• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.122-127
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• 2006

The aim of this study was to investigate the characteristics of membrane fouling caused by soluble organic materials in a membrane bioreactor process. For the removal of filterable organic materials (FOC) smaller than $1{\mu}m$, coagulants and activated carbon were added. A membrane bioreactor using a submerged $17{\mu}m$ metal sieve was operated in laboratory scale to examine the possibility of membrane fouling control. As the dosage of GAC and coagulant increased, the residual FOC concentration decreased and the permeate flow rate increased markedly. The permeate flux increased with an increased PACl addition at the range from 0 to 50 mg/l. At coagulant dosage of 27mg/l, the removal of FOC was about 46% and the flux increased to 3.5 times compared to the case without PACl addition. The permeate flux increased gradually with an increase in GAC dosage. At GAC dosage of 50mg/L, the permeate flux was about 2 times higher compared that for raw water. The particle in the range of $0.1{\sim}1.0{\mu}m$ were removed effectively by the addition of GAC and coagulant. Higher osage of GAC and coagulant, led to higher removal of FOC. A different set of experiments was also performed to investigate the effect of pretreatment on the permeation ability of MBR system using the metal sieve membrane. After 40 hours of operation, the permeate flux was about 1,000 ($L/m^2-hr$), which is 20 times higher compared to the results in literature. It is likely that combined pretreatment using coagulant and activated carbon was the most effective to resolve membrane fouling problems. Moreover, the continuous operations could be successful by applying this pretreatment method.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.2777-2783
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• 2015

Background: Nestin is associated with neoplastic transformation. However, the mechanisms by which nestin contributes regarding invasion and malignancy of gastric adenocarcinoma (GAC) remain unknown. Recent studies have shown that the epithelial-mesenchymal transition (EMT) is important in invasion and migration of cancer cells. In the present study, we aimed to investigate the expression of nestin and its correlation with EMT-related proteins in GAC. Materials and Methods: The expression of nestin and EMT-related proteins was examined in GAC specimens and cell lines by immunohistochemistry and Western blotting. Clinicopathological features and survival outcomes were retrospectively analyzed. Results: Positive nestin immunostaining was most obviously detected in the cytoplasm, nucleus or both cytoplasm and nucleus of tumor cells in 19.2% (24/125) of GAC tissues, which was significantly higher than that in normal gastric mucosa tissues (1.7%, 1/60) (p=0.001). Nestin expression was closely related to several clinicopathological factors and EMT-related proteins (E-cadherin, vimentin and Snail) and displayed a poor prognosis. Interestingly, simultaneous cytoplasmic and nuclear nestin expression correlated with EMT-related proteins (E-cadherin, vimentin and Snail) (p<0.05) and lymph node metastasis (p=0.041) and a shorter survival time (p<0.05), but this was not the case with cytoplasmic or nuclear nestin expression. Conclusions: Nestin, particularly expression in both cytoplasm and nucleus, might be involved in regulating EMT and malignant progression in GAC, with potential as an unfavorable indicator in tumor diagnosis and a target for clinical therapy.

• Journal of Korean Society on Water Environment
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• v.18 no.4
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• pp.355-363
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• 2002

A demonstration plant was carried out to investigate the removal efficiency of $NH_3-N$ and $KMnO_4$ consumption depending on the existence of pre-chlorination for the ozonation and activated carbon process in the S water treatment plant which is located at the middle of Keum River. The averge removal efficiency of $KMnO_4$ consumption for $O_3/GAC$ processes with pre-chlorination and $O_3/BAC$ processes without pre-chlorination were 48.6% and 50% respectively. It is similar to removal effect of $KMnO_4$ consumption for GAC and BAC process depending on the existence of pre-chlorination. Otherwise, the removal of THMFP for GAC and BAC process was 58% and 68% respectively. $NH_3-N$ was not almost removed by sand filter and ozonation, but the average removal efficiency in the BAC process was about 31%. Especially, $NH_3-N$ was not almost removed by $O_3/BAC$ processes at the low temperature (below $$10^{\circ}C$$) in the winter season, $O_3/BAC$ processes have the advantage of removal of organic substance when it is compared to pre -chlorination followed by $O_3/GAC$ processes. Pre-chlorination followed by $O_3/GAC$ processes were required to remove $NH_3-N$ in the winter season because the removal of $NH_3-N$ was almost ineffective by $O_3/BAC$ process.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.206-212
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• 2013

