# US 4,396,513 A · Use of very high charge cationic polymers in biological sludge dewatering

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- Number: US 4,396,513 A
- Document ID: US4396513A
- Status: Granted
- Kind: A
- Application number: 06/300,145
- Filed: 1981-09-08
- Granted: 1983-08-02
- Earliest claimed: 1981-09-08
- Assignees: Betz Laboratories, Inc.
- Inventors: David R. Haldeman
- Web page: https://patentgrep.com/patent/US4396513A

## CPC

- C02F 1/54: using organic material
- 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)

## Abstract

A method of dewatering bio-sludge is disclosed. This method comprises adding to the sludge, an effective amount for the purpose of an acrylamide/dimethylaminoethylmethacrylate methylchloride copolymer having a cationic charge density of 90%.

## Claims

### Claim 1

Method of treating organic sludge of the type which has been treated to increase biological growth therein, comprising adding to said sludge an effective amount of a copolymer flocculant treatment, said copolymer consisting essentially of an acrylamide monomer and a cationic monomer, said cationic monomer comprising a quaternary ammonium salt of N,N dimethylaminoethylmethacrylate, wherein said cationic monomer is present in said copolymer in a molar ratio of about 80-90% cationic monomer: 20-10% acrylamide, said copolymer having a molecular weight of at least about one million, said method further comprising the step of dewatering said sludge.

### Claim 2 (depends on 1)

Method as defined in claim 1 wherein said copolymer comprises an acrylamide/dimethylaminoethylmethacrylate methylchloride polymer.

### Claim 3 (depends on 1)

Method as defined in claim 1 comprising adding said copolymer to said sludge in an amount of about 5 to 50 lbs per ton of sludge.

### Claim 4 (depends on 3)

Method as defined in claim 3 wherein said copolymer has a molecular weight of between about 1 to about 2 million.

### Claim 5 (depends on 1)

Method as defined in claim 1 wherein said dewatering comprises processing said sludge in a belt filter mechanism.

### Claim 6 (depends on 1)

Method as defined in claim 1 wherein said dewatering comprises processing said sludge in a vacuum filter mechanism.

### Claim 7 (depends on 1)

Method as defined in claim 1 wherein said dewatering comprises processing said sludge in a centrifuge.

### Claim 8 (depends on 1)

Method as defined in claim 1 wherein said dewatering comprises placing said sludge in a lagoon.

### Claim 9

Method of treating organic sludge of the type which has been treated to increase biological growth therein, comprising adding to said sludge an effective amount of a copolymer flocculant treatment, said copolymer consisting essentially of an acrylamide monomer and a cationic monomer, said cationic monomer comprising a quaternary ammonium salt of N,N dimethylaminoethylmethacrylate, wherein said cationic monomer is present in said copolymer in a molar ratio of about 80-90% cationic monomer: 20-10% acrylamide, said copolymer having an intrinsic viscosity of at least about 5 dl/g @ 30.degree. C. in 1 M NaCl, said method further comprising the step of dewatering said sludge.