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US 10,118,844 B2Granted
Multifunctional method for membrane protection and biofouling control
AssigneeEcolab USA Inc.
InventorsAmit Gupta, Harshada Lohokare
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Abstract
The invention provides methods and compositions for the protection of a membrane from both biofouling and from damage caused by a biocide. The invention utilizes PAA as both a biocide and as a reducing agent for other oxidizing biocides. This is especially beneficial because without the invention one would be forced to choose between preventing membrane biofouling or preventing membrane damage from oxidizing biocides.
Claims7
A method of preserving the effectiveness of a membrane in a water process flow, comprising:
- adding a composition comprising hydrogen peroxide to the water process flow upstream from the membrane, the water process flow comprising sodium hypochlorite;
- adding peracetic acid or peroxyacetic acid to the water process flow downstream from the addition of the composition and upstream from the membrane in an amount sufficient to inhibit growth of a biofilm on the membrane;
- and
- contacting the hydrogen peroxide with the sodium hypochlorite before the hydrogen peroxide contacts the membrane,
- wherein the contacting the hydrogen peroxide with the sodium hypochlorite results in conversion of at least some of the hydrogen peroxide into molecular oxygen and water,
- wherein the membrane is a reverse osmosis membrane,
- wherein the amount sufficient to inhibit the growth of the biofilm on the membrane is about 0.1 ppm to about 15 ppm.
4 more elements
Dependencies are inferred from the claim text.