• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.116-118
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• 2023

In recent years, the need for economical and sustainable ship routing has emerged due to the enforced regulations on environmental issues. Despite the development of weather forecasting technology, maritime accidents by rough waves have continued to occur due to incorrect weather forecasts. In this study, onboard measurements are conducted to observe the acutal situation on merchant ships in operation encountering rough waves. The types of measured data include information related to navigation (Ship's position, speed, bearing, rudder angle) and engine (engine revolutions, power, shaft thrust, fuel consumption), weather conditions (wind, waves), and ship motions (roll, pitch, and yaw). These ship experiments was conducted to 28,000 DWT bulk carrier, 63,000 DWT bulk carrier, 20,000 TEU container ship, and 12,000 TEU container ship. The actual ship experiment of each ship is intended to acquire various types of data and utilize them for multi-objective studies related to ship operation. Additionally, in order to confirm the sea conditions, the directional wave spectrum was reproduced using a wave simulation model. Through data collection from ship experiments and wave simulations, various studies could be proceeding such as the measurement for accurate wave information by marine radar and analysis for cargo collapse accidents. In addition, it is expected to be utilized in various themes from the perspective of safety and efficiency in ship operation.

• Journal of Wetlands Research
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• v.6 no.1
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• pp.133-147
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• 2004

Environmental quality(water and sediment) was analyzed in the tidal flat of Saemangum of Jeonbuk Province, the west coast of Korea, using the 101 sediment samples and 69 water samples collected in September 4~13, 2001. Major water quality parameters with the means of 69 surface water samples are as follows; $25.51{\pm}0.68^{\circ}C$ for water temperature, $29.88{\pm}5.01$ for salinity, $1.40{\pm}0.78mg/L$ for COD, $0.352{\pm}0.417mg/L$ for DIN, and $0.027{\pm}0.023mg/L$ for phosphate, respectively. Higher values were found at the subestuary of Dongjin and Mangyung River, and lower values at the Saemangum embayment and Gomso Bay. There was a significant negative correlation between salinity and the other water quality parameters(p<0.0001) such as COD, nutrients, SS and N/P. This correlation suggested that the major pollution sources be from terrestrial inputs through tributaries in this area. Principal component analysis clearly revealed a spatial variation of water quality; stations with higher values of nutrients and COD located subestuary of tributaries. 14 sediment quality parameters including 8 trace metals were measured using the 101 surface sediment samples. Average values for the parameters are as follows; Al $2.28{\pm}0.92%$, Cd $0.61{\pm}0.27ppm$, Cu $8.95{\pm}4.06ppm$, Fe $1.19{\pm}0.37%$, Mn $182.31{\pm}77.45ppm$, Ni $10.83{\pm}4.97ppm$, Pb $15.20{\pm}4.35ppm$, Zn $41.34{\pm}34.62ppm$, COD $2.68{\pm}1.85mg/g\;dry$, AVS $0.04{\pm}0.08mg/g\;dry$, IL $1.29{\pm}1.08%$, water content $24.11{\pm}4.49%$, TN $0.02{\pm}0.02%$, TC $0.22{\pm}0.30%$. Spatial variations of sediment quality were not clear as water quality. Some higher values were found at the subestuary of Gum River and lower values at the other area. There was a significant positive correlation between the heavy metal concentrations and organic materials within the sediment(p<0.05). Enrichment factors showed the ranges of 1~2 for most of the metals in the sediment except zinc(1~6), indicating no serious exogenous input of heavy metals in the study area. Also, the heavy metal concentrations in the sediment were within the ranges found at the natural marine environments.

