• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.474-484
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• 2005

Biological treatment is a promising alternative to conventional air pollution control methods. Bioreactors for air pollution control have found most of their success in the treatment of dilute and high flow waste air streams containing volatile organic compounds and odor compounds. They offer several advantages over traditional technologies such as incineration or adsorption. These include lower treatment costs, absence of formation of secondary pollutants, no spent chemicals, low energy demand and low temperature treatment. The most widely used bioreactor for air pollution control is biofilter, but it has several limitations. In the past years major progress has been accomplished in the development of vapor phase bioreactor, in particular biotrickling filters. Biotrickling filters are more complex than biofilters, but are usually more effective, especially for the treatment of compounds which are difficult to degrade or compounds that generate acidic by-products. While the level of understanding of biotrickling filtration process for VOCs still remains limited, the evident success of biotreatment of VOC in air stimulated the pursue of acitve research. This paper presents fundamental and theoretical/practical aspect of air pollution control in biotrickling filter. Special emphasis is given to the operating parameters and the factors influencing performance for air pollution control in biotrickling filter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.499-504
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• 2010

It is important to determine the exact soot mass in a DPF system in order to control the timing of PM regeneration. The soot mass accumulated in a filter can be estimated from the pressure drop in the filter and the exhaust gas flow rates. In this study, the soot index is defined as the pressure drop in the DPF divided by the pressure drop in a DOC. An effective signal processing method for determining the soot index is proposed; the results yielded by this method indicate good correlation between the soot index and the amount of soot loaded into the filter for both steady-state and transient-state operating conditions in a 3L diesel engine for passenger vehicles.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.6
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• pp.633-640
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• 2008

In this research, the $3.6m^3/day$ scale pilot plant consisting preozonation, coagulation, flocculation, and ceramic membrane processes was operated for long term period to evaluate the validity of ceramic membrane filtration process for treating lake water containing high concentration manganese. The higher concentration of dissolved manganese($Mn^{2+}$) was effectively oxidized to the bigger insoluble colloidal manganese ($MnO^2$) by 1~2 mg/L ozone. The colloidal manganese reacted with coagulant (poly aluminium chloride, PAC) and then formed the big floc. Ceramic membrane rejected effectively manganese floc during membrane filtration. Dissolved organic carbon(DOC) removal was dependent upon $Mn^{2+}$ concentration. While average $Mn^{2+}$ concentration was 0.43 and 0.85 mg/L in raw water, DOC removal rate in preozonation was 26.5 and 13.5%, respectively. The decrease rate of membrane permeability was faster without preozonation than with preozonation while membrane fouling decreased with NOM oxidation by ozone. In conclusion, raw water containing high concentration of manganese can be effectively treated in preozonation-coagulation-ceramic membrane filtration system.

• Membrane Journal
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• v.6 no.2
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• pp.109-116
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• 1996

This work is a fundamental study for applying hybrid process coupling adsorption with microfiltration to waste-water treatment. Phenol was separated by adsorption on powdered activated carbon, adsorbed phenol with activated carbon was separated by microfiltration. As the particle size in suspension increased, filtration resistance decreased, and effect of particle concentration on resistance was less pronounced. The rate of uptake was greatly dependent on the degree of phenol loading. For a smaller amounts of activated carbon, the change of permeate concentration before break point and phenol loading with time were steeper than in the case of large amounts. Permeate concentration before break point decreased with decreasing particle size, this could be due to the increase of outer surface of particle and film mass transfer coefficient.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.123-128
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• 2005

Buk-myeon area in Changwon is located near Nakdong river and not short of quantity of river but the water quality and quantity is changed extremely by seasons, and Fe, Mn, Cu are found at the base rock underground water. Therefore, bank filtrated water developing is settled. At this research, Pilot-Plant is built to find out Fe and Mn are detected and eliminated by biological process and the ammonia is exceeded the drinking water quality criteria at the bank filtrated water while designing and facilitating the local water supply facilities at Buk-myeon area. Also, check results of the changed treatment process of automatic precipitating filter, which is producing and supplying drinking water, and analyzing the Biological Process Effectiveness by building and running Buk-myeon Water Treatment Facility, which could provide $10,000m^3/day$.

• Membrane Journal
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• v.14 no.1
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• pp.66-74
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• 2004

Total resistance of membrane in a micro-filtration system using a metal membrane was mainly attributed to the permeate resistance of cake layer($R_c$), which was formed by deposited particles from the physico-chemical interactions of solids on membrane surface. Intermittent back ozonation was highly effective than the air backwashing for fouling reduction. As far the operational effect, under same ozone injection, the increase of gas flow-rate was more favorable than the increase of injection time far the recovery of permeation flux. As the filtration time was longer, the effect of flux recovery by intermittent back-ozonation decreased. Therefore, it is preferable to operate membrane cleaning before the foulant is consolidated on membrane surface.

