Apparatus and method for cleaning membrane filtration modules

Abstract

A method and apparatus for cleaning a membrane module, the membrane module having a plurality of porous membranes, the membranes being arranged in close proximity to one another and mounted to prevent excessive movement therebetween and means for providing, from within the module, by means other than gas passing through the pores of the membranes, gas bubbles entrained in a liquid flow such that, in use, the liquid and bubbles entrained therein move past the surfaces of the membranes to dislodge fouling materials therefrom, the gas bubbles being entrained in the liquid by flowing the liquid past a source of gas to draw the gas into the liquid flow. The gas bubbles are preferably entrained into the liquid using a venturi type device. The membranes are preferably partitioned into discrete groups to assist cleaning while maintaining high packing density.

1 . A membrane bioreactor comprising: 
 a membrane module comprising a plurality of porous hollow membrane fibers mounted at a first end to a first potting head and at a second end to a second potting head, the membrane module extending longitudinally between the first potting head and the second potting head, the porous hollow membrane fibers comprising a plurality of pores, wherein the porous hollow membrane fibers comprise a plurality of bundles separated by at least one partition at or adjacent to at least one of the potting heads, wherein the first potting head comprises an array of aeration openings formed in the potting head for providing a plurality of gas bubbles within the module such that, in use, the gas bubbles move past outer surfaces of the porous hollow membrane fibers to dislodge fouling materials therefrom; and    a tank into which a feed is introduced, and a source of oxygen for forming an activated sludge within the tank, wherein the module according is positioned within the tank so as to be immersed in the activated sludge, and wherein a filtrate is withdrawn from at least one end of the porous hollow membrane fibers.    
     
     
         2 . The membrane bioreactor according to  claim 1 , wherein the partition is formed by a spacing between bundles.  
     
     
         3 . The membrane bioreactor according to  claim 1 , wherein the bundles are arranged in a cylindrical array and a plurality of partitions extend radially from a center of the array or are positioned concentrically within the cylindrical array.  
     
     
         4 . The membrane bioreactor according to  claim 1 , wherein the aeration openings are positioned to coincide with the spaces formed between the bundles.  
     
     
         5 . The membrane bioreactor according to  claim 1 , wherein at least one aeration opening comprises a slot or a row comprising a plurality of holes, and wherein a bundle is located adjacent to the slot or the row.  
     
     
         6 . The membrane bioreactor according to  claim 1 , wherein the membrane module comprises at least two aeration openings, and wherein a bundle is situated between the aeration openings.  
     
     
         7 . The membrane bioreactor according to  claim 1 , wherein the membrane module comprises at least two bundles, wherein the slot or row is situated between the bundles.  
     
     
         8 . The membrane bioreactor according to  claim 1 , wherein the porous hollow membrane fibers within the membrane module have a packing density of from about 5 to about 70%.  
     
     
         9 . The membrane bioreactor according to  claim 1 , wherein the porous hollow membrane fibers within the membrane module have a packing density of from about 8 to about 55%.  
     
     
         10 . The membrane bioreactor according to  claim 1 , wherein the aeration openings have a diameter or an equivalent diameter averaging from about 1 mm to about 40 mm.  
     
     
         11 . The membrane bioreactor according to  claim 1 , wherein the aeration openings have a diameter or an equivalent diameter averaging from about 1.5 mm and about 25 mm.  
     
     
         12 . The membrane bioreactor according to  claim 1 , wherein an inner diameter of the porous hollow membrane fibers averages from about 0.1 mm to about 5 mm.  
     
     
         13 . The membrane bioreactor according to  claim 1 , wherein an inner diameter of the porous hollow membrane fibers averages from about 0.25 mm to about 2 mm.  
     
     
         14 . The membrane bioreactor according to  claim 1 , wherein an inner diameter of the porous hollow membrane fibers averages from about 0.05 to about 2 mm.  
     
     
         15 . The membrane bioreactor according to  claim 1 , wherein a wall thickness of the porous hollow membrane fibers averages from about 0.1 mm to about 1 mm.  
     
     
         16 . The membrane bioreactor according to  claim 1 , wherein the membranes are arranged in close proximity to one another and are mounted to prevent excessive movement therebetween.  
     
     
         17 . The membrane bioreactor according to  claim 1 , wherein at least one header comprises one or more holes formed therein through which a gas and a liquid flow is introduced.