• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.900-908
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• 2016

The effects of algal inoculation on chemical oxygen demand (COD) and total nitrogen (TN) removal, and indigenous bacterial dynamics were investigated in municipal wastewater. Experiments were conducted with municipal wastewater inoculated with either Chlorella vulgaris AG10032, Selenastrum gracile UTEX 325, or Scenedesmus quadricauda AG 10308. C. vulgaris and S. gracile as fast growing algae in municipal wastewater, performed high COD and TN removal in contrast to Sc. quadricauda. The indigenous bacterial dynamics revealed by 16S rRNA gene amplification showed different bacterial shifts in response to different algal inoculations. The dominant bacterial genera of either algal case were characterized as heterotrophic nitrifying bacteria. Our results suggest that selection of indigenous bacteria that symbiotically interact with algal species is important for better performance of wastewater treatment.

• 대한토목학회논문집
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• 제30권6B호
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• pp.551-560
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• 2010

본 연구에서는 현재 시행되고 있는 수질오염총량관리제 모니터링 시스템에 적용가능한 하천 오염부하량 추정기법을 제안하고 있다. 하도추적기능과 증발산량 계산 기능을 추가한 수정 TANK 모형을 이용하여 국립환경과학원에서 8일 간격으로 관측된 유량자료를 일 유량 자료로 확장하였다. 관측된 수질-유량 동시관측자료를 이용하여 7변수 대수선형모형의 매개변수를 최소분산 비편향 추정기법에 의해 추정하였다. 확장된 일 유량자료와 7변수 대수선형모형의 결과가 연계되어 관측지점별일 오염부하량이 계산되었다. 그 결과 SS, TN, TP 하천 오염부하량 추정에서 만족스러운 결과를 확인할 수 있었다. 적용의 일환으로 낙동강유역을 대표할 수 있는 SS, TN 및 TP 수질항목별 대표 단위면적당 부하량 유황곡선을 작성하였으며, 이를 통하여 낙동강 유역의 전체적인 하천오염부하량의 배출분포를 살펴보았다.

• Environmental Engineering Research
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• 제21권4호
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• pp.401-408
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• 2016

The aim of this study was to evaluate the biomass and lipid production of Chlorella vulgaris and its nutrient removal capability for treatment of brewery wastewater effluent. The results indicate that the maximum biochemical oxygen demand (BOD) (91.43%) and chemical oxygen demand (COD) (83.11%) were removed by C. vulgaris with aeration in the absence of light. A maximum of 0.917 g/L of dry biomass was obtained with aeration in the dark conditions, which also demonstrated the highest amount of unsaturated fatty acids at 83.22%. However, the removal of total nitrogen (TN) and total phosphorus (TP) with these aeration and light conditions was 9.7% and 11.86% greater than that of other conditions. The removal of BOD and COD and the production of biomass and lipids with aeration in the dark and the TN and TP removal with aeration and light were more effective than other conditions in the brewery wastewater effluent in the presence of C. vulgaris.

• 한국물환경학회지
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• 제24권4호
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• pp.480-487
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• 2008

Spatial and temporal analyses of water qualities were performed for 11 monitoring stations located in Mangyung watershed in order to analyze the trends of monthly water quality data of Biochemical Oxygen Demand (BOD), Total Nitrogen (TN) and Total Phosphorus (TP) measured from 1995 to 2004. The long-term trends were analyzed utilizing Seasonal Mann-Kendall test, LOWESS and three-dimensional graphs were constructed with respect to distance and time. The graph can visualize spatial and temporal trend of the long-term water quality in a large river system. The results of trend analysis indicated that water quality of BOD and TN showed the downward trend. This quantitive and quantitative analysis is the useful tool to analyze and display the long-term trend of water quality in a large river system.

