Methods for improving filtration performance of hollow fiber membranes
First Claim
1. A method for improving performance of a filtration membrane module comprising a plurality of microporous hollow fibers, said method comprising subjecting said module to gas-assisted backwashing,wherein said gas-assisted backwashing comprises subjecting said fibers to:
- a) optional forward flushing,b) bottom backwashing,c) top backwashing,d) soaking, ande) rinsing, andfurther subjecting said fibers, at least once, before one or more of a), b), c), d) or e), to sufficient gas pressure on the lumen side thereof to provide fiber expansion without displacing water from the hollow fiber membrane pores, and to drain the liquid from the fibers by driving the fluid through the fibers,wherein said gas-assisted backwashing removes fouling components from said fibers, thereby improving performance of said filtration membrane module.
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Abstract
In accordance with the present invention, there are provided methods for improving performance of hollow fiber filtration membrane modules. Invention methods comprise a unique backwashing technique wherein the hollow fiber membranes within the module are pressurized with a gas on the feed side at specified times during the backwash. Periodic use of invention methods effectively removes fouling components from the hollow-fiber membranes, thereby providing stable permeability and low trans-membrane pressures, which results in an efficient and economic filtration process. In addition, there are provided methods for cleaning hollow fiber membranes and increasing filtrate flow rate through membranes.
96 Citations
33 Claims
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1. A method for improving performance of a filtration membrane module comprising a plurality of microporous hollow fibers, said method comprising subjecting said module to gas-assisted backwashing,
wherein said gas-assisted backwashing comprises subjecting said fibers to: -
a) optional forward flushing, b) bottom backwashing, c) top backwashing, d) soaking, and e) rinsing, and further subjecting said fibers, at least once, before one or more of a), b), c), d) or e), to sufficient gas pressure on the lumen side thereof to provide fiber expansion without displacing water from the hollow fiber membrane pores, and to drain the liquid from the fibers by driving the fluid through the fibers, wherein said gas-assisted backwashing removes fouling components from said fibers, thereby improving performance of said filtration membrane module. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method for cleaning a hollow fiber membrane, said method comprising subjecting said membrane to gas-assisted backwash, wherein said gas-assisted backwash comprises:
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a) optional forward flushing, b) bottom backwashing, c) top backwashing, d) soaking, and e) rinsing, and further subjecting said hollow fiber membrane, at least once, before one or more of a), b), c), d) or e), to sufficient gas pressure on the lumen side thereof to provide expansion of said hollow fiber membrane without displacing water from the hollow fiber membrane pores, and to drain the liquid from said hollow fiber membrane by driving the fluid through the membrane.
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33. A method for increasing filtrate flow rate through a membrane, said method comprising subjecting said membrane to a gas-assisted backwash, wherein said gas-assisted backwash comprises;
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a) optional forward flushing, b) bottom backwashing, c) top backwashing, d) soaking, and e) rinsing, and further subjecting said membrane, at least once, before one or more of a), b), c), d) or e), to sufficient gas pressure on the lumen side thereof to provide fiber expansion of said membrane without displacing water from the hollow fiber membrane pores, and to drain the liquid from said membrane by driving the fluid through the membrane.
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Specification