Reduction of membrane fouling by innovative method (injection of air jet)
Tóm tắt
One of the most important challenges about the Membrane Bio Reactors is membrane fouling. Fouling has been at the centre of a globe debate for more recent years. It leads to high operational and maintenance costs such as membrane damage and replacement of membrane. Membrane fouling is attributed to the physicochemical interactions between the bio fluid and membrane. In order to decrease the fouling in bioreactors there are common anti fouling strategies such as operation at low flux, Optimization of aeration flow-rate and Physical and chemical cleanings. However, often they are not effective. This work deal with fouling crisis by a new and innovative method in order to reduce of fouling on membrane surface by injection of parallel air jet on membrane bio reactor. This is a new idea and fundamental study about the influence of wall jet on fouling of membrane surface. This study is included both experimental and numerical investigations. In order to polarize the stream path on the surface of the membrane, four symmetric nozzles were implemented at the bottom of the membrane surface upon the sparger. The changes in the fouling resistance were experimentally measured at five various jet velocities and all of them recorded by a computer system. In addition the effect of air jet velocity and shear stress on fouling resistances was also investigated by computational fluid dynamics at the similar conditions. It was revealed that the permeate flux and resistance of fouling can be related to shear stress of air flow at the membrane surface. When the velocity of air jets increase, the permeate flux increase too. Also, results illustrate that jet injection can partially remove the cake which was formed on the surface of the membrane. Correlations were developed for estimating each resistance of the membrane surface via the shear stress. The resistances of the cake are removed by the jet velocity changes, from 20% in lower jet velocity up to 40% in higher jet velocity.
Tài liệu tham khảo
Merchuk JC, Contreras A, Garcia F, Molina Grima E: Studies of mixing in a concentric tube airlift bioreactor with different spargers. Chem Eng Sci 1998, 53: 709–719. 10.1016/S0009-2509(97)00340-0
Lu Y, Ding Z, Liu L, Wang Z, Ma R: The influence of bubble characteristics on the performance of submerged fiber membrane module used in microfiltration. Sep Purif Technol 2008, 61: 89–95. 10.1016/j.seppur.2007.09.019
Taha T, Cheong WL, Field RW, Cui ZF: Gas-sparged ultrafiltration using horizontal and inclined tubular membranes - a CFD study. J Membr Sci 2006, 279: 487–494. 10.1016/j.memsci.2005.12.063
Pak A, Mohammadi T, Hosseinalipour SM, Allahdini V: CFD modeling of porous membranes. Desalination 2008, 222: 482–488. 10.1016/j.desal.2007.01.152
Martinelli L: Influence de l'aération sur le Colmatage des membranes immerges. PhD thesis at Université Libre de Bruxelles. INSA Toulouse, Institut National des Sciences Appliquées; 2006
Xu Z, Yu J: Hydrodynamics and mass transfer in a novel multi-airlifting membrane bioreactor. Chem Eng Sci 2008, 63: 1941–1949. 10.1016/j.ces.2007.12.026
Nguyen Cong Duc E, Fournier L, Levecq L, Lesjean B, Grelier P, Tazi-Pain A: Local hydrodynamic investigation of the aeration in a submerged hollow fiber membranes cassette. J Membr Sci 2008, 321(2):264–271. 10.1016/j.memsci.2008.05.001
Lee WT, Kang ST, Shin HS: Sludge characteristics and their contribution to microfiltration in submerged membrane bioreactors. J Membr Sci 2003, 216: 217–227. 10.1016/S0376-7388(03)00073-5
Ducom G, Puech FP, Cabassud C: Air sparging with flat sheet nanofiltration: a link between wall shear stresses and flux enhancement. Desalination 2002, 145: 97–102. 10.1016/S0011-9164(02)00392-2
Cui ZF, Chang S, Fane AG: The use of gas bubbling to enhance membrane process. J Membr Sci 2003, 221: 1–35. 10.1016/S0376-7388(03)00246-1
Hong SP, Bae TH, Tak TM, Hong S, Randall A: Fouling control in activated sludge submerged hollow-fiber membrane bioreactor. Desalination 2002, 143: 219–228. 10.1016/S0011-9164(02)00260-6
Sofia A, Ng WJ, Ong SL: Engineering design approaches for minimum fouling in submerged MBR. Desalination 2004, 160: 67–74. 10.1016/S0011-9164(04)90018-5
Wicaksana F, Fane AG, Chen V: Fiber movement induced by bubbling using submerged hollow-fiber membranes. J Membr Sci 2006, 271: 186–195. 10.1016/j.memsci.2005.07.024
Pollet S, Guigui C, Cabassud C: Fouling and its reversibility in relation to flow properties and module design in aerated hollow fiber modules for membrane bioreactors. Water Sci Technol 2008, 57: 629–636. 10.2166/wst.2008.113
Ndinisa NV, Fane AG, Wiley DE, Fletcher DF: Fouling control in a submerged flat sheet membrane system. Part II. Two-phase flow characterization and CFD simulations. Sep Sci Technol 2005, 41(7):1411–1445. 10.1080/01496390600633915
Cui ZF, Wright KIT: Gas–liquid two-phase cross-flow ultrafiltration of BSA and dextran solutions. J Membr Sci 1994, 90: 183–189. 10.1016/0376-7388(94)80045-6
Lee CK, Chang WG, Ju YH: Air slugs entrapped cross-flow filtration of bacterial suspensions. Biotechnol Bioeng 1993, 41: 525–530. 10.1002/bit.260410504
Mercier-Bonin M, Lagane C, Fonade C: Influence of a gas/liquid two-phase flow on the ultrafiltration and microfiltration performances, case of a ceramic flat sheet membrane. J Membr Sci 2000, 180: 93–102. 10.1016/S0376-7388(00)00520-2
Cabassud C, Laborie S, Durand-Bourlier L, Laine JM: Air sparging in ultrafiltration hollow fibers: relationship between flux enhancement, cake characteristics and hydrodynamic parameters. J Membr Sci 2001, 181: 57–69. 10.1016/S0376-7388(00)00538-X
Bellara SR, Cui ZF, Pepper DS: Gas sparging to enhance permeate flux in ultrafiltration using hollow fibre membranes. J Membr Sci 1996, 121: 175–184. 10.1016/S0376-7388(96)00173-1
Ducom G, Puech FP, Cabassud C: Gas/liquid two phase flow in a flat sheet filtration module: measurement of local wall shear stresses. J Chem Eng 2003, 81(3–4):771–775.
Khalili-Garakani AH, Mehrnia MR, Mostoufi N, Sarrafzadeh MH: Analyze and control fouling in an airlift membrane bioreactor: CFD simulation and experimental studies. Process Biochem 2011, 46: 1138–1145. 10.1016/j.procbio.2011.01.036
Stern F, Wilson RV, Coleman HW, Paterson EG: Comprehensive approach to verification and validation of CFD simulations—part 1: methodology and procedures. J Fluids Eng 2001, 123: 793–802. 10.1115/1.1412235
Tagemman R, Gretler W: Numerical simulation of a two-dimensional turbulent wall jet in an external stream. Forsch Ingenieurwes 2000, 66: 31–39. 10.1007/s100100000039
Schlichting H, Gersten K: Boundary Layer Theory. Springer, Heidelberg; 2003.
Constantinides A, Mostoufi N: Numerical Methods for Chemical Engineering With MATLAB Applications. Prentice Hall, New Jersey; 1999.