• 대한환경공학회지
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• 제30권7호
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• pp.683-687
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• 2008

수중에 포함된 진흙 및 흙탕물 등의 부유물질을 제거하기 위해 자연 침강방법을 이용할 경우 수처리 시간이 장시간 소요됨으로써, 거대설비가 필요할 뿐만 아니라 이에 따른 많은 인력이 동원되어야 한다는 단점을 가지고 있다. 따라서 본 연구에서는 진흙 및 흙탕물 등의 부유물질을 제거하기 위한 방법으로 자성분말체를 이용하여 황토수의 부유물질을 고속으로 제거하기 위한 조건을 확인하였다. 부유물질이 0.3%인 황토수의 부유물질을 고효율적으로 제거하기 위해서는 수중의 pH가 7.0$\sim$7.5, 마그네타이트의 자성분말체가 0.1$\sim$0.2%, 무기응집제인 황산알루미늄이 알루미늄으로서 13 ppm, 아크릴아마이드 계열의 고분자응집제 0.5 ppm의 농도를 유지함으로써, 황토수의 부유물질 제거율이 극대화되었다.

• 한국지반환경공학회 논문집
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• 제11권8호
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• pp.25-32
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• 2010

석유계 탄화수소 화합물로 인한 토양과 지하수 오염은 환경과 건강에 영향을 미치는 주된 원인으로 제기되어 왔다. 이러한 오염물질들은 흡착포, 활성탄 또는 중력 방식의 유수분리 장치 등을 이용하여 처리하고 있다. 하지만 이러한 경우 자유상 유류(free product)로 존재하는 경우에는 효과적이나 에멀젼 상태의 유류는 제거할 수 없는 것으로 알려져 있다. 따라서 본 연구에서는 굴착시 예상되는 지하수의 고농도 현탁성 고형물로 인한 지하수 처리시 문제점과 TPH(Total Petroleum Hydrocarbon)를 어떻게 효율적으로 제거할 수 있는지 방안을 제시하고자 한다. 고분자 폴리머를 사용하여 혼화 응집 실험을 수행한 결과 5분 이내에 SS(Suspended Solids)와 COD(Chemical Oxygen Demand) 농도가 지하수 수질 기준을 만족하는 것을 나타났으나, TPH 농도는 방류수 수질 기준을 만족하지 못하는 것으로 나타났다. DAF(Dissolved Air Flotation) 실험 결과 단일 DAF 공정으로는 방류수 수질 기준을 만족하지는 못하였다. 단일 DAF 반응조를 이용하여 DAF와 혼화 응집 반응을 동시에 수행하는 경우 20분에 모든 기준을 만족하는 것으로 나타났다.

• 대한기계학회논문집
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• 제6권4호
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• pp.308-314
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• 1982

An experimental study has been made for the dispersion phenomena by a stochastic model in a turbulent pipe flow. Local instantaneous passage of suspended solid particles were recorded in two dimensions, employing a periscopic system coupled vidicon camera. Probability density of passage was calculated. Second moment shows qualitatively that dispersive action is dependent on particle's geometric characteristics in vertical pipe flow. In case that density of the solid particles is larger than that of liquid, particles have a tendency to approach from the center of pipe to the wall, and in the contrary case the approach the center of pipe. It seems that there exists a field of radial accelerations, centrifugal or centripetal according to the sign of density difference between two phases.

• Environmental Analysis Health and Toxicology
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• 제7권3_4호
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• pp.81-84
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• 1992

Physical compositions of solid waste in Wonju, shopping area were investigated with combustibles 78.13% (papers 35.89%, foods 14.41% etc.) incombustibles 21.87% (glass and ceramics 11.02%, metals 6.0% etc.) in 1991, solid waste in apartment area were investigated with combustibles 84.27% (foods 34.29%, papers 22.58% etc.), incombustibles 15.73% (glass and ceramics 8.77%, metals 4.85% etc.) and residence area were characterised with combustibles 70.37% (foods 33.55% , papers 10.53% etc.) and incombustibles 29.63% (ash of briquet 17.29%, glass and ceramics 7.49% etc.). Water qualities of a leachate from municipal landfill of Wonju city were analysed pH 8.0~8.4, total suspended solid 102~140 mg/1, CN￣ 0.003~ 0.008 mg/1, NO$_2$-N 0.108~0.294 mg/1 and phenols 0.46~1.12 mg/1. Volume of the leachate for 20% methemoglobin formation were 0.2~0.4 mg/ml in Octever, 0.3~0.4 ml/ml in December sampling, 0.2~0.3 ml/ml in St.1 and 0.4 ml/ml in St.3.

• 센서학회지
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• 제8권4호
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• pp.314-319
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• 1999

공기중의 먼지를 수정진동자를 이용한 미량저울을 써서 측정하는 실험을 수행하였다. 측정장치를 컴퓨터에 연결하여 여러 개의 센서를 활용함으로서 동시측정이 가능한 장치를 만들었다. 본 연구에서는 실험장치의 구체적인 사항을 자세히 설명하여 비슷한 장치를 이용한 다른 유사한 실험에 활용하는 데 도움을 주고자 하였다. 연구의 결과 본 측정시스템이 공기 중 먼지농도의 연속측정에 적합함을 알 수 있었다.

