• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.1
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• pp.68-77
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• 2003

The Water quality of Namdae and Yeongok stream, located in the Kangnung City, and pollutants discharged to the east sea of Korea were investigated during april to November 2002 in order to understand the costal pollution phenomena. The water qualify grade of Namdae stream vary between II and V of water standard. On the other hand, that of Yeongok Stream is keeping I or II. The temporal and spacial variation of Namdae stream are higher than Yeongok stream. The water pollutants discharged to the east sea of Korea from Yeongok stream are lower 15.5 times for BOD, 2.6 times for COD, 1.7 times for T-N, 6.9 times for T-P than from Namdae stream, of which water flux are 1.4 times higher and contain much more of pollutants than Yeongok stream. It may have some effect on the costal ecosystem according to their pollutant flux.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.845-851
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• 1998

In order to manage the water quality from the flowing streams in Cheju Island, the characteristics of water quality was investigated from August, 1996 to May, 1997 and the pollutant loadings for future were estimated from the watershed at each stream. Comparing the mean concentrations of each water quality with the criterion of water quality in river, it was under I class except for Changgo Stream, for DO, under I class at the whole station for SS and under II class for BOD. As the pollutant loadings at each stream in 2020 is compared with those in 1996, the estimated results are as follows : 1) for BOD, 59% at Donghong Stream, 24% at Yeonoe Stream, 44% at Ohngpo Stream and 57% at Changgo Stream. 2) for T-N, 91% at Donghong Stream, 76% at Yeonoe Stream, 63% at Ohngpo Stream and 89% at Changgo Stream. 3) for T-P, 69% at Donghong Stream, 42% at Yeonoe Stream, 45% at Ohngpo Stream and 73% at Changgo Stream. The point source loadings discharged through combined sewer could be treated at sewage treatment plant. However, the expected slow decreasing rate of BOD, T-N, and T-P loadings is due to the part of untreated nonpoint source loadings. Nonpoint source loading overflow typically occurs when the flow of stormwater combined with sewage exceeds the capacity of the interceptor sewers. Since most of the sewers used in Cheju Island are the combined sewers, the combined overflow sewage is bypassed into the receiving water area after a rainstorm. Therefore, a means to control nonpoint source loadings should be considered for the river and marine water quality management.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.468-472
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• 2015

Recently, there has been increasing interest in the efficient use of energy due to policies related to the reduction of greenhouse gas. This paper suggests a highly efficient sea water cooling system for the load-dependent control of a seawater pump depending on the load, to improve energy efficiency of the warship. This study models the propulsion diesel engine and simulation reflecting the characteristics of the warship operation state that checked the performance of high efficiency sea water cooling system. The simulation results revealed the cooling system of high efficiency with energy savings of approximately 53% compared to the existing cooling systems. These results can be used to improve the performance of the cooling system of the warship propulsion diesel engine in the future.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.2
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• pp.28-37
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• 2003

We investigated water quality, salinity, nutrients, SS, COD and Chlorophyll-a concentrations in the seawater of the Mokpo costal area, southwestern coast of Korea. Seawater samples at 25 stations were collected in July 20, 25 and September 3, 2002 after a strong rain event. The distributions nutrients in seawater were analyzed using an method of sea water analysis presented by the ministry of Maritime Affairs and Fisheries of Korea. The sampling sites were categorized into the inner and outer harbour based on salinity distribution and difference of nutrients distributions was evidence between these two zones. Nutrients and SS inflow and distributed in the inner harbour by the discharged freshwater from Youngsan river during strong rainfall whereas they were distributed in seawater of outer harbour by natural processes in general coastal area.

• Journal of Environmental Science International
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• v.15 no.9
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• pp.819-827
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• 2006

We study on the dynamic interaction with a simulated physical-biological coupled model response to nutrient reduction scenario in Jinhae Bay. According to the low relative errors, high regression coefficients of COD and DIN, and realistic distribution in comparison to the observation, our coupled model could be applicable for assessing the marine ecosystem response to nutrient input reduction in Jinhae Bay. Due to the new construction and expansion of sewage treatment plant from our government, we reduce 50% nutrient inputs near Masan Bay and sewage treatment plant. COD achieves Level II in Korea standard of the water quality from the middle of the Masan Bay to all around Jinhae Bay except the inner Masan Bay remaining at Level III. When our experiment reduces 50% nutrient inputs near Masan Bay and Dukdong sewage treatment plant simultaneously, COD decreases to about 0.1-1.2 mg/L $(128^{\circ}30'{\sim}128^{\circ}40'\;E,\;35^{\circ}05'{\sim}35^{\circ}11'\;N)$. The COD from the middle of the Masan Bay to Jinhae Bay achieves Level II.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.437-441
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• 2003

