• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.3
• /
• pp.315-323
• /
• 2003

The goal of this study if the optimization of discharge electrode for pulsed corona discharge reactor located in thermal power plant. For this purpose, we have performed experiments of NO$_{x}$ removal rate by exchange of discharge electrode diameter and arrangement of discharge electrode in the non -thermal plasma reaction facility using a ethylene as additive. If the diameter and numbers of discharge electrode were larger, the NO$_{x}$ removal rate was higher. From these results, if we optimized the shape and installed numbers of discharge electrode at the pilot plant, we could increase the NO$_{x}$ removal rate with less amount of additive than current amount.mount.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.4
• /
• pp.110-116
• /
• 1999

This study was conducted to investigate the contaminants removal efficiency and the optimal operating parameters by the internal recycle rate (IRR) in the combining A2/O process with fixed film. The average removal efficiency of BOD and COD was 92.5%~94.6%, 73.9%~87.0% in RUN 1 and 91.9%~94.7%, 77.7%~89.0% in RUN 2, respectively. Organic removal efficiency, at two different hydraulic retention time of 10 and 14hr, was similar. At 50% of the internal recycle rate, organic removal efficiency was somewhat higher than the other. Total nitrogen (T-N) and total phosphorus (T-P) were removed, highly, at 50% of internal recycle rate. It could be suggested by this study that the optimum internal recycle rate is 50% and hydraulic retention time is 14hr.

• Journal of Korean Society of Water and Wastewater
• /
• v.14 no.1
• /
• pp.76-83
• /
• 2000

This research is about wastewater containing non-biodegradable TDI(Toluene Diisocyanate) that is treated by the activated carbon adsorption method. In the case of the Fenton oxidation process being applied to the existing process, optimal pH, reaction time, chemical dosing amount, removal rate, and cost were investigated. A pilot plant test was applied after finding optimal conditions with lab experiments. The optimal conditions were pH 3~5(COD removal rate 84~88%) and reaction time 30min~1hr. In higher $H_2O_2$ dosing amount, COD removal rate was a little higher. But there was little difference in the removal rate according to $FeSO_4{\cdot}7H_2O$ dosing amount. Treatment cost was economical in the case of the Fenton oxidation process being operated earlier than activated carbon adsorption system. But chemical dosing point, chemical mixing effect, chemical dosing amount, removal rate, and the cost of facility and others must be considered in practical process.

• Journal of Urban Science
• /
• v.8 no.2
• /
• pp.29-34
• /
• 2019

Benzene pollution is becoming increasingly serious, and the treatment technology of benzene has attracted much attention. In this paper, a self-made photocatalytic reactor was used to explore the removal rate of benzene under the ultraviolet light with the wavelength of 253.7nm. The results showed that the degradation rate of benzene decreased from 64.29% to 16.26% when the concentration increased from 43mg/㎥ to 256mg/㎥ under the condition of 28W UV light intensity and 50s residence time. Under the condition of 28W UV light intensity and 103mg/㎥ concentration, the residence time increased from 16.5s to 50s, and the benzene removal rate increased from 13.23% to 42.72%.Under the condition of benzene concentration 103mg/㎥ and residence time of 50s, the removal rate of benzene increased from 29.34% to 52.58% in the process of UV light intensity rising from 28W to 48W.It is concluded that decreasing the concentration and increasing the residence time of gas were beneficial to the removal of benzene and increasing the light intensity can improve the removal rate of benzene.

• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.6
• /
• pp.751-759
• /
• 2013

This study is carried out to get the basic design parameters for phospate removal facilites from wastewater by Tobermolite. The phosphate removal by the apatite formation on the surface was affected by several important factors, temperature, ions present in wastewater stream, contact time, recirculation rate, and etc. In case of the temperature, with the increase of temperature, the apatite formation was accelerated. When temperature increased from $15^{\circ}C$ to $35^{\circ}C$, removal efficiency of phosphate increased from 83 % to 93 %. An increase of calcium and fluoride ion content increase the apatite formation, however, bicarbonate and magnesium ion inhibited the crystallization of apatite. As expected, when the recirculation rate was increased from 1 Q to 3 Q, at EBCT (Empty Bed Contact Time) 60min enhanced removal efficiency was observed. The more the recirculation rate increased, the more the removal efficiency increased. According to the results of column experiment using an actual wastewater with low and high phosphate concentration (5 mg/L and 50 mg/L-P), the removal efficiency was 77 % at EBCT of 45 min, and 80 % at 60 min. It was suggested that optimum EBCT was 45 min.

