# US 5,350,522 A · Effluent treatment

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- Number: US 5,350,522 A
- Document ID: US5350522A
- Status: Granted
- Kind: A
- Application number: 07/984,415
- Filed: 1993-03-04
- Granted: 1994-09-27
- Earliest claimed: 1990-09-07
- Assignees: Eastman Kodak Company
- Inventors: John R. Fyson
- Web page: https://patentgrep.com/patent/US5350522A

## CPC

- C02F 9/00: Multistage treatment of water, waste water or sewage
- C02F 1/283: {using coal, charred products, or inorganic mixtures containing them}
- C02F 1/42: by ion-exchange (ion-exchange in general B01J)
- C02F 1/722: {Oxidation by peroxides}
- C02F 2101/20: Heavy metals or heavy metal compounds
- C02F 2101/203: {Iron or iron compound}
- C02F 2101/303: {Complexing agents}
- C02F 2103/40: from the manufacture or use of photosensitive materials
- C02F 2209/44: Time
- Y10S 210/912: Heavy metal
- 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)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method for treating photographic effluent to remove harmful pollutants and which reduces silver and iron ion concentrations in the effluent to no more than about 2 ppm is disclosed. The method includes an oxidation step to convert reducing sulfur compounds to oxidized products; a heavy metal ion precipitation step; a step of adding a developing agent absorbent and a sequestering agent absorbent; and a step of separating a produced solid phase from a liquid phase. The separated Liquid phase is environmentally acceptable.

## Claims

### Claim 1

A method of treating a photographic effluent to remove harmful pollutants, including heavy metal ions comprising silver and iron ions, comprising:
(a) providing a vessel containing a liquid photographic effluent that includes harmful pollutants;
(b) introducing into said vessel an oxidizing agent selected from the group consisting of hydrogen peroxide, a percarbonate, a permanganate, a perchromate, a persulfate, a perphosphate, or a perborate to convert reducing sulfur compounds to oxidized products;
(c) after a period of time sufficient for said oxidizing agent to convert reducing sulfur compounds to oxidized products, introducing into said vessel chemical reagents comprising a heavy metal ion precipitant selected from a metal hydroxide, oxide or carbonate, a developing agent absorbent, and a sequestering agent absorbent, thereby producing a mixture comprising a solid phase and an environmentally acceptable liquid phase;
(d) separating and removing said solid phase from said liquid phase, wherein said liquid phase has silver and iron ions in a concentration of each of no more than about 2ppm; and
(e) disposing of said solid phase.

### Claim 2

A method according to claim, 1 wherein said oxidizing agent is hydrogen peroxide.

### Claim 3 (depends on 1)

A method according to claim 1 wherein said oxidizing agent is sodium percarbonate.

### Claim 4 (depends on 1)

A method according to claim 1 wherein said heavy metal ion precipitant comprises a Group II metal hydroxide.

### Claim 5 (depends on 4)

A method according to claim 4 wherein said Group II metal hydroxide is calcium hydroxide.

### Claim 6 (depends on 1)

A method according to claim 1 wherein said developing agent absorbent is activated carbon.

### Claim 7 (depends on 1)

A method according to claim 1 wherein said sequestering agent absorbent comprises an ion-exchange resin.

### Claim 8 (depends on 1)

A method according to claim 1 wherein said sequestering agent precipitant comprises a Group III or transition metal salt.

### Claim 9 (depends on 8)

A method according to claim 8 wherein said metal salt is aluminum sulfate.

### Claim 10 (depends on 1)

A method according to claim 1 wherein said precipitant and said absorbent are introduced sequentially.

### Claim 11 (depends on 1)

A method according to claim 1 wherein said precipitant and said absorbent are introduced simultaneously.

### Claim 12 (depends on 1)

A method according to claim 1 wherein said separating and removing said solid phase from said liquid phase is carried out by filtration, settling, or centrifugation.

### Claim 13 (depends on 1)

A method according to claim 1 further comprising adding an inert filtration-assisting powder prior to said separating and removing said solid phase from said liquid phase.

### Claim 14 (depends on 1)

A method according to claim 1 wherein said oxidizing agent is hydrogen peroxide or sodium percarbonate, said heavy metal ion precipitant is a Group II metal hydroxide, and said developing agent absorbent is activated carbon, said method further comprising introducing into said vessel, following the introduction of said chemical reagents and prior to separating and removing said solid phase from said liquid phase, a sequestering agent absorbent comprising an ion-exchange resin.