• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.3
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• pp.119-126
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• 2001

A process for the production of bioplastics from wastewater with an open microbial culture was developed and evaluated. The process consists of a selection reactor to select bacteria in feast/famine regime and an accumulation reactor to produce PHA using selected bacteria. Polyhydroxyalkanoate(PHAs) accumulating bacteria could be efficiently grown in a sequencing batch reactor(SBR) without any growth limitation. For the high production of PHA limitation such as oxygen and nutrients seemed to be needed. Accumulation experiments were performed to evaluate the level of accumulation of PHA. Limited aeration had no effect, but nutrients limitation showed high accumulation. Bacteria which were selected in the SBR could accumulate PHA till 60% of cellular dry weight in accumulation experiments under nitrogen limitation. PHA accumulation rate decreased with increasing PHA content in the cells. Clearly, PHA accumulation rate has a strong correlation with the PHA content of the cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.322-327
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• 1994

For the improvement of L-lysine productivity, development of the continuous fermentation system by a bioreactor assembly was attempted. Primarily, optimal conditions on the whole cell immobilization of Corynebacterium glutamicum ATCC21514 were studied and 76.2% of immobilization ratio was obtained when the cells were entrapped with 4% k-carrageenan showing 4.0kg gel strength. A bioreactor system was set up using the immobilized cells was applied for the continuous production of L-lysine. The results obtained under the optimum conditions were compared with those of the batchwise fermentation. Experimental results obtained from 14 day continuous fermentation showed 36.7% of sugar conversion to L-lysine while the productivity of L-lysine was disclosed as 4.96mg/ml mg-dry cell weight /hr which is 2.5times and 4.1 times higher than those of the batchwise fermentation by the intact cells and by the immobilized cells, respectively.

• Journal of Energy Engineering
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• v.9 no.2
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• pp.123-129
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• 2000

Mg(OH)$_2$를 흡수제로 이용한 습식탈황에서 페슬러리에 대한 산화반응 특성을 고려하였다. SO3-2 전환율 (MgSO3 폐슬러리의 산화반응 전환율) 과 산소의 물질전달특성을 고찰하기 위해 회분식 및 연속식 실험을 수행하였따. 3리터 용량을 갖는 직사각형모양의 아크릴 반응기에서 공기/슬러리 공급비(20-60) , 수리학적 체류시간(HRT)(1-3hr), SO3-2 유입농도(1000-3000ppm)등의 변화조건에서 실험이 행하여졌다. 실험결과 SO3-2 전환율은 공기공급량과 체류시간에 비례하여 증가하였다. 또한 슬러리 공급에 대한 최적공기공급비 0.02ι/(ι.ppm)에서 MgSO3 폐슬러리는 90%이상 산화되었다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.395-396
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• 2010

Lab scale experiment study was carried out for biological process development on cruise. SBR(Sequence Bath Reactor), MBR(Membrane Bioreactor), and MSBR(Membrane Sequence Bath Reactor) system were investigated for practical application on shipboard sewage treatment. From the results it was suggested that MSBR system might be suitable process for cruise in terms of pollutant removal efficiency, maintenance and special environmental conditions of cruise. Based on Res. MEPC.159(55) the MSBR system was qualified for the required regulations.

• KSBB Journal
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• v.20 no.5 s.94
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• pp.350-354
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• 2005

In order to maximize hydrogen production by Enterobacter cloacae YJ-1, anaerobic hydrogen producing bacteria, the medium composition was optimized. Glucose was better than other carbon sources in hydrogen production and its production was 975.4 mL/L at $2\%$ (w/v) for 48 h. Organic nitrogen sources were more effective than inorganic nitrogen sources and also yeast extract among organic nitrogens was the most effective in hydrogen production. Among metal ions, $Na_2MoO_4$ was most effective, and its production was 1753.3mL/L at $0.04\%$ (w/v). Addition of amino acid was very effective with compare to another components of medium, and cystein was most effective among them. Under the optimum medium obtained in batch culture, semi-batch culture in order to produce continuous hydrogen was run. The highest hydrogen production was earned at $3\%$(w/v) of glucose and the amount was 2215.4 mL/L.