• Analytical Science and Technology
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• v.23 no.4
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• pp.371-382
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• 2010

TSP and PM2.5 atmospheric aerosols have been collected at Gosan site of Jeju Island, and their compositions were analyzed to understand the pollution characteristics. The composition ratios of nss (non-sea salt)-$SO_4^{2-}$ and $NH_4^+$ were higher in Gosan site than those in other Korean background and urban sites. However the composition ratio of $NO_3^-$ was conversely lower in Gosan site. From the study of aerosol components according to particle sizes, the anthropogenic nss-$SO_4^{2-}$, $NO_3^-$ and $NH_4^+$ components were mostly existed in the fine particles. But the nss-$Ca^{2+}$, $Na^+$, $Cl^-$ and $Mg^{2+}$ originated from soil and marine sources were distributed relatively in the coarse particles. In the seasonal comparison, the concentrations of nss-$Ca^{2+}$, Al, Fe, Ca and $NO_3^-$ increased in spring season, and nss-$SO_4^{2-}$ showed higher concentration in summer and spring seasons. Based on the factor analysis, the atmospheric aerosols in Gosan site have been found to be influenced largely by anthropogenic sources, and next by marine and soil sources. The backward trajectory analyses showed that the concentrations of nss-$SO_4^{2-}$, $NO_3^-$, Pb and nss-$Ca^{2+}$ increased when the air mass moved from Chinese continent to Jeju area. On the other hand, their concentrations decreased when the air mass moved in from the North Pacific Ocean.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.651-660
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• 2007

Acid drainage has been recognized as an environmental concern in abandoned mine sites for long time. Recently, the environmental and structural damage by acid drainage is a current issue in construction sites in Korea. Here, the author introduces the type of damages by acid drainage in construction sites and emphasizes the importance of geoscience discipline in solving the problem. Metasedimentary rock of Okcheon group, coal bed of Pyeongan group, Mesozoic volcanic rock. and Tertiary sedimentary and volcanic rocks are the major rock types with a high potential for acid drainage upon excavation in Korea. The acid drainage causes the acidification and heavy metal contamination of soil, surface water and groundwater, the reduction of slope stability, the corrosion of slope structure, the damage on plant growth, the damage on landscape and the deterioration of concrete and asphalt pavement. The countermeasure for acid drainage is the treatment of acid drainage and the prevention of acid drainage. The treatment of acid drainage can be classified into active and passive treatments depending on the degree of natural process in the treatment. Removal of oxidants, reduction of oxidant generation and encapsulation of sulfide are employed for the prevention of acid drainage generation.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.141-160
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• 2018

In this paper, to analyze the perception and response strategy of Korean ship owners on Global Sulphur Cap 2020, examined the IMO environmental regulation status focusing on MARPOL Annex VI regulation about air pollution prevention, technological measures to reduce SOx emission, shipping industry and management status of Korean ship owners. First of all, the questionnaire was conducted for Korean ship owners after selecting the evaluation factors. The purpose of this study was to investigate the difference of the perception and response strategy of Korean ship owners by corporation size and main vessel type using frequency and cross analysis. It is confirmed that various researches on SOx emission reduction have been carried out from various points of view at home and abroad. In this study, existing studies related to technical factors for regulatory response and economics analysis were examined and evaluation factors were selected. As a result of analysis, it is found that large-sized shipping companies are more prepared for regulatory response than small and medium-sized bulk carrier owners. There were similar perception and the direction of response strategy about the impacts by corporation size and main vessel type. In about two years to be implemented in 2020, It is necessary to find an appropriate response strategy based on the support policy of the government and related organizations and the systematic analysis of the ship owners. Through this study, although the difference between the perception and response strategy of the ship owners by corporation size and main vessel type was understood, it was found that there were limitations on specific response strategy and corporate data collection. In future research, we should overcome the limitations of this study and conduct an in-depth study.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.5-13
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• 2022

