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Membrane fouling is a process whereby a solution or a particle is deposited on a membrane surface or in membrane pores in a process such as in a Membrane bioreactor, so that the membrane's performance is degraded. It is a major obstacle to the widespread use of this technology. Membrane fouling can cause severe flux decline and affect the quality of the water produced. Severe fouling may require intense chemical cleaning or membrane replacement. This increases the operating costs of a treatment plant. There are various types of foulants: colloidal (clays, flocs), biological (bacteria, fungi), organic (oils, polyelectrolytes, humics) and scaling (mineral precipitates).〔Baker, R.W. (2004). Membrane Technology and Applications, England: John Wiley & Sons Ltd〕 Fouling can be divided into reversible and irreversible fouling based on the attachment strength of particles to the membrane surface. Reversible fouling can be removed by a strong shear force or backwashing. Formation of a strong matrix of fouling layer with the solute during a continuous filtration process will result in reversible fouling being transformed into an irreversible fouling layer. Irreversible fouling is the strong attachment of particles which cannot be removed by physical cleaning.〔Choi, H., Zhang, K., Dionysiou, D.D.,Oerther, D.B.& Sorial, G.A. (2005) Effect of permeate flux and tangential flow on membrane fouling for wastewater treatment. J. Separation and Purification Technology 45: 68-78. 〕 == Influential factors == Factors that affect membrane fouling: Recent fundamental studies indicate that membrane fouling is influenced by numerous factors such as system hydrodynamics, operating conditions, membrane properties, and material property (solute). At low pressure, low feed concentration, and high feed velocity, concentration polarisation effects are minimal and flux is almost proportional to trans-membrane pressure difference. However, in the high pressure range, flux becomes almost independent of applied pressure.〔Ghosh, R., 2006, Principles of Bioseparation Engineering, World Scientific Publishing Pvt Ltd.〕 Deviation from linear flux-pressure relation is due to concentration polarisation. At low feed flow rate or with high feed concentration, the limiting flux situation is observed even at relatively low pressures. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Membrane fouling」の詳細全文を読む スポンサード リンク
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