• 대한환경공학회지
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• 제34권9호
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• pp.597-603
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• 2012

본 연구에서는 보의 설치가 하천 퇴적물에 미치는 영향을 알아보고자 남한강 하류에 설치된 강천보, 여주보, 이포보에 대하여 보의 영향을 잘 대표할 수 있다고 생각되는 9개 지점을 선정해 퇴적물 분석을 진행하였다. 채취한 퇴적물의 물리적, 화학적 특성을 분석하기 위해 입도, 함수율, 완전연소가능량, COD, TOC, TP, SRP, TN 항목을 선정하여 분석하였다. 분석결과 퇴적물의 입도 분포는 전 구간에 걸쳐 같은 Sandy loam의 토양분류를 나타내어 준설이 퇴적물의 입도 분포에 영향을 주었다고 판단된다. 입도, 함수율, 완전연소가능량, COD, TOC, TP, SRP, TN 항목에서 보 설치지점의 상류 농도가 하류보다 높게 나타나는 것으로 보아 남한강 하류 유역에 설치된 보가 퇴적물 흐름에 영향을 미쳐 보의 상부에 퇴적양상을 나타내었다고 생각한다. 하지만 SRP 및 C/N 비율 분석 결과에서는 지역에 따른 퇴적물 특성의 차이가 크지 않고, 퇴적물의 유기물 기원 분석의 경우에는 과거 퇴적물의 특성이 나타나는 점으로부터 연구가 수행된 시점에서는 보의 설치가 퇴적물의 특성에 미치는 영향이 크지 않다고 판단된다. 하지만, 남한강 수계에 설치된 보는 강우에 의해 외부에서 유입되는 토사의 이동 및 퇴적에 영향을 줄 수 있고, 이는 수층으로의 오염물질의 확산 및 재부유를 발생시켜 수질 및 수생태계에 영향을 미칠 수 있으므로 보 설치구간 퇴적물의 물리적 화학적 특성 변화에 대한 지속적인 모니터링이 필요하다고 생각한다.

• 한국미생물·생명공학회지
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• 제27권4호
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• pp.311-319
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• 1999

Leaves of Aloe vera Linne and bloods of domestic animal were composted in a soild state fermentation reactor (SSFR) by using microbial additive including a bulking and moisture controlling agent. From solid-culture of microbial additive, 10 species of bacteria and 10 species of fungi were isolated and, their enzyme activities including amylase, carboxy methyl cellulase CMCase, lipase and protease were detected. Optimum fermentation conditions of Aloe leaves and domestic animal bloods in SSFR were obtained from the studies of response surface analysis employing microbial additive content, initial moisture content, and fermentation temperature as the independent variables. The optimum conditions for SSFR using Aloe leaves were obtained at 9.45$\pm$73%(w/w) of microbial additives, 62.73$\pm$4.54%(w/w) of initial moisture content and 55.32$\pm$3.14$^{\circ}C$ of fermentation temperature while those for SSFR using domestic animal bloods were obtained at 10.25$\pm$2.04%, 58.68$\pm$4.97% and 57.85$\pm$5.$65^{\circ}C$, respectively. Composting process in SSFR was initially proceeded through fermentation and solid materials were decomposed within 24 hours by maintaining higher moisture level, and maturing and drying steps are followed later. After the fermentation step, the concentrations of solid phase inorganic components were increased while that of organic components were decreased. Also, concentrations of total organic carbon(TOC), peptides, amino acids, polysaccharides, and low fatty acids in water extracts were increased. As fermentation in composting process depends on initial C/N ratios in water extracts of two samples were increased because of increased water-soluble TOC. From these results, it was revealed that solid state fermentation reactor using microbial additives can be used in composting process of organic wastes with broad C/N ratio.

