• Title, Summary, Keyword: CSTR

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Gas-phase TCE Degradation in a Two-stage CSTR/TBR System Using Methylosinus trichosporium OB3b (Methylosinus trichosporium OB3b를 이용한 2단계 CSTR/살수층 생물막 반응기에서 기상의 trichloroethylene(TCE) 분해)

  • Choe, Yeong-Beom;Lee, Eun-Yeol;Park, Seong-Hun
    • KSBB Journal
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    • v.14 no.4
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    • pp.452-459
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    • 1999
  • A two-stage continuous stirred tank reactor (CSTR)/trickling biofilter reactor (TBR) system was developed for the degradation of gas-phase trichloroethlene (TCE) using Methylosinus trichoporium OB3b. Mrthylosinus trichosporium OB3b was immobilized on activated carbons in TBR and the microbial growth reactor of a CSTR was coupled for the reactivation of the deactivated cells during TCE degradation. The effect of operation variables on TCE conversion and degradation rate were studied. At inlet TCE concentrations ranging from 10 to 80 $\mu$mol/L, TCE degradation rate was increased up to 525 mg TCE/Lㆍday with 75% conversion. The TCE degradation rates were also increased with increse in broth recycle flow rate, gas flow rate and dilution rate. When the temperature of TBR was changed from 3$0^{\circ}C$ to 15$^{\circ}C$, TCE degradation rate and TCE conversion were increased due to the enhanced TCE transfer from gas-phase. The two-stage reactor system was found to be stable and has been operated for more than 270 days.

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Molecular Analysis of the Microorganisms in a Thermophilic CSTR used for Continuous Biohydrogen Production (연속수소생성에 사용되는 고온 CSTR 내의 미생물의 분자적 분석)

  • Oh, You-Kwan;Park, Sung-Hoon;Ahn, Yeong-Hee
    • KSBB Journal
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    • v.20 no.6
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    • pp.431-437
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    • 2005
  • Molecular methods were employed to investigate microorganisms in a thermophilic continuous stirred tank reactor(CSTR) used for continuous $H_2$ production. The reactor was inoculated with heat-treated anaerobic sludge and fed with a glucose-based medium. Denaturing gradient gel electrophoresis showed dynamic changes of bacterial populations in the reactor during 43 days of operation. Gas composition was constant from approximately 14 days but population shift still occurred. Populations affiliated with Fervidobactrium gondwanens and Thermoanaerobacterium thermosaccharolyticum were dominant on 21 and 41 days, respectively. Keeping pH of the medium at 5.0 could suppress methanogenic activity that was detected during initial operation period. $CH_4$ and mcrA detected in the samples obtained from the reactor or inoculum suggested the heat treatment condition employed in this study is not enough to remove methanogens in the inoculum. PCR using primer sets specific to 4 main orders of methanogens suggested that major $H_2$-consuming methanogens in the CSTR belong to the order Methanobacteriales.

CFD Simulation of the Effects of Inlet Flow rate on Hydraulic Behavior in Continuous Stirred-Tank Reactor (CSTR) (CFD 모사 기법을 이용한 유입 유량에 의한 연속 완전혼화 반응조 수리거동 고찰에 관한 연구)

  • Lee, Young Joo;Oh, Jeong Ik;Yoon, Sukmin;Kim, Jong-Oh;Park, No-Suk
    • Journal of Korean Society of Environmental Engineers
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    • v.38 no.1
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    • pp.25-33
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    • 2016
  • This paper describes three-dimensional computational fluid dynamics (CFD) simulation of liquid-liquid flow and transient tracer tests in a full-scale continuous stirred-tank reactor (CSTR) used for drinking water treatment. To evaluate the effects of inlet flow rate on hydrodynamic behavior in the selected CSTR, inlet flow rate was changed from 10% to 100% of the design flow rate. From the results of CFD simulation and analysis, as the inlet flow rate increases, Modal index and ${\beta}$ value are increased. Also, Morrill index shows local minimal points in relation to the inlet flow rate, which are observed at 20% and 40% of the design flow. As inlet flow Increases more than 40%, it is shown that Morrill index re-increases to close to ideal CSTR.

