Treatment using fixed film processes and ballasted settling

Patent metadata

Field	Value
Publication number	US-10919792-B2
Application number	US-201314405175-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Jun 11, 2012
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A system and method is provided for water and wastewater treatment. The system comprises a fixed film biological process and a ballasted flocculation process.

First claim

The invention claimed is:

1. A method for treating wastewater, comprising:
introducing a source of wastewater to a fixed film biological reactor to provide a fixed film effluent;
adding a magnetic ballast to the fixed film effluent to provide a ballasted effluent;
separating the ballasted effluent into a treated effluent and ballasted solids in a clarifier;
magnetically separating the ballasted solids into recovered ballast and ballast-free solids;
adding at least a portion of the ballast-free solids to the source of wastewater; and
adding at least a portion of the recovered ballast to the fixed film effluent,
wherein no cleaning solution is used for ballast recovery.

2. The method of claim 1 , further comprising adding a flocculant to the ballasted effluent.

3. The method of claim 1 , further comprising adding a coagulant to the fixed film effluent to provide a coagulated effluent.

4. The method of claim 3 , further comprising adding a portion of the ballast-free solids to at least one of the fixed film effluent, and the coagulated effluent.

5. The method of claim 3 , further comprising adding a portion of the ballasted solids to at least one of the source of wastewater, the fixed film effluent, and the coagulated effluent.

6. The method of claim 1 , wherein the fixed film effluent comprises 50 mg/l to 300 mg/l of biological solids.

7. The method of claim 1 , wherein the ballast comprises magnetite.

8. The method of claim 1 , wherein the wastewater is treated at a rate of between 200 gallons per day per square foot of a surface area of the clarifier to 6,000 gallons per day per square foot of the surface area of the clarifier.

9. The method of claim 1 , wherein the magnetic ballast has a particle size of less than 40 μm.

10. The method of claim 9 , wherein the magnetic ballast has a particle size of less than 20 μm.

11. The method of claim 1 , wherein the magnetic ballast is added in a dry or powdered form.

12. The method of claim 1 , further comprising subjecting the ballasted solids to mechanical shearing prior to magnetic separation.

13. The method of claim 1 , wherein at least one of a coagulation tank, a ballast feed tank, and a flocculation tank is integrated into the clarifier.

14. The method of claim 1 , further comprising bypassing the fixed film biological reactor during a high flow event.

15. The method of claim 1 , further comprising subjecting the wastewater to clarification upstream of the fixed film biological reactor.

Assignees

• Evoqua Water Tech Llc
• Antonneau Nathan
• Lindemann Timothy
• Schwingle Todd
• Whittier Michael Casey
• Woodard Steven E

Inventors

• Antonneau Nathan
• Lindemann Timothy
• Schwingle Todd
• Whittier Michael Casey
• Woodard Steven E

Classifications

• Y02W10/10

  Biological treatment of water, waste water, or sewage · CPC title

• C02F2305/12

  Inert solids used as ballast for improving sedimentation (C02F3/1226 takes precedence) · CPC title

• C02F9/00 Primary

  Multistage treatment of water, waste water or sewage · CPC title

• C02F2101/203

  Iron or iron compound · CPC title

• C02F3/121

  Multistep treatment · CPC title