• Journal of Korean Society on Water Environment
• /
• v.16 no.4
• /
• pp.501-512
• /
• 2000

This study was carried out to develop the new process for RBC process which is capable of nutrient removal and to obtain its design parameters for Sludge Settling Type Rotating Biological Contactors by comparing RBC with RBC combined with HBR (Hanmee Bio-Reactor). To achieve more than 90% of organic removal efficiency, organic loading rate less than $6.0g\;BOD/m^2/d$ is recommended. Nitrification rate was about 90% at $6.0g\;BOD/m^2/d$. TN removal efficiency of RBC+HBR was higher than those of RBC1 and RBC2. TN removal efficiency at condition of $5.0g\;BOD/m^2/d$ was about 60% in RBC1. When BOD loading rate was $6.0g\;BOD/m^2/d$. TN removal efficiencies in RBC2 and RBC+HBR were about 70%, 80%, respectively. TP removal efficiency was more than about 67% for RBC1, about 63% for RBC2 and about 71 % for RBC+HBR at the same loading rate. From the blank experiment to observe removal efficiency in the first stage, it can be known that COD removal efficiency was about 30% and suspend solids settling rate was about 45%. It was proved that RBC+HBR is much better in sludge dewatering than RBC.

• Clean Technology
• /
• v.15 no.4
• /
• pp.280-286
• /
• 2009

To evaluate the feasibility of electrodialysis for nitrate-nitrogen removal from wastewater, the effect of operating parameters on the removal of nitrate-nitrogen was experimentally estimated. The limiting current density (LCD) linearly increased with the nitrate concentration and the flow rate. The time when the nitrate concentration of diluate reached at 20 mg/L was linearly proportional to concentration of diluate, and the concentration of concentrate did not affect the removal rate. Increase in the flow rate gave a positive effect on the removal rate and became insignificant at How rates greater than 1.6 L/min. The removal rate increased with the applied voltage, but the increment in the removal rate decreased as the applied voltage approached the LCD. From the operation of the electrodialysis module used in this research, the flow rate of 1.6 L/min and the voltage corresponding to the 80~90% of LCD were found be the optimum operating condition for the nitrate removal from highly concentrated nitrate-nitrogen solutions.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.649-654
• /
• 2000

Field experiment was performed from August 1996 to June 2000. The pilot plant was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the treatment basin. The treatment basin was composed of sand and reed. Average removal rate of BOD, SS was about 75.9%, 73.4%, respectively. T-P removal rate was about 47.3%, and T-N removal rate was 19.6%. The reason for poor T-N removal might be due to high influent concentration and short retention times. As operation period increased, BOD removal rates were increased, and SS and T-P removal rates did not change significantly, but T-N removal rates were decreased.

• KSBB Journal
• /
• v.13 no.2
• /
• pp.141-146
• /
• 1998

To remove the low concentration of methane biologically, a three phase fluidized bed bioreactor immobilized with Methylosinus trichosporium OB3b was used. Optimum pH, temperature and bed height for the operation were pH7.0, 30$^\circ C$ and 150cm, respectively. For the inlet methane concentration of 100-400ppm and flow rate of 2-4L/min, the removal efficiencies of the bioreactor using the activated carbon as a carrier were the range of 54-71%, whereas those using the biosand were the range of 45-56%. It was found that activated carbon was more efficient than the biosand for the removal of methane. When aeration tank was equipped with the bioreactor, the removal efficiency increased to 6-13% and maximum removal rate obtained in the experiment was 1184mg.CH$_4$/min.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.11
• /
• pp.46-52
• /
• 2004

CMP (Chemical-Mechanical Polishing) is a process in which both chemical and mechanical mechanisms act simultaneously to produce the planarized wafer. CMP process is an extensive usage and continuing high growth rates in the semiconductor industry. The understanding of the process, however, is much slower. The nature of material removal from the wafer is still undefined and ambiguous. Material removal rate according to the slurry flow rate is also undefined and ambiguous. Thus, in this study, the basic mechanism of material removal rate as slurry flow rate is defined in terms of energy supply and energy loss.