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관내 혼화장치의 오리피스 형상과 개수에 따른 혼화 및 유동특성
정선용(Jeong, Seon Yong),정원식(Chung, Won Sik),이석호(Rhi, Seok Ho),이계복(Lee, Kye Bock),이대규(Lee, Dae Gyu) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.2
본 연구에서는 혼화기의 혼화성능과 압력손실을 개선하기 위해 오리피스의 형상과 개수에 따른 영향을 해석하였다. 물의 정수에서 중요한 과정은 물속의 이물질을 포집하는 응집 과정이고 응집제가 얼마나 물속에 고른 분포를 가지고 물속에 혼화되어 있는 지가 정수에 큰 영향을 미친다. 기계식 혼화방식이 갖는 정수과정에서의 긴 체류시간, 기계 소음, 과다한 에너지의 소비 및 높은 유지관리 비용 등의 단점을 보완하기 위해서 최근에는 응집제가 원수에 주입됨과 동시에 가능한 한 빠르게 수중에 확산시킬 수 있는 장치로서 관내혼화장치의 도입이 증가추세에 있다. 본 연구에서는 관내 혼화기의 혼화성능과 압력손실을 개선하기 위해 오리피스의 유무, 형상과 개수에 따른 약품의 체적분률, 관내 압력손실 등 유동특성과 체적분률이 수치해석에 의해 계산된다. 관내 혼화장치에 장착된 오리피스는 혼화정도를 향상시키나 압력손실이 증가되므로 오리피스의 개수를 제한하여야 한다. 주요 인자에 대한 민감도 분석을 통해 가이드 베인을 장착한 오리피스 1개를 사용하여 약품의 체적분률과 압력손실이 개선된 관내 혼화장치를 제안하였다. This study examines the effect of the type and number of orifices in an in-line mixer to improve the mixing performance and pressure loss. Recently, in-line non-power-consuming mixers have been increasingly used to complement mechanical mixers, which have a long dwell time, noise, excessive energy consumption, and high maintenance costs. An in-line mixer with an orifice for efficient mixing in water treatment was examined by numerical analysis using the commercial code FLUENT. The flow characteristics of pressure loss and velocity distribution within the mixer and the mixing efficiency were compared with and without the orifices. The CFD results show that the mixing efficiency was improved, but the pressure loss was increased by the in-line mixer with an orifice. A sensitivity study was also done on the principal parameters.
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Biofilm 생성이 토양흡착 나프탈렌 분해에 미치는 영향
이광춘,정선용,박정훈,Li, Guang-Chun,Chung, Seon-Yong,Park, Jeong-Hun 한국지하수토양환경학회 2009 지하수토양환경 Vol.14 No.6
Naphthalene-degrading bacteria Pseudomonas aeruginosa CZ6 isolated from contaminated soil can adhere to crystal naphthalene and produce extracellular polymeric substance. LB, YM and MSM medium were used as culture mediums to investigate the formation of biofilm. Biofilm was developed the most in LB medium by Pseudomonas aeruginosa CZ6. In the culture, strain CZ6 growth was rarely affected by naphthalene concentration. Optimal culture condition was $30^{\circ}C$ and pH 7 at 0.10% substrate and 150 rpm shaking. The effect of culture medium on naphthalene degradation in the two soil slurry system was evaluated. The initial degradation rate of naphthalene was highest in the MSM medium of soil slurry. However, the sorbed naphthalene was rapidly degraded at the LB medium when naphthalene availability in liquid was limited. The results of this study suggest that biofilm formation and extracellular polymeric substance production increased bioavailability of soil sorbed naphthalene. 나프탈렌 분해균주인 Pseudomonas aeruginosa CZ6을 오염된 토양에서 분리하였으며 분리된 균주는 결정상태의 나프탈렌에 부착하고 그 주변에 extracellular polymeric substance를 분비하는 특성을 가졌다. LB, YM과 MSM 배지를 사용하여 배지의 종류에 따른 biofilm 생성량을 측정한 결과, LB 배지에서 biofilm이 가장 많이 생성되는 것으로 나타났다. 나프탈렌을 기질로 한 배양조건에서 균주는 기질의 농도 영향을 크게 받지 않고 0.10% 기질, 150 rpm 조건에서 최적 배양조건은 $30^{\circ}C$, pH 7로 나타났다. 두 가지 토양에서 배지의 종류에 따른 나프탈렌의 분해특성을 관찰한 결과 초기에는 MSM 배지에서 나프탈렌이 가장 많이 분해가 되었다. 그러나 생물이용성이 제한을 받는 조건에서 LB 배지의 나프탈렌이 가장 빨리 제거가 되었다. 이런 결과는 biofilm의 형성과 extracellular polymeric substance 생성이 토양에 흡착된 잔류 나프탈렌의 생물학적 이용성을 향상시키기 때문인 것으로 사료된다.
