• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.635-644
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• 1994

A mathematical model was developed to predict the concentrations of various nutrients in supernatants during aerobic digestion which is suitable to be employed in small wastewater treatment plants with such advantages as low capital cost and stable process. Significant reactions were determined with observing the behavior of nitrgen and phosphorus, and the model equations were built up in the form of simultaneous differential equations considering Mass Balance. Laboratory batch experiments were carried out at $20^{\circ}C$ and pH $7.5{\pm}0.5$ on the aerobic digestion of waste activated sludge at different solid levels. Nonlinear regression analysis was performed to estimate various reaction rate constants. The developed model can predict the behavior of Biomass N, dissolved organic N, $NH_4{^-}$-N, $NO_x{^-}$-N, and Biomass P, dissolved organic P, $PO_4{^-}$-P in aerobic digestion process. In this study, the results of simulation showed that dissolved nutrients had more effects on supernatants than nutrients in biomass, and phosphorus was more effective on supernatants than nitrogen.

• Journal of Wetlands Research
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• v.19 no.2
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• pp.216-222
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• 2017

Recently, opinions on the need for revision regarding the nitrogen effluent standard of nitrogen from sewage treatment plant(STP) are consistently suggested. However, it is axiomatic that if nitrogen effluent standard is strengthened without a clear basis, it will cause confusion in domestic STP. In this research, nitrogen fraction was analyzed based on a long-term incubation method, according to STP capacity, and the linked treatment of industrial wastewater. As a result, NBDDON, which is difficult to treat in STP, ranged from 1.0 to 1.9 mg/L. larger DON and NBDDON/DON was detected in small STP (under 10,000 m3 /d) as opposed to the large STP. NBDDON/DON in industrial STP was about 0.7 and it was higher than municipal STP. This research result will be used in the important raw data for revision of nitrogen effluent standard of nitrogen from STP.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.4
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• pp.519-534
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• 2019

When the fresh water from the artificial lakes (Ganwolho and Bunamho) were discharged to Cheonsu Bay in summer to prevent the flood over the reclaimed farmland near the lakes, the impact on water qualities (nutrients, organic matters, trace metals) within the bay was investigated through four surveys (June, July, August and October, 2011). Dissolved inorganic nitrogen (DIN) increased about as much as 3-4 times over the whole water column when the freshwater was discharged. And the main species composition of DIN changed from ammonia to nitrate. Dissolved inorganic phosphorus (DIP) decreased as much as 2 times in surface waters, but increased as much as 1.5 times in deep waters, and also silicate concentrations increased as much as 3-4 times in deep waters of the inner bay. The N/P ratios in Chunsu bay seawaters were much higher (2 to 7 times) than the Redfield ratio when the freshwaters were discharged, which indicated the phosphorus limiting in the phytoplankton growth. Dissolved organic carbon (DOC) and nitrogen (DON) increased as much as about 2 times. In addition, particulate organic matters (POC, PON, POP, Bio-Si) increased as much as above 2 times in the surface waters of the inner bay. Trace metals (Fe, Mn, Co, Ni, Cu) increased in the surface waters of the inner bay, but dissolved Cd concentrations decreased as much as 2 times. Therefore, when the contaminated fresh waters from the artificial lakes were discharged into the bay, nutrients, organic matters and trace metals generally increased compared to normal period. Since the phytoplankton bloom occurred in the surface waters of the inner bay, dissolved oxygens at the surface waters were oversaturated and hence hypoxic in the deep waters. Highly enriched nutrients concentrations were found in deep waters of the inner bay, which was accompanied with the hypoxic condition. Finally, the water quality in the inner bay of the Chunsu bay was deteriorated from less than grade 3 in normal periods to grade 5 when the freshwaters from the artificial lakes were discharged in summer.

