• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.289-296
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• 2007

Porous media for sewage treatment were developed through a pyrolysis process of food wastes with loess in the study. This work was carried out in two consecutive stages; in the first stage, new porous media were prepared through a high temperature pyrolysis process, and then the resultant media were applied to a simple lab-scale sewage treatment process in the second stage. To determine the optimum operating conditions of pyrolysis and mixing ratio of materials, physical properties such as specific surface area, porosity and compressive strength of final products were analyzed. The removal efficiencies of TOC and COD were measured to evaluate the effectiveness of resultant porous media. As a result of the experiment, we found that the best mixing ratio of food wastes to loess was 1 : 1 at $1,100^{\circ}C$. Average porosity of the developed media was 37.0%, in which pore size ranged from 1 to $20{\mu}m$, showing quite vigorous microbial activation. After immersing the media into a reactor for sewage treatment for eight days, removal efficiencies of TOC and COD were 87.3% and 85.0%, respectively.

• KSBB Journal
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• v.13 no.1
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• pp.83-89
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• 1998

Using a cellulose macroporous microcarrier, HeLa cells were cultivated in 100mL spinner flask(Bellco Co., USA) and confluent cell laden microcarriers were subcultured by bead-to-bead cell transfer method. In macroporous mcirocarrier-HeLa system viable suspended cells played an important role in bead-to-bead cell transfer and that could be increased by use of RPMI-1640, a calcium-ion-reduced-media and high speed agitation. Successful bead-to-bead cell transfers were performed continuously three time in spinner flask. We applied this technique to produce recombinant Vaccinia virus which express $\beta$-galactosidase. Recombinant protein yield of bead-to-bead transferred culture was comparable to conventional microcarrier cultures that were inoculated by cells detached from T-flask. Although trypsinization is a useful method for subculturing microcarriers in some cases, that process adds quality control problem and handling steps to large scale cell production. There fore, bead-to-bead cell transfer technique offers another convenient and efficient scale-up method for continuous microcarrier cultures.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.927-932
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• 2009

Toxic and recalcitrant organic pollutants in wastewaters can be effectively treated when advanced oxidation and biodegradation are combined, ideally with intimate coupling, in which both processes occur simultaneously in the same system. One means to achieve intimate coupling is to coat nanoscale $TiO_2$ on the outside of macroporous biofilm carriers. This study investigated the kinetics of photocatalysis with $TiO_2$-coated porous carriers. The carriers were made of polyvinyl alcohol (PVA) and coated with $TiO_2$ using a low-temperature sol-gel process. The $TiO_2$-coated carriers catalyzed the oxidation of methylene blue (MB) effectively under irradiation of UV light. The overall reaction rate with adsorption and photolysis saturated at high MB concentration, and approached the adsorption rate, which was first order for all MB concent rations. This result indicates that adsorbed MB may have slowed photocatalysis by blocking active sites for photocatalysis. The overall kinetics could be described by a quasi-Langmuir model. The estimated maximum specific (per unit mass of $TiO_2$) transformation rate of MB by the $TiO_2$-coated carriers was four times larger than that obtained from slurry-$TiO_2$ reactors. This observation demonstrated that the $TiO_2$ present as a coating on the carriers maintained high efficiency for transforming recalcitrant organic matter via photocatalysis. These findings serve as a foundation for advancement of an intimate coupling of photocatalysis to biodegradation.

• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.224-226
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• 2002

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.192-192
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• 2003

오염된 폐수를 처리하는 과정으로 다양한 방법이 사용되고 있으나, 담체를 이용하여 미생물을 배양하고, 미생물에 의해 정수하는 방법이 이용되고 있다. 이를 위해서는 미생물을 배양을 위한 담체의 조건으로 다양한 크기의 연속기공을 갖고, 젖음성과 표면거칠기가 높으며, 이들 중 초기 미생물번식의 조건을 제공하는 기체 포집용 미세기공을 보유하고, 미생물이 성장할 수 있는 수백 $\mu\textrm{m}$까지의 다양한 크기의 연속된 기공을 갖는 미생물 담체용 다공성 세라믹스의 제조를 목적으로 본 연구를 행하였다. 본 연구는 다양한 크기의 기공분포를 형성하기 위하여 첨가물로 activated carbon과 무기염, 고분자 binder를 활성알루미나 기지재료에 사용하여 수열반응에 의해 각각의 물질이 형성할 수 있는 기공의 크기를 확인하고, 수 nm에서 수백 $\mu\textrm{m}$까지의 연속된 기공이 존재하는 담체를 제조하였다. 수열조건과 첨가물의 양에 따라 수은침투가압을 이용하여 기공의 크기와 분포를 측정하고 평균기공률을 얻을 수 있었고, 압축강도를 측정하고, 기공의 형상을 주사전자현미경을 통해 확인하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.435-440
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• 1996

