• Proceedings of the Membrane Society of Korea Conference
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• 1998.06a
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• pp.113-133
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• 1998

In activated sludge process, sludge settling condition is affected by organic loading rate or operation condition, and if settling condition is getting worse, it is common that overall process fails due to wash-out of biomass causing low concentration in the aeration tank. Also activated sludge process has such several problems as requiring large area, consuming a lot of power and producing large volume of sludge. Increased public concern over health and the environment combined with a strong desire to reduce capital, operating and maintenance costs, have created a need for innovative technologies for building new high quality effluents which vail meet 21st century crkeria. MBR(Membrane Bioreactor) process consists of a biological reactor and ultrafiltration(UF) membrane system that replaces the conventional clarifier of an activated sludge process. The main operating advantages of this system are that the quality of the effluent is independent of the settleability of the mixed liquor and that the effluent is free of suspended solids in any operating condition. It is possible to eliminate clarifier and to reduce the volume of aeration tank because it can afford to accumulate high biomass concentration in the bioreactor(20, 000~30, 000mg/L), which would not be possible in a conventional activated sludge process. Therefore, this process reduces overall treatment plant area. In addition to those advantages, Longer SRT condition enables higher sludge digestion in MBR process so the sludge volume produced is 50 to 70% lower than that of conventional activated sludge process There are two kinds of MBR process according to the allocations of membrane. One is cross flow type MBR of which module is located outside of the bioreactor and mixed liquor is driven into the membrane module. The other is submerged type MBR process of which module is submerged in the bioreactor and mixed liquor is generally sucked from the lumen side. addition to that the cake layer is often removed by the uplifting flow of bubbling air. A submerged MBR process is superior to a crossflow MBR in regard to the power consumption because suction pressure of a submerged MBR is generally lower than that of a crossflow MBR which has recirculation pump. A submerged MBR, therefore, has the potential to be applied to small wastewater treatment plants that need low cost treatment systems.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.717-725
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• 2002

A bench-scale submerged-type membrane filtration system (SMFS) was constructed to study a feasibility of membrane filtration for solid-liquid separation in water and wastewater treatment processes. In the case of applying the SMFS to a biological wastewater treatment process, so-called membrane bioreactor, aeration underneath membrane modules is usually employed in order to provide oxygen demand for microbial growth as well as to control membrane fouling. A study was investigated the effects of operation parameters by aeration intensity, feed concentration, foulant type and airlift pore size on critical flux. Critical flux tends to increase with aeration rate. Optimal aeration flow rate was found to be 10 L/min/module. Feed concentration and foulant type has a significant effect on membrane fouling and filtration performance. But downward position and pore size of airlift has no a significant effects on membrane fouling and filtration performance.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.997-1002
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• 2007

The objectives of this research are to remove dissolved organic matter and nitrogen compounds by using aerated submerged bio-film(ASBF) reactors in batch systems and improve understanding of dissolved organic matter and nitrogen compounds removal rates with dynamic relationships between heterotrophic and autotrophic bacteria in the fixed-film reactor. This research explores the possibility of enhancing the performance of shallow wastewater treatment lagoons through the addition of specially designed structures. These structures are designed to encourage the growth of a nitrifying bacterial bio-film on a submerged surface. Specially, the effects of cold temperatures on the dissolved organic matter and ammonia nitrogen performance of the ASBF pilot plant was investigated for the batch system. It is anticipated thai the ASBF would be used for a design of biological treatment for removing of dissolved organic matter and nitrogen compounds in new wastewater treatment plants as well as existing wastewater treatment plants.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.107-115
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• 2008

