• Journal of the Korea Organic Resources Recycling Association
• /
• v.27 no.2
• /
• pp.13-18
• /
• 2019

Sewage sludge treatment is increasing every year due to improvement of living and urbanization. However, interest in anaerobic digestion which is one of the recycling technology. There is anaerobic digestion of increasing due to limitations of ocean dumping and final disposal. But, the limit of anaerobic digestion efficiency due to the advanced treatment of sewage has been limited, and studies for solubilization technology have been actively conducted. Therefore, in this study, we aimed to investigate the variation of generation of scum and the solubilization efficiency in the application of pre-treatment of ozone reaction and the change of properties of digested sludge with wet milling. There are results of VS/TS increased by 4.4% and $SCOD_{cr}/TCOD_{cr}$ increased by 9.4% by wet milling alone. In addition, the increase of the specific surface area due to which the reduction of the particle size of the solid content of the sludge in the ozone reaction caused by wet milling decreased the generation rate of scum at 14.3% and increased VS/TS at 2.1%, compared with the ozone reaction alone. From these results, it is expected that the application of wet milling can be increased the contact efficiency with solids in the sludge during ozone reaction with suppress scum and increase the efficiency of the subsequent process in anaerobic digestion.

• Proceedings of the KIEE Conference
• /
• 2002.11a
• /
• pp.206-208
• /
• 2002

A novel ozonizer has been developed using a high frequence surface discharge and a high purity ceramic as its dielectric component. And A cylindrical thin compound ceramic catalyst in reactor is adhered to inside of the film-like outside electrode. An ac exciting voltage with frequency to 0.6 kHz from 1.0 kHz and $4{\sim}6$ kV of peak-to-peak is applied between the electrodes to produce a stable high-frequency silent discharge for generation of ozone. A substantial reduction of the exciting voltage is also enabled by using a thin ceramic. As a result, the ozonizer can easily produce ozone concentration(50 $g/m^3$ for oxygen) and power efficiency(240 g/kWh for oxygen) without using a special enrichment means.

• Journal of Korea Water Resources Association
• /
• v.30 no.3
• /
• pp.235-245
• /
• 1997

A pilot scale study for removing odor and trihalomethane formation potential (THMFP) was investigated in the standard water treatment plant equipped with ozone oxidation and granular activated carbon (GAC) adsorption processes. The removal efficiency of dissolved organic carbon (DOC) in the pilot scale standard water treatment process (PSWTP) was about 25%, however, no more removal in the ozone oxidation process. On a GAC after 30 days operation, DOC removal efficiency was about 75%. Odor removal efficiency was about 30% in PSWTP, 60% in ozone oxidation, and almost complete in well as DOC. Mid-1 and 2 that showed breakthrough in odor inducing material as well as DOC. Mid-1 and 2 chlorination was able to reduce trihalomethanes (THM) by 25% compared to prechloringation, while postchlorination alone could reduce them by 30%.

• Bulletin of the Korean Space Science Society
• /
• 2004.10b
• /
• pp.372-375
• /
• 2004

The UV radiometer payload was launched successfully from the west coastal area of Korea Peninsula aboard KSR-III on 28, Nov 2002. KSR-III was the Korean third generation sounding rocket and was developed as intermediate step to larger space launch vehicle with liquid propulsion engine system. UV radiometer onboard KSR-III consists of UV and visible band optical phototubes to measure the direct solar attenuation during rocket ascending phase. For UV detection, 4 channel of sensors were installed in electronics payload section and each channel has 255, 290, 310nm center wavelengths, respectively. 450nm channel was used as reference for correction of the rocket attitude during the flight. Transmission characteristics of all channels were calibrated precisely prior to the flight test at the Optical Lab. in KARI (Korea Aerospace Research Institute). During a total of 231s flight time, the onboard data telemetered to the ground station in real time. The ozone column density was calculated by this telemetry raw data. From the calculated column density, the vertical ozone profile over Korea Peninsula was obtained with sensor calibration data. Our results had reasonable agreements compared with various observations such as ground Umkhr measurement at Yonsei site, ozonesonde at Pohang site, and satellite measurements of HALOE and POAM. The sensitivity analysis of retrieval algorithm for parameters was performed and it was provided that significant error sources of the retrieval algorithm.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.213-213
• /
• 2011

