• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.17-22
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• 2006

This study is about backwash condition and membrane fouling at continuous coagulation/ultrafiltration process in water treatment. The capacity of pilot plant was $0.06m^3/d$. The result of the test, Backwash cycle time and duration time had a significant effect on the efficiency of system and backwash. Backwash duration time was determined to be fixed in 30 seconds for the system with more than 95% recovery rate, It needed 30 minute backwash frequency. During the continuous operation, membrane fouling was analyzed by determining the filtration resistance ($R_i$) and cake layer resistance ($R_c$). At the initial stage, filtration resistance highly influenced the fouling behavior. But after 1.5 hours, cake layer resistance became more important than filtration resistant.

• Elastomers and Composites
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• v.44 no.4
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• pp.397-400
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• 2009

Ozone caused the crack on the surface of a rubber article by oxidation of double bond at room temperature. Wax migrates to the surface of a rubber article and makes a physical barrier to prevent process of ozonation. We investigated change of molecular weight distribution of waxes in unfilled NR, SBR, and BR vulcanizates before and after aging at room temperature for 6 months. Migration and evaporation behaviors of wax in a rubber article at ambient conditions help understand a role of wax as an antidegradant and appearance contamination of a rubber article. The relative intensity distribution of n-alkanes of the NR specimen after the aging was shifted to higher molecular weight compared with the relative intensity distribution before the aging, while those of the SBR specimen before and after the aging did not show a big difference.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.6
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• pp.437-446
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• 2019

Reverse osmosis seawater desalination facilities can extend the cleaning cycle and replacement time of the reverse osmosis membrane by pretreatment process. Selection of pretreatment process depends on water quality. It was attempted in this study to select approriate pretreatment process for the Masan bay, which was high in particles and organic content. For this purpose, performances of pretreatment processes such as filter adsorber (FA), pore controllable fiber (PCF), and ultrafiltration (UF) were compared based on the silt density index (SDI). The SDI value of the filtrate should be less than 3. The study results showed that UF can produce the filtrate quality satisfying the requirement. However, the transmembrane pressure (TMP) of UF increased quickly, reaching 0.6 bar within 4 days. In order to secure stable operation, FA and PCF were combined with UF. The study results showed that combination of PCF and UF was able to extend the filtration duration (more than 2 months) until to reach TMP of 0.6 bar.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.2
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• pp.94-97
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• 2017

A method of improving the anti-fouling characteristics of porcelain insulators was proposed in this study. Functional coating was performed as a method of reducing the surface contamination of the porcelain insulators. The functional coating was applied on a ceramic substrate, which has the same material as the porcelain insulators. After coating the ceramic substrate 2, 3, 4, and 5 times alternately in the horizontal and vertical directions, the surface characteristics according to the thickness of the coating film were analyzed. The optimal process was selected to coat the surfaces of the post insulators and long rod insulators, which are the representative porcelain insulators. After coating, heat treatment was performed for 1 hour at $200^{\circ}C$ in a furnace to secure the durability of the coating film. Compared to the uncoated insulators, the insulators with the functional coating showed significantly improved anti-fouling characteristics as well as excellent adhesion to the coated insulator surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.561-562
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• 2006

The purpose of this study was to investigate the root cause of adhesion of silica and ceria particles during Poly-Si, TEOS, and SiN CMP process, respectively. The zeta-potentials of abrasive particles and wafers were observed negative surface charges in the alkaline solutions. SAC and STI patterned wafers have intermediate values of their composition surface's zeta potentials. The theoretical interaction force and adhesion force of silica and ceria particle were calculated in solution with acidic, neutral and alkaline pH. A stronger attractive force was calculated for silica and ceria particles on wafers in acidic solutions than in alkaline solutions. The theoretical interaction forces of the SAC and STI patterned wafers have intermediate values of their constitution wafer's values. The adhesion forces is observed lower values in alkaline solutions than in acidic solutions. And the ceria particle has lower adhesion than that of the silica particle.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.15-24
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• 2010

Coagulation can be used for pretreatment of NF membrane filtration. Foulants such as organic matter and particulate can be removed effectively with the process while high flux recovery is maintained. Recently various types of polyaluminium coagulants including polyaluminium chloride(PAC) are commercially available for water treatment. This study examines effects of polymeric Al and hydrolysis products of PAC on nanofiltration membrane performance. Dominant hydrolysis products were polymeric Al, $Al(OH)_3$, and ${Al(OH)_4}^{-1}$ at acidic, neutral, and alkaline pH conditions, respectively. Under acidic pH condition, flux decline was increased with increasing PAC concentrations, possibly due to polymeric Al adsorption on membrane pore and/or surfaces. For neutral and alkaline pH conditions, little flux decline was observed with increasing PAC concentrations except the highest ${Al(OH)_4}^{-1}$ concentration, with which rapid flux decline was shown. Removal of ionic matters was also varied with pH conditions in this study. Especially, conductivity removal was substantially low and $Ca^{2+}$ concentration in the permeate was quite high at neutral pH condition.

