• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.143-157
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• 2021

International organizations such as the World Health Organization, the Organization for Economic Development and Cooperation, and major developed countries recognize the seriousness of air pollution. International organizations such as the International Maritime Organization have also implemented various regulations to reduce air pollution from ships. In line with this international trend, the government has also enacted a special law on improving air quality in port areas, and is making efforts to reduce air pollution caused by ports. The purpose of the Special Act is to implement comprehensive policies to improve air quality in port areas. This study sought to identify the emissions of each source of air pollutants originating from the port and prepare basic data on setting the policy priorities. To this end, the analysis was conducted in six categories: ships, vehicles, loading and unloading equipment, railways, unloading/wild ash dust, road ash dust, and the methodology presented by the European Environment Agency(EEA) and the United States Environmental Protection Agency(EPA). The pollutants subject to analysis were analyzed for carbon monoxide(CO), nitrogen oxides (NOX), sulfur oxides(SOX), total airborne materials(TSP), particulate matter(PM10, PM2.5), and ammonia(NH3). The analysis showed a total of 7,122 tons of emissions. By substance, NOX accounted for the largest portion of 5,084 tons, followed by CO (984 tons), SOX (530 tons), and TSP (335 tons). By source of emissions, ships accounted for the largest portion with 4,107 tons, followed by vehicles with 2,622 tons, showing high emissions. This proved to be the main cause of port air pollution, with 57.6% and 36.8% of total emissions, respectively, suggesting the need for countermeasures against these sources.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.137-145
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• 2013

This study was performed at 2 sites of Nak-Dong River to investigate the changes of nitrifiers depending on the presence and absence of organic pollutants (due to the effluents of domestic wastewater treatment plant, WWTP). Conventional chemical parameters such as T-N, $NH_4$-N, $NO_2$-N, $NO_3$-N were measured and the quantitative nitrifiers at the 2 sites were analyzed comparatively by fluorescent in situ hybridization (FISH) with NSO190 and NIT3, after checking the presence of gene amoA of ammonia oxidizing bacteria (AOB) and 16S rDNA signature sequence for Nitrobacter sp. that belongs to nitrite oxidizing bacteria (NOB). Also ${\alpha}{\cdot}{\beta}{\cdot}{\gamma}$-Proteobacteria were detected using FISH to get a glimpse of the general bacterial community structure of the sites. Based on the distribution structure of the ${\alpha}{\cdot}{\beta}{\cdot}{\gamma}$-Proteobacteria and the measurement of nitrogen in different phases, it could be said that the site 2 was more polluted with organics than site 1. Corresponding to the above conclusion, the average numbers of AOB and NOB detected by NSO160 and NIT3, respectively, at site 2 [AOB, $9.3{\times}10^5$; NOB, $1.6{\times}10^6$ (cells/ml)] was more than those at site 1 [AOB, $7.8{\times}10^5$; NOB, $0.8{\times}10^6$ (cells/ml)] and also their ratios to total counts were higher at site 2 (AOB, 27%; NOB, 34%) than those at site 1 (AOB, 18%; NOB, 23%). Thus, it could be concluded that the nitrification at site 2 was more active due to continuous loading of organics from the effluents of domestic WWTP, compared to site 1 located closed to raw drinking water supply and subsequently less polluted with organics.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.12
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• pp.696-704
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• 2015

This study was carried out to evaluate the optimum operational condition of Semi-continuously Fed and Mixed Reactor (SCFMR) to treat the dairy cow manure and saw dust mixture. Step-wise increase in organic loading rates (OLRs) or decrease in hydraulic retention times (HRTs) were utilized until the biogas volume became significantly decreased at mesophilic temperature ($35^{\circ}C$). The optimum operating condition of the SCFMR fed with TS 13% dairy cow manure and saw dust mixture was found to be an HRTs of 25 days and its corresponding OLRs of $4.45kg\;VS/m^3-day$. At this condition the biogas and methane production rates were 1.44 v/v-d and 1.12 v/v-d (volume of biogas per volume of reactor per day), respectively and the TVS removal efficiency of 37% was achieved. The successful operation with such a high OLR was due to the high reactor alkalinity concentration of 14,500~15,600 mg/L as $CaCO_3$ as a result of the characteristic of the original substrate, dairy cow manure and saw dust mixture whose alkalinity was more than 8,000 mg/L as $CaCO_3$. The parameters for the reactor stability, the ratios of volatile acids and alkalinity concentrations (V/A) and the ratio of propionic acid and acetic acid concentrations (P/A) appeared to be 0.11 and 0.43, respectively, that were greatly stable in operation. Free ammonia toxicity was not experienced due to the long term acclimation by the reactor TS content ranged 7.2~10.4% during the entire operational period.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.147-152
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• 2015

Nitrogen (N) loading from domestic, agricultural and industrial sources can lead to excessive growth of macrophytes or phytoplankton in aquatic environment. Many studies have used nitrogen stable isotope ratios to identify anthropogenic nitrogen in aquatic systems as a useful method for studying nitrogen cycle. In this study to evaluate the precision and accuracy of Kjeldahl processes, two reference materials (IAEA-NO-3, N-1) were analyzed repeatedly. Measured the ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values of IAEA-NO-3 and IAEA-N-1 were $4.7{\pm}0.2$‰ and $0.4{\pm}0.3$‰, respectively, which are within recommended values of analytical uncertainties. Also, we investigated spatial patterns of ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ in effluent plumes from a waste water treatment plant in Han River, Korea. ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values are enriched at downstream areas of water treatment plant suggesting that dissolved nitrogen in effluent plumes should be one of the main N sources in those areas. The current study clarifies the reliability of Kjeldahl analytical method and the usefulness of stable isotopic techniques to trace the contamination source of dissolved nitrogen such as nitrate and ammonia.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.184-194
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• 2021

Since the construction of a dike in 1983, the water quality in the Bunam Lake has continued to deteriorate due to algal bloom caused by agricultural nutrient loading. Therefore, we evaluated the change in water quality and phytoplankton ecological characteristics in Bunam Lake and Cheonsu Bay, Korea. Water temperature, salinity, dissolved oxygen, chemical oxygen demand (COD), chlorophyll, and phytoplankton community were surveyed in April during the dry season and in July during the rainy reason. As a result, during the dry period, phytoplankton proliferated greatly and stagnated in the Bunam Lake while a very high population of cyanobacteria Oscillatoria spp. (8.61×10⁷ cells L^-1) was recorded. Most of the nutrients, except, nitrate and nitrite, were consumed due to the large growth of phytoplankton. However, during the rainy period, concentrations of ammonia, phosphate, silicate, nitrate, and nitrite, were very high towards the upper station due to the inflow of fresh water. Cyanobacteria Oscillatoria and Microcystis spp. were dominant in the Bunam Lake during the rainy period. Even in the Cheonsu Bay, cyanobacteria dominated due to the effect of discharge and diatoms, such as, Chaetoceros spp. and Eucampia zodiacus, which also proliferated significantly due to increased levels of nutrients. Since the eutrophication index was above 1 in Bunam Lake, it was classified as eutrophic water and the Cheonsu Bay was classified as eutrophic water only during the rainy season. In addition, a stagnant seawater-derived hypoxia water mass was observed at a depth of8m in the Bunam Lake adjacent to the tide embankment and the COD concentration reached 206 mg L^-1 in the bottom layer at B3. Based on this result, it is considered that the water quality will continue to deteriorate if organic matters settle due to continuous inflow of nutrients and growth of organisms while the bottom water mass is stagnant.