Herbs and plants widely used for the ecological restoration were selected for germination rate analysis under treatment of microorganisms to determine ideal treatment conditions and medium for enhanced germination rate. Albizzia julibrissin, when submerged in a nutrient medium or distilled water, presented a decrease in germination period rather than increase in germination rate. When treated with microorganism culture solution (JM-2) for 24 hours, 90% germination was achieved in two days, which is sufficient evidence to conclude that such treatment accelerates the germination of Albizzia julibrissin. Germination period decreased for Lespedeza cyrtobotrya samples submerged in microorganism solution for 15 and 48 hours, however, increases in germination rates were not observed. Sample treated in the solution for 24 hours had increased germination rate and enhanced germination period. Microorganism solution treatment had a negative effect on germination for Lespedeza cuneata, unlike Lespedeza cyrtobotrya and Albizzia julibrissin. Microorganism treated seeds of Lepsedeza cuneata had a lower germination rate than that of the control with no treatment. However, submerging treatments in a nutrient medium or distilled water for 24 to 48 hours were proven effective with higher germination rates than control sample with no treatment. Herbs and plants widely used for the ecological restoration were selected for germination rate analysis under treatment of microorganisms to determine ideal treatment conditions and medium for enhanced germination rate. Albizzia julibrissin, when submerged in a nutrient medium or distilled water, presented a decrease in germination period rather than increase in germination rate. When treated with microorganism culture solution (JM-2) for 24 hours, 90% germination was achieved in two days, which is sufficient evidence to conclude that such treatment accelerates the germination of Albizzia julibrissin. Germination period decreased for Lespedeza cyrtobotrya samples submerged in microorganism solution for 15 and 48 hours, however, increases in germination rates were not observed. Sample treated in the solution for 24 hours had increased germination rate and enhanced germination period. Microorganism solution treatment had a negative effect on germination for Lespedeza cuneata, unlike Lespedeza cyrtobotrya and Albizzia julibrissin. Microorganism treated seeds of Lepsedeza cuneata had a lower germination rate than that of the control with no treatment. However, submerging treatments in a nutrient medium or distilled water for 24 to 48 hours were proven effective with higher germination rates than control sample with no treatment.

• Journal of Korean Society on Water Environment
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• v.16 no.4
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• pp.523-532
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• 2000

The purpose of this study was to investigate the effects of the hydraulic retention time (HRT) and organic loading rate (OLR) on microbial characteristics and treatment efficiency in sewage treatment using aerated submerged biological filter (ASBF) reactor. This reactor combines biodegradation of organic substrates by fixed biomass with a physical separation of biomass by filtration in a single reactor. Both simulated wastewater and domestic wastewater were used as feed solutions. The experimental conditions were a temperature of 17 to $27^{\circ}C$, a hydraulic retention time of 1 to 9hr, an organic loading rate of 0.47 to $3.84kg\;BOD/m^3{\cdot}day$ in ASBF reactor. This equipment could obtain a stable effluent quality in spite of high variation of influent loading rate. Total biomass concentration. biofilm thickness and biofilm mass increased an exponential function according to the increasing OLR. The relationships between water content and biofilm density were in inverse proportion. The percentage of backwash water to influent flow was almost 9%. The separation efficiency of biomass was the percentage of 91 to 92 in ASBF reactor. The sludge production rates in feed solutions of simulated wastewater and domestic wastewater were 0.14~0.26 kg VSS/kg BODrem, 0.43~0.48 kg VSS/kg BODrem, respectively.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.123-130
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• 2020

Submerged Membrane bioreactor (SMBR) is one of the last techniques that allow a high quality of treated industrial effluents by coupling biological treatment and membrane separation. Thus, this research was an effort to evaluate performance of a SMBR treating a model textile wastewater (MTWW). Different SMBR operating parameters like mixed liquor suspended solids (MLSS) and Dissolved oxygen concentration, hydraulic retention time (HRT), and nutrients addition (N and P) have been investigated. MTWW (influent to the SMBR) was generated using the reactive azo-dye, Novacron blue FNG (100mg/L feed concentration). Results of MTWW treatment using SMBR under optimal operating conditions (MLSS, 4.2-13.3g/L; HRT, 4 days; pH, 6.9-7.2; conductivity, 400-900 μS/cm and temperature, 19.4-22.2 ℃) showed that COD and blue colour treatment performances are between 94-98% and 30-80%, respectively. It is concluded that SMBR can be used in large scale textile wastewater treatment plants to improve effluent quality in order to meet effluent discharge standards.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.519-526
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• 2006

