• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.261-261
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• 2022

최근 국내 녹조현상의 빈도가 잦아지고, 지속기간이 증가하였다. 이러한 녹조현상은 이상기후로 인한 일사량, 수온, 체류시간 증가로 인한 환경적인 영향이 있으며, 산업단지 및 농지 등에서 유출되는 질소나 인의 부영양화로 인한 인위적 영향이 있다. 조류종 중 특히 남조류가 생장하는 과정에서 발생하는 독성물질(간독소, 신경독소), 이취미 물질(Geosmin, 2-MIB 등)은 수질을 악화시키고 있어 생태계에 큰 영향을 미친다. 조류는 하천에서 넓은 분포로 발생하게 되는데 현재 조류 조사 방법은 현장에 발생한 조류를 직접 채취하여 연구실에서 현미경으로 직접 검경하기 때문에 많은 인력과 시간, 비용이 소비되고 있는 실정이다. 국내에서는 인력과 시간을 줄이기 위해 센서를 활용한 조류분석 및 원격탐사 기법을 이용한 조류 모니터링에 대한 연구가 많이 진행되고 있다. 하지만 하천에서는 녹조류와 남조류 모두 혼합되어 존재하며 센서를 이용하여 조류를 분석할 시 녹조류는 Chl-a, 남조류는 Phycocyanin을 대체하여 분석하고 있다. 하지만 모든 조류는 광합성을 하기 때문에 Chl-a를 모두 함유하고 있어 Chl-a만으로 남조류를 추정하는 데에는 한계가 있다. 따라서 본 연구에서는 조류 계측장비인 LISST-HAB를 통하여 조류시료의 농도를 측정하여 Chl-a, Phycocyanin 농도를 측정하여 조류종 분류에 대한 분석을 진행하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.87-87
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• 2022

최근 국내외 이상기후 변화로 인해 일사량 증가 및 하천, 호소의 체류시간이 늘어남에 따라 조류의 과대성장이 빈번히 발생하고 있다. 하천의 조류는 크게 녹조류, 남조류, 규조류로 분류되며, 남조류 중 일부 종은생장하는 과정에서 생성하는 냄새물질, 독성물질의 배출로 문제를 야기하고 있다. 국민의 안전을 도모하기 위해 국내에서는 조류경보제, 수질예보제를 시행하고 있으며, 이는 유해남조류세포와 Chl-a농도에 따라 발령이 된다. 이렇듯 유해남조류와 Chl-a 측정은 매우 중요하며, 현재 조류의 분석방법은 현장샘플을 하여 조류검경을 통해 산정하기 때문에 시간이 많이 소요되며, 조류발생시 즉각대응이 힘들며, 육안으로 유해남조류인지 구별하기가 어렵다. 최근 원격탐사를 통해 조류의 대체 인자인 Chl-a, Phycocyanin을 통해 조류농도를 분석하고 있으나, 광합성을하는 모든 조류에는 Chl-a가 함유되어 있어 남조류와 녹조류의 정확히 구별하는데 한계점이 있다. 본 연구에서는 조류배양액을 초분광센서를 통해 조류스펙트럼을 취득하고, 남조류와 녹조류의 최대 흡수 스펙트럼을 추출하여 스펙트럼의 순간기울기 변화를 통해 남조류와 녹조류의 종분류하였다.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.137-146
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• 2007