• 한국대기환경학회지
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• 제34권3호
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• pp.457-468
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• 2018

To improve understanding of the physico-chemical characteristics of aerosols in the national park and comparing the air pollution between national park and the urban area nearby national park, the aerosol characterization study was conducted in Bukhansan National Park, Seoul, from July through September 2017. Semi-continuous measurements of $PM_{2.5}$ using PILS (Particle Into Liquid System) coupled with IC (Ion Chromatography) and TOC (Total Organic Carbon) analyzer allowed quantification of concentrations of major ionic species($Cl^-$, $SO_4{^{2-}}$, $NO_3{^-}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg{^{2+}}$ and $Ca{^{2+}}$) and water soluble organic carbon (WSOC) with 30-minute time resolution. The total mass concentration of $PM_{2.5}$ was measured by T640 (Teledyne) with 5-minute time resolution. The black carbon (BC) and ozone were measured with a minute time resolution. The timeline of aerosol chemical compositions reveals a strong influence from urban area (Seoul) at the site in Bukhansan National Park. Inorganic aerosol composition was observed to be dominated by ammoniated sulfate at most times with ranging from $0.1{\sim}32.6{\mu}g/m^3$ (6.5~76.1% of total mass of $PM_{2.5}$). The concentration of ammonium nitrate, a potential indicator of the presence of local source, ranged from below detection limits to $20{\mu}g/m^3$ and was observed to be highest during times of maximum local urban (Seoul) impact. The total mass of $PM_{2.5}$ in Bukhansan National Park was observed to be 10~23% lower than the total mass of $PM_{2.5}$ in urban area (Gireum-dong and Bulgwang-dong, Seoul). In general, ozone concentration in Bukhansan National Park was observed to be similar or higher than urban sites in Seoul, suggesting additional biogenic VOCs with $NO_x$ from vehicle emission were to be precursors for ozone formation in Bukhansan National Park.

• 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.

• 한국입자에어로졸학회지
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• 제9권3호
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• pp.187-197
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• 2013

To understand the characteristics of organic aerosol(OA) at the background atmosphere of Korea, an observation of atmospheric PM10 was conducted at a Global Atmospheric Watch(GAW) station operated by the Korean Meteorological Administration at Anmyon Island during 2010. Various organic compounds were analyzed from 26 samples by using a gas chromatography-mass spectrometer. Water soluble organic carbon(WSOC) was also analyzed by using a total organic carbon(TOC) analyzer. Among 6 classes with 68 target compounds detected, the classes of n-alkanoic and alkenoic acids ($326.67{\pm}75.40ngm^{-3}$) and dicarboxylic acids ($323.74{\pm}361.89ngm^{-3}$) were found to be major compound classes in the atmosphere of Anmyon Island. Compared to the previous results reported for 2005 spring samples at Gosan site, the concentrations of organic compounds at Anmyon Island were 3-10 times higher than Gosan site due to the difference of location and sampling period. The concentrations of organic compounds were varied with the atmospheric conditions. Significant increase of the concentrations of dicarboxylic and carboxylic acids in the smog episode indicated that secondary oxidation of organic compounds was major factor to increase OA concentration during smog episode in the Anmyon Island. It was found that the compositions of the OA measured at Anmyon Island were dependent on the air parcel trajectories.

• 환경영향평가
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• 제31권1호
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• pp.1-10
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• 2022

본 연구는 비점오염원 저감시설인 차집시설을 대상으로 다양한 강우조건에 따라 초기우수 유출수의 수질특성을 파악하고, 용존성 오염물질의 기원을 파악하기 위하여 수행되었다. 본 연구는 도시지역 내 위치한 G-배수구역의 10개 차집시설 중 비강우시에도 불명수가 유입되는 것으로 조사된 차집시설 #1, #5, #8, #9 및 #10 등 5개 지점에서 수질분석을 통하여 차집시설에서 비점오염물질의 유출특성을 파악하였다. 연구결과로써 강우량에 따라 차집시설에서 우수유출수의 수질특성에 영향을 받는 것으로 판단되었다. 비강우시 EC, BOD, TOC, TN의 평균농도는 강우시에 비하여 높은 것으로 조사되었으며, DO의 평균농도는 강우시에 비하여 낮은 것으로 조사되었다. 또한, 차집시설에서 유출수의 용존성 유기물은 주로 내부에서 생성된 유기물로 구성된 것으로 판단되었다. 우수유출수는 주변 환경에서 유입되는 오염물질의 영향을 많이 받으며, 강우로 인하여 차집시설의 외부로부터 유입되는 난분해성 휴믹계 물질이 많아진 것으로 판단된다.