The current environmental problem is that environmental pollution is accelerating due to the generation of large amounts of waste and indiscriminate consumption of energy. Fossil fuels, a representative energy production fuel, are burned in the process of producing energy, generating a large amount of greenhouse gases and eventually causing climate change. In addition, the amount of waste generated worldwide is continuously increasing, and environmental pollution is occurring in the process of waste treatment. One of the methods for simultaneously solving these problems is the energy recovery from and reduction of organic wastes. Sewage sludge generated in sewage treatment plants has been treated in various ways since ocean disposal was completely prohibited, but the amount generated has been continuously increasing. Since the sewage sludge contains a large amount of organic materials, it is desirable to recover energy from the sewage sludge and reduce the final discharged waste through anaerobic digestion. However, most of the excess sludge is a mass of microorganisms used in sewage treatment, and in order for the excess sludge to be anaerobically digested, the cell walls of the microorganisms must be destroyed first, but it takes a lot of time to destroy the cell walls, so high rates of biogas production and waste reduction cannot be achieved only by anaerobic digestion. Therefore, the pre-treatment process of solubilizing excess sludge is required, and the thermal solubilization process is verified to be the most efficient among various solubilization methods, and high rates of biogas production and waste reduction can be achieved by anaerobic digestion after destroying cell walls the thermal solubilization process. In this study, when pretreating TS 10% thickened excess sludge through a thermal solubilization system, a study was conducted on solubilization characteristics according to retention time and operating temperature variables. The experimental variables for the retention time of the thermal solubilization system were 30 minutes, 60 minutes, 90 minutes, and 120 minutes, respectively, while the operating temperature was fixed at 160℃. The soulbilization rates calculated through TCOD and SCOD derived from the experimental results increased in the order of 12.11%, 20.52%, 28.62%, and 31.40%, respectively. And the variables according to operating temperature were 120℃, 140℃, 160℃, 180℃, and 200℃, respectively, while the operating retention time was fixed at 60 minutes. And the solubilization rates increased in the order of 7.14%, 14.52%, 20.52%, 40.72%, and 57.85%, respectively. In addition, TS, VS, T-N, T-P, NH₄⁺-N, and VFAs were analyzed to evaluate thermal solubilization characteristics of thickened excess sludge. As a result, in order to obtain 30% or more solubilization rate through thermal solubilization of TS 10% thickened excess sludge, 120 minutes of retention time is required when the operating temperature is fixed to 160℃, and 170℃ or more of operating temperature is needed when the operating time is fixed to 60 minutes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.259-264
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• 2001

Typhoon and neap tide on Cochlodinium polykrikoides bloom and water temperature on disappearance of C. polykrikoides bloom were investigated to elucidate the outbreak mechanism of C. polykrikoides blooms at Naro and Namhae coastal area in South Sea of Korea. The first observation of C. polykrikoides blooms were observed when thermocline was disappeared by typhoon, tide, etc. The first blooms of C. polykrikoides were observed on neap tide or before one day from neap tide in 1996-1998 and 2000. However, thermocline was disappeared by typhoon in 1994 and 1999, the first blooms were observed early 12-30 day than 1996-1998 and 2000. The main reason of disappearance of C. polykrikoides blooms after typhoon on 1997-2000 seems to be other environmental change by typhoon rather than low water temperature. In the future, the first C. polykrikoides bloom will be appear around the first neap tide of latter part of August with breaking down of thermocline, but if the thermocline be collapsed by typhoon in July, the C. polykrikoides bloom will be appear at beginning of August. The outbreak of C. polykrikoides blooms will be explain as follows: The vegetative cells, which was germinated by environmental change or already exist in surface water at low level, input to the surface water, and then nutrients and trace metals which were suppled from out side of C. polykrikoides bloom area inflow to surface. The vegetative cells are growth by the nutrients and trace metals at suitable environmental conditions e.g. water temperature, salinity, and sufficient light.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.262-269
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• 2012

