MBR공정에 있어서 수리학적 거동이 막여과에 미치는 영향

이형옥 ( Hyeong-ok Lee ),정훈섭 ( Hun-seob Jung ),현길수 ( Kil-soo Hyun ) 한국수처리학회(구 한국수처리기술연구회) 2017 한국수처리학회지 Vol.25 No.5

Stirred dead-cell filtration has been widely used for fundamental studies on membrane fouling caused by soluble and colloidal matter during membrane filtration. In this study, the performance of MBR using a dead-end stirrer cell was conducted to investigate the removal of dissolved organic matters from real mixed liquor in aeration tank and transmembrane pressure (TMP) with hydraulic behavior on the membrane surface. Applied stirring rate as a hydraulic behavior index ranged from 100 to 1000 rpm. Influent water qualities were in the range of MLSS < 10,000 mg/L, UV₂₅₄ < 0.3 cm^-1, dissolved organic carbon (DOC) < 45 mg/L, and specific UV absorbance (SUVA) <2.5 L/mg.m, respectively. As a result, the membrane biofiltration achieved higher efficiencies of TOC and DOC except UV₂₅₄ having lower efficiency < 40% regardless of the hydraulic shear force. An increase in the hydraulic shear force resulted in a decline in TMP. This indicates that higher hydraulic shear force is needed to improve TMP in operating a long-term filtration of MBR having a suitable permeate flux to enhance dissolved organic matter removal efficiency.

초고속국가망의 제도적ㆍ관리적 보안대책 방안

이형옥(Hyeong Ok Lee) 한국정보보호학회 2001 情報保護學會誌 Vol.11 No.1

MBR공정의 운전 방식이 막여과에 미치는 영향

이형옥 ( Hyeong-ok Lee ),현길수 ( Kil-soo Hyun ) 한국수처리학회 2017 한국수처리학회지 Vol.25 No.3

Membrane fouling is complicated with physicochemical interactions among membrane bioreactor (MBR) components of membrane and module configuration, system operation and various mixed liquor components. In this study, the performances of MBR using stirred dead end filtration cell on pollutants removal with filtration modes in wastewater. Batch tests were carried out with real wastewater taken from the aeration tank of real activated sludge process. Influent concentrations were in the range of COD 30-103mg/L, MLSS <10,000mg/L, UV₂₅₄ <0.3cm^-1, and dissolved organic carbon (DOC) <45 mg/L. Applied membrane permeate flux was < 20 L/m².h. As a result, MBR process achieved the high removal for COD, T-P and DOC with removal efficiencies of >90%, 70%, and 70% while it achieved a relative low removal for T-N with removal efficiencies of 50%. Longer filtration time increased TMP by accelerating membrane fouling due to the deposit of particulates on the surface of the membrane as well as the increase of total filtration resistance.

혐기,호기활성슬러지GAC시스템과 연계한 막여과 처리 특성

이형옥 ( Hyeong Ok Lee ),김지연 ( Ji Yeon Kim ),현길수 ( Kil Soo Hyun ) 한국수처리학회 2012 한국수처리학회지 Vol.20 No.1

The objective of this study was to investigate the charateristics of flux. transmembrane pressure (TMP), and substrate reduction for biological wastewater treatment processes coupled with menbrane filteration (MF) and to evaluate the comparative performance of aerobic process/MF. anaerobic-aerobic (ANO) process/MF, and ANO-granular activated carbon (GAC) filter/MF processes on the reclamation and reuse of wastewater. The characteristics of real wastewater used for this study was: COD 5.5-14.8 mg/l. SS 0.3-16.0mg/l, T -N 3.647-13.415mg/l. T -P 0.114-3.217mg/L. As a result. the flux of the MF decreased rapidly within about 2 min of filtration time regardless of TMP and the water qualities treated by the processes. This initial low flux resulted in the clogging of the membrane pore due to particular and organic matters in the effluent from the processes. The substrate removal rate of the MF process increased with decreasing TMP regardless of pollutants. The above results showed that the optimum TMP was 0.4 bar for the processes. The results suggest that the GAC bed after the ANO process is needed to decrease TMP and to obtain the reuse water with a good quality.

하수의 재이용을 위한 혐기-호기 활성슬러지 및 입상슬러지공정과막여과 공정의 연계처리특성 비교

이형옥 ( Hyeong Ok Lee ),김지연 ( Ji Yeon Kim ),서석환 ( Seok Hwan Seo ),김태우 ( Tae Woo Kim ),현길수 ( Kil Soo Hyun ) 한국수처리학회 2015 한국수처리학회지 Vol.23 No.2

The study was conducted to compare and evaluate the treatment characteristics of anaerobic-aerobic activated sludge process (A2O) with GAC bed (A2O+GAC) and granular sludge sequencing batch reactor (GS-SBR) processes coupled with membrane filtration (MF) process for wastewater reuse. Influent was used real wastewater for A2O+GAC and synthetic wastewater for GS processes. As a result, the GS-SBR+MF system with HRT 4 hr was very effective in reducing particulate matter as well as organic and nutrient removal. Despite influent with high concentration of COD 300 gm/L, the efficiency of GS-SBR+MF system was similar to that of A2O+GAC+MF with HRT 8 hr and the influent of COD <110mg/L. Transmembrane pressure (TMP) of MF process increased in proportion to the increase of filtration velocity of MF, whereas the efficiency of MF on particulate matter removal slightly decreased with the increase of filtration velocity of MFP due to an improper formation of cake layer on membrane surface. Effluent qualities from both system were adequate for water reuse.