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강창민,정선용,Kang, Chang-Min,Chung, Seon-Yong 한국환경보건학회 2008 한국환경보건학회지 Vol.34 No.3
This study was conducted to analyse the effects of the UFCA for treating polluted water in a reservoir. The UFCA mixes water by circulation of surface and bottom water layers. The circulation supplies oxygen to bottom of the reservoir, resulting in water quality improvement. With a UFCA in use, we surveyed the changes of temperature, pH, transparency, depth, conductivity, DO, COD, BOD, T-N, T-P and Chlorophyll-a for 7 months from Feb. to Aug. in 2004 in our experimental reservoir. There was little difference in the surface and bottom temperatures of the reservoir because of water mixing by the UFCA. However, pH was changed from 7 to 9. The transparency of water was about 80 cm through the all periods. Conductivity was $150\;{\mu}S/cm$ in early Feb., but increased to $270\;{\mu}S/cm$ in early March. Little change was seen in DO with depth, but it was maintained above 6 mg/l in June and July. BOD increased from 2.1 to 12.2 mg/l. The study reservoir did not undergo any eutrophication during the period of our experiment, but the comparison reservoir had an algae-bloom. The COD in the experimental reservoir increased from 5.4 to 14.5 mg/l. The COD concentration of the experimental reservoir was higher than comparison reservoir at the beginning of the study but in August this situation was reversed. SS concentration increased from 13.5 to 23.5 mg/l in Feb., but it fell from between 8.5 to 11.2 mg/l in July. T-N was increased from 1.3 to 4.9 mg/l. It increased up to 3 times in the rainy season as compared to other components. However the comparison reservoir increased up to 40 times higher than the experimental reservoir in the same period. T-P increased from 0.04 to 0.17 mg/l. The ratio of T-N to T-P increased from 20:1 to 40:1 which means that T-P was a growth limiting factor for algae and aquatic plants. Chlorophyll-a increased from 20 to 120 mg/l, and its concentration was correlated with T-P, such that Chlorophyl-a concentration increased with increased of T-P concentration. The concentrations of COD, T-N, T-P and other parameters were higher in the experimental reservoir than in the comparison reservoir but this situation was reversed in July, when the most severe eutophication occurred. The results show that overall the experimental reservoir was greatly remedied by UFCA. The UFCA accelerated the degradation of aquatic organic materials through effective supply of air with up-flow and circulation of water. We conclude that the UFCA can be very effective in aspect of the remediation of water quality incontaminated reservoirs and lakes.
