• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.728-736
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• 1996

Solid/Liquid(S/L) separation is crucial for biological treatment of animal wastewater. Liquid portion from S/L separation has less BOD-load and proper post-strip treatment can be obtained . Screen or declined sieve was normally used to separate the solid parts. For better separating efficiency a vibration and a cylindrical separator were constructed and tested. The results are summarized as follows : Solids removal efficiency and moisture content of separated solid were 15-26% and 85-88%, respectively for the vibration separator. For the cylindrical separator, solid removal efficiency and moisture content of solid were 16-39% and 86-89% , respectively. The greatest amount of drymatter was obtained when operating vibration separator with 10。 inclination and 100% vibrating power. For the cylindrical separator maximum efficiency was obtained with 40rpm and 19 inclination . The vibration and the cylindrical separator have shown 21% and 26% in BOD removal, respectively. These two types of separator were proved to be applicable methods for animal wastewater separation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.334-336
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• 2003

Recently, considerable researches have been focused to find out inexpensive sorbents. for removal of heavy metals in aquatic environments. In particular, various natural materials including geologic media have been attractive. In order to evaluate the applicability of the scoria taken from the Jeju island, Korea, to remove Zn(II) from aqueous solutions, the kinetic sorption experiments were performed in this study. The batch-type kinetic sorption tests were carried out under different conditions, such as different initial Zn(II) concentration, particle size of the scoria, and sorbate/sorbent ratio. The results indicated that the removal of Zn(II) by scoria increased with decreases in initial Zn(II) concentration, particle size of the scoria, and sorbate/sorbent ratio. However, the sorption capacity of the scoria decreased with increasing amount of the scoria. The sorption behavior of Zn(II) onto scoria seemed to be mainly controlled by cation exchange.

• 한국의류학회지
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• 제3권1호
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• pp.13-18
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• 1979

Many researches have found that the anionic surfactants are effective when the anionic soil is attached to the cotton fabrics. However, this research investigated the relationship of the super soil removal and surfactants when the anionic and cationic soil was attached to the cationic cotton fabrics. The result is that the cationic surfactants are vary effective for soil removal in the cationic cotton fabrics. The processing and nature of cationic cotton fabrics are treated and investigated as follows: Cotton fabrics are heated in the presence of ethylenimine and acetic acid dissolved in benzene to contain a significant amount of fixed nitrogen. Some polymer was formed but removal by washing with benzene and water. The optinium molor ratio of acid-to-ethylenimine seemed to be in the range 1: 10. The treated cotton fabrics dyed with acid Orange II dyes, and nitrogen content in the treated cotton fabrics were determined by the Kjeldahl method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.99-102
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• 2003

This study discusses the determination of removal time of forms with early strength development in high strength concrete. According to the results, as W/B increases by 10％, the setting time is shortened by about 2 hours. The time when compressive strength of 8 MPa is gained is about 20 hours. Bond strength between form and concrete is highest around final setting time, but decreases drastically after that. Amount of concrete sticking on the form is large before setting, but after that, it is little. The rebound value of P type schmidt hammer is measured faster by 2-3 hours than compressive strength. It is also confirmed that the removal of forms is possible when the rebound value of P type schmidt hammer is more than 34

• 한국환경보건학회지
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• 제23권4호
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• pp.121-126
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• 1997

Peroxidase as one of the organic enzyme catalyst is useful for the oxidation treatment of various aromatic compounds such as phenols. The peroxidase content of Oenanthe javanica was 24.85 unit/g-fw in leaf, 5.74 unit/g-fw in stem, and 34.69 unit/g-fw in root respectively. The crude peroxidase extracted from Oenanthe javanka can be kept under low temperature (-70$\circ$C) condition for 6 months with the maximum 1% activity reduction. The optimum conditions of removal for 100 ppm phenol was pH 6, hydrogen peroxide 3.5 mM, peroxidase activity 8 unit/ml, temperature 20$\circ$C respectively. In the wide range of concentration from 50 ppm to 750 ppm phenol reveals average 54% removal rate under the same peroxidase activity (8 unit/ml) and different amount of hydrogen peroxide proportional to phenol concentration. Especially at the concentration of 100 ppm the maximum phenol removal rate was 72%.

• Environmental Engineering Research
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• 제10권1호
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• pp.1-6
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• 2005

Hexavalent chromium in aqueous solutions was successfully removed via sorption and reduction in the presence of waste leaves. Cr(VI) removal followed a first-order reaction, and removal rates were proportional to the amount of waste leaves used in the tests. Most of Cr(VI) were removed via sorption in early stages of the tests, but the reduction reaction played a significant role in Cr(VI) removal later. Solution pHs were continuously decreased due to the microbial activity, which was induced from the microorganisms attached on waste leaves. The decreased solution pHs further enhanced the sorption and reduction of Cr(VI). To characterize the microorganisms found in the tests, a denaturing gradient gel electrophoresis (DGGE) method was used. The majority of microorganisms were composed of Bacillus sp. which can reduce Cr(VI). Thus, waste leaves can be effective reactive media for the treatment of Cr(VI) in the subsurface.

