INFILTRATION/INFLOW CONTROL FOR MEMBRANE BIOREACTOR

• US 20100191377A1
• Filed: 10/23/2007
• Published: 07/29/2010
• Est. Priority Date: 10/24/2006
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Smith, George W., Barnes, Dennis J.
• Granted Patent: US 8,293,098 B2
• Time in Patent Office: Days
• US Class Current: 700/271
• CPC Class Codes: C02F 3/121 Multistep treatment
• CPC Class Codes: C02F 3/1268 Membrane bioreactor systems
• CPC Class Codes: C02F 3/30 Aerobic and anaerobic processes
• CPC Class Codes: Y02W 10/10 Biological treatment of water, waste water, or sewage

Abstract

A wastewater treatment system comprising: a first treatment zone (11) fluidly connected to one or more further treatment zones (12-14), a membrane module (16) comprising a filter membrane is positioned in or fluidly connected to the further treatment zone; and a gravity settling device (15) fluidly connected to the first treatment zone (11) to receive overflow therefrom. A method of treating wastewater comprising flowing wastewater through one or more treatment zones (11-14) to produce a fluid product which is passed through a filter membrane (16) to produce a concentrated mixed liquor and a filtrate; returning at least a portion of the concentrated mixed liquor to at least one of the treatment zones (11); when the flow of wastewater water exceeds a predetermined level, flowing a portion of the returned mixed liquor to a gravity settling device (15) and clarifying the mixed liquor within the gravity settling device (15).

Claims

1. A wastewater treatment system, comprising:

a first treatment zone fluidly connected to one or more further treatment zones;

a membrane module comprising a filter membrane positioned in or fluidly connected to the further treatment zone; and

a gravity settling device fluidly connected to the first treatment zone to receive overflow therefrom.

2. A treatment system according to claim 1 comprising a plurality of treatment zones in series, with each treatment zone having the ability to maintain different food to micro-organism ratios and different dissolved oxygen concentrations.

3. A treatment system according to claim 1 further comprising an aeration system provided in one or more of the further treatment zones.

4. A treatment system according to claim 1 wherein the filter membrane comprises a porous hollow fiber membrane.

5. A treatment system according to claim 1 wherein the first treatment zone includes a fluidized media.

6. A treatment system according to claim 1 wherein the gravity settling device comprises a clarifier.

7. A treatment system according to claim 1 further comprising a equalization tank fluidly connected to the system.

8. A treatment system according to claim 1 comprising a pretreatment unit.

9. A treatment system according to claim 8 wherein the pretreatment unit comprises a floating solids trap and/or a chemical phosphorus removal unit.

10. A treatment system according to claim 1 wherein the treatment zones comprise one or more of the following:

an anaerobic zone, an anoxic zone, an aerated anoxic zone or an aerobic zone.

11. A treatment system according to claim 1 further comprising a fluid feedback line from a feed side of the membrane module to the first treatment zone and at least one of the further treatment zones.

12. A treatment system according to claim 1 further comprising:

a first fluid feedback line from at least one of the further treatment zones and the first treatment zone; and

a second fluid feedback line from a feed side of the membrane module to the at least one of the further treatment zones.

13. A treatment system according to claim 12 wherein the first fluid feedback line has an interconnecting pump.

14. A method of treating wastewater comprising the steps of:

flowing a wastewater through one or more treatment zones to produce a fluid product which is passed through a filter membrane to produce a concentrated mixed liquor and a filtrate;

returning at least a portion of the concentrated mixed liquor to at least one of the treatment zones; and

when the flow of wastewater water exceeds a predetermined level, flowing a portion of the returned mixed liquor to a gravity settling device and clarifying the mixed liquor within the gravity settling device.

15. The method according to claim 14 comprising returning sludge separated from the mixed liquor in the gravity settling device to a treatment zone downstream of the treatment zone feeding the gravity settling device.

16. The method according to claim 14 wherein the returned portion of the concentrated mix liquor is between about 2 times to about 8 times the average design flow of the system.

17. The method according to claim 14 wherein an effluent flow from one or more treatment tanks is split such that part of the flow is diverted to a clarifier and the remainder is treated by the filter membrane.

18. The method according to claim 17 wherein flow to the filter membrane is caused by gravity and wherein this flow is restricted such that liquid backs up in the upstream treatment zones.

19. The method according to claim 14 wherein a feedback flow from the feed side of the filter membrane is split such that part of the flow is diverted to an upstream treatment zone feeding a clarifier and the remainder is sent to a downstream treatment tanks that flows to the filter membrane.

20. The method according to claim 19 wherein the desired percentage of the feedback flow diverted to the clarifier is calculated by a programmable logic controller using a mass balance equation.