• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.771-780
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• 2014

In this study, the various organic supports (i.e., silicone, acrylonitrile-butadiene-styrene, epoxy, and, butadiene rubber) with great sorption capacity of organic contaminants were chosen to develop nano-ZnO/organic composites (NZOCs) and to prevent the detachment of nano-ZnO particles. The water resistance of the developed NZOCs were evaluated, and the feasibility of the developed NZOCs were investigated by evaluating the removal efficiency of 1,1,2-trichloroethylene (TCE) in the aqueous phase. Based on the results from water-resistance experiments, long-term water treatment usage of all NZOCs was found to be feasible. According to the FE-SEM, EDX, and imaging analysis, nano-ZnO/butadiene rubber composite (NZBC) with various sizes and types of porosity and crack was measured to be coated with relatively homogeneously-distributed nano-ZnO particles whereas nano-ZnO/silicone composite (NZSC), nano-ZnO/ABS composite (NZAC), and nano-ZnO/epoxy composite (NZEC) with poorly-developed porosity and crack were measured to be coated with relatively heterogeneously-distributed nano-ZnO particles. The sorption capacity of NZBC was close to 60% relative to the initial concentration, and this result was mainly attributed to the amorphous structure of NZBC, hence the hydrophobic partitioning of TCE to the amorphous structure of NZBC intensively occurred. The removal efficiency of TCE in aqueous phase using NZBC was close to 99% relative to the initial concentration, and the removal efficiency of TCE was improved as the amount of NZBC increased. These results stemmed from the synergistic mechanisms with great sorption capability of butadiene rubber and superior photocatalytic activities of nano-ZnO. Finally, the removal efficiency of TCE in aqueous phase using NZBC was well represented by linear model ($R^2{\geq}0.936$), and the $K_{app}$ values of NZBC were from 2.64 to 3.85 times greater than those of $K_{photolysis}$, indicating that butadiene rubber was found to be the suitable organic supporting materials with enhanced sorption capacity and without inhibition of photocatalytic activities of nano-ZnO.

• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.16-34
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• 2015

Impervious covers(IC) are artificial structures, such as driveways, sidewalks, building's roofs, and parking lots, through which water cannot infiltrate into the soil. IC is an environmental concern because the pavement materials seal the soil surface, decreasing rainwater infiltration and natural groundwater recharge, and consequently disturb the hydrological cycle in a watershed. Increase of IC in a watershed can cause more frequent flooding, higher flood peaks, groundwater drawdown, dry river, and decline of water quality and ecosystem health. There has been an increased public interest in the institutional adoption of LID(Low Impact Development) and GI(Green Infrastructure) techniques to address the adverse impact of IC. The objectives of this study were to construct the modeling site for a samll urban watershed with the Storm Water Management Model(SWMM), and to evaluate the effect of various LID techniques on the control of rainfall runoff processes and non-point pollutant load. The model was calibrated and validated using the field data collected during two flood events on July 17 and August 11, 2009, respectively, and applied to a complex area, where is consist of apartments, school, roads, park, etc. The LID techniques applied to the impervious area were decentralized rainwater management measures such as pervious cover and green roof. The results showed that the increase of perviousness land cover through LID applications decreases the runoff volume and pollutants loading during flood events. In particular, applications of pervious pavement for parking lots and sidewalk, green roof, and their combinations reduced the total volume of runoff by 15~61 % and non-point pollutant loads by TSS 22~72 %, BOD 23~71 %, COD 22~71 %, TN 15~79 %, TP 9~64 % in the study site.

• Korean Journal of Environmental Agriculture
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• v.28 no.2
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• pp.171-178
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• 2009

Water shortages are expected to be a major impact of climate change. This study examined the growth of Chinese cabbage seedling using reclaimed wastewater and waste nutrient solution as alternative irrigation resources. Generally, the concentration of nutrients, such as $K^+$, $NH_4^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$,$NO_3^-$, $PO_4^-$ and $SO_4^{2-}$, in waste nutrient solution was higher than that in wastewater. However, Chinese cabbage seedling irrigated with wastewater was supplied a higher concentration of $Na^+$ and $Cl^-$ than waste nutrient solution. The growth of Chinese cabbage seedling irrigated with waste nutrient solution was similar or higher than those irrigated with groundwater as control, while the growth of those irrigated with wastewater was similar to those irrigated with groundwater. The total nitrogen uptake in Chinese cabbage seedling irrigated with groundwater, waste nutrient solution from organic and inorganic hydroponic cultures, and wastewater was 5.47, 10.02, 5.20, and 4.59 mg/plant, respectively. The nitrogen uptake of Chinese cabbage seedling irrigated with waste nutrient solution from organic hydroponic substrates in a 50% lower dose than recommended was 8.34 mg/plant, which is higher than that of the cabbage irrigated with groundwater. Overall, the results suggest that waste nutrient solution and wastewater can be used as alternate water resources, and can allow a reduction in the amount of fertilizer needed to raise Chinese cabbage seedling.