• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.45-53
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• 1987

The purpose of this research was to study the kinetics of a packed bed aerobic biofilm process. Experiments were carried out by feeding an aerated packed bed reactor with a synthetic wastewater. The reactor packed with glass beads as media had a nominal hydraulic detention time of 5 hours. The flow pattern in the reactor was determined by a tracer test using a NaCl solution to be a completely-mixed type. The results of the research showed that the F/M ratio in the reactor was almost constant since the the biomass increased due to the growth of biofilm as the volumetric organic loading increased. It was also proved theoretically and experimentally that packed bed aerobic biofilm process could be analyzed by the kinetics of completely-mixed activated sludge process with sludge recycle.

• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.202-210
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• 2006

To develop small-scale sewage treatment apparatus for detached house of agricultural village, a small-scale sewage treatment apparatus by natural purification method that consisted of packaged form of aerobic, anoxic and anaerobic bed was constructed. The efficiency of sewage treatment according to the sewage treatment method, sewage loading, and the injection method of sewage were investigated for small-scale sewage treatment apparatus of packaged form of aerobic, anoxic and anaerobic bed. The removal rate of pollutants according to the sewage treatment method for small-scale sewage treatment apparatus was high in the order of aerobic-anoxic-anoxic bed < aerobic-anoxic-anaerobic bed. The optimum filter media in small-scale sewage treatment apparatus was a broken stone. The removal rate of pollutants according to sewage loading in small-scale sewage treatment apparatus was high in the order of $1,200L/m^2{\cdot}day\fallingdotseq900L/m^2{\cdot}day\fallingdotseq600L/m^2{\cdot}day$. The removal rate of pollutants according to injection method of sewage in small-scale sewage treatment apparatus was high in the order of continuous injection $\fallingdotseq$ intermittent injection. When loaded under the optimum conditions, removal rate of BOD, COD, SS, T-N and T-P were 99, 95, 99, 83 and 96%, respectively, through this 3-stepped small-scale treatment apparatus arrayed with the order of aerobic, anoxic and anaerobic bed.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.4
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• pp.597-603
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• 1999

Even though the development of livestock industry in Asia and Australasia has brought the economic growth and thus elevated the living standard in these areas, it has also brought the pollution caused by the increasing amount of animal wastes. Among them, Japan probably is the first country that suffered from the animal waste pollution as early as in 1970s. Nowadays, the animal waste pollution has been a common problem for almost every countries in this region. To solve it, different measures and regulations have been implemented in many countries. In this paper, different methods for animal waste disposal are discussed, including: manure-bed animal housing, composting, anaerobic treatment, odor control, utilization of biogas, aerobic treatment, three-step process, N and P removal, land application, cultivation of algae, anaerobic treatment of dead animals. It is hoped that an animal industry without pollution can be achieved in the future.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.11-20
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• 2001

An anaerobic sludge-aerobic fixed-bed biofilm(packed with ceramic support carrier of 1 inch size) reactor system was built up to treat textile wastewater. The efficiency of reactor system was examined by determining the effects of textile wastewater ratio(from 25% to 100% at HRT 24 h). The influent range of SCOD concentration and color were 1,036~1,357 mg/L, and 1,487~1,853 degree, respectively. When textile wastewater ratio was 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% and the removal efficiency of the whole system were 75.8%. Color removal efficiency by the anaerobic stage were 45.4%(soluble color), and the removal efficiency of the whole system were 70.2%. In the A/A reactor system, the aerobic stage played an important role in removing both color and COD as well as anaerobic stage.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.331-336
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• 1993

A mathematical model for organic removal efficiency was investigated in a fluidized bed biofilm reactor by changing the feed flow rate, the residence time and the recycle flow rate. In batch experiment, organic removal could be assumed as first order and an intrinsic first order rate constant(k1) was found $6.4{\times}^{-6}cm^3/mg{\cdot}sec$ at influent COD range of 3040 - 6620 mg/L. In continuous experiment, at the condition of the influent COD, 3040 mg/L, the superficial upflow velocity, 0.47 cm/sec, the biofilm thickness 336 ${\mu}m$ and the biofilm dry density 0.091 g/mL, the calculated COD removal efficiency from the mathematical model gave 60% which was very close to the observed value of 66 %. As the feed flow rate was increased, the COD removal efficiency was sharply decreased and at constant feed flow rate, the COD removal efficiency was decreased also as the residence time being decreased.

