• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.96-98
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• 2006

축산폐수는 축사가 대부분 상수원보다 상류지역에 산재하고 있어 이를 효과적으로 관리하기 어려우나, 연속 회분식 반응기(Sequencing Batch Reactor, SBR)는 장치가 간단하고 경제성이 우수하여 축산폐수처리에서 효율적으로 적용될 수 있다. 본 연구에서는 DO(Dissolved Oxygen)과 ORP(Oxidation-Reduction Potential)을 이용하여 지식기반 고장진단 시스템을 제안하였다. 실시간으로 얻어진 ORP, DO값들을 전처리하여, [ORP], [DO]외에 [ORP DO]합성data와 ORP, DO의 특징백터의 합에서 얻어진 fusion data의 총 4개의 data set을 이용하여 각각에 대한 진단과 분류성능을 검토하였다. 이 값을 이용하여 FCM (fuzzy C-mean) 클러스터링 한 후, K-PCA과 LDA로 차원축소시켜 특징백터를 추출하였다. 그리고 Hamming distance로 test data와 특징백터의 거리를 계산하여 각 class를 F1에서 F8까지 분류하였다. 그 결과 데이터를 그대로 이용하는 것 보다 차분데이터형태로 이용하는 것이 우수했으며 그 중 fusion 데이터의 결과가 다른 것들보다 향상된 결과를 보였다. 그리고 K-PCA와 LDA를 결합한 결과가 다른 방법에 비해 우수한 결과를 보였으며 fusion method를 이용한 최고인식율은 98.02%를 나타내었다.

• The Journal of the Korea Contents Association
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• v.6 no.10
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• pp.34-40
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• 2006

In this study, the treatment of organic matters and nutrients like Nitrogen and Phosphorus with sequencing batch reactors (SBR) was conducted. The following conclusions can be summarized from the study. The influent BOD concentration was varied 19.6 to 40.0mg/L and the effluent was 3.0 to 14.8mg/L. The variations of BOD removal efficiency during the experimental period was $47.9{\sim}88.4%$ and the average was 80.8%. The average removal efficiency was stabilized with the passage of time. Also the COD concentration was flowed into as $12.2{\sim}32.0mg/L$ and the effluent concentration was varied 3.3 to 18.6 mg/L, and then the average COD removal efficiency was 57.3%(minimun 19.2% and maximum 78.6%). But fortunately, the COD removal efficiency was also stabilized as 70.2% after 79days. In the case of T-N, the influent concentration range was $7.53{\sim}14.99mg/L$ and the effluent concentration was 6.59mg/L(the average removal efficiency was 40.3%) until the first experiment time 79days. But after normalizing the system, it was 4.44mg/L (the average removal efficiency was 56.4%). Also the influent T-P concentration was varied from 0.77 to 1.91mg/L and the effluent concentration was $0.26{\sim}1.53mg/L$. The removal efficiency was varied from 5.3 to 71.7%. considerably, therefore the average removal efficiency was 42.6%. The reason was concluded that the sludge wasn't discharged for increasing MLSS concentration.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.189-201
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• 1999

범용 열가소성 플라스틱(polyethylene(PE), polypropylene(PP), polystyrene(PS), polyethylene-terephthalate(PET), acrylonitrile-butandiene-styrene(ABS))과 폐윤활유의 동시처리 열분해반응 실험을 수행하였다. 반응실험은 40$m\ell$ 용량의 회분식 미분반응기(microreactor)를 이용한 실험과 1리터 용량의 autoclave를 이용한 실험의 두 가지로 구분하여 행하였다. 전자의 경우는 통계적 실험적계획법(statistical experimental design)의 하나인 회전계획실험(rotatable design experiments)으로서 오각형 실험계획(pentagonal experimental design)에 의거한 반응변수 실험을 수행한 후 반응표면(response surface)을 회기분석법에 의하여 분석함으로써 최대의 오일 수율을 얻을 수 있는 최적 반응조건을 추적, 결정하였다. Autoclave 반응실험의 기본적인 목적은 실제 연속공정에 있어서 열분해 반응기 거동을 모사하기 위한 전초단계로서 충분한 시료의 확보를 통하여 이 때 생성된 연로유의 체계적인 분석(비등점분포특성, 진공증류, 기체분석, 원소분석, 발열량, 비중 등)을 행함으로써 연료유 수율 및 품질을 모사하고자 하였다. 미분반응기 실험에 있어서 주 범용열가소성수지인 PE, PP 그리고 PS는 각각의 최적반응조건하에서 거의 100%에 가깝게 오일로 전환되었지만 응축수지인 PET와 그래프트공중합수지인 ABS의 오일수율은 각기 78% 및 90%로서 상대적으로 낮게 나타났다. Autoclave를 이용한 실험의 경우 혼합플라스틱을 폐유에 대하여 40wt% 혼합하여 열분해하였을 때, 80wt% 오일, 15wt% 코우크, 그리고 나머지 5wt%는 탄화수소기체(C1-C6)로 전환되었다. 진공증류(252$^{\circ}C$,2 torr) 결과, 기/액-분리도는 3으로서 이는 생성오일의 75wt%가 경질연료유(가솔린, 등유, 경유)로 회수 가능하였다.

