• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1464-1472
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• 2014

The microbial community structures of two continuous stirred tank reactors digesting turkey manure with pine wood shavings as well as chicken and swine manure were investigated. The reactor fed with chicken/swine wastes displayed the highest organic acids concentration (up to 15.2 g/l) and ammonia concentration (up to 3.7 g/l ammonium nitrogen) and generated a higher biogas yield (up to $366ml/g_{VS}$) compared with the reactor supplied with turkey wastes (1.5-1.8 g/l of organic acids and 1.6-1.7 g/l of ammonium levels; biogas yield was up to $195ml/g_{VS}$). The microbial community diversity was assessed using both sequencing and profiling terminal restriction fragment length polymorphisms of 16S rRNA genes. Additionally, methanogens were analyzed using methyl coenzyme M reductase alpha subunit (mcrA) genes. The bacterial community was dominated by members of unclassified Clostridiales with the prevalence of specific clostridial phylotypes in each reactor, indicating the effect of the substrate type on the community structure. Of the methanogenic archaea, methanogens of the genus Methanosarcina were found in high proportions in both reactors with specific methanosarcinas in each reactor, whereas the strict hydrogenotrophic methanogens of Methanoculleus sp. were found at significant levels only in the reactor fed with chicken/swine manure (based on the analyses of 16S rRNA gene). This suggests that among methanogenic archaea, Methanosarcina species which have different metabolic capabilities, including aceticlastic and hydrogenotrophic methanogenesis, were mainly involved in anaerobic digestion of turkey wastes.

• 한국물환경학회지
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• 제20권3호
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• pp.215-222
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• 2004

The sewages produced from small villages, rural community, drinking water reservation area and park which doesn't have sewage piping system can be caused a serious water pollution at the restricted areas. The objective of this research was to suggest an economical and effective sewage treatment method by investigating the removal of the organics, nitrogen, and phosphorus in the multi-soil-layering reactor. Soil, natural zeolite, and iron slag were used as a supporting media of multi-soil-layering in this research. The purpose of natural zeolite addition was to maintain the consistent ammonium exchange capacity by providing a sequential environment, and that of iron slag addition was to remove phosphorus by adsorption. Continuous experiment of lab-scale single-soil-layering (S-1), multi-soil-layering (S-2), and mixed-soil-layering (S-3) methods were studied to compare and optimize three different types of the reactors. The organic removal efficiencies showed more than 90% in all three reactors. While S-1 and S-3 reactors showed about T-N removal of 31%, 45%, respectively, the average T-N removal efficiency of the S-2 reactor represented an 87%. In conclusion, that results suggest that the multi-soil-layering reactor could be effectively utilized as a plant for treatment of small village sewage.

• 한국수소및신에너지학회논문집
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• 제25권1호
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• pp.11-18
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• 2014

This study was conducted to investigate the effect of thermal pre-treatment on bio-hydrogen from food waste. Two continuous reactors operated and VFAs(volatile fatty acids) production and microbial communities were analyzed. The average hydrogen yield was 0.50 and 0.33mol $H_2/mol$ $hexose_{added}$ in thermally treated food added reactor(R1) and control(R2), respectively. Butyrate concentration was similarly 7,500mg/L in both reactors, but two times higher lactate concentration was observed in R2(3,800mg/L). The results of FISH(fluorescence in situ hybridization) showed that the relative microorganism to hydrogen producing bacteria was 78 and 27% in R1 and R2, respectively.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2952-2965
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• 2023

Advanced reactors, such as Small Modular Reactors or existing Nuclear Power Plants, often use Field Programmable Gate Array (FPGA) based controllers in new Instrumentation and Control (I&C) system architectures or as an alternative to existing analog-based I&C systems. Compared to CPU-based Programmable Logic Controllers (PLCs), FPGAs offer better overall performance. However, programming functions on FPGAs can be challenging due to the requirement for a hardware description language that does not explicitly support the operation of real numbers. This study aims to implement the Reactor Trip (RT) functions of the existing analog-based Reactor Protection System (RPS) using FPGAs. The RT equations for Overtemperature delta Temperature and Overpower delta Temperature involve dynamic compensators expressed with the Laplace transform variable, 's', which is not directly supported by FPGAs. To address this issue, the trip equations with the Laplace variable in the continuous-time domain are transformed to the discrete-time domain using the Z-transform. Additionally, a new operation based on a relative value for the equation range is introduced for the handling of real numbers in the RT functions. The proposed approach can be utilized for upgrading the existing analog-based RPS as well as digitalizing control systems in advanced reactor systems.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.159-164
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• 2001

A novel fluidized-bed reactor was designed and installed for bioleaching in a semi-continuous way, by which a process for bioleaching-cyanidation of Guangxi Jinya refractory gold arsenical concentrate was studied. An arsenic extraction rate reaches 82.5% after 4-day batch biooxidation of the concentrate under the optimized condition of pH 2.0, ftrric ion concentration 6.5g/L and pulp concentration 10%. And leaching rate of gold in the following gold cyanidation is over 90%. The parameters of three series fluid-bed reactors exhibit stability during the semi-continuous bioleaching of the concentrate. Arsenic in the concentrate can be got rid of 91% after 6-day leaching. Even after 4 days, 82% of arsenic extraction rate was still obtained. The recovery rates of gold are 92% and 87.5% respectively in cyaniding the above bioleached residues. The results will provide a base for further commercial production of gold development.