MBR공정의 혼합액 슬러지 성분에 따른 기질저감과 막오염특성

이형옥 ( Hyeong-ok Lee ),현길수 ( Kil-soo Hyun ) 한국수처리학회(구 한국수처리기술연구회) 2020 한국수처리학회지 Vol.28 No.2

This study aims to investigate the effects of sludge components and agitation rate on contaminant removal, membrane filtration, and fouling in a membrane bioreactor (MBR) by using a dead-end stirrer cell. The real mixed liquor used for this study was pretreated to segregate three sludge components, namely activated sludge (AS), suspended solids (SS), and supernatant (SUP) including colloids and solutes. In reducing the contaminants, MBR filtration of AS and SS at agitation rates of 0 - 1000 rpm achieved higher efficiencies (20-30%) than those of achieved SUP filtration. In particular, the removal efficiencies of COD and T-P by the MBR were about three times higher than that of T-N. In reducing total organic carbon (TOC) and dissolved organic carbon (DOC), the MBR filtration of AS and SS achieved 1.7 times higher efficiency than that of SUP, whereas the MBR filtration of SUP in reducing ultraviolet at 254nm (UV₂₅₄) achieved 1.4 and 4.7 times higher efficiencies, respectively than those of AS and SS. On the other hand, the profiles of TMP build-up within 30 min of filtration time were larger, corresponding to AS > SS > SUP. This reveals that the solid level in developing TMP has a greater effects than dissolved level in mixed liquor. This result also indicates that both membrane filtration to lower TMP and an appropriate agitation rate (< 400rpm) are required to minimize membrane fouling by creating a shear force near the membrane surface, in order to prevent both micro-flocs generation and cake layer formation.

Folded 하이퍼-스타 그래프의 병렬 경로

이형옥,최정,박승배,조정호,임형석,Lee, Hyeong-Ok,Choi, Jung,Park, Seung-Bae,Cho, Chung-Ho,Lim, Hyeong-Seok 한국정보처리학회 1999 정보처리논문지 Vol.6 No.7

상호 연결 망에서 병렬 경로는 전송할 메시지를 패킷으로 분할하여 여러 개의 경로를 통하여 동시에 전송할 수 있어서 메시지 전송 시간을 줄일 수 있으며, 라우팅 경로상의 노트나 에지가 고장이 발생했을 때 메시지 전송을 위한 대체 경로를 설정할 수 있으므로 중요한 의미를 갖는다. 2n개의 이진수로 노드를 표현하는 Folded 하이퍼-스타 그래프 FHS(2n,n)은 하이퍼-큐브와 그의 변형된 그래프보다 망 비용이 개선된 상호 연결 망이다. 본 논문에서는 병렬 컴퓨터의 위상으로 제안된 Folded 하이퍼-스타 그래프 FHS(2n,n)에서 노드 중복하지 않는 병렬 경로를 분석하고, 그 결과를 이용하여 Folded 하이퍼-스타 그래프 FHS(2n,n)의 고장 지름이 2n-1임을 분석한다. Parallel paths in an interconnection network have some significance in that message transmission time can be reduced because message is divided into packets and transmitted in parallel through several paths, and also an whose nodes has 2n binary bit string, is an interconnection network which has a lower network cost than hypercube and its variation. In this paper, we analyze node disjoint parallel path in Folded Hyper-Star graph FHS(2n,n) proposed as the topology of parallel computers and, using the result, prove that the fault diameter of a Folded Hyper-Star graph FHS(2n,n) is 2n-1.

포스터 : 하이퍼-토러스와 피터슨-토러스 네트워크 사이의 사상 알고리즘

이형옥 ( Hyeong Ok Lee ),김종석 ( Jong Seok Kim ) 한국컴퓨터교육학회 2012 한국컴퓨터교육학회 학술발표대회논문집 Vol.16 No.2

최근에 3차원 하이퍼큐브와 피터슨 그래프를 기본모듈로 하고, 분지수가 4로 고정된 하이퍼-토러스(QT) 연결망과 피터슨-토러스(PT) 연결망이 제안되었다. 하이퍼-토러스(QT) 연결망과 피터슨-토러스(PT) 연결망은 기존에 발표된 노드 개수가 비슷한 메쉬 부류 연결망보다 망비용이 우수한 연결망들이다. 본 논문에서는 하이퍼-토러스 QT(n,n) 연결망을 피터슨-토러스 PT(n,n) 연결망에 사상하는 알고리즘을 제안한다. QT(n,n)이 PT(n,n)에 연장율 2, 밀집율 3으로 임베딩 가능함을 보이고, QT(n,n)은 PT(n,n)에 평균 연장율 2 이하에 임베딩 가능함을 보인다.

