Zenon Environmental Inc.

Zenon Technology Partnership

Mailvaganam Mahendran

Henry Behmann

Steven Kristian Pedersen

Wayne Jerald Henshaw

Ake A Deutschmann

Kenneth Paul Goodboy

Jinhua Bai

Carlos Fernando F Rodrigues

Carlos F Rodrigues

Luigi Fabbricino

Steven Khristian Pedersen

A membrane filtration device has a multiplicity of hollow fiber membranes, or fibers, unconfined in a shell of a module; a first header and a second header disposed in vertically spaced-apart relationship; said first header and said second header having opposed ends of each fiber sealingly secured therein, all open ends of said fibers open to a permeate-discharging face of at least one header; permeate collection means to collect said permeate, sealingly connected in open fluid communication with a permeate-discharging face of at least one of said headers; means to withdraw said permeate; said fibers, said headers and said permeate collection means together forming an integrated combination wherein said fibers are essentially vertically disposed and ends of individual fibers are potted in closely spaced-apart relationship in cured resin; with opposed faces at a fixed distance; each of said fibers having a length from 0.1% to less than 5% greater.

Membrane filtration module with adjustable header spacing

A filtration device is provided for withdrawing permeate essentially continuously from a multicomponent aqueous substrate containing growing microorganisms in a reservoir. A vertical skein of fiber is scrubbed with coarse bubbles which emanate from a conversion baffle positioned under the skein. The substrate is aerated with fine bubbles in a size range small enough to transfer oxygen to the substrate efficiently. The baffle traps the fine bubbles and converts them to coarse bubbles which are effective to scrub the fibers. In the most preferred embodiment, the finished headers of the skein are derived from composite headers comprising a fixing lamina of resin in which the fibers are potted near their terminal ends, and a fugitive lamina of fugitive powdery material in which the terminal ends of the fibers are potted. The fugitive lamina is removed, preferably by dissolving the powder, e.g. finely divided common salt in water.

Apparatus for withdrawing permeate using an immersed vertical skein of hollow fibre membranes

A gas-scrubbed vertical cylindrical skein of 'fibers' has their opposed terminal portions held in headers unconfined in a modular shell, and aerated with a cleansing gas supplied by a gas-distribution means which produces a mass of bubbles serving the function of a scrub-brush for the outer surfaces of the fibers. The skein is surprisingly effective with relatively little cleansing gas, the specific flux through the membranes reaching an essentially constant relatively high value because the vertical deployment of fibers allows bubbles to rise upwards along the outer surfaces of the fibers. The effectiveness is critically dependent upon the length of each fiber in the skein. That length is in the range from at least 0.1% more than the fixed distance between opposed faces of the skein's headers, but less than 5% greater than the fixed distance. Lack of tension allows the fibers to sway in bubbles flowing along their outer surfaces making them surprisingly resistant to being fouled by buildup of deposits of inanimate particles or microorganisms in the substrate. For use in a large reservoir, a bank of skeins is used with a gas distributor means which has fibers preferably &#x3e;0.5 meter long, which together provide a surface area &#x3e;10 m. The terminal end portions of fibers in each header are kept free from fiber-to-fiber contact with a novel method of forming a header.

Vertical cylindrical skein of hollow fiber membranes and method of maintaining clean fiber surfaces

A process is described for withdrawing filtered permeate from a non-pressurized substrate in a reservoir through an assembly. The assembly has a plurality of hollow fiber filtering membranes disposed generally vertically between two solid bodies, an enclosure sealed to the upper solid body to define a cavity, a permeate port in communication with the cavity and the lumen of each membrane in fluid communication with the port via the cavity. A suction is applied to lumens of the membranes via the permeate port to withdraw permeate. A gas is directed to provide bubbles which contact the membranes. Feed water is added so that the membranes are immersed while applying the suction.

