Microwave processing of wastewater sludge

Patent metadata

Field	Value
Publication number	US-2016355426-A1
Application number	US-201615244075-A
Country	US
Kind code	A1
Filing date	Aug 23, 2016
Priority date	Dec 21, 2011
Publication date	Dec 8, 2016
Grant date	—

Abstract

Methods for treatment of sludge with microwave irradiation for improving its dewatering are provided. In one embodiment, the method includes exposing the sludge to microwave irradiation at an absorbed power density of between about 7 W/ml and about 13 W/ml. Turbidity, total solids content and overall dewaterability are improved when the microwave irradiation treatment is combined with another method for dewatering sludge, such as enzyme treatment, conditioning with a flocculating agent and mechanical dewatering.

First claim

What is claimed is:

1 . A method for treating sludge, the method comprising:
exposing the sludge to microwave irradiation, wherein an absorbed power density in the sludge is 7 W/ml to about 13 W/ml.

2 . The method of claim 1 , wherein the microwave irradiation is at an absorbed power density of about 10 W/ml.

3 . The method of claim 1 , wherein the microwaves are in the frequency range of about 0.4 GHz to about 6 GHz.

4 . The method of claim 1 , wherein the microwaves are in the frequency range of about 0.915 GHz to about 2.45 GHz.

5 . The method of claim 1 , wherein the sludge is exposed to the microwave irradiation for about 1 second to about 60 seconds.

6 . The method of claim 1 , wherein the sludge is exposed to the microwave irradiation for about 5 seconds to about 50 seconds.

7 . The method of claim 1 , wherein the sludge is exposed to the microwave irradiation for about 10 seconds to about 30 seconds.

8 . The method of claim 1 , wherein an enzyme is mixed with the sludge prior to microwave irradiation exposure.

9 . The method of claim 1 , wherein a flocculating agent is mixed with the sludge following microwave irradiation.

10 . The method of claim 1 , further comprising subjecting the sludge to dewatering by mechanical means.

11 . The method of claim 1 , wherein the sludge is biological sludge.

12 . The method of claim 9 , wherein the enzyme is amylase.

13 . The method of claim 1 , wherein the microwave irradiation is applied as continuous wave irradiation.

14 . A method for dewatering sludge, the method comprising substantially sequentially:
a) adding a predetermined amount of an enzyme composition comprising a glucosidic polysaccharide hydrolyzing activity to form an enzyme-treated sludge; b) exposing the enzyme-treated sludge to microwave irradiation, wherein an absorbed power density in the sludge is 7 W/ml to about 13 W/ml; and c) exposing the irradiated sludge to mechanical dewatering.

15 . The method of claim 14 , wherein the microwave irradiation is at an absorbed power density of about 10 W/ml.

16 . The method of claim 14 , wherein the sludge is exposed to microwave irradiation for about 1 second to 50 seconds.

17 . The method of claim 14 , wherein the sludge is exposed to microwave irradiation for about 5 seconds to 40 seconds.

18 . The method of claim 14 , wherein the sludge is exposed to microwave irradiation for about 10 seconds to about 30 seconds.

Assignees

• Gen Electric

Inventors

• Neculaes Vasile Bogdan
• Vasconcellos Stephen Robert
• Moore Brian Christopher
• Murray Anthony John
• Klimash June
• Conway Kenneth Roger
• Paxon Tracy Lynn
• Salerno Michael Brian
• Renko Casey L

Classifications

• C02F1/42

  by ion-exchange (ion-exchange in general B01J) · CPC title

• C02F11/02

  Biological treatment · CPC title

• C02F3/342

  characterised by the enzymes used · CPC title

• C02F11/122

  using filter presses (C02F11/123 takes precedence) · CPC title

• C02F11/12 Primary

  by de-watering, drying or thickening · CPC title