• KSBB Journal
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• v.27 no.1
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• pp.28-32
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• 2012

In this study, the treatment ability of the wastewater containing perchlorate by non-salt tolerant perchlorate reducing bacterial consortium (N-PRBC) was evaluated in a continuous stirred tank bioreactor (CSTR). To obtain the optimal operating condition the bioreactor was operated with the different wastewater empty bed retention time (EBRT). The treatment performance in the bioreactor could be maintained at 100 $mg-ClO_4{^-}L^{-1}$ up to a EBRT of 3 h, and the removal capacity in the CSTR was about 3.3 times higher than that in a batch operation. With a decrease from 9 h to 2 h in a EBRT, the volumetric perchlorate reduction rate was increased from 11.1 $mg-ClO_4{^-}L^{-1}h^{-1}$ to 50.0 $mg-ClO_4{^-}L^{-1}h^{-1}$, and the specific perchlorate reduction rates were increased from 3.01 $mg-ClO_4{^-}g-DCW^{-1}h^{-1}$. In conclusion, the treatment capacities in a CSTR were much better than those obtained in a batch operation.

• Journal of Adhesion and Interface
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• v.24 no.3
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• pp.77-85
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• 2023

In this research, polymeric anionic surfactants having various molecular weights and acid values were synthesized using a continuous stirred tank reactor (CSTR). The CSTR has an advantage of higher production rate and more constant product properties compared to batch and semi-batch reactors. The polymeric surfactants were made using butyl acrylate as a hydrophobic group and acrylic acid as a hydrophilic group. The synthesized polymeric surfactants were ionized with alkali solution and were used as an anionic surfactant. To investigate the properties as a surfactant, the properties of the synthesized surfactant, such as acid value, critical micelle concentration (CMC) and molecular weight, were measured. The results showed that the acid values of the polymeric surfactants were 60 to 380 and a number average molecular weight were 8,000 to 13,000 g/mol. Also, it was found that the CMC was around 0.01 g/ml, which showed similar level values with ordinary surfactant. To prove the performance of the polymeric surfactant, acrylic emulsion PSAs were synthesized using the acquired polymeric surfactant. The results showed that the maximum peel strength of 21.24 N/25mm when acid value was 150 and molecular weight was 8,500 g/mol. The values of peel strength and initial tack of acrylic emulsion PSAs using polymeric surfactant synthesized in this study showed much higher than those of reference PSAs synthesized using ordinary anionic surfactant, SDS (Sodium Dodecyl Sulfate) and SDS/TRX (Triton X-100).

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1075-1080
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• 2009

The partial lipid degradation with the saturation of double-bond at the acidogenesis stage is known to help subsequent methanogenesis during anaerobic digestion. Acidogenic reactions in an anaerobic sequencing batch reactor (ASBR) and a continuously stirred tank reactor (CSTR) were carried out to compare their performances. A mixture of two unsaturated (oleate and linoleate) and two saturated (palmitate and stearate) long-chain fatty acids (LCFAs) was used as a model substrate. Biomass retention in the ASBR contributed to the enhanced performance at hydraulic retention time (HRT) below 15 hr. Biomass retention in the ASBR contributed to the enhanced performance compared to CSTR even at shorter HRT. ASBR would be a proper reactor configuration for the acidogenesis of lipid-containing wastewater.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.330-336
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• 2014

Many industrial processes such as continuous stirred tank reactors(CSTRs), desalination plant, distillation columns, pH neutralization processes and so on exhibit highly nonlinear characteristic and time-varying behavior during operation. The control of such processes has been challenging to control engineers. Hence, a variety of forms of PID controllers and their tuning rules for industrial processes have been developed to guarantee the best performance. In this paper, a scheme that designs the practical PID controller with an anti-windup strategy incorporating with an evolutionary algorithm(EA) is presented for the concentration control of a nonisothermal CSTR. EA is used to tune the parameters of the overall PID control process with anti-windup by minimizing the integral of absolute error(IAE). Simulation works for reference tracking and disturbance rejecting performances and robustness to parameter changes show the feasibility of using the proposed method.

• KSBB Journal
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• v.8 no.3
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• pp.256-265
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• 1993

In this study, it was observed that hydrogen productivity varied with changes of input g1ucose concentration and dilution rate in FBR( Fixed Bed Reactor), and CSTR(Continuous Stirred Tank Reactor). We evaluated and compared reaction rate Parameters and internal external and overall mass transfer resistances of immobilized carrier in both reactors. Apparent $K_m$ decreased with increasing dilution rate in FBR but showed a constant value above $0.4h^{-1}$ of dilution rate in CSTR. The experimental results in FBR showed nearly analogous to those in CSTR, however, the performance of FBR resulted in lower hydrogen productivity and an external effectiveness factor but a higher internal effectiveness factor than in CSTR. The overall effectiveness factor obtained with various input 91ucose concentrations showed similar values in both reactors.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.2
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• pp.104-116
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• 1996

