• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.753-770
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• 2006

In urban areas, groundwater pollution is heavily affected by urbanization with land use types. This study aims to characterize groundwater quality and contamination in Sasang industrial area of Busan Metropolitan City where metalworking, machinery and footwear factories are located. Busan Metropolitan City is the highest in the utilization of groundwater resources among the metropolitan cities in Korea. $K^+,\;Na^+,\;Ca^{2+},\;Mg^{2+},\;Cl^-,\;SO_4^{2-}\;and\;HCO_3^-$ concentrations, and electrical conductivity (EC), total dissolved solids (TDS) and salinity are high in the areas near the Nakdong River. The results are attributed to the influence of salt water which intruded into the coastal sediments during sedimentation. In addition, the dominant chemical type of Ca-Cl indicates the influence of salt water in the geological formations as well as anthropogenic pollution. $SiO_2$ ion is interpreted to originate from both water-silicate mineral reactions and the decomposition of cement concretes. Trichloroethylene (TCE) was detected at 12 sites of total 18 sites. However, tetrachloroethylene (PCE) was detected at f sites and 1.1.1-trichloroethane (TCA) at 3 sites. According to the factor analysis, factor 1 was explained by 49.8%, factor 2 19.8%, and factor 3 11.0% with total 80.6% explanation. pH, TDS, salinity, $Ca^{2+},\;K^+,\;Mg^{2+},\;Na^+,\;Al^{3+},\;As^{3+},\;Cl^-\;and\;Fe^{2+}$ were positively highly loaded to factor 1. The chemical components loaded to factor 1 represent the chemical characteristics of both industrial pollution and influence by salt water. Based on the cluster analysis and distribution pattern of chemical components, the concentration of $Na^+,\;Ca^{2+},\;Cl^-,\;SO_4^{2-}\;K^+,\;and\;Mg^{2+}$ is high in the riverside area of the Nakdong River composed of coastal sediments that is influenced by salt water. The downstream area of the Hakjang Stream is judged to be affected by both salt water and artificial pollution. The other part of the study area is interpreted by anthropogenic pollution.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.212-221
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• 2011

Wastewater treatment plants (WWTPs) are required to meet the reinforced discharge standards which are differentiated as 0.2, 0.3 and 0.5 mg-TP/L for the district I, II and III, respectively. Although most of WWTPs are operating advanced biological phosphorus removal system, the supplementary phosphorus treatment facility using chemical addition should be required almost at all WWTPs. Therefore, water quality data from several exemplary full-scale plants operating phosphorus treatment process were analyzed to evaluate the reliability of removal performance. Additionally, a series of jar tests were conducted to find optimal coagulants dose for phosphorus removal by chemical precipitation and to describe characteristics of the reaction and sludge production. Chemical costs and the increasing sludge volume in physicochemical phosphorus removal process were estimated based on the results of jar tests. The minimum coagulant (aluminium sulfate and poly aluminium chloride) doses to keep TP concentration below 0.5 and 0.2 mg/L were around 25 and 30 mg/L (as $Al_2O_3$), respectively, in the mixed liquor of activated sludge. In the tertiary treatment facility, relatively lower coagulant doses of 1/12~1/3 the minimum doses for activated sludge were required to achieve the same TP concentrations of 0.2~0.5 mg/L. Increase in suspended solids concentration due to chemical precipitates in mixed liquor was estimated at 10~11%, compared to the concentration without chemical addition. When coagulant was added into mixed liquor, chemical (aluminium sulfate) cost was estimated to be 4~10 times higher than in secondary effluent coagulation/separation process. Sludge production to be wasted was also 4~10 times higher than secondary effluent coagulation/separation process.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.950-955
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• 2007

