Combination of captivator and fixed film bioreactor solutions

Patent metadata

Field	Value
Publication number	US-11447408-B2
Application number	US-201915734992-A
Country	US
Kind code	B2
Filing date	Jun 4, 2019
Priority date	Jun 5, 2018
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

A wastewater treatment system including a contact tank, a dissolved air flotation unit, a fixed film reactor, and a solids-liquid separation unit is disclosed. A method of treating wastewater with a dissolved air flotation unit and a fixed film reactor is also disclosed. A method of retrofitting a fixed film reactor wastewater treatment system including providing a contact tank and a dissolved air flotation unit is also disclosed. A method of facilitating increased operating efficiency of a fixed film wastewater treatment system including providing a dissolved air flotation unit is also disclosed.

First claim

What is claimed is:

1. A wastewater treatment system comprising: a contact tank having a first inlet fluidly connectable to a source of wastewater to be treated, a second inlet, and an outlet, the contact tank configured to treat the wastewater with waste sludge to form a mixed liquor; a dissolved air flotation unit having a first inlet fluidly connected to the outlet of the contact tank, a second inlet fluidly connectable to a source of gas, a floated solids outlet, and an effluent outlet, the dissolved air flotation unit configured to treat the mixed liquor with the gas to form floated solids and a dissolved air flotation unit effluent; a fixed film reactor having a first inlet fluidly connected to the effluent outlet of the dissolved air flotation unit, a second inlet, and an outlet, the fixed film reactor configured to form a fixed film effluent; a solid-liquid separation apparatus having an inlet fluidly connected to the outlet of the fixed film reactor, an effluent outlet, and a waste sludge outlet in fluid communication with the second inlet of the contact tank and the second inlet of the fixed film reactor; and a sludge mixing tank having a first inlet fluidly connected to the waste sludge outlet of the solid-liquid separation apparatus, a second inlet fluidly connected to the floated solids outlet of the dissolved air flotation unit, and an outlet fluidly connected to the second inlet of the contact tank.

2. The system of claim 1 , wherein the fixed film reactor is an aerobic biological reactor.

3. The system of claim 2 , wherein the fixed film reactor comprises media positioned within an aeration tank.

4. The system of claim 3 , wherein the fixed film reactor comprises at least one of a trickling filter, a rotating biological contactor, and a moving bed biological reactor.

5. The system of claim 2 , wherein the fixed film reactor comprises a media disk or panel.

6. The system of claim 2 , wherein the fixed film reactor comprises randomly packed moving media.

7. The system of claim 1 , wherein the sludge mixing tank has a third inlet fluidly connectable to a source of oxygen.

8. The system of claim 1 , further comprising a screen positioned between the source of the wastewater and the contact tank.

9. The system of claim 1 , wherein the fixed film effluent comprises about 50 mg/L to about 300 mg/L of biological solids.

10. The system of claim 1 , wherein the system is configured to produce the dissolved air flotation unit effluent having between about 60% to about 70% less total suspended solids (TSS) than the source of the wastewater to be treated which is directed to the contact tank.

11. The system of claim 10 , wherein the system is configured to produce the fixed film reactor effluent having at least about 20% less biochemical oxygen demand (BOD) than the dissolved air flotation unit effluent which is directed to the fixed film reactor.

12. A method of treating wastewater comprising:
introducing the wastewater and a waste sludge into a contact tank and mixing the wastewater with the waste sludge in the contact tank to form a mixed liquor;
directing at least a portion of the mixed liquor to a dissolved air flotation unit and separating the mixed liquor to form a dissolved air flotation unit effluent and waste biosolids;
directing the dissolved air flotation unit effluent to a fixed film reactor and biologically treating the dissolved air flotation unit effluent to form a fixed film effluent;
directing the fixed film effluent to a solid-liquid separation apparatus and separating the fixed film effluent to form a solids-lean effluent and the waste sludge;
selectively recycling a first portion of the waste sludge to a sludge mixing tank and a second portion of the waste sludge to the fixed film reactor;
directing the waste biosolids to the sludge mixing tank and mixing the waste biosolids with the first portion of the waste sludge to form a mixed sludge;
directing the mixed sludge to the contact tank; and
directing the solids-lean effluent to a treated wastewater outlet.

13. The method of claim 12 , further comprising introducing the waste sludge into a first region of the contact tank and introducing the wastewater into a second region of the contact tank, the first region positioned upstream from the second region.

14. The method of claim 13 , further comprising introducing a source of oxygen into the first region of the contact tank.

15. The method of claim 12 , further comprising separating non-biological waste solids from the wastewater.

16. The method of claim 12 , further comprising introducing at least one of a coagulant, a flocculant, or a ballast material to the fixed film effluent.

17. The method of claim 16 , further comprising separating the ballast material from the fixed film effluent.

18. The method of claim 12 , wherein separating the mixed liquor in the dissolved air flotation unit comprises reducing total suspended solids (TSS) of the mixed liquor by between about 60% and about 70% to form the dissolved air flotation unit effluent.

19. The method of claim 18 , wherein biologically treating the dissolved air flotation unit effluent comprises reducing biochemical oxygen demand (BOD) of the dissolved air flotation unit effluent by at least about 20% to form the fixed film effluent.

Assignees

• Evoqua Water Tech Llc

Inventors

• Erdogan Argun O
• Doyle michael l
• Hyke Deborah

Classifications

• C02F3/085

  Fluidized beds · CPC title

• C02F3/1215

  Combinations of activated sludge treatment with precipitation, flocculation, coagulation and separation of phosphates · CPC title

• C02F2301/043

  Treatment of partial or bypass streams · CPC title

• C02F2305/12

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

• C02F2209/08

  Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD] · CPC title