• KSBB Journal
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• v.7 no.2
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• pp.139-143
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• 1992

One of the objectives of this work is to obtain information relevant to the industrial production of alcohol from sugar. The fermentation of alcohol by a strain of saccharomycess cerevisiae ATCC 24858 was studied In a continuous single-stage process with recycle of the cells via tangential flow microfiltration membranes. The experimental results reported in this study pertain to continuous cultures with total cell-recycle by varying the dilution rate (D=0.3, 0.5, and 0.7 $hr^{-1}$) and glucose concentration (50, 100, 150, and 200g/l sugar solution). Productivity using a repeated cell recycle system was found extremely high, 1.e., over 10 to 29 times higher than that of a smile batch system. When a sugar concentration of 200g/1 at dilution rate, 0.7 hr-1 was used, 83.9g/l ethanol was formed with an ethanol yield of 0.42(82% of theoretical) based on sugars utilized.

• Resources Recycling
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• v.15 no.1 s.69
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• pp.46-57
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• 2006

For the development of combustion technology of RDF(refuse derived fuel), combustion characteristics are examined in bubbling fluidized bed, circulating fluidized bed, continuos combustor and batch type combustor. The characteristics of combustion and exhaust gas has been compared and analyzed in many type of combustion facilities, which has been utilized as basic data for the advanced research of specified RDF combustion facility. Stable combustion has been observed in bubbling and circulating fluidized bed from controled operating condition like the proper feeding rate and superficial gas velocity. In circulating fluidized bed, concentration of NOx has been increased with the operating condition by the fuel-NO and oxygen reaction and $SO_2$ can be considered not to be produced in RDF fluidized bed from very low concentration in flue gas. HCl concentration is 36.4 ppm as average value and lower than standard emission value, but the counter plan is needed. Shaped RDF and fluff RDF have been compared in continuos combustor and batch type combustor and shaped RDF shows benefit for the stable heat recovery and gas emission shows similar value and characteristics.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.2
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• pp.79-86
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• 2016

The purpose of this study is to efficiently improve biological sequencing batch reactor (SBR) system of high-concentrated nitrate nitrogen in reverse osmosis (RO) concentrates by total dissolved solids (TDS) regulation. Since a laboratory-scale SBR system had been operated, we had analyzed specific denitrification rate (SDNR) and specific oxygen uptake rate (SOUR) for microbial activity in according to various injection concentration of TDS. As a result, higher injection concentration of TDS decreased SDNR, and delayed denitrification within denitrification process. Moreover, the higher injection concentration of TDS was, the lower microbial activity was during operation of laboratory-scale SBR system. Therefore, the regulation of TDS injection concentration is necessary to improve efficiency of nitrate nitrogen in the biological SBR system, and treatment of calcium ion ($Ca^{2+}$) is also specifically focused to remove nitrate nitrogen. Moreover, analytical data of SDNR and SOUR can be the effective kinetic design parameters to application of biological treatment of RO concentrate by aerobic granular sludge (AGS).

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.1-9
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• 2013

Long term hydrogen production was investigated in an anaerobic sequencing batch reactor (ASBR) using mixed microflora. Glucose (about 8,250 mg/L) was used as a substrate for the ASBR operation under the condition of pH 5.5 and $37^{\circ}C$ with mixing at 150 rpm. The experiment was carried out over a period of 160 days. Hydrogen yield was 0.8mol $H_2/mol$ glucose with F/M ratio 2 at initial operation period. The hydrogen yield reached to maximum 2.6 mol $H_2/mol$ glucose at 80th day operation. However decreased hydrogen yield was observed after 80 days operation and eventually no hydrogen yield. Although well-known hydrogen producer Clostridium sp. was detected in the reactor by PCR-DGGE analysis, changed reactor operation was the major reason of the decreased hydrogen production, such as low F/M ratio of 0.5 and high propionic acid concentration 2,130 mg/L. Consequently the long period operation resulted in MLSS accumulation and then low F/M ration stimulating propionic acid formation which consumes hydrogen produced in the reactor.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.341-352
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• 2017

Butyl acetate is produced from acetic acid and butanol via an esterification reaction in a reactive distillation column. Entrainer can be used for efficient removal of produced water from the reaction region, leading to significant improvement of the column performance. Batch reactive distillation has clear advantages over continuous one in terms of flexibility and adaptability in a small plant. We studied batch and semi-batch reactive distillation processes through process simulation and pilot-scale experiments. We investigated process configuration and type of entrainer for improvement of the column performance and suggested a novel cyclic operation strategy using the semi-batch reactive distillation column. The cyclic strategy was shown to give relatively high production rate and stable operation.