• 한국환경과학회지
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• 제22권9호
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• pp.1153-1160
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• 2013

While a range of natural organic matter (NOM) types can generate high levels of disinfection by-products (DBPs) after chlorination, there is little understanding of which specific compounds act as precursors. Use of eight model compounds allows linking of explicit properties to treatability and DBP formation potential (DBPFP). The removal of model compounds by various treatment processes and their haloacetic acid formation potential (HAAFP) before and after treatment were recorded. The model compounds comprised a range of hydrophobic (HPO) and hydrophilic (HPI) neutral and anionic compounds. On the treatment processes, an ozone oxidation process was moderate for control of model compounds, while the HPO-neutral compound was most treatable with activated carbon process. Biodegradation was successful in removing amino acids, while coagulation and ion exchange process had little effect on neutral molecules. Although compared with the HPO compounds the HPI compounds had low HAAFP the ozone oxidation and biodegradation were capable of increasing their HAAFP. In situations where neutral or HPI molecules have high DBPFP additional treatments may be required to remove recalcitrant NOM and control DBPs.

• 상하수도학회지
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• 제22권4호
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• pp.467-473
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• 2008

Natural organic matter (NOM) removal by physico-chemical adsorption and biological oxidation was investigated in five slow sand filters with different media depths. Non-purgeable dissolved organic carbon(NPDOC) and $UV_{254}$ absorbance were measured to evaluate the characteristics of NOM removal at different filter depths. Removal efficiency of NOM was in the range of 10-40% throughout the operation time. At start-up of the filters packed with clean sand media, NOM was probably removed by physico-chemical adsorption on the surface of sand through the overall layer of filter bed. However, when Schumutzdecke layer was built up after 30 days operation, the major portion of NPDOC was removed by biological oxidation and/or bio-sorption in lower depth above 50 mm. NOM removal rate in the upper 50 mm filter bed was $0.82hr^{-1}$. It was about 20 times of the rate($0.04hr^{-1}$) in the deeper filter bed. Small portion of NPDOC could be removed in the deeper filter bed by both bio-sorption and biodegradation. SEM analysis and VSS measurement clearly showed the growth of biofilm in the deeper filter bed below 500 mm, which possibly played an important role in the NOM removal by biological activity besides the physco-chemical adsorption mechanism

• 대한환경공학회지
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• 제30권4호
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• pp.423-429
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• 2008

유기물과 무기물이 함께 오염되어 있는 합성 폐수처리에 대한 망간첨착활성탄(Mn-AC)의 적용성을 연구하였다. 유기물과 무기물의 대표물질로 페놀과 3가 비소를 각각 선정하였다. 산성조건에서 Mn-AC의 안정성을 평가하기 위해, 용액의 pH를 2, 3 및 4로 달리하여 시간경과에 따른 용존망간의 용출능을 평가하였을 때, pH 3보다 낮은 조건에서는 Mn-AC의 안정성이 떨어졌지만, pH 4에서는 반응시간동안 용출되는 망간의 농도는 무시할 수 있는 정도였다. 이러한 안정성 실험결과 Mn-AC는 pH 4 이상의 일반폐수 처리에 사용할 수 있음을 알 수 있었다. AC와 비교하였을 때, 망간첨착에 의한 비표면적 감소로 인해 망간첨착활성탄의 페놀제거속도 및 페놀 흡착능은 일부 감소하였다. 페놀 농도 변화에 따른 등온흡착결과 Mn-AC의 최대흡착량은 AC의 75%에 해당하였다. 산성영역의 pH에서는 Mn-AC에 의한 3가 비소 산화효율이 AC보다 높았지만 pH 7 이상에서는 반대 경향을 나타내었다. 본 연구를 통하여 Mn-AC를 페놀과 3가 비소의 동시처리에 적용할 수 있음을 알 수 있었다.