• Journal of the Korean Data and Information Science Society
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• 제19권4호
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• pp.1019-1026
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• 2008

The goal of this paper is to analysis the trend of stream quality about the upstream, middle stream and high areas of Nakdong River measurement points from January 1998 to December 2006. and to suggest some policy alternatives in Nakdong river. It used the three different monthly time series data such as BOD (biochemical oxygen demand), TN (Total Nitrogen) and TP(Total Phosphorus), of the three of Nakdong River measurement points. BOD, TN and TP data are analyzed with the LOWESS(Locally Weighted Scatter plot Smoother) nonparametric method.

• 한국환경농학회지
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• 제21권4호
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• pp.269-273
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• 2002

근자연형 인공습지에 식재한 부들이 거의 죽지 않고 활착하였으며, 7월부터 새줄기가 일부 나오기 시작하였다. 부들의 활착과 성장은 양호한 편이었다. 개수부에는 부들의 새줄기가 나오지 않았다. 조사기간 인공습지의 평균 $NO_3-N$와 평근 TN 제거율은 각각 85.8 $mg/m^2/day$, 174.4 $mg/m^2/day$를 나타냈다. 북미에서 운영중인 인공습지의 평균$NO_3-N$ 제거율 125 mg $N/m^2/day$와 평균 TN 제거율 513 mg $N/m^2/day$ 보다는 다소 낮다. 이들 북미습지는 조성 후 수년이 지나 습지의 기질층이 $NO_3-N$ 및 TN 제거에 양호한 조건을 갖춘 습지들이다. 본 연구 인공습지의 조사기간이 조성 후 초기이고, 조사기간에 겨울철 일부 기간이 포함되어 있는 점을 고려하면 $NO_3-N$과 TN제거율이 양호한 편이라 사료된다. 본 연구습지의 부들이 2$\sim$3년 후 개수부 이외의 습지를 완전히 덮고, 부들의 잔재물이 습지바닥에 쌓여 탈질화에 필요한 탄소공급원의 역할을 하면 $NO_3-N$ 및 TN 제거율이 높아질 것으로 사료된다. 기존의 인공습지는 수질정화 측면을 강조하여 일정한 수심유지와 유입수의 단기이동 방지를 위해 습지바닥을 수평으로 균일하게 조성하여 왔다. 최근 들어 인공습지 설계에서 친환경적인 측면이 강조되는 추세이다. 본 근자연형 인공습지는 제방에 면한 습지바닥의 일부에 완만한 경사를 두고 습지외곽의 모습을 타원형으로 조성하여 자연습지의 모습과 가급적 유사한 모습으로 조성하였다. 초기 조사분석결과 질소정화가 정상적으로 이루어지고 있어, 습지일부에 완만한 경사를 도입하여 자연습지와 유사한 모습으로 수질정화 인공습지의 조성이 가능할 것으로 사료된다.

• ALGAE
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• 제20권4호
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• pp.333-343
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• 2005

Spatial and temporal variations of environmental factors and phytoplankton community were investigated in the three stations of Andong Reservoir in 1997 and 2003. The changes of physico-chemical water quality and phytoplanktonic biomass were higher in 2003 than that of 1997, due to rainfall difference. The concentration of total nitrogen (TN) and total phosphorus (TP) in the reservoir decreased, but total nitrogen fell relatively more between them. TN/TP ratio decreased from 109 to 90 showing no change at the downstream but a big decrease at the midand upstream. Predominant phylum of phytoplankton in Andong Reservoir were six genus that composed to Anabaena, Aphanizomenon and Microcystis of Cyanophyceae, Cosmarium and Scenedesmus of Chlorophyceae and Synedra of Bacillariophyceae, respectively. Among the observed phytoplankton, diatom Synedra occured as the maximum amount of 3,400 cells mL$^{-1}$ even at the above 30°C. Green algae Scenedesmus observed along with Microcystis. It seemed to be compete with Microcystis during the high water temperature period. Although trophic state of Andong Reservoir was decreased, the standing crops of phytoplankton were increased. Moreover bluegreen algae, Aphanizomenon and Microcystis in the region of upstream to midstream and diatom, Synedra in the region of midstream to downstream were increased until to reach the algal bloom, respectively. It seemed necessary to attention the changes of blue-green algae Aphanizomenon, that has an ability of nitrogen fixation.

