• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.191-198
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• 2014

A semi-pilot hybrid system composed of a photocatalytic reactor and a biofilter was operated under various operating conditions in order to treat malodorous waste air containing both hydrogen sulfide and ammonia which are major air pollutants emitted from composting factories and many publicly owned treatment works (POTW). When both hydrogen sulfide and ammonia contained in malodorous waste air were treated simultaneously by a biofilter system, its performance of ammonia removal was much more poor than that by a biofilter system treating waste air containing only ammonia, unlike its performance of hydrogen sulfide removal. For semi-pilot hybrid system, the removal efficiencies of hydrogen sulfide and ammonia turned out to be ca. 83 and 65%, respectively. Therefore, for semi-pilot hybrid system, the removal efficiencies of hydrogen sulfide and ammonia was increased by ca. 4 and 30%, respectively, compared to those of semi-pilot biofilter system (control). In addition, the maximum elimination capacities of hydrogen sulfide and ammonia for semi-pilot hybrid system turned out to be ca. 60 and $37g/m^3/h$, respectively. These maximum elimination capacities of hydrogen sulfide and ammonia were estimated to be ca. 9.1% and ca. 23.3% greater than those for semi-pilot biofilter system (control), respectively. Therefore, the semi-pilot hybrid system contributed the enhancement of removal efficiency and the maximum elimination capacity of ammonia in a higher degree than that of hydrogen sulfide, compared to the semi-pilot biofilter system.

• Fire Science and Engineering
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• v.30 no.6
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• pp.48-56
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• 2016

A crude oil leakage from a large atmospheric storage tank occurred on 4 April 2014 at 14:50 in Ulsan City, while storing the crude oil in the tank. Emergency Rescue Control Group was deployed in the scene. The company, Fire Service Headquarters and associated agencies got together in Command Post (CP) for discussing an effective corresponding strategy. Many solution plans were drafted in the debate such as power down, stopping the facilities, checking the density of inflammable gas, suppressing oil evaporation, moving the leaked crude oil to a nearby tank and a processing plant and avoiding marine pollution. All the solutions were carried out in cooperation with several agencies and partners. The oil leakage accident was successfully settled up within the process of responding, The Fire Service Headquarters and the company thought that the most important thing was the suppression of oil evaporation and the elimination of ignition source. With Fire Service Headquarters and several agencies' every effort, an explosion and a fire didn't occurred in the scene. This study suggest the improvement of the operating system in Emergency Rescue Control Group in case of petroleum leakage, explosion and fire accidents of atmospheric storage tank, different from a ordinary disaster. Assuming that petroleum leakage in atmospheric storage tank develop the explosion and fire accidents, the spreading speed of the flame and the burning time was experimented and compared with each other. Furthermore, this study concentrates on the effective field response plan prepared for the afterward explosion and fire accidents from petroleum leak in a storage tank, with the database experimented and analyzed in accordance with the angle of radiation in the foam nozzle and the pressure of pumping in a fire engine.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.327-333
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• 2019

For sustainable lunar exploration, the most required resources should be procured on site because it takes tremendous cost to transfer the resources from the Earth to the Moon. The technologies required for use of lunar resources refers to In-Situ Resource Utilization (ISRU). As the ISRU technology cannot be verified in the Earth, a lunar surface environment simulator is necessary to be prepared in advance. The Moon has no atmosphere, and the average temperature of the lunar surface reaches to $107^{\circ}C$ during the daytime and $-153^{\circ}C$ at night. The lunar surface is also covered with very fine soils with sharp particles that are electrostatically charged by solar radiation and solar wind. In this research, generation of vacuum environment with lunar soil mass in a chamber and simulation of electrostatically charged soils are taken into consideration. It was successful to make a vacuum environment of a chamber including lunar soils without soil disturbance by controlling evacuation rate of a vacuum chamber. And an experiment procedure for simulating the charged lunar soil was suggested by theoretical consideration in charging phenomena on lunar dust.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.445-471
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• 2023

Long-term safety over millennia is the top priority consideration in the construction of disposal sites. However, ensuring the mechanical stability of deep geological repositories for spent fuel, a.k.a. radwaste, disposal during construction and operation is also crucial for safe operation of the repository. Imposing restrictions or limitations on tunnel support and lining materials such as shotcrete, concrete, grouting, which might compromise the sealing performance of backfill and buffer materials which are essential elements for the long-term safety of disposal sites, presents a highly challenging task for rock engineers and tunnelling experts. In this study, as part of an extensive exploration to aid in the proper selection of disposal sites, the anticipation of constructing a deep geological repository at a depth of 500 meters in an unknown state has been carried out. Through a review of 2D and 3D numerical analyses, the study aimed to explore the range of properties that ensure stability. Preliminary findings identified the potential range of rock properties that secure the stability of central and disposal tunnels, while the stability of the vertical tunnel network was confirmed through 3D analysis, outlining fundamental rock conditions necessary for the construction of disposal sites.