In this study, the major operating factors in SND(simultaneous nitrification and denitrification) using bioreactor packed with submerged cilia media and granular sulfur such as variation of nitrification rate, organic matter removal efficiency and denitrification efficiency in different DO concentration were mainly evaluated. Synthetic wastewater and actual sewage were used as influent wastewater. Experiment with synthetic wastewater as influent wastewater was divided into three phases with the adjustment of DO concentration. As the results, nitrification efficiency and T-N removal efficiency in the Phase 3(DO 1.0~2.0 mg/L) were 99% and 52.3%, which is significantly greater than those in other two phases. Also, loading rate and denitrification efficiency of SCPGS(Submerged Cilia media Packed with Granular Sulfur) were calculated as $0.44kg\;NO_3^--N/m^3-day$ and 50%, respectively. On the other hand, nitrification rate was decreased from 99% to 64% according to the DO concentration with the variation from 3.0~3.5 mg/L(phase1) to 0.4~0.6mg/L(phase2). Although the nitrification rate was decreased in 64% according to the variation of the DO concentration, T-N removal rate was rapidly increased to 49% by increasing of the denitrification efficiency. Experiment with actual sewage as influent wastewater was carried out to evaluate efficiency of SCPGS in real operation condition of full-scale sewage water treatment plant. At the time, T-N removal rate in this experiment and full-scale wastewater treatment plants were given by 43% and 20%, respectively. The above results indicate that SCPGS can be used as an advanced treatment process for economical efficiency considered.

• Membrane Journal
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• v.23 no.1
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• pp.45-53
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• 2013

Membrane filtration processes are increasingly popular for drinking water treatment that requires high quality of water. But pre-treatment system (Coagulation/Flocculation/Sedimentation) requires increased footprint and installation cost. In addition, 5~10% of the concentrate are formed. In this study, the pressurized PVDF membrane (ECONITY Co., Ltd.) system was tested with surface water (Han River, South Korea) without pre-treatment. As a result, permeate flux was operated between 1 m/d and 2.4 m/d (at $25^{\circ}C$) without chemical cleaning for one year and membrane permeate turbidity was maintained stably under 0.05 NTU regardless of raw water turbidity. And we studied application of concetrate treatment of pressurized PVDF membrane by submerged PE membrane (ECONITY Co., Ltd.). As a result, we increased recovery of total treatment process to 99.5%.

• Membrane and Water Treatment
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• v.1 no.4
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• pp.283-296
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• 2010

During the disinfection of potable water, humic substances present in the solution react with chlorine to form potential carcinogenic compounds. This study evaluates the feasibility of using a submerged membrane photocatalysis reactor (SMPR) process for treatment of humic substances through the characterization of both organic removal efficiency and membrane hydraulic performance. A simple SMPR was operated and led to the removal of up to 83% of the polluting humic matters. Temporal rates of organic removal and membrane fouling were found to decrease with filtration time. Using tighter membrane in the hybrid process resulted in not only higher organic removal, but also more significant membrane fouling. Under the experimental conditions tested, optimum $TiO_2$ concentration for humic removal was found to be 0.6 g/L, and increasing initial pollutant concentration expectedly resulted in a more substantial membrane fouling. The importance of the influent nature and pollutant characteristics in this type of treatment was also assessed as various water sources were tested (model humic acid solution vs. local water containing natural organic matters). Results from this study revealed the promising nature of the SMPR process as an alternative technique for organic removal in the existing water treatment system.

• 대한치주과학회:학술대회논문집
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• 1998.11a
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• pp.105-105
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• 1998