Method of operating membrane filter

Abstract

A method of operating an immersed microporous membrane module includes a step of monitoring membrane performance to sense the onset of sludging in the module. Differences in permeability between permeation in backwashes, or trends in permeability during backwashing and permeability during permeation, or both, are monitored. Solid deposits formed during the onset of sludging may be removed with an in situ de-sludging process. For example, the deposits may be removed by stopping permeation while aerating the module, optionally at an increased rate. At other times, the module is optionally aerated while permeate is withdrawn at an aeration rate correlated to flux. The method may be used in particular with a membrane module having parallel textured flat sheet membranes suspended between a pair of vertically oriented headers. An aerator may be made from an open bottomed channel having an array of holes rising and concentrated towards the center of the channel.

Dependencies are inferred from the claim text.