• Journal of Microbiology and Biotechnology
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• 제13권3호
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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.

• 공업화학
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• 제23권1호
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• pp.28-34
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• 2012

본 연구에서는 UASB 반응조를 이용하여 음폐수 탈리액을 원료로 하여 중온소화($35{\pm}0.5^{\circ}C$)와 고온소화($55{\pm}0.5^{\circ}C$)법을 통한 운전을 실시하였다. 20일 동안은 중온소화로 운전을 하면서 5일 간격으로 유출수 재순환 비를 단계적으로 변화시켰다. 고온소화 역시 중온소화와 마찬가지 조건으로 운전을 실시하였다. 실험결과 중온소화 시 유기물제거율은 90% 이상, 메탄수율은 약 66~70%로 나타났다. 고온소화 시 유기물제거율은 80% 이상, 메탄수율은 약 62~68%로 나타났다. 또한, 유출수 반송을 3Q 이상으로 반송하여 운전할 경우 경제적이며 안정적인 운전을 할 수 있었다.

• 한국미생물·생명공학회지
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• 제22권4호
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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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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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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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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.365-369
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• 2000

반응기의 performance를 결정하는 중요한 요소는 methane 생성균의 활성을 측정하는 것이다. Methanogen의 활성을 측정하는 방법으로 SMA가 유일하게 사용되고 있다. 따라서 본 연구에서는 methanogen의 활성을 측정하는 다른 대안으로 CLSM image의 정량 분석 방법을 확립하였다. CLSM의 결과는 약 5시간 안에 얻을 수 있을 뿐만 아니라, 분자 생물학적인 기술을 많이 요하지 않는다. 또한, sludge내부의 상태와 methanogen의 분포정도를 사진으로 볼 수 있는 장점이 있다. 따라서 SMA와 함께 CLSM image 정량 분석은 UASB반응기의 start-up 동안의 methanogen의 활성을 측정하기 위한 유용한 방법으로 제안할 수 있다.

• Journal of Microbiology and Biotechnology
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• 제6권1호
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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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• 제3권1호
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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.