• KSBB Journal
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• v.17 no.1
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• pp.26-32
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• 2002

The aerobic bacterium Xanthomonas campestris was cultivated continuously in a three-phase fluidized bed bioreactor to produce extracellular polysaccharide xanthan, Fluidized particles of 8.0 mm glass beads were used for disintegrating the large air bubbles even at high viscosities to improve the gas-liquid oxygen transfer rate. Xanthin productivity [kg xanthan/kg cell dry mass·h] and molecular weight increased, with dilution rate in the continuous xanthan fermentations. The specific xanthan productivities were not limited by the oxygen transfer rate and were much higher in the continuous cultivations than those predicted by the results of the batch xanthan fermentations.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.181-187
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• 2004

The purpose of this study is to investigate the biofilm reactors capable of doing high efficiency treatment. Vertical fluidized bed biofilm reactor(VFBBR) and spiral fluidized bed biofilm reactor(SFBBR) was used for their performence in biodegradation of artificial sewage. The factors influencing the efficiency of those reactors were compared with difference of physical condition. They had same size but different structure to gain access of its unique characteristics. When recycle solution with flow rate of 22 mL/min and artificial sewage with flow rate of 2~10 mL/min were fed into two reactors in aerobic state, the average $COD_{cr}$, removal rate for biodegradation of SFBBR was greater than VFBBR. After reactor feed sewage was constantly maintained as flow rate of 4 mL/min and the recycle solution were changed to 10~32 mL/min respectively, the average $COD_{cr}$ removal rate of artificial sewage in SFBBR was greater than VFBBR. In this experiment for addition of support media into two reactors SFBBR was 4.1% excellent than VFBBR. Above all, SFBBR excelled VFBBR in boidegradation of organic matter in sewage.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1101-1108
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• 2011

The rise in global energy demand has prompted researches on developing strategies for transforming coal into a cleaner fuel. This requires isolation of microbes with the capability to degrade complex coal into simpler substrates to support methanogenesis in the coal beds. In this study, aerobic bacteria were isolated from an Indian coal bed that can solubilize and utilize coal as the sole source of carbon. The six bacterial isolates capable of growing on coal agar medium were identified on the basis of their 16S rRNA gene sequences, which clustered into two groups; Group I isolates belonged to the genus Rhizobium, whereas Group II isolates were identified as Chelatococcus species. Out of the 4 methods of whole genome fingerprinting (ERIC-PCR, REP-PCR, BOX-PCR, and RAPD), REP-PCR showed maximum differentiation among strains within each group. Only Chelatococcus strains showed the ability to solubilize and utilize coal as the sole source of carbon. On the basis of 16S rRNA gene sequence and the ability to utilize different carbon sources, the Chelatococcus strains showed maximum similarity to C. daeguensis. This is the first report showing occurrence of Rhizobium and Chelatococcus strains in an Indian coal bed, and the ability of Chelatococcus isolates to solubilize and utilize coal as a sole source of carbon for their growth.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1455-1462
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• 2012

The vertical distributions of nitrifying bacteria in aerobic fixed biofilm were investigated to evaluate the relationship between nitrification performance and microbial community at different HRT. Fluorescent in situ hybridization (FISH) and portable ion selective microelectrode system were adopted to analyze microbial communities and ions profiles according to the biofilm depth. Cilia media packed MLE (Modified Ludzack-Ettinger) like reactor composed of anoxic, aerobic I/II was operated with synthetic wastewater having COD 200 mg/L and $NH_4{^+}$-N mg/L at HRT of 6 hrs and 4 hrs. Total biofilm thickness of aerobic I, II reactor at 4 hrs condition was over two times than that of 6 hrs condition due to the sufficient substrate supply at 4 hrs condition (6 hrs; aerobic I 380 ${\mu}m$ and II 400 ${\mu}m$, 4 hrs; aerobic I 830 ${\mu}m$ and II 1040 ${\mu}m$). As deepen the biofilm detection point, the ratio of ammonia oxidizing bacteria (AOB) was decreased while the ratio of nitrite oxidizing bacteria (NOB) was maintained similar distribution at both HRT condition. The ratio of AOB was higher at 4 hrs than 6 hrs condition and $NH_4{^+}$-N removal efficiency was also higher at 4 hrs with 89.2% than 65.4% of 6 hrs. However, the ratio of NOB was decreased when HRT was reduced from 6 hrs to 4 hrs and $NO_2{^-}$-N accumulation was observed at 4 hrs condition. Therefore, it is considered that insufficient HRT condition could supply sufficient substrate and enrichment of AOB in all depth of fixed biofilm but cause decrease of NOB and nitrite accumulation.

• 수도
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• s.50
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• pp.20-25
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• 1989

Water quality of river is greatly influenced by sediments of planktons, suspended solids and organic matters being transported by efflenced. The water quality is also affected by their release at the place of sediments with slow flow of water. This paper deals with the Characteristics of Oxygen consumption of sediments in small river which is greatly vary with time. Some typical samples of sediment were taken from both aerobic and anaerobic condition reserved for several months. and, the samples of sediment were checked on the relative ratio of oxygen consumption by nitrification.