CLEANING IN MEMBRANE FILTRATION SYSTEMS

摘要

A method of cleaning permeable, hollow membranes (6) in an arrangement of the
type wherein a pressure differential is applied across the walls (15) of the
permeable, hollow membranes (6) immersed in a liquid suspension, the liquid
suspension being applied to the outer surface of the porous hollow membranes
(6) to induce and sustain filtration through the membrane walls (15) wherein
some of the liquid suspension passes through the walls (15) of the membranes
(6) to be drawn off as clarified liquid or permeate from the hollow membrane
lumens (7), and at least some of the solids are retained on or in the hollow
membranes (6) or otherwise as suspended solids within the liquid surrounding
the membranes (6). The method of cleaning comprises the steps of applying a
cleaning solution (14) to one side of the membrane wall (15); applying a
pressure differential across the membrane wall (15) to cause flow of the
cleaning solution (14) through the wall (15) from the one side of the membrane
wall (15) to the other side of the membrane wall (15) and applying a reverse
pressure differential across the membrane wall (15) to cause flow of the
cleaning solution (14) through the wall (15) from the other side of the
membrane wall (15) back to the one side of the membrane wall (15). A method of
determining the amount of chemical cleaning solution required is also
disclosed.