This study accessed the adsorption characteristics of the 11 perfluorinated compounds (PFCs) on coal-based granular activated carbon (GAC). The breakthrough appeared first for PFODA and sequentially for PFHDA, PFTeDA, PFTDA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, PFOS, and PFHpA. The maximum adsorption capacity (X/M) for the 11 PFCs with apparent breakthrough points ranged from 2.43 ${\mu}g/g$ (for PFODA) to 64.5 ${\mu}g/g$ (for PFHpA). Carbon usage rate (CUR) for PFODA was 0.291 g/day, 11.2 times higher than that for PFHpA (0.026 g/day). The X/M values for the 11 PFCs were fitted well with a linear regression ($r^2$ = 0.89) by their molecular weight (chain length).

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.75-82
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• 2007

Washed wastewater generated from the intermittent cleaning process of the three tunnel sites located in the Seoul area showed high concentrations of SS, $COD_{Cr}$, T-N, $NH_3-N$, $NO_3-N$, Zn, Cu, Cr(+6), Mn, Mg, Phenol, $CN^-$ and E-Coli based on the water quality analysis. These characteristics of the deteriorative wastewater depend on the sampling method, cleaning frequency, released amount of washing water, inner material of tunnel wall, traffic volume, and type of drainage systems. Gravitational separation experiment of SS with collected tunnel wastewater showed considerable removal of pollutants such as 80% of $COD_{Cr}$, 30% of T-N and 90% of T-P simultaneously. GAC isotherm test was conducted to remove dissolved portion of the pollutants, and resulted in high removal efficiencies above 80% of $COD_{Cr}$, T-N, Zn, Cu, Mn, Phenol, CN in the experimental condition of GAC dosage of $50g/1/{\ell}$.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.237-245
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• 2017

This study was aimed at investigating effluent water quality and proposing reuse possibilities for 12 sewage treatment plants discharged more than $5,000m^3/day$ in order to recycle the sewage treatment plant effluent of Jeollabuk-do effectively. Additionally, a laboratory scale test for reprocessing water discharge was performed. Categories of reclaimed sewage water reuse were divided into 7 topics and analyzed a total of 28 items including 16 heavy metals based on water quality standard. As a results, color, BOD, TN, chloride and Electrical Conductivity (EC) exceeded reused water quality standard. In particular, color and TN exceeded in 8 and 5 sewage treatment plants, respectively. The value of chloride and EC were high in sewage treatment plants including the food and industrial wastewater. At 4 sewage treatment plants were possible to reuse without re-treatment. The laboratory scale test was conducted to SandFilter (SF)-Granular Activated Carbon (GAC)-MicroFiltraion (MF)-Reverse Osmosis (RO). Both the removal efficiencies and economic feasibility of total E. coli., color and Suspended Solid (SS) suited in case using the SF-GAC treatment method. The removal of chloride and EC had little effect in the case of SF-GAC-MF system, but RO showed over 90% of removal efficiency. After using SF-GAC process only, the concentration of $UV_{254}$ decreased sharply from 0.3651 /cm to 0.0306 /cm and it showed over 92% of removal efficiency rate. In conclusion, for the effective reuse of sewage discharged water, water quality and the surrounding terrain of treatment plants should be all taken into account. If it needed for the reprocessing, both the selection for treatment and economic combination treatment methods will have to be considered.

• 수도
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• v.23 no.6 s.81
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• pp.30-35
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• 1996

조류의 성장에 기인하여 대청호로부터 발생된 이취미와 천연유기물질의 제거를 위해 활성탄 흡착에 관한 파일롯 플랜트연구를 수행하였다. 대청호원수의 용존유기물질 농도는 1.5-3.5mg/1으로 나타났고, 이취미를 유발시킨 주 성분인 Geosmin농도는 가을에 60ng/1 이상이 검출되었다. 이는 8월말부터 발생하기 시작하여 10월말 까지 지속되었다. 이는 8월말부터 발생하기 시작하여 10월말 까지 지속되었다. 한국수자원공사 대청수도내 파일롯 플랜트는 재래식정수처리 시스템에 오존산화공정, 4개의 입상활성탄 흡착탑으로 구성되었다. 공탑체류시간(EBCT) 15분 이상에서, 이취미 발생기간동안 GAC 3지와 4지에서 이취미는 완전히 제거되었다. 활성탄 원료 종류별 DOC제거를 위한 파일롯연구에서 석탄계 활성탄으로 충진한 GAC 3지와 4지는 운전 3개월 후에 파괴되기 시작하였고, 이 후 4개월의 운전동안 약 40-50%의 일정한 제거효율을 보여주었다. 야자계 활성탄으로 충진된 GAC 2지는 2개월의 운전 후에 완전히 파괴되었다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2000.05a
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• pp.134-139
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• 2000