• KSBB Journal
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• v.18 no.3
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• pp.211-216
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• 2003

The removal yield of dissolved organic matter in drinking water by biological activated carbon (BAC) process was investigated. The tested processes wer raw water-AC process (BAC1), raw water-ozonation-BAC process (BAC2), and raw water-ozonation-coagulation/sedimentation-BAC process (BAC3). The amounts of organic matter was measured as dissolved organic carbon (DOC), ulta-violet radiation at 254 nm wavelength ($UV_{254}$), total nitrogen (T-N), ammonia nitrogen (NH_3$-N), and total phosphate (T-P). As a results, 30.7% DOC was removed by BAC2 process, which showed higher removal efficiency than BAC1 or BAC3 processes. The removal yield of $UV_{254}$ in BAC1, BAC2, and BAC3 processes were observed as 45.3%, 44.6%, 58.4%, respectively. And the removal yield of ammonia nitrogen were 66%, 81%, 29% in each BAC processes. The optimal empty bed contact time (EBCT) of BAC processes was estimated as 10 minute. This study has shown that BAC process combined with ozone treatment was efficient for removing dissolved organic matter in water.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1093-1097
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• 2006

하천수계는 여러 인자들의 상호작용을 통하여 변화하게 되며, 하천 자정능력에 관한 연구는 이를 중심으로 진행되어 왔다. 여러 환경 요인 중 하상재료는 하천의 조도와 수생태계의 특성을 변화시키게 되며, 유입수의 성상에 따라 수저퇴적물이 쌓이거나, 생물막이 형성되는 매개체 역할을 하게 된다. 특히, 하천의 폭이 좁고 수심이 얕은 개울에서는 하상 퇴적물이 수질에 기여하는 영향이 큰 것으로 알려져 있다. 국내하천의 경우 하상재료가 주로 모래와 자갈이 주를 이루고 있으며, 수심이 낮아 빛의 투과성이 양호하여 부착조류의 증식 및 하상재료(모래 및 자갈 등)를 기질로 한 생물막 형성 등 하상재료는 하천환경의 변화 및 수질변화가 일어나는데 상당한 기여를 하는 것으로 보고되고 있다. 본 연구에서는 하천의 하상재료가 설치된 수로를 이용하여 이화학적요소를 조사, 분석함으로써 하상재료를 통한 수질변화 특성을 비교.검토 하였다. 그 결과 하상재료의 입경이 클수록 DO 변화가 더 큰 폭으로 증가 하였으며, 수위와 유속의 경우 수위가 낮으면서 유속이 적정수준일 경우 DO 증가가 나타나는 것으로 관측되었다. 하천수가 수로에 의해 순환되면서 유기물 저감속도의 측정결과 초기 흡착, 침전 등의 물리적 작용이 부착조류 증식 등의 생물학적 작용보다 우선되면서 입자성 유기탄소(POC)의 제거속도가 용존성 유기탄소(DOC) 의 경우보다 더 빠르고 우선되는 것으로 조사되었다. 영양염류의 경우 부착성조류에 의한 질소 제거능은 실제 질산화작용은 활발히 이루어졌으나 탈질작용에 의한 총질소의 제거는 미비한 것으로 나타났으며, 총인은 입자성유기탄소가 제거되는 것과 유사한 경향을 나타내 제거 기작이 대부분 흡착, 침전에 의한 물리적 자정 작용에 기인한 것으로 조사되었다. 또한 하상재료 입경 변화에 따른 수질변화 특성은 기질(하상재료)의 입경이 작을수록 오염물질의 분해능이 큰 것으로 나타났다. 이와 같이 여러 하천환경 요인 중 하상재료에 의한 하천환경의 다양한 변화는 수질변화 및 자정능력에 큰 영향을 미치게 된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.987-992
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• 2007

