• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.43-49
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• 1997

This study was aimed to estimate removal efficiency(%) of BER(Biofilm-Electrode Reactor) and A.S(Activated Sludge) treatments. When were analyzed COD$_{Cr}$, NH$_3$-N and T-P by current density and reaction time, the results were as follows : 1) In BER treatment, the removal efficiency of COD$_{Cr}$ in domestic wastewater was 79-86% when current density was 2.39 mA/dm$2$(15mA)-3.98 mA/dm$^2$(25mA) and reaction time was 48 hr. 2) Removal efficiency of NH$_3$-N was 71-73% when current density was 2.39-3.98 mA/dm$^2$ and reaction time 48 hr. 3) When the reaction time was 48 hr removal efficiency(%) of BER treatment for COD$_{Cr}$, NH$_3$-N and T-P were more excellent than A.S. treatment. And then we prospect that was because activated microorganism colonies attached in biofilm on surface of electrode pannel. Therefore, In order to derive BER treatment efficiency(%) should establish optimum conditions of pH, temp., reaction time, current density and biochemical and electrochemical states.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.99-107
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• 2018

In order to design the improvement process for T-N removal, the treatment process of Suyoung, Gangbyeon, and Noxan sewage treatment plants (STP) in Busan was anlayzed. Suyoung STP shows a T-N removal efficiency of about 69.8% with MLE(Modified Ludzack ettinger) and A2O+MBR. However, it is necessary to improve the process to maintain over DO of 1 mg/L and is required to install a flow control tank to minimize the rainfall effect. Gangbyun STP shows a about 70.2% T-N removal efficiency with A2O+GFF(gravity fiber filtration). However, in order to improve T-N removal efficiency, it is needed to install MLE process to treat recycle water. Noksan STP shows a T-N removal efficiency of about 71.0% with MLE+Chemical treatment and shows stable T-N concentration in effluent. However, it is required a toxic chemical management process because bad wastewater flows into the STP, also is necessary a process improvement in order to increase internal recycling ratio. Especially, it is required a process improvement to increase HRT of nitrification tank because Suyoung and Gangbyeon STPs shows low nitrification efficiency during winter season.

• Journal of environmental and Sanitary engineering
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• v.11 no.3
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• pp.37-46
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• 1996

In this study, the effect of pH, Temp, dye concentration, distance of electrode, and the potential on the removal efficiency of dye-wastewater using electrochemical reaction were investigated. Optimum conditions for the electrochemical treatment of dye-wastewater were obtained that pH;7, 8V, electrode distance; 1cm and the reaction time for obtaining above 99% removal efficiency were 10 - 40min at each conditions, From this result, we can determine the instantaneous current efficiency and specific energy consumption, and we can provide the effective data for economical treatment of industrial dye-wastewater.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.62-75
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• 2000

Most of biological treatment to remove contaminants in municipal wastewater have been conducted by activated sludge process. But, the process have several probIems such as enormous site needed for construction of treatment facilities, unstable treatment due to limited ability to control load fluctuation, frequent sludge bulking and appearance of lots of surplus sludge. In this study, the experiments were performed through submerging biofilm of PEPP media in existing aeration tank with raw water from municipal wastewater treatment plant and then submerging PVDC and PEPP media, different from shape and chemical peculiarity in anoxic reactor. Throughout the experience, nutrient removal efficiency according to HRT, nitrogen phosphorous removal efficiency, behavior of nitrogen and dewatering efficiency have been compared and analysed with those of activated sludge process. As the results, BOD removal efficiency according to BOD volumetric load and F/M ratio was not found any differency in two processes, but was decreased below 90% as going along the condition of high load in activated sludge process. Kinetic coefficient was $K_{max}=1.162day^{-1}$, $K_s=53.77mg/L$, $Y=0.166mgVSS/mgBOD_{rem}$. and $K_d=0.019day^{-1}$. It was found that the removal efficiency, even though in aerobic condition, in biofilm process equipped anoxic reactor was higher than the one in activated sludge process within the range of 70~80%, and became better as HRT increased. Phosphorous removal efficiency was not found any differency in two processes. In biofilm process, treament efficiency even in conditions of high load was not decreased, because the biomass concentration could be maintained in high condition compared with activated sludge process. As HRT increased, suspended and attached biomass was increased and the other hand, F/M ratio was decreased as biomass' increasing. Biomass thickness was increased. from $10.43{\mu}m$ to $10.55{\mu}m$ as HRT increased and density of biomass within $40.79{\sim}41.16mg/cm^2$. The results also present that the dewatering efficiency of sludge generated in biofilm process was higher than in activated sludge process, and became better as HRT increased.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.31-36
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• 2000

Conventional membrane systems was difficults to treatment for the swine waste water. Technological advances in membrane filtration systems have created opportunity for the swine wastewater to treat effluent streams in order to meet stricter environmental constraints. "Vibratory Shear Enhanced Processing(VSEP)" developed by new logic international makes it possible to filter effluent streams without the fouling problem exhibited by conventional membrane systems. Various kinds of waste water occurred to and swine wastewater experiment with "VSEP" set up conventional reverse osmosis membrane (ACM-4, ESPA, BW-30). The results were as followes : Treatment efficiency for the input COD(From $332mg/{\ell}$ to $4,968mg/{\ell}$) was 98%. Treatment efficiency for the input SS(From $140mg/{\ell}$ to $4,040mg/{\ell}$) was 100%(All together). Treatment efficiency for the input T-N(From $155mg/{\ell}$ to $934mg/{\ell}$) was 97%~99.8%. Treatment efficiency for the input T-P(From $28.6mg/{\ell}$ to $132mg/{\ell}$) was 99.7% and up. ESPA membrane excels three types of reverse osmosis membranes applied VSEP in removal efficiency.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.109-120
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• 1997

