• 한국환경보건학회지
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• 제33권4호
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• pp.293-298
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• 2007

The microorganism for ammonia gas removal was isolated from composting product. This was identified as Brevundimonas diminuta by morphological, biochemical characteristics study and 16S rDNA sequence analysis. Optimal incubation temperature for cell growth and oxidizing ability of $NH_4-N$ was $30^{\circ}C$ and optimal initial pH was 7. Glucose affected the growth of cell and the removal of $NH4^+$. The growth rate of the isolates were increased when grown in the presence of 0.05-1%(w/v) glucose in the selective medium and lurker increases in glucose concentration to 2% caused significant decreases in the cell growth and oxidizing ability of $NH4^+$.

• 한국의류학회지
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• 제7권2호
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• pp.19-25
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• 1983

The purpose of this study was to investigate the effects of laundry variables and additives on the removal of deposited calcium on the cotton fabric. Samples of calcium deposited fabric was made by treating fabric with $CaC1_2$ and $Na_2CO_3$ solution subsequently. The experimental variables were: 1) NaOH concentration ($0.0001\%$, $0.0005\%$, $0.001\%$, $0.005\%$, $0.01\%$) 2) Alkaline builders(sodium carbonate, sodium meta silicate) 3) Sequestering agents(STPP and EDTA concentration: $0.02\%$, $0.04\%$, $0.06\%$, $0.08\%$, $0.1\%$, $0.15\%$, $0.2\%$) 4) Temperatures($25\pm1^{\circ}C$, $40\pm1^{\circ}C$, $60\pm1^{\circ}C$) 5) Edge-abrasion to the removal of deposited calcium on the cotton fabric. The fabric was washed for 15 minutes in a washing machine(Model: Gold Star WP-3007) or Launder-0-meter(40$\~$45 r.p.m., Toyo Rika Instrument Inc.) and rinsed 3 times per every rinsing time. The amount of calcium deposits on the fabrics was determined by EDTA-back titration methods and edge-abrasion was evaluated by ASTM D 3886 method. The results of this study were as follows: 1) pH of surfactant solution(NaOH concentration) did not influence on the removal of deposited calcium on the cotton fabric. 2) Added alkaline builders did not influence on the removal of deposited calcium on the cotton fabric. 3) It was shown that STPP and EDTA were effective to remove deposited calcium. The removal of deposited calcium on the cotton fabric was proportionally increased with increasing concentration of STPP and EDTA. At high concentration, however, the rate was rather decreased with increasing concentration. 4) The temperature of washing solution did not influence on the removal of dedosited calcium on the cotton fabric. 5) As the removal of deposited calcium on the cotton fabric was increased, the rate of edge-abrasion of the fabric was gradually increased.

• 미생물학회지
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• 제45권4호
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• pp.362-367
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• 2009

대청호의 한 지류인 소옥천으로부터 고효율 조류억제 세균을 분리하기 위하여 176균주를 분리 스크린하였으며, 이 중 AJ1이 가장 높은 조류성장억제능을 나타내었다(지름 50.0 mm 성장억제환). 조류성장억제능이 높았던 AJ1 균주 동정을 위하여 형태학적, 생리 생화학적, 16S rRNA gene sequence 분석, 지방산 분석을 수행하였으며 그 결과, Pseudomonas aeruginosa 로 판별되었다. AJ1 배양액을 원심분리한 후 상등액을 조류배양액에 첨가 시, 상등액에 의한 조류성장억제능이 나타남에 따라 세포 외 물질 분비에 의한 것을 확인할 수 있었다. 가장 높은 조류성장억 제능[60.2(${\pm}$1.3)%]은 탄소원으로 mannitol을 사용하고, 온도 $30^{\circ}C$, pH 8에서 배양할 때 보였다. 또한, AJ1 균주의 배양기간 및 투여시기에 따른 조류성장억제능 평가 결과, 조류 성장 초기 단계에 조류성장억제균을 투여하였을 때 조류성장억제능이 높게 나타났고, 균주의 배양기간에 따른 조류성장억제능은 연관성이 나타나지 않았다. 상등액 접종량에 따른 조류성장억제능은 상등액의 접종량이 높아질수록 M. aeruginosa의 제거량은 증가하였으며, 고농도(40ml/L)로 적용하였을 때 80.3(${\pm}$8.6)%의 가장 높은 M. aeruginosa 제거효율을 보여주었다. 제거 속도의 경우 상등액 접종량이 낮아질수록 M. aeruginosa 제거율이 높아지는 경향을 확인하였으며, 저농도(10 ml/L)로 적용시 $8.2{\mu}g$ chl-a/supernatant ml/day로 가장 높게 나타났다. 본 연구 결과, AJ1 균주의 현장 적용 시 M. aeruginosa의 제어에 효율적일 것으로 사료된다.