Effects of Reactor Configuration on Upflow Anaerobic Sludge Digestion (반응조 형상이 상향류 혐기성 슬러지 소화에 미치는 영향)

  • Kim, Daeyoung;Kim, Heejun;Park, Kiyoung;Choi, Younggyun;Chung, Taihak
    • Journal of Korean Society of Water and Wastewater
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    • v.17 no.4
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    • pp.550-558
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    • 2003
  • Digestion of primary sludge was conducted to evaluate the effects of reactor configuration using UAD, CUAD, TPAD, and semi-continuos CSTR. Highest VSS reduction and gas production were obtained in CUAD at all HRT. More efficient digestion was accomplished in upflow digesters compared to TPAD and CSTR. Higher thickening of solids in reactor and longer solids retention were main reasons for the enhanced digestion in CUAD and UAD. Performance based on the SRT of CUAD was nearly identical to that of UAD. However, those of TPAD and CSTR were lower than that of CUAD. Particulate and soluble organics in upflow reactors were well adsorbed due to secreted extracellular polymeric substances from the sludge granules. These might result in close proximity of microorganisms and substrates and enhanced hydrolysis. Additionally, diverse anaerobic microorganisms and neutral pH in upflow reactor could induce more activity of hydrolytic enzymes and sludge granules might offer lower thermodynamic energy state. While, excessive mixing in CSTR could break conglomerates of enzymes and substrates into fine particles, which resulted in lowered hydrolysis. Low pH level in acid fermenter of TPAD lowered hydrolysis of the particulate substrates.

A Study on the Effect of the Inclined Structure on the Hydraulic Behavior Index within Sedimentation basin (경사 구조물이 침전지내 수리거동 Index에 미치는 영향)

  • Lim, Seong-Ho;Hwang, Jun-Sik;Park, No-Suk;Kim, Seong-Su;Lim, Kyung-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.23 no.5
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    • pp.517-526
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    • 2009
  • This research has been conducted to investigate the characteristics of hydraulic behavior within the PAC contactor, the rectangular shape sedimentation basin without inclined tube and the other one with inclined tube those are parts of demonstration plants(capacity : $2,000m^3/d$) in Korea Institute of Water and Environment. As results of tracer tests, the flow within PAC contactor was evaluated to divided into plug flow and dead space distinctly, and characteristics of dead space was close to that of CSTR(Complete/continuous Stirred Tank Reactor). Also, considering Reynolds number, Froude number, Morill, Modal, NCSTR Inex and plug flow/mixed flow fraction, in the case of the rectangular shape sedimentation basin without inclined tube, the characteristics of flow pattern was close to CSTR. On the other hand, in the case of the basin with inclined tube, the region of CSTR decreased precisely compared with the case of no-tube. Until now we have recognized that the inclined hydraulic structure just reduces the surface loading rate within a sedimentation basin. Actually besides, the inclined structure have an important effect on the hydraulic behavior within the basin.

Local Control and Remote Optimization for CSTR Wastewater Treatment Systems (CSTR 하.폐수처리장의 국지 제어 및 원격 최적화 시스템)

  • Bae, Hyeon;Seo, Hyun-Yong;Kim, Sung-Shin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.21-25
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    • 2002
  • Activated sludge processes are widely used in biological wastewater treatment processes. The main motivation of this research is to develop an intelligent control strategy for activated sludge process (ASP). ASP is a complex and nonlinear dynamic system because of the characteristic of wastewater, the change in influent rate, weather conditions, and so on. The mathematical model of ASP also includes uncertainties which are ignored or not considered by process engineer or controller designer. The ASP model based on Matlab/Simulink is designed in this paper. The performance of the model is tested by IWA (International Water Association) and COST (European Cooperation in the filed of Scientific and Technical Research) data that include steady-state results during 14 days. In this paper, fuzzy logic control approach is applied to control the DO (dissolved oxygen) concentration. The fuzzy logic controller that includes two inputs and one output can adjust air flowrate. Also, this paper introduces the remote monitoring and control system that is applied for the CSTR (Continuously Stirred Tank Reactor) wastewater treatment system. The CSTR plant has a local control and the remote monitoring system which is contained communication parts which consist of LAN (Local Area Network) network and CDMA (Code Division Multiple Access) wireless module. Remote control and monitoring systems are constructed in the laboratory.

