• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.1-6
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• 2016

In this year, Koreans have a shortage in agricultural and drinking water due to severe algal blooms generated in major lakes. Waste oyster shells were obtained from temporary storage near the workplace at which oysters were separated from their shells. Heating ($1000^{\circ}C$ for 1 h in air) was employed to convert raw oyster shell powders into calcium oxide powders that reacted efficiently with phosphorus and nitrogen to remove algal blooms from eutrophicated wastewater. As the dispersed amount of heated oyster shell powders was increased, water clarity and visual light penetration were improved. Coagulation, precipitation and carbonation process of the heated oyster shell powders in a water purifier facilitated removal of eutrophication nutrient such as phosphorus and nitrogen, which is both beneficial and economically viable. $CO_2$ implantation by carbonation treatment not only produced thermodynamically stable CaO in oyster shells to derive precipitated calcium carbonate (PCC) but also accelerated algal removal by activation of coagulation and precipitation process. The use of oyster shell powders led to a mean reduction of 97% in total phosphate (T-P), a mean reduction of 91% in total nitrogen (T-N) and a maximum reduction of 51% in chemical oxygen demand (COD), compared with the total pollutant load of raw algal solution. Remarkable water quality improvement of algal removal by heated oyster shell powders and PCC carbonation treatment will allow utilization as water resources to agricultural or industrial use.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.3
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• pp.93-102
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• 1989

With an objective to provide basic information for the management and the prediction of eutrophication in lentic water Systems, total amount of Kjeldahl nitrogen(T-N) and phosphorous(T-P) from irrigated water and drained water from flooded paddies were investigated during the rice growing period of 1988. A 29.3 ha paddies near Jungnam-myun, HwaSung-gun, Gyungi Province, Korea was instrumented for measuring runoff and sampling irrigated water and drained water from paddies. The following conclusions may be drawn from the result of this study. 1.During 115 days of investigation, T-N load for paddies was 362.6kg and T-P 63.44kg.These would be converted to 12.4kg T-N/ha and 2.17kg T-P/ha, respectively. 2.The T-N and T-P loadings in different periods showed a significant difference. The 25% of T-N loading was drained soon after fertilization period and 60% was drained during the rainy season from July 5 to July 24. 3.Annual loadings from paddies could be calculated to 30kg T-N/ha/year and 52kg T-P/ha/year considering non-measurement periods. 4.After the rainy season, the nutrient loads from drained water showed much less than those from irrigated water, and it may be suggested that the paddies would act as a stabilization pond. 5.The average concentrations of nutrients at 0.9km downstream from investigated paddies were 2.02(T-N) mg/l and 0.52(T-P) mg/I, which were 1.82(T-N) mg/l and 0.056(T-P)mg/l lower than those of drained water from paddies.

• Journal of Species Research
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• v.2 no.2
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• pp.159-166
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• 2013

Typical of large, oligotrophic lakes, Lake H$\ddot{o}$vsg$\ddot{o}$l, Mongolia, exhibits complex morphometry which should support a spatially heterogeneous community of benthic macroinvertrates. The lake also exhibits a broad range of land uses. Based on the variation in land use and complex physical habitat of the lake (e.g. substrate variation and presence of affluent streams in bays), we asked two questions. First, does density of total benthic macroinvertebrates vary between different bays in Lake H$\ddot{o}$vsg$\ddot{o}$l? Second, does density of individual benthic taxa vary by bay? Samples collected in 1997, the last year for benthic sampling of the lake, were designed to test for variation in macroinvertebrate density between bays and can now be used to establish baseline variation in density for future studies. A total of 56 Ponar grab samples were analyzed from six bays in Lake H$\ddot{o}$vsg$\ddot{o}$l. Results of a general linear model analysis of variance showed that total density of macroinvertebrates varied only slightly between bays of the lake, but that most individual taxa showed significant variation between bays. Variation in density for most taxa was linked to substrate composition rather than other geographic or physical variables in the lake. Recent increases in grazing intensity and ecotourism along the shores should be managed to reduce the nutrient load into the lake to avoid impairment of the benthic biota of this unique, ancient ecosystem.