• KSBB Journal
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• v.14 no.2
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• pp.230-234
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• 1999

To improve the crossflow untrafiltration flux, we applied periodic oscillations in transmembrane pressure gradient in order to promote fluid turbulence by inducing repeated compression and relaxation of the cake/gel layer. The oscillatory forms used were square-, sine-, triangle-wave, and pumping interruption. The permeate flux profiles were mathematically simulated and compared with the experimental data. The result showed the periodic pumping interruption most effectively improved the overall flux by up to about 32%. Enough pumping off-time, at least on the order of tens of seconds, was needed to allow the solutes in the layer to diffuse back to the bulk phase. It was better to start the oscillations earlier before the layer was fully established. The square-wave oscillation yielded about 11% increase, which was particularly pronounced in the later part of the filtration. Either the amplitude or the period of the oscillations resulted little influence on flux.actate ester, and lactate ester produced in esterification reaction was distilled simultaneously with hydrolysis reaction into lactic acid. When the yields of lactic acid recovered by batch reactive distillations with various alcohols were compared, the yield of lactic acid was increased as the volatility of lactate ester was increased. In this batch reactive distillation, because the mixtures condensed in partial condensor were flown to reboiler through distillation column, the recovery yield of lactic acid was affected by operation temperature of partial condensor. Hydrolysis reaction into lactic acid in distillation column rarelyoccurred because of short retention time of lactate ester and water. Lactate ester was reacted into lactic acid in reboiler.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.857-864
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• 2009

This study aimed at developing the two stage and dual filtration system. It has a sand + activated carbon layer above the underdrain system and a sand layer above the middledrain system for pretreatment. When retrofitting an old filter bed or designing a new one, this technology can substitute the existing sand filter bed without requiring a new site. In order to extend the filtering duration, the upper layer of the filter bed consists of the rapid sand filtration with large particles which pre-treats and removes coarse particles and turbidity matters. The middle layer has biological activated carbon(BAC) and granular activated carbon(GAC) to eliminate dissolved organic matters, disinfection by-products precursors etc. The lower layer consists of the sand filtration for the post filtering mode. In this study, a pilot plant of two stage and dual filtration system was operated for 4 months in the S water treatment plant in Kyounggi-Do. The stability of turbidity was maintained below 1NTU. The TOC, THMFP and HAAFP were removed about 90% by two stage and dual filtration system, which is almost 2 times higher than S WTP. From analysis result of HPC along the depth of activated carbon + sand layer at 2nd stage, microorganism was mostly not detected, however, increment of HPC was shown as it becomes deeper. It indicates that growth of microorganism is occurred at activated carbon layer.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.448-457
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• 1999

Citrus fruits are consumed worldwide due to their unique flavor and nutrition value. It is necessary to remove the haze material as well as to minimize the loss of major compounds such as organic acids, sugars, and ascorbic acid in membrane processes for clarification of juice. The objective of our research was to select the best membrane among one surface filter (Whatman No.4) and five microfiltration filters (GF/A, GF/D, GF/F, Gelman, and SM). Tangerine fresh blended with three times of water was partially clarified with 170 mesh followed by prefiltration in a Samduck filtration system. The best membrane was selected by measuring the amounts of major compounds in the permeates as well as the flux which were statistically analyzed with SAS program. The foulants on the membrane surface were observed by SEM. The flux of GF/A and GF/F decreased with time at probability 0.10. Gelman, SM, and GF/D maintained the stable flux. Gelman showed the highest total scores including nutritive value (the amounts of citrate, malate, and ascorbic acid) and purchasing need (brix and color). Therefore, the microfiltration membrane process was a very effective method in tangerine juice clarification and Gelman type A/E was proved to be the best membrane among the five microfiltration membranes.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.327-328
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• 2003

경유자동차는 연료 특성상 매연을 포함한 입자상물질을 다량 배출하고 있으며, 이러한 디젤입자상물질은 인체에 유해한 발암성 및 돌연변이원성 물질들을 함유하고 있기 때문에 호흡 등을 통한 인체 유입시 건강에 매우 유해하다. 그러므로 디젤입자상물질을 저감시키기 위한 여러 가지 기술들 중 발생된 배출가스가 배기관을 통해 대기중으로 배출되기 전에 엔진 연소실과 배기관 사이에 후처리장치와 같은 기술들을 이용하여 이를 저감시키고 있다. 본 연구에서는 후처리장치들 중 세라믹필터에 백금과 같은 산화성이 우수한 촉매를 코팅하여 만든 촉매식 매연여과장치(DPF ; diesel particulate filter, SK제공)를 사용하였을 때 입자저감성능 및 입자크기별 분포특성을 살펴보고자 하였다. 이를 통해 도시대기오염 저감대책을 기초자료 및 환경학적, 보건학적 연구에 적극 활용하고자 한다. (중략)