• 한국수산과학회지
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• 제40권2호
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• pp.73-78
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• 2007

The suitability of a flexible fiber filter for removing suspended solid (SS) in a recirculating aquaculture system was evaluated. This study focused on variation in the performance with a change in filtering time, influent water quality, and filtering mode duration. The particle distribution diagram of the filter effluent showed that the number of particles bigger than $5-8{\mu}m$ decreased dramatically, and the removal efficiency exceeded 80%. Although the removal efficiencies of SS and chemical oxygen demand (COD) were dependent on the quality of the influent, the SS and COD concentrations of the effluent were not affected by the influent concentrations. This was despite the deterioration if water quality after feeding in the rearing tank. The performance of the filter was not affected by the filtering mode duration, feeding conditions, or filtering time. The SS concentration and turbidity of the recirculating-type rearing tank were 30% and 50% lower, respectively, than of the a non-recirculating-type rearing tank under the same operating conditions. The flexible fiber filter was applicable to a recirculating aquaculture system that uses plenty of seawater, based on its low filtering resistance $(2kg_f/cm^2)$, high flux $(330m^3/m^2/hr)$, and high fine particle removal efficiency (80%, $5-8{\mu}m$).

• 한국환경복원기술학회지
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• 제7권1호
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• pp.97-109
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• 2004

The disposal of stormwater is one of the major problems in urban water management. One method of reducing peak runoff rates and other detrimental impacts of stormwater is detention storage. Detention ponds as a water quality control alternatives have been investigated by a number of researchers. Recognizing multiple roles such as flood peak attenuation, pollution removal and aesthetic enhancement, the design and management of detentions ponds deserve more research. The purpose of this research is to establish design criteria wet detention ponds to improve water quality. Water quality in detention pond discharge might be improve with physical, chemical and biological alterations. Physical alteration was focused in this study. There are several methods for estimating the suspended solid control capability of wet detention ponds. Existing models of suspended solids removal are based on sedimentation and gravity settling theory. The pollutant trap efficiency of pond is a function of several interrelating factors. Detention time is the most important factor, because it determine gravity settling quantities of pollutants. Desirable modification of physical factors for improvement of water quality in wet detention ponds are volume ratio, area ratio, length to width ratio, depth, out let location, bottom soil type. In order to apply design procedure in actual site, Namak new town development area was selected.

• 설비공학논문집
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• 제22권11호
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• pp.727-734
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• 2010

The present study numerically investigates the motion of a solid body suspended in the square enclosure with natural convection. A two-dimensional circular cylinder levitated thermally has been simulated by using thermal lattice Boltzmann method(TLBM) with the direct-forcing immersed boundary method. To deal with the ascending, falling or levitation of a circular cylinder in natural convection, the immersed boundary method is expanded and coupled with the TLBM. The circular cylinder is located at the bottom of a square enclosure with no restriction on the motion and freely migrates due to the Boussinesq approximation which is employed for the coupling between the flow and temperature fields. For different density ratio between the cylinder and the fluid, the motion characteristics of the circular cylinder for various Grashof numbers have been carried out. The Prandtl number is fixed as 0.7.

• 한국환경과학회지
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• 제22권1호
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• pp.1-6
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• 2013

A fixed biofilm reactor system composed of anaerobic, anoxic(1), anoxic(2), aerobic(1) and aerobic(2) reactor was packed with synthetic activated ceramic (SAC) media and adopted to reduce the inhibition effect of low temperature on nitrification activities. The changes of nitrification activity at different wastewater temperature were investigated through the evaluation of temperature coefficient, volatile attached solid (VAS), specific nitrification rate and alkalinity consumption. Operating temperature was varied from 20 to $5^{\circ}C$. In this biofilm system, the specific nitrification rates of $15^{\circ}C$, $10^{\circ}C$ and $5^{\circ}C$ were 0.972, 0.859 and 0.613 when the specific nitrification rate of $20^{\circ}C$ was assumed to 1.00. Moreover the nitrification activity was also observed at $5^{\circ}C$ which is lower temperature than the critical temperature condition for the microorganism of activated sludge system. The specific amount of volatile attached solid (VAS) on media was maintained the range of 13.6-12.5 mg VAS/g media at $20{\sim}10^{\circ}C$. As the temperature was downed to $5^{\circ}C$, VAS was rapidly decreased to 10.9 mg VAS/g media and effluent suspended solids was increased from 3.2 mg/L to 12.0 mg/L due to the detachment of microorganism from SAC media. And alkalinity consumption was lower than theoretical value with 5.23 mg as $CaCO_3$/mg ${NH_4}^+$-N removal at $20^{\circ}C$. Temperature coefficient (${\Theta}$) of nitrification rate ($20^{\circ}C{\sim}5^{\circ}C$) was 1.033. Therefore, this fixed film nitrogen removal process showed superior stability for low temperature condition than conventional suspended growth process.

• Environmental Engineering Research
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• 제24권2호
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• pp.263-270
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• 2019

Palm oil mill effluent (POME) is the largest pollutant discharged into the rivers of Malaysia. Thus UF membrane study was conducted to investigate the effect of pressure and stirring speed on performance of POME treatment and fouling of membrane. Two types of membrane polyethersulfone (PES) and regenerated cellulose (RC) with molecular weight cut-off (MWCO) 5 and 10 kDa were used in this study. Results showed that, as pressure increased, fouling increased however permeate quality improved, the best pressure was 1.0 bar, where the fouling was not too high and produce good permeate quality. As stirring speed increased, fouling reduced and permeate quality improved, however, when stirring speed increased from 600 rpm to 800 rpm, there was no significant improvement on the permeate quality. Therefore, the best condition was at 1.0 bar and 600 rpm. PES membrane with MWCO 5 kDa showed the best permeate quality, even fouling slightly higher than RC membrane. The permeate quality obtained were analyzed in term of dissolved solid, turbidity, suspended solid, biological oxygen demand ($BOD_5$) and chemical oxygen demand (COD) were 538 mg/L, 1.02 NTU, < 25 mg/L, 27.7 mg/L and 62.8 mg/L, respectively with dominant type of fouling is cake resistance. Thus, it can be concluded water reuse standard was successfully achieved in terms of $BOD_5$ and suspended solid.