• KSBB Journal
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• v.11 no.1
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• pp.22-29
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• 1996

Immobilized bioprocess was carried out for continuous production of cyclosporin A (CyA) produced intracellularly as a secondary metabolite by a filamentous fungus, Tolypocladium inflatum. Immobilization procedure for entrapping conidiospores of the producer was significantly simplified by use of a modified immobilization technique. A newly-designed immobilized perfusion reactor system (IPRS) showed good process benefits as demonstrated by the role of the high density immobilized cells as an efficient biomass generator, continuously supplying highly active CyA-producing free cells (1.0g/$\ell$/hr) even at very high dilution rate ($0.1hr^{-1}$). IPRS bioprocess was possible since efficient decantor system developed in our laboratory separated the sloughed-off free cells from the immobilized biomass effectively, thus overcoming wash-out phenomenon frequently encountered in continuous free cell cultures. Furthermore the released-free cells remaining in the bulk solution did not appear to cause substrate mass transfer limitation which was often experienced in suspended mycelial fungal cell fermentations. The primary reason for this was that the suspension broth of the IPRS mainly consisted of roundshaped short mycelial fragments and conidiospores, still remaining Newtonian even at high cell density. In parallel with IPRS bioprocess development, other key factors to be considered necessarily for significant increase in CyA productivity would be strain improvement and medium optimization for the immobilized cells.

• Journal of Environmental Science International
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• v.6 no.6
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• pp.697-709
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• 1997

Sequencing Batch Reactor(SBR) experiments for organics and nutrients removal have been conducted to find an optimum anaerobic/anoxic/aerobic cycling time and evaluate the applicability of oxidation-reduction potential(ORP) as a process control parameter. In this study, a 61 bench-scale plant was used and fed with night-soil wastewater in K city which contained TCODcr : 10, 680 mg/l, TBm : 6, 893 mg/l, $NH_4^+-N$ : 1, 609 mg/l, $PO_4^{3-}-P$ : 602 mg/l on average. The cycling time In SBRs was adjusted at 12 hours and 24 hours, and then certainly included anaerobic, aerobic and inoxic conditions. Also, for each cycling time, we performed 3 series of experiment simultaneously which was set up 10 days, 20 days and 30 days as SRT From the experimental results, the optimum cycling time for biological nutrient removal with nlght-soil wastewater was respctively 3hrs, 5hrs, 3hrs(anaerobic-aerobic-anoxic), Nitrogen removal efficiency was 77.9%, 77.9%, 81.7% for each SRT, respectively. When external carbon source was fed in the anoxic phase, ORP-bending point indicating nitrate break point appeared clearly and nitrogen removal efficiency increased as 96.5%, 97.1%, 98.9%. Phosphate removal efficiency was 59.8%, 64.571, 68.6% for each SRT. Also, we finded the applicability of ORP as a process control parameter in SBRs.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.521-529
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• 1997

In the study, we Investigated the behavior and removal efficiency of organics, nitrogen. phosphorus with operating conditions in SBRs. Substrate used was synthetic wastewater in which the ratio of $COD_{cr}$. : N : P was 100 : 12 : 2. The cycling the in SBRs was adjusted at 6 hours and 8 hours, and then certainly Included anaerobic and aerobic conditions. Also, for each cycling time. we performed 2 series of experiment simultaneously which was set up 10 days and 20 days as SRT. The removal efficiency of $COD_{cr}$. was over 97% in all operating conditions. In the 6 hours cycling time, the removal efficiency of $PO_4^{3-}-P$ reached almost 100% in steady state. And then we could observe a typical phonemena of phosphorus release and uptake, and the removal efficiency of N was 67%, Residual N source was almost TKN and most of the rest remained as $NO_2-N$. Also the difference in both SRTs was not observed practically. In the 8 hours cycling time, dissolution of sludge appeared. and, $PO_4^{3-}-P was not nearly removed but nitrogen was removed up to 75%, And the residual nitrogen was accumulated as $NO_2^--N$.