The purpose of this study is to evaluate the effectiveness of wastewater treatment containing surfactant. For that, comparative analysis of effectiveness of Featon Oxidation, Aluminum Sulfate, PAC (Poly Aluminum Chloride) on the treatment of the synthetic wastewater containing LAS (Linear Alkyl Sulfate), a main component of the commercial detergent was carried. Then, the optimum pH, the dosage of reagents, and the concentration of the LAS in each treatment were determined. The results of the study were summarized as following. 1. In Fenton Oxidation, optimal pH was 3 and 97.92% removal of LAS was achieved. However, the increase of the pH reduced the efficiency of LAS removal. The proper chemical dosages of FeSO$_4$ and $H_2O_2$ were 300 mg/l and the increase of dosages didn't affected the removal efficiency. Therefore, it was concluded that the economic chemical dosage was 300 mg/l of FeSO$_4$ and $H_2O_2$. 2. In case of Alum treatment, optimal pH was 11 with 61.13% removal efficiency. At other pH range, the removal efficiency was very low indicating that removal efficiency is greatly influenced by pH. The proper chemical dosage was 200 mg/l with the removal efficiency of 77.65%. The increase of chemical dosage, however, reduced the removal efficiency. 3. In case of using PAC, optimal pH was 6 with 97.99% removal efficiency. The result showed that wastewaters containing surfactant were almost completely removed at pH 6 by PAC. Removal efficiency was decreased by increasing PAC dosage higher than 400 mg/l and dosage over 700 mg/l of PAC abolished the treatment. 4. The comparative analysis of three methods revealed that the effective pH ranges were at pH 2-5 with Fenton oxidation, at pH 6-11 with PAC, and pH 11 with Alum. The removal efficiencies at these pH were 83.95-97.92%, 75.98-97.99% and 61.13%, respectively. 5. Increase in LAS concentration reduced the removal efficiencies of all three methods. In the case of PAC or Alum treatment, treatment abolished at LAS concentration higher than 700 mg/l.

• Journal of Industrial Technology
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• v.18
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• pp.1-6
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• 1998

This study was conducted to use disused vinyl as biofilm for biological sewage treatment. Efficiency verification was performed on laboratory and on-site plant. In laboratory study, total biochemical oxygen demand(TBOD) removal rate was ranged 94.8~97 % in each hydraulic retention tim(HRT), 12, 16, 20, 24 hr, respectively. At that time, filling rate was 50 %. And effluent TBOD concentration was low ranged 3.64~6.28 mg/L. In on-site plant, TBOD removal rate was ranged 88.2~96.8 % and effluent TBOD concentration was 4.8~17.7mg/L. This concentration was lower than disign effluent concentration, 30mg/L. Total kjeldhal nitrogen(TKN) removal efficiency was ranged 56.8~90.9%. This was resulted higher than Lab. scale treatment efficiency.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.139-146
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• 1998

The characteristics of color and COD removal for dyeing-wastewater using electrochemical reaction were investigated. >From the result, the removal efficiency of color and COD were increased with increase of temperature, decrease of electrode distance, increase of electrolyte concentration and increase of potential and these were obtained above 99%, above 75% within 30 min, individually. Cause of higher COD removal efficiency, it is more suitable that dyeing-wastewater is treated by electrolytic treatment prior to biological treatment. It is concluded that the electrolytic treatment of dyeing-wastewater can be used as the effective and economical method in practical treatment.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1291-1292
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• 2008

ITO is widely used as an anode material in OLED, because of its good transparency, low electrical resistivity, high work function, and efficient hole injection properties. The interface between the electrode and the organic layer in the OLED effects the charge injection process and may influence the electrical and the luminance properties. Surface treatment of ITO, such as an Aquaregia treatment has been shown to enhance the efficiency, and luminance characteristics of the OLED. In this study, we investigated the effect of Aquaregia treatment. The fundamental structures of the OLED were ITO/NPB/$Alq_3$/LiF/Al. The current density-voltage-luminance, efficiency, and lifetime characteristics were measured with untreated and Aquaregia-treated ITO substrates. The Aquaregia treatment was found to enhance the performance of OLED. For the Aquaregia treated device, the maximum luminance and efficiency were increased by about 2 times compared to the untreated device. The mechanism of the Aquaregia treatment is discussed based on AFM analyses.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1566-1570
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• 2013

In this paper, we analyzed the electric characteristics of the OLEDs device of which anode ITO has been treated with the oxygen plasma. We fabricated the basic three-layer structure (ITO / AF / $Alq_3$ / $Cs_2CO_3$ / Al) device, analyzed how the oxygen plasma treatments of the ITO surface affects to the electrical characteristics of OLEDs. We also produced a four-layer structure device (ITO / AF / TPD / $Alq_3$ / $Cs_2CO_3$ / Al) with the oxygen plasma treatment. From the comparative analysis to the devices, we confirmed following results. The three-layer structure OLEDs device with oxygen plasma treatment has better characteristics than the device without the treatments; maximum luminance, luminous efficiency, and external quantum efficiency are improved approximately 151 [%], 126 [%], and 175[%], respectively. Also, the electric characteristics of the four-layer structure device with oxygen plasma treatment are improved comparing to the characteristics of the three-layer structure device with oxygen plasma treatment; maximum luminance, luminous efficiency, and external quantum efficiency are improved approximately 144 [%], 115 [%], and 124[%], respectively.