• Journal of Environmental Science International
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• v.24 no.10
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• pp.1253-1264
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• 2015

This study assessed the fertilizing value of struvite deposit recovered from swine wastewater in cultivating Chinese cabbage. Struvite deposit was compared with commercial fertilizers: complex, organic and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test obviously presented that the struvite deposit more facilitated the growth of Chinese cabbage than organic and compost fertilizers even though complex fertilizer was the most effective in growing Chinese cabbage. It was revealed that the growth rate of Chinese cabbage was simultaneously controlled by phosphorus (P) and potassium (K). Also, the nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Specifically, P was the most abundant component in the vegetable tissue of struvite pot. Meanwhile, the utilization of struvite as a fertilizer led to the lower accumulation of chromium ($Cr^{6+}$) than other pots, except for compost fertilizer pots, and no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the Chinese cabbage. The experimental results proved that the optimum struvite dosage for the cultivation of Chinese cabbage was 2.0 g struvite/kg soil. On the basis of these findings, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for Chinese cabbage cultivation.

• Environmental Engineering Research
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• v.21 no.1
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• pp.29-35
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• 2016

This study evaluated the fertilizing value of struvite deposit recovered from swine wastewater in cultivating lettuce. Struvite deposit was compared to complex fertilizer, organic fertilizer and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test showed that the struvite deposit better enhanced lettuce growth in comparison to commercial fertilizers. It was revealed that the growth rate of lettuce was simultaneously controlled by phosphorus (P) and magnesium (Mg). Moreover, nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Meanwhile, struvite application led to the lower accumulation of mercury (Hg), lead (Pb), chromium ($Cr^{6+}$) and nickel (Ni). In addition, no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the lettuce tissue was observed in struvite application pots. The experimental results proved that the optimum struvite dosage for lettuce cultivation was 0.5 g struvite/kg soil. The column experiments clearly showed that ammonia nitrogen was more slowly released from struvite deposit than from complex fertilizer. Consequently, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for lettuce cultivation.

• Journal of Nutrition and Health
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• v.41 no.7
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• pp.645-657
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• 2008

This study was conducted to study the relationship between food intakes, glycemic index (GI), glycemic load (GL), and body weight with high school boys residing in Seoul. The subjects of 329 boys were divided into normal weight group (BMI < $23\;kg/m^2$, n = 212) and overweight group (BMI ${\geq}\;23\;kg/m^2$, n = 117) by body mass index (BMI). The food intakes data obtained by the 3-day food record were analyzed by Can pro 3.0 software. Anthropometric measurements and physical activities were collected from each subject. Daily dietary glycemic index (DGI) and dietary glycemic load (DGL) were calculated from the 3-day food record. Body weights and BMI of normal weight group were 58.8 kg and $19.9\;kg/m^2$ and those of overweight group were 79.2 kg and $26.8\;kg/m^2$, which were significantly different between two groups (p < 0.05). Total food and animal food intakes of normal weight group were significantly higher than overweight group (p < 0.05), and vegetable food and other food intakes of normal weight group showed higher than overweight group. All nutrient intakes of normal weight group were higher than overweight group. Dietary fiber, calcium, potassium and folate intakes of normal weight group and overweight group were under 65% of the dietary reference intakes (DRIs). Major food sources of energy intake for both groups were rice, pork and instant noodle in order. Mean adequacy ratio (MAR), an index of overall dietary quality were 0.83 in normal weight group and 0.79 in overweight group, which showed significantly higher in normal weight group than overweight group (p < 0.05). Mean daily dietary GI of normal weight group and overweight group were 67.7 and 68.2, respectively. Mean daily dietary GL of normal weight group and overweight group were 214.6 and 202.7, respectively, and which was significantly different between the two groups (p < 0.05). Major food sources contributed to DGI and DGL were rice ($\geq$ 55%) in both groups. DGI and DGL were not significantly correlated with anthropometric data. Activity adjusted to energy intake was negatively correlated with percentage of body fat (r = -0.1308, p < 0.01) and that was positively correlated with height (r = 0.1227, p < 0.05) and lean body mass (r = 0.1351, p < 0.05).

