• 대한환경공학회지
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• 제37권2호
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• pp.73-80
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• 2015

본 연구에서는 잔류의약물질로써 환경에서 노출 빈도가 높은 항생물질인 Tetracycline (TTC)을 대상으로 수용액 상에서의 망간산화물(birnessite)을 이용한 산화-변환 반응을 통한 제거와 용존성 자연유기물인 휴믹산(HA) 존재에 따른 영향을 조사하였다. TTC의 산화-변환 제거 특성 실험은 다양한 반응조건(반응시간, 망간산화물 주입량 및 pH 등)에서 회분식으로 조사하였으며, HA의 영향은 pH (3~9)와 HA농도 변화에 따라 조사하였다. 실험결과는 유사-일차 반응속도식을 적용하여 해석하였으며, 본 실험조건(TTC=0.25 mM, ${\delta}-MnO_2=1.0g/L$)에서의 TTC의 산화-변환 제거 반응속도상수(k, $hr^{-1}$)는 pH가 감소함에 따라 0.98 (pH 9)에서 2.97 (pH 3)로 일정하게 증가하였고, 망간산화물 주입량(1~2 g/L)이 2배 증가할 때 반응속도 상수는 약 1.3배 정도 증가하였다. HA (5 mg-C/L) 존재 시 망간산화물에 의한 TTC 변환제거는 $pH{\geq}6$에서 반응효율 상승을 나타냈으며, HA의 주입농도(1~10 mg-C/L, at pH 6)의 증가에 따라 일정하게 증가함을 확인하였다. 이상에서 얻은 연구결과는 기존 문헌에 제시된 TTC 반응기작과 비교 해석하였고, 망간산화물을 매개로 한 TTC의 산환-변환 제거 반응특성과 HA의 존재가 미치는 영향에 대하여 고찰하였다.

• 한국환경과학회지
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• 제22권11호
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• pp.1509-1517
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• 2013

So far, most studies associated with soil carbon sequestration have been focused on long term aspect. However, information regarding soil carbon sequestration in short term aspect is limited. This study was conducted to determine changes of soil organic carbon content and stability of carbon in response to compost application rate and tillage management during rice growing season(150 days) in short term aspect. Under pot experiment condition, compost was mixed with an arable soil at rates corresponding to 0, 6, 12, and 24 Mg/ha. To determine effect of tillage on soil carbon sequestration, till and no-till treatments were set up in soils amended with application rate of 12 Mg/ha. Compost application and tillage management did not significantly affect soil organic carbon(SOC) content in soil at harvest time. Bulk density of soil was not changed significantly with compost application and tillage management. These might result from short duration of experiment. While hot water extractable organic carbon(HWEOC) content decreased with compost application, humic substances(HS) increased. Below ground biomass of rice increased with application of compost and till operation. From the above results, continuos application of compost and reduce tillage might improve increase in soil organic carbon content and stability of carbon in long term aspect.

• 상하수도학회지
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• 제18권5호
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• pp.588-597
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• 2004

In this research, we investigated the variation of transmembrane pressure and permeate water quality with pre coagulation and sedimentation with iron based coagulant and chlorination of feed water for PVDF (polyvinylidene fluoride) based MF membrane filtration. NaCIO was fed to the membrane module with dosage of 0.5mg/L and maintained during filtration. To observe the effect of raw water, three types of raw and processed waters, including river surface water, coagulated water and coagulated-settled water, were applied. In case of river surface water, the transmembrane pressure increased drastically in 500 hours of operation. On the contrary, no significant increase in transmembrane pressure was observed for 1,200 hours of operation for coagulated water and coagulated-settled waters. The turbidity of permeate was lower than a detection limit of equipment for all raw waters. The removal efficiency of humic substances of coagulated water and coagulated-settled water was approximate ten times of that of surface river water. And, the removal efficiency of TOC and DOC was approximate two times of that of surface river water. From the results of plant operation, stable operation was maintained at $0.9m^3/m^2{\cdot}day$ filtration flux through the combination of pre-coagulation and pre-chlorination. However, the water quality of permeate was the best when pre-coagulation-sedimentation process was combined with pre-chlorination.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.45-55
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• 2003

