# US 10,118,844 B2 · Multifunctional method for membrane protection and biofouling control

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,118,844 B2
- Document ID: US10118844B2
- Status: Granted
- Kind: B2
- Application number: 14/586,989
- Filed: 2014-12-31
- Published: 2016-06-30
- Granted: 2018-11-06
- Earliest claimed: 2014-12-31
- Assignees: Ecolab USA Inc.
- Applicants: Ecolab USA Inc.
- Inventors: Amit Gupta; Harshada Lohokare
- Web page: https://patentgrep.com/patent/US10118844B2

## CPC

- C02F 1/722: {Oxidation by peroxides}
- B01D 65/08: Prevention of membrane fouling or of concentration polarisation
- B01D 2321/02: Forward flushing
- B01D 2321/162: Use of acids
- B01D 2321/168: Use of other chemical agents
- C02F 1/44: by dialysis, osmosis or reverse osmosis {(general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268)}
- C02F 1/4693: {electrodialysis}
- C02F 1/4695: {electrodeionisation}
- C02F 1/70: by reduction {(C02F1/4676 takes precedence)}
- C02F 1/76: with halogens or compounds of halogens {(C02F1/4674 takes precedence)}
- C02F 2103/08: Seawater, e.g. for desalination
- C02F 2303/04: Disinfection
- C02F 2303/185: The treatment agent being halogen or a halogenated compound
- C02F 2303/20: Prevention of biofouling
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## 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.

## Claims

### Claim 1

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.

### Claim 2 (depends on 1)

The method of claim 1, wherein the composition comprises 1-50% by weight of the hydrogen peroxide.

### Claim 3 (depends on 1)

The method of claim 1, further comprising the step of removing precipitated ions from the water process flow.

### Claim 4 (depends on 1)

The method of claim 1, wherein the molecular oxygen is produced in an amount sufficient to reduce a population of microorganisms in the water process flow.

### Claim 5 (depends on 1)

The method of claim 1, wherein the water process flow comprises water that is selected from the group consisting of: river water, sea water, desalinated water, brackish water, well water, aquifer water, pond water, wastewater, recirculated water, sewage water, purified water, de-oxygenated water, and any combination thereof.

### Claim 6 (depends on 1)

The method of claim 1, wherein the membrane is in operation.

### Claim 7 (depends on 1)

The method of claim 1, wherein the membrane is not in operation.