# US 5,350,516 A · Control of odor and septicity and purification of sewage and wastewater

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- Number: US 5,350,516 A
- Document ID: US5350516A
- Status: Granted
- Kind: A
- Application number: 07/933,320
- Filed: 1992-08-21
- Granted: 1994-09-27
- Earliest claimed: 1991-12-27
- Inventors: Amal K. Bhadra
- Web page: https://patentgrep.com/patent/US5350516A

## CPC

- C02F 1/72: by oxidation {(C02F1/4672 takes precedence)}
- C02F 1/725: {by catalytic oxidation}
- Y10S 210/916: Odor, e.g. including control or abatement
- 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

This invention is a process for controlling odor and septicity of sewage or wastewater and for purifying sewage or wastewater by biological active substances, A source of sulfur dioxide is added to sewage or wastewater along with metal catalyst and sewage or wastewater is aerated. The effect of this treatment is to reduce the generation of hydrogen sulfide and the odor and corrosion associated with this compound and to reduce the need for aeration in the treatment of sewage or wastewater and to purify sewage or wastewater by increasing the metabolic activities of biological active substances added therein, This results in substantial savings in aeration costs.

## Claims

### Claim 1

A process for treating sewage or wastewater for control of odor and septicity and for purification thereof, comprising the steps of:
adding to said sewage or wastewater to be treated a source of sulfur dioxide selected from the group consisting of sulfur dioxide, sulfite, bisulfite, metabisulfite, sulfurous acid, pyrosulfite, and mixtures thereof;
adding a metal salt catalyst to said sewage or wastewater to be treated, and
aerating the sewage or wastewater.

### Claim 2 (depends on 1)

The process of claim 1 wherein said source of sulfur dioxide is dissolved in water prior to being added to the sewage or wastewater.

### Claim 3 (depends on 1)

The process of claim 1 wherein said sulfite, bisulfite, metabisulfite, and pyrosulfite are added to the sewage or wastewater as alkali or alkaline earth metal salt.

### Claim 4 (depends on 1)

The process of claim 1 wherein said source of sulfur dioxide is added at a concentration of 1 to 300 parts of active sulfur dioxide per million parts of sewage or wastewater being treated.

### Claim 5 (depends on 1)

The process of claim 1 wherein said source of sulfur dioxide is added at a concentration of 2 to 30 parts of active sulfur dioxide per million parts of sewage or wastewater being treated.

### Claim 6 (depends on 1)

The process of claim 1 wherein said source of sulfur dioxide is dissolved in a solution of lime or ammonium hydroxide or soda ash, or mixtures thereof, prior to being added to the sewage or wastewater.

### Claim 7 (depends on 1)

The process of claim 1 wherein said source of sulfur dioxide is in the gaseous, liquid or solid state.

### Claim 8 (depends on 1)

The process of claim 1 wherein said source of sulfur dioxide is in the form of sulfurous acid or sulfurous acid dissolved in water.

### Claim 9 (depends on 1)

The process of claim 1 wherein said metal salt catalyst is selected from the group consisting of iron, copper, cobalt, nickel, chromium, manganese, titanium, and vanadium salts.

### Claim 10 (depends on 1)

The process of the claim 1 wherein the metal cation of said metal salt catalyst may be present in any valency state from 0 to 8, wherein said metal salt catalyst is selected from the group consisting of nitrate, nitrite, sulfate, sulfite, chloride, and phosphate salts, and wherein said catalyst is added at a concentration of 0.1 to 25 ppm metal.

### Claim 11 (depends on 1)

The process of claim 1 wherein the metal salt catalyst is ferric chloride and wherein said ferric chloride is added at a concentration of 0.01 to 25 ppm iron as Fe.

### Claim 12 (depends on 11)

The process of claim 11 wherein said ferric chloride is added at a concentration of 1 to 8 ppm iron as Fe.

