Method and apparatus for treatment of wastewater employing membrane bioreactors

• US 6,805,806 B2
• Filed: 12/11/2002
• Issued: 10/19/2004
• Est. Priority Date: 06/12/2001
• Status: Expired due to Fees

• Current Assignee: Hydrotreat, Inc.
• Original Assignee: Hydrotreat, Inc.
• Inventors: Arnaud, Johnny
• Primary Examiner(s): Reifsnyder, David A.
• Application Number:
  US10/317,018
• Publication Number:
  US 20030173275A1
• Time in Patent Office: 678 Days
• Field of Search: 210/143, 210/150, 210/151, 210/194, 210/195.1, 210/197, 210/195.3, 210/220, 210/252, 210/259, 210/295, 210/304, 210/321.67, 210/321.8, 210/621, 210/321.89, 210/512.1, 210/624, 210/623, 210/627, 210/788, 210/805, 210/806
• US Class Current: 210/788
• CPC Class Codes: B01D 21/2433 Discharge mechanisms for floating particles
• CPC Class Codes: B01D 21/245 Discharge mechanisms for the sediments
• CPC Class Codes: B01D 21/26 Separation of sediment aided by centrifugal force or centripetal forcecentrifuges B04B; cyclones B04C
• CPC Class Codes: B01D 21/267 by using a cyclone
• CPC Class Codes: B01D 21/305 Control of chemical properties of a component, e.g. control of pH
• CPC Class Codes: B01D 21/34 Controlling the feed distribution; Controlling the liquid level ; Control of process parameters
• CPC Class Codes: B01D 2311/04 Specific process operations in the feed stream; Feed pretreatment
• CPC Class Codes: B01D 2311/16 Flow or flux control
• CPC Class Codes: B01D 2311/2661 Addition of gas
• CPC Class Codes: B01D 2311/2688 Biological processes
• CPC Class Codes: B01D 2313/36 Energy sources
• CPC Class Codes: B01D 2315/02 Rotation or turning
• CPC Class Codes: B01D 61/145 Ultrafiltration
• CPC Class Codes: B01D 61/16 Feed pretreatment
• CPC Class Codes: B01D 63/06 Tubular membrane modules
• CPC Class Codes: B01D 63/16 Rotary, reciprocated or vibrated modules
• CPC Class Codes: B03D 1/028 Control and monitoring of flotation processes; computer models therefor
• CPC Class Codes: B03D 1/1418 using centrifugal forces
• CPC Class Codes: B03D 1/1431 Dissolved air flotation machines
• CPC Class Codes: C02F 1/38 by centrifugal separation
• CPC Class Codes: C02F 1/444 : by ultrafiltration or microfiltration
• CPC Class Codes: C02F 3/1268 : Membrane bioreactor systems
• CPC Class Codes: E21B 43/166 : Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium CO2 injection E21B43/164; steam injection E21B43/24
• CPC Class Codes: Y02W 10/10 : Biological treatment of water, waste water, or sewage

Abstract

Methods and apparatus employing membrane filtration in biodegradation processes for treatment of wastewater are described. A bioreactor system is described having an equalization system, a membrane bioreactor system, and a controller. Aeration systems for a membrane bioreactor, such as a mixer, and an ultrafilter subsystem are also described, as is a rotary membrane ultrafilter.

Claims

1. A fluid treatment system for removing contaminants from wastewater, comprising:

a controller adapted to control the flow of biomass into the system; and

a bioreactor system, the bioreactor system having

a vessel having an upper and lower portion for containing biomass;

a cyclone filter to separate the biomass into bulk liquid and bulk slurry;

at least one membrane filter having a membrane; and

a dissolved gas generator having an oxygen supply,

wherein biomass exits the lower portion of the vessel into the cyclone filter, the cyclone filter separating the biomass into bulk liquid and bulk slurry, the bulk liquid passing through the membrane filter and into the dissolved gas generator,

the dissolved gas generator saturating the bulk liquid with oxygen from the oxygen supply, the bulk liquid saturated with oxygen being returned to the upper portion of the vessel.