삼중수소 제거 공정에 이용되는 소수성 고분자촉매의 담체인 스티렌-디비닐벤젠 공중합체의 제조 특성을 실험하였다. 스티렌-디비닐벤젠 고분자담체의 제조시 담체의 표면 특성에 대한 중합용액의 안정화 영향을 실험한 결과 약 40~55$^{\circ}C$의 범위에서 2시간 이상 용액을 안정화 시키는 것이 가장 바람직하였다. 또한 후처리 방법은 담체를 건조시키기 전에 용매를 제거하는 방법이 가장 우수한 기공 특성을 나타내었다. 담체의 입자 크기는 계면활성제의 농도가 낮을수록 더 크게 생성되었지만 용액의 점도가 증가하면 계면활성제의 영향이 감소됨을 알 수 있었다.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.200-205
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• 2005

We have prepared the porous carrier that has high capacity for immobilization of microorganisms and adsorption capacity for cation using fly ash in the previous work. In this study, we investigated the characteristics of piggery wastewater treatment in comparison with commercial carrier and conventional activated sludge process by continuous-flow fixed biofilm process in laboratory scale at the same experimental conditions to develop the biofilm process using porous fly ash carrier for wastewater treatment. As a result, the prepared fly ash carrier showed that removal efficiency of COD, TN and $NH_4{^+}-N$ items were 80%, 77% and 65%, respectively, which were higher efficiency than the commercial carrier and conventional activated sludge process. And the result of measurement for immobilized microorganisms after treatment showed higher capacity than the commercial carrier, and it was confirmed by SEM observation on fly ash carrier that the colony of microorganisms was stably formed.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.945-951
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• 2012

The effect of photocatalyst-carrying media porosity on the photocatalytic removal efficiency of malodor and VOC of waste air was evaluated when the photocatalytic removal efficiency of porous silica-based media was compared with that of glass bead as control. The amount of photocatalyst coated on the surface of porous silica-based media was observed to be $1,716.3{\mu}g/cm^2$, which was 250% as much as that of nonporous glass bead (control) of $670{\mu}g/cm^2$. The removal efficiencies of hydrogen sulfide and toluene in case of porous silica-based media were observed to be 22% and 82%, respectively, while the removal efficiencies of hydrogen sulfide and toluene in case of nonporous glass bead media were observed to be 19% and 53%, respectively. Therefore, the removal efficiencies of hydrogen sulfide and toluene increased by 16% and 55%, respectively, when the removal efficiencies of porous silica-based media were compared with those of nonporous glass bead media. Thus the increment ratio of the removal efficiency of toluene was observed to be 3.4 times higher than that of hydrogen sulfide.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.542-548
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• 2005

A fluidized bed reactor containing porous media has been known to be effective for nitrogen and organic matters removal in wastewater. The porous media which attached microbes plays important roles in simultaneous nitrification/denitrification (SND) due to coexistence of oxic, anaerobic and anoxic zone. For SND reaction, oxygen and organic substrates should be effectively diffused from wastewater into the intra-carrier zone. However, the overgrowth heterotrophic microbes at the surface of porous media may restrict from substrates diffusion. From these viewpoints, the existence and effect of heterotrophic bacteria at surface of porous media might be the key point for nitrogen removal. A porous media-membrane hybrid process was found to have improved nitrogen removal efficiency, due to stimulated denitrification as well as nitrification. Microelectrode studies revealed that although intra-media denitrification rate in a conventional fluidized bed was limited by organic carbon, this limitation was reduced in the hybrid process, resulting in the increased denitrification rate from 0.5 to $4.2\; mgNO_3-N/L/hr$.

• Korean Journal of Materials Research
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• v.10 no.9
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• pp.619-623
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• 2000

Alumina membrane was prepared by sol-gel coating method using boehmite powder(${\Upsilon}-AlOOH$). The supported and the unsupported alumina membrane were fabricated to investigate the phase transformation and change of microstructure. It is important to control the homogeneous pore size and distribution in application of filtering process. The ${\theta}-to\;{\alpha}-AL_2O_3$ phase transformation (XRD) and the change of microstructure was investigated using scanning electron microscopy(SEM). XRD patterns showed that the supported membrane had $100^{\circ}C$ higher ${\theta}-to\;{\alpha}-AL_2O_3$ transformation temperature compared to the unsupported membrane. The similar effect was also observed for microstructural change of the membrane.