This study was conducted to determine fertilizer nutrient and pollutant production of Holstein dairy cattle by estimating manure characteristics. The moisture content of feces was 83.9% and 95.1% for urine. The pH of feces and urine were in the ranges of 7.0～7.4 and 7.5～7.8, respectively. The average BOD5, COD, SS, T-N, T-P concentrations of the dairy feces were 18,294, 52,765, 102,889, 2,575, and 457mg/ℓ, respectively. Dairy urine showed lower levels of BOD5(5,455mg/ℓ), COD(8,089mg/ℓ), SS(593mg/ℓ), T-N(3,401mg/l), and T-P(13mg/ℓ) than feces. The total daily produced pollutant amounts of a dairy cow were 924.1g(Milking cow), 538.8g(Dry cow), 284.4g(Heifer) of BOD5, 2,336.5g (Milking cow), 1,651.8g(Dry cow), 734.1g(Heifer) of COD and 4,210.1g(Milking cow), 2,417.1g(Dry cow), 1,629.1g(Heifer) of SS and 194.8g(Milking cow), 96.4g(Dry cow), 58.3g(Heifer) of T-N and 24.0g(Milking cow), 10.2g(Dry cow), 6.1g(Heifer) of T-P. The calculated amount of pollutants produced by a 450kg dairy cow for one year were 181.3kg of BOD5, 492.5kg of COD, 899.9kg of SS, 36.0kg of T-N and 4.1kg of T-P. The total yearly estimated pollutant production from all head(497,261) of dairy cattle in Korea is 90,149 tons of BOD5, 244,890 tons of COD, 447,491 tons of SS, 17,898 tons of T-N and 2,008 tons of T-P. The fertilizer nutrient concentrations of dairy feces was 0.26% N, 0.1% P2O5 and 0.14% K2O. Urine was found to contain 0.34% N, 0.003% of P2O5 and 0.31% K2O. The total daily fertilizer nutrients produced by dairy cattle were 197.4g (Milking cow), 97.4g(Dry cow), and 57.9g(Heifer) of Nitrogen, 54.2g(Milking cow), 22.2g(Dry cow), and 14.2g(Heifer) of P2O5 and 110.8g(Milking cow), 80.4g (Dry cow), and 39.5g(Heifer) of K2O. The total yearly estimated fertilizer nutrient produced by a 450kg dairy animal is 36.2kg of N, 8.8kg of P2O5, 24.6kg of K2O. The estimated yearly fertilizer nutrient production from all dairy cattle in Korea is 18,000 tons of N, 4,397 tons of P2O5, 12,206 tons of K2O. Dairy manure contains useful trace minerals for crops, such as CaO and MgO, which are contained in similar levels to commercial compost being sold in the domestic market. Concentrations of harmful trace minerals, such as As, Cd, Hg, Pb, Cr, Cu, Ni, Zn, met the Korea compost standard regulations, with some of these minerals being in undetected amounts.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.11-20
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• 2012

The aim of this study is to accumulate the data about the roof-harvested rainwater quality characteristics for the better rainwater management. According to the results of rainwater quality indicators (pH, COD, TSS, T-N, T-P, $NH_4$-N, $NO_3$-N, enteric bacteria, heterotrophs, Pb, Cd, Cu), the rainwater qualities of the first flush of roof-harvested was the most polluted about 2 or 3 times (more than 100 times in microbial contamination) compared to the qualities of directly collected rainwater. In the first 10 min flush, over the 60% amounts of contaminant were released from the roof during 30 minute rainwater monitoring. Through statistical factor analysis, relatively close items(variables) can be categorized. It is expected that the continuous monitoring of the roof-harvested rainwater will help to design the safe and economical rainwater storage system in Korea.

• Journal of Korea Water Resources Association
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• v.43 no.1
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• pp.95-104
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• 2010

The tap water supply in Korea mainly depends on the surface water. However, the advanced water purification process becomes a necessity due to the deterioration of surface water quality and the risk of accidental spill. High cost of water treatment and public concerns make the decision makers turn to riverbank filtration as an alternative to the surface water. Riverbank filtration has been employed for water supply in many developed countries for more than 150 years. In Korea, riverbank filtration has drawn attention since 1990s as a supply source having potential to stably meet the ever-increasing water demand. Some cities located in the Nakdong River Basin are currently supplying water through riverbank filtration. This work studies the site suitability analysis for riverbank filtration using game theory. Theory of games, which is a branch of applied mathematics used in social sciences (most notably economics), biology, engineering and computer science, was applied to candidate locations for the selection of riverbank filtration site. We proposed a policy game model as a new method adopting a probabilistic approach. The model developed turned out to be an effective tool for site selection.

• Journal of Korea Water Resources Association
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• v.42 no.8
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• pp.673-680
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• 2009

Alternatives to conventional water resources are being sought due to the scarcity and the poor quality of surface water. Riverbank filtration (RBF) is one of them and considered as a promising source of water supply in some cities. Changwon City has started RBF in 2001 and field data have been accumulated. This study is to develop a time-series model for groundwater level data collected from the pumping area of RBF. The site is Daesan-myeon, Changwon City, where groundwater level data have been measured for the last five years (Jan. 2003$\sim$Dec. 2007). Minute-based groundwater levels was averaged out to monthly data to see the long-term behavior. Time-series analysis was conducted according to the Box-Jenkins method. The resulted model turned out to be a seasonal ARIMA model, and its forecasting performance was satisfactory. We believe this study will provide a prototype for other riverbank filtration sites where the predictability of groundwater level is essential for the reliable supply of water.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.487-490
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• 2005

