• 한국수자원학회논문집
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• 제46권11호
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• pp.1069-1078
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• 2013

울산시의 주요 생활용수공급댐인 사연댐 상류 수몰지역 내에 국보 285호인 반구대 암각화가 위치하고 있다. 표고 53~57 m에 위치한 암각화 보존을 위한 여러 가지 방안 중, 사연댐 수위를 60 m에서 52 m로 낮추어 물 밖으로 끄집어내는 안이 주로 검토되어 왔다. 댐의 수위를 인위적으로 조절하는 경우 저수량 및 용수공급량 감소와 더불어 부영양화로 인해 수질이 나빠지게 된다. 본 연구에서는 사연댐 수위조절에 따른 수질악화로 댐의 기능상실과 수질변화로 인해 예상되는 여러 가지 문제점을 검토하였다. Vollenweider 모델과 CSTR (Continuous Stirred Tank Reactor) 모델을 이용하여 수위조절시 변화가 예측되는 대표적인 수질지표인 BOD 및 COD 그리고 조류성장의 주 원인이 되는 총인과 총질소의 농도변화를 분석하였다. 그 결과 사연댐의 수위를 60 m에서 52 m로 조절하는 경우, COD의 농도는 약간 낮아지지만 총질소와 총인은 약 130% 이상 농도가 증가되는 것으로 나타났다. 이러한 변화는 심각한 조류문제를 일으킬 수 있으며, 사연댐의 수질관리를 영양염류의 농도를 대상으로 하는 경우 수질이 악화되는 것으로 나타났다.

• KSBB Journal
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• 제9권2호
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• pp.211-223
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• 1994

4l 교반식 생물반응기에서, celite담체에 고정화된 Tolypocladium inflatum 균주 배양시의 산소전달 계수($k_La$)가 같은 세포농도 하에서 액상배양시의 값과 비교할 때, 고정상균주의 높은 비산소흡수율에도 불구하고, 2배 이상 증가되었다. 그 결과 고정상배 양의 경우, 용존산소량이 포화상태의 75%를 초과하는 충분한 산소량이 배양기간 내내 유지될 수 있었으나, 액상배양의 경우에는 용존산소량이 포화상태의 50% 이하까지 감소되었다. 임펠러의 교반속도에 따른 $k_La$의 단순 선형 의존 현상이, 250rpm에서 550rpm 범위에서 고정상배양 및 액상배양 모두에서 관찰되었으며, 그 의존정도는 액상배양의 경우 세포 농도와 함수관계인 반면, 고정상배양의 경우에는 세포농도와 무관하였다. 반면에 두 배양시스템 모두에서, 통기율 변화에 따른 산소전달율은 2.5vvm까지는 함수관계를 보였으나 그 의존도는 임펠러 교반속도의 변화에 따른 영향과 비교할 때 훨씬 미미하였으며, 2.5vvm 이상의 통기율에서는 산소전달현상에 별로 영향을 주지 못했다. CyA 생산 면에서 볼 때, 고정상세포는 형태학 또는 생리학적으로 훌륭한 배양상태를 유지할 수 있어서, 동일조건의 액상배양과 비교해서 약 2배 이상 생산성이 증가되였다. 그러므로 교반식 생물반응기를 이용한 celite-고정상배양법 은 고농도배양이 가능하다는 측면에서 볼 때, CyA 대량생산 산업화를 위한 대체 공정으로서 훌륭한 전망을 제시해 준다.

• 한국수자원학회논문집
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• 제41권3호
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• pp.243-249
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• 2008