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.611-619
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• 1998

This study was carried out to examine the effects of soil acidification on growth and nutrient status of 2 - year - old Pious densiflora Sieb. et Zucc. seedlings grown for 120 days in brown forest soils acidified with $H_2SO_4$ solution with or without leaching rations from the soil. The concentrations of A1 in the acidified soils increased with increasing amount of $H^+$ added to the soil. The total dry weight of the seedlings was decreased by the addition of the $H_2SO_4$ solution. The increase of Al concentration in the belowground part resulted from the decreased concentration of essential mineral elements such as Ca and Mg in the aboveground part. In addition, a strong positive correlation(r=0.96, p<0.001) was observed between the dry weight of the seedlings and the molar (Ca+Mg+K)/A1 ratio of the soil solution. When the molar (Ca+Mg+K)/Al ratio was approximately 7.0, the dry weight of the seedlings began to decrease compared with that of the seedlings in the control treatment. The seedlings with the molar (Ca+Mg+K)/Al ratio of 1.0 resulted from approximately 40% growth reduction compared with the control value. The results suggest that the molar (Ca+Mg+K)/Al ratio of the soil solution may be a useful indicator for assessing the critical load of acid deposition.

• Journal of the Korean GEO-environmental Society
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• v.15 no.4
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• pp.29-36
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• 2014

The purpose of this study investigates the delivery characteristics according to the load of pollutants by calculating the delivery rate of targeted areas on pollutants in Sapkyo reservoir. The main rivers of Sapkyo reservoir are Namwoncheon, Dogocheon, Sapkyocheon, Muhancheon and Gokgyocheon. The delivery rate and their characteristics of five major rivers during rainfall season are investigated. As th result, biochemical oxygen demand (BOD), total nitrogen (T-N) and total phosphorous (T-P) of total delivery rate are calculated by 0.40, 0.34 and 0.08, respectively. The delivery rate of T-P compares to other water quality is investigated relatively low. Looked at the overall characteristics of the watershed, the delivery rate of T-N and T-P is little change in the rate of the year, too. The delivery rate of T-N is calculated from 0.2 to 0.3 in the dry season, and from 0.31 to 0.39 in a flood, respectively. The delivery rate of T-P is calculated to more than 0.3 in the dry season, and 0.11 in a flood. It is similar values which the average annual delivery rate of T-P is 0.08. Therefore, the measured delivery rate of Sapkyo reservoir can be applicable such as a delivery rate of similar features of the terrain and land use.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.266-273
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• 2008

The effects of soil acidification on the seedling growth and nutrition of Pinus densiflora and Quercus acutissima were investigated. The relationship between the seedling growth and molar (Ca+Mg+K)/Al ratio of in soil solution was examined. The results suggested that growth inhibition of seedling Pinus densiflora and Quercus acutissima was due to the low pH of soil solution, which was followed by leach of Al into soil solution, and decrease of essential elements, such as Ca in aerial pant of the seeding caused by the increase of Al concentration in subterranean pant of the seedlings. The level of growth inhibition was determined not only by Al concentration, but also by the balance of inorganic elements, Al, Ca, Mg and K. The growths of two species in total dry weight were clearly inhibited when molar (Ca+Mg+K)/Al ratio of the soil was lower than 6.0. The growth in dry weight, in the condition of the molar ratio was 0.8, was decreased 60% or 50% for the seedling of Pinus densiflora or Quercus acutissima respectively. It was concluded that the molar (Ca+Mg+K)/ Al ratio could be an important index for evaluation of the effects of soil acidification, due to acid deposition such as acid rain, on growth of trees and nutrition. And it might be a more useful indicator for evaluation of critical load of acid deposition on forest ecosystems.

• 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.