• 대한환경공학회지
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• 제29권4호
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• pp.452-459
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• 2007

부유 및 부착성장 미생물을 이용한 접촉안정형 영양염류처리 하이브리드공정은 질산화 반응조내에 EPS(Expanded Poly-Styrene) 여재를 충진하여 autotrophs와 heterotrophs의 분리성장과 질산화균의 우점화를 도모함으로써 수리학적체류시간 6시간 이내에서도 양호한 처리수질을 얻을 수 있는 공정이다. 본 공정의 운전결과 방류수의 $BOD_5,\;COD_{Mn}$, SS의 평균농도는 5.2 mg/L, 7.3 mg/L, 4.9 mg/L이었으며, T-N 및 T-P농도는 6.8 mg/L 및 0.6 mg/L로서 양호한 처리 결과를 얻을 수 있었다. 또한 본 공법의 평균 제거효율은 $BOD_5,\;COD_{Mn}$, SS의 경우 94.6%, 79.8%, 94.9%이었으며, T-N 및 T-P로서 70.8% 및 76.9%로 나타났다. EPS 여재에 부착된 부착미생물 군집의 16S-rRNA 분석결과 ammonia-oxidizing bacteria로 알려진 Nitrosomonas속, Nitrosoccus속, Gallionella속이 포함된 cluster가 EPS 여재에 부착된 biofilm의 6% 정도인 것으로 조사되었다. 결과적으로 질산화미생물의 우점화를 통해 질산화 반응시간을 단축시킴으로서 6시간 이내의 짧은 수리학적 체류시간에서도 T-N 및 T-P농도를 10 mg/L 및 1.0 mg/L 이하로 처리할 수 있었던 것으로 사료된다.

• 한국환경농학회지
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• 제12권2호
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• pp.112-120
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• 1993

추파 대맥포장에서 기비(基肥)로 시용한 요소(尿素)의 토양중 질산화율(窒酸化率)과 월동기간중 보리의 고사체(枯死體)함유된 질소의 양(量)과 작토층에서 소실(消失)된 질산태질소의 양(量) 및 월동 후 토양에 잔존하고 있는 질소의 양(量)을 추정하고자 실시되었다. 보리 품종 올보리를 공시하고 작물시험장 맥류포장에서 기비 사용량을 0, 40, 80 및 120kg/ha을 요소(尿素)로 시용하였다. 파종은 10월 12일에 하였고 이듬해 3월 17일까지 조사하였으며, 월동기간은 12월 15일부터 3월 17일까지로 하였다. 또한 같은 토양을 이용하여 질산화작용에 미치는 온도의 영향을 밝히기 위하여 5, 10 및 $15^{\circ}C$ 조건에서 4, 8, 16 mg N/100g soil 수준으로 배양(培養)하였다. 1. 토양의 $NH^+\;_4-N$ 및 $NO^-\;_3-N$ 함량의 변화는 요소(尿素) 시용 후 40일경을 기점으로, 40일경까지는 $NH^+\;_4$가, 그리고 그 이후에는 $NO^-\;_3$ 가 각각 가급태(可給態) 질소(窒素)의 주(主)를 이루었다. 2. 토양에 시용된 요소(尿素)의 질산화는 요소(尿素) 시용량이 많을수록, 그리고 온도가 낮을수록 완만하게 진행되었는데, $5{\circ}C$는 $15{\circ}C$에서의 질산화율(窒酸化率) $40{\sim}50%$가 일어났다. 3. 질산화작용(窒酸化作用) 관여하는 ammonia oxidizing bacteria 와 nitrite oxidizing bacteria의 수는 요소(尿素) 용량의 증가에 따라 거의 직선적으로 증가(增加) 하였다. 4. 월동 후 생존한 보리에 함유된 질소량(窒素量)은 기비량(基肥量)의 10% 미만이었고, 작토층에 잔류한 가급태질소(可給態窒素)의 함량은 기비량의 약 $24{\sim}26%$ 이었으며, 월동기간중 보리의 고사체에 함유되어 유기태질소로 소실(消失)된 양(量)은 기비량의 약 50%였고, 질산태질소의 용탈양(溶脫量)은 약 $17{\sim}20%$에 달하였다. 월동기간중 질산태질소의 용탈량은 기비사용량 80 및 120kg/ha에서 각각 ha당 16kg 및 20kg 정도로 추정되었다.

