• Environmental Engineering Research
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• 제25권1호
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• pp.1-17
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• 2020

With benefits to the human health, environment, economy, and energy, anaerobic digestion (AD) systems have attracted remarkable attention within the scientific community. Anaerobic digestion system is created from (bio)reactors to perform a series of bi-metabolism steps including hydrolysis/acidogenesis, acetogenesis, and methanogenesis. By considering the physical separation of the digestion steps above, AD systems can be classified into single-stage (all digestion steps in one reactor) and multi-stage (digestion steps in various reactors). Operation of the AD systems does not only depend on the type of digestion system but also relies on the interaction among growth factors (temperature, pH, and nutrients), the type of reactor, and operating parameters (retention time, organic loading rate). However, these interactions were often reviewed inadequately for the single-stage digestion systems. Therefore, this paper aims to provide a comprehensive review of both single-stage and multi-stage systems as well as the influence of the growth factors, operating conditions, and the type of reactor on them. From those points, the advantages, disadvantages, and application range of each system are well understood.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1808-1819
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• 2017

Knowledge on the functional characteristics and temporal variation of anaerobic bacterial populations is important for better understanding of the microbial process of two-stage anaerobic reactors. However, owing to the high diversity of anaerobic bacteria, close attention should be prioritized to the frequently abundant bacteria that were defined as core bacteria and putatively functionally important. In this study, using MiSeq sequencing technology, the core bacterial community of 98 operational taxonomic units (OTUs) was determined in a two-stage upflow blanket filter reactor treating pharmaceutical wastewater. The core bacterial community accounted for 61.66% of the total sequences and accurately predicted the sample location in the principal coordinates analysis scatter plot as the total bacterial OTUs did. The core bacterial community in the first-stage (FS) and second-stage (SS) reactors were generally distinct, in that the FS core bacterial community was indicated to be more related to a higher-level fermentation process, and the SS core bacterial community contained more microbes in syntrophic cooperation with methanogens. Moreover, the different responses of the FS and SS core bacterial communities to the temperature shock and influent disturbance caused by solid contamination were fully investigated. Co-occurring analysis at the Order level implied that Bacteroidales, Selenomonadales, Anaerolineales, Syneristales, and Thermotogales might play key roles in anaerobic digestion due to their high abundance and tight correlation with other microbes. These findings advance our knowledge about the core bacterial community and its temporal variability for future comparative research and improvement of the two-stage anaerobic system operation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.419-422
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• 2004

Textile wastewater from the Pusan Dyeing Industrial Complex (PDIC) was treated utilizing a two-stage continuous system, composed of an upflow anaerobic sludge blanket reactor and an activated Sludge reactor. The effects of color and organic leading rates were studied by varying the hydraulic retention time and influent glucose concentration. The maximum color load to Satisfy the legal discharge limit of color intensity in Korea (400 ADMI, unit of the American Dye Manufacturers Institute) was estimated to be 2,700 $ADMI{\cdot}L^{-1}\;day^{-1}$. This study Indicates that the two-stage anaerobic/aerobic reaction system is potentially useful in the treatment of textile wastewater.

• 한국물환경학회지
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• 제21권3호
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• pp.256-262
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• 2005

The purpose of this study is to investigate the performances of organic removal and methane recovery by using a full scale two-phase anaerobic system. The full scale two-phase anaerobic process was consists of an acidogenic anaerobic baffled reactor (ABR) and a methanognic upflow anaerobic sludge blanket (UASB) reactor. The volumes of acidogenic and methanogenic reactors were designed to $28.3m^3$ and $75.3m^3$. The two-phase anaerobic system represented 60-82% of COD removal efficiency when the influent COD concentration was in the range of 7,150 to 16,270 mg/L after screening (average concentration is 10,280 mg/L). After steady-state, the effluent COD concentration in the methanogenic reactor showed $2,740{\pm}330 mg/L$ by representing average COD removal efficiency was $71.4{\pm}8.1%$ when the operating temperature was in the range of $19-32^{\circ}C$. The effluent SCOD concentration was in the range of 2,000-3,000 mg/L at the steady state while the volatile fatty acid concentration was not detected in the effluent. Meanwhile, the COD removal efficiency in the acidogenic reactor showed less than 5%. The acidogenic reactor played key roles to reduce a shock-loading when periodic shock loading was applied and to acidify influent organics. Due to the high concentration of alkalinity and high pH in the effluent of the methanogenic reactor, over 80% of methane in the biogas was produced consistently. More than 70% of methane was recovered from theoretical methane production of TCOD removed in this research. The produced gas can be directly used as a heat source to increase the reactor temperature.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.14-17
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• 2002

