• Membrane and Water Treatment
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• 제9권3호
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• pp.147-153
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• 2018

This study investigates the role of microbial extracellular polymeric substances (EPSs) as bioflocculants to harvest microalgae (water-microalgae separation). The EPS extracted from waste activated sludge (WAS) by heat extraction were fractionated into soluble EPS (S-EPS), loosely-bound EPS (LB-EPS) and tightly-bound EPS (TB-EPS) forms. All the EPSs facilitated the flocculation of microalgal cells from stable growth medium. Of those EPSs, the TB-EPS showed the highest flocculating activity (FA) resulting in the substantial decrease in the amount of EPS added in terms of total organic carbon (TOC) during flocculation. The FA of microalgae was improved with the increase in TB-EPS dose, however, excessive dose of TB-EPS adversely affected it due to destabilization. Both LB- and TB-EPS could be utilized for flocculating microalgae as a sustainable option to the existing chemical-based flocculants. In addition to the conventional assessments, the effectiveness of the two bioflocculants for floc forming was also confirmed using a novel assessment of lens-free shadow imaging technique (LSIT), which was firstly applied for the rapid and quantitative assessment of microalgal flocculation.

• 한국의류학회지
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• 제41권3호
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• pp.517-526
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• 2017

The biodegradation and water absorption properties of lignin/poly(vinyl alcohol) (PVA) nanofibrous webs are investigated. Lignin/PVA nanofibrous webs containing 0, 50, and 85wt% of lignin were prepared via an electrospinning process to observe the effect of the lignin concentration on the biodegradability and water absorption properties of lignin/PVA nanofibrous webs. The morphology of the materials was examined by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). To understand the wetting behavior and hydrophilic nature of the electrospun lignin/PVA nanofibrous webs, the water absorbency, contact angle, and water uptake were examined. The enzymatic degradation of lignin/PVA nanofibrous webs was investigated using laccase by measuring total organic carbon (TOC) concentration over a course of 50 days. Water drops were absorbed immediately into all of the specimens. The water uptake of lignin/PVA nanofibrous webs increased as the amount of PVA in the lignin/PVA hybrid webs increased. The enzymatic degradation experiment indicated that the inherent biodegradability of lignin was retained after its transformation into nanofibers. Our findings imply that blending these two types of polymers is promising because it can lead to the development of a new range of multifunctional materials such as antimicrobial absorbent nanotextiles based on sustainable biopolymers.

• 산업기술연구
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• 제32권A호
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• pp.95-102
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• 2012

To advance luminance efficiency of Titania at visible range, N-doped $TiO_2$ was prepared by using ammonium hydroxide as a source of nitrogen. The photoactivities of the synthesized $TiO_2$ were evaluated on the basis of degradation of humic acid in aqueous solutions with different light sources, UV-C, UV-A and fluorescent lamp. As a result, at UV-C is high efficiency $UV_{254}$ decrease and TOC removal. In this study, the best synthetic conditions of N-doped $TiO_2$ were 5.0 M of ammonium hydroxide concentration and calcination temperature of $550^{\circ}C$. The degradation rate of humic acid as an evaluation of photoactivities of the catalysts were conducted with pH variation, decrease rate of molecular absorption, removal rate of total organic carbon and fluorescece evolution for humic acid solution. XRD and SEM were applied for analysis of surface analysis of the catalysts.

• 한국물환경학회지
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• 제20권3호
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• pp.241-244
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• 2004

Radiation treatment with gamma-rays and electron-beams was used to remove polyvinyl alcohol(PVA), one of the main components of dyeing wastewater. PVA was effectively decomposed by radiation treatment, thus the removal was near 100 % at an initial PVA concentration of 44 mg/L. However, total organic carbon(TOC) removal was less than 5 % due to lower transformation of PVA to $CO_2$. This directly indicates the radiation treatment alone is not appropriate for the complete decomposition of PVA. In this sense, the improvement of biodegradability($BOD_5/COD$) of PVA by radiation treatment was studied. Both gamma-ray and electron-beam treatments significantly increased the biodegradability of PVA by transforming non-biodegradable PVA to biodegradable by-products. This suggests radiation treatment, especially electron-beam treatment that showed better improvement of biodegradability, can be used as a pre-treatment of biological degradation process of PVA.