Crab shell의 중금속 제거 가능성과 그 효율을 검토하기 위하여 chemical sorbent인 cation exchange resin(CER), zeolite, granular activated carbon(GAC), powdered activated carbon(PAC)의 중금속 제거능을 비교한 결과 다음과 같은 결론을 도출할 수 있었다. 1) 0.1 mM～l.0 mM의 초기 중금속 농도에서 중금속 제거량에 미치는 영향을 비교해 보았을 때 중금속 제거의 평형에 도달하는 시간은 농도가 높을수록 오래 걸렸으며 단위 흡착제 질량당 중금속 제거량은 초기 중금속 농도가 높을수록 증가하였다. 특히 구리 이온 제거 실험에서는 낮은 농도에서 crab shell의 구리 이온 제거량이 CER의 경우보다 조금 떨어지는 경향을 보였으나, 대부분의 중금속 제거에 있어서는 crab shell이 다른 chemical sorbent에 비해 뛰어난 중금속 제거능력을 보였다. 2) 흡착 등온 모델에 적용해 보았을 때, 단위 흡착제 질량당 중금속 최대 흡착량이 crab shell > CER > zeolite > PAC =GAC의 순으로, 모든 중금속 제거 실험에서 crab shell이 가장 뛰어난 것으로 나타났다. 실제 폐수처리 공정에서는 GAC나 PAC가 많이 이용되고 있는데, 수중의 중금속을 보다 효율적이고 경제적으로 처리할 수 있는 crab shell을 폐수처리 공정에 응용할 수 있는 방안을 검토할 필요성이 있을 것으로 판단된다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.213-216
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• 2008

2차원 전극의 RhB 분해 성능은 Pt(+)-Pt(-) > Pt(+)-Sus(-) > Sus(+)-Sus(-) 전극의 순으로 나타났다. 3차원 전극은 Pt-ACF-Pt 전극만 2차원 전극보다 초기 반응속도가 낮고 최종 RhB농도가 높은 것으로 나타났으나 다른 전극은 충전물 종류에 관계 없이 2차원 전극보다 초기 반응속도가 높은 것으로 나타났다. 음극의 종류에 관계없이 3차원 전극의 충전물에 따른 RhB 분해는 GAC > Nonwoven fabric fiber > ACF로 나타났다. GAC 충전량이 50 g 이상에서 RhB 분해속도는 거의 유사한 것으로 나타났으나 전력을 고려한 단위 W당 시간당 RhB 농도 감소를 나타내었다. 그림에서 보듯이 최적 GAC 충전량은 50 g로 사료되었다. 최적 전류는 2.5 A로 사료되었다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.131-133
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• 2007

본 연구는 톨루엔이 흡착된 활성탄에 따라 MW를 적용함으로써 열적 탈착을 유도하여 활성탄을 재생하는데 그 목적을 두었다. 따라서 MW를 활성탄에 적용함으로써 발생하는 특성을 다음과 같이 분석하였다. 100W, 500W출력의 MW를 GAC에 적용 시 저출력인 100W에서는 방전 현상이 일어나지 않았으며, MW의 출력이 높아질수록 활성탄의 급속한 온도상승과 그에 따른 빈번한 방전이 발생하였다. 이는 출력이 높아 온도상승이 급속해지면 GAC에 흡착된 VOCs를 탈착 시에는 유리하나 높은 온도와 더불어 방전으로 인해 톨루엔의 분해가능성이 높아져 2차적인 오염물질을 배출할 수 있는 문제점을 알 수 있었다. 따라서 100W의 출력에서도 GAC에 흡착 된 톨루엔을 탈착시키기에 충분한 온도 상승과 방전 줄임 현상을 알 수 있었다. 또한 100W의 출력에서 98%의 탈착 효율을 얻을 수 있었으며 GC/MS 분석결과 탈착가스의 성분에서 95.6%의 톨루엔을 검출 할 수 있었다.