• 대한환경공학회지
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• 제28권8호
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• pp.852-859
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• 2006

Anammox(anaerobic ammonium oxidation)와 Canon(completely autotrophic nitrogen removal over nitrite) 공정과 같은 새로운 미생물학적 공정은 혐기성 소화 슬러지 상징수와 같은 고농도 암모늄 폐수로부터 효과적으로 질소를 제거할 수 있는 미생물학적 처리 기술이다. 본 연구에서는 합성폐수와 슬러지 소화조 상징수를 대상으로 상향류식 입상슬러지상 형태를 가진 새로운 Canon 형 질소 제거공정의 적용 가능성과 그 운전특성에 대하여 연구하였다. 이때 산소공급원으로 주입된 공기는 유출수 반송라인에 설치된 외부폭기조에서 공급하였다. 합성폐수(${\leq}110$ mg $NH_4$-N $L^{-1}$)를 사용한 첫 번째 실험에서는 유효 HRT 3.8일에서 약 95%의 암모늄(T-N 기준 92%)이 제거되었다. 또한 슬러지 소화 상징액($438{\pm}26$ mg $NH_4$-N $L^{-1}$)을 이용한 두 번째 실험에서는 유효 HRT 5.4일과 3.8일에서 각각 $94{\pm}1.7%$와 $76{\pm}1.5%$의 질소가 제거되었다. 두 실험 모두 유출수에서의 아질산염과 질산염 농도는 매우 낮게 검출되었다. 다른 미생물학적 질소 제거 신기술과 비교하였을 때 이 공정은 상당히 낮은 산소소모량($0.29{\sim}0.59$ g $O_2$ $g^{-1}N$)과 알칼리 소모($3.1{\sim}3.4$ g $CaCO_3$ $g^{-1}N$) 특성을 보였다. 이 공정은 또한 간단한 반응조 형상을 가지고 있으므로 효과적인 미생물 확보능력과 함께 시설투자 및 유지관리비용이 낮은 장점을 가지고 있다.

• 대한환경공학회지
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• 제22권12호
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• pp.2163-2173
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• 2000

메탄자화균에 의한 코발트 제거의 최적 pH 영역은 6.0~12.0이었으나 메탄자화균을 넣지 않은 blank는 10.5~11.5이었다. 코발트의 제거능은 pH에 크게 의존하였으나 blank보다는 민감하지 않았다. 초기 pH 6.0에서 1.0 g/L의 메탄자화균을 투입했을 때 170 mg Co/g biomass가 제거되었다. SEM 분석 결과에 의하면 코발트는 메탄자확균의 표면이나 세포의 분비 고분자에 흡착되어 제거된 것으로 사료된다. 초기 pH 6.0, 400 mg Co/L에서 메탄자화균의 최적의 투입량은 1.0 g/L이었다. 2.0 M NaCl과 $NaNO_3$의 높은 이온강도 하에서도 코발트 제거능은 그다지 영향을 받지 않았다.

• 한국환경보건학회지
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• 제31권1호
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• pp.15-22
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• 2005

This study was conducted to evaluate air injection mode on stabilization of solid waste in lysimeter. For three lysimeters, one was maintained under anaerobic condition as control, and air was injected into two lysimeters in continuous mode (atmospheric pressure) and intermittent mode (high pressure of 2 bar). Distilled water was sprayed over solid waste in 1.4 l/$m^3$(solid waste)/day, supposing rainfall intensity of 1,200 mm/yr and 30% infiltration. Oxygen in landfill gas was not detected in control lysimeter during operational days. After 30 day-aeration, oxygen concentrations of continuous and intermittent modes were maintained in 14% and 6%, respectively. $COD_{Cr}$ removal efficiencies of continuous and intermittent modes were about 70% and 50%, and BOD5 removal efficiencies were about 80% and 20%, respectively. In view of oxygen supply, and $COD_{Cr}$ and $BOD_5$ removal, continuous air injection mode of atmospheric pressure was more effective than intermittent mode of 2 bar. Settling degree of solid waste in case of two air injection modes was 3 times higher than that of anaerobic condition as control. Considering the above results, it was thought that air injection (especially continuous atmospheric pressure) could improve degradation of solid waste and induce preliminary stabilization in landfill site.