• 한국수산과학회지
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• 제39권2호
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• pp.106-117
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• 2006

We measured the concentrations of organic matter and metallic elements (Al, Fe, Cr, Mn, Ni, Cu, Zn, As, Cd, Pb and Hg) in the surface sediments of Masan Harbor (in the southern sea, Korea) to evaluate the geochemical characters of sediment and the pollutions by organic matter and metallic elements. The mean grain size of the surface sediments in the study area ranged from $5.6{\phi}$ to $7.8{\phi}$, indicating silt sediment. The water content of the surface sediments exceeded 60% except at some stations. The contents of ignition loss (IL), total organic carbon (TOC) and total nitrogen (TN) ranged from 7.2-14.3%, 1.2-3.2%, and 0.10-0.28%, respectively. Based on the C/N ratios, the organic matter in the surface sediments of Masan Harbor may originate from terrigenous sources including fluvial inputs (mainly sewage in urban areas). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) ranged from $11.3-29.9\;mgO_2/g\;dry$ and 0.20-4.47 mgS/g dry, respectively, and low concentrations were observed near a shipping route. In addition, the concentrations of metallic elements showed large spatial variations in Masan Harbor and the distributions of metallic elements were also comparable to those of organic matter. This implies that the distributions of organic matter and metallic elements in the surface sediments of Masan Harbor are mainly controlled by biogenic matter and artificial action (mainly dredging). In addition, we calculated the enrichment facto. (EF) and geoaccumulation index (Igeo) in order to evaluate pollution by metallic elements. The enrichment of metallic elements relative to Al was three to eighteen times higher at the study sites, compared to levels in the Earth's crust except for Fe, Ni and Mn. In addition, the Igeo class indicated that the surface sediments in the study area were moderately to strongly polluted in terms of metallic elements.

• 한국습지학회지
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• 제25권4호
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• pp.221-229
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• 2023

수도권에 일 약 8백만톤의 물을 취수하여 공급하는 팔당호는 수질보전정책 시행으로 BOD(Biochemical Oxygen Demand)1.1mg/L를 달성하였으나 난분해성 물질을 포함하는 COD(Chemical Oxygen Demand) 항목은 점점 증가하는 양상을 보였다. 난분해성 유기물질의 상수원 유입은 잠재적인 BOD의 증가, 수돗물의 냄새와 맛 유발, THM(Trihalomethane) 발생 증가, 조류 증식을 일으키며 유해 난분해성 미량오염물질이 잔류할 경우 수생 환경에서 내분비 교란과 항생제 내성과 같은 현상을 유발한다. 본 연구에서는 팔당호의 난분해성 유기물질 관리를 위해 팔당호와 팔당호 상류의 점 오염원과 비점오염원의 난분해성 유기물질 유출 농도를 파악하기 위한 모니터링을 실시하였다. 지역별 난분해성 유기물질 유출 농도를 비교하고 하수처리장에서의 제거율을 파악하였다. 또한 피어슨 상관성 분석 기법을 사용해 유기물질 지표와 선행건기일수, 선·선행건기일수간 상관성 분석을 실시하였다. 하천과 팔당호의 난분해성 유기물질 농도는 유사한 양상을 보였다. 하수처리장 유출수는 하천과 팔당호보다는 높은 농도를 보였으며, 유입수와 유출수 농도의 비교 결과 하수처리장에서 난분해성 유기물질 제거율은 65.73%였다. 난분해성 유기물질 유출 농도와 선행건기일수, 선·선행건기일수 사이에서는 유의미한 상관성이 나타나지 않았다. 이는 데이터 부족으로 판단되며 장기적인 모니터링으로 데이터 축적이 필요하다 사료된다.

• 청정기술
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• 제10권1호
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• pp.37-45
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• 2004