연구의 목적은 광산활동에 의해 발생된 폐재에 의해 오염된 토양에 포함된 중금속의 존재형태와 용출특성에 대하여 비교 분석하는데 있다. 실험에 이용된 중금속 존재형태 분류는 다섯가지로 adsorbed, carbonate, reducible, organic과 residual 형태로 나누었다. 토양내 유기물의 함량 정도는 상동광산에서 발생된 광미가 석탄폐재보다 낮은 것으로 나타났다. 오염된 토양의 중금속 용출 실험에 의하면 석탄폐석과 광미내의 카드뮴의 경우 낮은 용출량을 보였으며, 대부분이 reduciblel fraction에서 용출된 것으로 관찰되었다 상동광산에서 발생된 광미에 포함된 니켈은 혐기성 상황이 되면 총량의 약 46.4％가 용출될 것으로 사료되며, 구리의 경우 약 39.4%가 용출될 것으로 판단된다. pH 3.0과 pH 5.6의 용출조건하에서 석탄 폐석과 광미의 용출랑의 점진적인 증가는 30분안에 이루어졌으며, 광미의 경우 니켈은 pH 3.0과 pH 5.6에서 용출 3시간까지 계속 증가되는 상태를 보였다.

• 한국대기환경학회지
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• 제34권3호
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• pp.418-429
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• 2018

Measurements of 24-hr size-segregated ambient particles were made at an urban site of Gwangju under high pressure conditions occurred in the Korean Peninsula late in March 2018. The aim of this study was to understand the effect of air stagnation on mass size distributions and formation pathways of water-soluble organic and inorganic components. During the study period, the $NO_3{^-}$, $SO_4{^{2-}}$, $NH_4{^+}$, water-soluble organic carbon (WSOC), and humic-like substances(HULIS) exhibited mostly bi-modal size distributions peaking at 1.0 and $6.2{\mu}m$, with predominant droplet modes. In particular, outstanding droplet mode size distributions were observed on March 25 when a severe haze occurred due to stable air conditions and long range transport of aerosol particles from northeastern regions of China. Air stagnation conditions and high relative humidity during the study period resulted in accumulation of primary aerosol particles from local emission sources and enhanced formation of secondary ionic and organic aerosols through aqueous-phase oxidations of $SO_2$, $NO_2$, $NH_3$, and volatile organic compounds, leading to their dominant droplet mode size distributions at particle size of $1.0{\mu}m$. From the size distribution of $K^+$ in accumulation mode, it can be inferred that in addition to the secondary organic aerosol formations, accumulation mode WSOC and HULIS could be partly attributed to biomass burning emissions.

• 환경위생공학
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• 제22권3호
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• pp.13-26
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• 2007

Changes in the characteristics of dissolved organic matter was studied at selected stations in the Nakdong river basin using physical and chemical methods. Characteristics of dissolved organic matters were analysed and assessed. Production of disinfection byproducts were also investigated. 1. Result of relatedness study among each items of analyses showed that relatedness on BOD values were highest with cattle excrement treatment facilities where there is no synthetic organic materials and relatedness on $COD_{Mn}$ were highest at the mainstream Nakdong river. In case of $COD_{Cr}$ (which has more oxidative power than $COD_{Mn}$), the values were higher in the sidestreams indicating the higher content of recalcitrant compounds. The relatedness values for the $UV_{254}$ also showed higher values in the sidestreams and treatment facilities than mainstream indicating the presence of organic aromatic compounds. 2. Ratio of DOC on total organic carbon were higher in the mainstream which is attributable to the influent particulate organic materials produced by agricultural activities. The values were 10-15% higher in the mainstream compared with sidestreams. 3. Result of biodegradability test indicate that concentrations of recalcitrant DOC were higher in the sidestreams than in the mainstream. The values of recalcitrant DOC were higher with the forest stream indicating the effect of soil oriented humic substances. 4. Result of THM production test carried out at 10 stations in the Nakdong river show that $CHCl_3$ was detected with the highest value and the value was highest at Waekwan station.

