• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.83-89
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• 2000

Bentonite has been considered as a liner material to restrict the release of hazardous heavy metals from the landfill. The adsorption of copper onto a domestic bentonite was studied to provide the adsorption isotherm and the effect of solution chemistry and temperature. The copper adsorption was fitted well to a Freundlich isotherm, in which Freundlich constants and correlation coefficient were calculated to be $K_F=1.18$, n=1.65, and $r^2=0.97$, respectively. The distribution coefficients ($K_d$) for the adsorption of copper decreased with increasing initial copper concentration. The $K_d$ increased with increasing the pH of solution, and drastically increased at pH > 5.3 because of precipitation of most copper species. As the ion strength of $Na^+$ in solution increased the $K_d$ decreased, while it increased with increasing the concentration of $SO_4{^{2-}}$ in solution. An increase in the temperature of experimental solution decreased the $K_d$ values.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.318-326
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• 2014

This study was conducted to investigate the potential of non-used forest biomass residues as raw materials for making wood pellets with additives such as wood tar and starch and to evaluate fuel characteristics of the pellets. Wood tar, a by-product provided from the carbonization process of wood, could be a suitable additive for wood pellet production due to its higher calorific value and lower hazardous heavy metals, such as cadmium and mercury, compared to woody biomass. When the wood tar (10 wt%) was added, the calorific value was increased from 4,630 kcal/kg (wood pellet without additive) to 4,800 kcal/kg (wood pellet with additive). With the increase of additive amount into wood pellet, the length and individual density of wood pellet increased. In addition, bulk density of the pellets was increased, whereas the fine content was decreased. Consequently the overall productivity of wood pellets was improved by adding 2 w% additives into wood pellets; the percentage of productivity increase was 5.9% and 4.9% for adding starch and wood tar, respectively.

• Journal of Environmental Impact Assessment
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• v.30 no.6
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• pp.413-424
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• 2021

Health impact assessment in the environmental impact assessment is conducted to determine whether to exceed the standard of each single substance and to establish appropriate reduction measures. In some development projects, although all substances in risk assessment meet the standard, exposure concentration is very close to it. However, considering the cumulative exposure of all substances, health effects are likely to occur considerably severer than those of individual substances, so it is necessary to prepare a concrete and improved methodology for integrating evaluation of emissions to identify the health effects actually exposed to receptors of living things. This study established the definition of cumulative risk assessment through overseas advanced cases and domestic and foreign literature reviews, and proposed a methodology for utilizing cumulative risk assessment considering health effects on multiple substances when developing industrial complexes. Applied by the proposed methodology, integrated indicators forfourtypes of hazardous heavy metals (Ni, Cr⁶⁺, Cd, As) emitted from industrial complexes were calculated, and applicability was tested with case of the industrial complex development projects conducted over the last decade (2011-2020).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.451-457
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• 2019

In this study, the characteristics of coffee grounds were reviewed by making them from solid fuel through heat-drying and oil-drying method. The differences in the higher calorific power by each dried sample were compared. And industrial analysis using the thermogravimetric analyzer was considered for applicability to organic waste and oily samples. Before and after drying, the surface of the specimen was observed with SEM equipment and the ingredients were measured through the EDS equipment. As a result, no other hazardous substances, such as heavy metals, were measured. Next, The differences between thermal decomposition and combustion reactions were considered through the TG and DTG curves. As a result, it is that the oil-dried coffee grounds is longer to burn than the heat-dried coffee grounds. Finally, the combustion gases emitted through the thermogravimetric analyzer were collected and the carbon monoxide and carbon dioxide performed qualitative and quantitative analysis using GC over time.