• Journal of Advanced Marine Engineering and Technology
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• 제33권2호
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• pp.322-329
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• 2009

Machinability of LAM(Laser Assisted Machining) has been studied for ceramics such as $Al_2O_3$, $Si_3_N4$ and $ZrO_2$ by $CO_2$ laser. It was possible to remove ceramics by PCBN tool because material became softening and deterioration by local laser beam irradiation. The advantage of LAM is the ability to produce larger material removal rates and tool life. But, for cutting of $Al_2O_3$ and $ZrO_2$, stage of laser power control was needed owing to thermal shock with high temperature of workpiece by laser power. And when $Si_3N_4$ was machined by LAM, $N_2$ gas spouted from surface of one cause of high temperature. Characteristics of LAM were analyzed using pyrometer, dynamometer, SEM and EDS to measure temperature of workpiece surface, cutting force, variation of machining surface and structure of lattice respectively. As the result of this study, it was found that machinability of LAM for ceramics in $CO_2$ laser and mechanism of LAM was different according to the kind of ceramics because of properties of materials.

• Membrane and Water Treatment
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• 제10권4호
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• pp.265-275
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• 2019

This study aimed to develop a compact partial nitritation step by forming granules with high Ammonia-Oxidizing Bacteria (AOB) fraction using the Air-lift Granulation Reactor (AGR) and to evaluate the feasibility of treating reject water with high ammonium content by combination with the Anammox process. The partial nitritation using AGR was achieved at high nitrogen loading rate ($2.25{\pm}0.05kg\;N\;m-3\;d^{-1}$). The important factors for successful partial nitritation at high nitrogen loading rate were relatively high pH (7.5~8), resulting in high free ammonia concentration ($1{\sim}10mg\;FA\;L^{-1}$) and highly enriched AOB granules accounting for 25% of the total bacteria population in the reactor. After the establishment of stable partial nitritation, an effluent $NO_2{^-}-N/NH_4{^+}-N$ ratio of $1.2{\pm}0.05$ was achieved, which was then fed into the Anammox reactor. A high nitrogen removal rate of $2.0k\; N\;m^{-3}\;d^{-1}$ was successfully achieved in the Anammox reactor. By controlling the nitrogen loading rate at the partial nitritation using AGR, the influent concentration ratio ($NO_2{^-}-N/NH_4{^+}-N=1.2{\pm}0.05$) required for the Anammox was controlled, thereby minimizing the inhibition effect of residual nitrite.

• 한국연초학회지
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• 제21권1호
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• pp.102-108
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• 1999

This study was conducted to evaluate the ventilation to remove gases, vapor and particles of environmental tobacco smoke(ETS) in a closed room. The ventilation rate choosed were 0.445 ㎥/min, 0.528 ㎥/min, and 0.625 ㎥/min. ETS components measured were total suspended particle(TSP), ultraviolet particulate matter(UVPM), fluorescent particulate matter(FPM), solanesol, carbon dioxide($CO_2$), carbon monoxide(CO), nicotine, and 3-ethenylpyri-dine(3-EP). The concentration of ETS components measured rapidly decreased as increasing ventilation rate, but the removal efficiency by ventilation was different from each ETS compounds. The $CO_2$, and CO, gaseous components of ETS, were dominant components to be removed from the room by ventilation. The ventilation with 0.528 ㎥/min for 1 hr was enough to remove over 99% of those gaseous components. Nicotine and 3-EP needed the ventilation for 2 hrs to reduce over 95 % of those components. As the same ventilation rate, 99 % of TSP and solanesol concentration were removed from the room within 2 hrs, UVPM and FPM concentration decreased 90 %.

• Nuclear Engineering and Technology
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• 제34권1호
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• pp.1-8
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• 2002

After kaolin clay was artificially contaminated with Co$^{2+}$ ion, the remediation characteristics were analyzed by the electrokinetic method. Ethanoic buffer was injected in the soil column and $CH_3$COOH was continuously inputted to the cathode reservoir to restrain the pH increase. Since the pH of the cathode side of the soil column was 4.0 initially and increased to only 6.5 after remediation for 43.6 hours, precipitate, Co(OH)$_2$, was not formed in the column. The effluent rate increased with the passage of time and Co$^{2+}$ removal in the column at the initial time were mainly controlled by ion migration. 13.1% of the total amount of Co$^{2+}$ in the soil column was removed in 10 hours, 46.8% of the total Co$^{2+}$ in 20.8 hours, 71.7% of the total Co$^{2+}$ in 30.1 hours, and 94.6% of the total Co$^{2+}$ in 43.6 hours. Meanwhile, residual concentrations in the column calculated by the developed model were similar to those by experiment. experiment.

