• Journal of Korean Society of Environmental Engineers
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• v.38 no.6
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• pp.323-328
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• 2016

Pressurized membrane used for side-stream MBR process requires fouling control strategy both for normal and abnormal operation conditions for stable operation of the facilities. In this study, $85m^3/day$ of pilot-scale side-stream MBR process was constructed for the evaluation of fouling mitigation by air bubble injection into the membrane module. In addition, fouling phenomena at abnormal operation conditions of low influent and/or loading rate were also investigated. Injection of air bubble was found to be effective in delaying transmembrane pressure (TMP) increase mainly due to scouring effect on the membrane surface, resulting in expanded filtration cycle at a high flux of $40L/m^2{\cdot}h$ (LMH). At abnormal operation condition, injection of PACl (53 mg/L as Al) into the bioreactor showed 19% reduction of TMP increase. However, inhibition of nitrifying bacteria by continuous PACl injection was observed from batch experiments. In contrast, injection of powdered activated carbon (PAC, 0.6 g/L) was able to maintain the initial TMP of $0.2kg/cm^2$ for 5 days at the abnormal conditions. It may have been caused from the adsorption of extracellular polymeric substances (EPS), which was known to be excessively released during growth inhibition condition and act as the major foulants in MBR operations.

• 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 Journal
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• v.16 no.3
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• pp.213-220
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• 2006

Microfiltration and Nanofiltration membrane were prepared and properties of the membrane system were studied for the application of desaltingfrefiningiconcentrating process of dye production. The membrane system improved the quality of dye produce and productivity was enhanced due to reduction of processing steps and material cost. Membrane and pressure type membrane element in various dye concentration for using desaltingirefiningiconcentrating of dye processing were investigated.

• Membrane Journal
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• v.27 no.4
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• pp.367-373
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• 2017

Pressurized membrane module systems, including hollow fiber type of Microfiltration (MF) and Ultrafiltration (UF) membranes are being increasingly used in drinking water treatment due to their high removal efficiency of pathogen. However, when fibers are damaged in pressurized membrane system, the pathogen will be able to penetrate the membrane. Therefore, it is essential to guarantee the regulatory requirements for water quality by an effective on-line or off-line condition integrity monitoring methods. Recently, pressure decay test (PDT) which is one of membrane integrity tests has been reflected to drinking water treatment plants using pressurized membrane module. In this paper, three different method were used to perform PDT and three different sensitivity values were analyzed through experiments. Three types of direct integrity test methods were applied to pressure feed side, filtrate side and bidirectional pressure decay test. The results of these experiments show that the sensitivity was increasing when the volume of pressurized gas was decreasing. The sensitivity is inversely proportional to the gas volume. Furthermore, it is desirable to increase pressure difference between feed side and permeate side in order to achieve higher sensitivity in the PDT by membrane damage.

• Membrane Journal
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• v.30 no.2
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• pp.131-137
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• 2020

In this study, effect of inorganic particles on organic fouling was investigated by a laboratory-scaled pressurized membrane filtration. In order to cause organic fouling, sodium alginate (SA) was used as a feed solution. Regardless of the presence of inorganic SiO₂ particles, the complete pore blocking played an important role in determining the fouling rate during the initial period of membrane filtration. However, the formation of cake layer resulted in the membrane fouling more dominantly as filtration time progressed. In the presence of inorganic particles, both specific cake resistance and compressibility associated with the membrane fouling formed were relatively lower than that without SiO₂ particles. Membrane fouling was more severe at constant flux mode of filtration than that observed at constant pressure mode probably due to the concomitant increase of compressibility of fouling layer with transmembrane pressure (TMP). It was found that the presence of SA and SiO₂ particles in feed solution provided the synergistic effect on the hydraulic backwashing to reduce membrane fouling as compared to the SA solution alone without the inorganic particles.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.335-341
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• 2016

Various studies have forwarded an outstanding wastewater effluent treatment systems toward securing sustainable supply of water sources. In this paper, a broad overview of the performance of MF membrane as pretreatment option for wastewater reuse will be presented based on the literature survey and experiments conducted over the wastewater reuse pilot plant. The pilot plant was operated with a continuous data acquisition for about 300days under various chemical enhanced backwash (CEB) system with subsequent treated water quality analysis. Accordingly, assessment of the effluent revealed that the pretreated water is suitable enough to be used as an input for Reverse Osmosis (RO) unit and significant effect of CEB and concentration of NaOCl is also conceived from the analysis. Moreover, it's also observed that the application of various CEB condition over long operational hours induced a constant declination of overall performance of MF membrane.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.21-24
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• 2012

