• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.10
• /
• pp.724-729
• /
• 2013

Simultaneous nitrification and denitrification (SND) occurs concurrently in the same reactor under micro dissolved oxygen (DO) conditions. Anaerobic zone was applied for phosphorus release prior to an aerated membrane bio-reactor (MBR), and anoxic zone was installed by placing a baffle in the MBR for enhancing denitrification even in high DO concentration in the MBR. Phosphorus removal was tested by alum coagulation in the anaerobic reactor preceding to MBR. DO concentration were 2.0, 1.5, 1.0, 0.75 mg/L in the MBR at different operating stages for finding optimum DO concentration in MBR for nitrogen removal by SND. pH was maintained at 7.0~8.0 without addition of alkaline solution even with alum addition due to high alkalinity in the raw sewage. Both TCODcr and $NH_4^+$-N removal efficiency were over 90% at all DO concentration. TN removal efficiencies were 50, 51, 54, 66% at DO concentration of 2.0, 1.5, 1.0, 0.75 mg/L, respectively. At DO concentration of 0.75 mg/L with addition of alum, TN removal efficiency decreased to 54%. TP removal efficiency increased from 29% to 95% by adding alum to anaerobic reactor. The period of chemical backwashing of the membrane module increased from 15~20 days to 40~50 days after addition of alum.

• Proceedings of the Korea Contents Association Conference
• /
• 2010.05a
• /
• pp.13-15
• /
• 2010

이동객체의 공간 데이터를 색인하기 위해 검색성능이 뛰어난 R-tree구조가 많이 활용된다. 최근 R-tree를 B+-tree처럼 인접한 단말노드 간의 연결을 통해 질의 처리를 수행하는 ISR-tree와 ISG-index가 제안되었다. 이 기법들은 MBR (Minimum Boundary Rectangle) 간의 인접한 이웃 노드를 결정하기 위해 보르노이 다이어그램(Voronoi Diagram)을 이용한다. MBR을 대상으로 하는 보르노이 다이어그램은 매우 복잡한 연산과정을 거친다. 본 논문에서는 점을 대상으로 하는 보르노이 다이어그램 연산을 활용한 인접한 이웃 MBR을 연산하는 기법을 제안한다. 각 MBR의 꼭지점들을 기준으로 보르노이 다이어그램을 만들 경우, 인접한 MBR의 꼭지점들의 보르노이 셀이 항상 인접한 것을 알아내었고, 이를 활용한다. 제안하는 기법의 우수성을 증명하기 위해 기존의 기법과 비교하여 성능평가를 수행하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10b
• /
• pp.108-110
• /
• 1998

지리정보시스템에서는 방대한 공간데이타를 다루는 특성 때문에 효율적인 데이터의 관리 및 검색이 매우 중요하다. 본 연구에서는 공간데이타 질의처리를 위하여 여과-정제 방법을 사용하고 여과단계에서의 효과를 높이기 위하여 MBR 연산자와 대표점 필터, 그리고 그 instance들을 제안하였으며 이를 트리기반의 인덱싱 방법과 결합한 다중필터 방법을 제안하였다. MBR 연산자와 대표점 필터는 질의영역이 convex한 영역이고 특히 객체에 비하여 충분히 큰 경우 기존의 MBR만을 이용한 처리방법에 비해 매우 효율적이다. MBR과 질의영역의 위상관계를 분석하여 필요한 정보를 질의의 종류에 따라 적절히 사용함으로써 이후의 필터 및 정제 단계에서의 후보객체의 수를 줄일 수 있고, 따라서 수행시간을 줄일 수 있다.

• Journal of Korean Society of Water and Wastewater
• /
• v.22 no.1
• /
• pp.87-92
• /
• 2008

Purposes of this study were to evaluate operational performance of submerged membrane bioreactor (MBR) combined with periodic chemical backwash. Five lab-scale submerged MBRs were performed in accordance with NaOH dose, backwash solution volume. While filtration resistance of MBR system without backwash (Control) was increased persistently from startup, those of four MBR systems (RUN 1-4) with chemical backwash were maintained at $(1.4{\pm}0.16){\times}10^{12}$, $(8.6{\pm}0.90){\times}10^{11}$, $(1.9{\pm}0.10){\times}10^{12}$, $(1.4{\pm}0.10){\times}10^{12}l/m$, respectively. Under chemical backwash condition of 0.0230 M, 375 mL, permeability of membrane was highest at flux of $30L/m^2/hr$. According to results from experiment that changing condition of dose and volume, it was estimated that effect of chemical dose acts more greatly than backwash solution volume. Because COD removal rates of all MBR systems with chemical backwash were more than 96%, it was proved that NaOH added to backwash solution did not affect microorganism.