Anaerobic digestion is generally used for the treatment of volatile organic solids such as manure and sludge from waste water treatment plants. However, the reaction rate of anaerobic process is slow, and thus it requires a large reactor volume. To minimize such a disadvantage, physical and chemical pre-treatment is generally considered. Another method to reduce the reactor size is to adopt different reactor system other than CSTR. In this paper, the effects of heat pre-treatment and reactor configurations on the anaerobic treatability of volatile solids was studied. Carrot, kale, primary sludge, and waste activated sludge was chosen as the test materials, and the BMP method was used to evaluate the maximum methane production and first order rate constants from each sample. After the heat treatment at $130^{\circ}C$ for 30min., the measured increase in SCOD per gram VS was up to 394 mg/L for the waste activated sludge. However, the methane production potential per gram VS was increased for only primary and waste activated sludge by 17-23%, remaining the same for carrot and kale. The overall methane production process for the tested solids can be described by first order reactions. The increased in reaction constant after heat pre-treatment was also more significant for the primary and waste activated sludge than that for carrot and kale. therefore, the heat pre-treatment appeared to be effective for the solids with high protein contents rather than for the solids with high carbohydrate contents. Among the four reactor systems studied, CSTR, PFR, CSTR followed by PFR, and PFR with recycle, CSTR followed by PFR appeared to be the best choice considering methane conversion rate and the operational stability.

• Journal of Animal Environmental Science
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• v.5 no.3
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• pp.189-196
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• 1999

Anaerobic digestion is a naturally occuring microbial process involving the decomposition of organic materials such as livestock manure. This study explores the effect of the operating conditions, HRT (Hydraulic Retention Time) and feeding frequency on treatment efficiency for digestion of pig slurry, which has been one of most difficult organic waste for proper treatment in livestock production industry in Korea at the present time. The pilot-scale CSTR of 5 m3 in volume was designed. manufactured, and operated at the temperature of 35$\pm$1$^{\circ}C$. The digester was designed to hydraulically stir for complete mixing and to supply heat from the water bath to maintain mesophilic temperature. The HRT of the digester for Test 1 and Test 2, and Test 3 was set for 17 days and 13 days respectively and pig slurry was fed once a day with 300$\ell$ each for Test 1 and Test 3, while twice with 150$\ell$each for Test 2. Test 2 showed better performance by increase of 4% in VS removal efficiency and 5% in biogas production rate. This is mainly attributed to smaller temperature drop by feeding frequently with half amount, which eventually led to lesser impact on anaerobic mocrobes in the digester. Test 2 maintained optimum pH 7.8 which uplifted the activaton of sulfur-reduction bacteria, alkalinity of around 4,000mg/$\ell$, VA of over 3,000mg/$\ell$ for whole period of experiment. Further research may require to provide the practical operation strategy of anaerobic treatment system for treatment of pig slurry.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.80-84
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• 1994

In order to induce the rapid alcohol fermentation through the increases of the cell density in a continuous alcohol fermentation of naked barley, the single-cultivation with S. cerevisiae IS-019(SCM, ordinary control), mixed-cultivation with Saccharomyces uvarum IS-026 having a flocculent ability and S. cerevisiae IS-019(MCM), and mash recirculation by single-cultivation of S. cerevisiae IS-019(MRM) modes were investigated. The cell mass in the mixed-cultivation mode was about 10% higher than that of ordinary control but the final alcohol yield was slightlyl decreased. When recycled the mash with the flow rate of 7 l/h from V$_{6}$ to V$_{5}$ fermentors under the ordinary control, the cell density was distributed at 140~170$\times $10$^{6}$ cell/ml depending upon the fermentorsorders, higher about 20% than that of the ordinary control. Under these conditions the alcohol productivity of the maximum and the overall was 12.16 g/l$\cdot $h with an alcohol of 7.6% at the V$_{5}$ fermentor and 1.19 g/l$\cdot $h with an alcohol of 8.94%, respectively. For higher cell mass it was more effective to apply the mash recirculation mode with the single-cultivation of S. cerevisiae IS-019 in a pilot scale multi-stage CSTR.

• Proceedings of the Korean Society of Life Science Conference
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• 2002.09a
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• pp.45-45
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• 2002

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.886-889
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• 2017

An active Fault Tolerant Model Predictive Control (FTMPC) using Fuzzy scheduler is developed. Fault tolerant Control (FTC) system stages are broadly classified into two namely Fault Detection and Isolation (FDI) and fault accommodation. Basically, the faults are identified by means of state estimation techniques. Then using the decision based approach it is isolated. This is usually performed using soft computing techniques. Fuzzy Decision Making (FDM) system classifies the faults. After identification and classification of the faults, the model is selected by using the information obtained from FDI. Then this model is fed into FTC in the form of MPC scheme by Takagi-Sugeno Fuzzy scheduler. The Fault tolerance is performed by switching the appropriate model for each identified faults. Thus by incorporating the fuzzy scheduled based FTC it becomes more efficient. The system will be thereafter able to detect the faults, isolate it and also able to accommodate the faults in the sensors and actuators of the Continuous Stirred Tank Reactor (CSTR) process while the conventional MPC does not have the ability to perform it.