• 한국환경과학회지
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• 제19권1호
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• pp.89-96
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• 2010

The separation of $TiO_2$ wastewater carried out by an electrocoagulation/flotation process, which had various operating parameters. The effect of electrode material (aluminum and four dimensionally stable electrode), applied current (0.07~0.5 A), electrolyte concentration (0~1 g/L), solution pH (3~11), initial turbidity (1000~20000 NTU) and suspended solid concentration (5000~25000 mg/L) were evaluated. Turbidity removal efficiency of the soluble anode (aluminum), which could produce metal ions, was higher than that of the dimensionally stable electrode. Considering operation time, turbidity removal and electric power, optimum current was 0.19 A. The more NaCl dosage was high, the less electric power was required. However, optimum NaCl concentration was 0.125 g/L considered removal efficiency, operation time and cost. Initial $TiO_2$ concentration did not affected turbidity removal on the electrocoagulation/flotation operation. The electrocoagulation/flotation process was proved to be a very effective separation method in the removal of $TiO_2$ from wastewater.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.865-868
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• 2011

배가스로부터 이산화탄소의 분리 특성을 파악하기 위해 유기 화합물인 하이드로퀴논을 이용하여 크러스레이트 화합물을 형성하였다. 형성된 크러스레이트 화합물은 고체 NMR 및 라만 분광법을 이용하여 기체의 포집 거동을 확인하였으며, 기체 분리 효율을 계산하기 위하여 원소 분석기를 통한 정량분석도 함께 수행하였다. 분석 결과 배가스에 포함된 이산화탄소는 질소에 비해 동일한 조건에서 크러스레이트 화합물 내로 더 잘 포집되는 것으로 확인되었다. 또한 다양한 압력에서 형성된 시료들을 분석한 결과, 이러한 이산화탄소의 선택적 포집 특성이 매우 낮은 압력에서도 뚜렷한 것으로 확인되어 추가적인 에너지 소모를 적게 하면서도 배가스로부터 이산화탄소를 대규모로 분리/회수하는 것이 가능할 것이라 판단된다. 본 연구에서 얻어진 결과는 향후 배가스에 대한 분리 응용 기술이나 혼합 가스의 선택적 분리와 같은 분야에서 중요한 정보를 제공할 수 있을 것으로 기대된다.

• 상하수도학회지
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• 제10권4호
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• pp.45-54
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• 1996

Effects of temperature on the efficiency of the Upflow Anaerobic Sludge Blanket(UASB) process for treatment of wastewater from a starch and related products manufacturing industry were investigated using laboratory scale reactors equipped with two types of Gas-Solid Separator(GSS). Both fresh digested sludge and granular sludge stored nearly for one year at room temperature were good as a seeding material. The reactors seeded with aged granular sludge showed slow start-up, however, lowered activity at the initial period was recovered gradually. The GSS with an inner cylinder was proved to be effective in liquid-solid separation compared to the conventional type. Although the rate of organic removal and gas production per unit volatile suspended solids in the reactor reduced significantly as the temperature varied from 35 to $20^{\circ}C$, possibility of operation at low temperatures was shown as a result of gradual buildup of volatile suspended solids in the bed. Stable operation with a reduced efficiency was possible at a COD loading of $5-8kg/m^3/day$ at a temperature as low as $20^{\circ}C$.

• 상하수도학회지
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• 제24권5호
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• pp.537-548
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• 2010

Recently the Government has announced updated water quality standards for wastewater treatment effluent (become effective in 2012). That includes highly enforced regulations for T-P, BOD and COD, and a large budget, in particular for phosphorus removal, was set by the Ministry of environment. Chemical coagulation destabilizes colloidal particles so that particles grow to larger flocs, and solid particles are removed by solid-liquid separation. The efficiency of chemical coagulation depends on a various factors, including coagulant types and costs, construction and operation costs for the treatment facilities and so on. The proper selection should be based on the treatment efficiency of coagulants and underlying costs. The current research was to evaluate the treatment efficiencies of coagulants on a variety of wastewater influents and to develop saturation curves for several water quality parameters. Typical $Al_2(SO_4)_3$ and $FeCl_3$ were tested under a range of coagulant concentrations. The pollutant removal efficiencies of chemical treatment both for the $Al_2(SO_4)_3$ and $FeCl_3$ were especially high for T-P, followed by SS, BOD and COD. Correlation test also proved the highest relationship between SS and T-P.

• 한국정밀공학회지
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• 제29권7호
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• pp.799-804
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• 2012

Recently micro-nano structures has widely been reported to improve the performance of waterproof, heat isolation, sound and light absorption in various fields of electric devices such as mobiles, battery, display and solar panels. A lot of micro-sized holes on the surface of thin film provide excellent sound, or heat, or light transmission efficiency more than solid film and simultaneously nano-sized protrusions around micro hole increase the hydrophobicity of the surface of thin film because of lotus leaf effects as generally known previously. In this paper new rapid fabrication process with 355 nm UV laser ablation was proposed to get micro-nano structures on the surface of thin film, which have only been observed at higher laser fluence. Developed thin micro-nano structured film was also investigated the hydrophobic property by measuring the contact angle and demonstrated the possibility to apply to water droplet separation.

