• 대한치과보철학회:학술대회논문집
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• 1997.11a
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• pp.63-63
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• 1997

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.38-44
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• 2006

Two sulfur-based column reactors inoculated with a bacterial consortium containing autotrophic denitrifiers were operated for 100 and 500 days, respectively and nitrate removal efficiency and the adaptation of microbial communities in the columns were monitored with column depths and time. For better understanding the adaptation phenomenon, molecular techniques including 16S rDNA sequencing and DGGE analysis were employed. Although both columns showed about 99% of nitrate removal efficiency heterotrophic denitrifiers such as Cenibacterium arsenioxidans and Geothrix fermentans were found to a significant portion at the initial stage of the 100-day reactor operation. However, as operation time increased, an autotrophic denitrifier Thiobacillus denitrificans became a dominant bacterial species throughout the column. A similar trend was also observed in the 500-day column. In addition, nitrate removal efficiencies were different with column depths and thus bacterial species with different metabolic activities were found at the corresponding depths. Especially, T. denitrificans was successfully adapted and colonized at the bottom parts of the columns where most nitrate was reduced.

• KSBB Journal
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• v.6 no.4
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• pp.345-350
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• 1991

The purpose of this study is to investigate biomass characteristics and organic removal efficiency by changing superficial upflow velocity and organic loading rate in treating alcoholic distillery wastewater. Since the biomass concentration and the thickness of biofilm are very sensitive to superficial upflow velocity, a high concentration of biomass could be achieved by decreasing superficial upflow velocity that lowered the organic removal efficiency. Therefore, superficial upflow velocity should be controlled as to give optimum conditions and removal efficiency. Generally, activated sludge system shows 70% COD removal efficiency at$1.5kgCOD/m^3{\cdot}day$, but the fluidized-bed biofllm reactor shows 80% COD removal efficiency even at 6kgCOD/$m^2{\cdot}day$.

• KSBB Journal
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• v.21 no.3
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• pp.188-193
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• 2006

A new type of biofilter, a rotating drum biotrickling filter(RDBF), was developed and operated for the removal of styrene from industrial waste gas. The porous polyurethane foam sheet was used as a packing materials for the RDBF and a pure culture of Gram-positive bacterium Brevibacillus sp. SP1 was used as an inoculum. The reactor showed a short start-up period of 18 days, during which uniform biofilms were developed on the packing. During a steady operation at an incoming styrene concentration of $200ppm_v$ and a retention time of 0.5 min, a high and stable removal of styrene over 95% was observed. The maximum elimination capacity was estimated to be $125g/m^3{\cdot}hr$. The outstanding performance was attributed to an efficient gas-liquid mass transfer and the appropriate supply of nutrient solution to the biofilm microorganisms on the packing by the rotation of the drum.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.324-325
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• 2001

총 암모니아성 질소(TAN)은고밀도 양식에서 한계요소로 작용하는 수질인자 중의 하나이다. 생물학적 암모니아 처리공정의 효율적인 설계를 위해서는 생물반응기의 암모니아 제거속도식을 구하여 처리시스템의 최적 용량을 구하여야 한다. 그러나 현재까지 진행된 고정화 미생물을 이용한 암모니아 제거공정에 대한 연구는 고정화 재질의 특성이나 장치의 운전효율에 대한 것으로 속도식에 대한 연구는 부족하다. (중략)

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.88-89
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• 2015

본 연구에서는 선박에서 발생하는 휘발성유기화합물을 처리하기 위하여 친환경적인 대기오염방지설비를 개발하기 위하여 유용미생물 담체를 충전한 바이오필터를 사용하여 VOCs가스를 처리하는 실험실 규모의 실험을 수행하였다. VOCs가스의 온도, pH, 습도, 가스농도와 VOCs가스 제거효율과의 상관관계를 도출하고 이를 바탕으로 바이오필터의 전반적인 VOCs가스 제거효율 및 수명 그리고 안정성 등을 평가하였다. 최적 조건에서의 VOCs 제거 효율은 유입되는 오염가스 농도가 2000ppmv까지 모든 범위에서 90%이상의 제거효율을 나타내는 것으로 보아 이 범위에서 안정적인 운전이 가능한 것으로 평가된다.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.428-432
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• 2006