• 미생물학회지
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• 제49권4호
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• pp.321-327
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• 2013

본 연구에서는 암모니아 산화세균과 종속영양세균을 포함한 세균 생물막에 대한 chlorite ($0.66{\pm}0.01mg/L$)의 영향을 monochloramine ($1.77{\pm}0.03mg/L$)의 존재 유무에 따른 조건에서 알아보았다. Chlorite 단독 또는 monochloramine과 함께 적용한 경우에서 공히 생물막과 물 시료에 존재하는 암모니아 산화세균은 검출한계($0.6MPN/cm^2$ and 0.2 MPN/ml)에 근접한 수준으로 감소되는 것으로 나타났지만, chlorite/monochloramine으로 함께 첨가했을 때의 저해효과가 더욱 크게 나타났다. 종속영양세균의 경우 암모니아 산화세균과 달리 chlorite에 의한 저해가 거의 나타나지 않았다. 하지만 chlorite/monochloramine으로 적용한 경우 생물막과 물 시료에서 종속영양세균의 개체 수는 대조군 대비 각각 3.1 log와 3.0 log 감소하는 상당한 저해 효과를 보여주었다. 이러한 결과는 상수관망에 형성된 생물막에 존재하는 질산화 세균과 종속영양세균에 대한 효과적 제어방법중의 하나로 chlorite와 monochloramine 혼합사용의 성공적 가능성을 제시해 준다.

• 상하수도학회지
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• 제20권4호
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• pp.595-604
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• 2006

The growth characteristics of Commercially Developed Nitrifying Bacteria (CDNB) were studied in laboratoryscale. CDNB, a pure, artificially isolated bacterium, was cultivated to produce Cultivated Nitrifying Bacterium Group (CNBG). The average ammonia removal rate of CDNB was 0.0234g $NH_4^+-N/g$ MLSS/hr. CNBG was produced in the batch reactor and Specific Nitrification Rate (SNR) was determined at 0.0107g $NH_4^+-N/g$ MLSS/hr. The SNR of CNBG was lower than the SNR of CDNB because the diverse and multi-cultured microbial growth took place during cultivation. The effect of the temperatures and the mixing ratios of sewage and culture solution on the SNR of CNBG was studied. The SNR of CNBG, 0.0107g $NH_4^+-N/g$ MLSS/hr at $27^{\circ}C$, decreased to 0.0048g $NH_4^+-N/g$ MLSS/hr at $15^{\circ}C$, and temperature coefficient (${\Theta}$) was calculated to be 1.07. With the varied sewage mixing ratios, the SNR of CNBG remained unchanged. Activated sludge reactors maintaining an MLSS of 2,000mg/L at HRT of 4 h were operated under conditions in which dosage of Concentrated CNBG Solution (CCNBGS, 10,000mg MLSS/L) and application method of CNBG were varied. The reactor with 20mL of CCNBGS took shorter time to oxidize $NH_4^+-N$ reaching 1mg/L than the reactor with 5mL of CCNBGS showing that higher dosages were associated with greater mass removal of $NH_4^+-N$. However, the total removal was not great. In terms of different methods of CNBG application, reactor seeded with 20mL of CCNBGS took 3days to reach 1mg/L of effluent ammonia concentration while reactor dosed with 20% (v/v) CNBG implanted media took 2days. Both the control reactor and the reactor dosed with 20% (v/v) media only did not reach 1mg $NH_4^+-N/L$ after operating 18days. The reactor with CNBG implanted media had the highest $NH_4^+-N$ removal rate because of maintaining high concentration of Nitrifying Oxidizing Bacteria (NOM), and is regarded as an appropriate method for the activated sludge process.