To increase the efficiency of a two-stage anaerobic wastewater digestion system, various polymers were added to the methanogenic reactor as supports. The addition of polyurethane addition (6%, w/v) to the methanogenic reactor facilitated the organic loading rate (2-day Hydraulic Retention Time), higher than that of the conventional methanogenic reactor (6-day HRT). During the operation of the polyurethane-added reactor, a significant decrease in the organic mass in the effluent (COD 5-6 kg/l) was achieved, compared to that of the conventional reactor (COD 15-20 kg/l). The methane gas production rate also improved about 3-fold in the polyurethane-added reactor. More biomass was found to accumulate in the polyurethane-liquid phase (volatile solid, 26-28kg) than in the free-liquid phase (volatile solid, 5- 7 kg/l) after 90 days of operation. A scaled-up experiment with a polyurethane-added 2.5-1 reactor confirmed the previous results, and no adverse effects such as plugging or channeling due to decreased efficiency was observed even after 4 months of operation.

• Environmental Engineering Research
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• 제19권4호
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• pp.355-361
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• 2014

The wastewater treatment with a two-phase expanded granular sludge bed (EGSB) system for anaerobic degradation of acetate, benzoate, terephtalate and p-toluate from purified terephtalic acid (PTA) production was studied. The feasibility and effectiveness of the system was evaluated in terms of organic oxidation by chemical oxygen demand (COD), gas production, bacterial adaptability and stability in the granular sludge. Average removal efficiencies 93.5% and 72.7% were achieved in the EGSB reactors under volumetric loading rates of $1.0-15kg-COD/m^3/day$ and terephtalate and p-toluate of 351-526 mg/L, respectively. Gas production reached total methane production rate of 0.30 L/g-COD under these conditions in the sequential EGSB reactor system. Higher strength influent COD concentration above 4.8 g-COD/L related to field conditions was fed to observe the disturbance of the EGSB reactors.

• 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.

• KSBB Journal
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• 제22권2호
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• pp.97-101
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• 2007

본 연구는 당 연구실에서 구축하고 있는 음식물쓰레기 고부가 자원화zero-emission시스템의 마지막 단계에 해당하는 부분으로써 본 공정의 부산물인 음식물 쓰레기 당화고형분과 박테리아 셀룰로오스배양 후의 여액을 기질 원으로 하여 2상 UASB 반응기를 이용하여 혐기성 소화를 수행하였다. 산 반응조와 메탄 반응조는 각각 35, 40$^{\circ}C$에서 운전하였고 두 반응조의 유기물 부하율은 각각 3g-VS/L${\cdot}$day, 25,000 mg/L로 유지하였다. 공정부산물의 최적 소화조건을 찾기 위하여 F.W + B.C.R, B.C.R, B.C.R + S.S 순으로 단계적으로 주입, 운전한 결과, 최종 메탄 발효액의 pH는 각각 7.13, 7.17, 7.22이었고 COD 제거율은 각각 88, 90, 91%이었으며 메탄 생성율은 각각 0.26, 0.34, $0.32m^3-CH_4/kg-COD_{remove}$이었다. 세번째 단계인 B.C.R + S.S를 기질로 사용한 경우가 음식물 쓰레기만 사용한 경우보다 전환효율이 높았다. 이는 음식물 쓰레기를 바로 혐기성 소화하는 것보다 음식물 쓰레기로부터 고부가가치를 창출하고 그 잔액으로 혐기성 소화를 거치는 방법이 보다 경제적이고 유익함을 알 수 있다. 따라서 당 실험실에서 구축하고 있는 음식물 쓰레기 고부가 자원화 zero-emission 시스템은 음식물 쓰레기에 포함된 에너지를 최대한 회수하고 고부가가치를 창출함에 있어서 가장 이상적인 방법이라고 사료된다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.192-192
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• 2017