• 한국물환경학회지
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• 제23권1호
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• pp.72-80
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• 2007

The seasonal variation of organic matter and the oxidation efficiency of BOD and COD were investigated in several reservoirs and rivers located in the Han River system from March 2005 to April 2006. The concentrations of TOC in the Dong River, the Myeongjicheon stream and the Han-River varied with season. Mean concentration of TOC in the lotic environment ranged from 1.9 to 6.8 mgC/L. Oxidation efficiencies calculated from carbon were approximately 12.6 to 27.1% for BOD and 27.2 to 75.0% for COD, respectively. DOC to TOC ratio in the rivers ranged from 64.3 to 79.0%. Epilimnetic TOC concentrations in two clear and deep lakes (Lake Soyang and Paro) ranged from 2.0 to 2.8 mgC/L. TOC concentrations in the lower three dams (Lake Chunchon, Uiam, and Chungpyung) were relatively high that ranged from 3.4 to 3.7 mgC/L.Oxidation efficiencies in five lakes ranged from 10.6 to 17.2% for BOD and 32.6 to 49.5% for COD, respectively. The range of DOC to TOC in Lake Soyang and Paro was approximately 69. 0 to 73.4%. The ratios of lower three dams ranged from 48.2 to 62.3%. The differences among the lakes seemed to be asociated with limnological and hydrological characteristics of the lakes.

• 한국해양학회지:바다
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• 제10권3호
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• pp.145-153
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• 2005

산소가 고갈된 혐기성 환경의 유기물 분해 및 물질순환에서 철 환원반응의 생태/환경적 중요성에 대해 고찰하였다. 다양한 해양환경에서 유기물 분해 시 철 환원이 차지하는 중요성은 미약한 수준에서 거의 $100\%$에 이르기까지 그 범위가 극단적으로 다양하게 나타났다. 일반적으로 철 환원은 Fe(III)의 농도가 높은 곳에서 황산염 환원보다 중요한 유기물 분해 경로로 나타나, 유기물 분해에서 철 환원의 중요성은 철 환원세균이 이용 가능한 Fe(III)의 공급정도에 의해 결정되는 것으로 인식되었다. 산소공급이 미약한 연안혐기성 퇴적토 내에서 Fe(III)의 공급은: (1)조석에 의한 퇴적물 내 공극수의 교환(tidal flushing): (2)저서동물에 의한 생물교란: (3)식생의 유무에 따른 퇴적물의 산화/환원 상태의 변화 등에 의해 주로 영향을 받는 것으로 나타났다 철 환원세균에 의한 유기물 분해 및 다양한 금속원소의 전환기능을 이용한 특정 유기오염원과 금속오염원의 생물정화는 우리나라와 같이 부영양화된 연안생태환경의 개선 및 독성 유t무기 오염원의 생물정화 등 연안역의 환경친화적 관리가 절실히 요구되는 환경에서 생태/환경공학 분야의 유용한 해결수단으로 간주된다.

• 상하수도학회지
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• 제25권6호
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• pp.861-867
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• 2011

Wastewater from crude oil reserve base usually contains large amount of non-biodegradable contaminants. The conventional wastewater treatment progress can hardly meet the regulation of wastewater effluent quality. This study investigated the removal of non-biodegradable organic contaminants in wastewater from crude oil reserve base using a pulse UV treatment. The modified process incorporating pulse UV process was set up to treat the wastewater from crude oil reserve base. The treatment process is composed with coagulation and flocculation, micro-bubble flotation, sand filter, pulse UV system, and GAC filter. The results show CODMn was effectively removed by the process with pulse UV system and it can meet the wastewater effluent regulation. The single effect of pulse UV process in CODMn removal was not significant(9~15% based on sand filtered effluent), however with the subsequent activated carbon filter the removal ratio CODMn was increased up to 28% compared to the process without pulse UV syetem.

• 한국환경보건학회지
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• 제23권3호
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• pp.121-129
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• 1997

This study was performed to delineate the removal phenol in solutions using of ozone, ozone/$H_2O_2$ and ozone/GAC. The disinfection by-product of phenol by ozonation, hydroquinone, was analyzed and it's control process was investigated. The followings are the conclusions that were derived from this study. 1. The removal efficiency of phenol by ozonation was 58.37%, 48.34%, 42.15%, and 35.41% which the initial concentration of phenol was 5 mg/l, 10 mg/l, 15 mg/l, and 20 mg/l, respectively. 2. The removal efficiency of phenol by ozonation was 42.95% at pH 4.0 and 69.39% at pH 10, respectively. The removal efficiencies were gradually increased, as pH values were increased. 3. With the ozone/$H_2O_2$ combined system, the removal efficiency of phenol was 72.87%. It showed a more complete degradation of phenol with ozone/$H_2O_2$ compared with ozone alone. 4. When ozonation was followed by filtration on GAC, phenol was completely removed. 5. Oxidation, if carried to completion, truly destroys the organic compounds, converting them to carbon dioxide. Unless reaction completely processed, disinfection by-products would be produced. To remove them, ozone/GAC treatment was used. The results showed that disinfection by-product of phenol by ozonation, hydroquinone, was completely removed. These results suggested that ozone/GAC should also be an appropriate way to remove phenol and its by-product.