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Effect of Copper on the Suspended Growth Biological Wastewater Treatment (부유 성장식 생물학적 폐수처리에 미치는 구리의 영향)

  • Seo, Jeong-Beom;Hwang, Chang-Min
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.7
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    • pp.479-484
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    • 2013
  • This study was performed to examine the effect of copper on the biodegradability, nitrification, denitrification and oxygen uptake rate (OUR) using batch reactor and continuous flow stirred tank reactor (CSTR) of anaerobic/anoxic/oxic ($A_2/O$). The results of this study can be summarized as follows. In the case of the effect of copper on organic treatment, the bad effect initiated when it was above 4.5 mg/L copper with batch reactor and above 2.0 mg/L copper with CSTR. Concerning the case on nitrification and removal of nitrogen, it showed bad effect when copper was above 4.5 mg/L with batch reactor for nitrification and 1.0 mg/L with CSTR for the removal of nitrogen. The bad effect on the removal of phosphorus began when it was 4.5 mg/L copper with batch reactor and 2 mg/L copper with CSTR. In the case of OUR, it decreased as microbial activity was affected when copper concentration was above 1.5 mg/L in both case of batch reactor and CSTR.

Effect of Zinc on the Suspended Growth Biological Wastewater Treatment (부유 성장식 생물학적 폐수처리에 미치는 아연의 영향)

  • Seo, Jeong-Beom;Hwang, Chang-Min
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.4
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    • pp.228-233
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    • 2015
  • This study was performed to examine the effect of zinc on the biodegradability, nitrification, denitrification and oxygen uptake rate (OUR) using batch reactor and continuous flow stirred tank reactor (CSTR) of anaerobic/anoxic/oxic ($A^2/O$). The results of this study can be summarized as follows. In the case of the effect of zinc on organic treatment, zinc had no effect up to 12 mg/L with batch reactor but biodegradability was lowered when it was above 3.0 mg/L with CSTR. Concerning the case on nitrification and removal of nitrogen, nitrification rate was lowered when zinc was above 6.0 mg/L with batch reactor and removal rate of nitrogen was lowered when zinc was above 3.0 mg/L with CSTR. Removal rate of phosphorus was lowered when it was above 6.0 mg/L zinc with batch reactor and above 3.0 mg/L zinc with CSTR. In the case of OUR, it decreased as microbial activity was affected when zinc concentration was above 3.0 mg/L in CSTR.

Burkholderia cepacia G4를 이용한 기상의 TCE 처리용 2단계 CSTR/TBF 시스템 개발

  • Bae, Hyeon-Cheol;Seol, Eun-Hui;Kim, Hyeon-Suk;Park, Seong-Hun;Lee, Eun-Yeol
    • 한국생물공학회:학술대회논문집
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    • pp.541-544
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    • 2001
  • One of the most promising TCE treatment systems is trickling biofilter (TBF), in which monooxygenase, the corresponding enzyme for initiating growth substrate oxidation, fortuitously transforms TCE via cometabolism. TCE. however. is not easily treated by simple cometabolic biotransformation. This is mainly due to the toxicity of TCE to microbial cell and monooxygenase. In this study, we cleveloped and operated a two-stage CSTR/TBF system for the long-term continuous treatment of TCE. In the two-stage biotransfon11ation system, CSTR with cell recycle from TBR was coupled to the TBR for the reactivation of the cells deactivated during TCE degradation.

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Thermal Decomposition of Copolymers of Butyl methacrylate and Styrene Produced in a CSTR

  • Kim, Duck-Sool;Kim, Nam-Seok;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.4
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    • pp.273-280
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    • 2002
  • Thermal decomposition of the copolymer of butyl methacylate(BMA) with styrene(St) was investigated. The copolymer Was obtained at 80 $^{\circ}C$ in a continuous stirred tank reactor(CSTR) using toluene and benzoyl peroxide(BPO), as solvent and initiator, respectively. The reactor volume was 0.3 liters and residence time was 3 hours. The thermal decomposition followed the second order kinetics for BMA/St copolymer. The activation energies of thermal decompositon were in the ranges of 38 ${\sim}43$ kcal/mol for BMA with St copolymer and a good additivity rule was observed with the composition of copolymer. The thermogravimetric trace curve agreed well with the theoretical calculation.