• Membrane and Water Treatment
• /
• v.8 no.6
• /
• pp.517-528
• /
• 2017

This study evaluates the performance of membrane bioreactor (MBR) coupled with a modified walnut shell granular activated carbon (WSGAC) for tannery wastewater treatment. For this purpose, a pilot with overall volume of 80L and 12 hours hydraulic retention time (HRT) is operated in three scenarios. Here, the chemical oxidation demand (COD) of wastewater is reduced more than 98% in both C:N ratios of 13 (S1) and 6.5 (S2). This performance also remains intact when alkalinity depletes and pH reduces below 6 (S3). The ammonium removal ranges between 99% (S2) and 70% (S3). The reliability of system in different operating conditions is due to high solids retention time and larger flocs formation in MBR. The average breakthrough periods of WSGAC are determined between 15 minutes (S2) and 25 minutes (S1). In this period, the overall nitrate removal of MBR-WSGAC exceeds 95%. It is also realized that adding no chemicals for alkalinity stabilization and consequently pH reduction of MBR effluent (S3) can slightly lengthen the breakthrough from 15 to 20 minutes. Consequently, MBR can successfully remove the organic content of tannery wastewater even in adverse operational conditions and provide proper influent for WSGAC.

• Membrane Journal
• /
• v.15 no.4
• /
• pp.289-296
• /
• 2005

In the MBR process, the membrane fouling occurs seriously on the membrane surface. In general, the membrane fouling is attributed to factors such as deposition or adhesion of sludge floc. The occurrence of fouling is a main cause of a decrease in membrane module fluk. At this study, our MBR membrane is manufactured by nano-particle with excellent anti-fouling character. The fine nano-material which can repel the sludge Hoc from the membrane surface is distributed in the membrane surface. We confirm anti-fouling effect, test continuously in the pilot site.

• Membrane and Water Treatment
• /
• v.5 no.3
• /
• pp.197-205
• /
• 2014

For the first time in Bangladesh, a bench scale membrane bioreactor (MBR) unit was tested in treating a textile wastewater in the industry premises of EOS Textile Mills LTD, Dhaka for three months. The performance of the unit was compared with that of the conventional activated sludge treatment plant, which is in operation in the same premises. The COD and BOD removal efficiency of the MBR unit reached to around 90% and 80% respectively in 20 days whereas the removal efficiency of the conventional treatment plant was as low as 40-50% and 38-40% respectively. The outlet COD and the BOD level for the MBR unit remained stable in spite of the fluctuation in the feed value, while the conventional effluent treatment plant (ETP) failed to keep any stabilized level. The performance of the MBR unit was much superior to that of the functional ETP and the water treated by the MBR system can meet disposal standard.

• Journal of Korean Society on Water Environment
• /
• v.27 no.1
• /
• pp.44-53
• /
• 2011

Membrane bio-reactor (MBR) has several advantages over the conventional activated sludge process, including a high biomass, low sludge production, and better permeate quality. Therefore, the MBR have gained popularity for municipal and industrial wastewater treatment. However the MBR usually were used for sewage and low streng th wastewater treatment because of membrane fouling problem and limitation of oxygen transfer into biomass. In this study, the hybrid process combining MBR and pure oxygen was tested for high strength organic wastewater treatment in the COD loading range from 2 to $10kgCOD/m^3{\cdot}day$. The hybrid process, membrane coupled pure oxygen high compact reactor (MPHCR), had been operated for one year and operation parameters, the effect of COD loading, MLSS concentration and the location of membrane module were studied for membrane fouling characteristic. Also membrane resistance test and the component of foulant was analyzed to investigate what is specific foulant in the MBR.

• 한국방재학회:학술대회논문집
• /
• 2010.02a
• /
• pp.101.1-101.1
• /
• 2010

빗물과 생활하수를 이용하여 재이용수로 활용하는 방법은 각각 연구가 되어 있다. 하지만 그 두가지를 합쳐서 사용하는 연구는 현재까지 미흡하며, 본 연구에서 사용된 기술(Hybrid-MBR, 이하 HMBR)을 활용해서 중수 수질기준에 맞도록 Blending하는 실험을 하였다. 고도처리를 할 경우 운전이나 장치상의 문제로 수질오염이 생길 수 있는 것을 본 실험해서 사용한 blending을 이용하여 수질 오염을 방재할 수 있다.

• Membrane Journal
• /
• v.16 no.3
• /
• pp.182-187
• /
• 2006

The purpose of this study was to investigate effect of coagulation on filtration performance of membrane in submerged MBR system and influence of continuous aeration to reduce fouling of membrane surface on coagulated floc. For this purpose, aeration tank sludge of MBR system was compared with jar-test sludge. The experimental results were analysed in terms of floc size and SRF (Specific resistance of Filtration). The more alum was added, the more content of floc below $10{\mu}m$ reduced and SRF decreased. But compared with jar-test results, it was found that effect of coagulation on MBR floc was reduced. Operation time of membrane in alum added MBR was longer than that in control MBR. But operation time was not proportional to alum dose. It was thought that the result was reason that floc below $10{\mu}m$ was not reduced sufficiently by shear force of continuous aeration. Moreover it was founded that if alum is added more than proper dose, it brings filtration resistance to increase.