• Journal of Animal Environmental Science
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• v.10 no.1
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• pp.47-58
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• 2004

This work was carried out to investigate the effects of rice hull continuously utilized and/or replenished on the composting properties and to obtain the fundamental data between an unsupported wall and a soil supported wall during the period of composting with pig slurry in winter season. There were no the temperature holding effects in soil supported wall. New compost facility design for the temperature holding effects from a soil supported wall was required. The results were as follows; 1. Composting 1㎥ of pig slurry caused to save on 0.31㎥ of bulking agent in the unsupported wall in comparison with a soil supported wall in the rice hull single addition, and 0.45㎥ in the rice hull gradual addition. 2. The pile in the rice hull single addition had a high temperature in 4 days of composting indicating $71^{\circ}C$ and had a tendency in repeating periodically between $40^{\circ}C$ and $65^{\circ}C$ till 43 days of composting. And also the temperature of the pile was maintained between $48^{\circ}C$ and $28^{\circ}C$ after 50 days of composting. The pile of a rice hull gradual addition had the lower point of the temperature high increasingly according to adding up rice hull during the 35 days of composting. 3. The pH recorded in the rice hull single addition was higher(8.35∼10.02) compared to the rice hull gradual addition(8.6∼9.8). The pile of a rice hull single addition had a tendency in abruptly decreasing pH of the unsupported wall during the period of between 0.363$\textrm m^3$ and 0.537$\textrm m^3$ as a unit of pig slurry per rice hull. EC depending upon the way in adding rice hull was changed between 1.10 mS/$\textrm {cm}^3$ and 1.87 mS/$\textrm {cm}^3$. 4. The organic matter in an unsupported wall of the hull single addition was maintained the level of 55% during the period between 0.119㎥ and 0.363㎥ as a unit of pig slurry per rice hull while in the soil supported wall between 48 and 70. Water soluble C:N ratio was maintained between 1 and 2 in the rice hull single addition, while between 1 and 3 in the rice hull gradual addition. 5. Fertilizer constituents were detected higher level in the unsupported wall than in the soil supported wall in all treatments. This was dependant upon the input of pig slurry.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.391-396
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• 2010

In this research the characteristics of ammonia removal from malodorous waste-air were investigated under various operating condition of biofiilter packed with equal volume of rubber media and compost for the efficient removal of ammonia, representative source of malodor frequently generated at compost manufacturing factory and publicly owned facilities. Then the optimum conditions were constructed to treat waste-air containing ammonia with biofilter. Biofilter was run for 30 days(experimental frequency of 2 times/day makes 60 experimental times.) with the ammonia loading from $2.18g-N/m^3/h$ to $70g-N/m^3/h$ at $30^{\circ}C$. The ammonia removal efficiency reached almost 100% for I through IV stage of run to degrade up to the ammonia loading of $17g-N/m^3/h$. However the removal efficiency dropped to 80% when ammonia loading increased to $35g-N/m^3/h$, which makes the elimination capacity of ammonia $28g-N/m^3/h$ for V stage of run. However, the removal efficiency remained 80% and the maximum elimination capacity reached $55g-N/m^3/h$ when ammonia loading was doubled $70g-N/m^3/h$ for VI stage of run. Thus the maximum elimination capacity exceeded $1,200g-N/m^3/day$(i.e., $50g-N/m^3/h$) of the experiment of biofilter packed with rock wool inoculated with night soil sludge by Kim et al.. However, the critical loading did not exceed $810g-N/m^3/day$ (i.e., $33.75g-N/m^3/h$) of the biofilter experiment by Kim et al.. The reason to exceed the maximum elimination capacity of Kim et al. may be attributed to that the rubber media used as biofilter packing material provide the better environment for the fixation of nitrifying and denitrification bacteria to its surface coated with coconut based-activated carbon powder and well-developed inner-pores, respectively.