• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.539-543
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• 2008

이 연구에서는 보령화력발전소 방수로 수중방류구조에 대한 수리모형실험을 수행하여 수중방류구조 내 흐름 양상을 고찰하고, 수평 유공판의 거품저감 효과를 검토하였다. 수중방류구조 내 유속은 설계시 거품의 부상 및 외해 유출 방지를 위해 고려한 목표값 1 m/s 이내에 분포하였다. 또한, 2차 낙하 위치에 수평 유공판을 설치함에 따라 거품 발생량이 크게 감소함을 확인하였다. 그러나, 수평 유공판 설치에 따라서 평균유속은 거의 변화가 없었으며, 다만 외해 조위가 운전정지수위에 해당할 경우에는 수평 유공판 아래에서 연직방향 흐름의 세기가 감소하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.5
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• pp.472-481
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• 2008

In this study hydraulic experiment was carried out to investigate the flow characteristics in the submerged outlet structure of Boryeong power plant and the efficiency of bubble reduction by installing horizontal porous plate in the outlet structure. The cross-sectional mean velocity in the submerged outlet structure was smaller than 1 m/s, the target value at the design stage to prevent bubble outflow to the open sea area. In addition, it was found that the maximum depth of bubble penetration is reduced 30 to 50% by installing the horizontal porous plate at the second falling location in the submerged outlet structure. It is expected that the total bubble amount entrained in the water will be most efficiently reduced by installing square-hole-shape porous plate of 20 cm hole size and making its central section as non-porous structure to dissipate the energy of falling water.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.4
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• pp.235-240
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• 2010

The foam produced by the effluent cooling water which is released to the discharge channel provokes civil complaints due to the visual pollution to the neighboring residents. In this study, a physical model test was conducted by placing tetrapods on the bottom slope of the discharge channel in order to suggest an effective method of reducing the amount of generated foam. Field application of the main results of the model test showed qualitatively apparent reduction of the foam generation at the discharge channel.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.124-129
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• 2016

This study was conducted to suggest the cause analysis and mitigation measures of foaming generated in the effluent of wastewater treatment plant. The foam generated in the outlet connected with the tidal river system was identified as structural problems. And the main cause of foaming was air entrainment by an impinging jet and the internal accumulation by the diffusion barrier. In consideration of these conditions, it present the effective ways such as micro-screen and submerged outlet, to mitigate the foaming generated in the water channel and outlet end.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.5
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• pp.452-460
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• 2008

Anti-foaming agents and foam fences have been used to remove the foam at the outfall of power plants, but there are some problems as consumption of maintenance costs and insufficiency of effect. Therefore, development of the methods how to remove the foam by stable coastal structure has been required. In this study, numerical simulation of air entrainment was carried out to design the submerged outlet structure for reducing foam using curtain walls. The air entrainment rate and the discharge of entrained air change according to the shape of weir and curtain wall. Hence, it is necessary to design the optimum section through comparison of each case. The optimum section which has the maximum rate of foam reduction was determined by the simulation results. In addition, it was found that the flow velocity at the submerged outlet is to be smaller than 1 m/s and the submerged depth of curtain wall is to be taller than height of the submerged outlet section.

• Korean Journal of Ecology and Environment
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• v.49 no.3
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• pp.187-196
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• 2016

This study was performed to improve the foaming generated in the effluent of wastewater treatment plant from March 2015 to July 2016. The main cause of foaming was air entrainment by an impinging jet and the internal accumulation by the diffusion barrier. Particularly, the foam growth was most active when there is low tide and larger discharge. To solve this problem, we experimented after installing fine mesh screen and the artificial channel device with underwater discharging outlet in the treated wastewater discharge channel and the outlet, respectively. As a result, the effects of foam reduction by devices ranged 85.0~92.0% and 70.7~85.6%, respectively. In addition, the foam and the noise were easily solved, first of all look to contribute to the prevention of complaints. Our device studies were applied to a single wastewater treatment plant. However, it is considered to be able to apply in other similar cases of domestic sewage treatment plants.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.173-182
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• 2018

As part of planning for waste minimization, decontamination foam has been considered as a potential application for the cleaning of radioactive contaminant. In this study, we synthesized silica particles to improve foam stability by varying synthesis parameters. Cetyltrimethylammonium bromide (CTAB) was found to influence the stability of the decontamination foam. The reason was that higher interaction between $SiO_2$ nanoparticles and surfactant at the air-water interface in aqueous solution is beneficial for foam stability. CTAB can also be used as an additive for the aggregation of silica nanoparticles. In the separation of $SiO_2$ nanoparticles, CTAB plays a critical role in the nanoparticles flocculation because of the charge neutralization and hydrophobic effects of its hydrocarbon tails.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.468-475
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• 2005

Biofilters packed with various materials have emerged as a sustainable technology for the treatment of volatile organic compounds (VOCs); however, problems including low performance and clogging are commonly encountered. Recently, a bioactive foam reactor (BFR) using surfactants has been suggested to ensure efficient and stable VOCs removal performance. This study was mainly conducted to investigate the feasibility of BFRs using toluene as a model compound. Prior to bioreactor studies, a series of bottle tests were used to select a suitable surfactant for the BFR application. Experimental results of the batch bottle tests indicated that TritonX-100 was the most appropriate one among the surfactants tested, since it showed a minimal effect on the toluene biodegradation rate while the other surfactants lowered the toluene biodegradation rate significantly. Using the selected surfactant, the BFR performance was determined by changing operating parameters including gas residence time and toluene loading. As the gas residence time increased from 0.5 minutes to 2 minutes, the toluene removal efficiency increased from approximately 50% to 80%. In addition, an increase of the toluene loading from $38\;g/m^3/hr$ to $454\;g/m^3/hr$ resulted in a decrease of toluene removal efficiency from approximately 70% to 20%. The BFR had a maximum elimination capacity of $108\;g/m^3/hr$ for toluene, which was much higher than those generally reported in the literature. The high toluene-elimination performance indicates that the BFR be a potential alternative to the conventional, packed-type biofilters. However, the limitation of toluene solubilization and foam stability at either high or low gas flow rate are still problems to be challenged.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.770-775
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• 2006

Biofilters packed with various materials commonly show problems such as low performance and clogging in a long-term operation. Recently, a bioactive foam reactor(BFR) using surfactants has been suggested to ensure efficient and stable VOCs removal performance. This study was mainly conducted to investigate the feasibility of the BFR system using styrene as a model compound. An abiotic md a biotic tests were conducted to estimate a mass transfer coefficient($K_La$) and a specific substrate utilization coefficient(k) for the BFR, showing the rate of mass transfer was greater in the BFR than in other diffuser systems. A dynamic loading test also indicated that the performance of the BFR was stable under a shock loading condition. Furthermore, the maximum elimination capacity of the BFR was determined to be 109 $g/m^3/hr$ for styrene, which was much higher than those for biofilter systems generally reported in the literature. Overall, the experimental results suggest that the BFR be a potential alternative to the conventional packed-bed biofilters.