• Proceedings of the KSME Conference
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• 2000.04b
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• pp.13-18
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• 2000

The objective of the Present study is to investigate the performance of electronic scale mitigation unit(ESMU), which reduces the amount of scale in a heat exchanger. A plate heat exchanger with 20 thermal plates is used for the tests. In order to accelerate the rate of fouling in a laboratory test artificial hard water of 2000 ppm(as $CaCO_3$) is recirculated at a flow rate 5L/min throughout the tests. The overall heat trans(or coefficients and fouling factors are examined. Results show that the ESMU technology can significantly reduce the scale deposits.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.787-791
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• 2005

Mutation and its pilot-scale fermentation were conducted for the production of teicoplanin from Actinoplanes teichomyceticus. The fermentation medium was optimized by replacement and Plackett-Burman experimental design. A maximum production of 1,500 mg/l teicoplanin was obtained by pilot-scale fermentation in an optimized medium containing (g/l): 30 g maltodextrin, 5 g glucose, 5 g yeast extract, 5 g soybean meal, 0.5 g $MgSO_4{\cdot}7H_2O$, 0.1 g NaCl, 0.1 g $CaCl_2{\cdot}2H_2O$, and 50 g Diaion HP-20. The production of teicoplanin was improved 3-fold from the parental strain by mutation, media optimization, and fermentation, and laboratory-scale fermentation was successfully demonstrated in a pilot-scale fermenter for the industrial production of teicoplanin.

• Journal of the Korean institute of surface engineering
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• v.26 no.5
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• pp.255-262
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• 1993

Major parameters determining the extent of Ca utilization were investigated for their calcination/sulfation behavior of limestone in the AFBC(Atmospheric Fluidized Bed Combustion) environments. Three different particle sizes of Fredonia limestone were investigated in the lab-scale tubular reactor. The results of the calcination codnversion of limestone imply that thesd decomposition rate of CaCO3 into CaO is dependent on the amount of heat which limestone absorbed. Hg porosimeter measurement of calcined limestone illustrated that surface area and pore volume are increased with decreasing particle size. Raw Fredonia limestone and sequentially as well as simultaneously calcined/sulfated limestones were also examined using SEM. The SEM Studied showed that the surface of the calcined limestone particles is more diffusive nature than that of the parent calcite. However, the sulfur distribution pattern of simultaneously-treated particles and that of the se-quentially-treated one shows no difference.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.4
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• pp.469-477
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• 2021

Safe storage of spent nuclear fuel in deep underground repositories necessitates an understanding of the long-term alteration of metal canisters and buffer materials. A small-scale laboratory alteration test was performed on metal (Cu or Fe) chips embedded in compacted bentonite blocks placed in anaerobic water for 1 year. Lactate, sulfate, and bacteria were separately added to the water to promote biochemical reactions in the system. The bentonite blocks immersed in the water were dismantled after 1 year, showing that their alteration was insignificant. However, the Cu chip exhibited some microscopic etch pits on its surface, wherein a slight sulfur component was detected. Overall, the Fe chip was more corroded than the Cu chip under the same conditions. The secondary phase of the Fe chip was locally found as carbonate materials, such as siderite (FeCO₃) and calcite ((Ca, Fe)CO₃). These secondary products can imply that the local carbonate occurrence on the Fe chip may be initiated and developed by an evolution (alteration) of bentonite and a diffusive provision of biogenic CO₂ gas. These laboratory scale results suggest that the actual long-term alteration of metal canisters/bentonite blocks in the engineered barrier could be possible by microbial activities.