재생 가능한 자원인 동식물성 기름으로부터 만들어지는 수송용 연료 바이오디젤은 낮은 대기오염물질 배출과 $CO_2$ Neutral 특성으로 환경친화적인 연료로 인정올 받으며 전세계적으로 그 생산량이 급격히 증가하고 있다 한국에서는 년간 20만톤의 폐식용유가 배출되며 이중 약 10만톤이 회수 가능한 것으로 추산된다. 폐식용유의 무단 폐기로 인한 수질오염과 폐기물의 자원 재활용 및 에너지 생산 관점에서 폐식용유를 바이오디젤 원료로 사용하는 연구가 많이 진행되었다. 높은 함량의 유리지방산을 함유한 폐식용유를 효율적으로 전이에스테르화(methanolysis) 하기 위해서는 먼저 산 촉매를 이용한 유리지방산의 전환 제거가 필요하다 본 연구에서는 다양한 종류의 강산성 이온교환 수지를 폐식용유의 전처리(pre-esterification)용 고체 산 촉매로 회분식 반응기에서 테스트하였으며 그 결과 Amberlyst-15가 유리지방산의 에스테르화 반응에 가장 적합한 것으로 나타났다. 회분식 반응기에서 도출된 최적 전처리 반응조건을 적용한 200시간 이상의 연속 전처리 운전결과 폐식용유에 함유된 $5\%$의 유리지방산이 $90\%$이상 전환제거 되었다 전처리 반응 후의 폐식용유를 균질계 염기촉매(KOH) 존재하에 메탄올과 전이에스테르화 반응을 시킨 결과 바이오디젤로 불리는 지방산메틸에스테르(Fatty Acid Methyl Ester, FAME)의 생산 수율은 $85\%$로 얻어졌으며 국내 바이오디젤 표준 규격에 따른 연료특성 분석 결과 FAME의 농도 규격을 제외한 모든 항목이 국내 규격을 만족하였다 폐식용유 바이오디젤의 FAME 농도가 $94.3\%$로 국내 규격$96.5\%$에 미달하는 문제는 식물성 원료유로 제조한 고순도 바이오디젤과 혼합 사용하거나 감압 증류 공정을 통해 고농도의 폐식용유 바이오디젤을 제조하여 해결 가능하다. 대전시 신성동 소재의 음식점에서 수거한 폐식용유를 원료로 하여 생산한 바이오디젤의 차량 배출가스 실증 테스트 결과 경유 차량의 주 오염물질인 PM과 Soot 및 기타 오염물질의 배출량은 감소하였으나 NOx의 배출량은 약간 증가하는 것으로 나타났다

• Journal of Aquaculture
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• v.15 no.1
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• pp.1-6
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• 2002

Hydrological factors prevailing in the Namdae stream were as follows : temperature = -0.2~$26.8^{\circ}C$, salinity = 0.50~3.21$\textperthousand$, DO = 5.21~8.13 ppm, $PO_{4}-P$ = ND~1.37 ppm, $NO_{2-}$ = 0.10~0.81 ppm, COD = 1.53~2.82 ppm, $H_2 S$ = ND~0.0012 ppm and IL = 0.85~1.36 %. Sediment was typical, gravelly sand or sand with very good sorting value ranging from 0.53 to 1.77$\varphi$. Population density of the clam C. japonica ranged from 2 to 464/$m^2$. The clams were divided into four size classes, based on shell length of small (0~10 mm), medium (10~20 mm), large (20~30 mm) and largest (>30 mm), and were encountered at the frequency of 3.2, 50.4, 43.3 and 3.1 %, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.251-257
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• 2014

This research is focused on coagulation and sand filtration process as a pretreatment of RO seawater desalination. RO systems require sufficient and reliable pretreatment process to produce superior quality of RO feedwater that can mitigate RO membrane fouling. This experiment was conducted to investigate the effectiveness of coagulation and filtration process under various experimental conditions including different coagulant dose, flocculation mixing intensity and time, turbidity, and filtration rate. The experimental results showed that the optimum pretreatment conditions resulting in lower SDI value suitable for RO feedwater were coagulation pH 6.5, raw water turbidity greater than 4 NTU, and media bed depth greater than 550 mm. However, flocculation mixing intensity, coagulant dose, and filtration rate relatively affected little on the filtration efficiency.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.319-326
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• 2001

The biological and physicochemical factors and geosmin concentration were monitored in the Daechung Reservoir for 25 weeks from April to October in 1999. Geosmin was detected 5 times within a range of $1.16{\sim}5.28\;ng\;L^{-1}$, mostly in the late summer. The highest geosmin concentration was recorded on August 31, which also overlapped with the peaks of phycocyanin concentration, cyanobacterial density, and Anabaena spiroides density. A correlation analysis indicated that geosmin production was closely related with a high water temperature, pH, total dissolved phosphorus (TDP), and A. spiroides density. A water temperature of $27^{\circ}^C$, pH of 8.5, and TDP of $0.06\;mg\;L^{-1}$ were identified as the prerequisite environmental condition sand threshold values for geosmin production. Accordingly, under such conditions, an A. spiroides density above $10,000\;cells\;mL^{-1}$ indicates imminent geosmin occurrence.