A vertical skein of 'fibers', opposed terminal portions of which are held in headers unconfined in a modular shell, is aerated with a gas-distribution means which produces a mass of bubbles serving the function of a scrub-brash for the outer surfaces of the fibers. The membrane device is surprisingly effective with relatively little cleansing gas, the specific flux through the membranes reaching an essentially constant relatively high value because the vertical deployment of fibers allows bubbles to rise upwards along the outer surfaces of the fibers. Further, bubbles flowing along the outer surfaces of the fibers make the fibers surprisingly resistant to being fouled by build-up of deposits of inanimate particles or microorganisms in the substrate provided that the length of each fiber is only slightly greater than the direct center-to-center distance between opposed faces of the headers, preferably in the range from at least 0.1% to about 5% greater. For use in a larger reservoir, a bank of skeins is used with a gas distributor means and each skein has fibers preferably &#x3e;0.5 meter long, which together provide a surface area &#x3e;10 m. The terminal end portions of fibers in each header are kept free from fiber-to-fiber contact with a novel method of potting fibers.

Vertical skein of hollow fiber membranes and method of maintaining clean fiber surfaces while filtering a substrate to withdraw a permeate

An apparatus is described for withdrawing filtered permeate from a substrate contained in a reservoir at ambient pressure. The apparatus includes a plurality of membrane assemblies. Each assembly has a plurality of hollow fiber filtering membranes, immersed in the reservoir, at least one permeating header with the membranes sealingly secured therein, and a permeate collector to collect the permeate sealingly connected to the at least one permeating header and in fluid communication with lumens of the membranes. The membranes of each assembly extend generally vertically upwards from a first header during permeation. One or more sources of suction are provided in fluid communication with the lumens of the membranes of each assembly through the permeate collectors and apply sufficient suction to withdraw permeate from the lumens of the membranes. An aeration system for discharging bubbles assists in keeping the membranes clean. In other aspects, a method of removing fouling materials from the surface of a plurality of porous membranes includes providing, from within a membrane module, gas bubbles in a uniform distribution relative to the membranes. The bubbles move past the surfaces of the membranes to dislodge fouling materials from them. The membranes are arranged in close proximity to one another and mounted to prevent excessive movement.

Apparatus incorporating potted hollow fibre membranes has a solid mass of potting material having a first face, a plurality of hollow fibre membranes sealed in the potting material. Portions of the membranes adjacent open ends of the membranes protrude from the first face. The potting material extends to and adhesively secures to the inner periphery of a permeate collection means to form a permeate collection zone. The permeate collection means may have walls enclosing a plenum adapted to receive a gas. The apparatus may have an air tube passing through the potting material and having an end in communication with a plenum or manifold adapted to receive a gas.

Apparatus incorporating potted hollow fiber membranes

Apparatus for withdrawing permeate using an immersed vertical skein of hollow fiber membranes

A method of potting a plurality of hollow fiber membranes into a mass of solidified potting liquid is described. Open ends of a plurality of hollow fiber membranes are enclosed in a first material held in a container which may be a part of a permeate collection means, for example, a permeate pan or header enclosure. A potting liquid is flowed into the container over the first material. The potting liquid surrounds each hollow fiber membrane and then becomes a solid mass that provides a fluid-tight seal to the outside of the hollow fiber membranes. The first material prevents the potting liquid or solid mass from closing the ends of the membranes. The first material is later removed from the ends of the hollow fiber membranes.

Method of potting hollow fiber membranes

An apparatus for treating a multi component liquid substrate while leaving particulate matter therein as a skein of hollow fiber filtering membranes immersed in the substrate which is contained in a non-pressurized reservoir. A pumping fluid communication with the lumens of the membranes draws a component of the substrate as permeate through the membranes by applying a section to the lumens of the membranes. In various embodiments, an aeration system as a gas distributor for discharging air directly into the substrate within the skein, upper and lower headers of the skein are spaced apart by a gas tube, and a gas distribution system has through passages through the lower header to discharge bubbles into the substrate above the lower header.

An asymmetric membrane comprising a tubular polymer film in combination with a tubular braid on which the film is supported, requires the braid be macroporous and flexible, yet sufficiently strong to withstand continuous flexing, stretching and abrasion during use for microfiltration (MF) or ultrafiltration (UF). The specifications for a braid of a long-lived membrane are provided. A membrane is formed by supporting a polymer film in which particles of calcined &agr;-alumina are dispersed, on the defined tubular braid.

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Mississauga, Canada

Mailvaganam Mahendran