Non-point source control system which had been designed only for oil-water separation in the fields of oil refinery and garage was upgraded in this research for the removal of runoff pollutants in impervious urban area. Pollutants including oil from driveway and bridge were eliminated by two types of pathway in the system. One is the coalescence mechanism that the oil droplets in the runoff come into contact with each other in the spiral buoyant media surface and form larger coalesced droplets of oil that are carried upstream to the oil layer. The other is the precipitation that solids in runoff were settled by gravity in the system. In this research, coalescing characteristics of oil and water separation were investigated through image analyses, and efficiencies of the non-point source control system were evaluated using dust in driveway and waste engine oil. Media made of high density and high molecular weight polyethylene was indeterminate helical shape and had sleek surface by analysing SEM photographs and BET. Surface area and specific gravity of media which were measured directly were 1,428 $mm^2$ and 45.3 $kg/m^3$ respectively. From the image analyses of the oil droplets photographs which were taken by using microscope, it was proved clearly that the coalescence was the main pathway in the removal of oil from the runoff. Finally, the performances of the non-point source control system filled up with the media were suspended solid $86.6\sim95.2%$, $COD_{Cr}$, $87.3\sim95.4%$, n-Hexane extractable materials $71.8\sim94.8%$ respectively.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.166-170
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• 2013

BACKGROUND: Persimmon growers have often tried various regimens of K fertilization to improve fruit quality. This experiment was conducted to determine the effects of K rates on concentration of inorganic elements in different tree organs and on fruit characteristics. METHODS AND RESULTS: Six-year-old non-astringent 'Fuyu' persimmons, grown in 50-L pots, were used. Total K amounts of 0 (no-application), 12, 25, 37, and 66 g were fertigated to a pot with KCl solution at 3-to 4-day intervals from July to September. The 0 K trees received no K fertilizer for the two previous years. Leaves, fruits, and shoots were sampled in November. K concentrations in leaves and shoots increased significantly by increasing K rate; leaf K, 0.49% for the 0 K, increased to 3.09% for the 37 g and 3.11% for the 66 g trees. Fruit K was notably lower for the 0 K, but there were no significant differences among the trees as long as they were supplied with more than 12-g K. In the trees with 0 K, leaf necrosis in the margin was apparent in June and the symptom progressed toward the midrib. Some leaves scorch-rolled from the margin in August. The greatest effect of K rates was on fruit size; it significantly increased to 181 g for the 12 g, 203 g for the 37 g, and 206 g for the 66 g compared with 150 g for the 0 K trees. However, K rates did not affect firmness and soluble solids of the fruits. The fruits of the 0 K trees were characterized by better coloration. CONCLUSION(S): The K-rate effect on inorganic elements depended on tree organs and fruit size was the major parameter to be affected by the K rates.

• Journal of Environmental Impact Assessment
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• v.26 no.1
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• pp.27-43
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• 2017

The objectives of the study were to evaluate fish compositions, endangered species, community structure, physical habitat, and general water quality for a preliminary environmental impact assessment of Jeokbyeok River on the road construction between two regions. Total number of species and total number of individuals, based on CPUE, were 23 and 1186, respectively. The endangered species (I, II) as the legal protection species were Pseudopungtungia nigra (79 samples) Gobiobotia brevibarba) (5) Gobiobotia macrocephala (2), indicating a requiring of endangered species conservation. In the meantime, exotic species and ecological disturbing species such as Micropterus salmoides and Lepomis macrochirus, were not present, indicating a well conserved area. According to fish community analysis, values of species diversity index were high (range: 0.788 - 1.030), and the dominance index were low (range: 0.097 - 0.183), indicating that the fish community in this area was maintained well without high dominacne by specific species. Also, fish analysis on tolerance guilds and trophic guilds showed that the proportions of sensitive species were largely exceeded the proportions of the tolerant species, while the proportions of insectivore species were largely exceeded the proportions of the omnivore species. This outcome suggests that the ecosystem was well maintained in terms of tolerance and trophic compositions (food chain). Ecological health, based on the multi-metric fish model of Fish Assessment Integrity (FAI), reflected those fish conditions. In other words, values of FAI model averaged 82.4, which means a "good condition" in the criteria of ecological health by the Minstry of Environment, Korea. In addition, general water quality and physical habitat analyses showed that the system was in good condition. Under these conditions, if the road constructions between the two regions happen in the future, inorganic suspended solids may increase in the waterbody, and this may result in indirect or direct influences on the physical habitats and food chain as well as fish compositions, so the ecological protections and prevention strategy from the soil erosion are required in the system.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.215-223
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• 1978