• 자원리싸이클링
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• 제31권4호
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• pp.49-55
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• 2022

본 연구에서는 인덕션 탑플레이트(induction top plate) 소재로 사용된 후 폐기되는 사용 후 Li₂O-Al₂O₃-SiO₂계 결정화 유리를 활용하여 중금속 용액 내 존재하는 중금속(Pb, Cd, Cr⁶⁺, Hg) 이온들의 제거 실험을 진행하였다. 중금속 흡착제로 사용된 흡착제의 양, 흡착 반응 시간, 초기 중금속 원소의 농도, 초기 용액의 pH 등의 반응 조건에 따른 중금속 제거 효율의 변화를 조사하였다. 사용 후 LAS 첨가량이 증가할수록 중금속 제거 효율이 상승하였다. 흡착 반응 시간은 흡착 특성에 큰 영향을 미치는 것으로 확인되었으며, 모든 중금속 원소들의 제거 효율이 상승하였다. 특히 반응 시간에 따라서 Cd의 경우 흡착제거 효율이 크게 개선되었다. 초기 중금속 용액 농도는 중금속 제거 효율에 영향을 미치지 않았다. 중금속 용액의 pH는 중금속 제거 효율에 영향을 미쳤는데, Cd의 경우 pH증가에 따라 중금속 제거 효율이 증가하였으며, Pb, Cr⁶⁺는 감소하였다. Hg는 pH가 흡착 특성에 큰 영향을 미치지 않았다.

• 한국환경과학회지
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• 제21권8호
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• pp.901-907
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• 2012

The objective of this study was to evaluate bacteria removal ability of the metallic silver which was baked silver ion impregnated ceramic filter at heating condition. Silver leaking from baked ceramic filter was tested to sustain bacteria removal for a long time. Silver impregnated ceramic filter could remove E. coli completely at $10^{12}$ MPN/100ml to $10^{13}$ MPN/100ml of influent. However, ceramic filter without silver did not remove E. coli completely under the same condition. After baking, the silver impregnated ceramic filter almost didn't leak out the silver ion from filter. Photo of TEM (Transmission Electron Microscopy) showed that absorbed silver ions remained in ceramic filter after baking process and most of silver were less than 10 nm. According to the increase in the amount of silver in the ceramic filter, removal efficiencies of E. coli were increased but turbidity removal was decreased. It can be accounted that increased removal efficiency of E. coli was from disinfection of silver that is in the ceramic filter. Simulated concentrations of bacteria agree well with the observed experimental effluent concentration data. Moreover, first-order decay coefficients increased to 0.0034/min after silver was added in the ceramic filter. Increase of first-order decay coefficient proves that silver-added ceramic filter can remove bacteria easily.

• 대한화학회지
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• 제60권5호
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• pp.317-320
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• 2016

Efficient copper removal from water was achieved by using surface modified silica spheres with 3-mercaptopropyltrimethoxysilane (MPTMS) using base catalyst. The surface modification of silica spheres was performed by hydrolysis and condensation reactions of the MPTMS. The characteristic infrared absorption peaks at 2929, 1454, and 1343 cm⁻¹ represent the −CH₂ stretching vibration, asymmetric deformation, and deformation, respectively. The absorption peaks at 2580 and 693 cm⁻¹ corresponding the −SH stretching vibration and the C-S stretching vibration indicate the incorporation of MPTMS to the surface of silica spheres. Field emission scanning electron microscope (FESEM) image of the surface modified silica sphere (SMSS) shows nano-particles of MPTMS on the surface of silica spheres. High concentration of copper solution (1000 ppm) was used to test the copper removal efficiency and uptake capacity. The FESEM image of SMSS treated with the copper solution shows large number of copper lumps on the surface of SMSS. The copper concentration drastically decreased with increasing the amount of SMSS. The residual copper concentrations were analyzed using inductively coupled plasma mass spectrometer. The copper removal efficiency and uptake capacity with 1000 ppm of copper solution were 99.99 % and 125 mg/g, respectively.

• The Korean Journal of Ecology
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• 제18권2호
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• pp.219-230
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• 1995

Although many studies of nutrient cycling in forest ecosystems have reported that clearcutting creates increased organic matter decomposition and nitrogen (N) mineralization in soils, little is known about the change of these factors following various levels of canopy removal. A series of experimental plots with four levels of canopy cover, i.e., clearcut, 25％, 75％, and uncut, was established in northern red oak (Quercus rubra L.) stands in northern Lover Michigan, U.S.A. I examined decomposition of cellulose filter papers and N mineralization using an in situ soil incubation technique in the top 15cm of mineral soil during the second growing season (1992, May-October) following stand manipulation. Mass loss from cellulose filter papers was more rapid in the canopy removal treatments than in the uncut treatment. similarly, net N mineralization was significantly greater in the canopy removal treatments than in the uncut treatment. There was no significant difference in net N mineralization rates among the three levels of canopy removal. Net N mineralization for the growing season was 58 kg/ha for the clearcut, 54 kg/ha for the 25％ canopy cover, 51 kg/ha for the 75％ canopy cover, and 22 kg/ha for the uncut treatment. These results indicated that even only small amounts of canopy removal (leaving 75％ canopy cover) let to substantial increases of cellulose decomposition and the amount of available soil nitrogen.