• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.535-546
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• 2000

Juam lake is a major water resource for the industrial and agricultural activities as well as the resident life of Kwangju and Chonnam area. However, the water quality of the lake is getting worse due to a large quantity of pollutant inflowing to the lake. As a preliminary step in making the countermeasure to achieve the water quality goal of the lake. it is necessary to understand how the water quality of the lake will be in future. Several computer programs can be used to predict the water quality of lake. Each of these programs requires a number of input data such as hydrological and meteorological data. and the quantity of the pollutant inflowed. but some or most of the input data contain uncertainty. which eventually results in the uncertainty of prediction value (future level of water quality). Generally. the uncetainty stems from the lack of information available. the randomness of future situation. and the incomplete knowledge of expert. Thus. the purpose of this study is to present a method for representing the degree of the uncertainty contained in input data by applying fuzzy theory and incorporating it directly into the water quality modeling process. By using the method. the prediction on the future water quality level of Juam lake can be made that is more appropriate and realistic than the one made without taking uncertainty in account.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.882-895
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• 1997

Changes in the benthic communities have been studied to investigate the environmental effects before and after the construction of Shihwa Dike in the West coast of Korea. It is suggested that sequential changes in macrofaunal assemblages progressed in two sucressional directions. In the Shihwa lake under the influence of organic enrichment. First, the appearance of 'azoic tone' or 'grossly polluted zone' developed in the area of less than 6 m in depth resulted from the severe dissolved oxygen depletion due to the eutrophication from the increased organic loading. Second, the 'polluted zone' characterized by the proliferation of the opportunistic species in organically enriched area, was found in the vicinity of the industrial discharges and nearby fluvial inputs. This benthic community succession in the Shihwa lake seemed to be caused by the various ecological events such as an eutrophication in this organically enriched environment after construction of the dike and other physico-chemical parameters like salinity and dissolved oxygen in the bottom water, which may be influenced by the irregular surface water discharge and dilution by outer seawater inflow through the water gate of the dike. On the other hand, the benthic communities in the outside of the dike showed that the species richness was more than doubled and the abundance increased almost seven times more than that before the dike construction. This may be a typical characteristics of the initial phase in benthic eutrophication, suggesting that an increased organic input area may have been reponsible for this faunal change in the study area.

• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.945-950
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• 2007

The stormwater runoff from paved area are highly polluted because of particulate materials as well as metals from various vehicular activities. The Division of Road Maintenance in Ministry of Construction and Transportation was recently developed the Guidelines of Environment-kindly Road Maintenance. It is actually requiring the BMP construction to control the nonpoint source pollution as based on the TMDL program. This research is carried out in order to define the characteristics of stormwater runoff from the toll-gate of highways since 2006, which is actually one of the main pollutant sources of paved areas. This monitoring is the first phase work for establishing the treatment facilities in the toll-gates. The one of the main characteristics from toll-gate runoff is the first flush phenomenon containing lots of sediments and metal compounds at the beginning of a storm event. Usually it is used to determine the size of treatment facilities and to calculate the reduced pollutant mass in the facility. The research results shows that the mean EMC vaules for heavy metals are determined to $274.3{\mu}g/L$ for Cd, $1,273.4{\mu}g/L$ for Cr, $1,822.0{\mu}g/L$ for Cu, $6,504.9{\mu}g/L$ for Fe, $14,930.3{\mu}g/L$ for Pb, and $714.1{\mu}g/L$ for Zn. Also the metal mass loadings from the toll-gates are calculated using EMC, watershed area and storm duration.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.210-217
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• 2012

This study investigated the water quality of effluents from the wastewater treatment plants, located at the Gumi Complex 4, Gumi, and Wonpyong, in Gumi. DOC accounted for higher than 70% of TOC, and oxidation efficiencies, calculated from carbon, were 13~43% for BOD and 37~73% for CODMn, respectively. Based on the biological decomposition experiments, R-DOC account for higher than 70% of DOC, mostly being occupied by refractory organic matters. This indicated that the biodegradable organics occupied more proportions of organic loadings than the refractory organics. The effect of the organics from a discharge of a sewage treatment plant on rivers, Gumi industrial Complex 4, Gumi, and Wonpyong on lower streams of the Nakdong River were found to be 15%, 6% and 16% respectively. The ratio of 15% suggests that comparatively, no large portions of TOC loadings are occupied, but the problem is that the biodegradable organic matters occupy a lot more proportions than that of the refractory organic matters. Thus, it is highly estimated that the refractory organics can gradually increase the pollution level of organics and precursors of disinfection by-products to the down-stream water treatment plants.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.192-200
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• 2001

