• The Journal of Bigdata
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• v.4 no.2
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• pp.61-71
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• 2019

Chemical Mechanical Planarization (CMP) process that planarizes semiconductor wafer's surface by polishing is difficult to manage reliably since it is under various chemicals and physical machinery. In CMP process, Material Removal Rate (MRR) is often used for a quality indicator, and it is important to predict MRR in managing CMP process stably. In this study, we introduce prediction models using machine learning techniques of analyzing time-series sensor data collected in CMP process, and the classification models that are used to interpret process quality conditions. In addition, we find meaningful variables affecting process quality and explain process variables' conditions to keep process quality high by analyzing classification result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.179-180
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.27-28
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• 2011

• Membrane Journal
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• v.23 no.6
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• pp.460-468
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• 2013

This study reviewed optimum dosage rate of coagulant and ability to remove dissolved organic carbon without sedimentation in conventional water purification plant. It was confirmed that floc formated by pre-treatment process was broken by impeller of booster pump. Optimum dosage rate of coagulant was 4 mg/L (as PACl 17%) for floc formation through blend, coagulation and after passing through the pump when turbidity of raw water was less than 10 NTU. And average removal rate of dissolved organic carbon was 43% at that time. Maximum removal rate of dissolved organic carbon was 48%, even though coagulation rate was increased gradually until 8 mg/L (as PACl 17%). So removal rate of dissolved organic carbon is not much improved even if dosage rage of coagulant increase. TMP of PVDF (polyvinylidene flouride) pressurized MF process without pre-treatment operated at 0.54 bar and TMP of PVDF pressurized MF process with pre-treatment operated at 0.41 bar.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.383-390
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• 2011

In this study, a process combined biofiltration with sulfur-utilizing autotrophic denitrification and membrane separation was proposed to examine the efficiency of nitrogen removal. As an experimental device, hollow-fiber module was installed in the center of reactor to generate the flux forward sulfur layer in the cylinder packed with granular sulfur. In addition, a simple module was installed in activated sludge aeration tank which inside and outside of sulfur-using denitrification module was covered with microfilter and the module was considered as an alternative of clarifier. The experiment for developing new MBR process was carried out for three years totally. As the results of first two-year experiment, successful nitrogen removal performance was revealed with lab-scale test and pliot scale plant using artificial wastewater and actual plating wastewater. In this year, pilot scale test using actual domestic wastewater was performed to prove field applicability. As the results, high-rate nitrogen removal performance was confirmed with about 0.19 kg ${NO_3}^--N/m^3$ day of rate. Also significant fouling and pressure increase were not found during the experiment. And, the production ratio of sulfate and the consumption ratio of alkalinity showed a slightly higher value about 311 mg ${SO_4}^{2-}/L$ and 369 mg $CaCO_3$/L, respectively. In conclusion, the developed MBR process can be utilized as an alternative for retrofiting existing wastewater plants as well as new construction of advanced sewage wastewater treatment plants, with cost-effective merit.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.563-570
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• 2004

Phased isolation intrachannel clarifier ditch process developed in this study is an enhanced biological nutrient removal process employing two ditches with intrachannel clarifiers. Bench-scale phased isolation ditch process was used to evaluate the system performance on municipal wastewater and detailed assessment of internal behavior in a ditch and each reactions. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31 days, and cycle times of 4hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 73~78%, and 65~90%, respectively. The internal behavior were well matched on each reactions such as nitrification, denitrification, and phosphorus release and uptake. As the SRT became longer, TN removal increased gradually, whereas TP removal decreased contrarily. However, the system was capable of producing an effluent TP concentration 1mg/L or less even at longer SRTs except the case of solids discharge by malfunction of intra-clarifier occurred by its geometrical limit. The system performance slightly decreased by hydraulic shock loading(increasing of influent flowrate and decreasing of system HRT). However, the higher system performance could be achieved again after four cycles. Thus, the system reliability could be successfully achieved short-term hydraulic shock loading that occurred in medium- and small-sized wastewater treatment plants suffering fluctuation of influent quality and flowrate during wet season.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.1
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• pp.1-14
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• 2021

Eutrophication and algal blooms can lead to increase of taste and odor compounds and health problems by cyanobacterial toxins. To cope with these eco-social issues, Ministry of Environment in Korea has been reinforcing the effluent standards of wastewater treatment facilities. As a result, various advanced phosphorus removal processes have been adopted in each wastewater treatment plant nation-widely. However, a lot of existing advanced wastewater treatment processes have been facing the problems of expensive cost in operation and excessive sludge production caused by high dosage of coagulant. In this study, the sedimentation and dissolved air flotation (SeDAF) process integrated with sedimentation and flotation has been developed for enhanced phosphorus removal in wastewater treatment facilities. Design and operating parameters of the SeDAF process with the capacity of 100 ㎥/d were determined, and a demonstration plant has been installed and operated at I wastewater treatment facility (located in Gyeonggi-do) for the verification of field applicability. Several empirical evaluations for the SeDAF process were performed at demonstration-plant scale, and the results showed clearly that T-P and turbidity values of treated water were to satisfy the highest effluent standards below 0.2 mg/L and 2.0 NTU stably for all of operation cases.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.606-612
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• 2022

The purpose of this study is to convert hydrophobic dyestuff to hydrophilic dyestuff by reacting cationic collector with anionic dyestuff and reaction anionic collector with cationic dyestuff. The removal of colors from aqueous solutions and/or dispersions has been studied by dispersed-air flotation in a batch column. In this studies used generated micro bubble by ceramic gas diffuser having micro pore size for air flotation process. In this study, a ceramic gas diffuser with micro pore size was used to generate micro bubbles for the air flotation process. Two colours were used for the experiments: Basic Yellow 1 (cationic dyestuff) and Direct Orange 10 (anionic dyestuff). All two were effectively removed by flotation within 8 mins. Sodium dodecyl sulfate, sodium oleate (an anionic collector), and amines (a cationic collector) were found to be effective as collectors in the removal of color, which was found to be related to the pH of the solution and the amount of collector added to it, with high collector dosages causing the process to become pH-independent.

• Journal of Animal Environmental Science
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• v.9 no.2
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• pp.85-92
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• 2003

These experiments were conducted to evaluate the efficiency of the color removal treatment system of pig wastewater by $TiO_2$. The results obtained are summarized as follow ： 1 The color removal efficiency of effluent of activated sludge process by $TiO_2$ level were 59.7 and 52.5% for 1.0 and 2.0g/$\ell$ at 360 minute of operation time, respectively. 2. The color of pig wastewater was changed from 655 color unit(cu) to 146cu of the wastewater treatment of pH 5 at 300 minute of operation time. 3. The $H_2O_2$ level for color removal showed at 200mg/$\ell$ and in that level, the color removal efficiency was 52.5%. 4. The color removal efficiency of 365nm UV intensity was 29.4%, but 254nm of UV intensity was higher(50.1%) than 365nm for color removal.

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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• pp.189-193
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• 1996

Submicron-sized polymeric particles (SSPP) were used to remove nucleic acids and endotoxins from cell lysates. The positively charged SSPP selectively adsorb nucleic acids and endotoxins and form complexes with them. The complexes can be easily removed by sedimentation or centrifugation. The removal of nucleic acids and endotoxins using SSPP also can be accomplished in the presence of cell and cell debris. Therefore, nucleic acids and endotoxins can be removed in an initial step of the down-stream processes. In bakers yeast and E. coli lysate systems, the level of DNA could be reduced more than three orders of magnitudes and endotoxins more than seven orders of magnitudes concurrently willi the cell debris removal process using SSPP.