Direct-seeding cultivation of rice is increasing in Asia instead of transplanting system, because of its lower cost and operational simplicity. Low-temperature germinability (LTG) and anaerobic germinability (AG) are important characters for breeding of varieties for wide-spread adoption of direct-seeding cultivation in rice. This study was performed to characterize LTG and AG of seven rice varieties and identify varieties with strong germinability on both low-temperature and anaerobic conditions. The mean germination rate and germination vigor of seven varieties were 51.7% and 6.0 under low-temperature condition, respectively. Among these varieties, Cheongcheongjinmi and Hwanggeumnodeul had the highest germination rate of 80%, indicating that Cheongcheongjinmi and Hwanggeumnodeul have a good LTG. In anaerobic conditions, the germination rate and coleoptile length for all varieties were 47.6% and 3.2 cm, respectively. Of them, the highest germination rate and coleoptile length were observed in Subo and Hopum, respectively, suggesting that these two varieties are tolerant to anaerobic during germination stage. Molecular characterization by SDS-PAGE revealed that the protein patterns differed at 50 kDa, 40 kDa, and 22 kDa between low-temperature and anaerobic conditions. Varieties identified as good LTG or AG in this study may be used for developing new direct-seeding rice cultivars through pyramiding these traits in the breeding program.

• 유기물자원화
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• 제11권3호
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• pp.75-86
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• 2003

최근에는 차집관거의 확충, 생활하수의 유입량 증가 및 인근 신규 APT의 분뇨 직유입으로 인해 유입 총고형 물량이 증가됨에 따라 기존 소화조의 용량이 부족할 것으로 예상되고 있다. 본 연구는 기존 소화조 용량부족에 따른 효율감소에 대응하기 위해 미생물제재로써 Bio-dh를 이용하여 소화조내 소화효율 증가(유기물 분해속도 증가)에 따른 최종슬러지 발생량을 감소시키고 가스발생량을 증가시키는데 그 목적이 있다. 실제 하수슬러지를 처리하고 있는 소화조 장치와 동일한 2단혐기성소화조 형태로 설치하였으며, 용량이 $1.3m^3$인 혼합조에 하수슬러지와 미생물제재인 Bio-dh를 주입하였다. 소화방식은 중온성 2단혐기성소화조로서 $35{\pm}1^{\circ}C$를 유지하였고, 1단소화조는 반응조내 미생물과 기질의 원활한 혼합을 위하여 교반기를 부착하였으며, 교반기는 120rpm으로 운전하여 반응조내 완전혼합이 이루어지도록 운전하였다. 2단소화조에서는 소화슬러지와 상등수가 분리되도록 교반을 수행하지 않았다. 소화가스량 측정을 위하여 각 소화조 상부에 가스메타를 설치하였으며, 가스분석을 위하여 상부에 가스포집구를 설치하였다. 교반기 축사이로 발생할 수 있는 발생가스의 누출과 공기의 유입을 막기 위해 water sealing 장치를 교반기 축에 부착시켰다. 실험결과 다음과 같은 결론을 얻을 수 있었다. 1. 미생물제재를 투입하지 않은 경우 소화효율은 평균 48.6%(46.0~50.9%)로 나타난 반면, 미생물제재인 Bio-dh를 투입한 경우 소화효율은 평균 54.2%(52.8~57.3%)로 나타나 미생물제재를 투입한 경우가 미생물제재를 투입하지 않은 경우보다 소화효율이 약 1.12배 정도 높은 것으로 나타났다. 2. 2차소화조 월류수의 수질은 미생물제재 미투입시 $COD_{Mn}$은 평균 1,639mg/L, SS는 평균 4,888mg/L로 나타난 반면, 미생물제재(Bio-dh) 투입시 $COD_{Mn}$은 평균 859mg/L, SS는 평균 2,405mg/L로 나타나 미생물제재 투입시 $COD_{Mn}$은 약 47.6%, SS는 약 50.8% 정도 더 낮게 나타났다.