충청북도 내의 농업용 저수지중 26개소를 선정하여 관개초기, 홍수기 및 비관개기의 연 3회에 걸쳐 저수율을 파악하고 채수를 실시하였다. 또한, 현장(수온, pH, DO, EC)과 실내 수질분석(Cd, As, Cn, Hg, 유기인, Pb, $Cr^{+6}$ PCB, ABS, COD, SS, TP, TN)을 실시하여 저수지의 오염도를 평가하였다. 저수율 측정결과, 홍수기(97%)가 관개초기(72%)나 비관개기(66%)보다 높게 나타났다. pH 값의 측정결과, 수질기준$(6.0{\sim}8.5)$을 만족하고 있는 저수지의 비율은 35%(9개소)의 낮은 값을 보였다. EC와 DO 및 SS농도의 측정결과, 거의 모든 저수지에서 수질기준을 만족하고 있었으며, COD, TN, TP농도 측정결과, 수질기준 만족도는 관개초기 100%, 홍수기 81%, 비관개기 65%로 나타나, 저수량이 많은 관개초기보다 저수량이 적은 비관개기에 질소와 인의 관리가 필요한 것으로 판단된다. 또한, 사람의 건강항목(CN, Hg, 유기인, PCB, Cd, 비소As, Pb, $Cr^{6+}$, ABS)은 모든 저수지에서 관개 초기, 홍수기 및 비관개기에 모두 수질기준을 만족하였다. 점오염원을 관리하기 위해서는 저수지 상류유역에 있는 마을하수도를 정비하고, 축산분뇨처리시설 등을 설치하여 저수지로의 유입부하량을 저감할 필요가 있다. 또한, 비점원오염을 관리하기 위한 대책으로서, 질소농도를 저감시키기 위해서는 용존성 성분을 제공하는 비료의 시용량을 줄여야하며, TP농도를 저감시키기 위해서는 강우시 입자성 인의 유출을 제어할 필요가 있으며, 이를 위해서는 비가 많이 오는 여름철에 나지(裸地)나 밭에 식생이나 멀칭(mulching) 등으로 토양침식을 방지할 필요가 있다.가용한 장 단기간의 관측자료와 물수지 분석 연산식의 추정치를 바탕으로 관측자료에 의한 물수지 분석을 수행하였다. 분석 결과로 산지 소하천 유역인 설마천 시험유역의 각 수문요소의 물이동간의 정량적인 값을 알 수가 있었으며, 앞으로 추가적이고 지속적인 수문모니터링이 운영되고 물순환 해석 모형에 의한 검증이 수행된다면 정량적인 물순환 관계를 규명할 수 있을 뿐만 아니라 이와 관련된 수문요소기술을 확보할 수 있을 것이다.절한 타협과 조정을 필요로 한다. 그러나 절제의 한계를 넘어선다고 생각되거나, 조정의 노력이 불가능하거나, 실패했을 때 폭력적인 행동으로 나타나게 된다. 리차즈(I.A Richards)는 분노와 공포는 일단 겉잡을 수 없는 경향이 있다고 하면서 오늘날 폭력에 대한 요구가 일상의 정서 생활에 있어, 억압을 통한, 빈곤함을 반영하고 있지 않은지 생각해봐야 할 것이라고 충고한다. 조성 가이드라인(안)을 제시하였다.EX>$\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기 중엽 경제적 태평과 함께 백자의 수요 생산이 증가하자 군신의 변별(辨別)과 사치를 이유로 강력하게 규제하여 백자의 확대와 발전에 걸림돌이 되었다. 둘째, 동기(銅器)의 대체품으로 자기를 만들어 충당해야할 강제성 당위성 상실로 인한 자기수요 감소를 초래하였을 것으로 사료된다. 셋째, 경기도 광주에서 백자관요가 운영되었으므로 지방인 상주지역에도 더 이

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.2
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• pp.151-159
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• 1997

Benthic respiration and chemical fluxes were measured at the sediment-water interface underlying the marine fish cages floating on the open coastal waters off Tong-Young, the South Coast of Korea. The effects of cage farming on coastal benthic environment and on mass balance of organic carbon in the benthic boundary layer under the marine fish cages are addressed. In a growing season of caged fishes of June, 1995, benthic chambers and sediment traps were deployed on the sediment-water interfaces of the two sites chosen for this study: 1) Cage Site, directly underlying the fish cages of the farm at 18 m water depth, and 2) Control Site, about 100 m away from the farm at 32 m water depth. Benthic respiration rates and chemical fluxes were calculated from the evolution of dissolved oxygen and chemicals in the chamber water, and mass balance of organic carbon in the benthic boundary layer was constructed based on the vertical flux of particulate organic matter (POM) and chemical fluxes out of the sediment. High organic dumping (6400 mg C $m^{-2}d^{-1}$) and high benthic respiration (230 mmol $O_2\;m^{-2}d^{-1}$) were observed at the Cage Site. Equivalent to 40% of vertical flux of organic carbon into the Cage Site seemed to be decomposed concurrently and released back to overlying waters (2400 mg C $m^{-2}d^{-1}$). Consequently, up to 4000 mg C $m^{-2}d^{-1}$ of organic carbon could be buried into the farm sediment (equivalent to 60% of organic carbon flux into the Cage Site). At the Control Site, relatively less input of organic carbon (4000 mg C $m^{-2}d^{-1}$) and low benthic respiration rate (75 mmol $O_2\;m^{-2}d^{-1}$) were observed despite short distance away from the cages. The influence of cage farming on benthic chemical fluxes might be restricted and concentrated in the sea bottom just below the fish cages in spite of massive organic dumping and high current regime around the fish cage farm.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.2
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• pp.109-124
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• 2014

