• Journal of Animal Environmental Science
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• v.8 no.3
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• pp.153-158
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• 2002

Decolorization system using ozone was developed to reduce the pollutants and dark brown color remained in effluent of activated sludge process for pig wastewater. The results are as follows. 1. Wastewater temperature was increased during the ozone treatment from 31$^{\circ}C$ to 41.9$^{\circ}C$. 2. Oxidation reduction potential(ORP) at the beginning time was 148㎷, but it was increased to 330㎷ according to the ozone treatment. 3. 11mg/l of BO $D_{5}$ in effluent of activated sludge process was decreased to 1mg/l by ozone treatment, CO $D_{MN}$ also decreased from 83mg/l to 1.0mg/l. 4. 442 unit(dark brown color) of color in effluent of activated sludge process was changed to 6 units(colorless), and color removal efficiency was 98.6%.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.3
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• pp.187-193
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• 2004

In this study, Anaerobic sewage sludge in a batch reactor operation at $35^\circ{C}$ was used as the seed to investigate the effect of pretreatments of waste activated sludge and to evaluate its hydrogen production potential by anaerobic fermentation. Various pretreatments including physical, chemical and biological means were conducted to utilize for substrate. As a result, SCODcr of alkali and mechanical treatment was 15 and 12 times enhanced, compared with a supernatant of activated sludge. And SCODcr was 2 time increase after re-treatment with biological hydrolysis. Those were shown that sequential hybridized treatment of sludge by chemical & biological methods to conform hydrogen production potential in bath experiments. When buffer solution was added to the activated sludge, hydrogen production potential increased as compare with no addition. Combination of alkali and mechanical treatment was higher in hydrogen production potential than other treatments.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.43-48
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• 2001

Terephthalic acid and ethylene glycol resulting form the weight-reduction process of polyester make trouble in the operation of activated sludge process. Also, polyester weight loss wastewater shows high pH, high organic strength and wide variation of organic loading. Therefore, this study was conducted in order to improve treatment efficiency by activated sludge process with Pseudomonas sp degrading components of polyester weight loss wastewater. The CO $D_{Mn}$ and BO $S_{5}$ of the waste wastewater were 560~3,000 mg/$\ell$ and 8000~3,000 mg/$\ell$, respectively. pH was 11.8~12.3. COD removal efficiency by activated sludge-coagulation process with Pseudomonas sp was 94.1~95.8% for 35 hr of hydraulic retention time. Total organic carbon removal efficiency was 97.1%. Ethylene glycol and terephthalic acid in the wastewater were completely degraded during 32 hr of hydraulic retention time.e.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.57-61
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• 1992

This study was made for enhanced removal of N and P by intermittented aeration Activated Sludge Process. Experiment were conducted to find the effects of aeration interval and nutrient removal efficiency. When applied aeration interval were 30~60 min, 2~4 h, 4~8 h, organic matter was not affected while phosphorous removal was aeration interval 30~60 min. Also, when applied mixing intensity were 15, 30, 45 and 60 rpm, organic matter was not affected while removal was maximum at 15 rpm. Total nitrogen and phosphorous removal were in the range of 76 and 85%. Density and MLSS of Sludge were in the range of 2.3~2.6 and 7198~7810 mg/l. Release of phosphorous from activated sludge under unaerobic condition was increased as pass time.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.571-579
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• 2004

There is a need to improve the efficiency of the existing sanitary treatment facilities, because the effluent standard becomes more stricter and septic sludge increased. Thus, operating processes of sanitary treatment system in M city changed with installation of additional facilities. Process modifications were as follows: Dilution water was added to the next process after primary aeration tank. Some secondary sedimentation sludge was recycled to primary aerator so that most of the organics were stabilized in primary aeration tank under automatic control of dissolved oxygen. The line of effluent from dewatering process flowing to the activated sludge tank was changed to the primary aerator. The primary sedimentation sludge line was linked to a thickener. Polymer was added to the activated sludge tank. The effluent of primary aerator and aerobic digester was recycled from the 5th to the 1st sector. As consequencies of above process modifications, the improvement of removal efficiency was achieved as BOD 54%, COD 42%, SS 61%, T-N 39%, and T-P 12%, respectively.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.15-21
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• 2003