• Membrane and Water Treatment
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• 제8권6호
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• pp.517-528
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• 2017

This study evaluates the performance of membrane bioreactor (MBR) coupled with a modified walnut shell granular activated carbon (WSGAC) for tannery wastewater treatment. For this purpose, a pilot with overall volume of 80L and 12 hours hydraulic retention time (HRT) is operated in three scenarios. Here, the chemical oxidation demand (COD) of wastewater is reduced more than 98% in both C:N ratios of 13 (S1) and 6.5 (S2). This performance also remains intact when alkalinity depletes and pH reduces below 6 (S3). The ammonium removal ranges between 99% (S2) and 70% (S3). The reliability of system in different operating conditions is due to high solids retention time and larger flocs formation in MBR. The average breakthrough periods of WSGAC are determined between 15 minutes (S2) and 25 minutes (S1). In this period, the overall nitrate removal of MBR-WSGAC exceeds 95%. It is also realized that adding no chemicals for alkalinity stabilization and consequently pH reduction of MBR effluent (S3) can slightly lengthen the breakthrough from 15 to 20 minutes. Consequently, MBR can successfully remove the organic content of tannery wastewater even in adverse operational conditions and provide proper influent for WSGAC.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.28-51
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• 2018

Graphitic carbon nitride ($g-C_3N_4$) as a fascinating visible light active semiconductor photocatalyst has medium band gap, non-toxic nature, stable chemical structure and high thermal stability. Recently, intensive researches are focused on photocatalytic activity of $g-C_3N_4$ for wastewater treatment. This review demonstrates latest progress in fabrication of graphitic carbon nitride $C_3N_4$ incorporated nanocomposite to explore photocatalytic ability for water purification. The $g-C_3N_4$-based nanocomposites were categorized as $g-C_3N_4$ metal-free nanocomposite, noble metals/$g-C_3N_4$ heterojunction, non-metal doped $g-C_3N_4$, transition and post transition metal based $g-C_3N_4$ nanocomposite. Apart from fabrication methods, we emphasized on elaborating the mechanism of activity enhancement during photocatalytic process.

• Korean Chemical Engineering Research
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• 제62권3호
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• pp.233-237
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• 2024

본 연구는 유/무기 나노복합체를 이용한 PAN계 탄소섬유 토우(PAN-based carbon fibers tow) 기반의 유연 전극 제작 및 이를 활용한 비효소 전기화학 센서 개발에 대한 것으로, 전도성 고분자 polyaniline (PANI)와 금속 산화물 CuO을 유/무기 나노복합체 소재로 사용하였으며 글루코스를 전기화학 센서 타겟으로 적용하였다. 전극 제작을 위해 시판된 CFT는 열처리를 통한 사이징(sizing) 제거와 전기화학적 산화에 의한 표면 활성화의 전처리 공정을 거쳐 사용되었다. 유/무기 나노복합체는 전기화학적 중합 및 증착법을 통해 전처리된 CFT 표면 위에 순차적으로 합성되어 최종 CFT/PANI/CuO NPs 전극이 제작되었다. CFT/PANI/CuO NPs 전극의 전기화학적 특성 및 센싱 성능은 시간대전류법와 순환전압 전류법, 전기화학 임피던스 분광법을 이용하여 분석되었다. CFT/PANI/CuO NPs 전극은 전도성 고분자과 금속 산화물의 접목에 의해 전기 전도도 향상 및 우수한 전자 전달, 감응시간 단축, 비표면적 증가 등 개선된 전기화학적 특성과 증가된 감도, 넓은 선형 농도 구간, 높은 선택도 등 향상된 글루코스 센싱 성능을 보였다.