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US 7,025,885 B2Granted
Water filtration using immersed membranes
AssigneeZenon Environmental Inc.
InventorsPierre Cote, Arnold Janson, Hadi Husain, Manwinder Singh, Nicholas Adams
Life of this patent
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Abstract
A process for operating filtering membranes submerged in a tank involves, in one aspect, periodically deconcentrating the tank by partially emptying and refilling the tank with fresh water. The emptying and refilling may be performed generally simultaneously or sequentially. In another embodiment, the membrane modules are arranged in a series of filtration zones between a feed water inlet and a retentate outlet of a tank and the zone adjacent the outlet is emptied and refilled.
Claims8
A process for filtering water comprising,
- (a) introducing a feed water containing an initial concentration of solids into an open tank to immerse one or more filtering membranes located in the open tank, the feed water contacting a first side of the membranes;
- and
- (b) in repeated cycles,
- (i) applying suction on a second side of the membranes to withdraw a filtered permeate while adding sufficient feed water to keep the membranes submerged and permitting the concentration of solids in the water in the tank to rise to an increased concentration;
- and,
- (ii) partially deconcentrating the tank by (A) draining a volume of water equal to between about 75% to 20% of the volume of the water in the tank at the end of step (i) from the tank and (B) introducing a similar volume of feed water into the tank.
3 more elements
Dependencies are inferred from the claim text.