In Korea, the annual production of watermelon and cantaloupe melon is around 110,000 to 170,000 Metric Tons, and as the fruit does not keep well, studies were conducted to determine the feasibility of preservation in the form of natural juice or lactic fermented juice. The results obtained in these studies are summarized as follows: (1) The average yield of juice obtained from watermelon was 56.2%, and from cantaloupe melon 65.8%, of the fresh weight. (2) The colloidal components of watermelon juice separated from the juice by sedimentation within 24 hours. Cantaloupe melon juice gave a stable colloidal dispersion. (3) No change in the colour of the juices was detected by sensory evaluation or instrumental methods after they were treated at $100^{\circ}C$ for 5 minutes. (4) The addition of canesugar to give a total solids content of 11/13 Brix gave juices which were preferred by most tasters. (5) Lactic fermentation of natural juices pasteurised at $90^{\circ}C$ for 5 minutes, and inoculated with a pure culture of lactic acid bacteria proceeded without interference from competing microorganisms. (6) Sensory evaluation of lactic fermented juices indicated that 60% of tasters found the juices as acceptable or better than commercial fruit nectars at present on the market. (7) Taste panels showed a preference for natural melon juices over the lactic fermented juices. (8) The peroxidase activity of cantaloupe melon juice was higher than that of watermelon juice, with juice extracted from the core of the fruit showing a higher activity than that from other portions of the tissue. (9) Two types of peroxidase, of differing heat stability were detected in both juices. The more heat stable peroxidase had a decimal reduction time of 40 minutes at $80^{\circ}C$ and a z value of $11^{\circ}C$.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.645-650
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• 2011

Pear cultivar 'Supergold' (Pyrus pyrifolia var. culta Nakai) was originated from the cross between 'Chuwhangbae' and 'Manpungbae' with the aims of improving the fruit quality of 'Chuwhangbae' cultivar at Pear Research Station of National Institute of Horticultural & Herbal Science, Rural Development Administration in 1994. 'Supergold' was preliminarily selected in 2002 and named in 2008. The tree shows a vigorous growth habit and semi-spread characters like as 'Manpungbae'. Furthermore, it has sufficient flowers and carries abundant pollen grains, so it can also be used as a pollinator. 'Supergold' is highly resistant to black leaf spot (Alternaria kikuchiana) in the field condition. The optimum harvest time is around Sep. 11th, which is ahead of 'Whangkeumbae' about 5 days in the harvest period. The fruit shape is oblate and fruit skin color is greenish-white at harvesting time. The average weight of fruit is 570 g, and the soluble solids content is $13.6\;^{\circ}Brix$. The flesh is very soft and juicy, and renders good eating quality. Shelf life is about 6 months under the cold storage condition. To determine the self-incompatibility (SI) genotype of 'Supergold' pear cultivar, it was crossed with other cultivars of which SI genotypes have already known. The result of cross-pollinations of 'Supergold' with other cultivars showed relatively high rates of fruit set from 64.5% to 91.0%, except for the cross with pollens of 'Nijisseiki' that represented only 28.8% of fruiting rate. Although sometimes the stigma of 'Supergold' crossed with 'Hayatama', 'Chojuro', and 'Nijisseiki' showed malformed pollen tube tips, 'Supergold' is generally supposed to have cross-compatibility with all other pollen donor cultivars. It is considered that the S-allele of 'Supergold' is $S_3S_4$, which is based on the result of PCR-RFLP.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.202-209
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• 2014