• 공업화학
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• 제18권6호
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• pp.592-598
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• 2007

Temperature programmed desorption (TPD), XRD, SEM 및 FT-IR를 이용하여 코발트 프탈로시아닌 유도체의 황과 아민화합물에 대한 흡착효율을 조사하였다. 코발트 프탈로시아닌 유도체의 암모니아에 대한 TPD 측정결과, 산도가 낮은 온도($100{\sim}150^{\circ}C$)와 높은 온도($350{\sim}400^{\circ}C$)에서 두개의 탈착피크가 나타났다. 테트라카르복실 코발트프탈로시아닌(Co-TCPC)은 코발트 프탈로시아닌(Co-PC)보다 낮은 온도(물리적 흡착)에서 탈착피크가 약했지만 높은 온도(화학적 흡착)에서 강한 탈착피크가 나타났다. Co-TCPC와 Co-PC의 비표면적은 각각 37.5와 $18.4m^2/g$이었다. Co-TCPC와 Co-PC의 기공부피는 각각 0.17과 $0.10cm^3/g$이었다. 파과곡선으로부터 흡착용량을 계산하였더니 트리에틸 아민 가스 120 ppm의 평형농도에서 Co-TCPC의 흡착용량은 24.3 mmol/g, Co-PC의 흡착용량은 0.8 mmol/g로 나타났다. Co-TCPC와 Co-PC로 디메틸 술파이드 제거효율은 디메틸 술파이드 초기농도 225 ppm에서 각각 92와 18% 제거효율을 보였다. Co-TCPC와 Co-PC로 트리메틸아민 제거효율은 트리메틸아민 초기농도 118 ppm에서 각각 100.0%와 17.0% 제거효율을 보였다.

• 한국환경과학회지
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• 제17권10호
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• pp.1147-1154
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• 2008

Road runoff, one of non-point source pollutants, contains various heavy metals, most of which flow into discharge waters without being treated. The mechanism of removing the heavy metals in water is similar to that of removing micro-particles. Therefore, it is considered that it is possible to remove a lot of the heavy metals contained in the road runoff by filtering or absorbing them. In this paper, performed has been a basic study on the characteristics of UNFS (Up Flow Non-Point Source Filtering System) using carbide pellet and zeolite pellet as double-layer filtering mediums to treat the road runoff. The removal rate with filtering and absorption time has been shown as follows: 29.0% for Cr; 27.8% for Cd; 25.7% for Fe; 25.4% for Co; 21.2% for Pb; ]9.6% for Zn; 18.2% for Al; 17.0% for Mn; 11.3% for Ni; 7.5% for Cu. The overall removal rate according to influx change has been shown to be approximately 30%, and the load of heavy metals flowing out in initial precipitation could be reduced by using carbide as a recycling filtering medium. When the removal as coarse particles settle is added up, it is expected that UNFS will result in a higher removal rate.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.321-327
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• 2003

[ $CO_2$ ] sequestration in oil reservoirs can be one of the most effective strategies for long-term removal of greenhouse gas from atmosphere. This paper presents an advantage of the localized nonlinear approximation of integral equation solutions for inverting crosswell electromagnetic data, which are observed as a part of pilot project of $CO_2$ flooding at the Lost Hills oil field in central California, U.S.A. To monitor the migration of $CO_2$, we have used 2-D cylindrically symmetric and 2.5-D tomographic inversion methods. These two schemes produce nearly the same images if the borehole separation is large compared with the skin depth. However, since the borehole separation is much less than five skin depths in this $CO_2$ injection experiment, the 2.5-D model seems to be more reliable than the 2-D model. In fact, the pre-injection 2.5-D image is more successfully compared with induction logs observed in the two wells than the 2-D model. From the time-lapse crosswell imaging, we can confirm the replacement of brine with $CO_2$ makes a decrease of conductivity.