This study investigated the effect of sulfate source on removal efficiency in electrokinetic bioremediation which needs sulfate to degrade contaminants by an applied microorganism. The representative contaminant and the applied microorganism were phenanthrene and Sphingomonas sp. 3Y, respectively. When magnesium sulfate was used, the magnesium ion combined with hydroxyl ion electrically-generated at cathode to cause the decrease of electrolyte pH, and then the microbial activity was inhibited by that. When ammonium sulfate and disodium sulfate were used to solve the pH control problem, the pH values of electrolyte and soil solution were maintained neutrally, and also the high microbial activity was observed. With the former sulfate source, however, ammonium retarded the phenanthrene degradation, and so the removal efficiency decreased to 12.0% rather than 21.8% with magnesium sulfate. On the other hand, the latter improved the removal efficiency to 27.2%. This difference of removal efficiency would be outstanding for an elongated treatment period.

• KSBB Journal
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• v.17 no.1
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• pp.80-87
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• 2002

Laboratory scale aerobicfanaerobic biofilm reactor was used for simultaneous and stable removal of organics, N and P components to investigate optimum design and operation parameters and to analyze the microbial distribution and consortium structure of nitrification and denitrification bacteria in aerobic and anaerobic biofilm systems. The biofilm reactor was successfully operated for 143 days to show $COD_{cr},\;BOD_5$, SS removal efficiencies of 88, 88, and 97%, respectively. During the experiment period, almost complete nitrification efficiency of 96% was achieved. Denitrification efficiency was about 45% without addition of any external carbon sources. In case of total phosphorus removal, 74% of the inlet phosphorus was removed. Fluorescence in situ hybridization (FISH) results showed that most of the ammonia oxidizing bacteria in the aerobic nitrification zone was found to be Nitrosomonas species while Nitrospira was the representative nitrite oxidizing bacteria. For the denitrification, Rhodobacter, Rhodovulum, Roseebacter and Paracouus were the dominant denitrification bacteria which was 10 to 20% of the total bacteria in numbers.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.764-769
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• 2006

In the electrokinetic(EK) process, oxygen production by electrolysis was proportional to current density. The dissolved oxygen (DO) concentration in anode tank and bioreactor increased with the circulation rate of electrolyte. The bacterial population in bioreactor rapidly increased by the supplement of current, but the DO concentration deceased by the increased bacterial oxygen consumption. From the results of EK bioremediation for pentadecane-contaminated soil, the bacterial population and removal efficiency at 1.88 $mA/cm^2$ were lower than those at 0.63 $mA/cm^2$. This is because the high oxygen production rate largely increased the production rate of organic acids, which reduced the electrolyte pH and bacterial activity. At 0.63 $mA/cm^2$, the highest bacterial population and removal efficiency could be obtained due to the appropriate oxygen production and small decrease in pH.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.939-947
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• 2000

Enhanced biological phosphorus removal (EBPR) was performed in an anaerobic/aerobic sequencing batch reactor (SBR). Influent was a synthetic wastewater based on acetate as a carbon source. The sludge age and hydraulic retention time were kept at 10 days and 16 hrs, respectively, Phosphate release during the anaerobic period and phosphate uptake in aerobic period were increased gradually with time. and after about 200 days, steady-state operation could be achieved with complete removal of influent phosphate. Number distribution of microbial community in the sludge performing EBPR was investigated during the steady state operation. 17 rRNA targeted oligonucleotide probes were designed and slot hybridization technique was used to determine the number distribution of each microorganism. In the acetate fed SBR, rRNA belonging to the beta subclass of proteobacteria was the most dominant in total rRNA and rRNA matching to CTE probe was the second, rRNAs of Acinetobacter, Aeromonas and Pseudomonas, which are usually thought as phosphorus accumulating organisms in EBPR processes, constituted less than 10% of total rRNA. From this community analysis, it was inferred that microorganisms belong to the beta subclass of proteobacteia (BET) and CTE such as Rhodocyclus group were important in biological phosphorus removal. Therefore, the role of Acinetobacter, Aeromonas and Pseudomonas in the EBPR might have been overestimated.