Membrane bioreactor having single header membrane module

Abstract

A filtration apparatus for filtering liquid has a filtration cell having generally vertical front and rear panels spaced apart to define a cell length, and generally vertical side panels extending between the front and rear panels and spaced apart to define a cell width. A plurality of header segments are provided in the cell, each header segment having a permeate channel. A plurality of hollow fiber membranes are associated with each header segment and extend generally upright between the cell panels, each membrane having a lumen in flow communication with the permeate channel of the associated header segment and a lower end secured to the associated header segment and a loose upper end.

Description

PRIORITY CLAIM [0001] This is an application claiming the benefit under 35 USC 119(e) of U.S. Provisional Application Nos. 60 / 512,700, which was filed on Oct. 21, 2003, and U.S. Application No. [Attorney Ref: 4320-610], entitled “Membrane Bioreactor Having Single Header Membrane Module”, which was filed on Oct. 1, 2004. The entire contents of U.S. Ser. No. 60 / 512,700 and U.S. Ser. No. [Attorney Ref: 4320-610] are hereby incorporated herein in their entirety by this reference to them.FIELD OF THE INVENTION [0002] This invention relates to membrane modules for water treatment. BACKGROUND OF THE INVENTION [0003] Immersed membranes are used for extracting clean water (permeate) from a tank of contaminated water or mixed liquor. The membranes are often provided in the form of assembled modules, each module having many hollow fiber membranes extending between two headers for collecting permeate that passes through pores of the membrane walls into the lumina of the membranes. Streams of ai...

AI Technical Summary

Benefits of technology

[0012] According to a fourth aspect of the present invention, a method for filtering liquid includes providing a filtration apparatus having (i) a filtration cell with generally vertical front and rear panels spaced apart to define a cell length, and generally vertical side panels extending between the front and rear panels and spaced apart to define a cell width, (ii) a plurality of header segments the cell, each header segment having a permeate channel, and (iii) a plurality of hollow fiber membranes associated with each header segment and extending generally upwards from the associated header segment, each membrane having a lumen in flow communication with the permeate channel of the associated header segment and a lower end secured to the associated header segment and a loose upper end. The method further includes immersing the apparatus in a liquid at ambient pressure, applying suction to the lumens to withdraw permeate, and aerating the liquid such that fluid currents rise upwards along the outer surfaces of the hollow fiber membranes, urging the membranes to a generally vertical position when aerated.

[0013] According to a fifth aspect of the present invention, a method for filtering liquid includes providing a filtration apparatus having (i) an enclosure, (ii) a divider structure in the enclosure and dividing the enclosure into a plurality of filtration cells, each cell having generally vertical front and rear panels spaced apart to define a cell length, and generally vertical side panels extending between the front and rear panels and spaced apart to define a cell width, (iii) a plurality of header segments in each cell, each header segment having a permeate channel, and (iv) a plurality of hollow fiber membranes associated with each header segment and extending generally upwards from the associated header segment, each membrane having a lumen in flow communication with the permeate channel of the associated header segment and a lower end secured to the associated header and a loose upper end. The method for filtering a liquid further includes immersing the apparatus in a liquid at ambient pressure, applying suction to the lumens to withdraw permeate, and aerating the liquid such that fluid currents rise upwards along the outer surfaces of the hollow fiber membranes, urging the membranes to a generally vertical position when aerated.

[0014] According to a sixth aspect of the present invention, a method for filtering liquid includes providing a filtration apparatus having (i) a plurality of cartridges, each cartridge defining a filt

Problems solved by technology

Although these features improve filtration along a central portion of the length of the fibers, a dead zone remains at either end of the fibers where sufficient cleaning of the fibers and circulation of the water does not occur, thereby causing the fibers at either end to become plugged or fouled by contaminants, and resulting in a corresponding decrease in the filtration capacity of the system.

Presence of the dead zone is primarily caused by the headers themselves, which interfere with the flow of air bubbles and water circulation at either end of the fibers, and which inhibit movement of the fibers since the ends of the fibers are fixed to the headers.

However, single header modules involve various issues such as supporting the fibres, aerating the fibres and building groups of modules.

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