본 연구는 섬유산업에서 많이 사용되고 있는 주요염료인 분산성, 반응성, 산성염료를 대상으로 일반적인 수질오염항목인 COD, T-N, TOC, color, SS, TDS, conductivity 등을 분석하여 각각의 염료용액의 성상을 비교 분석하였고, NF막을 투과시켰을 경우 투과 flux와 배제율이 염료용액 종류에 따라서 어떻게 다른 양상을 나타내는지를 연구하였다. 결과적으로, 염료종류별 화학적 성질 및 구조적인 차이에 의하여 염료용액의 용해도 및 유기물부하 등이 달라짐을 알 수 있었고, 특히, 분산성 염료와 반응성염료는 이들 화학적 성질의 차이가 매우 현격하게 달라서 투과 flux 감소현상과 유기물, color, 부유물 및 용존 고형물, 이온성 물질 등의 배제율이 다른 양상을 보임을 알 수 있었다. 반응성염료 용액은 분산성염료 용액에 비하여 투과 flux는 높지만, TDS의 배제율이 낮은 반면, 분산성염료 용액은 부유성 고형물 농도가 높아 투과 flux가 낮고, 유기물질의 배제율이 낮은 특성을 나타낸다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.189-193
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• 2011

유역관리 및 수질 향상을 위해 다양한 환경정책이 시행되고 있으며, 최근 수질오염총량관리제의 시행으로 인해 보다 집중적인 유역관리와 수질 향상을 위한 노력이 배가되고 있다. 이러한 노력의 일환으로 현재 환경부 국립환경과학원에서는 수질오염총량관리를 위하여 단위유역의 말단지점에서 수질 및 유량자료에 대한 정기적인 측정을 8일 간격으로 시행하고 있으며, 데이터 베이스 및 웹시스템을 통하여 자료를 공개하고 있다(이호열, 2009). 이와 같은 자료의 측정과 축적은 그 분석을 통해 수질 개선을 위한 우선 관리 대상지점의 파악 등과 같이 수질오염총량관리제의 시행과 평가를 위해 사용될 수 있을 뿐만 아니라 새로운 환경정책의 수립에도 활용될 수 있을 것으로 기대된다. 그러나 현재 소수의 연구들에서만 상기의 자료를 단순히 활용한 결과를 찾을 수 있으며, 특히 측정된 수질 및 유량자료를 분석하여 발표한 연구결과 역시 소수에 지나지 않는다(김철겸 등, 2009). 측정 자료에 대한 분석 및 이에 따른 자료의 활용성 제고를 위해서 다양한 자료 분석 기법의 개발과 적용이 절실하다. 이러한 자료 분석 기법의 개발 및 적용에 관한 연구의 일환으로 최근 패턴분류를 위해 다양한 분야에서 활용되고 있는 자기조직화 특성 지도(Self Organizing Feature Map: SOFM)를 상기의 측정 자료에 적용한 연구 결과가 보고된 바 있다(진영훈 등, 2009; 2010). 본 연구에서는 수질오염총량관리제를 위해 측정되고 있는 수질 및 유량자료를 수집하여 자료에 내재되어 있는 시 공간적 특성을 분석하고자 하였다. 영산강 유역을 대상으로 하여, 본 유역 내의 단위유역들 중 황룡_A, 지석_A, 영본_A, 영본_B, 영본_C, 영본_D의 말단지점에서 측정되고 있는 BOD (Biochemical Oxygen Demand), TOC (Total Organic Carbon), T-N (Total Nitrogen), T-P (Total Phosphorus), SS (Suspended Solids) 수질농도 및 유량자료를 대상으로 연구를 진행하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권6호
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• pp.29-36
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• 2010

Several mines including Namil, Solim and Jungbong which are located in the Gyeonggi and Kangwon province have been abandoned and closed since 1980 due to "The promotion policy of mining industry". An enormous amount of mining wastes was disposed without proper treatment, which caused soil pollution in tailing dam and ore-dressing plant areas. However, any quantitative assessment was not performed about soil and water pollution by transporting mining wastes such as acid mine drainage, mine tailing, and rocky waste. In this research, heavy metals in mining wastes were analyzed according to leaching method which used 0.1 N HCl and total solution method which used Aqua-regia to recognize the ecological effect of distance from hot spot. We sampled tailings, rocky wastes and soils around the abandoned mine. Chemical and physical parameters such as pH, electrical conductivity (EC), total organic carbon (TOC), soil texture and heavy metal concentration were analyzed. The range of soil's pH is between 4.3 and 6.4 in the tailing dam and oredressing plant area due to mining activity. Total concentrations of As, Cu, and Pb in soil near ore dressing plant area are 250.9, 249.3 and 117.2 mg/kg respectively, which are higher than any other ones near tailing dam area. Arsenic concentration in tailing dams is 31.0 mg/kg, which is also considered as heavily polluted condition comparing with the remediation required level(RRL) in "Soil environment conservation Act".