This research investigated the effects of processing conditions and natural antimicrobial materials on quality of freeze-dried, seasoned and roasted Alaska pollack (Theragra chalcogramma). The optimum dipping time and moisture contents of freeze-dried Alaska pollack were 1 sec in $1\%$ salt solution, $48.6\%$ respectively. The freeze-dried, seasoned and roasted Alaska pollack product showed high sensory value. As sterilization time increased over 30 mins in water bath at $100^{\circ}C$ the browning degree of the freeze-dried, seasoned and roasted Alaska pollack product increased. Among various antibrowning agents, $3\%$ corn starch was better in preventing browning than sporix treatment. The freeze-dried, seasoned and roasted Alaska pollack product added with lactate Ca and catechin had the antimicrobial, and the VBN contents of the product showed low level.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.468-482
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• 2016

To understand variations in the seawater quality of Asan Bay over four seasons form December 2011 to February 2013, we applied two methods: an in-situ observation of water quality and a comparison study of nutrient budgets among three parts (No. 1, 2, and 3) of Asan Bay. We found a significantly high nutrient concentration in the central part of the bay (No. 2) in July 2012 both in the mass balance study and in situ observation. We presumed the source of these nutrients to be both benthic effluence from old dam reservoirs and incompletely-treated municipal waste-water. This elevated nutrient concentration in the central part of Asan Bay (No. 2) expended to off-shore area and eventually triggered an intense Chl-a concentration in Asan Bay. Based on this result, we suggest improved waste-water quality control around the drainage area of Asan Bay.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.453-460
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• 2005

Since late 1970s, water quality monitoring had been performed in Korea by various agencies according to their own needs and objectives. Lacking of consistency in principles, such diverse operation has been producing difficulties in management of information on water quality parameters. These difficulties resulted from the fact that the expansion of monitoring networks had been based not on systematic methodology with considerations on scientifically established planning objectives but on personal experiences and subjective judgments in locating monitoring stations. This study aimed, therefore, to develop a selection methodology for locating monitoring stations to provide various informations on water quality to satisfy various monitoring objectives such as understanding short and long term trends of water quality, monitoring violations to water quality standards, identifying external causes and sources affecting water quality changes, supporting utilization of water resources, examining short-term variations in water quality through a concentrated investigation, estimating pollution loads from each unit watershed, supporting water quality modeling, and establishing informative systems for water resources management. Also, we applied the proposed methodology and presented an improved expansion plan for water quality monitoring networks in the Han River.

• Ocean and Polar Research
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• v.43 no.4
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• pp.229-243
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• 2021

Quality control (QC) to process observed time series has become more critical as the types and amount of observed data have increased along with the development of ocean observing sensors and communication technology. International ocean observing institutions have developed and operated automatic QC procedures for these observed time series. In this study, the performance of automated QC procedures proposed by U.S. IOOS (Integrated Ocean Observing System), NDBC (National Data Buy Center), and OOI (Ocean Observatory Initiative) were evaluated for observed time-series particularly from the Yellow and East China Seas by taking advantage of a confusion matrix. We focused on detecting additive outliers (AO) and temporary change outliers (TCO) based on ocean temperature observation from the Ieodo Ocean Research Station (I-ORS) in 2013. Our results present that the IOOS variability check procedure tends to classify normal data as AO or TCO. The NDBC variability check tracks outliers well but also tends to classify a lot of normal data as abnormal, particularly in the case of rapidly fluctuating time-series. The OOI procedure seems to detect the AO and TCO most effectively and the rate of classifying normal data as abnormal is also the lowest among the international checks. However, all three checks need additional scrutiny because they often fail to classify outliers when intermittent observations are performed or as a result of systematic errors, as well as tending to classify normal data as outliers in the case where there is abrupt change in the observed data due to a sensor being located within a sharp boundary between two water masses, which is a common feature in shallow water observations. Therefore, this study underlines the necessity of developing a new QC algorithm for time-series occurring in a shallow sea.