• KSBB Journal
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• v.10 no.1
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• pp.1-8
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• 1995

A lot of water soluble proteins and lipids are released from minced mackerel meat and lost into the washing waste during the leaching process of Kamaboko or surimi manufacture. The removed proteins and lipids are not only an edible things but also a big burden for treating the wastewater. In order to recover the proteins from the effluent and to use as food stuff, the "pH-shifting" treatment, a modified isoelectric point precipitation method, was tried. This method is based on a myogen-aggregation phenomenon, which occurs when a solution of sarcoplasmic proteins is acidified or alkalified beyond the critical pH zone of 2∼3 or 12∼13 respectively and then neutralized. The maximum amount of precipitation was obtained by shifting the pH of the wastewater from original pH to isoelectric point (pH 4) or alkali pH 12 and then changing to neutral pH. The precipitates were easily collected by filteration or centrifuging at 10,000rpm. The oils which were only floating in the washing wastewater are easily recovered by seperating with oil separator after pouring. The recovered proteins were slightly denaturated during this pH shifting precipitation process, while the composition of amino acids was good balance as a food.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.379-385
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• 2005

This study was conducted to find out a useful bioremediation technology for heavy metal contaminated soil and water. We isolated strain CPB from heavy metal contaminated soil and evaluated the tolerance level and adsorption capacity of strain CPB to heavy metals (Strain is not determined yet). Strain CPB showed variable tolerance limit to different kinds heavy metal or concentrations of heavy metals. The growth of strain CPB was significantly inhibited by mixed heavy metals (Cd+Cu+Pb+Zn) than that of by single heavy metal. Strain CPB showed high binding capacity with Pb (Pb>Cd>Cu>Zn). In general, strain CPB showed high uptake of heavy metals such as Pb, Cd and Cu. It was observed that the capacity of heavy metal uptake from mixture of heavy metals was reduced in comparison with single heavy metal treatment. But total contents of heavy metal bound with cell in mixed heavy metal showed higher than in single heavy metal treatment. Heavy metal adsorption in cells was affected by several external factors, such as temperature and pH etc.. The optimum temperature and pH of the adsorption of heavy metal into cells were ca. $25{\sim}35^{\circ}C$ and pH ca. $5{\sim}7$, respectively. A large number of the electron dense particles were found mainly on the cell wall and cell membrane fractions, which was determined by transmission electron microscope. Energy dispersive X-ray spectroscopy revealed that the electron dense particles were the heavy metal complexes the substances binding with heavy metals.

• Journal of Environmental Policy
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• v.5 no.4
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• pp.127-154
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• 2006

It has been widely accepted that the environment is an important determining factor of human health. Appreciating the relationship between the environment and human health, Korean government has begun to deal with issues of environmental health. The government proclaimed the year of 2006 to be the first year of Environmental Health and established "The Environmental Health Plan for the next 10 Year". In order to achieve the goals in the plan, there are necessary considerations such as support systems for environment health related research, investigation, law, institution, administration, and so forth. This study suggests basic principles required to establish a legal regime of environmental health which is to implement the environmental health policies in Korea. Several cases of foreign legislation and policy relevant to environmental health are reviewed. Also, existing related legal system in Korea are analysed considering legal and institutional elements for establishing an effective environmental health policy. The main purpose of amending legal system related environmental health is to protect both public health and the soundness of ecosystem. To reach the goals effectively, the concept of 'environmental health' should be clearly established and presented. In addition, an advanced prevention system, including investigation and prevention of the cause of environmental diseases and risk assessment based on the precautionary principle, are substantial in the environmental health legislation. Also the environmental health law should guarantee public participation in decision making as well as the first consideration of susceptible or vulnerable population. This study concludes that the expected legislation related to environmental health should be a nonnative instrument not only for integrating each environmental protection scheme but also for establishing and implementing the policy.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.557-564
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• 2000

This study is aimed to develop the adsorbent which can effectively remove toxic hydrophobic organic compounds from the aqueous phase. The emphasis was made to elucidate the adsolubilization behavior of sparingly soluble organic compounds (SSOCs) into the cetyltrimetylammonium bromide(CTAB) layer formed on anthracite by the partition coefficient. The amount of SSOCs removed from aqueous solution was increased with increase of the amount of CTAB coated on the surface and wich increase of SSOCs's hydrophobicity. With the surface-modified solid shown in above. chloroform and benzene at the initial concentration of $6{\times}10^{-4}M$ were removed over 95%. Experimentally determined partition coefficient($K_d$) values between organo-anthracite and organics were 4~25 times higher than theoretical $K_d$ values of same organics Organo-anthracite formed by the addition of the CTAB can effectively immobilize organic contaminants dissolved in landfill leachate and can also be applicable to wastewater treatment containing toxic hydrophobic organic compounds such as chloroform and benzene.