb:Gd 전극의 SEM 사진을 관찰한 결과 두 전극 모두 전극 물질이 균일하게 도포되어 있었으며, 두 전극 모두 열소성을 통해 전극 성분을 코팅할 때 발생하는 "mud crack"이 발생한 것이 관찰되었다 EDX 분석에서 Cl이 관찰되었는데, 전극 성분의 불완전 산화로 인한 비양론적 산화물 때문이며 이는 RhB 분해성능과 관련 있는 것으로 사료되었다.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.46-146
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• 2003

해양환경의 대표적 오염물질인 PAHs가 양식굴의 생리대사에 미치는 영향을 파악하고자, 서로 다른 PAHs 농도에 노출된 굴의 여수율, 호흡율, 배설율 및 동화율의 변화를 조사하였다. 부착생물을 깨끗하게 제거한 굴을 실험실로 옮겨 3일정도 순치시키고, 이후 각각의 0, 50, 100, 200ppb의 농도별로 약 10일간 미리 노출시켰다. 이후 각 개체별로 2L 들이 2$0^{\circ}C$항온수조에서 0.2$\mu\textrm{m}$ 여과해수를 사용하여 실험하였다. 여수율은 Chaetoceros simplex를 지표생물로 하여 수조내 시간당 감소율을 구하여 Kim(1995)의 식에 의해 구하였다. 호흡율은 유동파라핀으로 외부와의 공기접촉을 단절시키고, 수조내 단위시간당 DO meter로 산소변화를 측정하여 Widdows and Johnson(1988)의 식을 변형하여 계산하였다. 배설율은 단위시간동안 수조내 NH$_4$-N 농도 증가량으로 조사하였고, NH$_4$-N은 HACH Inc.에서 제공하는 측정법을 따랐다. 여수율은 500ppb에서 다소 영향을 받아 증가하였다. 호흡율과 배설율은 노출농도가 증가함에 따라 증가하였지만, 50ppb와 100ppb에서는 다소 차이가 없었다. 따라서 양식굴이 PAHs와 같은 오염물질에 노출되었을 경우, 초기에는 여수율의 변화는 없고 배설율과 호흡율이 상승하여 체내 에너지 요구량이 증가하는 것으로 생각된다.

• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.187-194
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• 2017

This study was intended to evaluate the removal efficiency of nutrients in effluents of wastewater using microalgae. Microalgae used in the culture experiment collected in stream and reservoir located in Gyeongsangbuk-do. Dominant species in prior-culture tank were Monoraphidium contortum, Scenedesmus acutus, Coelastrum microporum and Chlorella sp. Dominant species in synthetic wastewater culture under the 4000 Lux and 8000 Lux were Chlorella sp. and Scenedesmus obliquus. The removal efficiency of $NO_3-N$ under the 4000 Lux and 8000 Lux were 27.2%~88.1% and 63.0%~83.6% respectively. The removal efficiency of $PO_4-P$ under the 4000 Lux and 8000 Lux showed above 93%. Removal efficiency of nutrients of $1.0{\times}10^6cells\;mL^{-1}$ inoculation concentration was more higher than that of nutrients of $1.0{\times}10^5cells\;mL^{-1}$ and $1.0{\times}10^7cells\;mL^{-1}$ inoculation concentration. Microalgae cultured in synthetic wastewater removed 94.9% of TN and 90.0% of TP. The removal rate of TN and TP in synthetic wastewater were $1.961mg\;L^{-1}\;day^{-1}$ and $0.200mg\;L^{-1}\;day^{-1}$ respectively. Nutrient removal efficiency of microalgae according to kinds of wastewater showed the highest in the private sewage.

• Journal of Korea Water Resources Association
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• v.32 no.2
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• pp.121-129
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• 1999

When the soil vapor extraction as a remediation method of contaminated soil and groundwater has been used, the effects of curtain wall, mode of pump operation and magnitude of extraction flowrate were examined by numerical simulation. Consequently, it was found that the removal rate was enhanced in case that the curtain wall was established around the extraction well with the extraction pumps operated alternatively. It was because that the removal of high density gas around the extraction well was possible. It was found that the removal efficiency of TCE gas did not depend on the extraction flowrate. However, the removal rate of TCE gas at varying extraction flowrate was not enhanced flowrate increase.