2. The fluid treatment system of claim 1 further comprising at least one mixer within the vessel, the at least one mixer adapted to mix the bulk liquid saturated with oxygen from the dissolved gas generator with biomass provided from the lower portion of the vessel by a manifold, and returning the saturated liquid mixed with the biomass to the vessel.

3. The fluid treatment system of claim 2, wherein the biomass supplied to the bioreactor system is provided by an equalization system to consolidate a plurality of wastewater streams into one biomass supply.

4. The fluid treatment system of claim 2 further comprising a piping manifold to provide fluid communication from the lower portion of the vessel to the at least one mixer, the at least one mixer mixing the liquid saturated with oxygen from the dissolved gas generator with the biomass.

5. The fluid treatment system of claim 4 further comprising piping for removing the water removed from the bulk liquid by the membrane from the bioreactor system.

6. The fluid treatment system of claim 4 wherein a pump removes the biomass from the lower portion of the vessel and pumps the biomass into the cyclone filter.

7. The fluid treatment system of claim 6, wherein the bulk slurry from the cyclone filter is returned to the upper portion of the vessel.

8. The fluid treatment system of claim 7 wherein the oxygen supply is selected from the group consisting of a compressor, bottled oxygen, or a membrane separator to remove nitrogen from atmospheric air.

9. The fluid treatment system of claim 8, wherein the equalization system further comprises:

a collection tank adapted to receive wastewater;

a plurality of equalization system dissolved oxygen systems, each of said dissolved oxygen system comprising

an equalization system pump to pump biomass from the collection tank into an equalization system cyclone filter, the equalization system cyclone filter adapted to separate the biomass into liquid and slurry;

an equalization system dissolved gas generator to saturate the liquid with oxygen; and

a distributor within the collection tank to return the liquid saturated with dissolved oxygen from equalization system dissolved gas generator to the collection tank,

wherein the equalization system consolidates biomass from each of the plurality of equalization system dissolved oxygen systems into one uniform supply of biomass for the bioreactor system.

10. The fluid treatment system of claim 9 wherein each of the equalization system dissolved gas generators further comprises a radial grooved ring and each of the equalization system cyclone filters further comprises a spiral grooved ring.

11. The fluid treatment system of 8 further comprising a first oxygen sensor between the vessel and the pump and a second oxygen sensor between the dissolved gas generator and the mixer, each oxygen sensor in communication with the controller, the controller adjusting the flow of biomass into the vessel and oxygen supplied to the dissolved gas generator in response to said sensors.

12. The fluid treatment system of claim 11 wherein the mixer comprises a radial grooved ring.

13. The fluid treatment system of claim 11, wherein the dissolved gas generator further comprises:

an upper cylindrical donut housing with a fluid inlet, the upper cylindrical donut housing having a gas separation chamber to separate excess oxygen from the bulk liquid for discharging oxygen through a gas outlet on the upper housing;

a grooved ring having a plurality of grooves, an impact zone being located below the grooved ring,

the grooved ring being concentric to the upper cylindrical donut housing, the grooved ring having an outer diameter on a first end that is smaller than a diameter of the upper cylindrical donut housing, thus defining a distribution channel;

an orifice ring adapted to inject oxygen in the bulk liquid leaving the grooves; and

a cylinder concentric with the grooved ring, the cylinder in fluid communication with the distribution channel via the grooves, a saturated liquid outlet being located at a bottom of the cylinder.

14. The fluid treatment system of claim 13, wherein the grooves are radial.

15. The fluid treatment system of claim 11, wherein the cyclone filter further comprises:

an inlet for receiving the biomass;

a spiral grooved ring having a plurality of grooves;

a cylinder connected to a lower cone, the ring being concentric with the cylinder, the lower cone having a solids outlet located on a lower end for removing the bulk slurry, the cylinder adapted to receive the biomass from the grooves, the ring having an outer diameter that is smaller than a diameter of the cylinder, thus defining a distribution channel; and

an inner short skirt being coaxial with the cylinder, the skirt having one end disposed inside the cylinder to define a down-flow annulus between the skirt and the cylinder, the skirt having another end extending upwardly out of the cylinder to allow the bulk liquid to exit the cyclone filter.