• Mycobiology
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• v.43 no.4
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• pp.467-474
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• 2015

Development of efficient substrate formulas to improve yield and shorten production time is one of the prerequisites for commercial cultivation of edible mushrooms. In this study, fifteen substrate formulas consisting of varying ratios of palm press fibre (PPF), mahogany sawdust (MS), Gmelina sawdust, wheat bran (WB), and fixed proportions of 1% calcium carbonate ($CaCO_3$) and 1% sucrose were assessed for efficient Lentinus squarrosulus production. Proximate compositions of mushrooms produced on the different substrate formulas were also analysed and compared. Substrate formulations containing 85% PPF, 13% WB, 1% $CaCO_3$, and 1% sucrose were found to produce the highest carpophore yield, biological efficiency and size (206.5 g/kg, 61.96%, and 7.26 g, respectively). Days to production (first harvest) tended to increase with an increase in the amount of WB in the substrate formulas, except for PPF based formulas. The addition of WB in amounts equivalent to 8~18% in substrate formulas containing 80~90% PPF resulted in a decrease in the time to first harvest by an average of 17.7 days compared to 80~90% MS with similar treatment. Nutritional content of mushrooms was affected by the different substrate formulas. Protein content was high for mushrooms produced on formulas containing PPF as the basal substrate. Thus, formulas comprising PPF, WB, $CaCO_3$, and sucrose at 85% : 13% : 1% : 1%) respectively could be explored as starter basal ingredients for efficient large scale production of L. squarrosulus.

• Korean Journal of Environmental Agriculture
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• v.30 no.1
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• pp.31-36
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• 2011

BACKGROUND: Disposal of slurry animal manure produced by an anaerobic slurry-type barn method is not easy since the animal slurry contain high moisture content which makes solid-liquid separation a difficult process. However, recently, the interest about anaerobic digestion process as an environment-friendly waste disposal method has gained a wide interest because it can treat highly organic matter contained by the piggery slurry, decrease the odor after treatment, and enable the effective recovery of the methane gas which is a valuable energy resource. The objectives of this study were to identify the solubilization characteristics and to improve the anaerobic digestion efficiency of piggery slurry through full-scale anaerobic digestion experiments. METHODS AND RESULTS: In a full-scale continuous anaerobic digestion operation, the adaptability of single anaerobic digestion and its digestion efficiency were also evaluated in the farm field. The actual pH range and alkalinity concentration of piggery slurry used during the operation were comparatively higher than the concentrations of pH and alkalinity in the digestion tank which were stable at 7.5~8.0, 4,008 mg/L (as$CaCO_3$), respectively. The removal efficiency of organic matter (TCOD) by anaerobic digestion was 75~90% and methane gas production amount was at 0.33 L/L/day, a little higher than that of ordinary animal manure. CONCLUSION(s): Our findings showed higher recovery of highly purified methane and greater efficiency of anaerobic tank digestion since its methane gas content was at 65~70%.

• Journal of Soil and Groundwater Environment
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• v.18 no.7
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• pp.73-80
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• 2013

Fine suspended solids from coal mine drainage were treated in the treating plant, using two different pilot-scale inclined clarifiers: radial and lamella types. Suspended solids in the mine drainage were monitored along with other geochemical factors, and metal contents. Fe and Mn are the main chemical components in the drainage, which exist predominantly as total metal forms, whereas dissolved portion is negligible. The raw mine drainage is subject to physical and chemical treatment using $CaCO_3$ and NaOH, therefore the suspended solids are thought to be composed of Fe and Mn precipitates, possibly $Fe(OH)_3$, along with carbonate precipitates. The elemental composition of precipitates are confirmed by SEM-EDS analysis. As nearly all the dissolved ions were precipitated in the primary process by $CaCO_3$, no further aeration or prolonged oxygenation are of necessity in this plant. Adoption of inclined clarifier proved to be effective in treating fine suspended solids in the current plant. Successful application of the inclined clarifier will also be beneficial to improve the current treating process by excluding the current application of chemical agent in the first stage. The final effluents from the pilot plant meet the national standards and the low dissolved Fe and Mn contents are expected not to cause secondary precipitation after discharge.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1066-1071
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• 2017