The event-based agricultural non-point source(AGNPS) pollution model was applied to estimate the loads of nitrogen and phosphorus in a stream draining small agricultural watersheds. Calibration and verification of the model were performed using observed data collected from rainfall events in the Imgo watersheds during 1997-1998. Parameter calibrations were made for the runoff curve number. The peak flow volumes in the watersheds were well reproduced by the modified model. Average deviation between observed and simulated values was 10%, and this match was confirmed by the coefficient of efficiency value of 0.97. The deviations tended to increase as the peak flows increased. The simulated total N concentrations in the stream water were fairly close to the measured values, and the coefficient of efficiency in the estimation was 0.93. However, there were relatively large variations between calculated and observed values of total P concentration, and the coefficient of efficiency in the estimation was 0.74. Any inaccuracies that arise in estimating runoff flow and nutrient loading can not be explained exactly and further adjustment and refinements may be needed for application of AGNPS in agricultural watersheds. With this restrictions in mind, it can be concluded that AGNPS can provide realistic estimates of nonpoint source nutrient yields.

• Atmosphere
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• v.27 no.2
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• pp.225-233
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• 2017

Korea has recently suffered from severe hazes, largely being long-range transported from China but frequently mixed with domestic pollution. It is important to identify the origin of the frequently-occurring hazes, which is however hard to clearly determine in a quantitative term. In this regard, we suggest a possible classification procedure of various hazes into long-range transported haze (LH), Yellow Sand (YS), and urban haze (UH), based on mass loading of fine particles, time lag of PM mass concentrations between two sites aligned with dominant wind direction, backward trajectory of air mass, and the mass ratio of PM2.5 to PM10. The analysis sites are Seoul (SL) and Baengnyeongdo (BN), which are distant about 200 km from each other in the west to east direction. Aerosol concentrations at BN are overall lower than those of SL, indicative of BN being a background site for SL. We found distinct time lag of PM2.5 and PM10 concentrations between BN and SL in case of both LH and YS, but the intensity of YS being stronger than LH. Time scale (e-folding time scale) of LH appears to be longer and more variable than YS, which implies that LH covers much larger spatial scale. In addition, we found linear and significant correlations between ${\tau}_a$ obtained from sunphotometer and ${\tau}_{cal}$ calculated from surface aerosol scattering coefficient for LH episodes, relative to few correlation between those for YS, which might be associated with transported height of YS being much higher than LH. Therefore surface PM concentrations for the YS period are thought to be not representative for vertical integrated amount of aerosol loadings, probably by virtue of decoupled structure of aerosol vertical distribution. Improvement of various hazes classification based on the current result would provide the public as well as researchers with more accurate information of LH, UH, and YS, in terms of temporal scale, size, vertical distribution of aerosols, etc.

• Journal of Environmental Science International
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• v.10 no.2
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• pp.119-127
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• 2001

The Keum river is one of the important river in Korea and has a drainage area of 9,873$\textrm{km}^2$. The Keum river is deepening pollution state due to development of the lower city and construction of a industrial complex. The water quality of the Keum river come to eutrophication state and belong to III grade of water quality standard. The concentration BOD in river is affected by the organic loading from a tributary and the algae biomass that largely happen to under eutrophication state. In the eutrophic water mass such as the Keum river, the autochthonous BOD was very important part for making a decision of water quality management, because it was accounted for majority of the total BOD. The purpose of this study was to survey the chatacteristics of water quality in summer and to estimate reaction coefficient. Also, we studied to correlationship between chlorophyll a and BOD(COD) for estimation of the autochthonous BOD. The correlationship between chlorophyll a and BOD(COD) were obtained through the culture experiment of phytoplankton in the laboratory. The results of this study may be summarized as follows ; The characteristics of water quality in summer were belong to III~IV grade of water quality standard as BOD and nutritive condition is very high. The BOD, ammonia nitrogen and phosphate loadings in Miho stream which inflowing untreated sewage from Chungju city was occupied with 64.07%, 26.36%, 46.08%, respectively. Maximum nutrient uptake (Vmax) was 0.4400$\mu$M/hr as substrate of ammonia nitrogen, 0.1652$\mu$M/hr as substrate of phosphate. Maximum specific growth rate ($\mu$max) was 1.2525$hr^{-1}$ as substrate of ammonia nitrogen, 1.5177$hr^{-1}$ as substrate of phosphate. The correlation coefficient between chlorophyll a and BOD by the culture experiment were found to be 0.911~0.935 and 0.942~0.947 in the case adding nutrient and no adding nutrient, respectively. The correlation coefficient between chlorophyll a and COD through the culture experiment were found to be 0.918~0.977 and 0.880~0.931 in the case adding nutrient and no adding nutrient, respectively. The autochthonous BOD(COD) was estimated to the relationship between BOD(COD) and chlorophyll a. The regression equation were found to be autochthonous BOD=(0.045~0.073)${\times}chlorophyll$ a and autochthonous $COD=(0.137~0.182){\times}chlorophyll$ a.