In order to understand the carbon cycle in the Amundsen Sea of the Southern Ocean, the export fluxes of particulate organic carbon from the euphotic zone to deep water estimated using ${\psi}$/${\psi}$ disequilibrium method. Seawaters in 14 water columns were collected during February and March 2012, and analyzed for total and dissolved ${\psi}$, and particulate organic carbon. Total ${\psi}$ activities in the water column showed deficiency and excess relative to those of ${\psi}$ depending on the water depth. Deficiency of total ${\psi}$ in the euphotic zone showed mirror images both with chlorophyll-a and fluorescence, and was consistent with the loss of nitrate, which indicated the effect of biological activity. In addition, deficiency of total ${\psi}$ from deep water was associated with the increase of total dissolvable Fe/Mn concentration. Excess total ${\psi}$ activity presented below the euphotic zone might be related to particulate ${\psi}$ concentrated in this water depth. Mean export flux of ${\psi}$ estimated using the steady state model was $867{\pm}246dpmm^{-2}day^{-1}$. Mean export flux of particulate organic carbon, which were estimated by the product of total ${\psi}$ flux and ratio of POC/${\psi}$ ($7.08{\pm}4.27{\mu}molCdpm^{-1}$) in the sinking particles, was $5.9{\pm}3.9mmolCm^{-2}day^{-1}$. These fluxes were similar levels to those in the Weddell Sea during February and March 2008. Export ratios (ThE) relative to the primary production in the euphotic zone were in the range of 3-54% (av. 28%).

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.382-390
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• 2010

In this research hydrogen sulfide, ammonia and toluene were designated as the representative source of malodor and VOC, respectively, frequently generated at the compost manufacturing factory and publicly owned facilities. The optimum operating condition to treat the waste air(2 L/min) containing malodor was constructed using photocatalytic reactor/biofilter process with humidifier composed of fluidized aerobic anf anoxic reactor. The ammonia(300 ppmv) of fed-waste air was removed by 22, 55 and 23% at the stage of photocatalytic reactor, humidifier and biofilter, respectively. The toluene(100 ppmv) of fed-waste air was removed by 20, 10 and 70% at the stage of photocatalytic reactor, humidifier and biofilter, respectively. Therefore the water-soluble ammonia and the water-insoluble toluene were treated mainly at the stage of humidifier and biofilter, respectively. In addition, hydrogen sulfide(10 ppmv) was almost treated at the stage of photocatalytic reactor and its negligible trace was absorbed in humidifier so that it was not detected before biofilter process. The nitrate concentration of the process water from anoxic reactor was found lower by 3 ppm than that from fluidized aerobic reactor. Besides, the dissolved ammonia-nitrogen concentration of the process water from humidifier remained at the high value of 1,500-2,000 ppm, which may be attributed to the existence of ammonium chloride and other source of ammonium nitrogen.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.80-89
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• 2017

Researches about NPS(Non-point Pollution Source) reduction have been widely carried out in recent years. A pilot channel-type constructed wetland (wet swale) was constructed in Rongyin area to treat stormwater generated from a green house agro-land of 22.7 ha. From 2006 to 2008, monitoring was conducted to evaluate its performance on the removal effect for organic pollutants as well as nutrients. Totally, sampling trips of 17 rainfall events were made and they covered most types of storm events in Korea. The channel-type constructed wetland have average removal efficiencies of 78.3~92.0%, 56.4~66.1%, 28.2~45.5% and 50.6~66.4% for SS, COD, TN and TP, respectively. According to four methods for estimating the removal efficiency, the average efficiencies of TSS, COD, TN and TP are 86.0%, 60.1%, 30.1% and 53.5%, respectively. From 2006 to 2008, annual efficiency improved due to infiltration potential increase. It was found that most of the pollutants removed in this channel type of wetland was particulate solids bound pollutants, which is assumed fact that it lacks of physico-chemical treatment conditions which are commonly observed in the retention type of constructed wetlands.