• 한국물환경학회지
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• 제25권5호
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• pp.697-703
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• 2009

In this study, changes in the composition of dissolved organic carbon (DOC) were investigated using water samples collected at a downstream site of the Namhan River near the Lake Paldang ($N37^{\circ}24^{\prime}05.33^{{\prime}{\prime}}E127^{\circ}32^{\prime}25.01^{{\prime}{\prime}}$) during a heavy rain event from July 23 to July 28, 2008. The DOC concentrations varied from 1.68 to 3.18 mg/L with the maxium value at a peak of the river water level. Each DOC sample was fractionated into three compositions including hydrophilic (Hi), hydrophobic acid (HoA) and hydrophobic neutral (HoN) fractions. The results showed that HoA was most abundant fractions, constituting 47.2~56.5% of DOC. Refractory dissolved organic carbon (R-DOC) contents were also determined by measuring the DOC concentration after 28-day dark incubation of the samples. R-DOC content was in the range from 83 to 99% of DOC and it was significantly correlated with HoA contents (r = 0.91, p<0.005), while it did not exhibit such a good correlation with the fractions of Hi and HoN (p>0.02). Our results suggest that the HoA, which is associated with humic substances, may be a major composition of refractory organic matters in rivers during storm events.

• 상하수도학회지
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• 제31권2호
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• pp.161-168
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• 2017

Microfiltration (MF) and Ultrafiltration (UF) membrane processes capable of producing highly purified water have been extensively applied as a pretreatment process in the wastewater reuse field with the improvement of membrane properties and resistance, development of operating protocols, and improvement of technologies of backwashing and physicochemical cleaning, and improvement of scale and antifoulants. However, despite of the development of membrane production and process technologies, fouling still remains unresolved. This study confirmed that foulants such as polysaccharides, proteins and humic substances existed in final treated effluent (secondary effluent) by fluorescence excitation emission matrix (FEEM) and fourier transform infrared spectroscopy (FTIR) analysis. In addition, when constructing ozone oxidation and coagulation processes as a hybrid process, the removal efficiency was 5.8%, 6.9%, 5.9%, and 28.2% higher than that of the single process using coagulation in turbidity, color, dissolved organic carbon (DOC), and UV254, respectively. The reversible and irreversible resistances in applying the hybrid process consisting of ozone oxidation and coagulation processes were lower than those in applying ozone oxidation and coagulation processes separately in UF membrane process. Therefore, it is considered possible to apply ozonation/coagulation as a pretreatment process for stable wastewater reuse by and then contributing to the reduction of fouling when calculating the optimal conditions for ozone oxidation and coagulation and then to applying them to membrane processes.

• Membrane and Water Treatment
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• 제9권3호
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• pp.163-172
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• 2018

This study investigated the effect of organic matter on the precipitation of struvite and calcium phosphate for phosphorus recovery from synthetic dairy wastewater. Batch precipitation experiments were performed to precipitate phosphorus from solutions containing $PO_4{^{3-}}$ and $NH_4{^+}$ by the addition of $Mg^{2+}$ and $Ca^{2+}$, separately, at varying pH, Mg/P and Ca/P molar ratios, and organic matter concentrations. Soluble total organic solids exhibited more inhibition to precipitation due to potential interaction with other dissolved ionic species involved in phosphorus precipitation. Xylan with low total acidity only exhibited significant inhibition at very high concentrations in synthetic wastewater (at up to 100 g/L). No significant inhibition was observed for Mg and Ca precipitation at relatively lower concentrations (at up to 1.2 g/L). MINTEQ simulations show that dissolved organic matter (DOM) as humic substances (HS) can cause significant inhibition even at relatively low concentrations of 0.165 g/L fulvic acid. However, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis suggested that xylan altered the crystal structure of both precipitates and had caused the formation of smaller sized struvite crystals with slightly rougher surfaces This could be due to xylan molecules adhering on the surface of the crystal potentially blocking active sites and limit further crystal growth. Smaller particle sizes will have negative practical impact because of poorer settleability.

• 공업화학
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• 제10권6호
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• pp.838-842
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• 1999

하수종말처리장에서 배출되는 유출수를 공업용수로 재이용하고자 방사선 조사방법을 이용하였다. 시료는 유출수를 모래여과한 후 사용하였다. 방사선원으로는 Co-60가 사용되었으며 조사량은 1 kGy부터 15 kGy로 변화시켰다. 하수처리수를 공업용수로 재활용하고자 할 때 가장 제거하기 어려운 색도의 주 원인물질은 휴민물질이었다. 이들은 방사선 조사선량 5 kGy에서 잘 제거되었다. 박테리아 역시 낮은 조사선량에서 살균이 이루어졌다. 그렇지만 방사선처리 후에도 여전히 미량의 유기물은 제거되지 않음을 알 수 있었다. 따라서 좀더 높은 질의 공업용수를 요구하는 곳에 이들을 재활용하고자 할 경우에는 추가적인 처리공정이 필요할 것이다.