Method and apparatus for treatment of water and wastewater

• US 20020088758A1
• Filed: 11/02/2001
• Published: 07/11/2002
• Est. Priority Date: 11/02/2000
• Status: Active Grant

• Current Assignee: I. Kruger Inc.
• Original Assignee: I. Kruger Inc.
• Inventors: Blumenschein, Charles D., Banerjee, Kashi
• Granted Patent: US 6,919,031 B2
• Time in Patent Office: Days
• US Class Current: 210/712
• CPC Class Codes: C02F 1/38 by centrifugal separation
• CPC Class Codes: C02F 1/5245 using basic salts, e.g. of aluminium and iron
• CPC Class Codes: C02F 2001/007 Processes including a sedimentation step
• CPC Class Codes: C02F 2101/20 Heavy metals or heavy metal compounds
• CPC Class Codes: C02F 2305/12 Inert solids used as ballast for improving sedimentation C02F3/1226 takes precedence
• CPC Class Codes: C02F 5/02 Softening water by precipitation of the hardness
• CPC Class Codes: Y10S 210/912 Heavy metal

Abstract

The present invention is directed to a method and apparatus for the treatment of water and wastewater. In one embodiment, a method of treating water according to the present invention includes mixing sludge and precipitant with the water to be treated, mixing ballast with the water, and separating the water into treated water and sludge. Some or all of the separated sludge may be recycled for mixing with the precipitant and water to be treated.

Claims

1. A method for treating water comprising:

reacting an alkaline reagent with a first sludge to form a treatment slurry;

reacting the treatment slurry with a water to form a treated water and suspended solids;

mixing the treated water and the suspended solids with an insoluble granular material;

destabilizing the treated water, the suspended solids and the insoluble granular material;

flocculating the treated water, the suspended solids and the insoluble granular material; and

separating the treated water, the suspended solids and the insoluble granular material into clarified water and a second sludge.

2. The method of claim 1, wherein at least a portion of the second sludge is recycled for use as the first sludge.

3. The method of claim 1, further comprising:

separating at least a portion of the insoluble granular material from the second sludge; and

recycling the at least a portion of the insoluble granular material to be mixed with the treated water and suspended solids.

4. The method of claim 3 further comprising separating at least a portion of the insoluble granular material from the second sludge by applying a centrifugal force to the second sludge.

5. The method of claim 3 further comprising separating at least a portion of the insoluble granular material from the second sludge by applying a gravitational force to the second sludge.

6. The method of claim 5, further comprising shearing the second sludge and insoluble granular material prior to separating at least a portion of the insoluble granular material from the second sludge by applying a gravitational force to the second sludge.

7. The method of claim 1, wherein the water is acidic and comprises dissolved metals.

8. The method of claim 1, wherein the water comprises dissolved calcium and magnesium.

9. The method of claim 1, wherein the alkaline reagent is selected from the group consisting of calcium hydroxide, magnesium hydroxide, sodium hydroxide, sodium carbonate, and mixtures thereof.

10. The method of claim 1, further comprising reacting a second reagent with the first sludge.

11. The method of claim 1, wherein destabilizing the treated water, the suspended solids and the insoluble granular material comprises adding a coagulating agent.

12. The method of claim 1, wherein the insoluble granular material is active chemically or biologically.

14. The water treatment system of claim 13, further comprising:

a sludge separator connected to the sludge outlet and provided with a granular insoluble material outlet and a separated sludge outlet;

a separated sludge recycle connected to the separated sludge outlet and the recycle sludge inlet; and

a insoluble granular material recycle connected to the insoluble granular material outlet and the insoluble granular material inlet.

15. The water treatment system of claim 14, wherein the sludge separator comprises a centrifugal separator.

16. The water treatment system of claim 14, wherein the sludge separator comprises a gravity sedimentation tank.

17. The water treatment system of claim 14, wherein the sludge separator comprises:

a high shear pump; and

a gravity sedimentation tank.

19. The method of claim 18, wherein mixing the first sludge and the precipitant with the water is performed before mixing the ballast with the water.

20. The method of claim 19, wherein mixing the ballast with the water is performed before separating the water into treated water and the second sludge.

21. The method of claim 18, further comprising;

mixing the first sludge and the precipitant with one another prior to mixing them with the water.

22. The method of claim 21, wherein mixing the first sludge and the precipitant with one another prior to mixing them with the water further comprises mixing the first sludge and an alkaline reagent.

23. The method of claim 18, further comprising:

mixing a coagulant with the water.

24. The method of claim 23, wherein mixing the coagulant with the water is performed after mixing the ballast with the water.

25. The method of claim 18, further comprising recycling at least a portion of the second sludge for use as the first sludge.

26. The method of claim 18, further comprising separating at least a portion of the ballast from the second sludge before recycling the second sludge.

27. The method of claim 26, further comprising recycling the at least a portion of the ballast.

13. A water treatment system comprising:

an alkaline reagent mixing chamber provided with an alkaline reagent inlet, a recycle sludge inlet, an agitator and a treatment slurry outlet;

a reaction chamber connected to the treatment slurry outlet and provided with a water inlet, an agitator and a treated water and suspended solids outlet;

a flash mix chamber connected to the treated water and suspended solids outlet and provided with an insoluble granular material inlet, an agitator and a treated water, suspended solids and granular insoluble material outlet;

a flocculation chamber connected to the treated water, suspended solids and granular insoluble material outlet and provided with an agitator and a flocculated water outlet;

a separator connected to the flocculated water outlet and provided with a clarified liquid outlet and a sludge outlet;

a sludge recycle connected to the sludge outlet and the recycle sludge inlet; and

a sludge discharge connected to the sludge outlet.

18. A method of treating water, comprising:

mixing a first sludge and a precipitant with a water to be treated;

mixing a ballast with the water; and

separating the water into clarified water and a second sludge.