Recently high voltage impulse (HVI) technique has been extensively studied for desalting processes to control the $CaCO_3$ scale formation in industrial water practices such as power plant, boiler, and heat exchange operations. Investigation of the operational parameters for the HVI is important, however, those had not been reported yet. In this study, the effect of initial feed volume and contact time on reduction of calcium ion concentration by the HVI technique was investigated. Initial feed volumes of artificial hard water which contained 100 mg/L of $Ca^{2+}$, were set to 1, 2, and 3 L respectively. After 24hr of HVI contact with 12kV, $Ca^{2+}$ ion was reduced to 50, 29 and 19 % of their initial concentration, indicating that calcium removal increased as initial feed volume decreased. This implies the applied HVI pulse energy per unit mass of calcium is important parameter determining overall desalting efficiency. A series of extended operations of HVI up to 30 days verified the long term stability of the HVI system. The calcium ion declined to 40 mg/L after 2~3 days, and further reduction of calcium was not achieved, indicating that optimum operation time could be 2~3 days under these experimental conditions. Consequently, it was confirmed that the important operational parameter of HVI technique is initial feed volume and contact time as well as the applied voltage that was already proven in the previous study.

• Economic and Environmental Geology
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• v.41 no.2
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• pp.201-210
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• 2008

The mixing treatment process using lime (CaO) and limestone ($CaCO_3$) as the immobilization amendments was applied for heavy metal contaminated filmland soils around Goro abandoned Zn-mine, Korea in the batch and pilot scale continuous column experiments. For the batch experiments, with the addition of 0.5 wt.% commercialized lime or limestone, leaching concentrations of As, Cd, Pb, and Zn from the contaminated filmland soil decreased by 70, 77, 94, and 95 %, respectively, compared to those without amendments. For the continuous pilot scale column experiments, the acryl column (30 cm in length and 20 cm in diameter) was designed and granulated lime and limestone were used. From the results of column experiments, with only 2 wt.% of granulated lime, As, Cd, and Zn leaching concentrations decreased by 63%, 97%, and 98%, respectively. With 2 wt.% of granulated limestone, As leaching concentration reduced from 135.6 to 30.2 ${\mu}g/L$ within 5 months and maintained mostly below 10 ${\mu}g/L$, representing that more than 46% diminution of leaching concentration compared to that without the amendment mixing. For Cd and Zn, their leaching concentrations with only 2 wt.% of limestone mixing decreased by 97%, respectively compared to that without amendment mixing, suggesting that the capability of limestone to immobilize heavy metals in the filmland soil was outstanding and similar to that of lime. From the column experiments, it was investigated that if the efficiency of limestone to immobilize heavy metals from the soil was similar to that of lime, the limestone could be more available to immobilize heavy metals from the soil than lime because of low pH increase and thus less harmful side effect.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.45-51
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• 2012

The calcium hydroxide$(Ca(OH)_2)$ which is the cement hydrate flowed into the tunnel by groundwater is reacted with microorganism in the soil, carbon dioxide$(CO_2)$ and the vehicle's exhaust gas$(SO_3)$. So its by-products are precipitated at the drainage pipe and these cause the drainage clogging. By this phenomenon, Degradation of water flow at the drainage system of the tunnel occurred and also pore water pressure is increased. Hence the acceleration of seepage and degradation of lining is occurred. The purpose of this study is to evaluate the field applicability of the Quantum Stick and Magnetic treatment in prevention of scale deposits at the Namsan ${\bigcirc}{\bigcirc}$ tunnel and the Zone ${\bigcirc}{\bigcirc}{\bigcirc}$ of subway. These technologies were installed into drainpipes with their performance monitored through occasional site visits. SEM and XRD were also performed on scale collected from these drainpipes. As a result, in case which factor technology is applied, scale creation is remarkably decreased and especially Quantum Stick treatment performing better than Magnetic treatment. Therefore, additional application of Quantum Stick or Magnetic treatment to the existing drainage is expected to decrease the drainage clogging of the drainage.