• Journal of Ecology and Environment
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• 제39권1호
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• pp.31-42
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• 2016

The object of this study was to determine long-term temporal and spatial patterns of nutrients (nitrogen and phosphorus), suspended solids, and chlorophyll (Chl) in Chungju Reservoir, based on the dataset of 1992 - 2013, and then to develop the empirical models of nutrient-Chl for predicting the eutrophication of the reservoir. Concentrations of total nitrogen (TN) and total phosphorus (TP) were largely affected by an intensity of Asian monsoon and the longitudinal structure of riverine (Rz), transition (Tz), and lacustrine zone (Lz). This system was nitrogen-rich system and phosphorus contents in the water were relatively low, implying a P-limiting system. Regression analysis for empirical model, however, showed that Chl had a weak linear relation with TP or TN, and this was mainly associated with turbid, and nutrient-rich inflows in the system. The weak relation was associated with non-algal light attenuation coefficients (Kna), which is inversely related water residence time. Thus, values of Chl had negative functional relation (R² = 0.25, p < 0.001) with nonalgal light attenuation. Thus, the low chlorophyll at a given TP indicated a light-limiting for phytoplankton growth and total suspended solids (TSS) was highly correlated (R² = 0.94, p < 0.001) with non-algal light attenuation. The relations of Trophic State Index (TSI) indicated that phosphorus limitation was weak [TSI (Chl) - TSI (TP) < 0; TSI (SD) - TSI (Chl) > 0] and the effects of zooplankton grazing were also minor [TSI (Chl) - TSI (TP) > 0; TSI (SD) - TSI (Chl) > 0].

• 한국물환경학회지
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• 제21권5호
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• pp.470-476
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• 2005

The Korean Water Quality Index (K-WQI) was applied to the rivers located in the watershed of Daecheong Lake to assess the status of river water quality, and propose potential target constituents for better water quality management in the watershed. The estimated K-WQI value for each river was varied from 70 to 90, and Youngdongcheon showed the worst score while Mujunamdeachen showed the best score. The total nitrogen (TN) and total coliform bacteria were identified as the most significant constituents that degrade the K-WQI values in the rivers. The correlation coefficients (r) were determined between K-WQI and the delivered specific load ($kg/km^2/yr$) of BOD, TN, and TP to justify potential target constituents that have a great influence on the improvement of K-WQI values. The results showed that TN (r=-0.86) and TP (r=-0.85) have a strong negative relationships with K-WQI, but BOD have almost no effect. This implies that BOD, the surrogate parameter for organic pollutants, is no more a feasible water quality variable for the water quality management in the study site.

• 한국물환경학회지
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• 제20권1호
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• pp.63-71
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• 2004

The long-tenn trend analyses of water qualities were performed for 49 monitoring stations located in Nakdong River. Water quality parameters used in this study are the monthly data of BOD(Biological Oxygen Demand), TN(Total Nitrogen) and TP(Total Phosphorus) measured from 1990 to 1999. The long-tenn trends were analyzed by Seasonal Mann-Kendall Test and Locally WEighted Scatter plot Smoother(LOWESS). Nakdong river was divided into four subbasins, including upstream watershed, midstream watershed, western downstream watershed and eastern downstream watershed. The results of Seasonal Mann-Kendall Test indicated that there would be no trends of BOD in upstream watershed, western and eastern downstream watershed. Trends of BOD were downward in midstream watershed. For TN and TP, there were upward trends in all of watersheds. But LOWESS curves suggested that BOD, TN and TP concentrations generally increased between 1990 and 1996, then resumed decreasing.