### Claim 13 (depends on 1)

The process of claim 1 wherein the metal salt catalyst is ferric sulfate and wherein said ferric sulfate is added at a concentration of 0.01 to 25 ppm iron as Fe.

### Claim 14 (depends on 13)

The process of claim 13 wherein said ferric sulfate is added at a concentration of 1 to 8 ppm iron as Fe.

### Claim 15 (depends on 1)

The process of claim 1 wherein the metal salt catalyst is a mixture of more than one metal salt.

### Claim 16 (depends on 1)

The process of claim 1 wherein the metal salt catalyst comprises a mixture of different metal salts added at different concentrations.

### Claim 17 (depends on 1)

The process of claim 1 wherein said metal salt catalyst comprises a mixture of iron and copper salts, wherein concentration range of iron is from 0.5 to 25 ppm as Fe and the concentration range of copper is from 0.01 to 3 ppm as Cu.

### Claim 18 (depends on 1)

The process of claim 1 wherein aeration is done by any oxygen containing gas.

### Claim 19 (depends on 1)

The process of claim 1 wherein a biological active substance selected from the group consisting of activated sludge, algae, and aquatic plants, and mixtures thereof, and is added to the sewage or wastewater after addition of said source of sulfur dioxide.

### Claim 20 (depends on 1)

The process of claim 1 wherein an oxidizing agent is added to the sewage or wastewater to initiate oxidation of said source of sulfur dioxide.

### Claim 21 (depends on 1)

The process of claim 1 wherein addition of said source of sulfur dioxide or mixtures thereof, to wastewater or sewage, sewage systems, and sewage conduit reduces the corrosion of the treatment plants and sewage conduit.

### Claim 22 (depends on 1)

The method of claim 1, wherein said process is a process for treating sewage.

### Claim 23

A process of treating sewage or wastewater for control of odor and septicity and for purification thereof, comprising the steps of:
adding to said sewage or wastewater a source of sulfur dioxide selected from the group consisting of sulfur dioxide, sulfite, bisulfite, metabisulfite, pyrosulfite, sulfurous acid, and mixtures thereof;
adding a biologically active substance selected from the group consisting of activated sludge, algae, aquatic plants, and mixtures thereof to the sewage or wastewater after the addition of said source of sulfur dioxide, and
aerating the sewage or water.

### Claim 24 (depends on 23)

The process of claim 23 wherein aeration is done by any oxygen containing gas.

### Claim 25 (depends on 23)

The method of claim 23, wherein said process is a process for treating sewage.

### Claim 26

A process of treating sewage or wastewater for control of odor and septicity and purification thereof, comprising the steps of:
adding to said sewage or wastewater to be treated a source of sulfur dioxide selected from the group consisting of sulfur dioxide, sulfite, bisulfite, metabisulfite, pyrosulfite, sulfurous acid, and mixtures thereof;
adding a metal salt catalyst to the sewage or wastewater; and
adding a biologically active substance selected from the group consisting of activated sludge, algae, aquatic plants, and mixtures thereof to said sewage or wastewater after the addition of said source of sulfur dioxide.

### Claim 27 (depends on 26)

The method of claim 26, wherein said process is a process for treating sewage.

### Claim 28

A process of treating sewage or wastewater for control of odor and septicity and purification thereof, consisting of the steps of:
adding 1 to 300 ppm of a source of sulfur dioxide selected from the group consisting of sulfur dioxide, sulfite, bisulfite, metabisulfite, sulfurous acid, pyrosulfite, solution of sulfur dioxide in sodium hydroxide, a solution of sulfurous acid in sodium hydroxide, and mixtures thereof to a million parts of sewage or wastewater; and
adding a biologically active substance selected from the group consisting activated sludge, algae, aquatic plants, and mixtures thereof to said sewage or wastewater after the addition of said source of sulfur dioxide.

### Claim 29 (depends on 28)

The method of claim 28, wherein said process is a process for treating sewage.