• KSBB Journal
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• v.22 no.2
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• pp.97-101
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• 2007

This study was performed to examine the availability of anaerobic digestion of the remainders caused by bacterial cellulose production process using food wastes. They maybe to be considered as others second pollution sources. Thus, this study was targeted to minimize content of organic material and to obtain more energy in those remnants using two-phase UASB reactor. The working volume of first hydrolysis fermentor was 35 L (total 55 L) and the second methane fermentor was 40 L (total 50 L). The organic loading rate of hydrolysis fermentor was 3 g-VS/L${\cdot}$day and 25,000 ppm of $COD_{cr}$ for methane fermentor. The hydraulic retention time was 18 days for hydrolysis reactor and 33 days for methane reactor. The hydrolysis reactor and methane reactor were performed at 35, 40$^{\circ}C$ respectively. For the efficient stable performance, the composition of organic wastes at each stage was as follow; Food waste with bacterial culture remnants (1 : 1), bacterial cellulose remnants, bacterial cellulose culture remnants with food wastes saccharified solids (1 : 1). When the anaerobic digestion was performed stably at each stage, the COD removal efficiency was 88, 90, 91 % respectively. At this time, methane production rate was 0.26, 0.34, $0.32m^3\;CH_4/kg-COD_{remove}$. As well as the values of anaerobic digestion at third stage were more higher than values of anaerobic digestion using food wastes. It is clearly to say that the food wastes zero-emission system constructed in our lab is more efficient way to treat and reclaim food wastes.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.195-202
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• 2020

The production of larger of ships is a survival strategy for global shipping companies to pursue the economics of scale. According to this strategy, to respond to this situation, many containers are loading/unloading simultaneously in the hub port. Additionally, the container terminals are promoting the introduction of automation to expand the terminal facilities and increase efficiency/productivity of the container yards. European ports have introduced automation to address rising labor costs and shortages of labor. Recently, the construction of fully automated container terminals is increasing in the United States and China to resolve problems such as the slow growth of the global economy, the emergence of large ships, air pollution, and safety accidents. Domestic ports are at an early stage compared to the world's advanced container terminals, and countermeasures are being prepared to respond to the changing ports. However, research on the recognition difference analysis that examines the opinions of stakeholders is insufficient. As a result of analyzing the recognition among the groups, it was found that container terminal operators reduced labor costs, improved shipping services for shipping companies, prevented safety accidents for port union labor, and increased service for port authority and government agencies. Thus, to closely examine the perception among the groups, one-way ANOVA was performed, and then the implications were deduced as the basic data for the smooth introduction of automation.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.2
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• pp.1-14
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• 2019

In rural areas, composting is a source of non-point pollutants. However, as the quantitative distribution and loading have not been estimated, it is difficult to determine the effect of composting on stream water quality. In this study, composting datum acquired by unmanned aerial vehicle(UAV) was verified by using terrestrial LiDAR, and the management status and load change of the composting was investigated by UAV with manual control flight, thereby obtaining the basic data to determine the effect on the water system. As a result of the comparative accuracy assessment based on terrestrial LiDAR, the difference in the digital surface model(DSM) was within 0.21m and the accuracy of the volume was 93.24%. We expect that the accuracy is sufficient to calculate and utilize the composting load acquired by UAV. Thus, the management status of composting can be investigated by UAV. As the total load change of composting were determined to be $1,172.16m^3$, $1,461.66m^3$, and $1,350.53m^3$, respectively, the load change of composting could be confirmed. We expect that the results of this study can contribute to efficient management of non-point source pollution by UAV.