본 연구에서는 지표흐름 습지의 수질관리를 위하여 습지 내 오염물질을 적절히 모의할 수 있는 연속교반탱크반응기(CSTR) 모델을 구축하였다. 이 모델은 4차 Runge-Kutta법을 사용하고, 실측치와 계산치의 차이를 최소화 하는 최적화 기법으로 해를 구하며, 미국 EPA 습지 데이터베이스에 수록된 자료중 수질 및 수리자료가 충분하며, 분석이 용이한 하나의 수생대를 갖는 습지를 선택하여, 수질항목중 관심도가 높은 BOD, TSS (Total Suspended Solid)의 모의에 적용하였다. 습지의 체적이 일정할 경우와 체적 및 유량이 일정할 경우 각각에 대해 반응속도상수만을 고려할 경우, 물질흐름양만을 고려할 경우 및 반응속도상수와 물질흐름양 모두를 고려할 경우로 나누어 모의를 실시하였다. 모의 결과 기존의 반응속도상수만을 고려한 경우보다 반응속도상수 및 물질흐름양 모두를 고려하는 것이 실제현상을 잘 나타냈으며, 습지의 TSS 침강속도는 $0.3{\sim}0.4\;m/d$의 값을 나타내는 것으로 파악되었다. 이 모델은 습지의 수질관리에 적절히 활용할 수 있을 것으로 판단된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권5호
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• pp.49-55
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• 2012

A 1.28 L-batch reactor and continuous-flow stirred tank reactor (CFSTR) fed with formate and trichloroethene (TCE) were operated for 120 days and 56 days, respectively, to study the effect of formate as electron donor on anaerobic reductive dechlorination (ARD) of TCE to cis-1,2-dichloroethylene (c-DCE), vinyl chloride (VC), and ethylene (ETH). In batch reactor, injected 60 ${\mu}mol$ TCE was completely degraded in the presence of 20% hydrogen gas ($H_2$) in less than 8 days by anaerobic dechlorination mixed-culture (300 mg-soluble protein), Evanite Culture with ability to completely degrade tetrachloroethene (PCE) and -TCE to ETH under anaerobic conditions. Once the formate was used as electron donor instead of hydrogen gas in batch or chemostat system, the TCE-dechlorination rate decreased and acetate production rate increased. It indicates that the concentration of hydrogen produced in both systems is possibly more close to threshold for homoacetogenesis process. Soluble protein concentration of Evanite culture during the batch test increased from 300 mg to 688 mg for 120 days. Through the protein monitoring, we confirmed an increase of microbial population during the reactor operation. In CFSTR test, TCE was fed continuously at 9.9 ppm (75.38 ${\mu}mol/L$) and the influent formate feed concentration increased stepwise from 1.3 mmol/L to 14.3 mmol/L. Injected TCE was accumulated at 18 days of HRT, but TCE was completely degraded at 36 days of HRT without accumulation of the injected-TCE during the left of experiment period, getting $H_2$ from fermentative hydrogen production of injected formate. Although c-DCE was also accumulated for 23 days after beginning of CFSTR operation, it reached steady-state in the presence of excessive formate. We also evaluated microbial dynamic of the culture at different chemical state in the reactor by DGGE (denaturing gradient gel electrophoresis).

• 한국응용과학기술학회지
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• 제24권4호
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• pp.436-443
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• 2007

Anaerobic reductive dehalogenation of perchloroethene (PCE) was studied with lactate as the electron donor in a continuously stirred tank reactor (CSTR) inoculated with a mixed culture previously shown to dehalogenate vinyl chloride (VC). cis-1,2- dichloroethene (cDCE) was the dominant intermediate at relatively long cell retention times (>56 days) and the electron acceptor to electron donor molar ratio (PCE:lactate) of 1:2. cDCE was transformed to VC completely at the PCE to lactate molar ratio of 1:4, and the final products of PCE dehalogenation were VC (80%) and ethene (20%). VC dehalogenation was inhibited by cDCE dehalogenation. Propionate produced from the fermentation of lactate might be used as electron donor for the dehalogenation. Batch experiments were performed to evaluate the effects of increased hydrogen, VC, and trichloroethene (TCE) on VC dehalogenation which is the rate-limiting step in PCE dehalogenation The addition of TCE increased the VC dehalogenaiton rate more than an increase in the $H_2$ concentration, which suggests that the introduction of TCE induces the production of an enzyme that can comtabolize VC.

• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.652-658
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• 2011

The growth kinetics of Streptomyces noursei NRRL 5126 was investigated under different aeration and agitation combinations in a 5.0 l stirred tank fermenter. Poly-${\varepsilon}$-lysine biosynthesis, cell mass formation, and glycerol utilization rates were affected markedly by both aeration and agitation. An agitation speed of 300 rpm and aeration rate at 2.0 vvm supported better yields of 1,622.81 mg/l with highest specific productivity of 15 mg/l.h. Fermentation kinetics performed under different aeration and agitation conditions showed poly- ${\varepsilon}$-lysine fermentation to be a growth-associated production. A constant DO at 40% in the growth phase and 20% in the production phase increased the poly-${\varepsilon}$-lysine yield as well as cell mass to their maximum values of 1,992.35 mg/l and 20.73 g/l, respectively. The oxygen transfer rate (OTR), oxygen utilization rate (OUR), and specific oxygen uptake rates ($qO_2$) in the fermentation broth increased in the growth phase and remained unchanged in the stationary phase.

• KSBB Journal
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• 제16권5호
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• pp.511-515
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• 2001

TCE및 TCE 분해산물의 높은 독성으로 인하여 TCE 분해 효소 및 세포 불활성화가 일어나서 장기간 안정되게 반응기 운전이 어렵다는 단점을 극복하고, TCE와 성장기질사이의 경쟁적 저해관계로 인한 처리효율 감소도 막기 위하여 TCE분해단계와 세포 및 효소 재활성화 단계를 구분시킨 2단계 CSTR/TBF 시스템을 개발하였다. B. ceapcia G4를 분해 미생물로 사용하였으며, 탄소원인 phenol과 공기 및 배지가연속적으로 공급되는 CSTR에서 효소 및 세포 재활성를 도모하고, TBF에서는 폐가스에 포함된 기사의 TCE를 공기와 함께 공급하여 B. cepcia G4 미생물막에의한 TCE가 분해되도록 구성하였다. 2단계 CSTR/TBF 시스템은 유입 TCE 농도가 15pp $m_{v}$까지도 100% 수준의 처리 효율을 보여주었으며, 고농도의 TCE를 안정적으로 장기간 처리할 수 있었다.다.

• 상하수도학회지
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• 제21권3호
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• pp.315-322
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• 2007

The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a granule of two-phase anaerobic process applied UASB. BMP test was conducted as simple means to monitor relative biodegradability of substrate and to determine methane production of an organic material. The two-phase anaerobic process is consisted of a continuous flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. A stable maximum biogas production rate was 400mL. The methane contents ranged from 73 to 80% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.299-306
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• 2005

Anaerobic fermentation of food waste (FW) and waste activated sludge (WAS) for hydrogen production was performed in CSTR (Continuous Stirred tank reactor) under various HRTs and volumetric mixing ratio (V/V) of two substrates, FW and WAS. The specific hydrogen production potential of FW was higher than that of WAS. However, pH drop in the CSTR for hydrogen production from FW was higher than that from WAS. The maintenance of desired pH during fermentative hydrogen production is regarded as the most important operation parameter for the stable hydrogen production. Therefore, when the potential of hydrogen production from FW and better buffer capacity of WAS, the proper mixture of FW and WAS for fermentative hydrogen production were considered as a useful complementary substrate. The maximum yield of specific hydrogen production, 140 mL/g VSS, was found at HRT of 2 day and the volumetric mixing ratio of 20:80 (WAS : FW). The spatial distribution of hydrogen producing bacteria was observed in anaerobic fermentative reactor using fluorescent in situ hybridization (FISH) method.

• Journal of Biosystems Engineering
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• 제35권1호
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• pp.53-63
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• 2010

The performance of two serial completely stirred tank reactors (CSTRs) for treatment of swine manure (SM) with Chinese cabbage silage (CCS) was studied. The two CSTRs of 41 liters each were connected in series and first reactor was fed swine manure with Chinese cabbage silage in 3:1 proportion by VS basis. The FOS/TAC, methane content (%) and pH were utilized as the parameters for the digester stability control. The FOS/TAC value was found to be effective indicator for instant digester condition. The stability of reactors can be obtained with the FOS/TAC value up to 1.0 with accumulation of FOS value below 10,000 mg/L. Material exchange method was effective in transferring the excess volatile fatty acids (VFA) from the first reactor to the second one and maintaining stability in both the reactors. The biogas yield and the methane yield was 0.55-0.61 and 0.41-0.42 L/g VS fed, respectively, at organic loading rate (OLR) of 2.2-2.6 g VS/L with total HRT of 32 days.