행렬- 스타 그래프: 행렬 연산에 기반한 새로운 상호 연결망

이형옥(Hyeong Ok Lee),임형석(Hyeong Seok Lim) 한국정보과학회 1999 정보과학회논문지 : 시스템 및 이론 Vol.26 No.4

본 논문에서는 상호 연결망의 노드를 행렬로 표현하고 행렬 연산을 이용하여 에지를 정의한 새로운 상호 연결망으로 행렬-스타 그래프를 제안한다. 행렬-스타 그래프는 널리 알려진 스타 그래프를 일반화한 그래프이다. 먼저, 행렬-스타 그래프의 노드를 2×n 행렬로 표현한 행렬-스타 그래프 MS_(2,n)에 대하여 주요 망 척도인 분지수, 연결도, 확장성, 대칭성, 라우팅, 지름, 방송 등을 분석한다. 다음으로, 행렬-스타 그래프 MS_(2,n)의 노드를 2차원과 3차원으로 일반화한 행렬-스타 그래프 MS_(k,n)과 MS_(k,n,p)를 정의하고, 행렬-스타 그래프 MS_(k,n,p)의 라우팅 알고리즘과 지름을 분석한다. 상호 연결망의 중요 망 척도중 하나는 망 비용이고, 상호 연결망의 망 비용은 그 연결망의 분지수와 지름의 곱으로 정의된다. star 그래프는 다른 상호 연결망 보다 작은 망 비용을 갖는다. 최근에 제안된 Macro-Star 그래프는 star 그래프에 비해 상대적으로 망 비용이 작은 값을 갖는 연결망이다. (n²)!개의 노드를 갖는 행렬-스타 그래프 MS_(k,k,k)(k=³√n²)와 ((n-1)²+1)!개의 노드를 갖는 Macro-Star 그래프 MS(n-1,n-1)의 망 비용은 행렬-스타 그래프 MS_(k,k,k)(k=³√n²)는 O(n^(27))이고, Macro-Star 그래프 MS(n-1,n- 1)은 O(n³)이다. 이는 행렬-스타 그래프가 스타 그래프와 Macro-Star 그래프 보다 망 비용이 우수함을 의미한다. In this paper, we propose a matrix-star graph, which represents a node as a matrix and defines edges using the matrix operations, as a new interconnection network. The matrix-star graph is a generalization of the well-known star graph, First, we analyze the characteristics of a matrix-star graph MS_(2,n) in which each nodes is a 2×n matrix, in terms of the network parameters such as degree, connectivity, scalability, symmetry, routing, diameter, and broadcasting. Next, we propose a matrix-star graph MS_(k,n) and MS_(k,n,p) generalizing the nodes of MS_(2,n) to 2-dimensional and 3-dimensional matrices respectively. And, we analyze the routing algorithm and the diameter of a matrix-star graph MS_(k,n,p). One of the important interconnection network measures is the network cost. The network cost of an interconnection network is defined as the product of the degree and the diameter of the network. The star graph has lower network cost than other interconnection networks. The recently proposed Macro-Star graph has a relatively lower network cost than that of the star graph. A matrix-star graph MS_(k,k,k)(k=³√n²) and a Macro-Star graph MS(n-1,n-1) have (n²)! and ((n-1)²+1)! nodes, respectively and the network costs of MS_(k,k,k) and MS(n-1,n-1) are O(n^(2.7)) and O(n³), respectively, It means that a matrix-star graph is better than a star graph and a Macro-Star graph in terms of the network cost.

매크로-스타 그래프와 행렬 스타 그래프 사이의 임베딩

이형옥(Lee Hyeong Ok) 한국정보처리학회 1999 정보처리학회논문지 Vol.6 No.3

A Macro-Star graph which has a star graph as a basic module has node symmetry, maximum fault tolerance, and hierarchical decomposition property. And, it is an interconnection network which improves a network cost against a star graph. a matrix star graph also has such good properties of a Macro-Star graph and is an interconnection network which has a lower network cost than a Macro-Star graph. In this paper, we propose a method to embed between a Macro-Star graph and a matrix star graph. We show that a Macro-Star graph MS(k,n) can be embedded into a matrix star graph MSk,n 1 with dilation 2. In addition, we show that a matrix star graph MSk,n can be embedded into a Macro-Star graph MS(k,n 1) with dilation 4 and average dilation 3 or less as well. This result means that several algorithms developed in a star graph can be simulated in a matrix star graph with constant cost.