• 한국대기환경학회지
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• 제31권5호
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• pp.482-492
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• 2015

Ground-based measurements were conducted from January 6 to 12 of 2015 for understanding characteristics of nitrogen containing carbonaceous aerosols as 16 amino acids at the Mokpo National University, Korea. The detailed amino acid components such as Cystine ($(SCH_2CH(NH_2)CO_2H)_2$) and Methionine ($C_5H_{11}NO_2S$) and their sources were analyzed by High-Performance Liquid Chromatography with Fluorescence Detection (HPLC-FLD) for behavior of secondary products in particulate matter. In addition, organic carbon (OC) and elemental carbon (EC) based on the carbonaceous thermal distribution (CTD), which provides detailed carbon signature characteristics relative to analytical temperature, and water soluble organic carbon (WSOC) by total organic carbon (TOC) analyzer were used to understand the carbon compound behaviors. The backward trajectories were discussed for originations of carbonaceous aerosols as well. Different airmasses were classified with the amino acids and OC thermal signatures. The results can provide to understand the aging process influenced by the long-range transport from East Sea area.

• 상하수도학회지
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• 제13권1호
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• pp.61-71
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• 1999

For a high-rate fermentation and recovery of organic acid, we have developed a new organic acid fermentation reactor with membrane filter, which is the most important part in the new advanced wastewater treatment system. The recovered organic acid is to be reused as an organic carbon source at denitrification process. Some experiments were conducted to compare the performance of acid fermentation at different SRTs, such as 5, 10, and 20 days. The total organic acid concentration produced during the runs was in the range of 2,100-2,900 (mgC/L). The conversion efficiency from substrate to organic acid reached to from 43% to 59%. The recovery rate of organic acid from substrate based on TOC was from 26% to 53%. Regardless of operational conditions, it has been able to maintain the membrane flux constantly, in the range of 0.4-0.46 ($m^3/m^2/day$). The transmembrane pressure drop was 0.2-0.3 (kg/cm) for 100 day's operation. The result of simulation is as follows. Organic removal efficiency of the new advanced treatment system is 95%. 73% of Nitrogen is removed. The removal efficiency of Phosphorus is 93%. By coqulation, soluble phosphorus is able to remove from the water treatment lines, which is impossible at conventional activated sludge system. The unit construction cost is 65000 (yen/m3) and it was 1.4 times than that of the standard activated sludge system. The unit operation cast is 7.7 ($yen/m^3/day$) and it was 1.3 times than that of the standard activated sludge system.

• 대한환경공학회지
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• 제33권7호
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• pp.523-529
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• 2011

본 연구는 MBT시스템과 연계된 호기성안정화장치에서 입경 크기가 안정화에 미치는 영향을 검토하기 위하여 실시되었다. 반응기내 생분해성 폐기물(음식물류 폐기물 60%, 종이류 폐기물 25%, 목재류 폐기물 2% 및 퇴비 5%)을 동일한 조성으로 충전하고, 각각의 입경을 5 mm, 10 mm, 20 mm, 50 mm, 100 mm 및 미선별 등으로 조절하여 충전한 후에 안정화 정도를 비교분석하였다. 실험결과 온도변화에서는 50 mm 이하의 입경에서 최고 온도가 $65^{\circ}C$ 이상을 보였으며, 100 mm와 미선별 반응기에서는 최고온도가 약 $50^{\circ}C$를 보였다. $CO_2$ 가스의 발생량은 입경의 크기에 따라 발생량이 비례하는 현상이 관찰되지 않고, 오히려 100 mm 이상에서 높은 발생량을 보였다. 반응과정중 습윤 및 건윤기준의 무게변화는 입경 크기가 가장 작은 5 mm에서 각각 30% 및 46%의 감소율을 보였으며, 입경이 클수록 감소율이 낮아지는 경향을 보였다. 물용출 $COD_{Cr}$ 및 TOC는 입경 크기가 50 mm 이하인 반응기에서는 반응초기 대비 감소율이 약 80%로 나타난 반면 입경이 100 mm 및 미선별 반응기에서는 약 60%의 감소율을 나타내었다. 이러한 결과로부터 생분해성 폐기물의 입경이 작을수록 유기물의 분해율이 높아져 생분해성 물질의 분해 안정화가 촉진되는 것으로 나타났으며, 가능한 50 mm 이하로 입경을 조절하여 반응시키는 것이 필요한 것으로 나타났다.