• 상하수도학회지
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• 제12권1호
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• pp.52-61
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• 1998

Nitrification and denitrification are important processes in the landfill site as they are deeply related with degradation and stabilization of refuse. Also nitrous oxide ($N_2O$) which is released from both nitrification and denitrification is known as greenhouse gas (GHG). The purpose of this study was to clarify the process by which $N_2O$ produced using $^{15}N$ isotope. Nitrate which was labeled to 10.08% with $^{15}KNO_3$ was used and $N_2O$ was analyzed with GC mass. Results was that even also when $O_2$ of bulk was 15%, $N_2O$ was released from denitrification. And as concentrations of $O_2$ increase, sum of $N_2O$ was released from denitrification. And as concentrations of $O_2$ increase, sum of $N_2O$ and $N_2$ was decreased and ratios of $N_2O$ in the reduced gases were increased. FISH technics also adaped to confirm whether which of nitrifiers existed in the substrates. When NEU was used of which the target was ammonia oxidizing bacteria, nitrifier was not detected at all. So it was confirmed that during the reaction denitrification was dominant process. Total bacteria distributions which were detected by EUB probe explained that as $O_2$ increase the number of bacteria also increase, but between the 10-15% of $O_2$ there was no any differences.

• Journal of Microbiology and Biotechnology
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• 제20권7호
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• pp.1140-1151
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• 2010

Differences in DNA banding patterns, obtained by ribosomal intergenic spacer analysis (RISA), and nitrification were followed in a moving-bed biofilm reactor (MBBR) receiving municipal landfill leachate. Complete nitrification (>99%) to nitrate was obtained in the two-stage MBBR system with an ammonium load of 1.09 g N-$NH_4/m^2{\cdot}d$. Increasing the ammonium load to 2.03 g N-$NH_4/m^2{\cdot}d$or more caused a decline in process efficiency to 70-86%. Moreover, at the highest ammonium load (3.76 g N-$NH_4/m^2{\cdot}d$), nitrite was the predominant product of nitrification. Community succession was evident in both compartments in response to changes in ammonium load. Nonmetric multidimensional scaling (NMDS) supported by similarity analysis (ANOSIM) showed that microbial biofilm communities differed between compartments. The microbial biofilm was composed mainly of ammonia-oxidizing bacteria (AOB), with Nitrosomonas europeae and N. eutropha being most abundant. These results suggest that high ammonium concentrations suit particular AOB strains.

• Fisheries and Aquatic Sciences
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• 제4권1호
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• pp.10-17
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• 2001

One serious problem among the troubles to identify objects in an optical microscopic image is contour background due to non-uniform light source and various transparency of samples. To solve this problem, this paper proposed an elimination method of the contour background and compensation technique as follows. First, Otsu's optimal thresholding method extracts pixels representing background. Second, bilinear interpolation finds non-deterministic background pixels among the sampled pixels. Third, the 2D cubic fitting method composes surface function from pivoted background pixels. Fourth, reconstruction procedure makes a contour image from the surface function. Finally, elimination procedure subtracts the approximated background from the original image. To prove the effectiveness of the proposed algorithm, this algorithm is applied to the yeast Zygosaccharomyces rouxii and ammonia-oxidizing bacteria Acinetobacter sp. Labeling by this proposed method can remove some noise and is more exact than labeling by only Otsu's method. Futhermore, we show that it is more effective for the reduction of noise.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.670-675
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• 2001

This paper is to propose image segmentation method based on chamfer algorithm. First, we get original image from CCD camera and transform it into gray image. Second, we extract maximum gray value of background and reconstruct and eliminate the background using surface fitting method and bilinear interpolation. Third, we subtract the reconstructed background from gray image to remove noises in gray image. Fourth, we transform the subtracted image into binary image using Otsu's optimal thresholding method. Fifth, we use morphological filters such as areaopen, opening, filling filter etc. to remove noises and isolated points. Sixth, we use chamfer distance or Euclidean distance to this filtered image. Finally, we use watershed algorithm and count microorganisms in image by labeling. To prove the effectiveness, we apply the proposed algorithm to one of Ammonia-oxidizing bacteria, Acinetobacter sp. It is shown that both Euclidean algorithm and chamfer algorithm show over-segmentation. But Chamfer algorithm shows less over-segmentation than Euclidean algorithm.