This study was conducted to investigate the effects of low temperature shipping condition and precooling treatments (forced air and room cooling) on everbearing strawberry through export simulation of 'Goha' and 'Flamenco' cultivars. After harvest, it took two days to prepare export procedure such as precooling, sorting, storage, transportation, quarantine and handling, and then everbearing strawberry was carried out shipping at room ($20-25^{\circ}C$) or low ($8^{\circ}C$) temperature conditions. In the case of shipping at room temperature, weight losses of both cultivars were increased up to 10% after 2 days where 'Goha' being 2% higher than that of ' Flamenco'. In 'Flamenco' cultivar, shipping temperature and precooling treatment were not effective in firmness and soluble solids contents during transporting periods. However, in 'Goha' cultivar, room cooling treatment and low shipping temperature were effective in maintaining firmness until 4 days after shipping. Especially titratable acidity was affected by shipping temperature ($P{\leq}0.001$) and precooling treatments ($P{\leq}0.05$) in 'Goha' cultivar. Also shipping temperature under $8^{\circ}C$ delayed coloring and decay incidence of both strawberry cultivars, and precooling treatments of both forced air and room cooling reduced frequency of decay. The shelf life of everbearing strawberry at low shipping temperature was extended more than 4 days compared with shipping at room temperature. Precooling treatment including forced air or room cooling will be useful for the two cultivars when they are transported at low temperature. In 'Flamenco' cultivar, the effect of forced air and room cooling was similar, whereas in 'Goha' room cooling was more effective.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.85-102
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• 1993

This study was conducted to achieve develop organic sludge recycling technology as sludge make a prey of earthworm. Therefore sludge treatment and recycling technology is an important field by which this research project to solve landfill site and reduction treatment expense using vermicomposting treatment process on the waste sludge from the biological wastewater treatment plant. In experimental results on the optimum conditions of vermicomposting of nightsoil treatment sludge, survival rates were observed 98.3% in temperature of $10-15^{\circ}C$, 75% in pH 5.8-7.5 and 100% in density of $1/79.8cm^3$, respectively. Liveweight changes of earthworm were increased 266% in temperature of $10-15^{\circ}C$, 227% in pH 5.8-7.5 and 325 % in density $1\;cap./79.8cm^3$, respectively. Casting production rate were generated 0.06 g/cap./day in temperature $20-25^{\circ}C$, 0.065 g/cap./day in pH 5.8-7.5 and 0.1 g/cap./day in density $1\;cap./79.8cm^3$, respectively. Cocoon production numbers were observed 3.8 ea. /cap.in $10-15^{\circ}C$, 2.95 ea./cap.in pH 5.8-7.5 and 3.16 ea./cap. in $1\;cap./79.8cm^3$ during 6 weeks, respectively. pH was droped by 6.2 to 5.7, volatile solids was decreased by 2.9%, $NH_3-N$ were also reduced by $6.984{\mu}g/g$ to $0.991{\mu}g/g$. $NO_3-N$, however, were increased by $3.213{\mu}g/g$ to $7.706{\mu}g/g$. Fecal coliforms and pathogenic bacteria are analyzed by microbiological method to assess public health safety of casting. Number of fecal coliform groups were reduced 88.6-99.1% (Avg. 95.7%) approximately. And pathogenic bacteria such as Salmonella, Shiegella and Vibrio, were not isolated from the earthworm cast.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.75-86
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• 2003

In the near future, the capacity of conventional anaerobic digester is thought to be insufficient because of the increase of the total solids from expansion of intercepting sewer, sewage quantity and direct input of night soil from near apartment districts. The objectives of this study was to investigate the improvement of digestion efficiency using microbial agent(Bio-dh). The system was a pilot-scale, two-staged, anaerobic sludge digestion system. The first-stage digester was heated and mixed. The agitation velocity of the first-stage digester was 120rpm. The second-stage digester was neither heated nor mixed. The Digestion temperature was kept at $35{\pm}1^{\circ}C$ The detention time of digester was 19 days. The dosage of sewage sludge and microbial agent were $0.65m^3/day$ and $0.5{\ell}/day$, respectively. The experiments was run for 25days. Three times a week, $COD_{Mn}$ and SS of effluent, TS, VS, and biogas production rate were measured. Temperature, pH, and alkalinity were measured daily. The results were as follows ; Without microbial agent, digestion efficiencies ranged 46.0%~50.9%(mean=48.6%), with microbial agent(Bio-dh), digestion efficiencies ranged 52.8%~57.3%(mean=54.2%). Consequently, microbial agent(Bio-dh) increased the sludge digestion efficiency about 12%. Also, Without microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 1,639mg/L, 4,888mg/L respectively. With microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 859mg/L, 2,405mg/L respectively. Consequently, microbial agent(Bio-dh) increased the removal efficiency of $COD_{Mn}$ and SS about 47.6% and 50.8%, respectively.