Module cleaning method

Abstract

An aeration/backwash device ( 16 ) for use with a porous membrane filtration module ( 5 ) including one or more membranes ( 6 ) extending longitudinally between vertically spaced upper ( 7 ) and lower headers ( 8 ) into which the ends of the membranes are potted. The membranes ( 6 ) having a permeable wall which, in use, 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operation wherein feed containing contaminant matter is applied to one side of the membrane wall and filtrate is withdrawn from the other side of the membrane wall.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 aeration/backwash device ( 16 ) adapted to at least partially surround a portion of said membrane module ( 5 ) and including a communication chamber ( 17 ) having spaced through-openings ( 18, 19 ) in fluid communication with the chamber ( 17 ) and the membrane module ( 5 ). In use, gas is supplied to the chamber ( 17 ) and communicated to the membrane module ( 5 ) through the through-openings ( 18, 19 ) to aerate the membranes within the membrane module and liquid backwash is withdrawn from and/or fed into the membrane module ( 5 ) through the throughopenings into the chamber ( 17 ).

1 - 22 . (canceled) 
   
   
       23 . A method of removing contaminant material from a feed liquid using a porous membrane filtration module including one or more membranes extending longitudinally between vertically spaced upper and lower headers into which the ends of the membranes are potted, the membranes having a permeable wall which, in use 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operation wherein feed containing contaminant matter is applied to one side of the membrane wall and filtrate is withdrawn from the other side of the membrane wall, the upper and lower headers being in fluid communication with one or both of the ends of said membranes and at least one associated upper and/or lower filtrate collection chamber such that, in use, filtrate withdrawn from said other side of the membrane wall is communicated through at least one of the upper and/or lower header to the associated upper and/or lower collection chambers, an aeration/backwash device at least partially surrounding a portion of said membrane module and including a communication chamber having spaced through-openings in fluid communication with said communication chamber and the membrane module, wherein in use, gas is supplied to the communication chamber and communicated to the membrane module through said through-openings to aerate the membranes withing the membrane module and liquid backwash is withdrawn from and/or fed into the membrane module through said through-openings into said communication chamber comprising the steps of:
 (a) performing a filtration operation whereing 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;   (b) communicating said withdrawn filtrate through at least one of the upper and/or lower headers to at least one of the upper and/or lower collection chambers;   (c) supplying gas to the communication chamber and communicating said gas to the membrane module through said through-openings to aerate the membranse within the membrane module;   (d) backwashing said membrane wall using a liquid; and   (e) withdrawing liquid backwash from the membrane module through said through-openings into said communication chamber.   
   
   
       24 . A method according to  claim 23  wherein the gas and liquid backwash are selectively communicated and withdrawn through the same through-openings. 
   
   
       25 . A method according to  claim 24  wherein the gas is supplied to the chamber and communicated to the membrane module through the upper of said through-openings to aerate the membranes withing the membrane module and liquid backwash is withdrawn from and/or fed into the membrane module throug at least the lower of said through-openings into said chamber. 
   
   
       26 . A method according to  claim 23  including feeding the backwash or feed liquid into the base of the module through the lower openings or both set of openings. 
   
   
       27 . A method according to  claim 23  including using the backwash and/or feed liquid to sweep solids along the membranes to carry out solids removed from the membrane surfaces during said aeration. 
   
   
       28 . A method according to  claim 23  wherein the membrane module is submerged in feed liquid contained within a vessel and including the step of flushing backwash containgn the solides from the vessel by overflowing at the top of the vessel. 
   
   
       29 . A method according to  claim 23  including the step of flushing backwash waste containing the solids from the module by overflowing at the top of the module. 
   
   
       30 . A method according to  claim 23  including the step of flushing backwash waste containing the solids from the module by draining or pumping the waste from the module through the openings. 
   
   
       31 . A method according to  claim 27  including the step of introducing gas into the module during said flushing step. 
   
   
       32 . A method according to  claim 31  wherein said gas is mixed with said backwash andoro feed liquid. 
   
   
       33 . A method according to  claim 31  wherein said gas is introduced to said communication chamber.