16. The fluid treatment system of claim 15 in which the grooves in the ring spiral involutely.

17. The fluid treatment system of claim 16 in which the cyclone filter further comprises an inner diameter of the ring being substantially equal to a diameter of the end of the skirt extending upwardly out of the cylinder.

18. The fluid treatment system of 16 in which the inlet of the cyclone filter is radially disposed on the cylinder.

19. The fluid treatment system of claim 18 wherein the vessel is vented to the atmosphere to operate at atmospheric pressure.

20. A method of removing contaminants from wastewater, comprising:

controlling the flow of biomass into the system with a controller;

containing biomass in a vessel having an upper and lower portion;

separating the biomass into bulk liquid and bulk slurry with a cyclone filter;

providing at least one membrane filter having a membrane; and

providing a dissolved gas generator having an oxygen supply, wherein biomass exits the lower portion of the vessel into the cyclone filter, the cyclone filter separating the biomass into bulk liquid and bulk slurry, the bulk liquid passing through the membrane filter and into the dissolved gas generator, the dissolved gas generator saturating the bulk liquid with oxygen from the oxygen supply, the bulk liquid saturated with oxygen being returned to the upper portion of the vessel.

21. The method of claim 20 further comprising:

mixing, with at least one mixer, the bulk liquid saturated with oxygen from the dissolved gas generator with biomass provided from the lower portion of the vessel via a manifold; and

,

returning the saturated liquid mixed with the biomass to the vessel.

22. The method of claim 21 further comprising returning the bulk slurry from the cyclone filter to the upper portion of the vessel.

23. The method of claim 22 further comprising removing nitrogen from the atmospheric air with a compressor, bottled oxygen, or a membrane separator.

24. The method of claim 20 further comprising:

providing fluid from the lower portion of the vessel to the at least one mixer via a piping manifold; and

mixing, with at least one mixer, the liquid saturated with oxygen from the dissolved gas generator with the biomass.

25. The method of claim 20 further comprising adjusting the flow of biomass into the vessel and oxygen supplied to the dissolved gas generator.

26. The method of claim 25 in which the steps of providing a dissolved gas generator further comprises providing the dissolved gas generator having

an upper cylindrical donut housing with a fluid inlet, the upper cylindrical donut housing having a gas separation chamber to separate excess oxygen from the bulk liquid for discharging oxygen through a gas outlet on the upper housing;

a grooved ring having a plurality of grooves, an impact;

zone being located below the grooved ring,

the grooved ring being concentric to the upper cylindrical donut housing, the grooved ring having an outer diameter on a first end that is smaller than a diameter of the upper cylindrical donut housing, thus defining a distribution channel;

an orifice ring adapted to inject oxygen in the bulk liquid leaving the grooves; and

a cylinder concentric with the grooved ring, the cylinder in fluid communication with the distribution channel via the grooves, a saturated liquid outlet being located at a bottom of the cylinder.

27. The method of claim 26 in which the step of separating with a cyclone filter further comprises providing the cyclone filter having:

an inlet for receiving the biomass;

a spiral grooved ring having a plurality of grooves;

a cylinder connected to a lower cone, the ring being concentric with the cylinder, the lower cone having a solids outlet located on a lower end for removing the bulk slurry, the cylinder adapted to receive the biomass from the grooves, the ring having an outer diameter that is smaller than a diameter of the cylinder, thus defining a distribution channel; and

an inner short skirt being coaxial with the cylinder, the skirt having one cad disposed inside the cylinder to define a down-flow annulus between the skin and the cylinder, the skirt having another end extending upwardly out of the cylinder to allow the bulk liquid to exit the cyclone filter.

28. The method of claim 27 further comprising supplying biomass to the bioreactor system by an equalization system to consolidate a plurality of wastewater streams into one biomass supply.