• 공업화학
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• 제27권5호
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• pp.532-536
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• 2016

본 연구에서는 하수 슬러지를 대상으로 단상 고온($55^{\circ}C$)과 중온($35^{\circ}C$) 혐기성 소화조의 안정성, 고형물 제거 및 메탄생성을 관찰하였다. 실험 결과 별도의 pH 조절 없이 고온($R_{TAD}$, reactor of thermophilic anaerobic digestion) 및 중온 ($R_{MAD}$, reactor of mesophilic anaerobic digestion) 소화조 내 pH의 경우 혐기 소화 시 안정적인 미생물 활성을 나타낸다고 알려진 6.5-8.0 사이의 값을 소화 기간 내내 유지하는 것을 관찰할 수 있었다. 또한, total alkalinity (TA)의 경우 $R_{TAD}$ 및 $R_{MAD}$ 모두 3-4 g $CaCO_3/L$의 높은 값을 안정적으로 유지하였다. 고형물 제거의 경우 순응 기간 후 $R_{TAD}$에서 43.3%, $R_{MAD}$에서 33.6%의 VS 제거율을 보이며 $R_{TAD}$에서 약 10% 높은 VS 제거율은 제거율을 보였다. 유기산의 경우 $R_{TAD}$ 및 $R_{MAD}$에서 순응 기간 직후 검출되지 않았다. $R_{TAD}$ 및 $R_{MAD}$ 모두 순응 기간 후 안정적인 메탄 생성을 보였으며, $R_{TAD}$에서 $R_{MAD}$에 비해 31.4% 향상된 메탄 생성률이 관찰되었다($R_{TAD}$; 243 mL $CH_4/L/d$; $R_{MAD}$ : 185 mL $CH_4/L/d$). 반면, 두소화조 $R_{TAD}$ 및 $R_{MAD}$에서의 메탄 수율은 유사한 값을 보였다.

• 자원리싸이클링
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• 제23권5호
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• pp.55-61
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• 2014

As의 평균함량이 285 mg/kg인 상동광산 광물찌꺼기의 As제거를 위한 부유선별에서 인산염 첨가에 따른 영향을 알아보기 위해 제3인산나트륨(이하 T.S.P)을 분산제로 첨가하여 부유선별을 실시하였다. 먼저 분산제 없이 부유선별을 진행한 결과, As제거율은 88.7%, 부상물의 무게비는 2.52%였고 추가적으로 T.S.P를 첨가하여 부유선별을 실시한 결과 각각 92.74%, 2.26%로 As제거율은 증가하고 부상물의 무게비는 감소하였다. 두 실험의 부상물을 대상으로 입도분석을 진행한 결과, T.S.P를 첨가하지 않은 부상물은 평균입도가 19.34 um, 10 um이하의 양이 전체의 40.2%인 반면 T.S.P를 첨가할 경우, 각각 176.8 um, 6.5%였으며 이를 통해 미립입자의 부유가 억제되었음을 확인하였다. 또한 X.R.F 분석을 통해 두 실험 부상물의 실리카($SiO_2$)함량을 비교해본 결과, T.S.P를 첨가하지 않은 경우 42.74%, 첨가한 부상물의 경우 29.56%로 실리카계열의 친수성입자가 효과적으로 분산되어 부유가 억제되는 결과를 확인하였다.

• Advances in environmental research
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• 제3권3호
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• pp.231-251
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• 2014

The present study examines the phosphate adsorption potential and behavior of mixture of Ground Burnt Patties (GBP), a solid waste generated from cooking fuel used in earthen stoves and Red Soil (RS), a natural substance in fixed bed column mode operation. The characterization of adsorbent was done by Proton Induced X-ray Emission (PIXE), and Proton Induced ${\gamma}$-ray Emission (PIGE) methods. The FTIR spectroscopy of spent adsorbent reveals the presence of absorbance peak at $1127cm^{-1}$ which appears due to P = O stretching, thus confirming phosphate adsorption. The effects of bed height (10, 15 and 20 cm), flow rate (2.5, 5 and 7.5 mL/min) and initial phosphate concentration (5 and 15 mg/L) on breakthrough curves were explored. Both the breakthrough and exhaustion time increased with increase in bed depth, decrease in flow rate and influent concentration. Thomas model, Yoon-Nelson model and Modified Dose Response model were used to fit the column adsorption data using nonlinear regression analysis while Bed Depth Service Time model followed linear regression analysis under different experimental condition to evaluate model parameters that are useful in scale up of the process. The values of correlation coefficient ($R^2$) and the Sum of Square Error (SSE) revealed the Modified Dose Response model as the best fitted model to the experimental data. The adsorbent mixture responded effectively to the desorption and reusability experiment. The results of this finding advocated that mixture of GBP and RS can be used as a low cost, highly efficient adsorbent for phosphate removal from aqueous solution.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E3호
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• pp.165-174
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• 2002