• 한국막학회:학술대회논문집
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• 한국막학회 1993년도 춘계 총회 및 학술발표회
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• pp.1-11
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• 1993

Cartridge filters are widely used in liquid-solid separation processes. To select a proper filter system for the requirements of a given application, a knowledge of filter efficiency and dirt capacity is required. The filter manufacturer needs to provide data which are based on test procedures simulating real parameters on a laboratory scale. There does not exist at present a standard for liquid filter testing (with the exception of the Multipass Test to ISO4752 for hydraulic filters). Users have to work with data based on different test procedures. This paper will discuss principles of filter testing, efficiency andd dirt capacity results as a function of test parameters, and data interpretion to provide a guideline for the end user.

• 한국수소및신에너지학회논문집
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• 제25권2호
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• pp.122-130
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• 2014

Attrition characteristics of WGS catalysts for pre-combustion $ CO_2$ capture were investigated to check attrition loss of those catalysts, to check change of particle size distribution during attrition tests, and to determine solid circulation direction of WGS catalysts in a SEWGS system. The cumulative attrition losses of two catalysts increased with increasing time. However, attrition loss under humidified condition was lower than that under non-humidified condition case for long-term attrition tests. Between two catalysts, attrition loss of PC-29 catalyst was higher than that of commercial catalyst for long-term attrition tests. However, the commercial catalyst generated much more fines than PC-29 catalyst during attrition. Therefore, we conclude that the PC-29 catalyst is more suitable for fluidized bed operation if we take into account the separation efficiency of cyclone. Based on the results from the tests for the effect of humidity on the attrition loss, we selected solid circulation direction from SEWGS reactor to regeneration reactor because the SEWGS reactor contains more water vapor than regeneration reactor.

• 한국환경복원기술학회지
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• 제10권6호
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• pp.88-98
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• 2007

The control of nonpoint source pollution from the urban paved areas with high imperviousness in is required to improve the water quality of aquatic resources. This research investigated the characteristics of urban runoffs and evaluate the effectiveness of the continuous deflective separation systems for stormwater best management practice. The systems were installed in the vicinity of a high-level road, an apartment complex, and the Cheonggye stream. Stormwater runoff was sampled in these sites. Biochemical oxygen demand ($BOD_5$), total suspended solid (TSS), total nitrogen (T-N), and total phosphorus (T-P) were analyzed. The removal efficiency of $BOD_5$, TSS, and T-P for the road was 10.9-81.0%, 11.7-93.4%, 0-37.5%, respectively. That of $BOD_5$, TSS, T-N, and T-P for the complex was 12.5-65.8%, 26.5-77.6%, 1.8-28.7%, and 20.0-37.5%, respectively. The abatement efficiency $BOD_5$, TSS, T-N, and T-P for the stream was 7.2-85.2%, 41.7-98.2%, 11.3-65.6%, and 2.0-71.5%, respectively. This study shows that the systems can be used to remove $BOD_5$ and TSS from urban runoffs efficiently.

• 대한토목학회논문집
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• 제12권1호
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• pp.207-217
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• 1992

본 연구에서는 기체 액체 고체의 직접접촉이 일어나는 3상 유동층 반응기를 이용하여 유입상승 유속에 의한 공극률의 변화와 생물막의 두께 및 밀도를 관측하였다. COD의 용적부하율은 반송비(r=0.2, 0.4, 0.6)로 조절하여 $201.12-1150.8g/m^3{\cdot}d$로 하였으며, 고체 매질로는 연탄재입자(평균유효입경 : 1.34 mm)와 유리비드(3 mm)를 사용하여, 매질의 차이에 따른 반응기의 효율에 대하여 비교하였다. 그 결과 반송비를 일정하게 고정시킨 경우, 연탄재 매질에 의한 생물막의 두께가 유리비드를 사용한 것보다 약 4.8배 두꺼우며, COD 제거 효율은 두 매질사이에는 변화가 거의 없으나, 암모니아성 질소의 제거에는 연탄재의 경우가 약간 높았다. 반응조내의 식종균으로는 합성폐수와 유사한 배지에서 동정 분리하여낸 토양미생물을 이용하였다 이 토양미생물은 기존의 활성슬러지균 보다 점착력과 침강성이 뛰어났다.

• 상하수도학회지
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• 제20권2호
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• pp.245-255
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• 2006

Dissolved air flotation is a solid-liquid separation system that uses fine bubbles rising from bottom to remove particles in water. In order to enhance the flotation velocity and removal efficiency of flocs in the flotation process, we tried to obtain pretreatment conditions for the optimum DAF process operation by comparing and evaluating features of actual floc formation and flotation velocity etc, according to coagulant types and conditions for flocculation mixing intensity by using PIA, PDA, and FSA. Accordingly, generating big flocs that have low density at low flocculation mixing intensity may reduce treatment efficiency. In addition, generating small flocs at high flocculation mixing intensity makes floc-bubbles smaller, which reduces flotation velocity, In this study, it was found that high flocculation mixing intensity could not remove the remaining micro-particles after flocculation, which had negative effects on treated water quality, Therefore, in order to enhance treatment efficiency in a flotation process, flocculation mixing intensity around $50sec^{-1}$ is effective.