• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.378-384
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• 2003

Mesophilically-grown granular sludge seeded in thermophilic UASB reactor was monitored to better understand the start-up process of the reactor. The reactor was fed with a synthetic wastewater containing glucose. As COD loading rate increased stepwise, methane production rate increased. Maximum values of COD removal efficiency (95%) and methane production rate (5.3 l/day) were achieved by approximately day-80 and remained constant afterward. However, physicochemical and microbial properties of granules kept changing even after day-80. Specific methanogenic activity (SMA) was initially negligible, and increased continuously until day-153 and remained constant afterward, showing the maximum value of $1.51{\pm}0.13\;g\;CH_4-COD/g$ VSS/day. Deteriorated settling ability of granules recovered the initial value by day-98 and was maintained afterward, as determined by sludge volume index. Initially reduced granule size increased until day-126, reaching a plateau of 1.1 mm. Combined use of fluorescence in situ hybridization and confocal laser scanning microscopy (CLSM) allowed to localize families of Methanosaetaceae and Merhanosarcinaceae in granules with time Quantitative analyses of CLSM images of granule sections showed abundance patterns of the methanogens and numerical dominance of Methanosaeta spp. throughout the start-up period. The trend of SMA agreed well with abundance patterns of the methanogens.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.28-34
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• 2012

In this study, we operated a UASB (upflow anaerobic sludge blanket) reactor by using foodwaste leachate as a raw material with the method of Mesophilic Digestion ($35{\pm}0.5^{\circ}C$) and Thermophilic Digestion ($55{\pm}0.5^{\circ}C$). During 20 days of operating time with the Mesophilic Digestion, the recirculation ratio of effluent was stepwisely changed in every five days. Thermophilic Digestion was carried out at the same condition for Mesophilic Digestion. Results showed that the organic removal efficiency of Mesophilic Digestion was over 90% and the yield of methane production was from 66 up to 70%. The organic removal efficiency of Thermophilic Digestion was over 80% and the yield of methane production was between 62 to 68%. Also, when UASB reactor was operating to over the 3Q effluent recirculation, the experiment could be carried out economically and stably.

• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.407-414
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• 1994

Anaerobic fermentative bacteria were isolated from the acidogenic reactor of a labora- tory scale 2-stage anaerobic digestor. The isolate 1-6 was selected for its ablity to produce more fatty acids from distillery wastewater than others, and was identified as a strain of Clostridium. The isolate Clostridium sp. 1-6 is a thermophilic bacterium growing at 55$\circ$c , and grew best at pH 5.5. An acidogenic reactor using immobilized cells of the isolate Clostridium sp. 1-6 removed about 15% of COD from distillery wastwater as hydrogen, producing about 50 mM butyrate and about 10 mM acetate, when the reactor was operated at the hydraulic retention time(HRT) of 0.8 hr. It is proposed that this system can be used to convert the distillery wastewater to hydrogen and butyrate. More than 90% of COD was removed from the wastewater by anaerobic digestion using a 2-stage digestor consisting of a UASB methanogenic reactor and an acidogenic reactor of the immobilized cells of isolate Clostridium sp. 1-6.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.508-511
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• 2000

In situ hybridization with fluorescent oligonucleotides(FISH) was used to detect and localize microorganisms in the granules of lab-scale upflow anaerobic sludge blanket(UASB) reactors. An UASB reactor was seeded with mesophilically-grown($35^{\circ}\;C$) granular sludge, and thermophilically($55^{\circ}\;C$) operated by feeding with a synthetic wastewater. Sections of the granules were hybridized with 16S rRNA-targeted oligonucleotide probes for Eubacteria, Archaeabacteria, and specific phylogenetic groups of methanogens. FISH clearly showed the layed structure of thermophilic granules, which was consisted of outer bacterial cells and inner archaeal cells. Methanoseata-, Methanosarcina-like cells were also found to be localized inside the granules. These results demonstrated FISH was useful in studying the spatial organizations of methanogens and in situ morphologies and metabolic functions in thermophilic granular sludges.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.365-369
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• 2000

Methanogenic activity of granular sludge was monitored by specific methanogenic activity (SMA) assay and confocal laser scanning microscopy (CLSM) during start-up of a thermophilic UASB reactor. Autofluorescence by CLSM could visualize the methanogenic bacterial population inside sludge granules and its intensity was proportional to SMA. Considering the complex procedures of SMA measurement, fluorescence quantification by CLSM can be suggested as a routine technique measuring methanogenic activity in UASB granules.

• Journal of Microbiology and Biotechnology
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• v.6 no.1
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• pp.30-35
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• 1996

Distillery wastewater was used in a thermophilic laboratory-scale two stage anaerobic digester to test the effects of the redox potential of the first acidogenic reactor on the performance of the system. The digester consisted of first a acidogenic reactor and the an upflow anaerobic sludge blanket (UASB) reactor. The digestor was operated at a hydraulic retention time (HRT) of 48 h. Under these conditions, about 90% of the chemical oxygen demand as measured by the chromate method ($COD_{cr}$) was removed with a gas production yield of 0.4 l/g-COD removed. The redox potential of the acidogenic reactor was increased when the reactor was purged with nitrogen gas or agitation speed was increased. The increase in reduction potential was accompanied by an increase in acetate production and a decrease in butyrate formation. A similar trend was observed when a small amount of air was introduced into the acidogenic reactor. It is believed that the hydrogen partial pressure in the acidogenic reactor was decreased by the above mentioned treatments. The possible failure of anaerobic digestion processes due to over-loading could be avoided by the above mentioned treatments.

• Membrane and Water Treatment
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• v.3 no.1
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• pp.1-23
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• 2012

The coupling of anaerobic biological process and membrane separation could provide excellent suspended solids removal and better biomass retention for wastewater treatment. This coupling improves the biological treatment process while allowing for the recovery of energy through biogas. This review gives a basic description of the anaerobic wastewater treatment process, summarizes the state of the art of anaerobic membrane bioreactors (AnMBRs), and describes the current research trends and needs for the development of AnMBRs. The research interest on AnMBR has grown over the conventional anaerobic processes such as upflow anaerobic sludge blanket (UASB). Studies on AnMBRs have developed different reactor configurations to enhance performances. The AnMBR performances have achieved comparable status to other high rate anaerobic reactors. AnMBR is highly suitable for application with thermophilic anaerobic process to enhance performances. Studies indicate that the applications of AnMBR are not only limited to the high strength industrial wastewater treatment, but also for the municipal wastewater treatment. In recent years, there is a significant progress in the membrane fouling studies, which is a major concern in AnMBR application.