IMMERSED MEMBRANE MODULE AND PROCESS

摘要

An element for use in ultrafiltration or microfiltration of potable water has a large number of small diameter hollow fibre membranes attached in a slightly slackened state between two headers but in fluid communication with only one of the headers. Side plates attached to the sides of the headers define vertical flow channels containing the membranes. The headers, membranes, side panels and T connectors define membrane elements which may be placed side by side with other elements to create membrane modules which can be stacked on top of each other to form membrane cassettes of various sizes having continuous vertical flow channels through the entire cassette. To pot the fibres, a suitable number o f fibres are gathered in a bundle and dipped in a pool of liquid wax which freezes seconds after the bundle of fibres are removed. The waxed fibre bundle is then inserted into a recess in a header. Potting resin is poured into the header to cover the fibre bundle to a depth greater than the distan ce that the wax wicked up the fibres. The wax is melted out of the header. The membrane modules or cassettes are arranged in an open tank to cover a substantial part of the cross sectional area of the tank, preferably 80% or more. In first and second processes, tank water flows upwards and downwards through the flow channels respectively.