Backwash
First Claim
1. A method of backwashing one or more membranes in a vessel, the method comprising:
- removing liquid to be treated from the vessel until a level of the liquid falls to a first level within the vessel below an upper level of the one or more membranes, wherein the removal of liquid to be treated is at least partially accomplished by a filtration operation;
suspending the removal of the liquid to be treated from the vessel when the level of the liquid to be treated falls to the first level;
performing a liquid backwash of the one or more membranes when the first level is reached by the removal of the liquid to be treated from the vessel until the level of the liquid collected in the vessel comprising backwashed liquid is at a predetermined level above said first level;
aerating a membrane surface of the one or more membranes; and
removing liquid containing fouling materials dislodged from the membrane surface from the vessel;
wherein the predetermined level provides sufficient liquid in the vessel to immerse an upper header of the one or more membranes during the aerating of the membrane surface.
11 Assignments
0 Petitions
Accused Products
Abstract
A method of backwashing a membrane filtration module (4), said module (4) including one or more membranes (5) located in a feed-containing vessel (3), the membranes (5) having a permeable wall which is subjected to a filtration operation wherein feed containing contaminant matter is applied to one side of the membrane wall and filtrate is withdrawn from the other side of the membrane wall, the method including: removing liquid from the feed-containing vessel (3) until the level of liquid in the feed-containing vessel (3) falls to a first level (L2) below an upper level of the membranes; suspending the filtration operation; performing a liquid backwash of the membrane wall until liquid level within the feed-containing vessel (3) rises to a second predetermined level (L1) above said first level; aerating the membrane surface with gas bubbles to dislodge fouling materials therefrom; performing a sweep or drain down of the feed-containing vessel (3) to remove the liquid containing the dislodged contaminant matter; and recommencing the filtration operation.
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Citations
24 Claims
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1. A method of backwashing one or more membranes in a vessel, the method comprising:
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removing liquid to be treated from the vessel until a level of the liquid falls to a first level within the vessel below an upper level of the one or more membranes, wherein the removal of liquid to be treated is at least partially accomplished by a filtration operation; suspending the removal of the liquid to be treated from the vessel when the level of the liquid to be treated falls to the first level; performing a liquid backwash of the one or more membranes when the first level is reached by the removal of the liquid to be treated from the vessel until the level of the liquid collected in the vessel comprising backwashed liquid is at a predetermined level above said first level; aerating a membrane surface of the one or more membranes; and removing liquid containing fouling materials dislodged from the membrane surface from the vessel; wherein the predetermined level provides sufficient liquid in the vessel to immerse an upper header of the one or more membranes during the aerating of the membrane surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of backwashing a membrane filtration module in a vessel, said module including one or more membranes, the method comprising:
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removing liquid from the vessel until a level of the liquid falls to a first level within the vessel below an upper level of the one or more membranes, wherein the removal of liquid from the vessel is at least partially accomplished by a filtration operation; suspending the removal of the liquid from the vessel when the level of the liquid falls to the first level; performing a liquid backwash of the one or more membranes, after removing the liquid from the vessel, until the level of liquid in the vessel rises to a predetermined level above the first level; initiating aeration of the membrane surfaces of the one or more membranes after the liquid backwash is completed; and removing liquid containing fouling materials dislodged from the membrane surfaces from the vessel, after aerating of the membrane surfaces is completed; wherein the acts of removing liquid from the vessel, performing a liquid backwash, aerating membrane surfaces, and removing liquid containing fouling materials are performed within a single cycle, and wherein the predetermined level provides sufficient liquid in the vessel to immerse an upper header of the membrane filtration module during the aeration of the membrane surfaces. - View Dependent Claims (20, 21, 22)
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23. A method of treating water, comprising:
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introducing water to be treated into a vessel; filtering the water to be treated through membranes immersed in the water; reducing a level of the water to be treated to a first level within the vessel below an upper level of the membranes, wherein the reduction of the level of the water to be treated is at least partially accomplished by a filtration operation; commencing a backwash of the membranes when the first level is reached by the reduction of the level of water to be treated, the backwash continuing until a level of a water solution comprising backwashed liquid in the vessel rises to a second predetermined level above the first level; and aerating the membranes; wherein the second predetermined level provides sufficient liquid in the vessel to immerse an upper header of the membranes during the aeration of the membranes. - View Dependent Claims (24)
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Specification