• Journal of Life Science
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• v.32 no.12
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• pp.997-1004
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• 2022

To verify the nutritional superiority and safety of Protaetia brevitarsis larvae fed a food source containing soybean curd cake, the nutrients and harmful substances of larvae reared only with fermented oak sawdust and a food source containing soybean curd cake were comparatively analyzed. The crude protein content was 50.0% in the larvae fed with a food source containing soybean curd cake (SCC), which was 1.1 times higher than that of the larvae fed with fermented oak sawdust (FOS) at 44.7%. Potassium, which showed the highest content among macrominerals, was 2.5 times higher in SCC (3,169.6 mg/100 g) than in FOS (1,245.9 mg/100 g). Among trace minerals, zinc showed 12.6 times higher content than FOS (8.2 mg/100 g) in SCC (103.0 mg/100 g). As a result of the analysis of harmful substances, all heavy metals met the edible insect control standards, and pathogenic microorganisms, such as E. coli and Salmonella spp, were not detected. According to the above study, the larvae of P. brevitarsis fed soybean curd cake contain various nutrients, and safety has also been confirmed, so it is judged to be suitable for use as food.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.238-244
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• 2009

This survey was conducted as a surveillance program following the establishment of safety guidelines for agricultural products in Korea. Concentrations of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) were measured in 421 samples using a mercury analyzer or ICP-MS. The average levels of Pb in mg/kg were 0.021 for rice, 0.020 for corn, 0.028 for soybeans, 0.034 for red beans, 0.025 for sweet potatoes, 0.021 for potatoes, 0.019 for Chinese cabbage, 0.031 for spinach, 0.021 for Welsh onions, and 0.011 for radishes. The average levels of Cd in mg/kg were 0.021 for rice, 0.002 for corn, 0.020 for soybeans, 0.006 for red beans, 0.008 for sweet potatoes, 0.011 for potatoes, 0.007 for Chinese cabbage, 0.035 for spinach, 0.006 for Welsh onions, and, 0.006 for radishes. The average levels of As in mg/kg were 0.103 for rice, 0.005 for corn, 0.007 for soybeans, 0.005 for red beans, 0.005 for sweet potatoes, 0.004 for potatoes, 0.007 for Chinese cabbage, 0.015 for spinach, 0.009 for Welsh onions and, 0.006 for radishes. Finally, the average levels of Hg in ${\mu}g/kg$ were 2.3 for rice, 0.2 for corn, 0.6 for soybeans, 1.4 for red beans, 0.1 for sweet potatoes, 0.3 for potatoes, 0.5 Chinese cabbage, 2.1 for spinach, 0.5 for Welsh onions, and 0.2 for radishes. Based on the Korean public nutrition report 2005, these levels (or amounts) are calculated only at 2.6% for Pb, 8.7% for Cd, 1.2% for Hg of those presented in provisional tolerable weekly intake (PTWI) which has been established by FAO/WHO. Therefore, the levels presented here are presumed to be adequately safe.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.329-336
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• 2006

Iron manufacturing process involves production of various by-product including slag, sludge, sintering and EAF(Electric Arc furnace dust). Some of the by-products such as EAF and sintering dust are disposed of as waste due to their high heavy metal contents. It has been notice for many years that the EAF dust also contain about 65% of Fe(0) and Fe(II) and then the possible utilization of the iron. One possibility is to apply the EAF as a lining material in conjunction with clay or HDPE liners, in waste landfill. The probable reaction between the leachate containing toxic elements such as TCE, PCE dioxine and $Cr^{6+}$ is reduction of the toxic materials in corresponding to the oxidation of the reduced iron and therefore diminishing the toxicity of the leachate. It is, however, prerequisite to evaluate the leaching characteristics of the EAF dust before application. Amelioration of the leachate would be archived only when the level of toxic elements in the treated leachate is less than that of in the untreated leachate. Several leaching techniques were selected to cover different conditions and variable environments including time, pH and contact method. The testing methods include availability test, pH-stat test and continuous column test. Cr and Zn are potentially leachable elements among the trace metals. The pH of the EAF dust is highly alkaline, recording around 12 and Zn is unlikely to be leached under the condition. On the contrary Cr is more leachable under alkaline environment. However, the released Cr should be reduced to $Cr^{3+}$ and then removed as $Cr(OH)_3$. Removal of the Cr is observed in the column test and further study on the specific reaction of Cr and EAF dust is underway.