• Journal of Environmental Science International
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• v.25 no.4
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• pp.525-534
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• 2016

The biological wastewater treatment plant, which uses microbial community to remove organic matter and nutrients in wastewater, is known as its nonlinear behavior and uncertainty to operate. Therefore, operation of the biological wastewater treatment process much depends on observation and knowledge of operators. The manual inspection of human operators is essential to manage the process properly, however, it is impossible to detect a fault promptly so that the process can be exposed to improper condition not securing safe effluent quality. Among various process faults, equipment malfunction is critical to maintain normal operational state. To detect equipment faults automatically, the dynamic time warping was tested using on-line oxidation-reduction potential (ORP) and dissolved oxygen (DO) profiles in a sequencing batch reactor (SBR), which is a type of wastewater treatment process. After one cycle profiles of ORP and DO were measured and stored, they were warped to the template profiles which were prepared already and the distance result, accumulated distance (D) values were calculated. If the D values were increased significantly, some kinds of faults could be detected and an alarm could be sent to the operator. By this way, it seems to be possible to make an early detecting of process faults.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1193-1203
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• 2000

In this study, in order to remove Cd(II) from aqueous solutions, strongly acidic cation exchange resin(SK1B) by Diaion Co. was employed as an adsorbent. Experiments were mainly performed in two parts at room temperature($25{\pm}5^{\circ}C$) : batch tests and adsorption kinetics tests. In batch tests adsorption equilibrium time, pH effects, temperature effects, several adsorption isotherms, and finally desorption tests were examined. In differential bed tests, an optimum flow rate and an overall adsorption rate were obtained. In the batch experiment, adsorption capability increased with pH and became constant above pH 6 and adsorption quantity increased with temperature. Batch experimental data found that Freundlich and Sips adsorption isotherms were more favorable than Langmuir adsorption isotherm over the range of concentration (5~15ppm). The desorbent used in the desorption test was hydrochloric acid solution with different concentrations(0.01~2N). The degree of regeneration increased with concentration of desorbent and decreased slightly with the number of regeneration. In the continuous flow process using a differential bed reactor, the optimum flow rate was $564m{\ell}/min$ above which the film diffusion resistance was minimized. The overall adsorption rate for the removal of Cd(II) by cation exchange resin was found as follows ; $r=1.3785C_{fc}^{1.2421}-2.0907{\times}10^{0.0746C_i}\;q_e^{0.0121C_i-0.0301}$

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.349-354
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• 2009

In this study, a bubbling fluidized-bed reactor was used to study $CO_2$ capture from flue gas using a potassium-based dry sorbent. A dry sorbent, manufactured by the Korea Electric Power Research Institute, consists of 35% of $K_2CO_3$ for $CO_2$ absorption and 65% of supporters for mechanical strength. $H_2O$, a reactant of the carbonation reaction, was supplied in the reactor as a form of saturated water vapor at a given temperature. The experiment of the regeneration reaction was performed by raising up to a given temperature using $N_2$ as a fluidization gas. It was indicated that sorption capacity and regenerability of dry sorbents showed high-efficiency at $1.97\;mol\;H_2O/mol\;CO_2$ and $400^{\circ}C$, respectively. The regenerated sorbent samples were analyzed by TGA to confirm the extent of the reaction. When the regeneration temperature was $150^{\circ}C$, the regenerability of dry sorbents was about 60%, which was capable of applying those sorbents to a two-interconnected fluidized-bed reactor system with continuous solid circulation. The results obtained in this study can be used as basic data for designing and operating a large scale $CO_2$ capture process with two fluidized-bed reactors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.127-133
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• 1999

The purpose of this study was to determine the optimum hydrolysis conditions for the production of enzymatic hydrolysate from tuna boiled extract (TBE) using membrane (molecular weight cut off 10,000Da) reator. The tuna pyloric caeca crude enzyme (TPCCE) was identified as the most suitable enzymes for the hydrolysis of TBE. The optimum hydrolysis conditions of TBE in the batch reactor were $40^{\circ}C$, pH 9 and substrate to TPCCE ratio 50 (w/w). For 6hr under the above conditions, $70\%$ of the total amount of initial TBE was hydrolysed. The optimum hydrolysis conditions of TBE in the membrane reactor were $40^{\circ}C$, pH 9, enzyme 0,1 g/$\ell$, volume 1$\ell$ and substrate to enzyme ratio 100(w/w). The degree of hydrolysis of TBE was above $60\%$ for 3 hr. The TBE hydrolysate were prepared with $5\%$ TBE solution under the optimum hydrolytic conditions in the membrane reactor