Two microbial communities of activated sludge in the same municipal wastewater, but treated with different systems, were studied and compared using molecular microbiological approaches. The bacterial 16S rDNA sequences from 124 clones were analyzed, however, the majority of them were not closely related to any known species, and found to belong to 8 different phylogenetic groups and 3 different unidentified groups. The relative frequencies of each group were similar between the two microbial communities. Fingerprinting using terminal restriction fragment length polymorphism (T-RFLP) showed that the putative Nitrospira-related populations were more diverse and quantitatively higher in the KNR process system than in the other system using a conventional activated sludge process. The relationship between the bacterial community composition and the higher removal efficiency of nitrogen and phosphorus in the KNR process is discussed.

• Environmental Engineering Research
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• v.25 no.3
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• pp.400-408
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• 2020

Hydrodynamic study of Activated Sludge Process (ASP) is important to optimize the reactor performance and detect anomalies in the system. Residence time distribution (RTD) study has been performed using LiCl as tracer on a pilot scale aeration tank (AT) and ASP, treating the pulp and paper mill effluent. The hydraulic performance and treatment efficiency of the AT and ASP at different operating parameters like residence time, recycle rate was investigated. Flow anomalies were identified and based on the experimental data empirical models was suggested to interpret the hydrodynamics of the reactors using compartment modelling technique. The analysis of the RTD curves and the compartment models indicated increase in back-mixing ratio as the mean hydraulic retention time (MHRT) of the tank was increased. Bypassing stream was observed at lower MHRT. The fraction of dead zone in the tank increased by approximate 20-25% with increase in recycle rate. The fraction of the stagnant zone was found well below 5% for all performed experiments, which was under experimental error. The substrate removal of 91% for Chemical oxygen demand and 96% for Biochemical oxygen demand were observed for the ASP working at a hydraulic mean residence time 39 h MRT with a 20% recycling of activated sludge.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.304-310
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• 2007

The purpose of this research was to investigate the effects of the co-treatment of municipal wastewater with microwave-irradiated excess sludge on the treatment efficiency and excess sludge production of the activated sludge process. When 250 mL of excess sludge with a MLSS concentration of approximately 2,000 mg/L was microwave-irradiated at $20^{\circ}C$ for $40\sim300$ sec by a microwave oven (2,450 MHz, 700 W), the temperature of the sludge increased at a rate of approximately $20^{\circ}C/min$ and the SCOD, TKN and T-P concentrations of the sludge showed the highest increase in the irradiation time of $40\sim130$ sec. And, the oxygen uptake rate measurement of the sludge microorganism suggested most of the microorganisms in the sludge were destroyed at an irradiation time above 130 sec(above $65^{\circ}C$). When the municipal wastewater and microwave-irradiated excess sludge was co-treated by the activated sludge process, almost no effect was observed in the pH and alkalinity of both the influent and effluent, but the influent concentrations of SS, COD, T-N and T-P increased. Even though the effluent SS, BOD and T-P concentrations showed almost no effect, the COD and TKN concentrations increased. The microbial yield coefficient decreased at a rate of 0.91 g SS/g COD removed as the irradiation ratio increased at a rate of 1 g SS/g SS-day.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.150-152
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• 1998

Now the lack of water is serious problem all over the world because of the growth of population and expansion of industrial activities. So wastewater recycle and reuse is essential in many countries. One of the most popular wastewater treatment processes is conventional activated sludge system. In spite of significant degree of treatment rate the biological process has some operational difficulties and capital disadvantages. In conventional activated sludge process, sludge settling condition is getting worse in case of sludge bulking, it is common that overall process fails due to wash-out of biomass causing low concentration of MLSS in the aeration tank. Because of the absence of claifier the membrane bioreactor(MBR) process is less affected by such problems.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.209-212
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• 1990

The activated sludge process is a commonly used method for treating sewage and waste waters. The process is characterized by a lack of measurement instrumentations and control goals that are neither well defined nor well understood. In the present study the concept of fuzzy control is employed for such process in which a design method for fuzzy controller based on a multivariable fuzzy reasoning algorithms is investigated and then simulation results are presented.