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Fouling layer formation by flocs in inside-out driven capillary ultrafiltration membranes
The interest in low pressure membrane filtration, i. e. micro- and ultrafiltration (MF and UF) increased rapidly in recent years, particularly due to the extremely high requirements for potable water quality with respect to hygiene aspects. However, some limiting factors exist, especially when applying MF or UF for the direct treatment of surface waters without any pretreatment. Particularly dissolved organic matter (DOM) can be very problematic due to the formation of hardly reversible and/or irreversible fouling layers and due to its general contribution in formation of disinfection by-products (DBP). To get these problems under control, different pretreatment processes are conceivable and available, whereas this work is focused on the hybrid process coagulation and UF. Coagulation is an established technology for the removal of DOM and, from an engineering perspective, can easily be combined with membrane processes. To achieve an appropriate operation performance of hybrid process with respect to economic and procedural engineering aspects, it is necessary to understand what the limiting factors are, when they are of importance and how their effects may be avoided by design and the chosen operating parameters. The most important point in this respect is to understand how fouling layers are formed, because these layers will limit the efficiency of the entire process. Therefore, the objective of this work was to contribute to the understanding of formation of fouling layers by porous floc aggregates during filtration of coagulated raw waters in inside-out driven capillary UF membranes. A computational fluid dynamics (CFD) model was developed for the description of the complete fluid flow field in inside-out driven UF capillaries of arbitrary cylindrical geometry, alignment and physical properties of the membrane and chosen operation condition. This was done by numerical calculations of the Navier-Stokes and continuity equations. Based on the fluid flow field, floc velocities and trajectories were derived by ...
Fouling layer formation by flocs in inside-out driven capillary ultrafiltration membranes
The interest in low pressure membrane filtration, i. e. micro- and ultrafiltration (MF and UF) increased rapidly in recent years, particularly due to the extremely high requirements for potable water quality with respect to hygiene aspects. However, some limiting factors exist, especially when applying MF or UF for the direct treatment of surface waters without any pretreatment. Particularly dissolved organic matter (DOM) can be very problematic due to the formation of hardly reversible and/or irreversible fouling layers and due to its general contribution in formation of disinfection by-products (DBP). To get these problems under control, different pretreatment processes are conceivable and available, whereas this work is focused on the hybrid process coagulation and UF. Coagulation is an established technology for the removal of DOM and, from an engineering perspective, can easily be combined with membrane processes. To achieve an appropriate operation performance of hybrid process with respect to economic and procedural engineering aspects, it is necessary to understand what the limiting factors are, when they are of importance and how their effects may be avoided by design and the chosen operating parameters. The most important point in this respect is to understand how fouling layers are formed, because these layers will limit the efficiency of the entire process. Therefore, the objective of this work was to contribute to the understanding of formation of fouling layers by porous floc aggregates during filtration of coagulated raw waters in inside-out driven capillary UF membranes. A computational fluid dynamics (CFD) model was developed for the description of the complete fluid flow field in inside-out driven UF capillaries of arbitrary cylindrical geometry, alignment and physical properties of the membrane and chosen operation condition. This was done by numerical calculations of the Navier-Stokes and continuity equations. Based on the fluid flow field, floc velocities and trajectories were derived by ...
Fouling layer formation by flocs in inside-out driven capillary ultrafiltration membranes
Lerch, André (author) / Gimbel, Rolf
2008-05-05
Theses
Electronic Resource
English
Fouling - Organic matter fouling of ultrafiltration membranes
| Online Contents | 2003
Organic matter fouling of ultrafiltration membranes
| British Library Conference Proceedings | 2003