• 한국환경과학회지
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• 제9권3호
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• pp.261-266
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• 2000

A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k$_1$ was 0.07~0.17 $\ell$/mgㆍhr and maximum exchange quantity q$_{o}$ was 27.75~31.81 mg/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 mg/$\ell$ nitrate-contained wastewater of 10,000 gallons per day to 2 mg/$\ell$, total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.y.

• 생명과학회지
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• 제24권10호
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• pp.1110-1117
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• 2014

갯벌은 영양염 순환과 오염물질 제거 등 환경적으로 가지는 의미가 크다. 이에 갯벌에서 아밀라아제, 셀룰라아제, 프로테아제, 리파아제를 생성하여 유기물을 분해하는 190균주를 순수분리하고 효소 활성 실험을 통해 그 중 활성이 좋은 균주를 선택하였으며 16S rRNA유전자 분석을 통해 Pseudoalteromonas sp. IC35 (KE804087)로 동정하였다. 또 무기황(S0)을 에너지원으로 하여 최소배지에서 생존 가능한 황산화 세균을 31균주를 순수 분리하고 sulfate ion을 측정하여 황산화능력이 뛰어난 세균을 16S rRNA 분석하여 Halothiobacillus neapolitanus IC_S22 (KE804088)로 동정하였다. 이렇게 분리한 균주들이 환경에서 활성을 가지는 지를 측정하기 위해 유기물 분해에 대해(대조군 M1, 접종군 M2)와 황산화능력에 대해(대조군 M3, 접종군 M4)의 microcosam 반응기를 각각 구축하였다. Pseudoalteromonas sp. IC35를 접종한 M1에서 비접종군인 M2에 비해 유기물 분해 효율이 증가되었으며 microcosm 반응기 내의 생물량도 증가됨을 확인하였다. H. neapolitanus IC_S22을 접종한 M3에서 비접종군인 M4에 비해 환원성 황($S_0$)을 산화하는 능력이 상승되었으며 real time PCR을 이용하여 pilot 내에서 세균의 생물량이 증가함에 따라 초기 sulfate ion의 양도 증가함을 확인하였다. 이번 연구를 통해 대사활성이 우수한 균주를 부가적으로 환경에 접종함으로써 기존 세균 군집에 의한 환경정화 능력을 증가 시키는 것으로 사료된다.

• 대한환경공학회지
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• 제22권6호
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• pp.1001-1009
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• 2000

본 연구는 온도와 pH변화에 따른 처리특성을 S-COD, T-COD, SS, 처리율의 경시변화, 슬러지전환율, SVI 및 유출수 pH의 변화 등을 중심으로 연속포기식과 간헐포기식의 활성슬러지법의 처리특성을 비교하였다. 실험결과 온도보청계수($\theta$)는 연속포기시 1.0~1.061, 간헐포기시는 1.0~1.086으로 나타나 극미하기는 하나 간헐포기시가 온도에 민감한 것으로 나타났으며, 슬러지전환율은 간헐포기시가 연속포기시에 비해 적은 것으로 나타나 보다 경제적이었다. 한편 pH를 변화시킬 경우 양 반응기 모두 산 쪽에서 미미한 악화를 보이나 알칼리 쪽에서는 개선됨을 보여주었고, 전체적으로 처리수의 수질과 유출수의 pH 변화폭 등을 고려할 때 연속포기시에 비해 간헐포기시가 양호하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.18-18
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• 1996

This paper reviews some of the most prominent and promising areas of chemical process control both in relations to batch and continuous processes. These areas include the modeling, optimization, control and monitoring of chemical processes and entire plants. Most of these areas explicitly utilize a model of the process. For this purpose the types of models used are examined in some detail. These types of models are categorized in knowledge-driven and datadriven classes. In the areas of modeling and optimization, attention is paid to batch reactors using the Tendency Modeling approach. These Tendency models consist of data- and knowledge-driven components and are often called Gray or Hybrid models. In the case of continuous processes, emphasis is placed in the closed-loop identification of a state space model and their use in Model Predictive Control nonlinear processes, such as the Fluidized Catalytic Cracking process. The effective monitoring of multivariate process is examined through the use of statistical charts obtained by the use of Principal Component Analysis (PMC). Static and dynamic charts account for the cross and auto-correlation of the substantial number of variables measured on-line. Centralized and de-centralized chart also aim in isolating the source of process disturbances so that they can be eliminated. Even though significant progress has been made during the last decade, the challenges for the next ten years are substantial. Present progress is strongly influenced by the economical benefits industry is deriving from the use of these advanced techniques. Future progress will be further catalyzed from the harmonious collaboration of University and Industrial researchers.

• 한국환경보건학회지
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• 제21권2호
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• pp.12-19
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• 1995

The objectives of this research prograln were to study the ozonation characteristics of phenol contaminated wastewater in the continuous packed column reactor (PCR) and the bubble column reactor (BCR) using ozone that has a strong oxidizing potential, and to provide the fundamentals of ozonizing the phenol contaminated wastewater. Among various influencing factors on phenol decomposition through the oxidation by ozone, phenol/ozone mde ratio was chosen as reaction parameters. Concerning the phenol/ozone mde ratio, as the influent phenol concentration increased from 30 mg/l to 150 mg/l, the phenol removal efficiency decreased from 99% for 30 mg/l to 83.7% for 150 mg/l, in PCR. PCR also showed higher treatment efficiency than BCR by 1% for 30 mg/l and 2.2% for 150 mg/l, respectively. The ozone utilization efficiency of PCR for the phenol concentration 30 mg/l was higher than that of BCR while the efficiency of both reactors was 99.9% for the phenol concentration of 150 mg/l.