In this study, Anaerobic Membrane Bioreactor(AnMBR) treating food waste leachate was operated to investigate treatment efficiency of anaerobic process, operational parameters and production of biogas. AnMBR was operated under the condition of filtration type of inside-out mode. AnMBR was operated under the condition that range of permeate flux was from 15 to 20 LMH and range of transmembrane pressure was from 1 to $3 kgf/cm^2$. It was not good that AnMBR was performed under direct connection between anaerobic reactor and external UF module. so, this connection method changed to indirect connection using buffer tank was placed between anaerobic reactor and UF external module. TCOD and SCOD values were that influent were about 113 g/L, 62 g/L and effluent were 25 g/L, 12 g/L, respectively. also TCOD and SCOD removal efficiency were 77% and 81%, respectively. but after added UF process, COD and SCOD removal efficiency was increased to 93% and 86%, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.50-50
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• 2022

한국농어촌공사 산하의 농업용저수지 중 3786개소에 대한 수질조사를 '19년도에 실시한 결과, TOC 기준 4등급 초과 저수지 비율은 약 20%로써, 도심 근교 저수지에서 녹조현상 빈발로 인해 수질, 악취, 미관 등의 환경문제 개선 민원이 다수 발생하고 있다. 현재 녹조 발생 사후관리를 위해 주로 사용되고 있는 대형 조류제거선은 저수심 수변부에서의 적용성에 한계가 있고, Al 기반의 응집제를 사용하여 조류를 수거해서 폐기하고 있는 실정이다. (주)이엔이티는 농어촌연구원, (주)코레드, (주)삼호인넷과 함께 호소나 정체하천의 수변지역에 적용될 수 있는 저에너지형 유해조류 포집시스템 개발과, 수거된 조류부산물을 무독화하여 농업재료로 재활용하는 방안을 연구하고 있다. 저수지나 정체수역의 녹조는 바람, 수면유동 등에 의해 수변에 집적되는 특성이 있어, 인공지능 기술로 녹조현상을 감시하여 조류 밀집구간에 접근할 수 있는 자율이동식 수상이동장치를 개발 중이다. 수상이동장치는 조류포집장치를 탑재하기 위한 부력체, 원격 운전이 가능한 무인항법장치, 수변식생대 및 저수심지역 이동을 고려한 수차방식 추진체, 전체 장치의 전원 공급을 위한 고성능 배터리 등으로 구성하여 상세 도면 설계를 진행하고 있다. 조류포집장치에는 표층에 주로 분포하는 남조류를 선택 흡입하는 포집 부표를 적용하였고, Al계 응집제 사용을 배제한 분리막 실험을 통해 침지형 막분리조 및 가압형 농축조를 설계하였다. 유해조류 포집 및 농축은 수상에서 이동체에 탑재하여 이뤄지고, 육상에서는 자원 회수가 가능하도록 회분식 응집공정으로 구분하였다. 조류 밀집지역에서 수거된 조류의 무독화 및 농업재료 자원화 타당성 평가를 위해 특용 버섯균주를 활용한 시료별 분석항목을 선정하고 실험 매트릭스에 따라 실증실험을 수행하였다. 수거조류를 전처리하여 성분 및 발열량을 분석하고 버섯재배 전후의 마이크로시스틴 독소(LR, RR, LR)를 포함한 성분 분석을 수행하여, 고체연료, 비료 및 사료로 활용방안을 검토하였다. 무인자율이동 조류포집장치는 실증화 규모로 제작하여 기선정된 테스트베드에서 현장적용성 평가를 수행할 예정이다. 본 연구를 통해 개발된 유해조류 포집 시스템은 기존의 녹조제거 방안을 보완하여 정체수역의 생태계 복원 및 친수공간의 환경개선 등에 적용되며, 무독화가 입증된 유해조류의 농업재료 자원화 기술은 고부가 상품 개발 및 환경폐기물 감축에 활용될 것이다.