A dual -column biofilter system with two different composts was used to investigate the macro-kinetics of dim-ethyl disulfide (DMDS) degradation. The biofilter columns were filled with compost mixtures up to one meter, The gas How rate and DMDS concentration to the biofilters were varied to study their effect on the removal characteris-tics of DMDS. It was found that the biodegradation of DMDS was governed by zero-order reaction -limited macro-kinetics for inlet DMDS concentrations between 10 and 55 ppmv. The overall average zero-order kinetic coeffi-cient for DMDS removal by compost was 0.50 ($\pm$0.1) ppm/sec for both compost mixtures studied. Variations in individual kinetic coefficients were observed due to varying environmental conditions, such as pH and temperature. The kinetic coefficients determined are specific to the system discussed in this work. During high acidity conditions in the filter beds, methyl mercaptan (MM) was observed in the gas samples collected. Appearance of MM was pro-bably due to decreased microbial activity in the lower portions of the biofilter. Considering the neutral pH range required and the presence of methyl mercaptan, it is likely that the microorganisms present in the biofilters used in this research are similar to the T. thioparus (strain E6) species.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E3호
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• pp.153-163
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• 2002

A laboratory- scale dual-column biofilter system was used to study the biofiltration of dimethyl disulfide (DMDS). The gas flow rate and DMDS concentration to the biofilter were varied to study their effect on the remov-al of dimethyl disulfide. Operating parameters such as pH, temperature, and water content were monitored during the biofilter operation and necessary precautions were taken to keep these parameters within the acceptable limits. It was observed that the removal efficiency of DMDS was optimal at neutral pH values. After five month op-eration, the neutralization of the filter beds with sodium carbonate became necessary for the optimum operation of the biofilters. The microbial population already present in the compost mixtures was found to be adequate in treat-ing DMDS. The compost mixtures were found to be similar in terms of biofiltration efficiency of DMDS. However, pressure drops observed in the first column compost mixture (compost/ peat mulch) was extremely high, making this compost economically not feasible. The second mixture (compost/bark) provided pressure drops within accept-able limits. A minimum residence time of 30 seconds at the optimal operating conditions appeared to be adequate for achieving high removal efficiencies (>90%).

• Korean Chemical Engineering Research
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• 제61권2호
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• pp.273-277
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• 2023

The biosorption of methylene blue (MB) from aqueous solution was investigated using dried Rhodotorula glutinis as the biosorbent. The effects of pH, initial dye concentration, biosorbent dosage, and kinetic studies were determined to obtain valuable information for biosorption. Results indicated that most of the adsorbed MB bound within 30 minutes of contact and the MB adsorption capacity increased from 21.1 to 101.8 mg/g with the initial MB concentration increased from 50 to 300 mg/L. Additionally, the MB adsorption capacity gradually increased from pH 4.0 to 9.0, reaching its peak at an initial pH of 9.0. As the biomass load was increased from 0.25 to 4.0 g/L, the MB removal efficiency increased from 14.1 to 84.5%. The Langmuir model provided the best fit throughout the concentration range, and the maximum adsorption capacity (q_max) and Langmuir constant (b) were determined to be 135.14 mg/g and 0.026 l/mg, respectively. Furthermore, the biosorbent process of R. glutinis was found to follow pseudo-second-order kinetics and the calculated q_eq,cal value showed good agreement with the experimental q_eq value. Overall, the biosorption of MB by R. glutinis can be characterized as a monolayer, single site type phenomenon, and the rate-limiting step was determined to be the chemical reaction between the adsorbent and the adsorbate.

• 한국축산시설환경학회지
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• 제21권3호
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• pp.83-92
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• 2015

An attempt to produce more pigs in limited spaces inevitably generalized concentrated feeding operation (CFO). As concentrated pig production practice expanded, concerns on environmental issues grow concurrently. Since odor is the concerned most among those, we attempted to develop means to tackle odor emission from livestock operations. Previously, we excavated few microorganisms from pig manure and, one of them, Bacillus licheniformis was particularly useful to handle odor problem. In this study, we conducted our investigation to further characterize Bacillus licheniformis. Strain identification was conducted using Vitek 2 compact, and the optimal temperature and pH conditions to growth B. licheniformis were searched for by analyzing turbidity on O.D 600 nm. Results of this study can be summarized as these, (1) it was re-verified that the bacterial strain that purified from pig manure was, in fact, Bacillus licheniformis, (2) the bacterial growth was highest when the temperature was kept at $30^{\circ}C$, also (3) growth rate was dependent on media pH as it was high at neutral (6, 7 and 8) but dropped when it was diverged from neutral (4, 5, 9 and 10), and (4) regarding ammonia removal efficiency, B. licheniformis recorded 64% effectiveness after 48 h incubation and reached its highest (80%) at 72 h.