• Geosystem Engineering
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• 제21권5호
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• pp.243-250
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• 2018

This study investigated nitrite ($NO_2{^-}$) accumulation due to FA (Free Ammonia: $NH_3$) inhibition in an anaerobic-aerobic-anoxic (AOA) process reactor to mainly treat wastewater containing 302-610 mg/L of $NH_3/NH_4{^+}-N$. Based on an experimental operation focusing on the nitrification, it was observed that $NO_2{^-}$ was accumulated in the aerobic nitrification zone as pH increased, due to inhibition of $NO_2{^-}$ conversion to $NO_3{^-}$ by FA. This result implied FA inhibition to NOB ($NO_2{^-}$-Oxidizing Bacteria) for converting $NO_2{^-}$ to $NO_3{^-}$. The objective of this study is to develop a feasible monitoring procedure for early detection of the FA inhibition toward $NO_2{^-}$ accumulation and poor nitrification. Thus, in order to rapidly assess FA concentrations, an $NH_3$ probe was utilized to measure $NH_3$ concentrations together with applying a simple model prediction using the measured $NH_4{^+}$ concentrations, the Henry's law constant of $NH_3$ and measured pH. The predictive model $NH_3$ levels were verified by a good correlation (89%) with the corresponding measured data, but the model prediction underestimated FA concentrations at less than 7.4 and a little overestimated at pH above 7.5. Interestingly, accumulated $NO_2{^-}$ levels were roughly correlated with FA levels that were observed at delayed time points. This reflects the detected FA levels can be good indicators of $NO_2{^-}$ levels with some delayed time. $NO_2{^-}$ accumulation started at measured FA concentrations of higher than approximately 3 mg/L and ceased below that FA level.

• 대한환경공학회지
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• 제30권9호
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• pp.939-947
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• 2008

본 연구에서는 PCR-DGGE 기법을 이용하여 DO 농도에 따른 동시 질산화.탈질 반응조 내 미생물 군집 변화 양상을 규명하고자 하였다. DO 농도의 변화에 따른 eubacteria의 군집 변화 해석 실험에서, DO 농도를 2와 1 mg/L로 운전한 반응조 내의 band profile은 거의 유사하게 관찰되었으며 5종의 우점화 미생물(Uncultured Bacterium 3종, Bacillus sp. 1종, Uncultured Bacteroidetes sp. 1종)을 포함한 16종의 미생물을 동정할 수 있었다. 그리고 DO 농도 0.5 mg/L로 운전한 반응조 내의 DGGE 결과 7종의 우점화 미생물(Uncultured Bacterium 5종, Zoogloea sp. 2종)을 포함한 12종의 미생물을 동정할 수 있었으며, DO 농도 0.1 mg/L로 운전한 반응조의 경우 3종의 우점화 미생물(Uncultured Bacterium 1종, Zoogloea sp. 2종)을 포함한 11종의 미생물을 동정할 수 있었다. 반응조 내 DO 농도의 변화에 따른 $\beta$-AOB($\beta$-Ammonia Oxidizing Bacteria)의 군집 변화 해석 실험 결과, 하나의 band를 관찰할 수 있었다. 이 band는 Uncultured Nitrosomonas sp. done DNB Y20와 97%의 유사도를 갖는 것으로 나타났으며 2, 1, 그리고 0.5 mg/L의 DO 농도에서 추출한 sample에서는 선명하게 관측되었으나, 0.1 mg/L DO 농도에서 추출한 sample에서는 선명도가 현저히 감소하였다. 이는 NH$_4{^+}$-N의 질산화 양상과 상관관계가 있음을 보였다. 반응조 내 DO 농도에 따른 탈질 bacteria의 군집 변화 해석실험 결과, 다섯 개의 band(nirS를 함유하는 Uncultured organism 미생물 3종, nirK를 함유하는 Uncultured bacterium 미생물 2종)가 관측되었으며 관측된 band 중 한 band는 DO 농도가 낮아질수록 선명도가 현저히 증가하는 것을 확인할 수 있었다. 이 band에 해당하는 미생물은 86%의 유사도를 가진 Uncultured organism clone eS1 cd1 nirS gene, partial cds로, 본 연구의 탈질 반응에 직접적으로 관여 하는 미생물로 사료된다.