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이윤국,이주리,정선용,박정훈,Lee, Youn-Goog,Lee, Ju-Ry,Chung, Seon-Yong,Park, Jeong-Hun 한국지하수토양환경학회 2008 지하수토양환경 Vol.13 No.2
오염물질이 토양에 흡착 또는 탈착하는 성질은 지하계에서 오염물질의 이동과 거동에 큰영향을 미친다. 아트라진을 대상으로 광주지역 7가지 토양을 이용하여 흡착 및 탈착특성을 조사하였다. 토양의 유기탄소함량 (organic carbon content)은 $0.42{\sim}2.82%$의 범위였으며, 아트라진의 토양분배계수 ($K_d$)는 $0.48{\sim}3.26\;l/kg$의 범위였다. 경방 토양과 용동토양을 제외한 나머지 토양들은 유기탄소함량이 증가함에 따라 $K_d$ 값은 증가하였다. Three site desortpion model을 이용하여 평형 탈착분율, 비평형 탈착분율, 비탈착 분율 그리고 탈착속도계수를 구하였다. 실험한 모든 토양에서 아트라진의 비탈착 분율이 산출되었고, 다단탈착 실험에서도 탈착되지 않는 아트라진이 토양에 존재하였다. 다단 탈착 실험에서 흡착 등온선과 탈착 등온선이 일치하지 않는 이력현상이 나타났다. Sorption and desorption processes play an important role in the transport and fate of organic contaminants in subsurface system. In this study, sorption and desorption characteristics of atrazine in 7 soils selected at the Gwangju area were investigated. Soil organic carbon contents ranged from 0.42 to 2.82%. Sorption and desorption experiments were performed in batch slurries. Sorption distribution coefficient ($K_d$) of atrazine were ranged from 0.48 to 3.26 l/kg and $K_d$ value increased with increasing organic carbon contents except of Kyongbang and Youngdong soils. Single desorption data were analyzed by the three-site desorption model including equilibrium, non-equilibrium and non-desorbable site. Non-desorbable site fractions of atrazine in all soils were enumerated and non-desorbable atrazine was observed in seriesdilution desorption experiment. Sorption/desorption hysteresis was also observed in the series-dilution desorption experiment.
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이광춘,정선국,정선용,조영태,박정훈,Li, Guang-Chun,Jung, Sun-Kook,Chung, Seon-Yong,Jo, Young-Tae,Park, Jeong-Hun 한국지하수토양환경학회 2011 지하수토양환경 Vol.16 No.3
The experimental studies for remediation of diesel contaminated soils were performed using subcritical water in laboratory scale. Contaminated soils from industrial area and artificially contaminated soils were utilized for soil remediation. Experimental system was composed for subcritical water to flow upward through the soil packed column for extracting contaminants. 10 g of contaminated soil was packed into the column and water flow rate was 2 mL/min. To evaluate the effects of temperature, pressure and treatment time on the removal efficiency, temperature was changed from 100$^{\circ}C$ to 350$^{\circ}C$, pressure from 50 bar to 220 bar and treatment time at the predetermined temperature from 0 min to 120 min. The purification efficiency increased as temperature increased. However, the effect of pressure and treatment time was low. Temperature 250$^{\circ}C$, pressure 50 bar and treatment time 30 min were selected for optimal operating condition for this study.
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전라남도 지역의 하천수에 존재하는 내분비 장애물질(Bisphenol A와 Styrene oligomer)의 실태조사
박송인 ( Song In Park ),정선용 ( Seon Yong Chung ),( Saido Kstsuhiko ),( Sato Hideto ),나숙현 ( Suk Hyun Na ) 한국물환경학회 2012 한국물환경학회지 Vol.28 No.5
Recently, there have been active researches regarding endocrine-disrupting chemicals (EDCs). In this study, fifteen small freshwater streams in Cholla-namdo province, South Korea were investigated with respect to the concentration of the endocrine disruptors - Bisphenol A (BPA), styrene monomer (SM), styrene dimer (SD), and styrene trimer (ST) by gas chromatography-mass spectrometry (GC-MS). Measured concentration of the target compounds in the sampled water ranged from <ND to 5.03 ng/mL, <ND to 0.1 ng/mL, <ND to 0.04 ng/mL, and ND to 0.45 ng/mL for BPA, SM, SD, and ST, respectively. The endocrine disruptors analysis of the water samples showed that the concentration of BPA and ST were much higher than the other two compounds. These results imply that the streams of Cholla-namdo province were contaminated by materials generated from decomposition of polystyrene (PS) chemically and physically.
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