Gold catalysts supported on TiO2 have shown a unique catalytic behavior on CO oxidation, depending on surface effects. Particle size has an influence on the surface activity. To make monodisperse Au nanoparticles, organic capping ligands, such as alkylthiols, were used by a "greener" synthesis method [1,2] and Au nanoparticles were deposited on TiO2. However, organic capping ligands must be removed for high catalytic activities by the Au nanoparticles without changing the Au size [3]. We used UV ozone treatment to decompose thiol ligands. The samples have been characterized by X-ray photoelectron spectroscopy to examine the surface modification by UV ozone treatment. We show the size distribution of the gold nanoparticles by light scattering analysis and transmission electron microscopy. Au/TiO2 have been prepared using the wetness impregnation method. The catalytic performance of CO oxidation over Au supported on TiO2 under oxidizing reaction conditions (40 Torr CO and 100 Torr O2) were tested. The results show that the catalytic activity depends on particle size and the time of UV ozone exposure, which suggests the role of sulfur bonding in determining the catalytic activity of Au/TiO2 catalysts.

• 대한예방의학회:학술대회논문집
• /
• 2001.10a
• /
• pp.318-319
• /
• 2001

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.04a
• /
• pp.377-378
• /
• 2000

1957년 국제지구물리관측년 (IGY：International Geophysical Year) 계획 이래 대기중의 오존전량(total ozone)과 대기중의 수직 층별 오존량의 측정을 위해 본격적으로 전세계적 오존관측망이 운영되기 시작하였다. 이 시점을 기준으로 오존에 관한 연구는 전지구적인 오존전량의 감소경향과 남극상공 성층권에서의 오존량 파괴에 집중되어왔다. 그러나 대기중 오존의 행태를 더 정확하게 이해하고, 각각의 대기권이 서로의 오존량에 미치는 영향을 이해하기 위해서는 대기중 오존의 수직분포에 관한 연구가 대단히 중요하다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.04a
• /
• pp.55-56
• /
• 2000

급격한 도시화는 도시의 기후변조와 함께 오존오염 문제를 야기 시켰다. 즉 지표오존(ground-level ozone)의 고농도 현상이 도시대기환경의 주된 관심사가 되었고, 이를 해결하기 위해 여러 연구가 국내·외에서 지역특성에 맞게 활발히 이루어지고 있는 실정이다. 일반적으로 지표오존은 전구물질의 배출량 및 도시의 지형학적 위치와 기상학적 특성에 따라 생성·소멸·이류 메카니즘이 다르게 나타난다. 따라서 이러한 국지적 특성의 고려는 지표오존의 고농도분석에 있어 반드시 수반되어야 하며, 이를 바탕으로 최종적으로 농도예측이 이루어 져야 할 것이다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.04a
• /
• pp.327-328
• /
• 2002

대기권 오존의 90%정도가 성층권의 15-30km 부근에 존재한다. 성층권에 존재하는 오존은 대류권에서 생성된 오존과 화학식은 동일하지만 대기 중의 생성과정과 유발시킬 수 있는 피해 정도가 다르다. 성층권 오존은 직접적으로 생체 DNA 변성, 피부암 등을 야기 시키는 자외선을 흡수ㆍ차단시켜 주므로 인간 및 동ㆍ식물에게는 중요한 기체이다. 이러한 성층권 오존이 인간에 의해 배출되는 오염물질 염화불화탄소(CFCs), 할로겐 가스등에 의해 파괴되고 있다. (중략)

• Journal of the Korean earth science society
• /
• v.24 no.3
• /
• pp.216-233
• /
• 2003

This study delineates the phenomena related with global environmental changes such as global warming, ozone depletion, and El Ni${\tilde{n}}$o/Southern Oscillation (ENSO) noted in the Antarctic. Retreat of ice cliffs, glaciers, and calving of ice shelves indicate the effects of recently aggravated global warming. The ice cliff located at Marian Cove, King George Island, South Shetland Islands off the Antarctic Peninsula has been observed to be retreating faster in the last 7 years than in the previous 38 years since 1956. There are some indications of temperature and precipitation changes associated with ENSO around King Sejong Station. The regression analyses indicate significant trends such as a decrease in the total amount of ozone and an increase in ultraviolet radiation which was seen by a satellite (TOMS-EUV) in September and October which correspond to ozone-hole season over King Sejong Station. Increase of UV radiation due to the ozone depletion in the Antarctic has changed the growth rate of marine organisms. It may also result in changes to the productivity, biomass, and species composition of marine organisms which can affect the whole marine ecosystem. The recent ice-core drilling over Lake Vostok has been reviewed with emphasis on the four cycles of glacial stages over the past 420,000 years. It is time to show more interest in mainland Antarctica through investigations of the coring and vast ice sheet, terrestrial geology, and upper atmospheric sciences in order to understand the past environmental changes and to predict possible changes to the environment in the future.