We investigated the concentration levels and evaluated the distributions of 17 polychlorinated dibenzo-p-dioxins and furans(PCDD/Fs), 12 dioxin-like polychlorinated biphenyls(DLPCBs) and 24 polybrominated diphenyl ethers (PBDEs) in sediment and organism from various culturing grounds in Korean coast. The levels of PCDD/Fs, DLPCBs, and PBDEs in sediment samples ranged from 0.03 to 2.9(Mean${\pm}$SD, $1.2{\pm}0.89$) pg $WHO_{2005}$-TEQ $g^{-1}$ dry weight(dw), ND(not detected) to 1.1($0.09{\pm}0.19$) pg $WHO_{2005}$-TEQ $g^{-1}$ dw, and ND to 16.6($2.96{\pm}3.53$) ng $g^{-1}$ dw, respectively. Also, the levels of PCDD/Fs, DLPCBs, and PBDEs in culturing organisms ranged from ND to 0.24($0.07{\pm}0.06$) pg $WHO_{2005}$-TEQ $g^{-1}$ wet weight(ww), ND to 0.11($0.04{\pm}0.04$) pg $WHO_{2005}$-TEQ $g^{-1}$ ww, and 0.05 to 0.29($0.13{\pm}0.06$) ng $g^{-1}$ ww, respectively. The levels of total dioxins(PCDD/Fs+DLPCBs) and PBDEs in sediments from East and South sea were four to seven times higher than those from West sea. PCDD/Fs had dominant contribution(mean, 94%) for TEQ concentration in sediment, whereas relatively higher contribution of DLPCBs(33%) were shown in culturing organism than sediment. BDE209 was a dominant congener in both matrix. The concentrations of PCDD/Fs, DLPCBs and PBDEs were in decreasing trends in Korea coasts compared to previous results.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.2
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• pp.81-92
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• 2001

According to analyses of high-resolution seismic profiles (air gun, sparker, and SBP) and a deep-drill core(YSDP 105) in the mid-eastern Yellow Sea, stratigraphic and geoacoustic models have been established and seismo-acoustic modeling has been fulfilled using ray tracing of finite element method. Stratigraphic model reflects seismo-, litho-, and chrono-stratigraphic sequences formed under a significant influence of Quaternary glacio-eustatic sea-level fluctuations. Each sequence consists of terrestrial to very-shallow-marine coarse-grained lowstand systems tract and tidal fine-grained transgressive to highstand systems tract. Based on mean grain-size data (121 samples) of the drill core, bulk density and P-wave velocity of depositional units have been inferred and extrapolated down to a depth of the recovery using the Hamilton's regression equations. As goo-acoustic parameters, the 121 pairs of bulk density and P-wave velocity have been averaged on each unit of the stratigraphic model. As a result of computer ray-tracing simulation of the subsurface strata, we have found that there are complex ray paths and many acoustic-shadow zones owing to the presence of irregular layer boundaries and low-velocity layers.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.1
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• pp.1-12
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• 2004

The summer distribution of $Cha-{alpha}$ and physical processes for simulating outbreak region of red tide were estimated by the Eco-Hydrodynamic model in Chinhae Bay. As a result of simulation of surface residual currents, the southward flow come in contact with the northward flow at the inlet and western part of bay in case of windlessness and below wind velocity 2 m/sec. As wind velocity increases, the velocity and direction of currents were fairly shifted. The predicted concentration of $Cha-{alpha}$ exceeded 20 mg/㎥ in Masan and Haengam Bays, and most regions were over 10 mg/㎥, which meant the possibility of red tide outbreak. From the results of the contributed physical processes to $Cha-{alpha}$, accumulation sites were distributed at the northern part of Kadok channel, around the Chilcheon island, the western part of Kajo island and some area of Chindong Bay. On the other hand, inner parts of the study area such as Masan Bay were estimated as the sites of strong algal activities. Masan and Haengam Bay are considered as the initial outbreak region of red tide by the modeling and observed data, and then red tide expanded to other areas such as physical accumulation region and western inner bay, as depending on environmental variation. The increase of wind velocity led to decrease of $Cha-{alpha}$ and enlargement of accumulation region. The variation of intensity of radiation and sunshine duration caused to rapidly fluctuation of $Cha-{alpha}$: however, it was not largely affected by the variation of pollutant loads from the land only.